/* design: dark | 深色科技 | 近黑底 + 霓虹青，适合比赛现场演示 */
:root[data-design="dark"] {
  color-scheme: dark;
  --bg: #03070a; --panel: rgba(8, 19, 26, .86); --ink: #d6f4ff; --ink2: #8fb4c2; --muted: #5b7f8e;
  --hi: #eafaff; --rule: #123241; --rule2: #1b4658; --grid: #0b1d26;
  --neon: #1fe0ff; --neon-rgb: 31, 224, 255; --neon2: #2bffa8;
  --deep: #061219; --deep-rgb: 6, 18, 25; --glow: 0 0 8px rgba(31,224,255,.55);
  --bg-img: radial-gradient(1100px 600px at 50% -10%, rgba(31,224,255,.12), transparent 65%),
            radial-gradient(900px 500px at 95% 110%, rgba(43,255,168,.07), transparent 60%),
            linear-gradient(rgba(31,224,255,.028) 1px, transparent 1px),
            linear-gradient(90deg, rgba(31,224,255,.028) 1px, transparent 1px);
  --bg-size: auto, auto, 44px 44px, 44px 44px;
  --top-bg: linear-gradient(180deg, rgba(6,20,30,.98), rgba(4,12,18,.9));
  --top-line: linear-gradient(90deg, transparent, #1fe0ff, transparent);
  --title: #eafaff; --title-glow: 0 0 18px rgba(31,224,255,.55);
  --status-bg: #040d13; --panel-shadow: inset 0 0 40px rgba(31,224,255,.03);
  --corner: #1fe0ff; --corner-op: .55; --head-bg: rgba(12,32,42,.65);
  --nav-bg: rgba(6,20,28,.8); --nav-hover: rgba(31,224,255,.08); --nav-on: #1fe0ff; --nav-on-ink: #03131a;
  --nav-on-glow: 0 0 10px rgba(31,224,255,.7);
  --stat-bg: rgba(10,26,34,.7); --kpi-bg: linear-gradient(180deg, rgba(12,34,46,.75), rgba(6,18,25,.6));
  --track: #0d2530; --hover: rgba(31,224,255,.06); --thead: rgba(15,38,49,.7);
  --chip-bg: rgba(9,24,32,.85); --btn-bg: rgba(9,24,32,.85); --btn-primary-ink: #03131a;
  --judge-bg: rgba(3,12,17,.82); --code-bg: rgba(5,17,23,.8); --drop-bg: rgba(6,18,25,.55);
  --gw: #3fa9ff; --gw-soft: rgba(63,169,255,.6); --lc: #ff9a3c; --lc-soft: rgba(255,154,60,.6);
  --plan: #2bffa8; --rain: #58c8ff; --crit: #ff4d5e; --crit-bg: rgba(255,77,94,.12); --crit-line: rgba(255,77,94,.5);
  --warn: #ffb23f; --warn-bg: rgba(255,178,63,.12); --warn-line: rgba(255,178,63,.45);
  --good: #2bffa8; --good-bg: rgba(43,255,168,.1); --good-line: rgba(43,255,168,.4);
  --neon-bg: rgba(31,224,255,.1); --neon-line: rgba(31,224,255,.45);
  --wall: #7fd4ff; --sky: #07131f; --terr-lo: #2d5a58; --terr-hi: #9bb878; --terr-in: #7a6040;
  --waste: #5a4632; --soil: #3a332a; --rock: #23343b; --wall-line: #7fd4ff; --ditch: #3f7d8f;
  --zone: #9fc6d2; --contour-major: #2a5a6a; --contour-minor: #1a3b47;
  --fx-a: .5; --scan: .5; --stage-grad: linear-gradient(180deg, #04101a 0%, #040b16 60%, #03070a 100%);
}
:root[data-design="dark"] .topbar { box-shadow: 0 1px 18px rgba(0,0,0,.65); }
:root[data-design="dark"] .topbar::before {
  content: ""; position: absolute; left: 50%; top: 0; transform: translateX(-50%);
  width: 520px; height: 1px; background: linear-gradient(90deg, transparent, #1fe0ff, transparent);
}
:root[data-design="dark"] .panel { backdrop-filter: blur(4px); }
:root[data-design="dark"] .stage { background: var(--stage-grad); }
:root[data-design="dark"] .site-stat { background: linear-gradient(135deg, rgba(31,224,255,.07), transparent 70%), rgba(10,26,34,.7); }
:root[data-design="dark"] .kpi { box-shadow: inset 0 0 18px rgba(31,224,255,.05); }