/* ==========================================================================
   ClassPanel.online — Modern Classroom Design System
   ========================================================================== */

:root {
  /* Color Palette - Light Mode Default */
  --bg-primary: #F8FAFC;
  --bg-surface: #FFFFFF;
  --bg-surface-subtle: #F1F5F9;
  --bg-card-hover: #F8FAFC;
  
  --border-color: #E2E8F0;
  --border-strong: #CBD5E1;
  
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --text-muted: #64748B;
  --text-inverse: #FFFFFF;
  
  /* Brand Accents */
  --primary: #4F46E5;
  --primary-hover: #4338CA;
  --primary-light: #EEF2FF;
  --primary-text: #4338CA;
  
  --accent-purple: #7C3AED;
  --accent-purple-light: #F5F3FF;
  
  --accent-emerald: #059669;
  --accent-emerald-light: #ECFDF5;
  
  --accent-sky: #0284C7;
  --accent-sky-light: #F0F9FF;
  
  --accent-amber: #D97706;
  --accent-amber-light: #FFFBEB;
  
  --accent-rose: #E11D48;
  --accent-rose-light: #FFF1F2;

  --accent-coral: #F97316;
  --accent-coral-light: #FFF7ED;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
  --shadow-glow: 0 0 25px rgba(79, 70, 229, 0.25);

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-slow: 0.4s cubic-bezier(0.16, 1, 0.3, 1);

  /* Projector specific */
  --tool-bg: #FFFFFF;
  --tool-border: #E2E8F0;
  --digit-color: #0F172A;
}

/* Dark Mode Theme */
[data-theme="dark"] {
  --bg-primary: #090D16;
  --bg-surface: #111827;
  --bg-surface-subtle: #1F2937;
  --bg-card-hover: #1E293B;
  
  --border-color: #1F2937;
  --border-strong: #374151;
  
  --text-primary: #F8FAFC;
  --text-secondary: #CBD5E1;
  --text-muted: #94A3B8;
  --text-inverse: #0F172A;

  --primary: #6366F1;
  --primary-hover: #818CF8;
  --primary-light: #1E1B4B;
  --primary-text: #A5B4FC;

  --accent-purple: #8B5CF6;
  --accent-purple-light: #2E1065;

  --accent-emerald: #10B981;
  --accent-emerald-light: #064E3B;

  --accent-sky: #38BDF8;
  --accent-sky-light: #082F49;

  --accent-amber: #F59E0B;
  --accent-amber-light: #451A03;

  --accent-rose: #F43F5E;
  --accent-rose-light: #4C0519;

  --accent-coral: #FB923C;
  --accent-coral-light: #431407;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 35px rgba(99, 102, 241, 0.35);

  --tool-bg: #111827;
  --tool-border: #1F2937;
  --digit-color: #F8FAFC;
}

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

html {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary);
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  text-decoration: underline;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  outline: none;
  background: none;
}

/* Accessibility Focus */
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

/* Global Container */
.container {
  width: 100%;
  max-width: 1240px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

/* Site Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

[data-theme="dark"] .site-header {
  background: rgba(17, 24, 39, 0.88);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.25rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.brand-logo:hover {
  text-decoration: none;
}

.brand-icon {
  width: 2.35rem;
  height: 2.35rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

.brand-badge {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.2rem 0.5rem;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: var(--radius-full);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.action-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  height: 2.6rem;
  padding: 0 0.9rem;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.875rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.action-btn:hover {
  background: var(--bg-surface-subtle);
  border-color: var(--border-strong);
  transform: translateY(-1px);
}

.action-btn-icon {
  width: 2.6rem;
  padding: 0;
}

.btn-primary {
  background: var(--primary);
  color: #FFFFFF;
  border: 1px solid var(--primary);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--primary-hover);
  color: #FFFFFF;
  border-color: var(--primary-hover);
}

/* Category Pills on Home */
.category-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1.1rem;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 700;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  background: var(--bg-surface);
  color: var(--text-secondary);
  box-shadow: var(--shadow-sm);
}

.category-pill.active {
  background: var(--primary);
  color: #FFFFFF;
  border-color: var(--primary);
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

/* Tool Grid Cards */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.tool-card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.6rem;
  text-decoration: none;
  color: inherit;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.tool-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--card-accent, var(--primary));
  opacity: 0.8;
}

.tool-card:hover {
  text-decoration: none;
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--card-accent, var(--primary));
}

.tool-card-icon {
  width: 3.4rem;
  height: 3.4rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  margin-bottom: 1.2rem;
  background: var(--card-light, var(--primary-light));
  color: var(--card-accent, var(--primary));
  transition: transform var(--transition-fast);
}

.tool-card:hover .tool-card-icon {
  transform: scale(1.08) rotate(2deg);
}

.tool-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.tool-card-desc {
  font-size: 0.925rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.tool-card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
}

.tool-card-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  background: var(--card-light, var(--primary-light));
  color: var(--card-accent, var(--primary));
}

/* Tool Interactive Shell (Full Width Top Container) */
.tool-stage-wrapper {
  padding: 1.75rem 0 2.5rem;
}

.tool-stage {
  background: var(--tool-bg);
  border: 1px solid var(--tool-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  padding: 2.25rem;
  position: relative;
  transition: all var(--transition-normal);
}

.tool-stage.is-fullscreen {
  position: fixed !important;
  top: 0 !important;
  left: 0 !important;
  right: 0 !important;
  bottom: 0 !important;
  width: 100vw !important;
  height: 100vh !important;
  z-index: 9999 !important;
  border-radius: 0 !important;
  border: none !important;
  padding: 2rem !important;
  display: flex !important;
  flex-direction: column !important;
  justify-content: center !important;
  align-items: center !important;
  background: var(--bg-surface) !important;
  overflow: auto !important;
}

.tool-header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  gap: 1rem;
  flex-wrap: wrap;
}

.tool-title-group h1 {
  font-size: 1.85rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.tool-title-subtitle {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

.tool-control-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

/* Fullscreen Projector Button */
.btn-projector {
  background: #0F172A;
  color: #FFFFFF;
  border-radius: var(--radius-full);
  padding: 0.5rem 1.1rem;
  font-size: 0.85rem;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  transition: all var(--transition-fast);
}

[data-theme="dark"] .btn-projector {
  background: #3B82F6;
  color: #FFFFFF;
}

.btn-projector:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.35);
}

/* Giant Digital Display (Classroom Timer, Clocks, etc.) */
.timer-big-display {
  font-size: clamp(4.5rem, 15vw, 10.5rem);
  font-weight: 900;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  letter-spacing: -0.04em;
  text-align: center;
  line-height: 1;
  margin: 1.5rem 0;
  color: var(--digit-color);
  user-select: none;
  font-variant-numeric: tabular-nums;
  text-shadow: 0 2px 10px rgba(0,0,0,0.05);
  transition: color 0.3s ease;
}

/* Dynamic Progress Bar */
.timer-progress-track {
  width: 100%;
  height: 14px;
  background: var(--bg-surface-subtle);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin: 1.25rem 0 2rem;
  border: 1px solid var(--border-color);
}

.timer-progress-fill {
  height: 100%;
  width: 100%;
  background: var(--accent-emerald);
  border-radius: var(--radius-full);
  transition: width 0.3s linear, background-color 0.4s ease;
}

.timer-progress-fill.warning {
  background: var(--accent-amber);
}

.timer-progress-fill.danger {
  background: var(--accent-rose);
  animation: pulse-danger 1s infinite alternate;
}

@keyframes pulse-danger {
  from { opacity: 0.85; filter: brightness(1); }
  to { opacity: 1; filter: brightness(1.2); }
}

/* Big Action Buttons (Touch Friendly) */
.timer-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.btn-giant {
  min-width: 140px;
  height: 4rem;
  padding: 0 2rem;
  font-size: 1.35rem;
  font-weight: 800;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  transition: all var(--transition-normal);
  user-select: none;
}

.btn-giant:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: var(--shadow-lg);
}

.btn-giant:active {
  transform: translateY(0) scale(0.98);
}

.btn-giant-primary {
  background: var(--accent-emerald);
  color: #FFFFFF;
  box-shadow: 0 8px 20px rgba(5, 150, 105, 0.35);
}

.btn-giant-primary.is-running {
  background: var(--accent-amber);
  box-shadow: 0 8px 20px rgba(217, 119, 6, 0.35);
}

.btn-giant-secondary {
  background: var(--bg-surface-subtle);
  border: 2px solid var(--border-strong);
  color: var(--text-primary);
}

.btn-giant-secondary:hover {
  background: var(--border-color);
}

/* Quick Preset Chips */
.presets-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin: 1.25rem 0;
}

.preset-chip {
  padding: 0.5rem 1.1rem;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 700;
  border: 1px solid var(--border-color);
  background: var(--bg-surface-subtle);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.preset-chip:hover {
  background: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-1px);
}

/* Content SEO Sections Below the Fold */
.seo-content-section {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-color);
  margin-top: 2rem;
}

.seo-content-grid {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 3rem;
  align-items: start;
}

@media (max-width: 860px) {
  .seo-content-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

.seo-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.seo-card h2 {
  font-size: 1.45rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.9rem;
  color: var(--text-primary);
}

.seo-card p {
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1rem;
  font-size: 1rem;
}

.seo-features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.seo-features-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.5;
}

.seo-features-list li svg {
  flex-shrink: 0;
  color: var(--accent-emerald);
  margin-top: 0.2rem;
}

/* Related Tools Section */
.related-tools-section {
  padding: 2.5rem 0 3.5rem;
  border-top: 1px solid var(--border-color);
}

.section-heading {
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Footer */
.site-footer {
  margin-top: auto;
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 3.5rem 0 2rem;
  color: var(--text-secondary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

.footer-brand p {
  margin-top: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  max-width: 320px;
  line-height: 1.5;
}

.footer-col h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-col a {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-col a:hover {
  color: var(--primary);
}

.footer-bottom {
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 1rem;
}

/* Modal Dialog (Class Rosters, Settings, Quick Search) */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
  padding: 1rem;
}

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

.modal-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 580px;
  max-height: 90vh;
  overflow-y: auto;
  padding: 2rem;
  transform: translateY(12px) scale(0.98);
  transition: transform var(--transition-normal);
}

.modal-backdrop.is-open .modal-card {
  transform: translateY(0) scale(1);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.modal-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
}

.modal-close-btn {
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 1.25rem;
  transition: background var(--transition-fast);
}

.modal-close-btn:hover {
  background: var(--bg-surface-subtle);
  color: var(--text-primary);
}

/* Form inputs */
.input-text, .select-input, .textarea-input {
  width: 100%;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  border: 1.5px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.95rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input-text:focus, .select-input:focus, .textarea-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}

/* Confetti Canvas */
#confetti-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 10000;
}

/* Custom scrollbars */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-surface-subtle);
}

::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}