fix: use toString on properties in replaceSymbols (#63)

Author: evilebottnawi

src/replaceSymbols.js

@@ -3,15 +3,18 @@ import replaceValueSymbols from "./replaceValueSymbols.js";
 const replaceSymbols = (css, replacements) => {
   css.walk(node => {
     if (node.type === "decl" && node.value) {
-      node.value = replaceValueSymbols(node.value, replacements);
+      node.value = replaceValueSymbols(node.value.toString(), replacements);
     } else if (node.type === "rule" && node.selector) {
-      node.selector = replaceValueSymbols(node.selector, replacements);
+      node.selector = replaceValueSymbols(
+        node.selector.toString(),
+        replacements
+      );
     } else if (
       node.type === "atrule" &&
       node.params &&
       ["media", "supports"].includes(node.name.toLowerCase())
     ) {
-      node.params = replaceValueSymbols(node.params, replacements);
+      node.params = replaceValueSymbols(node.params.toString(), replacements);
     }
   });
 };