:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #14141f;
  --bg-tertiary: #1e1e2e;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  --accent: #00d4ff;
  --accent-secondary: #00ff88;
  --danger: #ff4466;
  --focus-ring: #00d4ff;
  --focus-glow: rgba(0, 212, 255, 0.4);
  --radius-md: 12px;
}

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

html, body {
  width: 600px; height: 600px; overflow: hidden;
  background: #000;
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

#app { width: 100%; height: 100%; position: relative; }

.screen {
  width: 100%; height: 100%; position: absolute; top: 0; left: 0;
  display: flex; flex-direction: column;
}
.screen.hidden { display: none; }

.focusable {
  transition: all 0.15s ease;
  border: 2px solid transparent;
  cursor: pointer;
  outline: none;
}
.focusable:focus {
  border-color: var(--focus-ring);
  box-shadow: 0 0 20px var(--focus-glow);
}
.hidden { display: none !important; }

/* ---------- Header ---------- */
.header {
  flex: 0 0 auto;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--bg-tertiary);
}
.title {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 3px;
  color: var(--text-primary);
}
.delta-badge {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent);
  background: var(--bg-tertiary);
  padding: 6px 16px;
  border-radius: var(--radius-md);
  font-variant-numeric: tabular-nums;
}
.hint {
  font-size: 13px;
  letter-spacing: 1px;
  color: var(--text-muted);
  font-weight: 600;
}

/* ---------- Cards ---------- */
.cards {
  flex: 0 0 auto;
  display: flex;
  align-items: stretch;
  gap: 12px;
  padding: 18px 20px 10px;
  height: 232px;
}
.zone-card {
  flex: 1;
  background: var(--bg-secondary);
  border-radius: 18px;
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  text-align: left;
  font-family: inherit;
  border: 2px solid transparent;
}
.zone-card:focus {
  background: var(--bg-tertiary);
  border-color: var(--accent);
  box-shadow: 0 0 24px var(--focus-glow);
}
.zone-label {
  font-size: 12px;
  letter-spacing: 2px;
  color: var(--text-muted);
  font-weight: 700;
}
.zone-city {
  font-size: 24px;
  font-weight: 600;
  color: var(--text-primary);
  margin-top: 6px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.zone-time {
  font-size: 58px;
  font-weight: 200;
  color: var(--accent);
  line-height: 1;
  margin-top: auto;
  font-variant-numeric: tabular-nums;
  letter-spacing: -1px;
}
.zone-meta {
  font-size: 14px;
  color: var(--text-secondary);
  margin-top: 10px;
}
.card-link {
  flex: 0 0 auto;
  align-self: center;
  font-size: 32px;
  color: var(--text-muted);
  font-weight: 300;
}

/* ---------- Slider ---------- */
.slider-section {
  flex: 0 0 auto;
  padding: 6px 30px 4px;
}
.slider-info {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}
.slider-label {
  font-size: 12px;
  letter-spacing: 2px;
  color: var(--text-muted);
  font-weight: 700;
}
.slider-value {
  font-size: 20px;
  font-weight: 700;
  color: var(--accent-secondary);
  font-variant-numeric: tabular-nums;
}
.slider-track {
  position: relative;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 3px;
  margin: 16px 0 8px;
}
.slider-tick {
  position: absolute;
  top: -4px;
  width: 2px;
  height: 14px;
  background: #2a2a3e;
  transform: translateX(-50%);
}
.slider-fill {
  position: absolute;
  top: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-secondary), var(--accent));
  border-radius: 3px;
  transition: left 0.18s ease, width 0.18s ease;
}
.slider-thumb {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  background: var(--accent);
  border: 2px solid #001a22;
  border-radius: 50%;
  transform: translate(-50%, -50%);
  box-shadow: 0 0 14px rgba(0, 212, 255, 0.7);
  transition: left 0.18s ease;
}
.slider-scale {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 1px;
  font-variant-numeric: tabular-nums;
}

/* ---------- Controls ---------- */
.controls {
  flex: 0 0 auto;
  display: flex;
  gap: 8px;
  padding: 12px 20px 6px;
  justify-content: center;
}
.ctrl-btn {
  flex: 1;
  max-width: 104px;
  height: 60px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  font-size: 18px;
  font-weight: 600;
  font-family: inherit;
  font-variant-numeric: tabular-nums;
}
.ctrl-btn.primary {
  color: var(--accent);
  background: var(--bg-tertiary);
}
.ctrl-btn:focus {
  background: var(--bg-tertiary);
  border-color: var(--accent);
  box-shadow: 0 0 16px var(--focus-glow);
  color: var(--accent);
}

/* ---------- Bottom / Swap ---------- */
.bottom {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  padding: 6px 20px 14px;
}
.swap-btn {
  width: 100%;
  height: 56px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 2px;
  font-family: inherit;
}
.swap-btn:focus {
  background: var(--bg-tertiary);
  border-color: var(--accent);
  box-shadow: 0 0 16px var(--focus-glow);
  color: var(--accent);
}

/* ---------- Picker ---------- */
.picker-list {
  flex: 1 1 auto;
  overflow-y: auto;
  padding: 14px 20px 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.picker-list::-webkit-scrollbar { width: 6px; }
.picker-list::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 3px;
}
.picker-item {
  flex: 0 0 auto;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  padding: 0 20px;
  font-family: inherit;
  text-align: left;
}
.picker-item:focus {
  background: var(--bg-tertiary);
  border-color: var(--accent);
  box-shadow: 0 0 18px var(--focus-glow);
}
.picker-item .city {
  font-size: 19px;
  font-weight: 500;
  color: var(--text-primary);
}
.picker-item .time {
  font-size: 19px;
  font-weight: 500;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}
.picker-item.current {
  background: rgba(0, 212, 255, 0.08);
}
.picker-item.current .city::before {
  content: '\25CF\00a0\00a0';
  color: var(--accent-secondary);
  font-size: 12px;
  vertical-align: middle;
}