/* ============================================================
   PHYSICS OF SPACE — Global Styles (rng-t.ru inspired)
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;600;700;900&family=Space+Mono:wght@400;700&display=swap');

/* ---------- CSS Variables ---------- */
:root {
  --bg-primary:    #02030a;
  --bg-secondary:  #070b1a;
  --bg-card:       #0d1530;
  --bg-card-hover: #111d40;
  --accent-blue:   #4f8ef7;
  --accent-purple: #9b59ff;
  --accent-neon:   #00e5ff;
  --accent-pink:   #ff4fb3;
  --text-primary:  #e8eaf6;
  --text-secondary:#9fa8da;
  --text-muted:    #546e96;
  --border:        rgba(79, 142, 247, 0.2);
  --glow-blue:     0 0 24px rgba(79,142,247,0.35);
  --glow-neon:     0 0 20px rgba(0,229,255,0.4);
  --font-body:     'Outfit', sans-serif;
  --font-mono:     'Space Mono', monospace;
  --radius:        14px;
  --radius-sm:     8px;
  --transition:    0.3s cubic-bezier(0.4,0,0.2,1);
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  background-image:
    radial-gradient(ellipse at 20% 20%, rgba(79,142,247,0.06) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 80%, rgba(155,89,255,0.06) 0%, transparent 60%);
}

/* ---- Stars background ---- */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    radial-gradient(1px 1px at 10% 15%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(1px 1px at 30% 40%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 55% 20%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 70% 65%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1px 1px at 90% 10%, rgba(255,255,255,0.7) 0%, transparent 100%),
    radial-gradient(1px 1px at 15% 80%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 45% 90%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(2px 2px at 60% 50%, rgba(255,255,255,0.3) 0%, transparent 100%),
    radial-gradient(1px 1px at 85% 35%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 25% 55%, rgba(255,255,255,0.5) 0%, transparent 100%);
  pointer-events: none;
  z-index: 0;
}

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

img { max-width: 100%; display: block; }

/* ============================================================
   HEADER / NAVIGATION
   ============================================================ */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(7, 11, 26, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}

.nav-container {
  max-width: 1300px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 700;
  background: linear-gradient(90deg, var(--accent-neon), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 1px;
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 6px;
  list-style: none;
}

.nav-links li a {
  display: block;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all var(--transition);
  letter-spacing: 0.3px;
}

.nav-links li a:hover,
.nav-links li a.active {
  color: var(--accent-neon);
  background: rgba(0, 229, 255, 0.08);
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 26px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition);
}

/* ============================================================
   MAIN CONTENT WRAPPER
   ============================================================ */
main {
  position: relative;
  z-index: 1;
  max-width: 1300px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}

/* ============================================================
   HERO SECTION
   ============================================================ */
.hero {
  text-align: center;
  padding: 100px 24px 80px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(79,142,247,0.12) 0%, transparent 70%);
  pointer-events: none;
}

.hero-badge {
  display: inline-block;
  background: rgba(0,229,255,0.1);
  border: 1px solid rgba(0,229,255,0.3);
  color: var(--accent-neon);
  padding: 6px 18px;
  border-radius: 99px;
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 24px;
  background: linear-gradient(135deg, #fff 0%, var(--accent-blue) 50%, var(--accent-purple) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 40px;
}

/* ============================================================
   PAGE BANNER (inner pages)
   ============================================================ */
.page-banner {
  text-align: center;
  margin-bottom: 48px;
}

.page-banner h1 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 900;
  background: linear-gradient(135deg, #fff, var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 12px;
}

.page-banner p {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

/* ============================================================
   SECTION HEADINGS
   ============================================================ */
.section-title {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  margin-bottom: 12px;
  background: linear-gradient(90deg, var(--text-primary), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: 40px;
}

.section-divider {
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-neon), var(--accent-blue));
  border-radius: 2px;
  margin-bottom: 16px;
}

/* ============================================================
   BADGES
   ============================================================ */
.badge {
  display: inline-block;
  padding: 3px 12px;
  border-radius: 99px;
  font-size: 0.78rem;
  font-weight: 700;
  font-family: var(--font-mono);
}

.badge-blue   { background: rgba(79,142,247,0.15); color: var(--accent-blue); }
.badge-purple { background: rgba(155,89,255,0.15); color: var(--accent-purple); }
.badge-neon   { background: rgba(0,229,255,0.12);  color: var(--accent-neon); }
.mb-8 { margin-bottom: 8px; }

/* ============================================================
   CARDS
   ============================================================ */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(79,142,247,0.4);
  box-shadow: var(--glow-blue);
  transform: translateY(-4px);
}

.card:hover::before { opacity: 1; }

.card-icon {
  font-size: 2.4rem;
  margin-bottom: 16px;
}

.card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ============================================================
   FORMULA CARDS
   ============================================================ */
.formula-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  margin-bottom: 24px;
  transition: all var(--transition);
}

.formula-card:hover {
  border-color: rgba(155,89,255,0.5);
  box-shadow: 0 0 24px rgba(155,89,255,0.2);
  transform: translateY(-2px);
}

.formula-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--accent-neon);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.formula-display {
  background: rgba(0,0,0,0.4);
  border: 1px solid rgba(155,89,255,0.3);
  border-radius: var(--radius-sm);
  padding: 20px;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 1.3rem;
  color: #fff;
  margin: 16px 0;
  letter-spacing: 1px;
}

.formula-vars {
  list-style: none;
  margin-top: 16px;
}

.formula-vars li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 6px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.formula-vars li:last-child { border-bottom: none; }

.var-badge {
  font-family: var(--font-mono);
  background: rgba(79,142,247,0.15);
  color: var(--accent-blue);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.85rem;
  white-space: nowrap;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 99px;
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  font-family: var(--font-body);
  letter-spacing: 0.3px;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  color: #fff;
  box-shadow: 0 4px 20px rgba(79,142,247,0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(79,142,247,0.5);
  color: #fff;
}

.btn-outline {
  background: transparent;
  border: 1.5px solid var(--accent-neon);
  color: var(--accent-neon);
}

.btn-outline:hover {
  background: rgba(0,229,255,0.1);
  box-shadow: var(--glow-neon);
  color: var(--accent-neon);
}

.btn-lg { padding: 16px 40px; font-size: 1.05rem; }

/* ============================================================
   COMMENTS SECTION
   ============================================================ */
.comment {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 20px;
  transition: all var(--transition);
}

.comment:hover {
  border-color: rgba(79,142,247,0.3);
}

.comment-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 12px;
}

.comment-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.comment-author { font-weight: 700; font-size: 0.98rem; }
.comment-date { color: var(--text-muted); font-size: 0.82rem; }
.comment-body { color: var(--text-secondary); font-size: 0.95rem; line-height: 1.65; }

/* ============================================================
   GALLERY
   ============================================================ */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.gallery-item {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  aspect-ratio: 4/3;
  cursor: pointer;
  background: var(--bg-card);
  border: 1px solid var(--border);
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.gallery-item:hover img { transform: scale(1.08); }

.gallery-caption {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(2,3,10,0.9) 0%, transparent 60%);
  display: flex;
  align-items: flex-end;
  padding: 20px;
  opacity: 0;
  transition: opacity var(--transition);
}

.gallery-item:hover .gallery-caption { opacity: 1; }

.gallery-caption p {
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  line-height: 1.4;
}

/* ============================================================
   TABLE
   ============================================================ */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  margin-bottom: 40px;
}

.data-table thead tr {
  background: linear-gradient(90deg, rgba(79,142,247,0.2), rgba(155,89,255,0.2));
}

.data-table th {
  padding: 16px 20px;
  text-align: left;
  font-weight: 700;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border);
  font-size: 0.88rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.data-table td {
  padding: 14px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  color: var(--text-secondary);
}

.data-table tbody tr:hover {
  background: rgba(79,142,247,0.06);
}

.data-table tbody tr td:first-child {
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.score-good { color: #4caf82; font-weight: 700; }

/* ============================================================
   IFRAME / VIDEO GRID
   ============================================================ */
.media-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
  margin-bottom: 48px;
}

.media-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}

.media-item:hover {
  border-color: rgba(79,142,247,0.4);
  box-shadow: var(--glow-blue);
  transform: translateY(-3px);
}

.media-item iframe {
  width: 100%;
  aspect-ratio: 16/9;
  border: none;
  display: block;
}

.media-label {
  padding: 14px 18px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.media-item.featured {
  border-color: var(--accent-purple);
  position: relative;
}

.media-item.featured::after {
  content: '⭐ Авторский ресурс';
  position: absolute;
  top: 12px;
  right: 12px;
  background: linear-gradient(135deg, var(--accent-purple), var(--accent-pink));
  color: #fff;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 99px;
}

/* ============================================================
   CHARTS
   ============================================================ */
.charts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: 32px;
  margin-top: 40px;
}

.chart-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.chart-card h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ============================================================
   TEST / QUIZ
   ============================================================ */
.quiz-wrapper { max-width: 820px; margin: 0 auto; }

.quiz-question {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  margin-bottom: 24px;
  transition: border-color var(--transition);
}

.quiz-question:hover { border-color: rgba(79,142,247,0.35); }

.question-number {
  display: inline-block;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 3px 12px;
  border-radius: 99px;
  margin-bottom: 12px;
  font-family: var(--font-mono);
}

.quiz-question h4 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 18px;
  line-height: 1.5;
}

.quiz-options { display: flex; flex-direction: column; gap: 10px; }

.quiz-option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255,255,255,0.08);
  cursor: pointer;
  transition: all var(--transition);
  font-size: 0.95rem;
}

.quiz-option:hover { background: rgba(79,142,247,0.08); border-color: rgba(79,142,247,0.3); }
.quiz-option input { accent-color: var(--accent-blue); }

.quiz-option.correct { background: rgba(76,175,130,0.12); border-color: #4caf82; }
.quiz-option.wrong   { background: rgba(244,67,54,0.12);  border-color: #f44336; }

.text-input {
  width: 100%;
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  outline: none;
  transition: border-color var(--transition);
}

.text-input:focus { border-color: var(--accent-blue); }
.text-input.correct { border-color: #4caf82; background: rgba(76,175,130,0.08); }
.text-input.wrong   { border-color: #f44336; background: rgba(244,67,54,0.08); }

/* Result panel */
.result-panel {
  display: none;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px;
  text-align: center;
  margin-top: 32px;
}

.result-panel.show { display: block; }

.result-score {
  font-size: 5rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--accent-neon), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 12px;
}

.result-label {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.result-message { color: var(--text-secondary); }

/* ============================================================
   INFO BOXES
   ============================================================ */
.info-box {
  background: rgba(79,142,247,0.08);
  border: 1px solid rgba(79,142,247,0.25);
  border-radius: var(--radius);
  padding: 24px 28px;
  margin-bottom: 32px;
}

.info-box h3 {
  color: var(--accent-blue);
  font-size: 1.1rem;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.info-box p, .info-box li { color: var(--text-secondary); font-size: 0.95rem; }
.info-box ol, .info-box ul { padding-left: 20px; }
.info-box li { margin-bottom: 6px; }

/* ============================================================
   GLOSSARY
   ============================================================ */
.glossary-list { list-style: none; }

.glossary-list li {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 14px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
}

.glossary-list li:last-child { border-bottom: none; }

.glossary-term {
  font-family: var(--font-mono);
  background: rgba(155,89,255,0.15);
  color: var(--accent-purple);
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  white-space: nowrap;
  min-width: 200px;
}

/* ============================================================
   FOOTER
   ============================================================ */
footer {
  position: relative;
  z-index: 1;
  background: rgba(7,11,26,0.9);
  border-top: 1px solid var(--border);
  padding: 48px 24px 32px;
  text-align: center;
}

.footer-logo {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 700;
  background: linear-gradient(90deg, var(--accent-neon), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 12px;
}

.footer-subtitle {
  color: var(--text-muted);
  font-size: 0.88rem;
  margin-bottom: 24px;
}

.footer-nav {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 24px;
  flex-wrap: wrap;
  margin-bottom: 28px;
}

.footer-nav a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition);
}

.footer-nav a:hover { color: var(--accent-neon); }

.footer-copy {
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* ============================================================
   SCROLL ANIMATIONS
   ============================================================ */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: rgba(7,11,26,0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 16px 24px 24px;
    border-bottom: 1px solid var(--border);
  }
  .nav-links.open { display: flex; }
  .hero { padding: 60px 16px 48px; }
  .cards-grid { grid-template-columns: 1fr; }
  .media-grid { grid-template-columns: 1fr; }
  .charts-grid { grid-template-columns: 1fr; }
  .gallery-grid { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
  .glossary-list li { flex-direction: column; gap: 8px; }
  .glossary-term { min-width: auto; }
}