Light theme: match APDU detail header bar to selected-row tint

Use the same blue-100 (#dbeafe) background on the detail header bar as
the selected row, for uniformity; dark theme unchanged.

frontend/index.html

@@ -115,6 +115,7 @@ body { font: 14px/1.5 system-ui, sans-serif; background: var(--bg); color: var(-
 .apdu-detail { display: flex; flex-direction: column; max-height: 40%; overflow-y: auto; border-top: 2px solid var(--accent); background: var(--bg-panel); flex-shrink: 0; }
 .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 strong { font-size: 13px; }
 .detail-body { padding: 8px 12px; font-family: monospace; font-size: 12px; line-height: 1.6; }
 .detail-body table { width: 100%; border-collapse: collapse; }