Standardize header styles for test panel

Align section header font properties and toggle indicators across

both the Add a case and Test results drawers for consistency.

Author: kumi222

web/interview.html

@@ -275,8 +275,8 @@ <h1 id="problem-title">Loading interview...</h1>
             <ol id="candidate-case-list" class="small"></ol>
           </details>
           <button id="results-toggle" type="button">
+            <span id="results-chevron" aria-hidden="true"></span>
             <span id="results-label">Test results</span>
-            <span id="results-chevron">v</span>
           </button>
           <div id="results-body" class="results-body">
             <p class="muted small">

web/styles.css

@@ -1413,16 +1413,40 @@ p {
   background: var(--surface);
 }
 
+.test-drawer summary::-webkit-details-marker,
+.test-drawer summary::marker {
+  display: none;
+}
+
+.test-drawer summary,
 #results-toggle {
   display: flex;
+  align-items: center;
+  gap: 0.5rem;
   width: 100%;
-  justify-content: space-between;
+  padding: 0.5rem 1rem;
   border: 0;
   background: transparent;
   color: var(--sub);
-  padding: 0.5rem 1rem;
-  cursor: pointer;
+  font-family: inherit;
+  font-size: 0.875rem;
   font-weight: 700;
+  cursor: pointer;
+  text-align: left;
+}
+
+.test-drawer summary::before,
+#results-chevron::before {
+  content: "▶";
+  display: inline-block;
+  font-size: 0.75rem;
+  color: var(--sub);
+  transition: transform 120ms ease;
+}
+
+.test-drawer details[open] summary::before,
+#results-toggle.open #results-chevron::before {
+  transform: rotate(90deg);
 }
 
 .results-body {