:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --success: #16a34a;
  --success-light: #f0fdf4;
  --warning: #d97706;
  --warning-light: #fffbeb;
  --danger: #dc2626;
  --danger-light: #fef2f2;
  --text-main: #1f2937;
  --text-muted: #6b7280;
  --bg-page: #f9fafb;
  --bg-card: #ffffff;
  --border-color: #e5e7eb;
  --border-focus: #3b82f6;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

[data-theme="dark"] {
  --primary: #3b82f6;
  --primary-hover: #60a5fa;
  --primary-light: #1e3a5f;
  --success: #22c55e;
  --success-light: #14532d;
  --warning: #f59e0b;
  --warning-light: #78350f;
  --danger: #ef4444;
  --danger-light: #7f1d1d;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --bg-page: #0f172a;
  --bg-card: #1e293b;
  --border-color: #334155;
  --border-focus: #60a5fa;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.6), 0 4px 6px -2px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* Header & Navigation Bar */
.navbar {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
}

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.75rem 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-brand:hover {
  text-decoration: none;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.nav-icon-btn,
.hamburger-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  min-width: 38px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background-color: var(--bg-card);
  color: var(--text-main);
  cursor: pointer;
  font-size: 1.15rem;
  transition: all 0.15s ease;
  padding: 0;
  box-shadow: var(--shadow-sm);
  user-select: none;
}

.nav-icon-btn:hover,
.hamburger-btn:hover {
  background-color: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
}

.hamburger-btn {
  display: none;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.nav-link {
  color: var(--text-muted);
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
}
.nav-link:hover, .nav-link.active {
  color: var(--primary);
  background-color: var(--primary-light);
  text-decoration: none;
}

/* Mobile Hamburger Menu */
@media (max-width: 768px) {
  .hamburger-btn {
    display: block;
  }
  .nav-menu {
    display: none;
    flex-direction: column;
    width: 100%;
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem;
    box-shadow: var(--shadow-md);
    gap: 0.5rem;
  }
  .nav-menu.is-active {
    display: flex;
  }
  .nav-link {
    width: 100%;
    display: block;
    padding: 0.6rem 1rem;
  }
}

/* Main Container */
.main-content {
  flex: 1;
  max-width: 1100px;
  width: 100%;
  margin: 1.5rem auto;
  padding: 0 1rem;
}

/* Flash Messages */
.flash-messages {
  margin-bottom: 1.5rem;
}
.alert {
  padding: 0.85rem 1.25rem;
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.alert-success {
  background-color: var(--success-light);
  color: var(--success);
  border: 1px solid #bbf7d0;
}
.alert-danger {
  background-color: var(--danger-light);
  color: var(--danger);
  border: 1px solid #fecaca;
}
.alert-warning {
  background-color: var(--warning-light);
  color: var(--warning);
  border: 1px solid #fde68a;
}
.alert-info {
  background-color: var(--primary-light);
  color: var(--primary);
  border: 1px solid #bfdbfe;
}

/* Timezone Banner */
.timezone-banner {
  background-color: #f0fdfa;
  border: 1px solid #99f6e4;
  color: #0f766e;
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.9rem;
}
.tz-selector-inline {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.tz-select {
  padding: 0.3rem 0.5rem;
  border: 1px solid #0f766e;
  border-radius: var(--radius-sm);
  background-color: #fff;
  color: #0f766e;
  font-size: 0.85rem;
}

/* Cards */
.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}
.card-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.75rem;
  margin-bottom: 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.card-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-main);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 1.1rem;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s ease;
  text-decoration: none;
}
.btn:hover {
  text-decoration: none;
}
.btn-primary {
  background-color: var(--primary);
  color: #fff;
}
.btn-primary:hover {
  background-color: var(--primary-hover);
}
.btn-secondary {
  background-color: #fff;
  border-color: var(--border-color);
  color: var(--text-main);
}
.btn-secondary:hover {
  background-color: #f3f4f6;
}
.btn-danger {
  background-color: var(--danger);
  color: #fff;
}
.btn-danger:hover {
  background-color: #b91c1c;
}
.btn-sm {
  padding: 0.35rem 0.75rem;
  font-size: 0.85rem;
}
.btn-block {
  width: 100%;
}
.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Forms */
.form-group {
  margin-bottom: 1.25rem;
}
.form-label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  color: var(--text-main);
}
.form-label .optional {
  font-weight: 400;
  color: var(--text-muted);
}
.form-control {
  width: 100%;
  padding: 0.6rem 0.85rem;
  font-size: 0.95rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: #fff;
  color: var(--text-main);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.form-control:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}
textarea.form-control {
  resize: vertical;
  min-height: 80px;
}
.form-help {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* PoW CAPTCHA Widget */
.captcha-container {
  background-color: #f8fafc;
  border: 1px solid #cbd5e1;
  border-radius: var(--radius-md);
  padding: 0.85rem 1rem;
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.captcha-status {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.88rem;
  color: var(--text-muted);
}
.captcha-spinner {
  width: 16px;
  height: 16px;
  border: 2px solid #cbd5e1;
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
.captcha-badge-success {
  color: var(--success);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Calendar Layout */
.calendar-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}
@media (min-width: 860px) {
  .calendar-layout {
    grid-template-columns: 1.2fr 0.8fr;
  }
}

.calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}
.calendar-month-title {
  font-size: 1.15rem;
  font-weight: 700;
}
.calendar-nav-buttons {
  display: flex;
  gap: 0.5rem;
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 4px;
}
.calendar-weekday {
  text-align: center;
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text-muted);
  padding: 0.5rem 0;
  text-transform: uppercase;
}
.calendar-day {
  background-color: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  min-height: 52px;
  padding: 4px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
  transition: all 0.15s ease;
  position: relative;
}
.calendar-day:hover:not(.other-month):not(.disabled) {
  border-color: var(--primary);
  background-color: var(--primary-light);
}
.calendar-day.selected {
  border-color: var(--primary);
  background-color: var(--primary-light);
  box-shadow: 0 0 0 2px var(--primary);
}
.calendar-day.today {
  font-weight: 700;
  border-color: #93c5fd;
}
.calendar-day.other-month {
  background-color: #f3f4f6;
  color: #9ca3af;
  cursor: default;
}
.calendar-day.disabled {
  background-color: #f9fafb;
  color: #d1d5db;
  cursor: not-allowed;
}
.day-num {
  font-size: 0.85rem;
  font-weight: 500;
  margin-left: 2px;
}
.day-slots-badge {
  background-color: #dcfce7;
  color: #15803d;
  font-size: 0.72rem;
  font-weight: 600;
  border-radius: 9999px;
  padding: 1px 6px;
  align-self: flex-start;
  margin-top: 2px;
}

/* Slots List Panel */
.slots-panel {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
}
.slots-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}
.slots-container {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-height: 420px;
  overflow-y: auto;
}
.slot-pill {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #fff;
  border: 1px solid var(--border-color);
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.15s ease;
}
.slot-pill:hover {
  border-color: var(--primary);
  background-color: var(--primary-light);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}
.slot-pill-time {
  font-weight: 600;
  font-size: 0.95rem;
}
.slot-pill-duration {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
}
.table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}
.table th, .table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color);
}
.table th {
  background-color: #f8fafc;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
}
.table tr:hover td {
  background-color: #f8fafc;
}

/* Status Badges */
.badge {
  display: inline-block;
  padding: 0.2rem 0.55rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 9999px;
  text-transform: uppercase;
}
.badge-available { background-color: #dcfce7; color: #166534; }
.badge-pending { background-color: #fef3c7; color: #92400e; }
.badge-confirmed { background-color: #dbeafe; color: #1e40af; }
.badge-cancelled { background-color: #f3f4f6; color: #6b7280; }

/* Footer */
.app-footer {
  margin-top: auto;
  background-color: var(--bg-card);
  border-top: 1px solid var(--border-color);
  padding: 1rem 0;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
}
.footer-content {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.footer-separator {
  color: #cbd5e1;
}

/* Dark Mode Component Overrides */
[data-theme="dark"] .card {
  background-color: var(--bg-card);
  border-color: var(--border-color);
}

[data-theme="dark"] .form-control {
  background-color: #0f172a;
  border-color: var(--border-color);
  color: var(--text-main);
}
[data-theme="dark"] .form-control:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.25);
}

[data-theme="dark"] .btn-secondary {
  background-color: var(--bg-card);
  border-color: var(--border-color);
  color: var(--text-main);
}
[data-theme="dark"] .btn-secondary:hover {
  background-color: #334155;
  border-color: #475569;
}

[data-theme="dark"] .timezone-banner {
  background-color: #042f2e;
  border-color: #115e59;
  color: #5eead4;
}
[data-theme="dark"] .timezone-banner strong {
  color: #a7f3d0;
}
[data-theme="dark"] .tz-select {
  background-color: #0f172a;
  border-color: #115e59;
  color: #5eead4;
}

[data-theme="dark"] .calendar-day {
  background-color: var(--bg-card);
  border-color: var(--border-color);
}
[data-theme="dark"] .calendar-day:hover:not(.other-month):not(.disabled) {
  border-color: var(--primary);
  background-color: var(--primary-light);
}
[data-theme="dark"] .calendar-day.selected {
  border-color: var(--primary);
  background-color: var(--primary-light);
  box-shadow: 0 0 0 2px var(--primary);
}
[data-theme="dark"] .calendar-day.today {
  border-color: #60a5fa;
}
[data-theme="dark"] .calendar-day.other-month {
  background-color: #0b1120;
  color: #475569;
}
[data-theme="dark"] .day-slots-badge {
  background-color: #14532d;
  color: #86efac;
}

[data-theme="dark"] .slots-panel {
  background-color: var(--bg-card);
  border-color: var(--border-color);
}
[data-theme="dark"] .slot-pill {
  background-color: var(--bg-card);
  border-color: var(--border-color);
}
[data-theme="dark"] .slot-pill:hover {
  border-color: var(--primary);
  background-color: var(--primary-light);
}

[data-theme="dark"] .captcha-container {
  background-color: #0f172a;
  border-color: var(--border-color);
}
[data-theme="dark"] .captcha-spinner {
  border-color: #334155;
  border-top-color: var(--primary);
}
[data-theme="dark"] .captcha-status {
  color: var(--text-muted);
}

[data-theme="dark"] .table th {
  background-color: #0f172a;
  color: var(--text-muted);
}
[data-theme="dark"] .table tr:hover td {
  background-color: #273549;
}

[data-theme="dark"] .alert-success {
  background-color: #052e16;
  color: #86efac;
  border-color: #166534;
}
[data-theme="dark"] .alert-danger {
  background-color: #450a0a;
  color: #fca5a5;
  border-color: #991b1b;
}
[data-theme="dark"] .alert-warning {
  background-color: #451a03;
  color: #fcd34d;
  border-color: #92400e;
}
[data-theme="dark"] .alert-info {
  background-color: #172554;
  color: #93c5fd;
  border-color: #1e40af;
}

[data-theme="dark"] .badge-available { background-color: #14532d; color: #86efac; }
[data-theme="dark"] .badge-pending { background-color: #78350f; color: #fde68a; }
[data-theme="dark"] .badge-confirmed { background-color: #1e3a8a; color: #bfdbfe; }
[data-theme="dark"] .badge-cancelled { background-color: #334155; color: #94a3b8; }

[data-theme="dark"] code {
  background-color: #334155 !important;
  color: #f1f5f9 !important;
}

[data-theme="dark"] select option {
  background-color: #1e293b;
  color: #f1f5f9;
}

/* Days of Week Box (Dark mode native) */
.days-of-week-box {
  background-color: var(--bg-page);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  display: flex;
  gap: 0.85rem;
  flex-wrap: wrap;
  color: var(--text-main);
}
.days-of-week-box label {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.9rem;
  cursor: pointer;
  color: var(--text-main);
}

/* Modals */
.modal-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(2px);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}
.modal-backdrop.is-active {
  display: flex;
}
.modal-dialog {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 580px;
  max-height: 90vh;
  overflow-y: auto;
  padding: 1.5rem;
  position: relative;
}
.modal-close-btn {
  background: none;
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  color: var(--text-muted);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  line-height: 1;
}
.modal-close-btn:hover {
  color: var(--text-main);
  background-color: var(--primary-light);
}

/* Admin Calendar Month View */
.admin-calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}
.admin-calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 6px;
  margin-top: 0.5rem;
}
.admin-cal-day {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  min-height: 110px;
  padding: 6px;
  display: flex;
  flex-direction: column;
  cursor: pointer;
  transition: border-color 0.15s ease, background-color 0.15s ease;
  position: relative;
  user-select: none;
}
.admin-cal-day:hover:not(.other-month) {
  border-color: var(--primary);
  box-shadow: var(--shadow-sm);
}
.admin-cal-day.today {
  border-color: #3b82f6;
  box-shadow: 0 0 0 1px #3b82f6;
}
.admin-cal-day.other-month {
  background-color: var(--bg-page);
  opacity: 0.45;
  cursor: default;
}
.admin-day-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}
.admin-day-num {
  font-size: 0.88rem;
  font-weight: 600;
}
.admin-day-quick-add {
  opacity: 0;
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid var(--primary);
  border-radius: var(--radius-sm);
  width: 22px;
  height: 22px;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: opacity 0.15s ease;
}
.admin-cal-day:hover .admin-day-quick-add {
  opacity: 1;
}
.admin-day-slots-list {
  display: flex;
  flex-direction: column;
  gap: 3px;
  overflow-y: auto;
  max-height: 120px;
}
.admin-slot-pill {
  font-size: 0.76rem;
  font-weight: 500;
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 4px;
  transition: transform 0.1s ease;
}
.admin-slot-pill:hover {
  transform: scale(1.02);
}
.admin-slot-available {
  background-color: #dcfce7;
  color: #15803d;
  border-color: #bbf7d0;
}
.admin-slot-pending {
  background-color: #fef3c7;
  color: #b45309;
  border-color: #fde68a;
}
.admin-slot-confirmed {
  background-color: #dbeafe;
  color: #1d4ed8;
  border-color: #bfdbfe;
}

[data-theme="dark"] .admin-slot-available {
  background-color: #14532d;
  color: #86efac;
  border-color: #166534;
}
[data-theme="dark"] .admin-slot-pending {
  background-color: #78350f;
  color: #fde68a;
  border-color: #92400e;
}
[data-theme="dark"] .admin-slot-confirmed {
  background-color: #1e3a8a;
  color: #bfdbfe;
  border-color: #1d4ed8;
}