style: redesign hint buttons — rectangular pink with white icon, more spacing

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

assets/styles/app.css

@@ -46,6 +46,10 @@ body {
     vertical-align: middle;
 }
 
+#actors td:first-child {
+    padding-right: 12px;
+}
+
 .letter-input {
     width: 38px;
     height: 38px;
@@ -99,26 +103,24 @@ body {
 /* ── Popover ── */
 
 .popover-trigger {
-    width: 28px;
+    width: 38px;
     height: 28px;
-    border-radius: 50%;
-    border: 1.5px solid var(--border);
-    background: var(--surface);
+    border-radius: 6px;
+    border: none;
+    background: #F02287;
     cursor: pointer;
-    font-size: 12px;
+    font-size: 14px;
     font-weight: 600;
-    color: var(--text-muted);
+    color: #ffffff;
     display: flex;
     align-items: center;
     justify-content: center;
-    transition: border-color 0.15s, color 0.15s, background 0.15s;
+    transition: background 0.15s;
     box-shadow: 0 1px 3px var(--shadow-warm);
 }
 
 .popover-trigger:hover {
-    border-color: var(--orange);
-    color: var(--orange);
-    background: var(--surface-tint);
+    background: #d41a76;
 }
 
 .actor-popover {