:root {
  --bg: #0b0f14;
  --panel: #141b24;
  --panel-2: #1c2530;
  --border: #2a3440;
  --text: #e6edf3;
  --muted: #9aa5b1;
  --accent: #4ea1ff;
  --accent-2: #7bd4ff;
  --ok: #3fb950;
  --warn: #d29922;
  --danger: #f85149;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Noto Sans JP", system-ui, -apple-system, "Hiragino Kaku Gothic ProN", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: 980px; margin: 0 auto; padding: 0 20px; }

/* ヘッダー */
header.site {
  position: sticky; top: 0; z-index: 10;
  background: rgba(11, 15, 20, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
header.site .container { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.logo { font-size: 1.4rem; font-weight: 800; letter-spacing: 0.04em; }
.logo span { color: var(--accent); }
header.site nav a { color: var(--muted); margin-left: 1.25rem; font-size: 0.9rem; }
header.site nav a:hover { color: var(--text); text-decoration: none; }

/* ヒーロー */
.hero { padding: 72px 0 56px; text-align: center; }
.hero h1 { font-size: 2.6rem; margin: 0 0 0.5rem; letter-spacing: 0.02em; }
.hero .tagline { font-size: 1.15rem; color: var(--muted); margin: 0 0 2rem; }
.hero .cta { display: inline-flex; gap: 0.75rem; flex-wrap: wrap; justify-content: center; }

.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.8rem 1.6rem; border-radius: 10px; font-weight: 700; font-size: 1rem;
  border: 1px solid var(--border); background: var(--panel-2); color: var(--text);
  cursor: pointer; transition: transform 0.08s ease, filter 0.15s ease;
}
.btn:hover { text-decoration: none; filter: brightness(1.12); transform: translateY(-1px); }
.btn.primary { background: var(--accent); color: #04111f; border-color: transparent; }
.btn.lg { padding: 1rem 2rem; font-size: 1.05rem; }
.btn.disabled { opacity: 0.5; pointer-events: none; cursor: default; filter: grayscale(0.4); }

/* セクション */
section { padding: 48px 0; border-top: 1px solid var(--border); }
section h2 { font-size: 1.6rem; margin: 0 0 1.5rem; }
.lead { color: var(--muted); font-size: 1.05rem; max-width: 760px; }

.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; }
.card {
  background: var(--panel); border: 1px solid var(--border); border-radius: 14px; padding: 1.4rem;
}
.card h3 { margin: 0 0 0.5rem; font-size: 1.1rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.92rem; }
.card .ico { font-size: 1.6rem; margin-bottom: 0.6rem; }

/* 注意ボックス */
.notice {
  background: rgba(78, 161, 255, 0.07);
  border: 1px solid var(--accent);
  border-radius: 12px; padding: 1.1rem 1.3rem; font-size: 0.95rem;
}
.notice.warn { background: rgba(210, 153, 34, 0.08); border-color: var(--warn); }
.notice strong { color: var(--text); }

/* ダウンロード */
.dl-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1.25rem; }
.dl-card {
  background: var(--panel); border: 1px solid var(--border); border-radius: 16px;
  padding: 1.6rem; text-align: center;
}
.dl-card .os { font-size: 2.2rem; margin-bottom: 0.5rem; }
.dl-card h3 { margin: 0 0 0.25rem; font-size: 1.25rem; }
.dl-card .ver { color: var(--muted); font-size: 0.85rem; margin-bottom: 1rem; }
.dl-card .btn { width: 100%; justify-content: center; margin-bottom: 0.5rem; }
.dl-meta { color: var(--muted); font-size: 0.78rem; margin-top: 0.75rem; word-break: break-all; }
.dl-meta code { background: var(--panel-2); padding: 0.1rem 0.35rem; border-radius: 4px; font-size: 0.72rem; }

/* フッター */
footer.site { border-top: 1px solid var(--border); padding: 32px 0; color: var(--muted); font-size: 0.85rem; }
footer.site .container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem; }

@media (max-width: 640px) {
  .hero h1 { font-size: 2rem; }
  header.site nav { display: none; }
}