:root {
  --bg: #f5f5f5;
  --panel: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #d1d5db;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.app {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 1rem;
}

.panel {
  width: min(92vw, 400px);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
}

h1 {
  margin: 0 0 0.5rem;
  font-size: 1.25rem;
}

.back {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: normal;
  margin-right: 0.25rem;
}

.back:hover {
  color: var(--text);
}

.meta {
  display: flex;
  justify-content: space-between;
  margin: 0 0 0.75rem;
}

canvas {
  display: block;
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  touch-action: manipulation;
}

.hint {
  margin: 0.75rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}