fix(index): use single-column grid to eliminate ghost cells

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: shettigarc

index.html

@@ -144,7 +144,7 @@
     /* Guide Grid */
     .guide-grid {
       display: grid;
-      grid-template-columns: repeat(auto-fill, minmax(480px, 1fr));
+      grid-template-columns: 1fr;
       gap: 1px;
       background: var(--border);
       border: 1px solid var(--border);

scripts/build-index.js

@@ -242,7 +242,7 @@ function generateIndexHtml(guides) {
     /* Guide Grid */
     .guide-grid {
       display: grid;
-      grid-template-columns: repeat(auto-fill, minmax(480px, 1fr));
+      grid-template-columns: 1fr;
       gap: 1px;
       background: var(--border);
       border: 1px solid var(--border);