:root {
  --bg: #0a0a0a;
  --surface: #141414;
  --surface-2: #1c1c1c;
  --border: #2a2a2a;
  --text: #f5f5f5;
  --text-dim: #9a9a9a;
  --accent: #f5f5f5;
  --accent-fg: #0a0a0a;
  --radius: 14px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
}

body {
  min-height: 100dvh;
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

a { color: inherit; text-decoration: none; }

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 24px 20px 40px;
}

.page-header {
  margin: 16px 0 24px;
}
.page-header h1 {
  font-size: 34px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0;
}
.subtitle {
  color: var(--text-dim);
  margin: 6px 0 0;
  font-size: 15px;
}

.back {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px; height: 40px;
  margin: 0 0 8px -8px;
  border-radius: 50%;
  font-size: 22px;
  color: var(--text-dim);
}
.back:active { background: var(--surface); }

/* Index cards */
.card-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}
.card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  transition: background 0.15s ease;
}
.card:active { background: var(--surface-2); }
.card-title {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.card-meta {
  margin-top: 4px;
  color: var(--text-dim);
  font-size: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

/* Overview */
.description {
  color: var(--text-dim);
  margin: 0 0 24px;
}
.step-list {
  list-style: none;
  counter-reset: step;
  margin: 0 0 32px;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.step-list li {
  background: var(--surface);
  padding: 14px 18px;
  display: grid;
  grid-template-columns: 28px 1fr auto;
  align-items: center;
  gap: 12px;
}
.step-num {
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
  font-size: 14px;
}
.step-name { font-weight: 500; }
.step-dur {
  color: var(--text-dim);
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 16px 20px;
  border-radius: var(--radius);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  user-select: none;
  transition: opacity 0.15s ease;
}
.btn-primary {
  background: var(--accent);
  color: var(--accent-fg);
}
.btn-primary:active { opacity: 0.85; }
.btn-ghost {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-ghost:active { background: var(--surface-2); }

/* Step page */
.step-container {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}
.step-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}
.step-progress {
  color: var(--text-dim);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
}
.step-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 24px 0;
}
.step-title {
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
  line-height: 1.1;
}
.step-desc {
  color: var(--text-dim);
  font-size: 17px;
  max-width: 32ch;
  margin: 0 0 36px;
}
.timer {
  margin-top: 12px;
}
.timer-display {
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
  font-size: 96px;
  font-weight: 300;
  letter-spacing: -0.04em;
  line-height: 1;
}
.timer.done .timer-display {
  color: var(--text);
  animation: pulse 0.6s ease-in-out 3;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.step-actions {
  display: grid;
  gap: 10px;
  padding-top: 24px;
}

/* Done */
.done-container {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
}
.done-title {
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 8px;
}
.done-sub {
  color: var(--text-dim);
  margin: 0 0 40px;
}
.done-container .btn { max-width: 320px; }

.empty {
  color: var(--text-dim);
  text-align: center;
  padding: 40px 0;
}
.empty code {
  background: var(--surface);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 14px;
}

@media (min-width: 720px) {
  .container { padding: 40px 24px 60px; }
  .step-title { font-size: 56px; }
  .timer-display { font-size: 128px; }
}