diff --git a/index.js b/index.js
index 34e11fe..fc3fea6 100644
--- a/index.js
+++ b/index.js
@@ -1,12 +1,36 @@
-var docId = document.URL.match(/\/d\/([_A-Za-z0-9-]+)/)[1];
-var docHash = sha1(docId);
-var bgColor;
-switch (document.URL.match(/docs.google.com\/(\w+)/)[1]) {
-	case 'document': bgColor = [81, 142, 245, 255]; break;
-	case 'drawings': bgColor = [222, 83, 71, 255]; break;
-	case 'forms': bgColor = [114, 73, 188, 255]; break;
-	case 'presentation': bgColor = [245, 186, 19, 255]; break;
-	case 'spreadsheets': bgColor = [35, 165, 102, 255];
+class Config {
+  constructor(name, idRegex, bgColor, fgColor) {
+    this.name = name;
+    this.idRegex = idRegex;
+    this.bgColor = bgColor;
+    this.fgColor = fgColor;
+  }
+
+  matches(url) {
+    return url.match(this.idRegex);
+  }
+
+  docId(url) {
+    return this.matches(url)[1];
+  }
+}
+
+let configs = [
+  new Config("Google Docs", /docs.google.com\/document\/d\/([_A-Za-z0-9-]+)/, [81, 142, 245, 255], [255, 255, 255, 255]),
+  new Config("Google Drawings", /docs.google.com\/drawings\/d\/([_A-Za-z0-9-]+)/, [222, 83, 71, 255], [255, 255, 255, 255]),
+  new Config("Google Forms", /docs.google.com\/forms\/d\/([_A-Za-z0-9-]+)/, [114, 73, 188, 255], [255, 255, 255, 255]),
+  new Config("Google Slides", /docs.google.com\/presentation\/d\/([_A-Za-z0-9-]+)/, [245, 186, 19, 255], [255, 255, 255, 255]),
+  new Config("Google Sheets", /docs.google.com\/spreadsheets\/d\/([_A-Za-z0-9-]+)/, [35, 165, 102, 255], [255, 255, 255, 255]),
+];
+
+// Find a config that matches the current URL
+let config = configs.find(config => config.matches(document.URL));
+
+// If there is a config for the current URL, update the favicon based on that config
+if (config) {
+  let docId = config.docId(document.URL);
+  let docHash = sha1(docId);
+
+  let iconBase64 = new Identicon(docHash, { background: config.bgColor, foreground: config.fgColor }).toString();
+  document.querySelector('link[rel*="icon"]').href = 'data:image/png;base64,' + iconBase64;
 }
-var iconBase64 = new Identicon(docHash, { background: bgColor, foreground: [255, 255, 255, 255] }).toString();
-document.querySelector('link[rel*="icon"]').href = 'data:image/png;base64,' + iconBase64;