/* CampusEvents Modern Design System (WCAG AA Compliant, Mobile-First) */
:root {
  --primary: #1d4ed8;
  --primary-hover: #1e40af;
  --primary-light: #eff6ff;
  --secondary: #475569;
  --secondary-hover: #334155;
  --success: #15803d;
  --success-bg: #f0fdf4;
  --warning: #b45309;
  --warning-bg: #fffbeb;
  --danger: #b91c1c;
  --danger-hover: #991b1b;
  --danger-bg: #fef2f2;
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --border: #e2e8f0;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --focus-ring: 0 0 0 3px rgba(29, 78, 216, 0.4);
  --radius: 8px;
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --primary: #3b82f6;
    --primary-hover: #60a5fa;
    --primary-light: #1e293b;
    --secondary: #94a3b8;
    --secondary-hover: #cbd5e1;
    --success: #4ade80;
    --success-bg: #064e3b;
    --warning: #fbbf24;
    --warning-bg: #78350f;
    --danger: #f87171;
    --danger-hover: #ef4444;
    --danger-bg: #7f1d1d;
    --bg-main: #0b0f19;
    --bg-card: #131b2e;
    --border: #1e293b;
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
  }
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary);
  color: #ffffff;
  padding: 8px 16px;
  z-index: 1000;
  text-decoration: none;
  font-weight: 600;
  border-radius: 0 0 var(--radius) 0;
}
.skip-link:focus {
  top: 0;
}

/* Header & Nav */
.navbar {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 12px 24px;
  position: sticky;
  top: 0;
  z-index: 50;
}
.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}
.brand {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
.brand-tag {
  font-size: 0.75rem;
  background-color: var(--primary-light);
  color: var(--primary);
  padding: 2px 8px;
  border-radius: 12px;
  font-weight: 600;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 16px;
  list-style: none;
}
.nav-links a {
  text-decoration: none;
  color: var(--text-main);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 6px 10px;
  border-radius: var(--radius);
  transition: background 0.15s ease;
}
.nav-links a:hover, .nav-links a:focus-visible {
  background-color: var(--primary-light);
  color: var(--primary);
  outline: none;
}
.user-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-muted);
  background: var(--primary-light);
  padding: 4px 10px;
  border-radius: 20px;
}

/* Main Container */
.main-content {
  flex: 1;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 24px 16px;
}

/* Toast Container */
.toast-container {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 10px;
  pointer-events: none;
}
.toast {
  pointer-events: auto;
  padding: 12px 20px;
  border-radius: var(--radius);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  font-size: 0.95rem;
  font-weight: 500;
  min-width: 280px;
  max-width: 420px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  animation: slideIn 0.25s ease-out;
}
@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}
.toast-success { background: var(--success-bg); color: var(--success); border: 1px solid var(--success); }
.toast-warning { background: var(--warning-bg); color: var(--warning); border: 1px solid var(--warning); }
.toast-danger  { background: var(--danger-bg);  color: var(--danger);  border: 1px solid var(--danger); }
.toast-info    { background: var(--primary-light); color: var(--primary); border: 1px solid var(--primary); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius);
  cursor: pointer;
  text-decoration: none;
  border: 1px solid transparent;
  transition: all 0.15s ease-in-out;
  gap: 8px;
}
.btn:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}
.btn-primary {
  background-color: var(--primary);
  color: #ffffff;
}
.btn-primary:hover:not(:disabled) {
  background-color: var(--primary-hover);
}
.btn-outline {
  background-color: transparent;
  border-color: var(--border);
  color: var(--text-main);
}
.btn-outline:hover:not(:disabled) {
  background-color: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
}
.btn-danger {
  background-color: var(--danger);
  color: #ffffff;
}
.btn-danger:hover:not(:disabled) {
  background-color: var(--danger-hover);
}
.btn:disabled, .btn[aria-disabled="true"] {
  opacity: 0.55;
  cursor: not-allowed;
  filter: grayscale(40%);
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 9999px;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.badge-open { background: var(--success-bg); color: var(--success); border: 1px solid var(--success); }
.badge-waitlist { background: var(--warning-bg); color: var(--warning); border: 1px solid var(--warning); }
.badge-full { background: var(--danger-bg); color: var(--danger); border: 1px solid var(--danger); }
.badge-past { background: var(--border); color: var(--text-muted); }

/* Event Cards Grid */
.events-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
  margin-top: 24px;
}
.event-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.event-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}
.event-banner {
  width: 100%;
  height: 180px;
  object-fit: cover;
  background-color: var(--border);
}
.event-body {
  padding: 20px;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.event-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.event-society {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.event-title {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 8px;
}
.event-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  flex: 1;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.event-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border);
  padding-top: 14px;
  margin-top: auto;
}
.spots-indicator {
  font-size: 0.9rem;
  font-weight: 600;
}
.spots-left {
  color: var(--success);
}
.spots-zero {
  color: var(--danger);
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 64px 20px;
  background: var(--bg-card);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  margin-top: 32px;
}
.empty-state h3 {
  font-size: 1.35rem;
  margin-bottom: 8px;
}
.empty-state p {
  color: var(--text-muted);
  max-width: 480px;
  margin: 0 auto 20px auto;
}

/* Detail Page */
.detail-container {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  max-width: 860px;
  margin: 0 auto;
}
.detail-banner {
  width: 100%;
  max-height: 380px;
  object-fit: cover;
}
.detail-content {
  padding: 32px;
}
.detail-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.detail-info-row {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  padding: 16px;
  background: var(--primary-light);
  border-radius: var(--radius);
  margin-bottom: 24px;
}
.info-item {
  display: flex;
  flex-direction: column;
}
.info-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 700;
}
.info-value {
  font-size: 1.05rem;
  font-weight: 600;
}
.ai-summary-card {
  margin: 24px 0;
  padding: 18px;
  background: var(--primary-light);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius) var(--radius) 0;
}
.ai-badge {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  margin-bottom: 6px;
}

/* Forms */
.form-container {
  max-width: 640px;
  margin: 0 auto;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}
.form-group {
  margin-bottom: 20px;
}
.form-label {
  display: block;
  font-weight: 600;
  margin-bottom: 6px;
  font-size: 0.95rem;
}
.form-control {
  width: 100%;
  padding: 10px 14px;
  font-size: 0.95rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
  color: var(--text-main);
  font-family: inherit;
}
.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: var(--focus-ring);
}
.form-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  background: var(--bg-card);
  padding: 20px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: auto;
}