diff --git a/src/generators/Generator.ts b/src/generators/Generator.ts
index 1a1528d0c42d..6eff2f2a3d7e 100644
--- a/src/generators/Generator.ts
+++ b/src/generators/Generator.ts
@@ -1,5 +1,7 @@
 import MagicString, { Bundle } from 'magic-string';
 import { walk } from 'estree-walker';
+import { getLocator } from 'locate-character';
+import getCodeFrame from '../utils/getCodeFrame';
 import isReference from '../utils/isReference';
 import flattenReference from '../utils/flattenReference';
 import globalWhitelist from '../utils/globalWhitelist';
@@ -13,6 +15,8 @@ import annotateWithScopes from '../utils/annotateWithScopes';
 import clone from '../utils/clone';
 import DomBlock from './dom/Block';
 import SsrBlock from './server-side-rendering/Block';
+import { walkRules } from '../utils/css';
+import Selector from './Selector';
 import { Node, Parsed, CompileOptions } from '../interfaces';
 
 const test = typeof global !== 'undefined' && global.__svelte_test;
@@ -40,6 +44,8 @@ export default class Generator {
 	cssId: string;
 	usesRefs: boolean;
 
+	selectors: Selector[];
+
 	importedNames: Set<string>;
 	aliases: Map<string, string>;
 	usedNames: Set<string>;
@@ -71,10 +77,21 @@ export default class Generator {
 		this.expectedProperties = new Set();
 
 		this.code = new MagicString(source);
+		this.usesRefs = false;
+
+		// styles
 		this.cascade = options.cascade !== false; // TODO remove this option in v2
 		this.css = parsed.css ? processCss(parsed, this.code, this.cascade) : null;
 		this.cssId = parsed.css ? `svelte-${parsed.hash}` : '';
-		this.usesRefs = false;
+		this.selectors = [];
+
+		if (parsed.css) {
+			walkRules(parsed.css.children, node => {
+				node.selector.children.forEach((child: Node) => {
+					this.selectors.push(new Selector(child));
+				});
+			});
+		}
 
 		// allow compiler to deconflict user's `import { get } from 'whatever'` and
 		// Svelte's builtin `import { get, ... } from 'svelte/shared.ts'`;
@@ -211,6 +228,20 @@ export default class Generator {
 		};
 	}
 
+	applyCss(node: Node, stack: Node[]) {
+		if (!this.cssId) return;
+
+		if (this.cascade) {
+			if (stack.length === 0) node._needsCssAttribute = true;
+			return;
+		}
+
+		for (let i = 0; i < this.selectors.length; i += 1) {
+			const selector = this.selectors[i];
+			selector.apply(node, stack);
+		}
+	}
+
 	findDependencies(
 		contextDependencies: Map<string, string[]>,
 		indexes: Map<string, string>,
@@ -590,4 +621,31 @@ export default class Generator {
 		this.namespace = namespace;
 		this.templateProperties = templateProperties;
 	}
+
+	warnOnUnusedSelectors() {
+		if (this.cascade) return;
+
+		let locator;
+
+		this.selectors.forEach((selector: Selector) => {
+			if (!selector.used) {
+				const pos = selector.node.start;
+
+				if (!locator) locator = getLocator(this.source);
+				const { line, column } = locator(pos);
+
+				const frame = getCodeFrame(this.source, line, column);
+				const message = `Unused CSS selector`;
+
+				this.options.onwarn({
+					message,
+					frame,
+					loc: { line: line + 1, column },
+					pos,
+					filename: this.options.filename,
+					toString: () => `${message} (${line + 1}:${column})\n${frame}`,
+				});
+			}
+		});
+	}
 }
diff --git a/src/generators/Selector.ts b/src/generators/Selector.ts
new file mode 100644
index 000000000000..862bbea650a4
--- /dev/null
+++ b/src/generators/Selector.ts
@@ -0,0 +1,150 @@
+import { groupSelectors, isGlobalSelector, walkRules } from '../utils/css';
+import { Node } from '../interfaces';
+
+export default class Selector {
+	node: Node;
+	blocks: Node[][];
+	parts: Node[];
+	used: boolean;
+
+	constructor(node: Node) {
+		this.node = node;
+
+		this.blocks = groupSelectors(this.node);
+
+		// take trailing :global(...) selectors out of consideration
+		let i = node.children.length;
+		while (i > 2) {
+			const last = node.children[i-1];
+			const penultimate = node.children[i-2];
+
+			if (last.type === 'PseudoClassSelector' && last.name === 'global') {
+				i -= 2;
+			} else {
+				break;
+			}
+		}
+
+		this.parts = node.children.slice(0, i);
+
+		this.used = isGlobalSelector(this.blocks[0]);
+	}
+
+	apply(node: Node, stack: Node[]) {
+		const applies = selectorAppliesTo(this.parts, node, stack.slice());
+
+		if (applies) {
+			this.used = true;
+
+			// add svelte-123xyz attribute to outermost and innermost
+			// elements — no need to add it to intermediate elements
+			node._needsCssAttribute = true;
+			if (stack[0] && this.node.children.find(isDescendantSelector)) stack[0]._needsCssAttribute = true;
+		}
+	}
+}
+
+function isDescendantSelector(selector: Node) {
+	return selector.type === 'WhiteSpace' || selector.type === 'Combinator';
+}
+
+function selectorAppliesTo(parts: Node[], node: Node, stack: Node[]): boolean {
+	let i = parts.length;
+	let j = stack.length;
+
+	while (i--) {
+		if (!node) {
+			return parts.every((part: Node) => {
+				return part.type === 'Combinator' || (part.type === 'PseudoClassSelector' && part.name === 'global');
+			});
+		}
+
+		const part = parts[i];
+
+		if (part.type === 'PseudoClassSelector' && part.name === 'global') {
+			// TODO shouldn't see this here... maybe we should enforce that :global(...)
+			// cannot be sandwiched between non-global selectors?
+			return false;
+		}
+
+		if (part.type === 'PseudoClassSelector' || part.type === 'PseudoElementSelector') {
+			continue;
+		}
+
+		if (part.type === 'ClassSelector') {
+			if (!attributeMatches(node, 'class', part.name, '~=', false)) return false;
+		}
+
+		else if (part.type === 'IdSelector') {
+			if (!attributeMatches(node, 'id', part.name, '=', false)) return false;
+		}
+
+		else if (part.type === 'AttributeSelector') {
+			if (!attributeMatches(node, part.name.name, part.value && unquote(part.value.value), part.operator, part.flags)) return false;
+		}
+
+		else if (part.type === 'TypeSelector') {
+			if (part.name === '*') return true;
+			if (node.name !== part.name) return false;
+		}
+
+		else if (part.type === 'WhiteSpace') {
+			parts = parts.slice(0, i);
+
+			while (stack.length) {
+				if (selectorAppliesTo(parts, stack.pop(), stack)) {
+					return true;
+				}
+			}
+
+			return false;
+		}
+
+		else if (part.type === 'Combinator') {
+			if (part.name === '>') {
+				return selectorAppliesTo(parts.slice(0, i), stack.pop(), stack);
+			}
+
+			// TODO other combinators
+			return true;
+		}
+
+		else {
+			// bail. TODO figure out what these could be
+			return true;
+		}
+	}
+
+	return true;
+}
+
+const operators = {
+	'=' : (value: string, flags: string) => new RegExp(`^${value}$`, flags),
+	'~=': (value: string, flags: string) => new RegExp(`\\b${value}\\b`, flags),
+	'|=': (value: string, flags: string) => new RegExp(`^${value}(-.+)?$`, flags),
+	'^=': (value: string, flags: string) => new RegExp(`^${value}`, flags),
+	'$=': (value: string, flags: string) => new RegExp(`${value}$`, flags),
+	'*=': (value: string, flags: string) => new RegExp(value, flags)
+};
+
+function attributeMatches(node: Node, name: string, expectedValue: string, operator: string, caseInsensitive: boolean) {
+	const attr = node.attributes.find((attr: Node) => attr.name === name);
+	if (!attr) return false;
+	if (attr.value === true) return operator === null;
+	if (isDynamic(attr.value)) return true;
+
+	const actualValue = attr.value[0].data;
+
+	const pattern = operators[operator](expectedValue, caseInsensitive ? 'i' : '');
+	return pattern.test(actualValue);
+}
+
+function isDynamic(value: Node) {
+	return value.length > 1 || value[0].type !== 'Text';
+}
+
+function unquote(str: string) {
+	if (str[0] === str[str.length - 1] && str[0] === "'" || str[0] === '"') {
+		return str.slice(1, str.length - 1);
+	}
+}
\ No newline at end of file
diff --git a/src/generators/dom/index.ts b/src/generators/dom/index.ts
index fe0b3857f243..2810f2cbd143 100644
--- a/src/generators/dom/index.ts
+++ b/src/generators/dom/index.ts
@@ -61,8 +61,10 @@ export default function dom(
 
 	const { block, state } = preprocess(generator, namespace, parsed.html);
 
+	generator.warnOnUnusedSelectors();
+
 	parsed.html.children.forEach((node: Node) => {
-		visit(generator, block, state, node);
+		visit(generator, block, state, node, []);
 	});
 
 	const builder = new CodeBuilder();
diff --git a/src/generators/dom/preprocess.ts b/src/generators/dom/preprocess.ts
index 55a057b9e444..e4ea6f8f9fb6 100644
--- a/src/generators/dom/preprocess.ts
+++ b/src/generators/dom/preprocess.ts
@@ -40,6 +40,7 @@ const preprocessors = {
 		block: Block,
 		state: State,
 		node: Node,
+		elementStack: Node[],
 		stripWhitespace: boolean
 	) => {
 		const dependencies = block.findDependencies(node.expression);
@@ -55,6 +56,7 @@ const preprocessors = {
 		block: Block,
 		state: State,
 		node: Node,
+		elementStack: Node[],
 		stripWhitespace: boolean
 	) => {
 		const dependencies = block.findDependencies(node.expression);
@@ -66,7 +68,14 @@ const preprocessors = {
 		node._state = getChildState(state, { basename, name });
 	},
 
-	Text: (generator: DomGenerator, block: Block, state: State, node: Node, stripWhitespace: boolean) => {
+	Text: (
+		generator: DomGenerator,
+		block: Block,
+		state: State,
+		node: Node,
+		elementStack: Node[],
+		stripWhitespace: boolean
+	) => {
 		node._state = getChildState(state);
 
 		if (!/\S/.test(node.data)) {
@@ -83,6 +92,7 @@ const preprocessors = {
 		block: Block,
 		state: State,
 		node: Node,
+		elementStack: Node[],
 		stripWhitespace: boolean,
 		nextSibling: Node
 	) => {
@@ -102,7 +112,7 @@ const preprocessors = {
 			node._state = getChildState(state);
 
 			blocks.push(node._block);
-			preprocessChildren(generator, node._block, node._state, node, stripWhitespace, node);
+			preprocessChildren(generator, node._block, node._state, node, elementStack, stripWhitespace, nextSibling);
 
 			if (node._block.dependencies.size > 0) {
 				dynamic = true;
@@ -127,6 +137,7 @@ const preprocessors = {
 					node.else._block,
 					node.else._state,
 					node.else,
+					elementStack,
 					stripWhitespace,
 					nextSibling
 				);
@@ -154,6 +165,7 @@ const preprocessors = {
 		block: Block,
 		state: State,
 		node: Node,
+		elementStack: Node[],
 		stripWhitespace: boolean,
 		nextSibling: Node
 	) => {
@@ -202,7 +214,7 @@ const preprocessors = {
 		});
 
 		generator.blocks.push(node._block);
-		preprocessChildren(generator, node._block, node._state, node, stripWhitespace, nextSibling);
+		preprocessChildren(generator, node._block, node._state, node, elementStack, stripWhitespace, nextSibling);
 		block.addDependencies(node._block.dependencies);
 		node._block.hasUpdateMethod = node._block.dependencies.size > 0;
 
@@ -219,6 +231,7 @@ const preprocessors = {
 				node.else._block,
 				node.else._state,
 				node.else,
+				elementStack,
 				stripWhitespace,
 				nextSibling
 			);
@@ -231,6 +244,7 @@ const preprocessors = {
 		block: Block,
 		state: State,
 		node: Node,
+		elementStack: Node[],
 		stripWhitespace: boolean,
 		nextSibling: Node
 	) => {
@@ -315,6 +329,8 @@ const preprocessors = {
 					: state.namespace,
 				allUsedContexts: [],
 			});
+
+			generator.applyCss(node, elementStack);
 		}
 
 		if (node.children.length) {
@@ -328,12 +344,12 @@ const preprocessors = {
 				});
 
 				generator.blocks.push(node._block);
-				preprocessChildren(generator, node._block, node._state, node, stripWhitespace, nextSibling);
+				preprocessChildren(generator, node._block, node._state, node, elementStack, stripWhitespace, nextSibling);
 				block.addDependencies(node._block.dependencies);
 				node._block.hasUpdateMethod = node._block.dependencies.size > 0;
 			} else {
 				if (node.name === 'pre' || node.name === 'textarea') stripWhitespace = false;
-				preprocessChildren(generator, block, node._state, node, stripWhitespace, nextSibling);
+				preprocessChildren(generator, block, node._state, node, elementStack.concat(node), stripWhitespace, nextSibling);
 			}
 		}
 	},
@@ -344,6 +360,7 @@ function preprocessChildren(
 	block: Block,
 	state: State,
 	node: Node,
+	elementStack: Node[],
 	stripWhitespace: boolean,
 	nextSibling: Node
 ) {
@@ -373,7 +390,7 @@ function preprocessChildren(
 
 	cleaned.forEach((child: Node, i: number) => {
 		const preprocessor = preprocessors[child.type];
-		if (preprocessor) preprocessor(generator, block, state, child, stripWhitespace, cleaned[i + 1] || nextSibling);
+		if (preprocessor) preprocessor(generator, block, state, child, elementStack, stripWhitespace, cleaned[i + 1] || nextSibling);
 
 		if (lastChild) {
 			lastChild.next = child;
@@ -432,7 +449,7 @@ export default function preprocess(
 	};
 
 	generator.blocks.push(block);
-	preprocessChildren(generator, block, state, node, true, null);
+	preprocessChildren(generator, block, state, node, [], true, null);
 	block.hasUpdateMethod = block.dependencies.size > 0;
 
 	return { block, state };
diff --git a/src/generators/dom/visit.ts b/src/generators/dom/visit.ts
index 91601fa8fd91..82fc23c03b17 100644
--- a/src/generators/dom/visit.ts
+++ b/src/generators/dom/visit.ts
@@ -2,13 +2,15 @@ import visitors from './visitors/index';
 import { DomGenerator } from './index';
 import Block from './Block';
 import { Node } from '../../interfaces';
+import { State } from './interfaces';
 
 export default function visit(
 	generator: DomGenerator,
 	block: Block,
-	state,
-	node: Node
+	state: State,
+	node: Node,
+	elementStack: Node[]
 ) {
 	const visitor = visitors[node.type];
-	visitor(generator, block, state, node);
+	visitor(generator, block, state, node, elementStack);
 }
diff --git a/src/generators/dom/visitors/Component/Component.ts b/src/generators/dom/visitors/Component/Component.ts
index 557cc41a1c37..7145f5de36d7 100644
--- a/src/generators/dom/visitors/Component/Component.ts
+++ b/src/generators/dom/visitors/Component/Component.ts
@@ -40,7 +40,8 @@ export default function visitComponent(
 	generator: DomGenerator,
 	block: Block,
 	state: State,
-	node: Node
+	node: Node,
+	elementStack: Node[]
 ) {
 	const hasChildren = node.children.length > 0;
 	const name = block.getUniqueName(
@@ -121,7 +122,7 @@ export default function visitComponent(
 		const childBlock = node._block;
 
 		node.children.forEach((child: Node) => {
-			visit(generator, childBlock, childState, child);
+			visit(generator, childBlock, childState, child, elementStack);
 		});
 
 		const yieldFragment = block.getUniqueName(`${name}_yield_fragment`);
diff --git a/src/generators/dom/visitors/EachBlock.ts b/src/generators/dom/visitors/EachBlock.ts
index 82a117eaae82..db26f10475a8 100644
--- a/src/generators/dom/visitors/EachBlock.ts
+++ b/src/generators/dom/visitors/EachBlock.ts
@@ -9,7 +9,8 @@ export default function visitEachBlock(
 	generator: DomGenerator,
 	block: Block,
 	state: State,
-	node: Node
+	node: Node,
+	elementStack: Node[]
 ) {
 	const each_block = generator.getUniqueName(`each_block`);
 	const create_each_block = node._block.name;
@@ -117,12 +118,12 @@ export default function visitEachBlock(
 	}
 
 	node.children.forEach((child: Node) => {
-		visit(generator, node._block, node._state, child);
+		visit(generator, node._block, node._state, child, elementStack);
 	});
 
 	if (node.else) {
 		node.else.children.forEach((child: Node) => {
-			visit(generator, node.else._block, node.else._state, child);
+			visit(generator, node.else._block, node.else._state, child, elementStack);
 		});
 	}
 }
diff --git a/src/generators/dom/visitors/Element/Element.ts b/src/generators/dom/visitors/Element/Element.ts
index 53b4df6fdd26..bb7de853bb56 100644
--- a/src/generators/dom/visitors/Element/Element.ts
+++ b/src/generators/dom/visitors/Element/Element.ts
@@ -35,14 +35,15 @@ export default function visitElement(
 	generator: DomGenerator,
 	block: Block,
 	state: State,
-	node: Node
+	node: Node,
+	elementStack: Node[]
 ) {
 	if (node.name in meta) {
 		return meta[node.name](generator, block, node);
 	}
 
 	if (generator.components.has(node.name) || node.name === ':Self') {
-		return visitComponent(generator, block, state, node);
+		return visitComponent(generator, block, state, node, elementStack);
 	}
 
 	const childState = node._state;
@@ -80,7 +81,8 @@ export default function visitElement(
 	}
 
 	// add CSS encapsulation attribute
-	if (generator.cssId && (!generator.cascade || state.isTopLevel)) {
+	// TODO add a helper for this, rather than repeating it
+	if (node._needsCssAttribute) {
 		block.builders.hydrate.addLine(
 			`@setAttribute( ${name}, '${generator.cssId}', '' );`
 		);
@@ -181,7 +183,7 @@ export default function visitElement(
 	}
 
 	node.children.forEach((child: Node) => {
-		visit(generator, block, childState, child);
+		visit(generator, block, childState, child, elementStack.concat(node));
 	});
 
 	if (node.lateUpdate) {
diff --git a/src/generators/dom/visitors/IfBlock.ts b/src/generators/dom/visitors/IfBlock.ts
index ddac9800b53e..75b88e363fa9 100644
--- a/src/generators/dom/visitors/IfBlock.ts
+++ b/src/generators/dom/visitors/IfBlock.ts
@@ -19,7 +19,8 @@ function getBranches(
 	generator: DomGenerator,
 	block: Block,
 	state: State,
-	node: Node
+	node: Node,
+	elementStack: Node[]
 ) {
 	const branches = [
 		{
@@ -31,11 +32,11 @@ function getBranches(
 		},
 	];
 
-	visitChildren(generator, block, state, node);
+	visitChildren(generator, block, state, node, elementStack);
 
 	if (isElseIf(node.else)) {
 		branches.push(
-			...getBranches(generator, block, state, node.else.children[0])
+			...getBranches(generator, block, state, node.else.children[0], elementStack)
 		);
 	} else {
 		branches.push({
@@ -47,7 +48,7 @@ function getBranches(
 		});
 
 		if (node.else) {
-			visitChildren(generator, block, state, node.else);
+			visitChildren(generator, block, state, node.else, elementStack);
 		}
 	}
 
@@ -58,10 +59,11 @@ function visitChildren(
 	generator: DomGenerator,
 	block: Block,
 	state: State,
-	node: Node
+	node: Node,
+	elementStack: Node[]
 ) {
 	node.children.forEach((child: Node) => {
-		visit(generator, node._block, node._state, child);
+		visit(generator, node._block, node._state, child, elementStack);
 	});
 }
 
@@ -69,7 +71,8 @@ export default function visitIfBlock(
 	generator: DomGenerator,
 	block: Block,
 	state: State,
-	node: Node
+	node: Node,
+	elementStack: Node[]
 ) {
 	const name = generator.getUniqueName(`if_block`);
 	const anchor = node.needsAnchor
@@ -77,7 +80,7 @@ export default function visitIfBlock(
 		: (node.next && node.next._state.name) || 'null';
 	const params = block.params.join(', ');
 
-	const branches = getBranches(generator, block, state, node);
+	const branches = getBranches(generator, block, state, node, elementStack);
 
 	const hasElse = isElseBranch(branches[branches.length - 1]);
 	const if_name = hasElse ? '' : `if ( ${name} ) `;
diff --git a/src/generators/server-side-rendering/index.ts b/src/generators/server-side-rendering/index.ts
index 29cfccd67a54..ff18b0687888 100644
--- a/src/generators/server-side-rendering/index.ts
+++ b/src/generators/server-side-rendering/index.ts
@@ -1,6 +1,7 @@
 import deindent from '../../utils/deindent';
 import Generator from '../Generator';
 import Block from './Block';
+import preprocess from './preprocess';
 import visit from './visit';
 import { removeNode, removeObjectKey } from '../../utils/removeNode';
 import { Parsed, Node, CompileOptions } from '../../interfaces';
@@ -24,6 +25,10 @@ export class SsrGenerator extends Generator {
 		// in an SSR context, we don't need to include events, methods, oncreate or ondestroy
 		const { templateProperties, defaultExport } = this;
 
+		preprocess(this, parsed.html);
+
+		this.warnOnUnusedSelectors();
+
 		if (templateProperties.oncreate)
 			removeNode(
 				this.code,
diff --git a/src/generators/server-side-rendering/preprocess.ts b/src/generators/server-side-rendering/preprocess.ts
new file mode 100644
index 000000000000..c82fda9e9bc7
--- /dev/null
+++ b/src/generators/server-side-rendering/preprocess.ts
@@ -0,0 +1,90 @@
+import { SsrGenerator } from './index';
+import { Node } from '../../interfaces';
+
+function noop () {}
+
+function isElseIf(node: Node) {
+	return (
+		node && node.children.length === 1 && node.children[0].type === 'IfBlock'
+	);
+}
+
+const preprocessors = {
+	MustacheTag: noop,
+	RawMustacheTag: noop,
+	Text: noop,
+
+	IfBlock: (
+		generator: SsrGenerator,
+		node: Node,
+		elementStack: Node[]
+	) => {
+		function attachBlocks(node: Node) {
+			preprocessChildren(generator, node, elementStack);
+
+			if (isElseIf(node.else)) {
+				attachBlocks(node.else.children[0]);
+			} else if (node.else) {
+				preprocessChildren(
+					generator,
+					node.else,
+					elementStack
+				);
+			}
+		}
+
+		attachBlocks(node);
+	},
+
+	EachBlock: (
+		generator: SsrGenerator,
+		node: Node,
+		elementStack: Node[]
+	) => {
+		preprocessChildren(generator, node, elementStack);
+
+		if (node.else) {
+			preprocessChildren(
+				generator,
+				node.else,
+				elementStack
+			);
+		}
+	},
+
+	Element: (
+		generator: SsrGenerator,
+		node: Node,
+		elementStack: Node[]
+	) => {
+		const isComponent =
+			generator.components.has(node.name) || node.name === ':Self';
+
+		if (!isComponent) {
+			generator.applyCss(node, elementStack);
+		}
+
+		if (node.children.length) {
+			if (isComponent) {
+				preprocessChildren(generator, node, elementStack);
+			} else {
+				preprocessChildren(generator, node, elementStack.concat(node));
+			}
+		}
+	},
+};
+
+function preprocessChildren(
+	generator: SsrGenerator,
+	node: Node,
+	elementStack: Node[]
+) {
+	node.children.forEach((child: Node, i: number) => {
+		const preprocessor = preprocessors[child.type];
+		if (preprocessor) preprocessor(generator, child, elementStack);
+	});
+}
+
+export default function preprocess(generator: SsrGenerator, html: Node) {
+	preprocessChildren(generator, html, []);
+}
\ No newline at end of file
diff --git a/src/generators/server-side-rendering/visitors/Element.ts b/src/generators/server-side-rendering/visitors/Element.ts
index 3540bd12f70b..765e16ec8a7f 100644
--- a/src/generators/server-side-rendering/visitors/Element.ts
+++ b/src/generators/server-side-rendering/visitors/Element.ts
@@ -56,7 +56,7 @@ export default function visitElement(
 		}
 	});
 
-	if (generator.cssId && (!generator.cascade || generator.elementDepth === 0)) {
+	if (node._needsCssAttribute) {
 		openingTag += ` ${generator.cssId}`;
 	}
 
diff --git a/src/generators/shared/processCss.ts b/src/generators/shared/processCss.ts
index 8ea6021452ef..15719e7b8f72 100644
--- a/src/generators/shared/processCss.ts
+++ b/src/generators/shared/processCss.ts
@@ -1,4 +1,5 @@
 import MagicString from 'magic-string';
+import { groupSelectors, isGlobalSelector, walkRules } from '../../utils/css';
 import { Parsed, Node } from '../../interfaces';
 
 const commentsPattern = /\/\*[\s\S]*?\*\//g;
@@ -37,6 +38,22 @@ export default function processCss(
 
 	parsed.css.children.forEach(walkKeyframes);
 
+	function encapsulateBlock(block: Node[]) {
+		let i = block.length;
+		while (i--) {
+			const child = block[i];
+			if (child.type === 'PseudoElementSelector' || child.type === 'PseudoClassSelector') continue;
+
+			if (child.type === 'TypeSelector' && child.name === '*') {
+				code.overwrite(child.start, child.end, attr);
+			} else {
+				code.appendLeft(child.end, attr);
+			}
+
+			return;
+		}
+	}
+
 	function transform(rule: Node) {
 		rule.selector.children.forEach((selector: Node) => {
 			if (cascade) {
@@ -52,7 +69,7 @@ export default function processCss(
 
 				if (firstToken.type === 'TypeSelector') {
 					const insert = firstToken.end - offset;
-					const head = css.slice(start, insert);
+					const head = firstToken.name === '*' ? css.slice(firstToken.end - offset, insert) : css.slice(start, insert);
 					const tail = css.slice(insert, end);
 
 					transformed = `${head}${attr}${tail}, ${attr} ${selectorString}`;
@@ -65,37 +82,23 @@ export default function processCss(
 				let shouldTransform = true;
 				let c = selector.start;
 
-				selector.children.forEach((child: Node) => {
-					if (child.type === 'WhiteSpace' || child.type === 'Combinator') {
-						code.appendLeft(c, attr);
-						shouldTransform = true;
-						return;
-					}
+				// separate .foo > .bar > .baz into three separate blocks, so
+				// that we can transform only the first and last
+				let block: Node[] = [];
+				const blocks: Node[][] = groupSelectors(selector);
 
-					if (!shouldTransform) return;
-
-					if (child.type === 'PseudoClassSelector') {
-						// `:global(xyz)` > xyz
-						if (child.name === 'global') {
-							const first = child.children[0];
-							const last = child.children[child.children.length - 1];
-							code.remove(child.start, first.start).remove(last.end, child.end);
-						} else {
-							code.prependRight(c, attr);
-						}
-
-						shouldTransform = false;
-					} else if (child.type === 'PseudoElementSelector') {
-						code.prependRight(c, attr);
-						shouldTransform = false;
+				blocks.forEach((block: Node[], i) => {
+					if (i === 0 || i === blocks.length - 1) {
+						encapsulateBlock(blocks[i]);
 					}
 
-					c = child.end;
+					if (isGlobalSelector(block)) {
+						const selector = block[0];
+						const first = selector.children[0];
+						const last = selector.children[selector.children.length - 1];
+						code.remove(selector.start, first.start).remove(last.end, selector.end);
+					}
 				});
-
-				if (shouldTransform) {
-					code.appendLeft(c, attr);
-				}
 			}
 		});
 
@@ -116,22 +119,7 @@ export default function processCss(
 		});
 	}
 
-	function walk(node: Node) {
-		if (node.type === 'Rule') {
-			transform(node);
-		} else if (
-			node.type === 'Atrule' &&
-			node.name.toLowerCase() === 'keyframes'
-		) {
-			// these have already been processed
-		} else if (node.children) {
-			node.children.forEach(walk);
-		} else if (node.block) {
-			walk(node.block);
-		}
-	}
-
-	parsed.css.children.forEach(walk);
+	walkRules(parsed.css.children, transform);
 
 	// remove comments. TODO would be nice if this was exposed in css-tree
 	let match;
diff --git a/src/interfaces.ts b/src/interfaces.ts
index fbb745b7b8e1..78fc8730b985 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -26,9 +26,11 @@ export interface Parsed {
 }
 
 export interface Warning {
-	loc?: { line: number; column: number; pos: number };
+	loc?: { line: number; column: number; pos?: number };
+	pos?: number;
 	message: string;
 	filename?: string;
+	frame?: string;
 	toString: () => string;
 }
 
diff --git a/src/utils/css.ts b/src/utils/css.ts
new file mode 100644
index 000000000000..ac78bdd96a0e
--- /dev/null
+++ b/src/utils/css.ts
@@ -0,0 +1,33 @@
+import { Node } from '../interfaces';
+
+export function isGlobalSelector(block: Node[]) {
+	return block.length === 1 && block[0].type === 'PseudoClassSelector' && block[0].name === 'global';
+}
+
+export function groupSelectors(selector: Node) {
+	let block: Node[] = [];
+	const blocks: Node[][] = [block];
+
+	selector.children.forEach((child: Node) => {
+		if (child.type === 'WhiteSpace' || child.type === 'Combinator') {
+			block = [];
+			blocks.push(block);
+		} else {
+			block.push(child);
+		}
+	});
+
+	return blocks;
+}
+
+export function walkRules(nodes: Node[], callback: (node: Node) => void) {
+	nodes.forEach((node: Node) => {
+		if (node.type === 'Rule') {
+			callback(node);
+		} else if (node.type === 'Atrule') {
+			if (node.name === 'media' || node.name === 'supports' || node.name === 'document') {
+				walkRules(node.block.children, callback);
+			}
+		}
+	});
+}
\ No newline at end of file
diff --git a/src/validate/css/index.ts b/src/validate/css/index.ts
new file mode 100644
index 000000000000..6251f59fb0a3
--- /dev/null
+++ b/src/validate/css/index.ts
@@ -0,0 +1,44 @@
+import { groupSelectors, isGlobalSelector, walkRules } from '../../utils/css';
+import { Validator } from '../index';
+import { Node } from '../../interfaces';
+
+export default function validateCss(validator: Validator, css: Node) {
+	walkRules(css.children, rule => {
+		rule.selector.children.forEach(validateSelector);
+	});
+
+	function validateSelector(selector: Node) {
+		const blocks: Node[][] = groupSelectors(selector);
+
+		blocks.forEach((block, i) => {
+			if (block.find((part: Node) => part.type === 'PseudoClassSelector' && part.name === 'global')) {
+				// check that :global(...) is by itself
+				if (block.length !== 1) {
+					validator.error(`:global(...) cannot be mixed with non-global selectors`, block[0].start);
+				}
+
+				// check that :global(...) isn't sandwiched by other selectors
+				// if (i > 0 && i < blocks.length - 1) {
+				// 	validator.error(`:global(...) can be at the start or end of a selector sequence, but not in the middle`, block[0].start);
+				// }
+			}
+		});
+
+		let start = 0;
+		let end = blocks.length;
+
+		for (; start < end; start += 1) {
+			if (!isGlobalSelector(blocks[start])) break;
+		}
+
+		for (; end > start; end -= 1) {
+			if (!isGlobalSelector(blocks[end - 1])) break;
+		}
+
+		for (let i = start; i < end; i += 1) {
+			if (isGlobalSelector(blocks[i])) {
+				validator.error(`:global(...) can be at the start or end of a selector sequence, but not in the middle`, blocks[i][0].start);
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/validate/index.ts b/src/validate/index.ts
index a395eb83d856..62cb9e614d11 100644
--- a/src/validate/index.ts
+++ b/src/validate/index.ts
@@ -1,4 +1,5 @@
 import validateJs from './js/index';
+import validateCss from './css/index';
 import validateHtml from './html/index';
 import { getLocator, Location } from 'locate-character';
 import getCodeFrame from '../utils/getCodeFrame';
@@ -34,9 +35,9 @@ export class Validator {
 
 	constructor(parsed: Parsed, source: string, options: CompileOptions) {
 		this.source = source;
-		this.filename = options !== undefined ? options.filename : undefined;
+		this.filename = options.filename;
 
-		this.onwarn = options !== undefined ? options.onwarn : undefined;
+		this.onwarn = options.onwarn;
 
 		this.namespace = null;
 		this.defaultExport = null;
@@ -101,6 +102,10 @@ export default function validate(
 			validateJs(validator, parsed.js);
 		}
 
+		if (parsed.css) {
+			validateCss(validator, parsed.css);
+		}
+
 		if (parsed.html) {
 			validateHtml(validator, parsed.html);
 		}
diff --git a/test/css/index.js b/test/css/index.js
index 51cf1b4aba99..221f67973908 100644
--- a/test/css/index.js
+++ b/test/css/index.js
@@ -1,16 +1,24 @@
 import assert from "assert";
 import * as fs from "fs";
-import { svelte } from "../helpers.js";
+import { env, normalizeHtml, svelte } from "../helpers.js";
 
 function tryRequire(file) {
 	try {
-		return require(file).default;
+		const mod = require(file);
+		return mod.default || mod;
 	} catch (err) {
 		if (err.code !== "MODULE_NOT_FOUND") throw err;
 		return null;
 	}
 }
 
+function normalizeWarning(warning) {
+	warning.frame = warning.frame.replace(/^\n/, '').replace(/^\t+/gm, '');
+	delete warning.filename;
+	delete warning.toString;
+	return warning;
+}
+
 describe("css", () => {
 	fs.readdirSync("test/css/samples").forEach(dir => {
 		if (dir[0] === ".") return;
@@ -28,14 +36,74 @@ describe("css", () => {
 				.readFileSync(`test/css/samples/${dir}/input.html`, "utf-8")
 				.replace(/\s+$/, "");
 
-			const actual = svelte.compile(input, config).css;
-			fs.writeFileSync(`test/css/samples/${dir}/_actual.css`, actual);
-			const expected = fs.readFileSync(
-				`test/css/samples/${dir}/expected.css`,
-				"utf-8"
-			);
+			const expectedWarnings = (config.warnings || []).map(normalizeWarning);
+			const domWarnings = [];
+			const ssrWarnings = [];
+
+			const dom = svelte.compile(input, Object.assign(config, {
+				format: 'iife',
+				name: 'SvelteComponent',
+				onwarn: warning => {
+					domWarnings.push(warning);
+				}
+			}));
+
+			const ssr = svelte.compile(input, Object.assign(config, {
+				format: 'iife',
+				generate: 'ssr',
+				name: 'SvelteComponent',
+				onwarn: warning => {
+					ssrWarnings.push(warning);
+				}
+			}));
+
+			assert.equal(dom.css, ssr.css);
+
+			assert.deepEqual(domWarnings.map(normalizeWarning), ssrWarnings.map(normalizeWarning));
+			assert.deepEqual(domWarnings.map(normalizeWarning), expectedWarnings);
+
+			fs.writeFileSync(`test/css/samples/${dir}/_actual.css`, dom.css);
+			const expected = {
+				html: read(`test/css/samples/${dir}/expected.html`),
+				css: read(`test/css/samples/${dir}/expected.css`)
+			};
+
+			assert.equal(dom.css.trim(), expected.css.trim());
+
+			// verify that the right elements have scoping selectors
+			if (expected.html !== null) {
+				return env().then(window => {
+					const Component = eval(`(function () { ${dom.code}; return SvelteComponent; }())`);
+					const target = window.document.querySelector("main");
 
-			assert.equal(actual.trim(), expected.trim());
+					new Component({ target, data: config.data });
+					const html = target.innerHTML;
+
+					fs.writeFileSync(`test/css/samples/${dir}/_actual.html`, html);
+
+					// dom
+					assert.equal(
+						normalizeHtml(window, html),
+						normalizeHtml(window, expected.html)
+					);
+
+					// ssr
+					const component = eval(`(function () { ${ssr.code}; return SvelteComponent; }())`);
+
+					assert.equal(
+						normalizeHtml(window, component.render(config.data)),
+						normalizeHtml(window, expected.html)
+					);
+				});
+			}
 		});
 	});
 });
+
+function read(file) {
+	try {
+		return fs.readFileSync(file, 'utf-8');
+	} catch(err) {
+		return null;
+	}
+}
\ No newline at end of file
diff --git a/test/css/samples/cascade-false-universal-selector/_config.js b/test/css/samples/cascade-false-universal-selector/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/cascade-false-universal-selector/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/cascade-false-universal-selector/expected.css b/test/css/samples/cascade-false-universal-selector/expected.css
new file mode 100644
index 000000000000..bb9155feb061
--- /dev/null
+++ b/test/css/samples/cascade-false-universal-selector/expected.css
@@ -0,0 +1,4 @@
+
+	[svelte-2950902288] {
+		color: red;
+	}
diff --git a/test/css/samples/cascade-false-universal-selector/expected.html b/test/css/samples/cascade-false-universal-selector/expected.html
new file mode 100644
index 000000000000..732e063d51d3
--- /dev/null
+++ b/test/css/samples/cascade-false-universal-selector/expected.html
@@ -0,0 +1 @@
+<div svelte-2950902288=""></div>
\ No newline at end of file
diff --git a/test/css/samples/cascade-false-universal-selector/input.html b/test/css/samples/cascade-false-universal-selector/input.html
new file mode 100644
index 000000000000..36a65e23e6fa
--- /dev/null
+++ b/test/css/samples/cascade-false-universal-selector/input.html
@@ -0,0 +1,7 @@
+<div></div>
+
+<style>
+	* {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-contains/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-contains/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/expected.css
new file mode 100644
index 000000000000..b48dfbe85a86
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo*='bar'][svelte-4224841812] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-contains/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/expected.html
new file mode 100644
index 000000000000..22a45b853e2b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/expected.html
@@ -0,0 +1,2 @@
+<div><p svelte-4224841812="" data-foo="foobarbaz">this is styled</p>
+	<p data-foo="fooBARbaz">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-contains/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/input.html
new file mode 100644
index 000000000000..ea0d54fe6754
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-contains/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='foobarbaz'>this is styled</p>
+	<p data-foo='fooBARbaz'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo*='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/expected.css
new file mode 100644
index 000000000000..d20a6b98bf10
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo='bar' i][svelte-4191913977] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/expected.html
new file mode 100644
index 000000000000..1d65033d3e0a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/expected.html
@@ -0,0 +1,2 @@
+<div><p svelte-4191913977="" data-foo="BAR">this is styled</p>
+	<p data-foo="BAZ">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/input.html
new file mode 100644
index 000000000000..e80da7b707e1
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-case-insensitive/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='BAR'>this is styled</p>
+	<p data-foo='BAZ'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo='bar' i] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/_config.js
new file mode 100644
index 000000000000..32cdf8cb7919
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/_config.js
@@ -0,0 +1,6 @@
+export default {
+	cascade: false,
+	data: {
+		dynamic: 'whatever'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/expected.css
new file mode 100644
index 000000000000..26fdc211a078
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo='bar'][svelte-1339732946] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/expected.html
new file mode 100644
index 000000000000..e27985b20d1c
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/expected.html
@@ -0,0 +1,2 @@
+<div><p svelte-1339732946="" data-foo="whatever">this is styled</p>
+	<p data-foo="baz">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/input.html
new file mode 100644
index 000000000000..7ddd680b27c3
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals-dynamic/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='{{dynamic}}'>this is styled</p>
+	<p data-foo='baz'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/expected.css
new file mode 100644
index 000000000000..4a2cb3428e7b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo='bar'][svelte-2543760126] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/expected.html
new file mode 100644
index 000000000000..6dcb8cfaa365
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/expected.html
@@ -0,0 +1,2 @@
+<div><p svelte-2543760126="" data-foo="bar">this is styled</p>
+	<p data-foo="baz">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-equals/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/input.html
new file mode 100644
index 000000000000..28e31604f8a3
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-equals/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='bar'>this is styled</p>
+	<p data-foo='baz'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/expected.css
new file mode 100644
index 000000000000..8b57a24cd9d3
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo|='bar'][svelte-1225676040] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/expected.html
new file mode 100644
index 000000000000..1ba93cd6e50b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/expected.html
@@ -0,0 +1,3 @@
+<div><p svelte-1225676040="" data-foo="bar">this is styled</p>
+	<p svelte-1225676040="" data-foo="bar-baz">this is styled</p>
+	<p data-foo="baz-bar">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/input.html
new file mode 100644
index 000000000000..c7a8b598ecea
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-pipe-equals/input.html
@@ -0,0 +1,11 @@
+<div>
+	<p data-foo='bar'>this is styled</p>
+	<p data-foo='bar-baz'>this is styled</p>
+	<p data-foo='baz-bar'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo|='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/expected.css
new file mode 100644
index 000000000000..232c462c4b04
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo^='bar'][svelte-3106767242] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/expected.html
new file mode 100644
index 000000000000..267528a5168d
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/expected.html
@@ -0,0 +1,2 @@
+<div><p svelte-3106767242="" data-foo="barbaz">this is styled</p>
+	<p data-foo="bazbar">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/input.html
new file mode 100644
index 000000000000..91daf582fd94
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-prefix/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='barbaz'>this is styled</p>
+	<p data-foo='bazbar'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo^='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/expected.css
new file mode 100644
index 000000000000..832f50cf3be7
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo$='bar'][svelte-207782622] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/expected.html
new file mode 100644
index 000000000000..00bf78a6ca82
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/expected.html
@@ -0,0 +1,2 @@
+<div><p data-foo="barbaz">this is unstyled</p>
+	<p svelte-207782622="" data-foo="bazbar">this is styled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/input.html
new file mode 100644
index 000000000000..641d776c6c38
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-suffix/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='barbaz'>this is unstyled</p>
+	<p data-foo='bazbar'>this is styled</p>
+</div>
+
+<style>
+	[data-foo$='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/expected.css
new file mode 100644
index 000000000000..20cf2fd9e380
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/expected.css
@@ -0,0 +1,4 @@
+
+	[data-foo~='bar'][svelte-1786044856] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/expected.html
new file mode 100644
index 000000000000..aef480d8ef24
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/expected.html
@@ -0,0 +1,2 @@
+<div><p svelte-1786044856="" data-foo="qux bar">this is styled</p>
+	<p data-foo="qux baz">this is unstyled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/input.html
new file mode 100644
index 000000000000..026d7d6ed25b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector-word-equals/input.html
@@ -0,0 +1,10 @@
+<div>
+	<p data-foo='qux bar'>this is styled</p>
+	<p data-foo='qux baz'>this is unstyled</p>
+</div>
+
+<style>
+	[data-foo~='bar'] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector/_config.js b/test/css/samples/omit-scoping-attribute-attribute-selector/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector/expected.css b/test/css/samples/omit-scoping-attribute-attribute-selector/expected.css
new file mode 100644
index 000000000000..662e453d8382
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector/expected.css
@@ -0,0 +1,4 @@
+
+	[autoplay][svelte-240005720] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector/expected.html b/test/css/samples/omit-scoping-attribute-attribute-selector/expected.html
new file mode 100644
index 000000000000..254afb2a46ed
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector/expected.html
@@ -0,0 +1,2 @@
+<div><video svelte-240005720 autoplay></video>
+	<video></video></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-attribute-selector/input.html b/test/css/samples/omit-scoping-attribute-attribute-selector/input.html
new file mode 100644
index 000000000000..6f4549ead8d8
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-attribute-selector/input.html
@@ -0,0 +1,10 @@
+<div>
+	<video autoplay></video>
+	<video></video>
+</div>
+
+<style>
+	[autoplay] {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-class-dynamic/_config.js b/test/css/samples/omit-scoping-attribute-class-dynamic/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-dynamic/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-class-dynamic/expected.css b/test/css/samples/omit-scoping-attribute-class-dynamic/expected.css
new file mode 100644
index 000000000000..45b763d4de37
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-dynamic/expected.css
@@ -0,0 +1,4 @@
+
+	.foo[svelte-2643270928] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-class-dynamic/expected.html b/test/css/samples/omit-scoping-attribute-class-dynamic/expected.html
new file mode 100644
index 000000000000..a51f22d968a2
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-dynamic/expected.html
@@ -0,0 +1,2 @@
+<p svelte-2643270928="" class="whatever">this is styled</p>
+<p class="bar">this is unstyled</p>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-class-dynamic/input.html b/test/css/samples/omit-scoping-attribute-class-dynamic/input.html
new file mode 100644
index 000000000000..1ef2a1796aa7
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-dynamic/input.html
@@ -0,0 +1,18 @@
+<p class='{{unknown}}'>this is styled</p>
+<p class='bar'>this is unstyled</p>
+
+<style>
+	.foo {
+		color: red;
+	}
+</style>
+
+<script>
+	export default {
+		data () {
+			return {
+				unknown: 'whatever'
+			};
+		}
+	};
+</script>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-class-static/_config.js b/test/css/samples/omit-scoping-attribute-class-static/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-static/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-class-static/expected.css b/test/css/samples/omit-scoping-attribute-class-static/expected.css
new file mode 100644
index 000000000000..bf4e3cb73c45
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-static/expected.css
@@ -0,0 +1,4 @@
+
+	.foo[svelte-633959357] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-class-static/expected.html b/test/css/samples/omit-scoping-attribute-class-static/expected.html
new file mode 100644
index 000000000000..b972aa4cb195
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-static/expected.html
@@ -0,0 +1,2 @@
+<p svelte-633959357="" class="foo">this is styled</p>
+<p class="bar">this is unstyled</p>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-class-static/input.html b/test/css/samples/omit-scoping-attribute-class-static/input.html
new file mode 100644
index 000000000000..6b877fa13e18
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-class-static/input.html
@@ -0,0 +1,8 @@
+<p class='foo'>this is styled</p>
+<p class='bar'>this is unstyled</p>
+
+<style>
+	.foo {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/_config.js b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/_config.js
new file mode 100644
index 000000000000..0371e65c7e35
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/_config.js
@@ -0,0 +1,7 @@
+export default {
+	cascade: false,
+
+	data: {
+		raw: '<p>raw</p>'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/expected.css b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/expected.css
new file mode 100644
index 000000000000..5b0fe980e66e
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/expected.css
@@ -0,0 +1,4 @@
+
+	.foo[svelte-2122726581] .bar {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/expected.html b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/expected.html
new file mode 100644
index 000000000000..008c01737416
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/expected.html
@@ -0,0 +1 @@
+<div svelte-2122726581="" class="foo"></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/input.html b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/input.html
new file mode 100644
index 000000000000..c2f6057255d0
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-class/input.html
@@ -0,0 +1,9 @@
+<div class='foo'>
+	<!-- html injected somehow -->
+</div>
+
+<style>
+	.foo :global(.bar) {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/_config.js b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/_config.js
new file mode 100644
index 000000000000..0371e65c7e35
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/_config.js
@@ -0,0 +1,7 @@
+export default {
+	cascade: false,
+
+	data: {
+		raw: '<p>raw</p>'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/expected.css b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/expected.css
new file mode 100644
index 000000000000..d09033651f46
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/expected.css
@@ -0,0 +1,4 @@
+
+	div[svelte-3386191472] > p > em {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/expected.html b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/expected.html
new file mode 100644
index 000000000000..db137321742e
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/expected.html
@@ -0,0 +1 @@
+<div svelte-3386191472=""></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/input.html b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/input.html
new file mode 100644
index 000000000000..85baf01a2dc6
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner-multiple/input.html
@@ -0,0 +1,9 @@
+<div>
+	<!-- html injected somehow -->
+</div>
+
+<style>
+	div > :global(p) > :global(em) {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner/_config.js b/test/css/samples/omit-scoping-attribute-descendant-global-inner/_config.js
new file mode 100644
index 000000000000..0371e65c7e35
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner/_config.js
@@ -0,0 +1,7 @@
+export default {
+	cascade: false,
+
+	data: {
+		raw: '<p>raw</p>'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner/expected.css b/test/css/samples/omit-scoping-attribute-descendant-global-inner/expected.css
new file mode 100644
index 000000000000..67a7fbed8682
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner/expected.css
@@ -0,0 +1,4 @@
+
+	div[svelte-3744486606] > p {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner/expected.html b/test/css/samples/omit-scoping-attribute-descendant-global-inner/expected.html
new file mode 100644
index 000000000000..4511b7222133
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner/expected.html
@@ -0,0 +1 @@
+<div svelte-3744486606=""></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-inner/input.html b/test/css/samples/omit-scoping-attribute-descendant-global-inner/input.html
new file mode 100644
index 000000000000..bad6794f252f
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-inner/input.html
@@ -0,0 +1,9 @@
+<div>
+	<!-- html injected somehow -->
+</div>
+
+<style>
+	div > :global(p) {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/_config.js b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/_config.js
new file mode 100644
index 000000000000..0371e65c7e35
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/_config.js
@@ -0,0 +1,7 @@
+export default {
+	cascade: false,
+
+	data: {
+		raw: '<p>raw</p>'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/expected.css b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/expected.css
new file mode 100644
index 000000000000..9137c5bd8d00
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/expected.css
@@ -0,0 +1,4 @@
+
+	div > section > p[svelte-3390623146] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/expected.html b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/expected.html
new file mode 100644
index 000000000000..35cfecee4fb5
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/expected.html
@@ -0,0 +1 @@
+<p svelte-3390623146="">this may or may not be styled</p>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/input.html b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/input.html
new file mode 100644
index 000000000000..57e227284c6a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer-multiple/input.html
@@ -0,0 +1,7 @@
+<p>this may or may not be styled</p>
+
+<style>
+	:global(div) > :global(section) > p {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer/_config.js b/test/css/samples/omit-scoping-attribute-descendant-global-outer/_config.js
new file mode 100644
index 000000000000..0371e65c7e35
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer/_config.js
@@ -0,0 +1,7 @@
+export default {
+	cascade: false,
+
+	data: {
+		raw: '<p>raw</p>'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer/expected.css b/test/css/samples/omit-scoping-attribute-descendant-global-outer/expected.css
new file mode 100644
index 000000000000..46c00c646dfd
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer/expected.css
@@ -0,0 +1,4 @@
+
+	div > p[svelte-794545435] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer/expected.html b/test/css/samples/omit-scoping-attribute-descendant-global-outer/expected.html
new file mode 100644
index 000000000000..5c3c80ea93b8
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer/expected.html
@@ -0,0 +1 @@
+<p svelte-794545435="">this may or may not be styled</p>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant-global-outer/input.html b/test/css/samples/omit-scoping-attribute-descendant-global-outer/input.html
new file mode 100644
index 000000000000..e5fb3ba144f9
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant-global-outer/input.html
@@ -0,0 +1,7 @@
+<p>this may or may not be styled</p>
+
+<style>
+	:global(div) > p {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant/_config.js b/test/css/samples/omit-scoping-attribute-descendant/_config.js
new file mode 100644
index 000000000000..0d56c7ba8c09
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant/_config.js
@@ -0,0 +1,19 @@
+export default {
+	cascade: false,
+
+	warnings: [{
+		message: 'Unused CSS selector',
+		loc: {
+			line: 8,
+			column: 1
+		},
+		pos: 74,
+		frame: `
+			 6: 
+			 7: <style>
+			 8:   div > p {
+			      ^
+			 9:     color: red;
+			10:   }`
+	}]
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant/expected.css b/test/css/samples/omit-scoping-attribute-descendant/expected.css
new file mode 100644
index 000000000000..548ef810ef97
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant/expected.css
@@ -0,0 +1,4 @@
+
+	div[svelte-2557028325] > p[svelte-2557028325] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-descendant/expected.html b/test/css/samples/omit-scoping-attribute-descendant/expected.html
new file mode 100644
index 000000000000..c3cd49d71e6b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant/expected.html
@@ -0,0 +1 @@
+<div><section><p>this is not styled</p></section></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-descendant/input.html b/test/css/samples/omit-scoping-attribute-descendant/input.html
new file mode 100644
index 000000000000..8af2cc4dd117
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-descendant/input.html
@@ -0,0 +1,11 @@
+<div>
+	<section>
+		<p>this is not styled</p>
+	</section>
+</div>
+
+<style>
+	div > p {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-global/_config.js b/test/css/samples/omit-scoping-attribute-global/_config.js
new file mode 100644
index 000000000000..0371e65c7e35
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-global/_config.js
@@ -0,0 +1,7 @@
+export default {
+	cascade: false,
+
+	data: {
+		raw: '<p>raw</p>'
+	}
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-global/expected.css b/test/css/samples/omit-scoping-attribute-global/expected.css
new file mode 100644
index 000000000000..be3405979388
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-global/expected.css
@@ -0,0 +1,4 @@
+
+	div {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-global/expected.html b/test/css/samples/omit-scoping-attribute-global/expected.html
new file mode 100644
index 000000000000..281c6866c375
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-global/expected.html
@@ -0,0 +1 @@
+<div></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-global/input.html b/test/css/samples/omit-scoping-attribute-global/input.html
new file mode 100644
index 000000000000..a85bfa0bb334
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-global/input.html
@@ -0,0 +1,7 @@
+<div></div>
+
+<style>
+	:global(div) {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-id/_config.js b/test/css/samples/omit-scoping-attribute-id/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-id/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-id/expected.css b/test/css/samples/omit-scoping-attribute-id/expected.css
new file mode 100644
index 000000000000..d62cda1725ce
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-id/expected.css
@@ -0,0 +1,4 @@
+
+	#foo[svelte-2727164615] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-id/expected.html b/test/css/samples/omit-scoping-attribute-id/expected.html
new file mode 100644
index 000000000000..f9e629de5673
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-id/expected.html
@@ -0,0 +1,2 @@
+<div svelte-2727164615="" id="foo"></div>
+<div id="bar"></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-id/input.html b/test/css/samples/omit-scoping-attribute-id/input.html
new file mode 100644
index 000000000000..9db4995a028b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-id/input.html
@@ -0,0 +1,8 @@
+<div id='foo'></div>
+<div id='bar'></div>
+
+<style>
+	#foo {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-whitespace-multiple/_config.js b/test/css/samples/omit-scoping-attribute-whitespace-multiple/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace-multiple/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.css b/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.css
new file mode 100644
index 000000000000..590f54700608
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.css
@@ -0,0 +1,4 @@
+
+	div[svelte-4032668709] section p[svelte-4032668709] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.html b/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.html
new file mode 100644
index 000000000000..7a3dea14316b
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace-multiple/expected.html
@@ -0,0 +1 @@
+<div svelte-4032668709=""><section><p svelte-4032668709="">this is styled</p></section></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-whitespace-multiple/input.html b/test/css/samples/omit-scoping-attribute-whitespace-multiple/input.html
new file mode 100644
index 000000000000..a3e4b4136a88
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace-multiple/input.html
@@ -0,0 +1,11 @@
+<div>
+	<section>
+		<p>this is styled</p>
+	</section>
+</div>
+
+<style>
+	div section p {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-whitespace/_config.js b/test/css/samples/omit-scoping-attribute-whitespace/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-whitespace/expected.css b/test/css/samples/omit-scoping-attribute-whitespace/expected.css
new file mode 100644
index 000000000000..fedf7985e148
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace/expected.css
@@ -0,0 +1,4 @@
+
+	div[svelte-4240344240] p[svelte-4240344240] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute-whitespace/expected.html b/test/css/samples/omit-scoping-attribute-whitespace/expected.html
new file mode 100644
index 000000000000..06092e315c54
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace/expected.html
@@ -0,0 +1 @@
+<div svelte-4240344240=""><section><p svelte-4240344240="">this is styled</p></section></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute-whitespace/input.html b/test/css/samples/omit-scoping-attribute-whitespace/input.html
new file mode 100644
index 000000000000..6d00e912676c
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute-whitespace/input.html
@@ -0,0 +1,11 @@
+<div>
+	<section>
+		<p>this is styled</p>
+	</section>
+</div>
+
+<style>
+	div p {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute/_config.js b/test/css/samples/omit-scoping-attribute/_config.js
new file mode 100644
index 000000000000..b37866f9b61a
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute/_config.js
@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute/expected.css b/test/css/samples/omit-scoping-attribute/expected.css
new file mode 100644
index 000000000000..f8adbd21a705
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute/expected.css
@@ -0,0 +1,4 @@
+
+	p[svelte-1997768937] {
+		color: red;
+	}
diff --git a/test/css/samples/omit-scoping-attribute/expected.html b/test/css/samples/omit-scoping-attribute/expected.html
new file mode 100644
index 000000000000..580168ced2e7
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute/expected.html
@@ -0,0 +1 @@
+<div><p svelte-1997768937="">this is styled</p></div>
\ No newline at end of file
diff --git a/test/css/samples/omit-scoping-attribute/input.html b/test/css/samples/omit-scoping-attribute/input.html
new file mode 100644
index 000000000000..69251dc236fb
--- /dev/null
+++ b/test/css/samples/omit-scoping-attribute/input.html
@@ -0,0 +1,9 @@
+<div>
+	<p>this is styled</p>
+</div>
+
+<style>
+	p {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/universal-selector/expected.css b/test/css/samples/universal-selector/expected.css
new file mode 100644
index 000000000000..53f57d90839c
--- /dev/null
+++ b/test/css/samples/universal-selector/expected.css
@@ -0,0 +1,4 @@
+
+	[svelte-2950902288], [svelte-2950902288] * {
+		color: red;
+	}
diff --git a/test/css/samples/universal-selector/input.html b/test/css/samples/universal-selector/input.html
new file mode 100644
index 000000000000..36a65e23e6fa
--- /dev/null
+++ b/test/css/samples/universal-selector/input.html
@@ -0,0 +1,7 @@
+<div></div>
+
+<style>
+	* {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/unused-selector/_config.js b/test/css/samples/unused-selector/_config.js
new file mode 100644
index 000000000000..48504c996d72
--- /dev/null
+++ b/test/css/samples/unused-selector/_config.js
@@ -0,0 +1,20 @@
+export default {
+	cascade: false,
+
+	warnings: [{
+		filename: "SvelteComponent.html",
+		message: "Unused CSS selector",
+		loc: {
+			line: 8,
+			column: 1
+		},
+		pos: 60,
+		frame: `
+			 6:   }
+			 7: 
+			 8:   .bar {
+			      ^
+			 9:     color: blue;
+			10:   }`
+	}]
+};
\ No newline at end of file
diff --git a/test/css/samples/unused-selector/expected.css b/test/css/samples/unused-selector/expected.css
new file mode 100644
index 000000000000..76559bfb61af
--- /dev/null
+++ b/test/css/samples/unused-selector/expected.css
@@ -0,0 +1,8 @@
+
+	.foo[svelte-698347462] {
+		color: red;
+	}
+
+	.bar[svelte-698347462] {
+		color: blue;
+	}
diff --git a/test/css/samples/unused-selector/expected.html b/test/css/samples/unused-selector/expected.html
new file mode 100644
index 000000000000..083a321ea7ad
--- /dev/null
+++ b/test/css/samples/unused-selector/expected.html
@@ -0,0 +1 @@
+<div svelte-698347462="" class="foo"></div>
\ No newline at end of file
diff --git a/test/css/samples/unused-selector/input.html b/test/css/samples/unused-selector/input.html
new file mode 100644
index 000000000000..1d62e3a67577
--- /dev/null
+++ b/test/css/samples/unused-selector/input.html
@@ -0,0 +1,11 @@
+<div class='foo'></div>
+
+<style>
+	.foo {
+		color: red;
+	}
+
+	.bar {
+		color: blue;
+	}
+</style>
\ No newline at end of file
diff --git a/test/css/samples/unused-selector/warnings.json b/test/css/samples/unused-selector/warnings.json
new file mode 100644
index 000000000000..6d6c3f5deba2
--- /dev/null
+++ b/test/css/samples/unused-selector/warnings.json
@@ -0,0 +1,10 @@
+[{
+	"filename": "SvelteComponent.html",
+	"message": "Unused CSS selector",
+	"loc": {
+		"line": 8,
+		"column": 1
+	},
+	"pos": 61,
+	"frame": " 6:   }\n 7: \n 8:   .bar {\n      ^\n 9:     color: blue;\n10:   }"
+}]
\ No newline at end of file
diff --git a/test/helpers.js b/test/helpers.js
index 8d9cd3a660e7..8087b173e4ef 100644
--- a/test/helpers.js
+++ b/test/helpers.js
@@ -69,6 +69,20 @@ export function env() {
 function cleanChildren(node) {
 	let previous = null;
 
+	// sort attributes
+	const attributes = Array.from(node.attributes).sort((a, b) => {
+		return a.name < b.name ? -1 : 1;
+	});
+
+	attributes.forEach(attr => {
+		node.removeAttribute(attr.name);
+	});
+
+	attributes.forEach(attr => {
+		node.setAttribute(attr.name, attr.value);
+	});
+
+	// recurse
 	[...node.childNodes].forEach(child => {
 		if (child.nodeType === 8) {
 			// comment
@@ -114,22 +128,23 @@ function cleanChildren(node) {
 	}
 }
 
+export function normalizeHtml(window, html) {
+	const node = window.document.createElement('div');
+	node.innerHTML = html
+		.replace(/>[\s\r\n]+</g, '><')
+		.trim();
+	cleanChildren(node, '');
+	return node.innerHTML;
+}
+
 export function setupHtmlEqual() {
 	return env().then(window => {
 		assert.htmlEqual = (actual, expected, message) => {
-			window.document.body.innerHTML = actual
-				.replace(/>[\s\r\n]+</g, '><')
-				.trim();
-			cleanChildren(window.document.body, '');
-			actual = window.document.body.innerHTML;
-
-			window.document.body.innerHTML = expected
-				.replace(/>[\s\r\n]+</g, '><')
-				.trim();
-			cleanChildren(window.document.body, '');
-			expected = window.document.body.innerHTML;
-
-			assert.deepEqual(actual, expected, message);
+			assert.deepEqual(
+				normalizeHtml(window, actual),
+				normalizeHtml(window, expected),
+				message
+			);
 		};
 	});
 }
diff --git a/test/validator/samples/css-invalid-global-placement/errors.json b/test/validator/samples/css-invalid-global-placement/errors.json
new file mode 100644
index 000000000000..a2b899417510
--- /dev/null
+++ b/test/validator/samples/css-invalid-global-placement/errors.json
@@ -0,0 +1,8 @@
+[{
+	"message": ":global(...) can be at the start or end of a selector sequence, but not in the middle",
+	"loc": {
+		"line": 2,
+		"column": 6
+	},
+	"pos": 14
+}]
\ No newline at end of file
diff --git a/test/validator/samples/css-invalid-global-placement/input.html b/test/validator/samples/css-invalid-global-placement/input.html
new file mode 100644
index 000000000000..33da3499b26f
--- /dev/null
+++ b/test/validator/samples/css-invalid-global-placement/input.html
@@ -0,0 +1,5 @@
+<style>
+	.foo :global(.bar) .baz {
+		color: red;
+	}
+</style>
\ No newline at end of file
diff --git a/test/validator/samples/css-invalid-global/errors.json b/test/validator/samples/css-invalid-global/errors.json
new file mode 100644
index 000000000000..8aa138e3f2f2
--- /dev/null
+++ b/test/validator/samples/css-invalid-global/errors.json
@@ -0,0 +1,8 @@
+[{
+	"message": ":global(...) cannot be mixed with non-global selectors",
+	"loc": {
+		"line": 2,
+		"column": 1
+	},
+	"pos": 9
+}]
\ No newline at end of file
diff --git a/test/validator/samples/css-invalid-global/input.html b/test/validator/samples/css-invalid-global/input.html
new file mode 100644
index 000000000000..5d325a4cd18f
--- /dev/null
+++ b/test/validator/samples/css-invalid-global/input.html
@@ -0,0 +1,5 @@
+<style>
+	:global(.foo).bar {
+		color: red;
+	}
+</style>
\ No newline at end of file