/* ── Design tokens ─────────────────────────────────────────────────────────── */

:root {
  color-scheme: light dark;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  /* Tile colors — light mode */
  --c-wall:          #2d3748;
  --c-empty:         #edf2f7;
  --c-player:        #3182ce;
  --c-player-carry:  #2b6cb0;
  --c-block:         #dd6b20;
  --c-goal:          #38a169;
  --c-border:        #a0aec0;

  /* UI colors — light mode */
  --c-bg:            #f6f7f9;
  --c-surface:       #ffffff;
  --c-text:          #1f2933;
  --c-text-subtle:   #4a5568;
  --c-accent:        #3182ce;
  --c-btn:           #e2e8f0;
  --c-btn-hover:     #cbd5e0;
  --c-btn-active:    #a0aec0;
  --c-overlay:       rgba(0, 0, 0, 0.45);
}

@media (prefers-color-scheme: dark) {
  :root {
    --c-wall:          #1a202c;
    --c-empty:         #2d3748;
    --c-player:        #63b3ed;
    --c-player-carry:  #4299e1;
    --c-block:         #f6ad55;
    --c-goal:          #68d391;
    --c-border:        #4a5568;

    --c-bg:            #1a202c;
    --c-surface:       #2d3748;
    --c-text:          #f7fafc;
    --c-text-subtle:   #a0aec0;
    --c-accent:        #63b3ed;
    --c-btn:           #4a5568;
    --c-btn-hover:     #718096;
    --c-btn-active:    #2d3748;
    --c-overlay:       rgba(0, 0, 0, 0.65);
  }
}

/* ── Reset ─────────────────────────────────────────────────────────────────── */

*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100dvh;
  background: var(--c-bg);
  color: var(--c-text);
  display: grid;
  place-items: start center;
}

/* ── App shell ─────────────────────────────────────────────────────────────── */

#app {
  width: min(32rem, 100%);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.app-header h1 {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* ── Status region ─────────────────────────────────────────────────────────── */

.status-region {
  margin: 0;
  min-height: 1.4em;
  font-size: 0.875rem;
  color: var(--c-text-subtle);
}

/* ── HUD ───────────────────────────────────────────────────────────────────── */

.hud {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.hud-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--c-text-subtle);
  margin-right: 0.25rem;
}

.hud-level {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex: 1;
  min-width: 0;
}

#level-select {
  flex: 1;
  min-width: 0;
  background: var(--c-surface);
  color: var(--c-text);
  border: 1px solid var(--c-border);
  border-radius: 4px;
  padding: 0.25rem 0.5rem;
  font: inherit;
  font-size: 0.875rem;
}

#level-select:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 1px;
}

.hud-moves {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  white-space: nowrap;
}

#moves-count {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  min-width: 2ch;
}

.hud-carry {
  font-size: 0.8rem;
  color: var(--c-block);
  font-weight: 600;
  white-space: nowrap;
}

/* ── Board ─────────────────────────────────────────────────────────────────── */

.board {
  display: grid;
  /* grid-template-columns set dynamically by renderer.js */
  gap: 1px;
  background: var(--c-border);
  border: 2px solid var(--c-border);
  border-radius: 4px;
  overflow: hidden;
  width: 100%;
  aspect-ratio: auto; /* rows are determined by cell count */
}

/* Suppress the default focus ring on the board element itself.
   Keyboard focus is still active (tabindex="-1"); the game responds to keys
   as soon as the board holds focus. We use :focus-visible to keep the ring
   when navigating by Tab for accessibility. */
.board:focus:not(:focus-visible) {
  outline: none;
}

/* ── Cells ─────────────────────────────────────────────────────────────────── */

.cell {
  aspect-ratio: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 0;
}

.cell-wall  { background: var(--c-wall); }
.cell-empty { background: var(--c-empty); }

.cell-goal {
  background: var(--c-empty);
  position: relative;
}
/* Goal marker — a small indicator in the center */
.cell-goal::after {
  content: '';
  width: 40%;
  height: 40%;
  border-radius: 50%;
  background: var(--c-goal);
  opacity: 0.8;
}

.cell-player {
  background: var(--c-player);
  border-radius: 30%;
  position: relative;
}

/* Directional arrow — points in the facing direction.
   Uses a CSS border-trick triangle so it scales with cell size. */
.cell-player::after {
  content: '';
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 0;
  height: 0;
  border-top: 25% solid transparent;
  border-bottom: 25% solid transparent;
}

.cell-player[data-facing="right"]::after {
  right: 8%;
  border-left: 28% solid rgba(255, 255, 255, 0.75);
}

.cell-player[data-facing="left"]::after {
  left: 8%;
  border-right: 28% solid rgba(255, 255, 255, 0.75);
}

/* Carrying state: brighter outline + a small block pip on the facing side */
.cell-player-carrying {
  background: var(--c-player-carry);
  outline: 2px solid var(--c-block);
  outline-offset: -2px;
}

.cell-player-carrying::before {
  content: '';
  position: absolute;
  bottom: 10%;
  width: 28%;
  height: 28%;
  background: var(--c-block);
  border-radius: 3px;
}

.cell-player-carrying[data-carry-side="right"]::before {
  right: 6%;
}

.cell-player-carrying[data-carry-side="left"]::before {
  left: 6%;
}

.cell-block {
  background: var(--c-block);
  border-radius: 4px;
}

/* ── Controls ──────────────────────────────────────────────────────────────── */

.controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.375rem;
}

.controls-row {
  display: flex;
  gap: 0.375rem;
  justify-content: center;
}

.controls-meta {
  margin-top: 0.25rem;
}

.btn-control {
  appearance: none;
  background: var(--c-btn);
  color: var(--c-text);
  border: none;
  border-radius: 6px;
  padding: 0.5rem 0.75rem;
  font: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  min-width: 4.5rem;
  transition: background 0.1s;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
}

.btn-control:hover {
  background: var(--c-btn-hover);
}

.btn-control:active {
  background: var(--c-btn-active);
  transform: scale(0.97);
}

.btn-control:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 2px;
}

.btn-interact {
  background: var(--c-block);
  color: #fff;
}

.btn-interact:hover  { filter: brightness(1.1); }
.btn-interact:active { filter: brightness(0.9); }

.btn-meta {
  font-size: 0.8rem;
  padding: 0.4rem 0.6rem;
  min-width: 4rem;
  opacity: 0.85;
}

/* ── Trace recorder ───────────────────────────────────────────────────────── */

.trace-panel {
  border: 1px solid var(--c-border);
  border-radius: 6px;
  background: var(--c-surface);
  padding: 0.625rem;
}

.trace-panel-complete {
  position: fixed;
  z-index: 110;
  right: 1rem;
  bottom: 1rem;
  width: min(34rem, calc(100% - 2rem));
  box-shadow: 0 8px 32px rgba(0,0,0,0.25);
}

.trace-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
}

.trace-status {
  margin: 0.4rem 0 0;
  min-height: 1.2em;
  color: var(--c-text-subtle);
  font-size: 0.8rem;
}

.trace-output {
  display: block;
  width: 100%;
  min-height: 8rem;
  max-height: 35dvh;
  margin-top: 0.5rem;
  resize: vertical;
  border: 1px solid var(--c-border);
  border-radius: 4px;
  padding: 0.5rem;
  background: var(--c-bg);
  color: var(--c-text);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.75rem;
  line-height: 1.35;
}

.trace-output[hidden] {
  display: none;
}

/* ── Completion dialog ─────────────────────────────────────────────────────── */

.completion-dialog {
  position: fixed;
  inset: 0;
  background: var(--c-overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.completion-dialog[hidden] {
  display: none;
}

.dialog-content {
  background: var(--c-surface);
  color: var(--c-text);
  border-radius: 12px;
  padding: 2rem;
  text-align: center;
  width: min(20rem, calc(100% - 2rem));
  box-shadow: 0 8px 32px rgba(0,0,0,0.25);
}

.dialog-content h2 {
  margin: 0 0 0.5rem;
  font-size: 1.5rem;
}

.dialog-content p {
  margin: 0 0 1.25rem;
  color: var(--c-text-subtle);
  font-size: 0.9rem;
}

.dialog-actions {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
}

.btn-dialog {
  appearance: none;
  background: var(--c-accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 0.6rem 1.25rem;
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: filter 0.1s;
  touch-action: manipulation;
}

.btn-dialog:hover  { filter: brightness(1.1); }
.btn-dialog:active { filter: brightness(0.9); }
.btn-dialog:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: 3px;
}

.btn-secondary {
  background: var(--c-btn);
  color: var(--c-text);
}

/* ── Mobile / narrow viewport ──────────────────────────────────────────────── */

@media (max-width: 480px) {
  #app {
    padding: 0.75rem;
    gap: 0.5rem;
  }

  .btn-control {
    font-size: 0.8rem;
    padding: 0.45rem 0.6rem;
    min-width: 3.75rem;
  }

  .app-header h1 {
    font-size: 1.25rem;
  }
}