Update .button class to have orange background

- Update _sass/_layout.scss
  - Change .button background from $site-blue to #ff7a00 (orange)
  - Update hover state to #cc6200 (darker orange)
  - Maintains white text color for accessibility

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: theodorosploumis

_sass/_layout.scss

@@ -195,14 +195,14 @@
   display: inline-block;
   text-decoration: none;
   padding: 4px 8px;
-  background: $site-blue;
+  background: #ff7a00;
   color: #fff !important;
   border-radius: 3px;
 
   &:hover,
   &:focus {
-    background: #fff;
-    color: $site-blue !important;
+    background: #cc6200;
+    color: #fff !important;
     text-decoration: none;
   }
 }