:root {
  color-scheme: dark light;
  --bg-color: #0b0d10;
  --panel-color: rgba(15, 19, 26, 0.85);
  --accent: #4fd1c5;
  --accent-strong: #38b2ac;
  --text-color: #f5f7fa;
  --text-muted: rgba(245, 247, 250, 0.7);
  --border-color: rgba(79, 209, 197, 0.3);
  --danger-color: #f56565;
  --font-body: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-title: 'Space Grotesk', 'Inter', sans-serif;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  --radius: 16px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  background: radial-gradient(circle at top right, rgba(79, 209, 197, 0.18), transparent 40%),
    radial-gradient(circle at bottom left, rgba(56, 178, 172, 0.15), transparent 35%),
    var(--bg-color);
  color: var(--text-color);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
}

body:focus-visible {
  outline: none;
}

.app {
  width: min(1100px, 100%);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  background: linear-gradient(135deg, rgba(17, 24, 39, 0.95), rgba(17, 24, 39, 0.7));
  border: 1px solid rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(16px);
  border-radius: var(--radius);
  padding: clamp(1.5rem, 1.5vw + 1rem, 2.5rem);
  box-shadow: var(--shadow);
}

.app-header,
.app-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.title-group h1 {
  margin: 0;
  font-family: var(--font-title);
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.subtitle {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.controls-group {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.control-item {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.volume-control input[type="range"] {
  width: 140px;
  accent-color: var(--accent);
}

.volume-value {
  align-self: flex-end;
  font-variant-numeric: tabular-nums;
  color: var(--text-color);
}

.checkbox {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  color: var(--text-color);
}

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

.pill-button {
  border: 1px solid rgba(79, 209, 197, 0.5);
  background: transparent;
  color: var(--text-color);
  padding: 0.35rem 0.9rem;
  border-radius: 999px;
  font-weight: 600;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all 0.2s ease;
}

.pill-button:hover,
.pill-button:focus-visible {
  border-color: var(--accent);
  background: rgba(79, 209, 197, 0.2);
  outline: none;
}

.control-button {
  border: none;
  border-radius: 12px;
  background: rgba(79, 209, 197, 0.12);
  color: var(--text-color);
  padding: 0.65rem 1.4rem;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.2s ease;
}

.control-button:hover,
.control-button:focus-visible {
  transform: translateY(-1px);
  background: rgba(79, 209, 197, 0.25);
  outline: 2px solid transparent;
  box-shadow: 0 0 0 3px rgba(79, 209, 197, 0.3);
}

.control-button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.controls-panel {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  background: rgba(13, 17, 23, 0.5);
  border-radius: var(--radius);
  padding: 1.5rem;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.primary-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.chime-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  color: var(--text-muted);
}

.chime-controls .control-label {
  font-size: 0.9rem;
}

.status-panel {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.5rem;
  border-radius: var(--radius);
  background: rgba(13, 17, 23, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.section-info {
  max-width: 260px;
}

.section-name {
  margin: 0;
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.next-section {
  margin: 0.3rem 0 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.timer-display {
  font-family: var(--font-title);
  font-size: clamp(3rem, 10vw, 5.5rem);
  letter-spacing: 0.08em;
  text-align: center;
  padding: 0.7rem 1.5rem;
  border-radius: 18px;
  background: linear-gradient(135deg, rgba(79, 209, 197, 0.18), rgba(79, 209, 197, 0));
  border: 1px solid rgba(79, 209, 197, 0.35);
  min-width: 220px;
}

#timeDisplay.overtime {
  color: var(--danger-color);
}

.progress-panel {
  display: grid;
  gap: 0.75rem;
}

.progress-track {
  position: relative;
  height: 18px;
  border-radius: 999px;
  background: rgba(13, 17, 23, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.08);
  overflow: visible;
}

.progress-fill {
  position: absolute;
  inset: 0;
  width: 0%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--accent-strong));
  transition: width 0.25s ease;
}

.progress-track.overtime {
  box-shadow: 0 0 0 1px rgba(255, 107, 107, 0.35) inset;
}

.progress-track.overtime .progress-fill {
  background: linear-gradient(90deg, var(--danger-color), rgba(255, 107, 107, 0.85));
}

.progress-marker {
  position: absolute;
  top: -6px;
  width: 2px;
  height: 30px;
  background: rgba(255, 255, 255, 0.45);
  transform: translateX(-50%);
  transition: background 0.3s ease, box-shadow 0.3s ease;
}

.progress-marker.completed {
  background: var(--accent-strong);
  box-shadow: 0 0 0 2px rgba(79, 209, 197, 0.25);
}

.progress-marker.active {
  background: #fff;
  box-shadow: 0 0 12px rgba(79, 209, 197, 0.55);
}

.progress-track.overtime .progress-marker {
  background: rgba(255, 255, 255, 0.3);
}

.progress-marker-labels {
  position: relative;
  min-height: 1.5rem;
}

.progress-marker-label {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-muted);
  white-space: nowrap;
  padding: 0.2rem 0.5rem;
  background: rgba(13, 17, 23, 0.7);
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  transition: color 0.3s ease, border-color 0.3s ease, background 0.3s ease;
}

.progress-marker-label.align-start {
  transform: translateX(0);
}

.progress-marker-label.align-end {
  transform: translateX(-100%);
}

.progress-marker-label.completed {
  color: var(--accent-light);
  border-color: rgba(79, 209, 197, 0.45);
}

.progress-marker-label.active {
  color: #fff;
  border-color: rgba(255, 255, 255, 0.6);
  background: rgba(79, 209, 197, 0.25);
}

.settings-panel {
  background: rgba(13, 17, 23, 0.5);
  border-radius: var(--radius);
  padding: 1.5rem;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.settings-panel h2 {
  margin: 0;
  font-size: 1.2rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.settings-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}

.settings-form {
  display: block;
}

.marker-list {
  display: grid;
  gap: 1rem;
}

.settings-row {
  display: grid;
  grid-template-columns: minmax(160px, 1fr) repeat(2, minmax(120px, 0.6fr)) auto;
  gap: 1rem;
  align-items: center;
  padding: 0.9rem 1rem;
  background: rgba(9, 12, 17, 0.7);
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.settings-label {
  font-weight: 600;
  letter-spacing: 0.04em;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.input-group label {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.input-group input {
  background: rgba(15, 19, 26, 0.9);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 10px;
  padding: 0.5rem;
  color: var(--text-color);
  font-size: 1rem;
  font-variant-numeric: tabular-nums;
}

.input-group input:focus-visible {
  outline: 2px solid var(--accent);
  border-color: var(--accent);
}

.message-area {
  min-height: 1.5rem;
  color: var(--danger-color);
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

.message-area.success {
  color: var(--accent);
}

.message-area.info {
  color: var(--text-muted);
}

.add-marker {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.add-marker:hover,
.add-marker:focus-visible {
  border-color: var(--accent);
  color: #fff;
}

.icon-button {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.08);
  color: var(--text-muted);
  border-radius: 999px;
  width: 2.25rem;
  height: 2.25rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  transition: border-color 0.2s ease, color 0.2s ease;
}

.icon-button:hover,
.icon-button:focus-visible {
  border-color: var(--accent);
  color: #fff;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 900px) {
  body {
    padding: 1.5rem;
  }

  .settings-row {
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  .settings-row .settings-label {
    grid-column: 1 / -1;
  }

  .settings-row .icon-button {
    justify-self: end;
    grid-column: 2 / 3;
  }

  .controls-group {
    flex-wrap: wrap;
    justify-content: flex-end;
  }

  .volume-control input[type="range"] {
    width: 120px;
  }
}

@media (max-width: 640px) {
  body {
    padding: 1rem;
  }

  .app {
    padding: 1.3rem;
  }

  .controls-group {
    width: 100%;
    justify-content: space-between;
  }

  .controls-panel,
  .status-panel,
  .settings-panel {
    padding: 1.1rem;
  }

  .timer-display {
    width: 100%;
  }

  .progress-track {
    height: 14px;
  }

  .progress-marker {
    top: -5px;
    height: 26px;
  }

  .progress-marker-labels {
    min-height: 2rem;
  }

  .progress-marker-label {
    font-size: 0.68rem;
    padding: 0.18rem 0.4rem;
  }

  .settings-row {
    grid-template-columns: 1fr;
    gap: 0.7rem;
  }

  .settings-row .icon-button {
    grid-column: 1 / -1;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}