Polish Query Engine card spacing: balance gap above/below ops box

- Add margin-top: 0.65rem (with transition) to plan-expand.lit so the
  gap between Optimize chip and the nested ops box matches the card's
  bottom padding (1.1rem), giving visual balance above and below
- Increase opt-connector height 5px → 8px for a more visible connection

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: githajae

_sass/custom/_research-interests.scss

@@ -186,17 +186,19 @@ body.page--research-interests #main {
   overflow: hidden;
   max-height: 0;
   opacity: 0;
-  transition: max-height 0.45s ease 0.1s, opacity 0.4s ease 0.15s;
+  margin-top: 0;
+  transition: max-height 0.45s ease 0.1s, opacity 0.4s ease 0.15s, margin-top 0.4s ease 0.1s;
 
   &.lit {
-    max-height: 70px;
+    max-height: 80px;
     opacity: 1;
+    margin-top: 0.65rem;
   }
 
   // Small vertical line from Optimize chip down to the ops box
   .opt-connector {
     width: 1px;
-    height: 5px;
+    height: 8px;
     background: rgba(0, 113, 227, 0.3);
     margin: 0 auto;
   }