APDU list + detail: hover and the detail header follow the theme tints

- the detail header used --bg-input in dark mode (plus a light-only #dbeafe
  override), so it only matched the list selection in the light theme; it now
  uses var(--selected-bg) — the same variable as the selected row — so the two
  are in sync in both themes (light unchanged)
- .apdu-entry:hover used --bg-panel (a grey in the same family as the GET
  RESPONSE pair rows); both themes now set --hover-bg — the accent at 16%
  (dark) / 10% (light), a translucent tint that stacks with whatever the row's
  background is — and a single hover rule uses it: hovering tints the row
  blue, lighter than the selection and a different hue from the pair rows.
  The rules stay ordered .apdu-pair → :hover → .selected, so hovering the
  selected row keeps its selection colour
- Node tests pin the hover variable per theme, the hover rule (and that the
  old grey rule is gone) and the detail header's variable; 540 Python +
  80 Node tests
- SW cache simtrace-analyser-v91 (cosmetic, no version bump)

frontend/index.html

@@ -20,6 +20,7 @@
     --bg-input: #334155;
     --selected-bg: #1e3a8a;   /* a blue tint, so a selected row stands out
                                  from the GET RESPONSE pair rows */
+    --hover-bg: rgba(59, 130, 246, 0.16);   /* a slight blue on hover */
     --border: #475569;
     --text: #e2e8f0;
     --text-muted: #94a3b8;
@@ -54,6 +55,7 @@
     --bg-panel: #e5e7eb;
     --bg-input: #ffffff;
     --selected-bg: #dbeafe;
+    --hover-bg: rgba(59, 130, 246, 0.10);
     --border: #d1d5db;
     --text: #1f2937;
     --text-muted: #6b7280;
@@ -149,7 +151,7 @@ body { font: 14px/1.5 system-ui, sans-serif; background: var(--bg); color: var(-
 .apdu-list { flex: 1 1 0; min-height: 0; overflow-y: auto; padding: 8px; }
 .apdu-entry { display: flex; gap: 12px; padding: 3px 12px; border-bottom: 1px solid var(--bg-panel); cursor: pointer; align-items: baseline; }
 .apdu-entry.apdu-pair { background: var(--pair-row); }
-.apdu-entry:hover { background: var(--bg-panel); }
+.apdu-entry:hover { background: var(--hover-bg); }
 .apdu-entry.selected { background: var(--selected-bg); }
 .apdu-time { color: var(--text-muted); font-family: monospace; white-space: nowrap; min-width: 80px; }
 .apdu-type { color: var(--text); font-weight: 600; min-width: 150px; }
@@ -182,8 +184,7 @@ body { font: 14px/1.5 system-ui, sans-serif; background: var(--bg); color: var(-
 .splitter:hover::after, .splitter.active::after { background: radial-gradient(circle, var(--text) 1px, transparent 1px); background-size: 6px 6px; }
 .splitter:hover, .splitter.active { background: var(--accent); }
 .apdu-detail .detail-empty { padding: 24px; color: var(--text-muted); text-align: center; }
-.detail-header { display: flex; align-items: center; justify-content: space-between; padding: 8px 12px; background: var(--bg-input); border-bottom: 1px solid var(--border); }
-[data-theme="light"] .detail-header { background: #dbeafe; }
+.detail-header { display: flex; align-items: center; justify-content: space-between; padding: 8px 12px; background: var(--selected-bg); border-bottom: 1px solid var(--border); }
 .detail-header strong { font-size: 13px; }
 .decrypt-strip { padding: 6px 12px; border-top: 1px solid var(--border); background: var(--bg-panel); font-size: 12px; display: flex; gap: 6px; align-items: center; flex-wrap: wrap; }
 .decrypt-strip input { background: var(--bg-input); color: var(--text); border: 1px solid var(--border); border-radius: 4px; padding: 3px 8px; font-family: monospace; width: 260px; }

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simtrace-analyser-v90';
+const CACHE = 'simtrace-analyser-v91';
 
 const PRECACHE = [
     'index.html',

frontend/tests/style.test.js

@@ -37,6 +37,19 @@ test('the APDU selection is a blue tint in both themes', () => {
 	assert.doesNotMatch(src, /--selected-bg: var\(--bg-input\)/);
 });
 
+test('the APDU hover is a slight blue tint in both themes', () => {
+	assert.match(src, /\.apdu-entry:hover \{ background: var\(--hover-bg\); \}/);
+	assert.match(src, /--hover-bg: rgba\(59, 130, 246, 0\.16\);/);   // dark
+	assert.match(src, /--hover-bg: rgba\(59, 130, 246, 0\.10\);/);   // light
+	// The hover must not fall back to the pair rows' grey or the selection.
+	assert.doesNotMatch(src, /\.apdu-entry:hover \{ background: var\(--bg-panel\); \}/);
+});
+
+test('the detail header follows the list selection in both themes', () => {
+	assert.match(src, /\.detail-header \{[^}]*background: var\(--selected-bg\);/);
+	assert.doesNotMatch(src, /\[data-theme="light"\] \.detail-header/);
+});
+
 // ── trace topbar layout ────────────────────────────────────────────────
 
 test('the view selector sits over the side panel at the panel width', () => {