:root {
  color-scheme: light dark;
  --bg: #0f1115;
  --card: #171a21;
  --border: #2a2e37;
  --text: #e6e8ec;
  --muted: #9aa1ac;
  --accent: #6ea8fe;

  --c-empty: #171a21;
  --c-wall: #2a2e37;
  --c-start: #4ade80;
  --c-end: #f87171;
  --c-visited: #3b4a6b;
  --c-frontier: #6ea8fe;
  --c-path: #facc15;
  --c-grid-line: #23262e;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, "Segoe UI", "Hiragino Kaku Gothic ProN", sans-serif;
  padding: 24px;
  display: flex;
  justify-content: center;
}

.wrap {
  width: 100%;
  max-width: 1100px;
}

header h1 {
  font-size: 1.5rem;
  margin: 0 0 4px;
}

header .sub {
  color: var(--muted);
  margin: 0 0 20px;
  font-size: 0.9rem;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 16px;
  margin-bottom: 14px;
}

.toolbar label {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 0.75rem;
  color: var(--muted);
}

.toolbar select,
.toolbar input[type="range"] {
  accent-color: var(--accent);
}

.toolbar select {
  background: #0f1115;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 8px;
}

button {
  background: var(--accent);
  color: #0f1115;
  border: none;
  border-radius: 8px;
  padding: 9px 14px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
}

button:hover {
  opacity: 0.9;
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

#maze-btn,
#clear-walls-btn,
#clear-all-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}

.status {
  margin-left: auto;
  font-size: 0.85rem;
  color: var(--muted);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 10px;
}

.legend span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.sw {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  display: inline-block;
}

.sw.start { background: var(--c-start); }
.sw.end { background: var(--c-end); }
.sw.wall { background: var(--c-wall); border: 1px solid var(--border); }
.sw.visited { background: var(--c-visited); }
.sw.frontier { background: var(--c-frontier); }
.sw.path { background: var(--c-path); }

canvas {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--c-empty);
  cursor: crosshair;
  touch-action: none;
}

.hint {
  color: var(--muted);
  font-size: 0.8rem;
  margin-top: 10px;
}