:root{
  --bg:#0b0f14;
  --card:#121925;
  --text:#e8eef7;
  --muted:#a9b4c3;
  --line:#233044;
  --accent:#4da3ff;
  --accent2:#9dffb0;
  --shadow: 0 10px 30px rgba(0,0,0,.35);
  --r: 18px;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family: ui-sans-serif, system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP", "Segoe UI", Arial;
  background: radial-gradient(1200px 600px at 20% 0%, rgba(77,163,255,.18), transparent 60%),
              radial-gradient(900px 500px at 80% 10%, rgba(157,255,176,.14), transparent 60%),
              var(--bg);
  color:var(--text);
}

a{color:inherit}
.container{max-width:980px;margin:0 auto;padding:20px}
.header{
  display:flex;align-items:center;justify-content:space-between;
  position:sticky;top:0;background:rgba(11,15,20,.75);backdrop-filter: blur(10px);
  border-bottom:1px solid rgba(35,48,68,.7);
  z-index:10;
}
.brand{font-weight:800;letter-spacing:.02em}
.nav{display:flex;gap:14px}
.nav a{
  text-decoration:none;color:var(--muted);
  padding:8px 10px;border-radius:10px;
}
.nav a:hover{background:rgba(35,48,68,.5);color:var(--text)}

.hero{
  margin-top:10px;
  padding:26px;
  border:1px solid rgba(35,48,68,.8);
  border-radius: var(--r);
  background: linear-gradient(180deg, rgba(18,25,37,.9), rgba(18,25,37,.55));
  box-shadow: var(--shadow);
}
h1{font-size:42px;margin:0 0 10px}
.lead{color:var(--muted);line-height:1.7;margin:0 0 18px}
.cta{display:flex;gap:10px;flex-wrap:wrap}
.btn{
  border:1px solid rgba(35,48,68,.9);
  background:rgba(11,15,20,.55);
  color:var(--text);
  padding:10px 14px;
  border-radius: 12px;
  cursor:pointer;
}
.btn:hover{background:rgba(35,48,68,.6)}
.primary{
  border-color: rgba(77,163,255,.8);
  background: rgba(77,163,255,.18);
}
.note{margin:14px 0 0;color:var(--muted);font-size:12px}

.grid{
  display:grid;
  grid-template-columns: repeat(3, 1fr);
  gap:14px;
  margin-top:16px;
}
.card{
  padding:16px;
  border-radius: var(--r);
  border:1px solid rgba(35,48,68,.85);
  background:rgba(18,25,37,.55);
}
.card h2{margin:0 0 6px;font-size:18px}
.card p{margin:0;color:var(--muted);line-height:1.6}

.section{margin-top:26px}
.section h2{margin:0 0 8px}
.sub{margin:0 0 12px;color:var(--muted)}

.list{list-style:none;padding:0;margin:0;display:grid;gap:10px}
.list li{
  display:flex;align-items:center;justify-content:space-between;gap:10px;
  padding:12px 14px;border-radius: 14px;
  border:1px solid rgba(35,48,68,.85);
  background:rgba(18,25,37,.45);
}
.list a{text-decoration:none}
.list a:hover{text-decoration:underline}
.tag{
  font-size:12px;color:var(--muted);
  border:1px solid rgba(35,48,68,.85);
  padding:4px 8px;border-radius:999px;
}

.mini{
  margin-top:16px;
  padding:14px;
  border-radius: var(--r);
  border:1px dashed rgba(35,48,68,.95);
  color:var(--muted);
}
.mini h3{margin:0 0 8px;color:var(--text);font-size:16px}
.mini ol{margin:0;padding-left:18px}
.mini li{margin:6px 0}

.details{
  margin-top:10px;
  border:1px solid rgba(35,48,68,.85);
  border-radius: var(--r);
  padding:12px 14px;
  background:rgba(18,25,37,.45);
}
.details summary{cursor:pointer;color:var(--text)}
.footer{margin:26px 0 10px;color:var(--muted);text-align:center}

@media (max-width: 820px){
  h1{font-size:34px}
  .grid{grid-template-columns: 1fr}
  .header{gap:10px}
}