/* ══════════════════════════════════════════
   layout.css — App structural layout
══════════════════════════════════════════ */

body {
  background: var(--bg-root);
  color: var(--text-primary);
  font-family: var(--font-body);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ─── Header ─── */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
}

.header-inner {
  max-width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  padding: 0 var(--space-6);
  gap: var(--space-8);
}

/* ─── Logo ─── */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.logo-icon {
  font-size: 1.4rem;
  color: var(--accent);
  line-height: 1;
  animation: rotateSlow 12s linear infinite;
}

.logo-text {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--text-primary);
  text-transform: uppercase;
}

/* ─── Nav ─── */
.main-nav {
  display: flex;
  gap: var(--space-2);
  flex: 1;
}

.nav-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-secondary);
  background: transparent;
  border: 1px solid transparent;
  transition: all var(--transition-fast);
}

.nav-btn:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
  border-color: var(--border-subtle);
}

.nav-btn.active {
  color: var(--accent);
  background: var(--accent-dim);
  border-color: var(--border-accent);
}

.nav-icon {
  font-style: normal;
}

/* ─── Session ─── */
.header-meta {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.session-time {
  color: var(--accent);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

/* ─── Main ─── */
.app-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* ─── Section ─── */
.section {
  display: none;
  flex: 1;
  height: calc(100vh - var(--header-height));
  overflow: hidden;
}

.section.active {
  display: flex;
}

/* ─── Control Panel (sidebar) ─── */
.control-panel {
  width: var(--panel-width);
  flex-shrink: 0;
  background: var(--bg-surface);
  border-right: 1px solid var(--border-subtle);
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-4) 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* Custom scrollbar */
.control-panel::-webkit-scrollbar {
  width: 4px;
}
.control-panel::-webkit-scrollbar-track {
  background: transparent;
}
.control-panel::-webkit-scrollbar-thumb {
  background: var(--border-subtle);
  border-radius: 2px;
}

/* ─── Panel blocks ─── */
.panel-block {
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--border-faint);
}

.panel-title {
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

/* ─── Visualizer area ─── */
.visualizer-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  padding: var(--space-5);
  gap: var(--space-4);
  background: var(--bg-root);
}