:root {
  --ink: #e8eef8;
  --muted: #9aa9bd;
  --line: rgba(148, 163, 184, 0.16);
  --panel: rgba(12, 23, 39, 0.88);
  --accent: #79d8ff;
  --sidebar: 19rem;
  color-scheme: dark;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-height: 100vh; color: var(--ink); background: radial-gradient(circle at 75% 0%, rgba(70, 96, 180, 0.2), transparent 35rem), #07101d; }
a { color: var(--accent); }
.sidebar { position: fixed; inset: 0 auto 0 0; z-index: 20; display: flex; width: var(--sidebar); flex-direction: column; padding: 2rem 1.5rem; overflow-y: auto; background: rgba(5, 12, 24, 0.94); border-right: 1px solid var(--line); backdrop-filter: blur(18px); }
.brand { display: flex; align-items: center; gap: .75rem; color: #fff; font-size: 1.08rem; font-weight: 750; letter-spacing: .01em; text-decoration: none; }
.brand-mark { color: var(--accent); font-size: 1.55rem; text-shadow: 0 0 18px var(--accent); }
.nav { margin-top: 2.5rem; }
.nav a { display: block; color: var(--muted); text-decoration: none; transition: color .18s ease, background .18s ease; }
.nav a:hover, .nav a.active { color: #fff; }
.nav-home, .nav-heading { padding: .55rem .7rem; border-radius: .5rem; font-weight: 700; }
.nav a.active { background: rgba(121, 216, 255, .09); }
.nav-section { margin-top: 1.1rem; }
.nav ul { margin: .45rem 0 0; padding: 0; list-style: none; }
.nav li a { padding: .42rem .7rem .42rem 1.25rem; border-radius: .45rem; font-size: .9rem; line-height: 1.35; }
.sidebar-footer { margin: auto 0 0; padding-top: 2rem; color: #66758a; font-size: .8rem; }
.main { margin-left: var(--sidebar); min-height: 100vh; }
.page-shell { width: min(100% - 3rem, 62rem); margin: 0 auto; padding: 5.5rem 0 7rem; }
.hero, .page-header { max-width: 50rem; margin-bottom: 2.8rem; }
.eyebrow { margin: 0 0 .8rem; color: var(--accent); font-size: .78rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
h1 { margin: 0; color: #fff; font-size: clamp(2.3rem, 5vw, 4.7rem); line-height: 1.02; letter-spacing: -.045em; }
.page-header h1 { font-size: clamp(2.2rem, 4vw, 3.6rem); }
.lead { margin: 1.25rem 0 0; color: #b8c6d9; font-size: clamp(1.05rem, 2vw, 1.3rem); line-height: 1.65; }
.breadcrumb { display: inline-block; margin-bottom: 1.35rem; color: var(--muted); text-decoration: none; }
.prose { color: #cbd5e1; font-size: 1.02rem; line-height: 1.8; }
.prose h2, .prose h3, .prose h4 { color: #f5f8ff; line-height: 1.25; }
.prose h2 { margin-top: 2.8rem; font-size: 1.65rem; }
.prose h3 { margin-top: 2rem; }
.prose img { max-width: 100%; height: auto; border: 1px solid var(--line); border-radius: .8rem; }
.prose code { padding: .15em .35em; color: #d9e8ff; background: rgba(148, 163, 184, .12); border-radius: .3rem; }
.prose pre { margin: 1.4rem 0; padding: 1.2rem; overflow-x: auto; border: 1px solid var(--line); border-radius: .7rem; background: #050b14; }
.prose pre code { padding: 0; background: transparent; }
.home-copy { max-width: 48rem; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr)); gap: 1rem; margin-top: 3rem; }
.card { display: flex; min-height: 13rem; flex-direction: column; padding: 1.35rem; color: var(--muted); text-decoration: none; border: 1px solid var(--line); border-radius: .85rem; background: linear-gradient(145deg, rgba(20, 35, 58, .78), rgba(10, 20, 35, .72)); transition: transform .18s ease, border-color .18s ease; }
.card:hover { transform: translateY(-3px); border-color: rgba(121, 216, 255, .45); }
.card-kicker { margin-bottom: .65rem; color: var(--accent); font-size: .72rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.card strong { margin-bottom: .65rem; color: #fff; font-size: 1.35rem; }
.card-link { margin-top: auto; color: var(--accent); font-weight: 700; }
.article-list { display: grid; gap: .8rem; margin-top: 2.5rem; }
.article-item { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: 1.15rem 1.25rem; color: var(--muted); text-decoration: none; border: 1px solid var(--line); border-radius: .7rem; background: var(--panel); }
.article-item:hover { border-color: rgba(121, 216, 255, .4); }
.article-item h2 { margin: 0; color: #fff; font-size: 1.08rem; }
.article-item p { margin: .35rem 0 0; }
.article-item > span { color: var(--accent); font-size: 1.4rem; }
.button { display: inline-block; margin-top: 1rem; padding: .75rem 1rem; color: #06111f; background: var(--accent); border-radius: .55rem; font-weight: 800; text-decoration: none; }
.nav-toggle, .nav-button, .backdrop { display: none; }
@media (max-width: 800px) {
  .sidebar { width: min(20rem, 86vw); transform: translateX(-101%); transition: transform .22s ease; }
  .main { margin-left: 0; }
  .page-shell { width: min(100% - 2rem, 62rem); padding-top: 5rem; }
  .nav-button { position: fixed; top: 1rem; left: 1rem; z-index: 30; display: grid; gap: 4px; width: 2.7rem; height: 2.7rem; place-content: center; border: 1px solid var(--line); border-radius: .55rem; background: #0b1626; }
  .nav-button span { display: block; width: 1.15rem; height: 2px; background: #fff; }
  .nav-toggle:checked ~ .sidebar { transform: translateX(0); }
  .nav-toggle:checked ~ .backdrop { position: fixed; inset: 0; z-index: 10; display: block; background: rgba(0, 0, 0, .58); }
}