:root {
  color-scheme: light;
  --bg: #f5f7fb;
  --card: #ffffff;
  --ink: #0f172a;
  --muted: #475569;
  --accent: #2563eb;
  --accent-soft: rgba(37, 99, 235, 0.1);
  --border: rgba(15, 23, 42, 0.08);
  --shadow: 0 25px 50px -25px rgba(15, 23, 42, 0.35);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background: radial-gradient(circle at top left, rgba(37, 99, 235, 0.12), transparent 55%),
    radial-gradient(circle at top right, rgba(14, 165, 233, 0.12), transparent 50%),
    var(--bg);
  min-height: 100vh;
}

header {
  padding: clamp(2rem, 5vw, 4rem);
  text-align: center;
}

header h1 {
  margin-bottom: 0.5rem;
  font-size: clamp(2.2rem, 6vw, 3.4rem);
}

header p {
  margin: 0 auto;
  max-width: 680px;
  color: var(--muted);
  font-size: 1.05rem;
}

main {
  padding: 0 clamp(1rem, 6vw, 4rem) 4rem;
}

.hero-actions {
  margin-top: 1.5rem;
  display: flex;
  justify-content: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.btn {
  border: none;
  border-radius: 999px;
  font-weight: 600;
  padding: 0.7rem 1.4rem;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn.primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 15px 35px -20px rgba(37, 99, 235, 1);
}

.btn.secondary {
  background: var(--accent-soft);
  color: var(--accent);
}

.btn.ghost {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--border);
}

#gen-auto-pr.active {
  background: var(--accent);
  color: #fff;
}

.mobile-landscape-tip {
  display: none;
  margin: 0;
  padding: 0.55rem 0.75rem;
  border-radius: 0.75rem;
  background: #fff7ed;
  border: 1px solid #fdba74;
  color: #9a3412;
  font-size: 0.86rem;
  font-weight: 600;
}

.btn:hover {
  transform: translateY(-1px);
}

.card {
  background: var(--card);
  border-radius: 1.25rem;
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.generator-container {
  margin: 0 auto;
  max-width: 1100px;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.generator-controls,
.generator-tools {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.generator-controls {
  justify-content: space-between;
}

.gen-filters {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #fff;
  padding: 6px 10px;
}

.gen-filters summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--ink);
}

.rhythm-category-toggles {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.6rem;
}

.category-checkbox {
  background: var(--accent-soft);
  color: var(--accent);
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.category-checkbox input {
  accent-color: var(--accent);
}

.generator-tools-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.generator-display {
  background: var(--card);
  border-radius: 1.1rem;
  padding: 1rem;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

#ecg-canvas {
  width: 100%;
  height: auto;
  border-radius: 0.75rem;
  background: #fff;
}

#ecg-canvas.measure-active {
  cursor: crosshair;
}

.generator-quiz {
  display: none;
}

.gen-opt-btn {
  display: block;
  width: 100%;
  text-align: left;
  margin-bottom: 0.6rem;
  padding: 0.65rem 0.8rem;
  border-radius: 0.8rem;
  border: 1px solid var(--border);
  background: #fff;
  font-weight: 600;
  cursor: pointer;
}

.gen-opt-btn.correct {
  border-color: #22c55e;
  background: rgba(34, 197, 94, 0.1);
}

.gen-opt-btn.incorrect {
  border-color: #ef4444;
  background: rgba(239, 68, 68, 0.1);
}

.gen-feedback {
  font-weight: 600;
  margin-top: 0.5rem;
}

.gen-feedback.correct { color: #15803d; }
.gen-feedback.incorrect { color: #b91c1c; }

.measure-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  gap: 0.4rem;
}

.measure-grid.compact {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.measure-grid.compact .measure-card {
  flex: 1 1 110px;
  min-width: 110px;
}

.measure-card {
  padding: 0.5rem 0.7rem;
  border-radius: 0.6rem;
  background: rgba(15, 23, 42, 0.04);
  text-align: center;
}

.measure-label {
  display: block;
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.measure-value {
  font-weight: 700;
  font-size: 1rem;
}

.gen-measure-readout {
  width: 100%;
}

.gen-info {
  font-size: 0.95rem;
  color: var(--muted);
}

.generator-stats,
.generator-log {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: space-between;
  align-items: center;
}

.generator-log-actions {
  display: flex;
  gap: 0.5rem;
}

footer {
  text-align: center;
  padding: 2rem;
  color: var(--muted);
}

@media (max-width: 720px) {
  .mobile-landscape-tip {
    display: block;
  }

  .generator-controls {
    flex-direction: column;
    align-items: stretch;
  }

  .generator-display {
    overflow-x: auto;
  }

  .rhythm-category-toggles {
    gap: 0.4rem;
  }

  .category-checkbox {
    min-height: 44px;
    padding: 0.55rem 0.8rem;
  }

  .generator-tools-row .btn {
    min-height: 44px;
  }

  .gen-zoom-label {
    width: 100%;
  }

  .generator-log-actions {
    flex-direction: column;
    width: 100%;
  }

  .generator-log-actions .btn {
    width: 100%;
    text-align: center;
  }
}

@media (max-width: 900px) and (orientation: landscape) {
  .mobile-landscape-tip {
    display: none;
  }

  .generator-display {
    overflow-x: hidden;
  }

  #ecg-canvas {
    width: 100% !important;
    height: auto !important;
    max-height: 140px;
  }
}