:root{
  --bg: #ffffff;
  --bg2:#f7f7fb;
  --card:#ffffff;
  --text:#0b1020;
  --muted:#4b5563;
  --border:#e5e7eb;
  --shadow: 0 10px 30px rgba(0,0,0,.06);
  --accent:#2563eb;
  --accent2:#7c3aed;
  --good:#16a34a;
  --warn:#ea580c;
  --bad:#dc2626;
  --link:#2563eb;
  --codebg:#0b1020;
  --codetext:#f9fafb;
  --radius:16px;
  --radius-sm:12px;
  --max: 1120px;
  --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, Arial, "Noto Sans", "Helvetica Neue", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

[data-theme="dark"]{
  --bg:#0b1020;
  --bg2:#0f172a;
  --card:#0b1226;
  --text:#eef2ff;
  --muted:#b6c0d1;
  --border:#1f2a44;
  --shadow: 0 16px 40px rgba(0,0,0,.35);
  --link:#60a5fa;
  --codebg:#030712;
  --codetext:#e5e7eb;
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family:var(--font);
  background: radial-gradient(1200px 600px at 20% -10%, rgba(37,99,235,.16), transparent 60%),
              radial-gradient(900px 600px at 85% 0%, rgba(124,58,237,.14), transparent 55%),
              linear-gradient(180deg, var(--bg), var(--bg2));
  color:var(--text);
  line-height:1.5;
}

a{color:var(--link); text-decoration:none}
a:hover{text-decoration:underline}

.container{max-width:var(--max); margin:0 auto; padding:0 20px}
.header{
  position:sticky; top:0; z-index:50;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  border-bottom:1px solid var(--border);
}
.header-inner{
  display:flex; align-items:center; justify-content:space-between;
  padding:14px 0;
  gap:16px;
}
.brand{
  display:flex; align-items:center; gap:10px;
  font-weight:800; letter-spacing:.5px;
}
.brand .logo{
  width:34px; height:34px; border-radius:10px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  box-shadow: var(--shadow);
}
.nav{
  display:flex; gap:14px; flex-wrap:wrap;
  align-items:center;
}
.nav a{
  color:var(--text);
  padding:8px 10px;
  border-radius:10px;
  border:1px solid transparent;
}
.nav a:hover{
  text-decoration:none;
  background: color-mix(in srgb, var(--bg2) 80%, transparent);
  border-color: var(--border);
}
.nav a.active{
  background: color-mix(in srgb, var(--bg2) 85%, transparent);
  border-color: var(--border);
}

.header-actions{display:flex; gap:10px; align-items:center}
.btn{
  display:inline-flex; align-items:center; justify-content:center;
  padding:10px 14px;
  border-radius:12px;
  border:1px solid var(--border);
  background: color-mix(in srgb, var(--card) 92%, transparent);
  color:var(--text);
  box-shadow: none;
  cursor:pointer;
  font-weight:600;
}
.btn:hover{filter:brightness(1.02)}
.btn.primary{
  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 92%, white), color-mix(in srgb, var(--accent2) 85%, white));
  color:#fff;
}
.btn.ghost{
  background:transparent;
}
.pill{
  display:inline-flex; gap:8px; align-items:center;
  font-size:12px;
  padding:6px 10px;
  border-radius:999px;
  border:1px solid var(--border);
  background: color-mix(in srgb, var(--bg2) 70%, transparent);
  color:var(--muted);
}

.main{padding:28px 0 56px}

.hero{
  display:grid; grid-template-columns: 1.2fr .8fr;
  gap:22px;
  align-items:stretch;
}
@media (max-width: 960px){
  .hero{grid-template-columns:1fr}
  .nav{display:none}
}
.card{
  background: color-mix(in srgb, var(--card) 92%, transparent);
  border:1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.card.pad{padding:22px}
.card.pad-lg{padding:28px}
.h1{font-size:44px; line-height:1.08; margin:0 0 10px; letter-spacing:-.8px}
@media (max-width: 960px){.h1{font-size:36px}}
.lead{font-size:16px; color:var(--muted); margin:0 0 16px}
.grid3{display:grid; grid-template-columns:repeat(3,1fr); gap:14px}
@media (max-width: 960px){.grid3{grid-template-columns:1fr}}
.grid2{display:grid; grid-template-columns:repeat(2,1fr); gap:14px}
@media (max-width: 960px){.grid2{grid-template-columns:1fr}}
.kpi{
  padding:14px;
  border-radius: var(--radius-sm);
  border:1px solid var(--border);
  background: color-mix(in srgb, var(--bg2) 65%, transparent);
}
.kpi b{display:block; font-size:14px}
.kpi span{color:var(--muted); font-size:12px}
.section{margin-top:18px}
.section h2{margin:0 0 10px; font-size:20px}
.section p{margin:0; color:var(--muted)}

.footer{
  border-top:1px solid var(--border);
  padding:22px 0 40px;
  color:var(--muted);
}
.footer a{color:var(--muted)}
.footer a:hover{color:var(--text)}
.footer-grid{display:grid; grid-template-columns: 1fr 1fr; gap:16px}
@media (max-width: 960px){.footer-grid{grid-template-columns:1fr}}

.notice{
  padding:14px 16px;
  border-radius: var(--radius-sm);
  border:1px dashed color-mix(in srgb, var(--border) 80%, var(--accent) 25%);
  background: color-mix(in srgb, var(--bg2) 80%, transparent);
  color:var(--muted);
  font-size:13px;
}

.small{font-size:13px; color:var(--muted)}
.hr{height:1px; background:var(--border); margin:16px 0}

.badge{
  display:inline-flex; align-items:center; justify-content:center;
  padding:4px 10px; border-radius:999px;
  background: color-mix(in srgb, var(--bg2) 75%, transparent);
  border:1px solid var(--border);
  font-size:12px; color:var(--muted);
}
.tag{
  display:inline-flex; align-items:center; justify-content:center;
  padding:3px 8px; border-radius:999px;
  background: color-mix(in srgb, var(--accent) 14%, transparent);
  border:1px solid color-mix(in srgb, var(--accent) 18%, var(--border));
  color: color-mix(in srgb, var(--accent) 85%, var(--text));
  font-size:12px;
}

.ad{
  border:1px dashed color-mix(in srgb, var(--border) 85%, #aaa 15%);
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--bg2) 75%, transparent);
  padding:12px;
  color:var(--muted);
  font-size:12px;
}
.ad .title{font-weight:700; color:var(--text); margin-bottom:6px}

.layout-two{
  display:grid; grid-template-columns: 1fr 320px; gap:16px;
}
@media (max-width: 960px){.layout-two{grid-template-columns:1fr}}

.test-shell{
  display:flex; flex-direction:column; gap:12px;
}
.qprompt{
  font-size:16px;
}
.choices{display:grid; grid-template-columns: 1fr 1fr; gap:10px}
@media (max-width: 700px){.choices{grid-template-columns:1fr}}
.choice{
  text-align:left;
  padding:12px 12px;
  border-radius: var(--radius-sm);
  border:1px solid var(--border);
  background: color-mix(in srgb, var(--card) 94%, transparent);
  cursor:pointer;
  font-weight:600;
}
.choice:hover{filter:brightness(1.02)}
.choice.correct{border-color: color-mix(in srgb, var(--good) 55%, var(--border)); background: color-mix(in srgb, var(--good) 10%, var(--card))}
.choice.wrong{border-color: color-mix(in srgb, var(--bad) 55%, var(--border)); background: color-mix(in srgb, var(--bad) 8%, var(--card))}

.progress{
  display:flex; align-items:center; justify-content:space-between; gap:10px;
  color:var(--muted); font-size:13px;
}
.bar{
  height:10px; border-radius:999px; background: color-mix(in srgb, var(--bg2) 80%, transparent);
  border:1px solid var(--border);
  overflow:hidden;
}
.bar > div{
  height:100%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  width:0%;
}

.matrix-grid{
  display:grid; grid-template-columns: repeat(3, 1fr); gap:8px;
}
.matrix-cell{
  aspect-ratio:1/1;
  border:1px solid var(--border);
  border-radius: 10px;
  background: color-mix(in srgb, var(--bg2) 75%, transparent);
  display:flex; align-items:center; justify-content:center;
  overflow:hidden;
}
.matrix-cell svg{width:90%; height:90%}
.matrix-missing{
  border-style:dashed;
  color:var(--muted);
  font-weight:800;
}

.codebox{
  font-family: var(--mono);
  font-size:12px;
  padding:12px;
  border-radius: var(--radius-sm);
  background: var(--codebg);
  color: var(--codetext);
  border: 1px solid color-mix(in srgb, var(--border) 30%, #000);
  overflow:auto;
}

.modal-backdrop{
  position:fixed; inset:0; z-index:1000;
  display:none;
  background: rgba(0,0,0,.55);
  padding:18px;
}
.modal{
  max-width:560px;
  margin:8vh auto 0;
  background: var(--card);
  border-radius: var(--radius);
  border:1px solid var(--border);
  box-shadow: var(--shadow);
  padding:20px;
}
.modal h3{margin:0 0 8px}
.modal p{margin:0 0 12px; color:var(--muted)}
.modal .actions{display:flex; gap:10px; flex-wrap:wrap}

.toast{
  position:fixed; right:16px; bottom:16px; z-index:1200;
  display:none;
  background: var(--card);
  border:1px solid var(--border);
  border-radius:14px;
  box-shadow: var(--shadow);
  padding:12px 14px;
  max-width: 360px;
}
.toast b{display:block; margin-bottom:2px}
.toast span{color:var(--muted); font-size:13px}

.choice svg{width:100%; height:110px}
.matrix-cell svg{color:var(--text)}