:root{
  --bg:#c6ccd7;
  --card:#ffffff;
  --text:#111827;
  --muted:#4b5563;
  --border:#e5e7eb;
  --primary:#2563eb;
  --primary-hover:#1d4ed8;
  --shadow:0 10px 25px rgba(0,0,0,.08);
  --radius:14px;
}

*{box-sizing:border-box;}
html,body{height:100%;}
body{
  margin:0;
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,"Noto Sans JP",sans-serif;
  color:var(--text);
  background:var(--bg);
  line-height:1.7;
}

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

.container{
  width:min(960px, 92vw);
  margin:0 auto;
}

.skip-link{
  position:absolute;
  left:-9999px;
  top:auto;
  width:1px;
  height:1px;
  overflow:hidden;
}
.skip-link:focus{
  left:16px;
  top:16px;
  width:auto;
  height:auto;
  padding:10px 12px;
  background:var(--card);
  border:1px solid var(--border);
  border-radius:10px;
  box-shadow:var(--shadow);
  z-index:999;
}

.site-header{
  padding:48px 0 28px;
  background:linear-gradient(180deg, #ffffff 0%, rgba(255,255,255,.7) 100%);
  border-bottom:1px solid var(--border);
}

.site-title{
  margin:0 0 6px;
  font-size:clamp(24px, 3vw, 34px);
  letter-spacing:.02em;
}

.site-subtitle{
  margin:0 0 18px;
  color:var(--muted);
}

.card{
  margin:22px 0;
  padding:22px;
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  box-shadow:var(--shadow);
}

.card h2{
  margin:0 0 14px;
  font-size:20px;
}

.update + .update{
  margin-top:18px;
  padding-top:18px;
  border-top:1px solid var(--border);
}

.update h3{
  margin:0 0 6px;
  font-size:16px;
}

.update p{margin:0 0 8px; color:var(--muted);}

ul{margin:0; padding-left:1.2em;}
li{margin:4px 0;}

.cta-row{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  align-items:center;
  margin-top:14px;
}

.button{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  padding:10px 14px;
  border-radius:12px;
  border:1px solid transparent;
  background:var(--primary);
  color:#fff;
  font-weight:600;
  text-decoration:none;
  transition:transform .02s ease, background .15s ease;
}
.button:hover{
  background:var(--primary-hover);
  text-decoration:none;
}
.button:active{transform:translateY(1px);}

.button.button-secondary{
  background:#111827;
}
.button.button-secondary:hover{
  background:#0b1220;
}

.note{
  margin-top:16px;
  padding:14px 14px;
  border-radius:12px;
  background:#f3f4f6;
  border:1px solid var(--border);
  color:#111827;
}

.note-title{
  font-weight:700;
  margin-bottom:4px;
}

.page-top{
  padding:14px 0 38px;
  text-align:right;
}

.site-footer{
  padding:26px 0 40px;
  color:var(--muted);
}

.site-footer small{font-size:12px;}

@media (prefers-reduced-motion: reduce){
  *{scroll-behavior:auto;}
  .button{transition:none;}
}