/* ============================================
   Atomic Models Lesson — ED633 TMA2
   Shared stylesheet (Arabic / RTL)
   ============================================ */

/* ===== Dark theme (default) ===== */
:root,
:root[data-theme="dark"] {
  --bg-deep: #0a0e27;
  --bg-card: #141b3d;
  --accent-blue: #4a9eff;
  --accent-gold: #ffd700;
  --accent-purple: #9d4edd;
  --text-primary: #f0f4ff;
  --text-secondary: #a0aec0;
  --success: #48bb78;
  --danger: #f56565;

  --card-bg: rgba(20, 27, 61, 0.7);
  --card-border: rgba(74, 158, 255, 0.2);
  --card-border-hover: rgba(74, 158, 255, 0.5);
  --header-bg: rgba(10, 14, 39, 0.85);
  --header-border: rgba(74, 158, 255, 0.2);
  --code-bg: rgba(10, 14, 39, 0.8);
  --input-bg: rgba(10, 14, 39, 0.6);

  --bg-radial: radial-gradient(circle at 20% 10%, rgba(74, 158, 255, 0.12), transparent 40%),
               radial-gradient(circle at 80% 80%, rgba(157, 78, 221, 0.10), transparent 45%),
               radial-gradient(circle at 50% 50%, rgba(255, 215, 0, 0.04), transparent 60%);

  --shadow-glow-blue: 0 0 24px rgba(74, 158, 255, 0.35);
  --shadow-glow-gold: 0 0 24px rgba(255, 215, 0, 0.35);
  --shadow-glow-purple: 0 0 24px rgba(157, 78, 221, 0.35);

  --particle-color-1: rgba(74, 158, 255, 0.7);
  --particle-color-2: rgba(255, 215, 0, 0.6);
  --particle-color-3: rgba(157, 78, 221, 0.6);
  --particle-color-4: rgba(240, 244, 255, 0.5);
  --particle-line: rgba(74, 158, 255, 0.06);

  --radius-md: 14px;
  --radius-lg: 22px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Light theme — soft sky-blue ===== */
:root[data-theme="light"] {
  --bg-deep: #e6f1ff;
  --bg-card: #ffffff;
  --accent-blue: #2563eb;
  --accent-gold: #d97706;
  --accent-purple: #7c3aed;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --success: #16a34a;
  --danger: #dc2626;

  --card-bg: rgba(255, 255, 255, 0.78);
  --card-border: rgba(37, 99, 235, 0.18);
  --card-border-hover: rgba(37, 99, 235, 0.5);
  --header-bg: rgba(230, 241, 255, 0.85);
  --header-border: rgba(37, 99, 235, 0.18);
  --code-bg: rgba(15, 23, 42, 0.05);
  --input-bg: rgba(255, 255, 255, 0.85);

  --bg-radial: radial-gradient(circle at 20% 10%, rgba(37, 99, 235, 0.18), transparent 45%),
               radial-gradient(circle at 80% 80%, rgba(124, 58, 237, 0.13), transparent 45%),
               radial-gradient(circle at 50% 50%, rgba(217, 119, 6, 0.06), transparent 60%);

  --shadow-glow-blue: 0 0 24px rgba(37, 99, 235, 0.25);
  --shadow-glow-gold: 0 0 24px rgba(217, 119, 6, 0.25);
  --shadow-glow-purple: 0 0 24px rgba(124, 58, 237, 0.25);

  --particle-color-1: rgba(37, 99, 235, 0.55);
  --particle-color-2: rgba(217, 119, 6, 0.5);
  --particle-color-3: rgba(124, 58, 237, 0.5);
  --particle-color-4: rgba(15, 23, 42, 0.3);
  --particle-line: rgba(37, 99, 235, 0.08);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: 'Tajawal', 'Segoe UI', Tahoma, sans-serif;
  font-size: 1rem;
  line-height: 1.8;
  background: var(--bg-deep);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
  animation: fadeInBody 0.8s ease-out;
  transition: background 0.4s ease, color 0.4s ease;
}

@keyframes fadeInBody {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Background gradient overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: var(--bg-radial);
  pointer-events: none;
  z-index: -2;
  transition: background 0.4s ease;
}

#particle-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: -1;
  opacity: 0.6;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-family: 'Cairo', 'Tajawal', sans-serif;
  font-weight: 700;
  line-height: 1.4;
  background: linear-gradient(120deg, var(--accent-blue), var(--accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.6em;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.5rem; font-weight: 600; }
h4 { font-size: 1.2rem; }

p { margin-bottom: 1em; color: var(--text-primary); }

a {
  color: var(--accent-blue);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover { color: var(--accent-gold); }

/* ===== Layout ===== */
main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 100px 24px 60px;
  min-height: calc(100vh - 80px);
}

.section-title {
  text-align: center;
  margin-bottom: 2rem;
  position: relative;
  padding-bottom: 1rem;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  right: 50%;
  transform: translateX(50%);
  width: 80px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-gold));
  border-radius: 2px;
}

/* ===== Glassmorphism Card ===== */
.card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 1.5rem;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition), background 0.4s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--card-border-hover);
  box-shadow: var(--shadow-glow-blue);
}

.card.gold-tip {
  border-color: rgba(255, 215, 0, 0.3);
  background: linear-gradient(135deg, rgba(255, 215, 0, 0.08), var(--card-bg));
}
.card.gold-tip:hover { box-shadow: var(--shadow-glow-gold); border-color: rgba(255, 215, 0, 0.6); }

.card.purple-card { border-color: rgba(157, 78, 221, 0.3); }
.card.purple-card:hover { box-shadow: var(--shadow-glow-purple); border-color: rgba(157, 78, 221, 0.6); }

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
  font-size: 1rem;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  color: var(--text-primary);
  border: none;
  border-radius: 50px;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
  text-decoration: none;
  position: relative;
  overflow: hidden;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow-blue);
  color: var(--text-primary);
}

.btn-gold {
  background: linear-gradient(135deg, var(--accent-gold), #ffae00);
  color: var(--bg-deep);
}
.btn-gold:hover { box-shadow: var(--shadow-glow-gold); color: var(--bg-deep); }

.btn-outline {
  background: transparent;
  border: 2px solid var(--accent-blue);
  color: var(--accent-blue);
}
.btn-outline:hover { background: var(--accent-blue); color: var(--bg-deep); }

/* ===== Header ===== */
.site-header {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 100;
  background: var(--header-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--header-border);
  transition: background 0.4s ease;
}

.header-inner {
  max-width: 1300px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background: rgba(255, 255, 255, 0.92);
  border-radius: 10px;
  padding: 4px 12px;
  backdrop-filter: blur(4px);
}

.aou-logo {
  height: 42px;
  width: auto;
  max-width: 180px;
  object-fit: contain;
  display: block;
}

@media (min-width: 768px) {
  .aou-logo { height: 48px; max-width: 220px; }
}

/* Hero / cover page logo */
.aou-logo-hero {
  height: 70px;
  width: auto;
  max-width: 280px;
  object-fit: contain;
  margin: 0 auto 1.5rem;
  display: block;
  background: rgba(255, 255, 255, 0.92);
  border-radius: 14px;
  padding: 10px 20px;
  backdrop-filter: blur(4px);
}

@media (min-width: 768px) {
  .aou-logo-hero { height: 90px; max-width: 340px; }
}

.header-title {
  font-family: 'Cairo', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  background: linear-gradient(120deg, var(--accent-blue), var(--accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  text-align: center;
}

.menu-toggle {
  background: transparent;
  border: 1px solid var(--card-border-hover);
  border-radius: 10px;
  padding: 0.5rem 0.7rem;
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.menu-toggle:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-glow-blue);
}

.theme-toggle {
  background: transparent;
  border: 1px solid var(--card-border-hover);
  border-radius: 50%;
  width: 42px;
  height: 42px;
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.theme-toggle:hover {
  border-color: var(--accent-gold);
  box-shadow: var(--shadow-glow-gold);
  transform: rotate(20deg);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
}

@media (min-width: 768px) {
  .header-title { font-size: 1.4rem; }
}

/* ===== Side Panel ===== */
.side-panel {
  position: fixed;
  top: 0;
  left: -340px;
  width: 320px;
  max-width: 85vw;
  height: 100vh;
  background: var(--header-bg);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-left: 1px solid var(--card-border-hover);
  z-index: 200;
  padding: 5rem 1.5rem 2rem;
  overflow-y: auto;
  transition: left var(--transition), background 0.4s ease;
}

.side-panel.open { left: 0; }

.side-panel h3 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.side-panel ol {
  list-style: none;
  counter-reset: panel-counter;
}

.side-panel li {
  counter-increment: panel-counter;
  margin-bottom: 0.4rem;
}

.side-panel li a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 0.7rem;
  border-radius: 8px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: all var(--transition);
}

.side-panel li a::before {
  content: counter(panel-counter, decimal);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: rgba(74, 158, 255, 0.15);
  color: var(--accent-blue);
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
}

.side-panel li a:hover {
  background: rgba(74, 158, 255, 0.1);
  color: var(--accent-blue);
}

.side-panel li a.current {
  background: rgba(74, 158, 255, 0.2);
  color: var(--accent-gold);
}

.side-panel-close {
  position: absolute;
  top: 1rem;
  left: 1rem;
  background: transparent;
  border: 1px solid rgba(74, 158, 255, 0.3);
  color: var(--text-primary);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.overlay-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  z-index: 150;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
}

.overlay-backdrop.show {
  opacity: 1;
  pointer-events: auto;
}

/* ===== Footer ===== */
.site-footer {
  margin-top: 4rem;
  background: var(--header-bg);
  backdrop-filter: blur(10px);
  border-top: 1px solid var(--header-border);
  padding: 2.5rem 1.5rem 1.5rem;
  transition: background 0.4s ease;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.footer-col h4 {
  font-size: 1rem;
  margin-bottom: 0.8rem;
}

.footer-col p, .footer-col span {
  color: var(--text-secondary);
  font-size: 0.92rem;
}

.footer-nav {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.footer-nav .btn {
  padding: 0.5rem 1.2rem;
  font-size: 0.9rem;
}

.footer-bottom {
  text-align: center;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(74, 158, 255, 0.1);
  color: var(--text-secondary);
  font-size: 0.85rem;
}

@media (min-width: 768px) {
  .footer-inner { grid-template-columns: repeat(3, 1fr); }
}

/* ===== Floating Scroll Dots ===== */
.scroll-dots {
  position: fixed;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  display: none;
  flex-direction: column;
  gap: 12px;
  z-index: 50;
}

@media (min-width: 1024px) {
  .scroll-dots { display: flex; }
}

.scroll-dots .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(160, 174, 192, 0.3);
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
}

.scroll-dots .dot.active {
  background: var(--accent-gold);
  box-shadow: var(--shadow-glow-gold);
  transform: scale(1.4);
}

/* ===== Cover (index.html) ===== */
.hero {
  min-height: calc(100vh - 80px);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  padding: 6rem 1.5rem 3rem;
  position: relative;
}

.hero-title {
  font-size: 2rem;
  margin-bottom: 1rem;
  line-height: 1.3;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  max-width: 700px;
}

.atom-svg {
  width: 220px;
  height: 220px;
  margin: 1.5rem auto;
}

.student-info {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--card-border-hover);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 2rem auto;
  max-width: 520px;
  text-align: right;
  transition: background 0.4s ease;
}

.student-info-row {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  border-bottom: 1px dashed rgba(74, 158, 255, 0.15);
}

.student-info-row:last-child { border-bottom: none; }

.student-info-row strong {
  color: var(--accent-gold);
  font-family: 'Cairo', sans-serif;
}

.course-badge {
  display: inline-block;
  padding: 0.4rem 1rem;
  background: rgba(157, 78, 221, 0.2);
  border: 1px solid rgba(157, 78, 221, 0.4);
  border-radius: 50px;
  color: var(--accent-purple);
  font-family: 'Cairo', sans-serif;
  font-size: 0.85rem;
  margin-top: 1rem;
}

@media (min-width: 768px) {
  .hero-title { font-size: 3rem; }
  .hero-subtitle { font-size: 1.25rem; }
  .atom-svg { width: 300px; height: 300px; }
}

@media (min-width: 1024px) {
  .hero-title { font-size: 3.5rem; }
}

/* ===== Two-column model layout ===== */
.model-banner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 2rem;
  border-radius: var(--radius-lg);
  margin-bottom: 2rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.model-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--banner-start, var(--accent-blue)), var(--banner-end, var(--accent-purple)));
  opacity: 0.18;
  z-index: 0;
}

.model-banner > * { position: relative; z-index: 1; }

.model-banner .scientist {
  font-family: 'Cairo', sans-serif;
  font-size: 1.6rem;
  font-weight: 700;
  background: linear-gradient(120deg, var(--accent-blue), var(--accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.model-banner .year {
  display: inline-block;
  padding: 0.3rem 1rem;
  background: rgba(255, 215, 0, 0.15);
  border: 1px solid rgba(255, 215, 0, 0.3);
  border-radius: 50px;
  color: var(--accent-gold);
  font-family: 'Cairo', sans-serif;
  font-size: 0.95rem;
}

.model-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

@media (min-width: 1024px) {
  .model-grid { grid-template-columns: 60% 40%; }
}

.model-explanation {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  line-height: 1.9;
  transition: background 0.4s ease;
}

.model-illustration {
  display: flex;
  align-items: center;
  justify-content: center;
  background: radial-gradient(circle at center, rgba(74, 158, 255, 0.08), transparent 70%);
  border-radius: var(--radius-lg);
  padding: 1rem;
  min-height: 320px;
}

.model-illustration svg {
  width: 100%;
  max-width: 320px;
  height: auto;
}

/* ===== TOC Timeline ===== */
.toc-timeline {
  position: relative;
  margin: 3rem 0;
  padding: 1rem 0;
}

.toc-timeline::before {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  right: 50%;
  width: 3px;
  background: linear-gradient(180deg, var(--accent-blue), var(--accent-purple), var(--accent-gold));
  transform: translateX(50%);
  border-radius: 2px;
}

.toc-entry {
  display: flex;
  margin-bottom: 2rem;
  position: relative;
  width: 100%;
}

.toc-entry-content {
  width: 45%;
  padding: 1.2rem;
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}

.toc-entry-content:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-glow-blue);
  transform: scale(1.02);
}

.toc-entry-content h4 {
  margin-bottom: 0.4rem;
  font-size: 1.05rem;
}

.toc-entry-content p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin: 0;
}

.toc-entry.right { justify-content: flex-end; }
.toc-entry.left { justify-content: flex-start; }

.toc-entry::before {
  content: attr(data-num);
  position: absolute;
  right: 50%;
  transform: translateX(50%);
  top: 1rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-deep);
  border: 2px solid var(--accent-gold);
  color: var(--accent-gold);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
  font-size: 0.9rem;
  z-index: 2;
}

@media (max-width: 767px) {
  .toc-timeline::before { right: 20px; transform: none; }
  .toc-entry, .toc-entry.right, .toc-entry.left { justify-content: flex-start; padding-right: 50px; }
  .toc-entry-content { width: 100%; }
  .toc-entry::before { right: 4px; transform: none; }
}

/* ===== Hexagonal Objectives Grid ===== */
.hex-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin: 2rem 0;
}

@media (min-width: 600px) {
  .hex-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .hex-grid { grid-template-columns: repeat(3, 1fr); }
}

.hex {
  position: relative;
  aspect-ratio: 1 / 1.05;
  background: linear-gradient(135deg, rgba(74, 158, 255, 0.15), rgba(157, 78, 221, 0.15));
  clip-path: polygon(50% 0%, 100% 25%, 100% 75%, 50% 100%, 0% 75%, 0% 25%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  text-align: center;
  transition: transform var(--transition), filter var(--transition);
  border: none;
}

.hex::before {
  content: '';
  position: absolute;
  inset: 2px;
  background: var(--bg-card);
  clip-path: polygon(50% 0%, 100% 25%, 100% 75%, 50% 100%, 0% 75%, 0% 25%);
  z-index: 0;
}

.hex > * { position: relative; z-index: 1; }

.hex:hover {
  transform: rotate(2deg) scale(1.04);
  filter: drop-shadow(0 0 18px rgba(255, 215, 0, 0.4));
}

.hex .num {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-gold));
  color: var(--bg-deep);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.hex .level {
  font-size: 0.78rem;
  color: var(--accent-gold);
  font-family: 'Cairo', sans-serif;
  margin-bottom: 0.4rem;
}

.hex .text {
  font-size: 0.85rem;
  line-height: 1.5;
  margin-bottom: 0.6rem;
}

.hex .tool {
  font-size: 0.75rem;
  padding: 0.2rem 0.7rem;
  border-radius: 50px;
  background: rgba(74, 158, 255, 0.2);
  color: var(--accent-blue);
}

/* ===== Particles comparison cards ===== */
.particles-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin: 2rem 0;
}

@media (min-width: 768px) {
  .particles-grid { grid-template-columns: repeat(3, 1fr); }
}

.particle-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  text-align: center;
  transition: all var(--transition);
  opacity: 0;
  transform: translateY(20px);
}

.particle-card.visible {
  opacity: 1;
  transform: translateY(0);
}

.particle-card:hover {
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-glow-blue);
  transform: translateY(-6px);
}

.particle-symbol {
  font-size: 3.5rem;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.proton-color { color: var(--accent-gold); }
.neutron-color { color: var(--text-secondary); }
.electron-color { color: var(--accent-blue); }

.particle-name {
  font-family: 'Cairo', sans-serif;
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.particle-row {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  border-bottom: 1px dashed rgba(74, 158, 255, 0.15);
  font-size: 0.92rem;
}

.particle-row:last-child { border-bottom: none; }

.particle-row .label {
  color: var(--text-secondary);
}

.particle-row .value {
  color: var(--text-primary);
  font-weight: 600;
}

/* ===== Atomic Number/Mass Notation ===== */
.notation-display {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.2rem;
  font-family: 'Cairo', sans-serif;
  font-size: 5rem;
  margin: 2rem 0;
  color: var(--text-primary);
}

.notation-numbers {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  font-size: 1.8rem;
  line-height: 1.1;
}

.notation-numbers span {
  cursor: help;
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  transition: all var(--transition);
  position: relative;
}

.notation-numbers span:hover {
  background: rgba(74, 158, 255, 0.2);
  color: var(--accent-gold);
}

.notation-numbers .mass-num { color: var(--accent-gold); }
.notation-numbers .atomic-num { color: var(--accent-blue); }

.notation-symbol {
  font-size: 5rem;
  font-weight: 700;
  background: linear-gradient(120deg, var(--accent-blue), var(--accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.tooltip {
  position: absolute;
  bottom: -45px;
  right: 50%;
  transform: translateX(50%);
  background: var(--bg-deep);
  color: var(--text-primary);
  padding: 0.5rem 0.9rem;
  border-radius: 8px;
  border: 1px solid var(--accent-blue);
  font-size: 0.85rem;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
  z-index: 5;
}

.notation-numbers span:hover .tooltip {
  opacity: 1;
}

.code-block {
  background: var(--code-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  font-family: 'Consolas', 'Courier New', monospace;
  direction: ltr;
  text-align: left;
  margin: 1rem 0;
  overflow-x: auto;
  color: var(--text-primary);
}

.code-block .comment { color: var(--text-secondary); }
.code-block .keyword { color: var(--accent-gold); }
.code-block .value { color: var(--accent-blue); }

/* ===== Embed wrappers ===== */
.embed-wrapper {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  height: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid rgba(74, 158, 255, 0.3);
  margin: 1.5rem 0;
}

.embed-wrapper iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: none;
}

.embed-tall {
  position: relative;
  width: 100%;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--card-border-hover);
  margin: 1.5rem 0;
  background: var(--card-bg);
}

.embed-tall iframe {
  width: 100%;
  height: 600px;
  border: none;
  display: block;
}

.placeholder-embed {
  background: linear-gradient(135deg, rgba(74, 158, 255, 0.1), rgba(157, 78, 221, 0.1));
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  padding: 2rem;
}

.placeholder-embed-inner {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  text-align: center;
  padding: 2rem;
}

.placeholder-embed .icon {
  font-size: 4rem;
  margin-bottom: 1rem;
}

/* ===== Quiz ===== */
.quiz-container {
  max-width: 700px;
  margin: 2rem auto;
}

.quiz-progress {
  display: flex;
  gap: 6px;
  margin-bottom: 2rem;
}

.quiz-progress .step {
  flex: 1;
  height: 6px;
  border-radius: 3px;
  background: rgba(74, 158, 255, 0.2);
  transition: background var(--transition);
}

.quiz-progress .step.active { background: var(--accent-blue); }
.quiz-progress .step.done { background: var(--success); }

.quiz-question {
  margin-bottom: 1.5rem;
}

.quiz-question h3 {
  margin-bottom: 1.5rem;
  font-size: 1.25rem;
}

.quiz-options {
  display: grid;
  gap: 0.8rem;
}

.quiz-option {
  background: var(--card-bg);
  border: 2px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  cursor: pointer;
  transition: all var(--transition);
  text-align: right;
  font-family: inherit;
  font-size: 1rem;
  color: var(--text-primary);
}

.quiz-option:hover:not(.locked) {
  border-color: var(--accent-blue);
  transform: translateX(-4px);
}

.quiz-option.selected {
  border-color: var(--accent-blue);
  background: rgba(74, 158, 255, 0.1);
}

.quiz-option.correct {
  border-color: var(--success);
  background: rgba(72, 187, 120, 0.15);
}

.quiz-option.wrong {
  border-color: var(--danger);
  background: rgba(245, 101, 101, 0.15);
}

.quiz-option.locked { cursor: not-allowed; }

.quiz-feedback {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  display: none;
}

.quiz-feedback.correct {
  display: block;
  background: rgba(72, 187, 120, 0.1);
  border: 1px solid var(--success);
  color: var(--success);
}

.quiz-feedback.wrong {
  display: block;
  background: rgba(245, 101, 101, 0.1);
  border: 1px solid var(--danger);
  color: var(--danger);
}

.quiz-actions {
  margin-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.quiz-result {
  text-align: center;
  padding: 2rem;
}

.quiz-score {
  font-size: 4rem;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
  background: linear-gradient(120deg, var(--accent-blue), var(--accent-gold));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ===== AI Prompts ===== */
.prompt-card {
  background: var(--card-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--card-border-hover);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  position: relative;
  transition: background 0.4s ease;
}

.prompt-card .prompt-num {
  position: absolute;
  top: -16px;
  right: 1.5rem;
  background: linear-gradient(135deg, var(--accent-purple), var(--accent-blue));
  color: var(--text-primary);
  padding: 0.3rem 0.9rem;
  border-radius: 50px;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
  font-size: 0.85rem;
}

.prompt-text {
  background: var(--code-bg);
  padding: 1rem;
  border-radius: var(--radius-md);
  margin: 1rem 0;
  font-family: 'Tajawal', sans-serif;
  line-height: 1.8;
  border-right: 3px solid var(--accent-purple);
}

.copy-btn {
  background: rgba(74, 158, 255, 0.15);
  border: 1px solid var(--accent-blue);
  color: var(--accent-blue);
  padding: 0.5rem 1rem;
  border-radius: 50px;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.9rem;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.copy-btn:hover {
  background: var(--accent-blue);
  color: var(--bg-deep);
}

.copy-btn.copied {
  background: var(--success);
  color: var(--bg-deep);
  border-color: var(--success);
}

/* ===== References list ===== */
.references-list {
  list-style: none;
  counter-reset: ref-counter;
}

.references-list li {
  counter-increment: ref-counter;
  padding: 1rem 0 1rem 0;
  padding-right: 3rem;
  position: relative;
  border-bottom: 1px solid rgba(74, 158, 255, 0.1);
  text-indent: -2rem;
  margin-right: 2rem;
  line-height: 1.8;
}

.references-list li::before {
  content: counter(ref-counter) ".";
  position: absolute;
  right: 0;
  top: 1rem;
  color: var(--accent-gold);
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
}

/* ===== Misc utility ===== */
.text-center { text-align: center; }
.text-secondary { color: var(--text-secondary); }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-2 { margin-top: 1rem; }
.mt-4 { margin-top: 2rem; }

.icon-legend {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.icon-legend-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: var(--card-bg);
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--card-border);
}

.icon-legend-item .icon { font-size: 1.5rem; }

/* QR placeholder */
.qr-placeholder {
  width: 160px;
  height: 160px;
  background: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--bg-deep);
  font-family: 'Cairo', sans-serif;
  font-size: 0.85rem;
  margin: 1rem auto;
}

/* Steps list */
.steps-list {
  counter-reset: steps;
  list-style: none;
}

.steps-list li {
  counter-increment: steps;
  padding: 0.75rem 0 0.75rem 0;
  padding-right: 3rem;
  position: relative;
}

.steps-list li::before {
  content: counter(steps);
  position: absolute;
  right: 0;
  top: 0.6rem;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Cairo', sans-serif;
  font-weight: 700;
}

/* ===== AI Teacher Chat ===== */
.ai-chat {
  background: var(--card-bg);
  border: 1px solid var(--card-border-hover);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 1.5rem 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  min-height: 500px;
}

.ai-chat-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--card-border);
}

.ai-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-purple), var(--accent-blue));
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
  box-shadow: var(--shadow-glow-purple);
}

.ai-status {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.ai-status .dot-pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
  animation: pulse 1.6s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.3); }
}

.ai-messages {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  padding: 0.5rem;
  min-height: 320px;
  max-height: 500px;
}

.ai-msg {
  max-width: 85%;
  padding: 0.85rem 1.1rem;
  border-radius: 18px;
  line-height: 1.7;
  white-space: pre-wrap;
  word-wrap: break-word;
  animation: msgIn 0.3s ease-out;
}

@keyframes msgIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.ai-msg.assistant {
  align-self: flex-start;
  background: linear-gradient(135deg, rgba(74, 158, 255, 0.15), rgba(157, 78, 221, 0.15));
  border: 1px solid var(--card-border);
  border-bottom-right-radius: 4px;
}

.ai-msg.user {
  align-self: flex-end;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  color: #ffffff;
  border-bottom-left-radius: 4px;
}

.ai-msg.system-info {
  align-self: center;
  background: transparent;
  border: 1px dashed var(--card-border);
  color: var(--text-secondary);
  font-size: 0.85rem;
  text-align: center;
  max-width: 95%;
}

.ai-msg.error {
  align-self: stretch;
  background: rgba(245, 101, 101, 0.12);
  border: 1px solid var(--danger);
  color: var(--danger);
}

.ai-typing {
  display: inline-flex;
  gap: 4px;
  padding: 0.85rem 1.1rem;
  background: rgba(74, 158, 255, 0.12);
  border: 1px solid var(--card-border);
  border-radius: 18px;
  border-bottom-right-radius: 4px;
  align-self: flex-start;
}

.ai-typing span {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-blue);
  animation: typing 1.4s ease-in-out infinite;
}

.ai-typing span:nth-child(2) { animation-delay: 0.2s; }
.ai-typing span:nth-child(3) { animation-delay: 0.4s; }

@keyframes typing {
  0%, 100% { transform: translateY(0); opacity: 0.4; }
  50% { transform: translateY(-6px); opacity: 1; }
}

.ai-input-row {
  display: flex;
  gap: 0.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--card-border);
}

.ai-input {
  flex: 1;
  background: var(--input-bg);
  border: 1px solid var(--card-border);
  border-radius: 50px;
  padding: 0.75rem 1.25rem;
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1rem;
  transition: border-color var(--transition);
  resize: none;
  min-height: 48px;
  max-height: 120px;
  line-height: 1.5;
}

.ai-input:focus {
  outline: none;
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-glow-blue);
}

.ai-send {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  border: none;
  color: #fff;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  transition: all var(--transition);
  flex-shrink: 0;
}

.ai-send:hover:not(:disabled) {
  transform: scale(1.05);
  box-shadow: var(--shadow-glow-blue);
}

.ai-send:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.ai-config {
  background: var(--code-bg);
  border: 1px dashed var(--card-border);
  border-radius: var(--radius-md);
  padding: 1rem;
  margin-bottom: 1rem;
}

.ai-config label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.ai-config input[type="password"],
.ai-config input[type="text"] {
  width: 100%;
  background: var(--input-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 0.6rem 0.9rem;
  color: var(--text-primary);
  font-family: 'Consolas', monospace;
  font-size: 0.85rem;
  direction: ltr;
  text-align: left;
}

.ai-config input:focus {
  outline: none;
  border-color: var(--accent-blue);
}

.ai-suggestions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.ai-suggestion {
  background: rgba(74, 158, 255, 0.12);
  border: 1px solid var(--card-border);
  border-radius: 50px;
  padding: 0.4rem 1rem;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--accent-blue);
  font-family: inherit;
  transition: all var(--transition);
}

.ai-suggestion:hover {
  background: var(--accent-blue);
  color: #fff;
  border-color: var(--accent-blue);
}

/* ===== Print styles ===== */
@media print {
  body {
    background: white;
    color: black;
  }

  body::before, #particle-canvas, .site-header, .site-footer,
  .scroll-dots, .side-panel, .overlay-backdrop, .menu-toggle {
    display: none !important;
  }

  main {
    padding: 0;
    max-width: 100%;
  }

  .card, .model-explanation, .particle-card, .prompt-card,
  .student-info, .toc-entry-content {
    background: white !important;
    border: 1px solid #ccc !important;
    backdrop-filter: none !important;
    color: black !important;
    box-shadow: none !important;
    page-break-inside: avoid;
  }

  h1, h2, h3, h4 {
    -webkit-text-fill-color: black !important;
    background: none !important;
    color: black !important;
  }

  p, li, span { color: black !important; }

  a { color: #0066cc !important; text-decoration: underline; }
}