:root {
  --bg: #0b0f14;
  --bg-alt: #10151c;
  --text: #e8eef6;
  --muted: #b5c4d6;
  --brand: #0f4c81;
  --brand-2: #4ecdc4;
  --card: #131a23;
  --border: #223041;
  --shadow: 0 6px 30px rgba(0,0,0,.25);
}
:root.light {
  --bg: #f7fbff; --bg-alt: #ffffff; --text: #0e1621; --muted: #4b5b70;
  --brand: #0f4c81; --brand-2: #2f9e8b; --card: #ffffff; --border: #e1e8f0;
  --shadow: 0 6px 24px rgba(15,25,35,.1);
}
* { box-sizing: border-box }
html, body { margin:0; padding:0; }
body { font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Apple Color Emoji","Segoe UI Emoji", "Segoe UI Symbol", sans-serif; background: var(--bg); color: var(--text); line-height: 1.6; }
.container { width: min(1100px, 90vw); margin: 0 auto; padding: 2rem 0 4rem; }
.site-header, .site-footer { width: 100%; display: flex; align-items: center; justify-content: space-between; background: var(--bg-alt); border-bottom: 1px solid var(--border); padding: .8rem 5vw; position: sticky; top: 0; z-index: 10; }
.site-footer { position: static; border-top: 1px solid var(--border); border-bottom: none; padding: 2rem 5vw; display: block; text-align: center; }
.brand { display:flex; gap:.6rem; align-items:center; color:var(--text); text-decoration:none; font-weight:700; letter-spacing:.2px }
.brand img { filter: drop-shadow(0 2px 6px rgba(0,0,0,.25)); }
.nav a { color: var(--muted); text-decoration: none; margin: 0 .6rem; padding: .4rem .6rem; border-radius: .5rem; }
.nav a:hover, .nav a:focus { background: var(--card); color: var(--text); outline: none; }
.theme-toggle { background: var(--card); color: var(--text); border: 1px solid var(--border); padding: .45rem .6rem; border-radius: .5rem; cursor: pointer; }
h1, h2, h3 { line-height: 1.2; } h1 { font-size: clamp(1.8rem, 2.5vw + 1rem, 2.6rem); margin-top:0 } h2 { margin-top: 2rem; } p { margin: 0.75rem 0; color: var(--text); }
.hero { margin: 1rem 0 2rem; padding: 2rem; border:1px solid var(--border); background: linear-gradient(135deg, rgba(15,76,129,.12), rgba(78,205,196,.06)); border-radius: 1rem; box-shadow: var(--shadow) }
.hero p { color: var(--muted); max-width: 75ch; }
.btn { display: inline-block; padding: .7rem 1rem; border-radius: .6rem; border:1px solid var(--border); color: var(--text); text-decoration: none; background: var(--card); margin-right:.75rem; }
.btn.primary { background: linear-gradient(135deg, var(--brand), var(--brand-2)); border: none; }
.grid.three { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.card { background: var(--card); border:1px solid var(--border); border-radius: .9rem; padding:1rem; box-shadow: var(--shadow) }
.card h3 { margin: .2rem 0 .6rem; }
.checklist { list-style: none; padding-left: 0; }
.checklist li { padding-left: 1.6rem; position: relative; margin: .4rem 0; color: var(--muted); }
.checklist li::before { content: "✔"; position: absolute; left: 0; color: var(--brand-2); }
.diagram img { width: 100%; border:1px solid var(--border); border-radius: .8rem; background: var(--bg-alt); margin-top: .75rem; }
pre { background: var(--card); color: var(--text); padding: 1rem; border-radius: .8rem; overflow: auto; border:1px solid var(--border) }
code { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono","Courier New", monospace; font-size: .95em; }
.roadmap { counter-reset: step; padding-left: 1.2rem; } .roadmap li { margin: .5rem 0 } .roadmap li::marker { color: var(--brand-2) }
a { color: var(--brand-2) } a:hover { text-decoration: underline; }
@media (max-width: 720px) { .nav { display:none } }