:root{
  --bg:#f5f7fb;
  --card:#ffffff;
  --text:#111827;
  --muted:#6b7280;
  --border:#e5e7eb;
  --link:#2563eb;
  --max:900px;
}

*{ box-sizing:border-box; }

body{
  margin:0;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Hiragino Kaku Gothic ProN",Meiryo,sans-serif;
  background:var(--bg);
  color:var(--text);
}

.header{
  border-bottom:1px solid var(--border);
  background:rgba(255,255,255,.85);
  backdrop-filter:saturate(180%) blur(10px);
  position:sticky;
  top:0;
  z-index:10;
}

.header-inner{
  max-width:var(--max);
  margin:0 auto;
  padding:14px 16px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
}

.brand{
  font-weight:800;
  letter-spacing:.2px;
}

.brand a{
  color:var(--text);
  text-decoration:none;
}

.nav{
  display:flex;
  gap:10px;
  flex-wrap:wrap;
  justify-content:flex-end;
  font-size:13px;
}

.nav a{
  color:var(--muted);
  text-decoration:none;
  padding:6px 8px;
  border-radius:10px;
}
.nav a:hover{
  background:#f1f5f9;
  color:var(--text);
}

.container{
  max-width:var(--max);
  margin:0 auto;
  padding:22px 16px 40px;
}

.card{
  background:var(--card);
  border:1px solid var(--border);
  border-radius:18px;
  padding:22px 22px;
  box-shadow:0 16px 30px rgba(15,23,42,.10);
}

h1{
  font-size:26px;
  margin:0 0 10px;
}

.meta{
  font-size:13px;
  color:var(--muted);
  margin:0 0 18px;
}

h2{
  font-size:18px;
  margin:22px 0 10px;
}

p, li{
  line-height:1.75;
  font-size:15px;
}

ul{
  margin:10px 0 0 18px;
}

hr{
  border:0;
  border-top:1px solid var(--border);
  margin:22px 0;
}

.footer{
  margin-top:18px;
  font-size:12px;
  color:var(--muted);
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  justify-content:space-between;
  align-items:center;
}

.footer a{
  color:var(--muted);
  text-decoration:none;
}
.footer a:hover{ text-decoration:underline; }

.badge{
  display:inline-block;
  font-size:12px;
  padding:4px 10px;
  border-radius:999px;
  background:#eef2ff;
  color:#3730a3;
  border:1px solid #e0e7ff;
}