Standardize header styles for test panel

The test panel drawer headers display inconsistent typography and toggle
indicators between the case creation form and test execution status.
This change aligns font properties and stateful indicator styles across
both sections to establish visual continuity in the interview view.

Author: kumi222

web/interview.html

@@ -284,8 +284,8 @@ <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

@@ -1425,16 +1425,43 @@ p {
   flex-basis: auto;
 }
 
+.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;
+  width: 0;
+  height: 0;
+  border-top: 4px solid transparent;
+  border-bottom: 4px solid transparent;
+  border-left: 6px solid var(--sub);
+  transition: transform 120ms ease;
+}
+
+.test-drawer details[open] summary::before,
+#results-toggle.open #results-chevron::before {
+  transform: rotate(90deg);
 }
 
 .results-body {