diff --git a/packages/astro/src/runtime/server/index.ts b/packages/astro/src/runtime/server/index.ts
index d3a31bf6b029..039ddc47fb64 100644
--- a/packages/astro/src/runtime/server/index.ts
+++ b/packages/astro/src/runtime/server/index.ts
@@ -542,6 +542,8 @@ export function createAstro(
 const toAttributeString = (value: any, shouldEscape = true) =>
 	shouldEscape ? String(value).replace(/&/g, '&').replace(/"/g, '"') : value;
 
+const kebab = (k: string) => k.toLowerCase() === k ? k : k.replace(/[A-Z]/g, match => `-${match.toLowerCase()}`);
+const toStyleString = (obj: Record<string, any>) => Object.entries(obj).map(([k, v]) => `${kebab(k)}:${v}`).join(';')
 const STATIC_DIRECTIVES = new Set(['set:html', 'set:text']);
 
 // A helper used to turn expressions into attribute key/value