:root {
  color: #1f2937;
  background: #f9fafb;
  --font-base: 1rem;
  --font-sm: 0.9rem;
  --font-lg: 1.15rem;
  --font-xl: 1.4rem;
  --font-xxl: 2.4rem;
  --line-height-body: 1.7;
  --line-height-heading: 1.25;
  --space-xs: 8px;
  --space-sm: 12px;
  --space-md: 20px;
  --space-lg: 32px;
  --space-xl: 48px;
  --border-subtle: #e5e7eb;
  --text-muted: #6b7280;
}

* {
  box-sizing: border-box;
}

body {
  font-family: "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  margin: 0;
  color: #1f2937;
  background: #f9fafb;
  line-height: var(--line-height-body);
  font-size: var(--font-base);
}

.page {
  max-width: 960px;
  margin: 64px auto;
  padding: 0 24px;
}

.page--narrow {
  max-width: 760px;
}

.site-header {
  margin-bottom: var(--space-xl);
}

.site-nav {
  width: 100%;
  max-width: 760px;
  margin: 0 auto var(--space-lg);
  padding: 14px 18px;
  background: #ffffff;
  border: 1px solid var(--border-subtle);
  border-radius: 16px;
  box-shadow: 0 8px 18px rgba(15, 23, 42, 0.06);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.site-nav__logo {
  font-size: var(--font-lg);
  font-weight: 600;
  border-bottom: none;
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: var(--font-sm);
}

.site-nav__link {
  color: #374151;
  border-bottom: 2px solid transparent;
  padding-bottom: 2px;
}

.site-nav__link:hover {
  color: #111827;
  border-color: #9ca3af;
}

.site-nav__link.is-active {
  color: #111827;
  border-color: #111827;
}

.site-nav__cta {
  font-size: var(--font-sm);
  padding: 8px 14px;
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  background: #f8fafc;
  font-weight: 600;
  white-space: nowrap;
}

.site-nav__cta:hover {
  background: #eef2f7;
  border-color: #94a3b8;
  color: #111827;
}

.site-nav a {
  text-decoration: none;
  border-bottom: none;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.site-nav a:hover {
  border-bottom: none;
}

.site-nav a:focus-visible {
  outline: 2px solid #1f2937;
  outline-offset: 3px;
  border-radius: 6px;
}

h1 {
  font-size: var(--font-xxl);
  margin: 0 0 var(--space-sm);
  letter-spacing: -0.4px;
  line-height: var(--line-height-heading);
}

h2 {
  font-size: var(--font-xl);
  margin: var(--space-lg) 0 var(--space-sm);
  letter-spacing: -0.2px;
  line-height: var(--line-height-heading);
}

h3 {
  font-size: var(--font-lg);
  margin: var(--space-md) 0 var(--space-xs);
  letter-spacing: -0.1px;
  line-height: var(--line-height-heading);
}

h4 {
  font-size: var(--font-base);
  margin: var(--space-md) 0 var(--space-xs);
  letter-spacing: -0.05px;
  line-height: var(--line-height-heading);
}

p {
  margin: 0 0 var(--space-md);
  font-size: var(--font-base);
}

ul {
  padding-left: 20px;
  margin: 0 0 var(--space-md);
}

a {
  color: #1f2937;
  text-decoration: none;
  border-bottom: 1px solid #d1d5db;
  transition: border-color 0.2s ease, color 0.2s ease;
}

a:hover {
  border-color: #1f2937;
}

.lead {
  font-size: var(--font-lg);
  margin-bottom: var(--space-md);
  max-width: 56ch;
}

.stack {
  margin: 0;
  padding: 0;
  list-style: none;
}

.stack li + li {
  margin-top: var(--space-sm);
}

.stack--cards li {
  background: #ffffff;
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: var(--space-md);
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
}

.stack--cards li + li {
  margin-top: var(--space-md);
}

.cta {
  display: inline-block;
  margin-top: var(--space-sm);
  padding: 12px 18px;
  border: 1px solid #1f2937;
  border-radius: 6px;
  color: #1f2937;
  text-decoration: none;
  font-weight: 600;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.cta:hover {
  background: #1f2937;
  color: #f9fafb;
}

.meta {
  font-size: var(--font-sm);
  color: var(--text-muted);
  margin: 0;
}

.closing {
  margin-top: var(--space-lg);
  color: #4b5563;
  font-style: italic;
}

.section-spacer {
  margin-top: var(--space-md);
}

.page-content {
  max-width: 760px;
  margin: 0 auto;
}

.page-content section + section {
  margin-top: var(--space-xl);
}

.content-card {
  background: #ffffff;
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  padding: var(--space-md);
  margin: var(--space-md) 0;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
}

.content-card h3 {
  margin-top: 0;
}

@media (max-width: 720px) {
  .page {
    margin: 48px auto;
    padding: 0 20px;
  }

  h1 {
    font-size: 2rem;
  }

  .site-header {
    margin-bottom: var(--space-lg);
  }

  .site-nav {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-sm);
  }

  .site-nav__logo {
    text-align: center;
  }

  .site-nav__links {
    justify-content: center;
    flex-wrap: wrap;
  }

  .site-nav__cta {
    align-self: center;
  }

  .page-content section + section {
    margin-top: var(--space-lg);
  }
}