diff --git a/lib/parse.js b/lib/parse.js
index c0c5dfa..9841107 100644
--- a/lib/parse.js
+++ b/lib/parse.js
@@ -169,7 +169,7 @@ var parser = new Parser({
 		"/\\*([\\s\\S]*?)\\*/": commentMatch,
 		"\\.((?:\\\\.|[A-Za-z_\\-])(?:\\\\.|[A-Za-z_\\-0-9])*)": typeMatch("class"),
 		"#((?:\\\\.|[A-Za-z_\\-])(?:\\\\.|[A-Za-z_\\-0-9])*)": typeMatch("id"),
-		":(not|has|local|global)\\((\\s*)": nestedPseudoClassStartMatch,
+		":(not|matches|has|local|global)\\((\\s*)": nestedPseudoClassStartMatch,
 		":((?:\\\\.|[A-Za-z_\\-0-9])+)\\(": pseudoClassStartMatch,
 		":((?:\\\\.|[A-Za-z_\\-0-9])+)": typeMatch("pseudo-class"),
 		"::((?:\\\\.|[A-Za-z_\\-0-9])+)": typeMatch("pseudo-element"),
@@ -179,7 +179,7 @@ var parser = new Parser({
 		"((?:\\\\.|[A-Za-z_\\-0-9])*\\|)?((?:\\\\.|[A-Za-z_\\-])(?:\\\\.|[A-Za-z_\\-0-9])*)": elementMatch,
 		"\\[([^\\]]+)\\]": attributeMatch,
 		"(\\s*)\\)": nestedEnd,
-		"(\\s*)([>+~])(\\s*)": operatorMatch,
+		"(\\s*)((?:\\|\\|)|(?:>>)|[>+~])(\\s*)": operatorMatch,
 		"(\\s*),(\\s*)": nextSelectorMatch,
 		"\\s+$": irrelevantSpacingEndMatch,
 		"^\\s+": irrelevantSpacingStartMatch,
diff --git a/lib/stringify.js b/lib/stringify.js
index de02670..b97710a 100644
--- a/lib/stringify.js
+++ b/lib/stringify.js
@@ -6,7 +6,7 @@ function escape(str) {
 	if(str === "*") {
 		return "*";
 	}
-	return str.replace(/(^[^A-Za-z_\\-]|[^A-Za-z_0-9\\-])/g, "\\$1");
+	return str.replace(/(^[^A-Za-z_\\-]|^\-\-|[^A-Za-z_0-9\\-])/g, "\\$1");
 }
 
 function stringifyWithoutBeforeAfter(tree) {
diff --git a/test/test-cases.js b/test/test-cases.js
index c3055bb..61a4fe4 100644
--- a/test/test-cases.js
+++ b/test/test-cases.js
@@ -55,10 +55,13 @@ module.exports = {
 		])
 	],
 
-	"class name starting with number": [
-		".\\5\\#-\\.5",
+	"class name starting with number or dash": [
+		".\\5\\#-\\.5 .\\--name.-name",
 		singleSelector([
-			{ type: "class", name: "5#-.5" }
+			{ type: "class", name: "5#-.5" },
+			{ type: "spacing", value: " " },
+			{ type: "class", name: "--name" },
+			{ type: "class", name: "-name" }
 		])
 	],
 
@@ -251,7 +254,7 @@ module.exports = {
 	],
 
 	"pseudo class with difficult content": [
-		":--anything-new(/* here is difficult ')][ .content */\nurl('Hello)World'), \"Hello)\\\".World\")",
+		":\\--anything-new(/* here is difficult ')][ .content */\nurl('Hello)World'), \"Hello)\\\".World\")",
 		singleSelector([
 			{ type: "pseudo-class", name: "--anything-new", content: "/* here is difficult ')][ .content */\nurl('Hello)World'), \"Hello)\\\".World\"" }
 		])
@@ -320,6 +323,28 @@ module.exports = {
 		])
 	],
 
+	"available nested pseudo classes": [
+		":not(:active):matches(:focus)",
+		singleSelector([
+			{ type: "nested-pseudo-class", name: "not", nodes: [
+				{
+					type: "selector",
+					nodes: [
+						{ type: "pseudo-class", name: "active" }
+					]
+				}
+			] },
+			{ type: "nested-pseudo-class", name: "matches", nodes: [
+				{
+					type: "selector",
+					nodes: [
+						{ type: "pseudo-class", name: "focus" }
+					]
+				}
+			] }
+		])
+	],
+
 	"nested pseudo class with nested selectors": [
 		":has(h1:not(:has(:visited)))",
 		singleSelector([