:root {
  --bg-color: #0b0f19;
  --card-bg: #131b2e;
  --card-border: #1e293b;
  --card-hover: #1e2945;
  --accent: #3b82f6;
  --accent-light: #60a5fa;
  --accent-glow: rgba(59, 130, 246, 0.15);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --badge-bg: #1e293b;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --radius: 14px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh;
}

.app-container {
  max-width: 860px;
  margin: 0 auto;
  padding: 18px 16px 40px;
}

/* Header */
.main-header {
  margin-bottom: 20px;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
}

.badge-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent-light);
  background: var(--accent-glow);
  padding: 3px 10px;
  border-radius: 20px;
  border: 1px solid rgba(59, 130, 246, 0.25);
  margin-bottom: 6px;
}

.header-title h1 {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #fff;
}

.time-now {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text-muted);
  border-radius: 10px;
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  transition: var(--transition);
}

.btn-ghost:hover {
  color: #fff;
  border-color: var(--accent);
  background: var(--card-hover);
}

/* Bot Card Promo */
.bot-card {
  display: flex;
  align-items: center;
  gap: 16px;
  background: linear-gradient(135deg, rgba(30, 58, 138, 0.45) 0%, rgba(15, 23, 42, 0.6) 100%);
  border: 1px solid rgba(59, 130, 246, 0.35);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 22px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25);
}

.bot-card-icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 16px rgba(59, 130, 246, 0.4);
}

.bot-card-text h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.bot-card-text p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.bot-card-text code {
  background: rgba(255, 255, 255, 0.1);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent-light);
  font-size: 0.85rem;
}

/* Navigation tabs */
.view-switch {
  display: flex;
  background: #0f172a;
  padding: 4px;
  border-radius: 12px;
  border: 1px solid var(--card-border);
  margin-bottom: 20px;
  gap: 4px;
}

.tab-btn {
  flex: 1;
  padding: 10px 14px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: 9px;
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
}

.tab-btn:hover {
  color: #fff;
}

.tab-btn.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.35);
}

/* Day Header Card */
.day-header-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 18px;
  margin-bottom: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.day-header-info h2 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 2px;
}

.day-header-info .date-sub {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.day-timing-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.25);
  padding: 6px 12px;
  border-radius: 8px;
}

.day-override-banner {
  width: 100%;
  margin-top: 8px;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.day-override-banner.modified {
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: #fbbf24;
}

.day-override-banner.canceled {
  background: rgba(239, 68, 68, 0.12);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: #f87171;
}

/* Lessons List */
.lessons-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.lesson-card {
  display: grid;
  grid-template-columns: 85px 1fr auto;
  align-items: center;
  gap: 16px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 16px;
  transition: var(--transition);
}

.lesson-card:hover {
  border-color: #334155;
  transform: translateY(-1px);
}

.lesson-card.active-now {
  border-color: var(--accent);
  background: linear-gradient(90deg, rgba(59, 130, 246, 0.12) 0%, var(--card-bg) 100%);
  box-shadow: 0 0 15px rgba(59, 130, 246, 0.15);
}

.lesson-time-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: #0f172a;
  border: 1px solid var(--card-border);
  padding: 10px 8px;
  border-radius: 10px;
  text-align: center;
}

.lesson-number {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent-light);
  line-height: 1.1;
}

.lesson-number-label {
  font-size: 0.65rem;
  text-transform: uppercase;
  color: var(--text-dim);
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}

.lesson-interval {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-weight: 500;
  white-space: nowrap;
}

.lesson-details {
  overflow: hidden;
}

.lesson-subject {
  font-size: 1.05rem;
  font-weight: 600;
  color: #fff;
  margin-bottom: 4px;
  word-break: break-word;
}

.lesson-room-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 8px;
  background: #1e293b;
  border: 1px solid #334155;
  color: #e2e8f0;
  white-space: nowrap;
}

.lesson-room-badge.sport {
  background: rgba(16, 185, 129, 0.15);
  border-color: rgba(16, 185, 129, 0.3);
  color: #34d399;
}

/* Empty or Weekend State */
.empty-state {
  text-align: center;
  background: var(--card-bg);
  border: 1px dashed var(--card-border);
  border-radius: var(--radius);
  padding: 40px 20px;
}

.empty-state-icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
}

.empty-state h3 {
  font-size: 1.15rem;
  margin-bottom: 6px;
}

.empty-state p {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Week Grid View */
.week-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

.weekday-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 16px;
  display: flex;
  flex-direction: column;
}

.weekday-card.is-today {
  border-color: var(--accent);
  box-shadow: 0 0 16px rgba(59, 130, 246, 0.2);
}

.weekday-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--card-border);
  margin-bottom: 12px;
}

.weekday-card-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
}

.weekday-card-header .timing {
  font-size: 0.78rem;
  color: #38bdf8;
  font-weight: 600;
}

.weekday-lessons {
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex-grow: 1;
}

.mini-lesson {
  display: grid;
  grid-template-columns: 28px 1fr auto;
  align-items: center;
  gap: 10px;
  background: #0f172a;
  padding: 8px 10px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.mini-num {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent-light);
  text-align: center;
}

.mini-subject {
  font-size: 0.85rem;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.mini-room {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  background: #1e293b;
  padding: 2px 6px;
  border-radius: 4px;
}

/* Slots Reference Section */
.slots-reference {
  margin-top: 28px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 16px;
}

.reference-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.reference-header h4 {
  font-size: 0.95rem;
  font-weight: 600;
}

.slot-badge {
  font-size: 0.72rem;
  color: var(--text-muted);
  background: #0f172a;
  padding: 2px 8px;
  border-radius: 6px;
}

.slots-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.slot-chip {
  background: #0f172a;
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.slot-chip b {
  color: var(--accent-light);
}

/* Loader */
.loader {
  text-align: center;
  padding: 60px 0;
  color: var(--text-muted);
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid rgba(255, 255, 255, 0.1);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 14px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Footer */
.main-footer {
  margin-top: 36px;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* Responsive Styles for Mobile */
@media (max-width: 600px) {
  .app-container {
    padding: 14px 12px 30px;
  }

  .header-title h1 {
    font-size: 1.35rem;
  }

  .lesson-card {
    grid-template-columns: 75px 1fr auto;
    padding: 12px;
    gap: 10px;
  }

  .lesson-number {
    font-size: 1rem;
  }

  .lesson-interval {
    font-size: 0.65rem;
  }

  .lesson-subject {
    font-size: 0.92rem;
  }

  .lesson-room-badge {
    padding: 4px 8px;
    font-size: 0.78rem;
  }

  .bot-card {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .week-grid {
    grid-template-columns: 1fr;
  }
}