:root {
  --bg: #ffffff;
  --panel: #f3f4f6;
  --border: #d1d5db;
  --text: #374151;
  --muted: #6b7280;
  --accent: #111827;

  --c-empty: #f9fafb;
  --c-wall: #374151;
  --c-start: #16a34a;
  --c-end: #dc2626;
  --c-visited: #bfdbfe;
  --c-frontier: #60a5fa;
  --c-path: #facc15;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Poppins", system-ui, sans-serif;
}

main {
  max-width: 860px;
  margin: 0 auto;
  padding: 24px 16px 32px;
}

h1 {
  margin: 0 0 4px;
  color: #1f2937;
  font-size: clamp(1.5rem, 4vw, 2.25rem);
}

.subtitle {
  margin-top: 0;
  color: var(--muted);
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  margin-bottom: 14px;
  box-shadow: 0 4px 12px rgba(17, 24, 39, 0.08);
}

.controls label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
}

button {
  background: var(--accent);
  color: white;
  border: 2px solid var(--accent);
  border-radius: 999px;
  padding: 7px 14px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease;
}

button:hover {
  background: white;
  color: var(--accent);
}

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

.status {
  margin-left: auto;
  font-size: 0.9rem;
  color: var(--muted);
}

canvas {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: white;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(17, 24, 39, 0.1);
}

.hint {
  color: var(--muted);
  font-size: 0.85rem;
}

select,
input[type="range"] {
  accent-color: #2563eb;
}

select {
  border: 1px solid var(--border);
  border-radius: 6px;
  background: white;
  color: var(--text);
  padding: 5px 8px;
}

@media (max-width: 640px) {
  .controls label,
  .controls button,
  .status {
    width: 100%;
  }

  .status {
    margin-left: 0;
  }
}