:root {
  --bg-1: #0a0a14;
  --bg-2: #111122;
  --card-bg: rgba(22, 22, 40, 0.75);
  --card-border: rgba(80, 80, 160, 0.25);
  --accent: #6c5ce7;
  --accent-bright: #a29bfe;
  --accent-dim: rgba(108, 92, 231, 0.35);
  --success: #00b894;
  --text-primary: #e8e8f0;
  --text-secondary: #9090a8;
  --ring-bg: rgba(80, 80, 120, 0.15);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg-1);
  color: var(--text-primary);
  overflow-x: hidden;
}

body {
  background: radial-gradient(ellipse at top, var(--bg-2) 0%, var(--bg-1) 70%);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 20px;
}

.app {
  width: 100%;
  max-width: 460px;
}

.timer-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 24px;
  padding: 36px 32px;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.05);
  text-align: center;
}

.title {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-bright) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 24px;
}

.duration-selector {
  margin-bottom: 28px;
}

.selector-label {
  display: block;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.preset-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-bottom: 14px;
}

.preset-btn {
  padding: 8px 14px;
  border-radius: 10px;
  border: 1px solid transparent;
  background: rgba(80, 80, 120, 0.12);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.preset-btn:hover {
  background: rgba(108, 92, 231, 0.15);
  color: var(--text-primary);
}

.preset-btn.active {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent-bright);
}

.custom-duration {
  display: flex;
  gap: 8px;
  justify-content: center;
  align-items: center;
}

.custom-input {
  width: 130px;
  padding: 8px 12px;
  border-radius: 10px;
  border: 1px solid rgba(80, 80, 120, 0.25);
  background: rgba(80, 80, 120, 0.1);
  color: var(--text-primary);
  font-size: 13px;
  outline: none;
  transition: border-color 0.2s ease;
}

.custom-input::placeholder {
  color: var(--text-secondary);
  opacity: 0.6;
}

.custom-input:focus {
  border-color: var(--accent);
}

.set-custom-btn {
  padding: 8px 16px;
  border-radius: 10px;
  border: none;
  background: var(--accent-dim);
  color: var(--accent-bright);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.set-custom-btn:hover {
  background: var(--accent);
  color: white;
}

.timer-display-container {
  position: relative;
  width: 260px;
  height: 260px;
  margin: 0 auto 8px;
}

.timer-ring {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.ring-bg {
  fill: none;
  stroke: var(--ring-bg);
  stroke-width: 6;
}

.ring-progress {
  fill: none;
  stroke: var(--accent);
  stroke-width: 6;
  stroke-linecap: round;
  stroke-dasharray: 565.48;
  stroke-dashoffset: 565.48;
  transition: stroke-dashoffset 0.3s ease, stroke 0.3s ease;
  filter: drop-shadow(0 0 6px var(--accent-dim));
}

.ring-progress.completed {
  stroke: var(--success);
  filter: drop-shadow(0 0 8px rgba(0, 184, 148, 0.4));
}

.time-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 48px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

.status-label {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 20px;
  min-height: 20px;
  transition: color 0.3s ease;
}

.status-label.running {
  color: var(--accent-bright);
}

.status-label.paused {
  color: #ffeaa7;
}

.status-label.completed {
  color: var(--success);
}

.controls {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-bottom: 28px;
}

.btn {
  padding: 14px 32px;
  border-radius: 14px;
  border: none;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  letter-spacing: 0.01em;
}

.btn:active {
  transform: scale(0.97);
}

.btn-start {
  background: linear-gradient(135deg, var(--accent) 0%, #8b7cf6 100%);
  color: white;
  box-shadow: 0 4px 16px var(--accent-dim);
}

.btn-start:hover {
  box-shadow: 0 4px 24px var(--accent);
  transform: translateY(-1px);
}

.btn-reset {
  background: rgba(80, 80, 120, 0.15);
  color: var(--text-secondary);
  border: 1px solid rgba(80, 80, 120, 0.25);
}

.btn-reset:hover {
  background: rgba(80, 80, 120, 0.25);
  color: var(--text-primary);
}

.session-counter {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding-top: 20px;
  border-top: 1px solid rgba(80, 80, 120, 0.15);
}

.counter-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}

.counter-value {
  font-size: 32px;
  font-weight: 800;
  color: var(--accent-bright);
  font-variant-numeric: tabular-nums;
}

.footer-note {
  text-align: center;
  font-size: 12px;
  color: var(--text-secondary);
  opacity: 0.5;
  margin-top: 16px;
}

@media (max-width: 480px) {
  .timer-card {
    padding: 24px 20px;
  }
  .timer-display-container {
    width: 220px;
    height: 220px;
  }
  .time-text {
    font-size: 40px;
  }
}