Fix empty custom property parsing

lib/parser.js

@@ -139,10 +139,12 @@ class Parser {
     if (brackets.length > 0) this.unclosedBracket(bracket)
 
     if (end && colon) {
-      while (tokens.length) {
-        token = tokens[tokens.length - 1][0]
-        if (token !== 'space' && token !== 'comment') break
-        this.tokenizer.back(tokens.pop())
+      if (!customProperty) {
+        while (tokens.length) {
+          token = tokens[tokens.length - 1][0]
+          if (token !== 'space' && token !== 'comment') break
+          this.tokenizer.back(tokens.pop())
+        }
       }
       this.decl(tokens, customProperty)
     } else {
@@ -208,7 +210,15 @@ class Parser {
       node.raws.before += node.prop[0]
       node.prop = node.prop.slice(1)
     }
-    let firstSpaces = this.spacesAndCommentsFromStart(tokens)
+
+    let firstSpaces = []
+    let next
+    while (tokens.length) {
+      next = tokens[0][0]
+      if (next !== 'space' && next !== 'comment') break
+      firstSpaces.push(tokens.shift())
+    }
+
     this.precheckMissedSemicolon(tokens)
 
     for (let i = tokens.length - 1; i >= 0; i--) {
@@ -242,12 +252,12 @@ class Parser {
     }
 
     let hasWord = tokens.some(i => i[0] !== 'space' && i[0] !== 'comment')
-    this.raw(node, 'value', tokens)
+
     if (hasWord) {
-      node.raws.between += firstSpaces
-    } else {
-      node.value = firstSpaces + node.value
+      node.raws.between += firstSpaces.map(i => i[1]).join('')
+      firstSpaces = []
     }
+    this.raw(node, 'value', firstSpaces.concat(tokens), customProperty)
 
     if (node.value.includes(':') && !customProperty) {
       this.checkMissedSemicolon(tokens)
@@ -395,7 +405,7 @@ class Parser {
     if (node.type !== 'comment') this.semicolon = false
   }
 
-  raw(node, prop, tokens) {
+  raw(node, prop, tokens, customProperty) {
     let token, type
     let length = tokens.length
     let value = ''
@@ -405,7 +415,7 @@ class Parser {
     for (let i = 0; i < length; i += 1) {
       token = tokens[i]
       type = token[0]
-      if (type === 'space' && i === length - 1) {
+      if (type === 'space' && i === length - 1 && !customProperty) {
         clean = false
       } else if (type === 'comment') {
         prev = tokens[i - 1]