properly escape backslashes in quotes in variables

src/utils.rs

@@ -126,7 +126,10 @@ pub(crate) fn read_until_closing_quote<I: Iterator<Item = Token>>(
                 is_escaped = false;
                 continue;
             }
-            TokenKind::Symbol(Symbol::BackSlash) if !is_escaped => is_escaped = true,
+            TokenKind::Symbol(Symbol::BackSlash) if !is_escaped => {
+                t.push(tok);
+                is_escaped = true
+            },
             TokenKind::Symbol(Symbol::BackSlash) => {
                 is_escaped = false;
                 t.push(tok);

tests/variables.rs

@@ -98,3 +98,8 @@ test!(
     "a {\n  $a: red\n}\n\nb {\n  color: blue;\n}\n",
     "b {\n  color: blue;\n}\n"
 );
+test!(
+    properly_escapes_backslash,
+    "a {\n  $a: unquote(\"\\\\0 \");\n  color: $a;\n}\n",
+    "a {\n  color: \\0 ;\n}\n"
+);