/* ==========================================================================
   BHS Prayagraj PYQ Archive - Minimalist & Scholastic Theme
   Colors: Deep Oxford Navy (#0B132B, #1C2541), Academic Gold (#D97706, #F59E0B),
   Slate Neutral (#F8FAFC, #FFFFFF), Crisp Slate Borders (#E2E8F0, #1E293B)
   ========================================================================== */

:root {
  --bg-primary: #0a0f1d;
  --bg-surface: #111827;
  --bg-card: #172033;
  --bg-card-hover: #1e2942;
  --border-subtle: #1f293d;
  --border-focus: #d97706;
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --brand-navy: #0f2042;
  --brand-gold: #f59e0b;
  --brand-gold-dark: #d97706;
  --brand-gold-glow: rgba(245, 158, 11, 0.15);
  
  --status-success: #10b981;
  --status-warning: #f59e0b;
  --status-danger: #ef4444;
  --status-info: #3b82f6;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --font-serif: 'Cinzel', Georgia, serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1240px;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-surface: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --border-subtle: #e2e8f0;
  --border-focus: #b45309;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --brand-navy: #1e3a8a;
  --brand-gold: #d97706;
  --brand-gold-dark: #b45309;
  --brand-gold-glow: rgba(217, 119, 6, 0.12);
}

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

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

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 15, 29, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  transition: var(--transition);
}

[data-theme="light"] .site-header {
  background: rgba(255, 255, 255, 0.85);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
  color: inherit;
}

.brand-crest {
  width: 44px;
  height: 44px;
  filter: drop-shadow(0 2px 8px var(--brand-gold-glow));
}

.brand-text h1 {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text-primary);
  line-height: 1.2;
}

.brand-text p {
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--brand-gold);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.55rem 1.1rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
  outline: none;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--brand-gold) 0%, var(--brand-gold-dark) 100%);
  color: #0b132b;
  box-shadow: 0 2px 10px var(--brand-gold-glow);
}

.btn-primary:hover {
  transform: translateY(-1px);
  filter: brightness(1.08);
  box-shadow: 0 4px 15px var(--brand-gold-glow);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border-color: var(--border-subtle);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--text-secondary);
}

.btn-icon {
  padding: 0.55rem;
  border-radius: var(--radius-md);
  background: var(--bg-card);
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

.btn-icon:hover {
  color: var(--text-primary);
  background: var(--bg-card-hover);
}

/* Hero Section */
.hero {
  padding: 3rem 1.5rem 2rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 650px;
  height: 350px;
  background: radial-gradient(circle, var(--brand-gold-glow) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
}

.hero-inner {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.25);
  color: var(--brand-gold);
  font-size: 0.78rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: 2.35rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 0.85rem;
  color: var(--text-primary);
}

.hero-title span {
  background: linear-gradient(135deg, #fcd34d 0%, #f59e0b 50%, #d97706 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 1.75rem;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 1.5rem;
  border-top: 1px solid var(--border-subtle);
  padding-top: 1.25rem;
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--brand-gold);
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Main Layout */
.main-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem;
  width: 100%;
  flex: 1;
}

/* Filter Bar */
.filter-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  margin-bottom: 2rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.filter-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr auto;
  gap: 1rem;
  align-items: end;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.form-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.input, .select {
  width: 100%;
  padding: 0.6rem 0.85rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.875rem;
  outline: none;
  transition: var(--transition);
}

.input:focus, .select:focus {
  border-color: var(--brand-gold);
  box-shadow: 0 0 0 3px var(--brand-gold-glow);
}

/* Papers Grid */
.papers-section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
}

.section-title {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
}

.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}

.paper-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.paper-card:hover {
  transform: translateY(-3px);
  border-color: rgba(245, 158, 11, 0.4);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
}

.paper-card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 0.85rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-sm);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
}

.badge-class {
  background: rgba(59, 130, 246, 0.15);
  color: #60a5fa;
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.badge-term {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.badge-verified {
  background: rgba(16, 185, 129, 0.15);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-flagged {
  background: rgba(239, 68, 68, 0.15);
  color: #f87171;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.paper-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}

.paper-meta {
  font-size: 0.82rem;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  margin-bottom: 1.25rem;
}

.meta-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.paper-card-actions {
  display: flex;
  gap: 0.6rem;
  border-top: 1px solid var(--border-subtle);
  padding-top: 0.85rem;
  margin-top: auto;
}

.paper-card-actions .btn {
  flex: 1;
}

/* Modals */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(5, 8, 18, 0.8);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.modal-backdrop.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-container {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 650px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 20px 45px rgba(0, 0, 0, 0.5);
  transform: translateY(20px) scale(0.98);
  transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-backdrop.active .modal-container {
  transform: translateY(0) scale(1);
}

.modal-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
}

.modal-close {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  line-height: 1;
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 1.5rem;
}

.modal-footer {
  padding: 1.25rem 1.5rem;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

/* Upload Tabs */
.upload-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 0.5rem;
}

.tab-btn {
  padding: 0.5rem 1rem;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.tab-btn.active {
  color: var(--brand-gold);
  background: var(--brand-gold-glow);
}

/* Dropzone */
.dropzone {
  border: 2px dashed var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 2.25rem 1.5rem;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  background: var(--bg-card);
}

.dropzone:hover, .dropzone.dragover {
  border-color: var(--brand-gold);
  background: var(--brand-gold-glow);
}

.dropzone-icon {
  font-size: 2.5rem;
  color: var(--brand-gold);
  margin-bottom: 0.75rem;
}

.dropzone-text {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}

.dropzone-sub {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* Camera Scanner & Buffer */
.camera-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  align-items: center;
}

.camera-preview-wrapper {
  position: relative;
  width: 100%;
  max-width: 480px;
  height: 280px;
  background: #000;
  border-radius: var(--radius-md);
  overflow: hidden;
}

#camera-video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.camera-guide-overlay {
  position: absolute;
  inset: 16px;
  border: 2px dashed rgba(245, 158, 11, 0.6);
  border-radius: var(--radius-sm);
  pointer-events: none;
}

.camera-controls {
  display: flex;
  gap: 0.75rem;
  width: 100%;
  justify-content: center;
}

/* Staging Buffer */
.staging-buffer {
  margin-top: 1.25rem;
  padding: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
}

.buffer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.buffer-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--brand-gold);
}

.buffer-thumbnails {
  display: flex;
  gap: 0.75rem;
  overflow-x: auto;
  padding-bottom: 0.5rem;
}

.thumbnail-item {
  position: relative;
  width: 80px;
  height: 110px;
  flex-shrink: 0;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  overflow: hidden;
  background: #000;
}

.thumbnail-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.thumbnail-page-num {
  position: absolute;
  bottom: 2px;
  left: 2px;
  background: rgba(0, 0, 0, 0.7);
  font-size: 0.65rem;
  color: #fff;
  padding: 1px 4px;
  border-radius: 3px;
}

.thumbnail-remove {
  position: absolute;
  top: 2px;
  right: 2px;
  background: rgba(239, 68, 68, 0.85);
  color: white;
  border: none;
  border-radius: 50%;
  width: 18px;
  height: 18px;
  font-size: 0.7rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

/* AI Verification Card */
.ai-status-card {
  padding: 1rem;
  border-radius: var(--radius-md);
  margin-top: 1.25rem;
  display: flex;
  gap: 0.85rem;
  align-items: flex-start;
  font-size: 0.85rem;
}

.ai-status-card.pending {
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  color: #93c5fd;
}

.ai-status-card.success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #6ee7b7;
}

.ai-status-card.flagged {
  background: rgba(245, 158, 11, 0.12);
  border: 1px solid rgba(245, 158, 11, 0.35);
  color: #fde68a;
}

.ai-status-card.rejected {
  background: rgba(239, 68, 68, 0.12);
  border: 1px solid rgba(239, 68, 68, 0.35);
  color: #fca5a5;
}

.ai-icon-spin {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* Footer */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  padding: 2rem 1.5rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition);
}

.footer-links a:hover {
  color: var(--brand-gold);
}

/* Responsive */
@media (max-width: 860px) {
  .filter-grid {
    grid-template-columns: 1fr 1fr;
  }
  .filter-grid .form-group:first-child {
    grid-column: span 2;
  }
  .hero-title {
    font-size: 1.85rem;
  }
}

@media (max-width: 540px) {
  .filter-grid {
    grid-template-columns: 1fr;
  }
  .filter-grid .form-group:first-child {
    grid-column: span 1;
  }
  .hero-stats {
    flex-direction: column;
    gap: 0.75rem;
  }
  .header-actions .btn-text {
    display: none;
  }
}