diff --git a/css.js b/css.js
index b50e0a5..4c15579 100644
--- a/css.js
+++ b/css.js
@@ -5,13 +5,13 @@ exports.CSSStyleDeclaration = CSSStyleDeclaration
 exports.CSSStyleSheet = CSSStyleSheet
 
 var path = require("path")
-, clearFn = (_, q, str) => q ? (q == "\"" && str.indexOf("'") == -1 ? "'" + str + "'" : _) :
+, clearFn = (_, q, str) => q ? (q = str.indexOf("'") == -1 ? "'" : "\"", q + str.replace(q === "'" ? /\\(")/g : /\\(')/g, "$1")) + q :
 	_.replace(/[\t\n]+/g, " ")
 	.replace(/ *([,;{}>~+\/]) */g, "$1")
 	.replace(/;(?=})/g, "")
 	.replace(/: +/g, ":")
 	.replace(/([ :,])0\.([0-9])/g, "$1.$2")
-, clear = s => s.replace(/(["'])((?:\\\1|.)*?)\1|[^"']+/g, clearFn).replace(/url\(("|')([^'"()\s]+)\1\)/g, "url($2)")
+, clear = s => s.replace(/("|')((?:\\\1|[^\1])*?)\1|[^"']+/g, clearFn).replace(/url\(("|')([^'"()\s]+)\1\)/g, "url($2)")
 , styleHandler = {
 	get(style, prop) {
 		if (prop === "cssText") {
@@ -110,7 +110,7 @@ var path = require("path")
 
 function CSSRule(text, parentStyleSheet, atType, parentRule = null) {
 	// Clear comments and trim
-	text = text.replace(/^\s+|\/\*[^*]*\*+([^/*][^*]*\*+)*\/|\s+$/g, "")
+	text = text.replace(/\/\*(?:[^*]|\*(?!\/))*\*\//g, "").trim()
 	var type = text[0] === "@" && text.slice(1, text.indexOf(" ")) || "style"
 	, rule = Object.create(ruleTypes[type] || ruleTypes[type === "page" || type === "font-face" || type === "counter-style" ? "style" : atType])
 	rule.cssText = text
@@ -149,29 +149,35 @@ CSSStyleSheet.prototype = {
 		this.rules.splice(idx > -1 ? idx : this.rules.length, 0, CSSRule(rule, this))
 	},
 	replaceSync(text) {
-		var m
-		, sheet = this
-		, re = /((?:("|')(?:\\.|(?!\2)[^\\])*?\2|[^"'}{;\/]|\/(?!\*))+)|(\/\*[\s\S]*?\*\/)|./g
-		, block = 0
-		, pos = 0
-		, arr = []
+		var qpos, sheet = this
 		sheet.rules = sheet.cssRules = []
 		sheet.warnings = []
-		for (; (m = re.exec(text)); ) {
-			if (m[0] === "{") {
-				block++
-			} else if (m[3] && block === 0) {
-				text = text.slice(0, m.index) + text.slice(re.lastIndex)
-				re.lastIndex = m.index
-			} else if (m[0] === ";" && block === 0 || m[0] === "}" && --block === 0) {
-				arr.push(pos, pos = re.lastIndex, m[0])
-			} else if (block < 0) {
-				throw "Invalid css"
+		for (var char, inQuote, depth = 0, start = 0, pos = 0, len = text.length; pos < len; pos++) {
+			char = text[pos]
+			if (char === "\\" && inQuote !== "/") {
+				pos++
+			} else if (inQuote) {
+				if (char === inQuote) {
+					if (char !== "/" || text[pos - 1] === "*") {
+						if (char === "/" && depth < 1) {
+							// Remove root level comments
+							text = text.slice(0, qpos) + text.slice(pos + 1)
+							pos = qpos - 1
+							len = text.length
+						}
+						inQuote = ""
+					}
+				}
+			} else if (char === "'" || char === "\"" || char === "/" && text[pos+1] === "*") {
+				inQuote = char
+				qpos = pos
+			} else if (char === "{") {
+				depth++
+			} else if (char === "}" && --depth < 1 || char === ";" && depth < 1) {
+				if (depth < 0) throw "Invalid css"
+				sheet.rules.push(CSSRule(text.slice(start, start = pos + 1), sheet, char))
 			}
 		}
-		for (m = 0; m < arr.length; m += 3) {
-			sheet.rules.push(CSSRule(text.slice(arr[m], arr[m + 1]), sheet, arr[m+2]))
-		}
 	},
 	toString(min) {
 		if (min) this.min = min
diff --git a/test/css.js b/test/css.js
index b1343b9..ef16cd5 100644
--- a/test/css.js
+++ b/test/css.js
@@ -49,14 +49,18 @@ describe("css.js {0}", describe.env === "browser" ? [["mock", exports], ["native
 			assert.end()
 		})
 
-		test("parse {i}", [
+		test("parse '{0}'", [
 			[" ", ""],
 			[" html {} body{  } ", ""],
+			["a{a:1}b{b:2}c{c:3}", "a{a:1}\nb{b:2}\nc{c:3}"],
+			["/*A*/a/*B\\*/{b:c}/**/d/**/{e:f}", "a{b:c}\nd{e:f}"],
+			["a\\,b{c:d}", "a\\,b{c:d}"],
 			[" * {margin:0} body { font-size: 1.4em; } p { color: red; }", "*{margin:0}\nbody{font-size:1.4em}\np{color:red}"],
 			["div {\n background: #00a400;\n background: linear-gradient(to bottom, rgb(214, 122, 127) 0%, hsla(237deg 74% 33% / 61%) 100%);}", "div{background:#00a400;background:linear-gradient(to bottom,rgb(214,122,127) 0%,hsla(237deg 74% 33%/61%) 100%)}"],
 			[" @import url('a.css') screen;  @import url(\"b.css\") screen; * { margin: 0; }", "@import 'a.css' screen;\n@import 'b.css' screen;\n*{margin:0}"],
 			["@media (min-width: 500px) {\n  body {\n    color: blue;\n  }\n}\n", "@media (min-width:500px){body{color:blue}}"],
 			["@media (min-width: 500px) {\n\n}\n", ""],
+			[".a { b: url('a\\'b') }", ".a{b:url(\"a'b\")}"],
 			//[":root{--my-test-variable:123px}.p{ width: var(--my-test-variable); }", ".p{width:123px}"],
 		], (text, expected, assert) => {
 			sheet.replaceSync(text)