:root { --bg: #15181d; --panel: #1e232a; --line: #2e353f; --fg: #e9e6df; --muted: #9aa3ad; --accent: #f0a640; --side: 250px; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 16px/1.55 system-ui, -apple-system, "Segoe UI", sans-serif; }
a { color: var(--accent); }

/* ---- layout: side menu + content ---- */
.side { position: fixed; inset: 0 auto 0 0; width: var(--side); background: var(--panel); border-right: 1px solid var(--line); padding: 20px 14px; overflow-y: auto; z-index: 20; }
.side .brand { display: block; font-weight: 700; font-size: 18px; color: var(--fg); text-decoration: none; margin: 0 8px 18px; letter-spacing: -.01em; }
.side .brand span { color: var(--accent); }
.side h4 { margin: 18px 8px 4px; font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); font-weight: 600; }
.side a.item { display: block; padding: 6px 10px; border-radius: 6px; color: var(--fg); text-decoration: none; }
.side a.item:hover { background: rgba(255, 255, 255, .06); }
.side a.item[aria-current="page"] { background: var(--accent); color: #1b1408; font-weight: 600; }
.menu-btn { display: none; position: fixed; top: 10px; left: 10px; z-index: 30; font: inherit; color: var(--fg); background: var(--panel); border: 1px solid var(--line); border-radius: 8px; padding: 6px 12px; cursor: pointer; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 24px 20px 48px; margin-left: var(--side); }
@media (min-width: 1500px) { .wrap { margin: 0 auto; padding-left: calc(var(--side) + 20px); } }
@media (max-width: 860px) {
  .side { transform: translateX(-100%); transition: transform .2s; }
  .side.open { transform: none; box-shadow: 0 0 40px rgba(0, 0, 0, .6); }
  .menu-btn { display: block; }
  .wrap { margin-left: 0; padding-top: 56px; }
}

header h1 { margin: 0; font-size: 34px; letter-spacing: -.01em; }
header p { margin: 4px 0 0; color: var(--muted); }
@media (max-width: 860px) { header h1 { font-size: 28px; } }

/* ---- 3D viewer pages ---- */
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0 12px; }
.tabs button { font: inherit; color: var(--fg); background: var(--panel); border: 1px solid var(--line); border-radius: 999px; padding: 7px 16px; cursor: pointer; }
.tabs button:hover { border-color: var(--muted); }
.tabs button[aria-selected="true"] { background: var(--accent); border-color: var(--accent); color: #1b1408; font-weight: 600; }
.main { display: grid; grid-template-columns: minmax(0, 1.55fr) minmax(300px, 1fr); gap: 18px; align-items: start; margin-top: 22px; }
.tabs + .main { margin-top: 0; }
@media (max-width: 1100px) { .main { grid-template-columns: 1fr; } }
.viewer { background: linear-gradient(#9cc3e6, #dfeaf3); border-radius: 10px; overflow: hidden; position: relative; aspect-ratio: 4 / 3; }
.viewer canvas { display: block; width: 100%; height: 100%; touch-action: none; cursor: grab; }
.viewer canvas:active { cursor: grabbing; }
.tools { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 10px; color: var(--muted); font-size: 14px; }
.tools button, .tools select { font: inherit; color: var(--fg); background: var(--panel); border: 1px solid var(--line); border-radius: 6px; padding: 5px 10px; cursor: pointer; }
.tools button[aria-pressed="true"] { border-color: var(--accent); }
.tools label { display: inline-flex; align-items: center; gap: 6px; color: var(--fg); }
.tools .hint { width: 100%; }
.info { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 18px 20px; }
.info h2 { margin: 0; font-size: 24px; }
.info .sub { color: var(--accent); margin: 0 0 10px; }
.info h3 { margin: 14px 0 2px; font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); }
.info p { margin: 0; }
.warn { margin-top: 14px; padding: 10px 12px; border-left: 3px solid var(--accent); background: rgba(240, 166, 64, .08); border-radius: 4px; }

/* ---- article ---- */
section { margin-top: 40px; }
section h2 { font-size: 24px; margin: 0 0 10px; }
section li { margin: 6px 0; }
.radar { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 16px 20px; margin-top: 12px; }
.radar input { width: 100%; accent-color: var(--accent); }
.radar .out { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; margin-top: 6px; }
.radar .msg { font-weight: 600; transition: color .2s; }
footer { margin-top: 48px; color: var(--muted); font-size: 14px; border-top: 1px solid var(--line); padding-top: 14px; }
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; margin-top: 22px; }
.card { display: block; background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 16px 18px; color: var(--fg); text-decoration: none; }
.card:hover { border-color: var(--accent); }
.card b { display: block; font-size: 18px; margin-bottom: 4px; }
.card span { color: var(--muted); font-size: 14px; }
code, kbd { background: rgba(255, 255, 255, .08); border-radius: 4px; padding: 1px 5px; font-size: .92em; }