fix: divider line — shorter, thicker, dark; error map full size, more spacing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kaixubuilds

assets/css/style.css

@@ -227,8 +227,13 @@ nav {
   gap: 10px; margin-bottom: 28px;
 }
 @media (max-width: 700px) { .img-strip { grid-template-columns: repeat(2, 1fr); } }
-.img-strip .img-cell:last-child {
-  border-left: 1px solid var(--rule); padding-left: 10px;
+.img-cell--separated {
+  position: relative; margin-left: 18px;
+}
+.img-cell--separated::before {
+  content: '';
+  position: absolute; left: -14px; top: 50%; transform: translateY(-50%);
+  width: 2px; height: 52%; background: var(--ink-2); border-radius: 2px;
 }
 
 .img-cell { }

index.html

@@ -125,7 +125,7 @@ <h2 class="sec-title">One correct answer per problem.<br>Evaluated at the pixel.
         <img src="assets/img/eval_normalized_output.png" alt="Model output (Nano Banana 2)" />
         <div class="cap">Model output <span style="color:var(--muted)">(Nano Banana 2)</span></div>
       </div>
-      <div class="img-cell">
+      <div class="img-cell img-cell--separated">
         <img id="diff-img" src="assets/img/eval_diff_cie76_0.png" alt="Pixel error map" />
         <div class="cap">Error map <span style="color:var(--muted)">(drag slider)</span></div>
       </div>