:root {
  --bg: #f6f6f4;
  --surface: #ffffff;
  --text: #121826;
  --muted: #7b8794;
  --accent: #2f4fef;
  --accent-soft: rgba(47, 79, 239, 0.1);
  --border: #e4e7eb;
  --shadow-soft: 0 14px 40px rgba(15, 23, 42, 0.08);
  --shadow-light: 0 10px 25px rgba(15, 23, 42, 0.06);
}

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

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.65;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(12px);
  background-color: rgba(246, 246, 244, 0.85);
  border-bottom: 1px solid rgba(228, 231, 235, 0.8);
}

.nav-shell {
  max-width: 1200px;
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  position: relative;
}

.brand {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  margin-right: auto;
}

.brand img {
  height: 40px;
  width: auto;
}

.nav-links {
  display: flex;
  gap: 32px;
  font-size: 0.94rem;
  font-weight: 500;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

.nav-links a {
  color: var(--muted);
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.nav-links a:hover,
.nav-links a:focus,
.nav-links a.active {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.hero {
  position: relative;
  overflow: hidden;
  background: radial-gradient(
      700px circle at 0% 0%,
      rgba(47, 79, 239, 0.14),
      transparent 60%
    ),
    radial-gradient(
      600px circle at 100% 30%,
      rgba(15, 23, 42, 0.08),
      transparent 60%
    ),
    var(--bg);
}

.hero-content {
  max-width: 1080px;
  margin: 0 auto;
  padding: 140px 20px 120px;
  display: grid;
  gap: 28px;
}

.hero-eyebrow {
  font-size: 0.82rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
}

.hero-title {
  font-size: clamp(2.6rem, 4vw, 3.6rem);
  font-weight: 600;
  line-height: 1.06;
  max-width: 26ch;
}

.hero-text {
  font-size: 1.08rem;
  max-width: 62ch;
  color: var(--muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 8px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease,
    background-color 0.2s ease, color 0.2s ease;
  cursor: pointer;
}

.btn-primary {
  background-color: var(--accent);
  color: #ffffff;
  box-shadow: 0 12px 25px rgba(47, 79, 239, 0.18);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 30px rgba(47, 79, 239, 0.22);
}

.btn-secondary {
  background-color: var(--accent-soft);
  color: var(--accent);
}

.btn-secondary:hover {
  transform: translateY(-2px);
}

.section {
  max-width: 1080px;
  margin: 0 auto 80px;
  padding: 0 20px;
}

.section h2 {
  font-size: 1.9rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.section p.lead {
  font-size: 1rem;
  color: var(--muted);
  max-width: 70ch;
}

.surface-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 28px;
  margin-top: 26px;
  box-shadow: var(--shadow-soft);
}

.surface-card h3 {
  font-size: 1.22rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.surface-card p {
  color: var(--muted);
}

.surface-card ul {
  list-style: none;
  margin-top: 20px;
  display: grid;
  gap: 10px;
}

.surface-card li {
  position: relative;
  padding-left: 22px;
  color: var(--text);
}

.surface-card li::before {
  content: "•";
  position: absolute;
  left: 6px;
  color: var(--accent);
}

.split {
  display: grid;
  gap: 26px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  margin-top: 26px;
}

.cta-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 28px;
  display: grid;
  gap: 18px;
  box-shadow: var(--shadow-light);
}

.download-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.support-links {
  margin-top: 24px;
  display: grid;
  gap: 12px;
  max-width: 360px;
}

.support-links a {
  display: inline-flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background-color: var(--surface);
  font-weight: 500;
  transition: transform 0.18s ease, border-color 0.18s ease;
}

.support-links a span {
  margin-left: 18px;
}

.support-links a:hover {
  transform: translateY(-3px);
  border-color: rgba(47, 79, 239, 0.35);
}

.chapter-grid {
  margin-top: 34px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 18px;
}

.chapter-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: transform 0.18s ease, box-shadow 0.18s ease,
    border-color 0.18s ease;
}

.chapter-card span {
  font-size: 0.82rem;
  color: var(--muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.chapter-card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.4;
}

.chapter-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 18px 35px rgba(15, 23, 42, 0.08);
  border-color: rgba(47, 79, 239, 0.4);
}

footer {
  max-width: 1080px;
  margin: 0 auto;
  padding: 40px 20px 60px;
  border-top: 1px solid rgba(228, 231, 235, 0.8);
  color: var(--muted);
  font-size: 0.9rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.article {
  max-width: 760px;
  margin: 0 auto;
  padding: 80px 20px 120px;
}

.article h1 {
  font-size: clamp(2.2rem, 4vw, 3rem);
  font-weight: 600;
  margin-bottom: 24px;
}

.article h2 {
  font-size: 1.4rem;
  font-weight: 600;
  margin-top: 40px;
  margin-bottom: 14px;
}

.article p {
  margin-bottom: 20px;
  color: var(--muted);
}

.article ul {
  margin: 20px 0 24px;
  padding-left: 22px;
  color: var(--muted);
}

.article li {
  margin-bottom: 10px;
}

/* Markdown Content Styles */
.markdown-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 60px 20px 120px;
  font-size: 1.05rem;
  line-height: 1.75;
}

.markdown-content h1 {
  font-size: clamp(2.2rem, 4vw, 3.2rem);
  font-weight: 700;
  margin-bottom: 32px;
  line-height: 1.15;
}

.markdown-content h2 {
  font-size: 1.75rem;
  font-weight: 600;
  margin-top: 56px;
  margin-bottom: 20px;
  line-height: 1.3;
}

.markdown-content h3 {
  font-size: 1.35rem;
  font-weight: 600;
  margin-top: 40px;
  margin-bottom: 16px;
}

.markdown-content p {
  margin-bottom: 24px;
  color: var(--text);
}

.markdown-content strong {
  font-weight: 600;
  color: var(--text);
}

.markdown-content em {
  font-style: italic;
  color: var(--muted);
}

.markdown-content ul,
.markdown-content ol {
  margin: 24px 0;
  padding-left: 28px;
}

.markdown-content li {
  margin-bottom: 12px;
  color: var(--text);
}

.markdown-content blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 24px;
  margin: 32px 0;
  color: var(--muted);
  font-style: italic;
}

.markdown-content code {
  background-color: var(--accent-soft);
  padding: 3px 8px;
  border-radius: 6px;
  font-family: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
  font-size: 0.9em;
}

.markdown-content pre {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin: 28px 0;
  overflow-x: auto;
}

.markdown-content pre code {
  background-color: transparent;
  padding: 0;
  border-radius: 0;
}

.chapter-header {
  text-align: center;
  padding: 80px 20px 40px;
  background: radial-gradient(
      600px circle at 50% 0%,
      rgba(47, 79, 239, 0.1),
      transparent 60%
    ),
    var(--bg);
}

.chapter-nav {
  max-width: 800px;
  margin: 40px auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
}

.chapter-nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  font-weight: 500;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.chapter-nav-btn:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

@media (max-width: 720px) {
  .hero-content {
    padding-top: 110px;
  }

  .nav-shell {
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
    position: relative;
  }

  .nav-links {
    position: static;
    transform: none;
    order: 2;
    flex-basis: 100%;
    justify-content: center;
  }

  .brand {
    flex-basis: 100%;
    text-align: center;
  }
}