/* DataLearn — общие стили (темная тема) */
:root {
  --accent: #6366f1;
  --accent-bright: #818cf8;
  --accent-dark: #4f46e5;
  --accent-soft: rgba(99, 102, 241, 0.14);
  --text: #f2f4f8;
  --muted: #a3adbf;
  --border: #232a36;
  --bg: #0a0c10;
  --bg-alt: #10131a;
  --card-bg: #141822;
  --radius: 14px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; color-scheme: dark; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

img, iframe { max-width: 100%; }

a { color: var(--accent-bright); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3 { color: var(--text); }

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Шапка */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 12, 16, 0.88);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 22px;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.5px;
}
.logo-img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: block;
}
.logo:hover { text-decoration: none; }
.logo span { color: var(--accent-bright); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--text);
  font-weight: 500;
  font-size: 15.5px;
}
.nav-links a:hover { color: var(--accent-bright); text-decoration: none; }
.nav-links a.active { color: var(--accent-bright); }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 26px;
  line-height: 1;
  cursor: pointer;
  color: var(--text);
  padding: 6px;
}

/* Кнопки */
.btn {
  display: inline-block;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 16px;
  border: 2px solid transparent;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.btn:hover { text-decoration: none; }

.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-dark); }

.btn-outline { border-color: var(--accent); color: var(--accent-bright); }
.btn-outline:hover { background: var(--accent-soft); }

.btn-small { padding: 9px 18px; font-size: 15px; }

/* Hero */
.hero {
  padding: 72px 0 64px;
  text-align: center;
  background:
    radial-gradient(700px 340px at 20% 0%, rgba(99, 102, 241, 0.18) 0%, transparent 70%),
    radial-gradient(700px 340px at 80% 10%, rgba(124, 58, 237, 0.16) 0%, transparent 70%);
}

.hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  line-height: 1.15;
  letter-spacing: -1px;
  margin: 0 0 18px;
}

.hero .subtitle {
  font-size: 20px;
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto 32px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-note {
  margin-top: 18px;
  font-size: 15px;
  color: var(--muted);
}

/* Секции */
.section { padding: 56px 0; }
.section-alt { background: var(--bg-alt); }

.section h2 {
  font-size: clamp(26px, 3.4vw, 34px);
  letter-spacing: -0.5px;
  margin: 0 0 10px;
}

.section .lead {
  color: var(--muted);
  max-width: 680px;
  margin: 0 0 34px;
  font-size: 18px;
}

/* Сетки и карточки */
.grid {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  align-items: start;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: flex-start;
}

.card h3 { margin: 0 0 8px; font-size: 20px; }
.card .tag {
  display: inline-block;
  align-self: flex-start;
  background: var(--accent-soft);
  color: var(--accent-bright);
  font-size: 13px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 12px;
  letter-spacing: 0.4px;
}
.card p { color: var(--muted); font-size: 16px; margin: 0 0 14px; }
.card p:last-child { margin-bottom: 0; }
.card .author { font-size: 14.5px; color: var(--text); font-weight: 600; margin-top: 4px; }
.card .card-actions { margin-top: 16px; display: flex; gap: 10px; flex-wrap: wrap; }

/* Шаги */
.step .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 18px;
  margin: 0 0 14px;
  flex: none;
}
.step h3 { margin-top: 0; }
.step p { margin-bottom: 0; }

/* Видео */
.video-wrap {
  position: relative;
  padding-top: 56.25%;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  background: #000;
}
.video-wrap iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.video-grid {
  display: grid;
  gap: 26px;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}
.video-item h3 { font-size: 17px; margin: 12px 0 0; line-height: 1.4; }

/* Подкасты */
.podcast-embed { margin-bottom: 22px; }
.podcast-embed iframe { border-radius: 12px; border: 0; }

/* Авторы */
.people { display: grid; gap: 22px; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); max-width: 760px; }
.person {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
}
.person .avatar {
  flex: none;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent-bright);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 19px;
}
.person .avatar-photo {
  flex: none;
  width: 88px;
  height: 88px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--border);
}
.person h3 { margin: 0 0 4px; font-size: 18px; }
.person p { margin: 0 0 10px; color: var(--muted); font-size: 15px; }
.person .person-links { margin: 10px 0 0; }

.people-wide { max-width: none; grid-template-columns: 1fr 1fr; }

.books summary {
  cursor: pointer;
  color: var(--accent-bright);
  font-weight: 600;
  font-size: 15px;
}
.books ul {
  margin: 10px 0 0;
  padding-left: 20px;
  color: var(--muted);
  font-size: 14.5px;
}
.books li { margin-bottom: 4px; }

/* CTA-блок */
.cta-banner {
  background: linear-gradient(120deg, var(--accent-dark), #7c3aed);
  border-radius: var(--radius);
  color: #fff;
  padding: 44px 36px;
  text-align: center;
}
.cta-banner h2 { margin: 0 0 10px; color: #fff; }
.cta-banner p { color: rgba(255, 255, 255, 0.85); margin: 0 0 24px; }
.cta-banner .btn { background: #fff; color: var(--accent-dark); }
.cta-banner .btn:hover { background: #e0e7ff; }

/* Подвал */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 36px 0;
  color: var(--muted);
  font-size: 15px;
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  align-items: center;
}
.footer-links { display: flex; gap: 20px; flex-wrap: wrap; }

/* Мобильная версия */
@media (max-width: 760px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    align-items: flex-start;
    padding: 16px 20px 20px;
    gap: 16px;
    box-shadow: var(--shadow);
  }
  .nav-links.open { display: flex; }
  .hero { padding: 48px 0 44px; }
  .section { padding: 40px 0; }
  .people-wide { grid-template-columns: 1fr; }
}