/* Стили для статических hub-страниц /learn/<topic>.
 * Единый файл: загружается один раз и кешируется крауллером браузером
 * между переходами по всем семи хабам. Per-hub акцент задаётся inline-стилем
 * в head конкретной страницы (--hub-accent override). */

:root {
  --hub-bg: #f7f8fb;
  --hub-card-bg: #ffffff;
  --hub-text: #0a0a1f;
  --hub-text-soft: #475569;
  --hub-border: #e2e8f0;
  --hub-brand: #2563eb;
  --hub-brand-soft: #dbeafe;
  --hub-accent: #2563eb;
  --hub-radius-md: 14px;
  --hub-radius-lg: 22px;
  --hub-shadow-soft: 0 4px 20px -10px rgba(15, 23, 42, 0.18);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--hub-bg);
  color: var(--hub-text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue',
    Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  line-height: 1.55;
}

a { color: var(--hub-brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.hub-container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.hub-topbar {
  border-bottom: 1px solid var(--hub-border);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(140%) blur(8px);
  position: sticky;
  top: 0;
  z-index: 30;
}
.hub-topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  padding-bottom: 14px;
}
.hub-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--hub-text);
  font-weight: 700;
  text-decoration: none;
}
.hub-brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--hub-brand);
  color: #fff;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.5px;
}
.hub-brand-name {
  font-size: 15px;
  letter-spacing: 0.2px;
}
.hub-topnav {
  display: flex;
  gap: 22px;
  font-size: 14px;
  font-weight: 600;
}
.hub-topnav a { color: var(--hub-text-soft); }
.hub-topnav a:hover { color: var(--hub-brand); text-decoration: none; }

.hub-main { display: block; }

.hub-hero {
  padding: 64px 0 56px;
  background: linear-gradient(180deg, #f7f8fb 0%, #eef2ff 100%);
}
.hub-hero-eyebrow {
  display: inline-block;
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--hub-brand-soft);
  color: var(--hub-brand);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  margin-bottom: 18px;
}
.hub-hero-title {
  font-size: clamp(28px, 4.4vw, 44px);
  line-height: 1.15;
  font-weight: 800;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
  max-width: 880px;
}
.hub-hero-lead {
  font-size: clamp(16px, 1.7vw, 18px);
  color: var(--hub-text-soft);
  max-width: 760px;
  margin: 0 0 28px;
}
.hub-hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.hub-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 15px;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  border: 1px solid transparent;
  text-decoration: none;
  cursor: pointer;
}
.hub-btn-primary {
  background: var(--hub-brand);
  color: #fff;
  box-shadow: 0 8px 22px -10px rgba(37, 99, 235, 0.7);
}
.hub-btn-primary:hover {
  background: #1d4ed8;
  text-decoration: none;
  transform: translateY(-1px);
}
.hub-btn-ghost {
  background: transparent;
  color: var(--hub-text);
  border-color: var(--hub-border);
}
.hub-btn-ghost:hover { background: #fff; text-decoration: none; }
.hub-btn-large { padding: 14px 28px; font-size: 16px; }

.hub-section-title {
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 800;
  letter-spacing: -0.01em;
  margin: 0 0 28px;
}

.hub-why { padding: 64px 0; }
.hub-why-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}
.hub-why-card {
  background: var(--hub-card-bg);
  border-radius: var(--hub-radius-lg);
  border: 1px solid var(--hub-border);
  padding: 28px;
  box-shadow: var(--hub-shadow-soft);
}
.hub-why-num {
  width: 36px; height: 36px;
  border-radius: 10px;
  background: var(--hub-accent);
  color: #0a0a1f;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 14px;
  margin-bottom: 14px;
}
.hub-why-title {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 8px;
}
.hub-why-body {
  color: var(--hub-text-soft);
  margin: 0;
  font-size: 15px;
}

.hub-course-callout { padding: 36px 0 24px; }
.hub-course-card {
  border-radius: var(--hub-radius-lg);
  padding: 36px;
  background: linear-gradient(135deg, #0a0a1f 0%, #1e1b4b 100%);
  color: #fff;
  box-shadow: 0 30px 60px -30px rgba(15, 23, 42, 0.4);
}
.hub-course-card-meta {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: var(--hub-accent);
  margin-bottom: 12px;
}
.hub-course-card-title {
  font-size: clamp(22px, 2.6vw, 28px);
  font-weight: 800;
  margin: 0 0 12px;
  color: #fff;
}
.hub-course-card-lead {
  color: rgba(255, 255, 255, 0.78);
  font-size: 16px;
  margin: 0 0 24px;
  max-width: 640px;
}
.hub-course-card .hub-btn-primary {
  background: var(--hub-accent);
  color: #0a0a1f;
  box-shadow: none;
}
.hub-course-card .hub-btn-primary:hover { background: #fff; }

.hub-learn { padding: 64px 0; }
.hub-learn-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}
.hub-learn-card {
  background: var(--hub-card-bg);
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-md);
  padding: 22px;
}
.hub-learn-card-title {
  font-size: 16px;
  font-weight: 700;
  margin: 0 0 8px;
}
.hub-learn-card-body {
  color: var(--hub-text-soft);
  margin: 0;
  font-size: 14.5px;
}

.hub-roadmap { padding: 24px 0 64px; }
.hub-roadmap-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}
.hub-roadmap-item {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 20px;
  background: var(--hub-card-bg);
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-md);
  padding: 20px 24px;
  align-items: start;
}
.hub-roadmap-num {
  width: 44px; height: 44px;
  border-radius: 12px;
  background: var(--hub-brand-soft);
  color: var(--hub-brand);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 14px;
}
.hub-roadmap-title {
  font-size: 16px;
  font-weight: 700;
  margin: 0 0 4px;
}
.hub-roadmap-text {
  margin: 0;
  color: var(--hub-text-soft);
  font-size: 14.5px;
}

.hub-related { padding: 24px 0 64px; }
.hub-related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 18px;
}
.hub-related-card {
  display: flex;
  flex-direction: column;
  background: var(--hub-card-bg);
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-md);
  padding: 22px;
  color: var(--hub-text);
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.hub-related-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--hub-shadow-soft);
  text-decoration: none;
}
.hub-related-meta {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--hub-text-soft);
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}
.hub-related-title {
  font-size: 17px;
  font-weight: 700;
  margin: 0 0 8px;
}
.hub-related-lead {
  margin: 0 0 16px;
  color: var(--hub-text-soft);
  font-size: 14px;
}
.hub-related-cta {
  color: var(--hub-brand);
  font-weight: 700;
  font-size: 14px;
  margin-top: auto;
}

.hub-faq { padding: 24px 0 64px; }
.hub-faq-list {
  display: grid;
  gap: 10px;
}
.hub-faq-item {
  background: var(--hub-card-bg);
  border: 1px solid var(--hub-border);
  border-radius: var(--hub-radius-md);
  padding: 18px 22px;
}
.hub-faq-item[open] { box-shadow: var(--hub-shadow-soft); }
.hub-faq-question {
  font-weight: 700;
  cursor: pointer;
  font-size: 16px;
  list-style: none;
  position: relative;
  padding-right: 28px;
}
.hub-faq-question::-webkit-details-marker { display: none; }
.hub-faq-question::after {
  content: '+';
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  color: var(--hub-text-soft);
  font-size: 18px;
  font-weight: 700;
}
.hub-faq-item[open] .hub-faq-question::after { content: '−'; }
.hub-faq-answer {
  margin-top: 12px;
  color: var(--hub-text-soft);
  font-size: 15px;
  line-height: 1.6;
}

.hub-cta {
  padding: 64px 0 80px;
  background: linear-gradient(180deg, #eef2ff 0%, #f7f8fb 100%);
  text-align: center;
}
.hub-cta-title {
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 800;
  margin: 0 0 12px;
}
.hub-cta-lead {
  color: var(--hub-text-soft);
  font-size: 16px;
  max-width: 600px;
  margin: 0 auto 28px;
}

.hub-footer {
  border-top: 1px solid var(--hub-border);
  background: #ffffff;
  padding: 28px 0;
}
.hub-footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.hub-footer-brand {
  color: var(--hub-text-soft);
  font-size: 14px;
}
.hub-footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 14px;
}
.hub-footer-nav a { color: var(--hub-text-soft); font-weight: 600; }

@media (max-width: 768px) {
  .hub-topnav { display: none; }
  .hub-hero { padding: 40px 0 32px; }
  .hub-why { padding: 40px 0; }
  .hub-why-grid { grid-template-columns: 1fr; }
  .hub-learn { padding: 40px 0; }
  .hub-learn-grid { grid-template-columns: 1fr; }
  .hub-roadmap-item {
    grid-template-columns: 40px 1fr;
    gap: 14px;
    padding: 16px 18px;
  }
  .hub-roadmap-num { width: 36px; height: 36px; }
  .hub-cta { padding: 48px 0 56px; }
  .hub-course-card { padding: 28px; }
}