:root {
  --bg: #f5f5f0;
  --ink: #111111;
  --muted: #666666;
  --card: #ffffff;
  --line: #d8d8cf;
  --accent: #111111;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}

.hero {
  padding: 36px 20px 18px;
  max-width: 980px;
  margin: 0 auto;
}

h1, h2, p { margin-top: 0; }

h1 {
  font-size: clamp(42px, 9vw, 92px);
  letter-spacing: -0.08em;
  line-height: 0.9;
  margin-bottom: 12px;
}

h2 {
  font-size: 22px;
  letter-spacing: -0.03em;
  margin-bottom: 0;
}

.lead {
  font-size: 18px;
  color: var(--muted);
  max-width: 720px;
}

.eyebrow {
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--muted);
  margin-bottom: 6px;
  font-weight: 700;
}

main {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 20px 36px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 20px;
  margin: 18px 0;
  box-shadow: 0 8px 24px rgba(0,0,0,0.04);
}

.lock-card {
  border-color: #111111;
  box-shadow: 0 10px 30px rgba(0,0,0,0.08);
}

.section-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 16px;
}

label {
  display: block;
  font-size: 13px;
  font-weight: 700;
  margin: 12px 0 8px;
}

textarea,
input[type="password"] {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 14px;
  font: 16px/1.45 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  resize: vertical;
  color: var(--ink);
  background: #fbfbf7;
}

input[type="password"] {
  resize: none;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

button {
  appearance: none;
  border: none;
  background: var(--ink);
  color: #ffffff;
  padding: 12px 18px;
  border-radius: 999px;
  font-weight: 800;
  cursor: pointer;
}

button.secondary {
  background: #333333;
}

button.ghost {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--line);
}

button:active { transform: translateY(1px); }
button:disabled { opacity: 0.45; cursor: not-allowed; }

.note {
  color: var(--muted);
  font-size: 13px;
  margin: 12px 0 0;
}

.strong-note {
  color: #333333;
}

.stat {
  color: var(--muted);
  font-size: 12px;
  margin: 0;
  white-space: nowrap;
}

.canvas-wrap {
  overflow: auto;
  background: #eeeeea;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 12px;
}

canvas {
  display: block;
  background: white;
  max-width: none;
}

.file-box {
  border: 1px dashed #999999;
  border-radius: 16px;
  padding: 20px;
  text-align: center;
  cursor: pointer;
  background: #fbfbf7;
  margin-bottom: 16px;
}

.file-box input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.legend {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(74px, 1fr));
  gap: 12px;
}

.legend-item {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 8px 8px 10px;
  background: #fbfbf7;
  text-align: center;
}

.legend-item canvas {
  margin: 0 auto 6px;
  border-radius: 4px;
}

.legend-char {
  font: 700 13px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

footer {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 20px 36px;
  color: var(--muted);
  font-size: 12px;
}

@media (max-width: 640px) {
  .card { padding: 16px; border-radius: 18px; }
  .section-head { flex-direction: column; }
  button { width: 100%; }
  .controls { flex-direction: column; }
}