/**
 * Example side panel — reusable explanatory panel for example pages.
 *
 * Usage:
 *   1. Add <link rel="stylesheet" href="../assets/style/panel.css" />
 *   2. Wrap page body in <div class="ex-page-layout">
 *   3. Add <aside class="ex-panel" id="myPanel"> with content inside
 *   4. Add <button class="btn-panel-toggle"> in the header for mobile toggle
 *
 * On desktop (>900px): panel is always visible as a 300px left sidebar.
 * On tablet/mobile (≤900px): panel is hidden, toggled by .btn-panel-toggle.
 */

.ex-page-layout {
  display: flex;
  height: calc(100dvh - var(--ex-header-height, 50px));
  overflow: hidden;
}

.ex-panel {
  width: 300px;
  max-width: 100dvw;
  flex-shrink: 0;
  overflow-y: auto;
  border-right: 1px solid var(--ex-border);
  background: var(--ex-surface);
  padding: var(--ex-space-md) var(--ex-space-sm);
  display: flex;
  flex-direction: column;
  gap: var(--ex-space-sm);
}

.ex-panel::-webkit-scrollbar { width: 4px; }
.ex-panel::-webkit-scrollbar-thumb {
  background: var(--ex-border);
  border-radius: var(--ex-radius-full);
}

.ex-panel-heading {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--ex-primary);
  margin: 0 0 2px var(--ex-space-xs);
}

.ex-panel-intro {
  font-size: 12px;
  line-height: 1.5;
  color: var(--ex-text);
  opacity: 0.75;
  margin: 0;
  padding: 0 var(--ex-space-xs);
}

.ex-panel-subtitle {
  font-size: 11px;
  font-weight: 700;
  color: var(--ex-text);
  opacity: 0.6;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.ex-panel-divider {
  height: 1px;
  background: var(--ex-border);
  margin: 2px var(--ex-space-xs);
}

.ex-panel-hint {
  font-size: 11px;
  padding: 6px var(--ex-space-sm);
  background: var(--ex-hover);
  border-radius: var(--ex-radius-sm);
  border-left: 3px solid var(--ex-primary);
  line-height: 1.5;
  color: var(--ex-text);
}

.ex-panel-item {
  padding: 6px var(--ex-space-sm);
  border: 1px solid var(--ex-border);
  border-radius: var(--ex-radius-sm);
  background: var(--ex-bg);
  font-size: 11px;
  line-height: 1.5;
}

.ex-panel-item-label {
  font-weight: 600;
  color: var(--ex-primary);
  font-size: 12px;
}

.ex-panel-item-values {
  color: var(--ex-text);
  opacity: 0.7;
  font-size: 11px;
}

.ex-panel-item-default {
  display: inline-block;
  margin-left: 3px;
  font-size: 9px;
  background: var(--ex-primary);
  color: #fff;
  border-radius: 3px;
  padding: 0 3px;
  vertical-align: middle;
  opacity: 0.85;
}

.ex-panel-item-desc {
  color: var(--ex-text);
  opacity: 0.6;
  margin-top: 2px;
  font-size: 11px;
}

.ex-panel-code {
  font-family: monospace;
  font-size: 11px;
  line-height: 1.6;
  padding: var(--ex-space-sm);
  background: var(--ex-hover);
  border-left: 3px solid var(--ex-border);
  border-radius: var(--ex-radius-sm);
}

/* ── Header toggle button (visible only on mobile/tablet) ──────────────────── */

.btn-panel-toggle {
  display: none;
  align-items: center;
  gap: 5px;
  padding: 0 var(--ex-space-md);
  height: 34px;
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--ex-radius-sm);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: background var(--ex-transition);
}

.btn-panel-toggle:hover { background: rgba(255, 255, 255, 0.25); }

@media (max-width: 900px), (max-height: 500px) {
  .btn-panel-toggle { display: flex; }

  .ex-panel {
    position: fixed;
    left: 0;
    top: var(--ex-header-height, 50px);
    bottom: 0;
    width: min(320px, 90vw);
    z-index: 200;
    border-right: 1px solid var(--ex-border);
    border-bottom: none;
    max-height: none;
    overflow-y: auto;
    padding: var(--ex-space-md) var(--ex-space-sm);
    gap: var(--ex-space-sm);
    transform: translateX(-100%);
    transition: transform 280ms ease, box-shadow 280ms ease;
  }

  .ex-panel.open {
    transform: translateX(0);
    box-shadow: 4px 0 20px rgba(0, 0, 0, 0.15);
  }
}

/* ── Config panel sections ─────────────────────────────────────────────────── */

.config-section {
  flex-shrink: 0;
  margin-bottom: 12px;
  border: 1px solid var(--ex-border);
  border-radius: 6px;
  overflow: hidden;
}

.config-section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 10px;
  background: var(--ex-surface-alt);
  cursor: pointer;
  user-select: none;
  font-weight: 600;
  color: var(--ex-text);
}

.config-section-header:hover {
  background: var(--ex-hover);
}

.config-section-body {
  padding: 8px 10px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.config-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 2px 0;
}

.config-row label:not(.toggle) {
  color: var(--ex-text);
  cursor: pointer;
  flex: 1;
}

.config-subsection {
  margin-left: 12px;
  border-left: 2px solid var(--ex-border);
  padding-left: 8px;
  margin-top: 2px;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.config-subsection-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--ex-text);
  opacity: 0.5;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin: 4px 0 2px;
}