Reduced width of external link cards

This fixes the issue where on typical mobile phones, only one landing card shows up per row which does not look good.

Author: jiwonac

src/_css/landing.css

@@ -108,8 +108,8 @@
     flex-direction: column;
     align-items: center;
     gap: 0.5rem;
-    padding: 1rem 1.5rem;
-    width: 140px;
+    padding: 1rem;
+    width: 93px;
     background: var(--color-off-white);
     filter: drop-shadow(1px 2px 3px rgba(0, 0, 0, 0.1));
     text-decoration: none;