/* ── LAYOUT ── */
/* Two-column viewport-fit layout: controls left | resizer | chart right */

/* ── APP SHELL ── */
.app-wrapper {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
  max-width: 1600px;
  margin: 0 auto;
}

/* ── ZONE 1: HEADER (full-width sticky) ── */
#app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  padding: 0 var(--space-8);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
  background-color: var(--bg-main);
  z-index: var(--z-header);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.header-title {
  font-size: var(--text-xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.header-title span {
  color: var(--accent-orange);
}

.header-badge {
  font-size: var(--text-xs);
  color: var(--text-muted);
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-pill);
  padding: 2px var(--space-2);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.header-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--text-muted);
  font-size: var(--text-sm);
  transition: color var(--transition-ui);
}

.header-link:hover {
  color: var(--text-primary);
}

/* ── BODY SPLIT: controls left | resizer | chart right ── */
/* grid-template-columns is set by resizer.js after first paint */
.body-split {
  display: grid;
  grid-template-columns: 460px 6px 1fr;
  flex: 1;
  min-height: 0;
}

/* ── DRAG RESIZER HANDLE ── */
#resizer {
  order: 2;
  width: 6px;
  cursor: col-resize;
  background: var(--border-subtle);
  transition: background var(--transition-ui);
  position: relative;
  flex-shrink: 0;
  z-index: var(--z-tooltip);
}

#resizer::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 2px;
  height: 32px;
  border-radius: var(--radius-pill);
  background: var(--text-muted);
  opacity: 0.4;
  transition: opacity var(--transition-ui), height var(--transition-ui);
}

#resizer:hover,
#resizer.dragging {
  background: var(--accent-orange);
}

#resizer:hover::after,
#resizer.dragging::after {
  opacity: 1;
  height: 48px;
  background: #fff;
}

/* ── LEFT PANEL: controls ── */
#controls {
  order: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  padding: var(--space-6) var(--space-6);
  overflow-y: auto;
  background: var(--bg-main);
  min-height: 0;
  min-width: 260px;
}

/* Thin custom scrollbar for controls panel */
#controls::-webkit-scrollbar       { width: 4px; }
#controls::-webkit-scrollbar-track { background: transparent; }
#controls::-webkit-scrollbar-thumb {
  background: var(--border-subtle);
  border-radius: var(--radius-pill);
}

/* ── CONTROL GROUP: label + content ── */
.controls-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.controls-group-label {
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* Preset buttons — 2×2 grid with generous gaps */
.preset-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3);
}

/* Playback — single row, Play stretches to fill */
.playback-row {
  display: flex;
  gap: var(--space-3);
  align-items: center;
}

.playback-row .btn-primary {
  flex: 1;
}

/* Horizontal separator between sections */
.controls-sep {
  height: 1px;
  background: var(--border-subtle);
  flex-shrink: 0;
}

/* ── STEP INFO ── */
#info {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.step-description {
  font-size: var(--text-sm);
  color: var(--text-primary);
  min-height: 20px;
  line-height: 1.7;
}

.step-counter {
  font-size: var(--text-xs);
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.step-counter strong {
  color: var(--accent-orange);
}

/* ── LEGEND — pinned to bottom via margin-top: auto ── */
#legend {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: auto;
  padding-top: var(--space-4);
  flex-shrink: 0;
}

.legend-label {
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.legend-chips {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3) var(--space-4);
}

.legend-chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-xs);
  color: var(--text-muted);
}

.legend-chip-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ── RIGHT PANEL: bar chart fills full height ── */
#canvas {
  order: 3;
  display: flex;
  flex-direction: column;
  padding: var(--space-6);
  min-height: 0;
  min-width: 300px;
  background: var(--bg-main);
}

#bar-chart {
  flex: 1;
  min-height: 0;
  height: auto;
}

/* ── DRAGGING STATE — applied to body ── */
body.is-resizing {
  cursor: col-resize;
  user-select: none;
}

body.is-resizing #controls,
body.is-resizing #canvas {
  pointer-events: none;
}

/* ── MOBILE LAYOUT (≤ 600px) ── */
@media (max-width: 600px) {

  /* App shell scrolls naturally on mobile — no fixed viewport height */
  .app-wrapper {
    height: auto;
    overflow: visible;
    min-height: 100vh;
  }

  /* Header shrinks padding and font */
  #app-header {
    padding: 0 var(--space-4);
    height: 52px;
  }

  .header-title {
    font-size: var(--text-lg);
  }

  .header-badge {
    display: none;
  }

  /* Stack panels vertically: controls on top, chart below */
  .body-split {
    display: flex;
    flex-direction: column;
    height: auto;
  }

  /* Hide the drag resizer entirely on mobile */
  #resizer {
    display: none;
  }

  /* Controls panel — full width, natural height, no overflow scroll */
  #controls {
    order: 1;
    min-width: unset;
    min-height: unset;
    overflow-y: visible;
    padding: var(--space-5) var(--space-4);
    border-right: none;
    border-bottom: 1px solid var(--border-subtle);
  }

  /* Legend unpins from bottom — flows naturally in the controls column */
  #legend {
    margin-top: var(--space-4);
  }

  /* Preset grid stays 2 cols — fits fine on mobile */
  .preset-grid {
    grid-template-columns: 1fr 1fr;
  }

  /* Playback row wraps if screen is very narrow */
  .playback-row {
    flex-wrap: wrap;
  }

  /* Canvas panel — full width, fixed height for the chart */
  #canvas {
    order: 2;
    min-width: unset;
    min-height: unset;
    padding: var(--space-4);
    height: 360px;
    flex-shrink: 0;
  }

  /* Bar chart fills the fixed canvas height */
  #bar-chart {
    height: 100%;
    min-height: unset;
  }

  /* Custom input fills full width on mobile */
  .custom-input {
    min-width: unset;
    width: 100%;
  }

  .custom-input-row {
    flex-wrap: wrap;
  }
}