:root {
  --bg: #070b1a;
  --bg-2: #0c1330;
  --panel: rgba(18, 28, 64, 0.72);
  --line: rgba(120, 150, 255, 0.18);
  --text: #e8ecf8;
  --muted: #9aa6c8;
  --accent: #4d8dff;
  --accent-2: #7fb2ff;
  --warm: #ffb45c;
  --radius: 14px;
  color-scheme: dark;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(77, 141, 255, 0.18), transparent 60%),
    radial-gradient(900px 500px at -10% 10%, rgba(255, 90, 140, 0.08), transparent 60%),
    linear-gradient(180deg, var(--bg-2), var(--bg) 480px);
  background-color: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN",
    "Noto Sans JP", "Segoe UI", Roboto, "Yu Gothic UI", Meiryo, sans-serif;
  font-size: 16px;
  line-height: 1.8;
  min-height: 100vh;
}

a { color: var(--accent-2); text-underline-offset: 3px; }
a:hover { color: #fff; }

.wrap { max-width: 820px; margin: 0 auto; padding: 0 16px; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 10;
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  background: rgba(7, 11, 26, 0.72);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; min-height: 60px;
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); }
.brand img { width: 34px; height: 34px; border-radius: 8px; }
.brand span { font-weight: 800; letter-spacing: 0.06em; font-size: 15px; white-space: nowrap; }
.site-nav { display: flex; gap: 4px; flex-wrap: wrap; justify-content: flex-end; }
.site-nav a {
  color: var(--muted); text-decoration: none; font-size: 14px;
  padding: 6px 10px; border-radius: 8px;
}
.site-nav a:hover, .site-nav a[aria-current="page"] { color: #fff; background: rgba(77, 141, 255, 0.16); }

/* ---------- page title ---------- */
.page-head { padding: 48px 0 24px; }
.page-head .eyebrow {
  color: var(--accent-2); font-size: 13px; font-weight: 700; letter-spacing: 0.18em; text-transform: uppercase;
}
.page-head h1 { margin: 6px 0 8px; font-size: clamp(28px, 6vw, 40px); line-height: 1.25; }
.page-head .meta { color: var(--muted); font-size: 14px; margin: 0; }

.lang-switch { display: inline-flex; gap: 6px; margin-top: 18px; }
.lang-switch a {
  font-size: 13px; text-decoration: none; color: var(--text);
  border: 1px solid var(--line); border-radius: 999px; padding: 4px 14px;
}
.lang-switch a:hover { border-color: var(--accent); }

/* ---------- content ---------- */
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 8px 24px 20px;
  margin-bottom: 28px;
}
.card + .lang-divider { margin-top: 40px; }

section.lang { padding-bottom: 8px; scroll-margin-top: 72px; }
.lang-divider {
  display: flex; align-items: center; gap: 12px;
  color: var(--muted); font-size: 12px; letter-spacing: 0.2em; text-transform: uppercase;
  margin: 48px 0 8px;
}
.lang-divider::before, .lang-divider::after { content: ""; flex: 1; height: 1px; background: var(--line); }

h2 {
  font-size: 19px; margin: 28px 0 8px; padding-top: 4px;
  display: flex; align-items: baseline; gap: 10px;
}
h2 .num { color: var(--accent); font-variant-numeric: tabular-nums; font-size: 15px; }
h3 { font-size: 16px; margin: 20px 0 4px; }
p { margin: 8px 0; }
ul { margin: 8px 0; padding-left: 1.3em; }
li { margin: 4px 0; }
li::marker { color: var(--accent); }
strong { color: #fff; }

.summary {
  border-left: 3px solid var(--accent);
  background: rgba(77, 141, 255, 0.08);
  border-radius: 0 10px 10px 0;
  padding: 12px 16px; margin: 20px 0 4px;
}
.summary p { margin: 0; }

.kbd {
  display: inline-block; font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.86em; letter-spacing: 0.04em; overflow-wrap: anywhere;
  -webkit-box-decoration-break: clone; box-decoration-break: clone;
  padding: 1px 7px; border-radius: 6px;
  background: rgba(255, 255, 255, 0.08); border: 1px solid var(--line); color: #fff;
}

/* ---------- contact box ---------- */
.contact {
  display: grid; gap: 6px;
  background: linear-gradient(135deg, rgba(77, 141, 255, 0.2), rgba(77, 141, 255, 0.05));
  border: 1px solid rgba(77, 141, 255, 0.45);
  border-radius: var(--radius); padding: 20px 22px; margin: 16px 0 8px;
}
.contact .label { color: var(--muted); font-size: 13px; }
.contact .mail {
  font-size: clamp(16px, 4.6vw, 21px); font-weight: 700; color: #fff; text-decoration: none;
  overflow-wrap: anywhere;
}
.contact .mail:hover { text-decoration: underline; }

/* ---------- FAQ ---------- */
details {
  border: 1px solid var(--line); border-radius: 12px;
  background: rgba(255, 255, 255, 0.02);
  margin: 10px 0; padding: 0 16px;
}
details[open] { background: rgba(77, 141, 255, 0.06); }
summary {
  cursor: pointer; list-style: none; font-weight: 700;
  padding: 14px 28px 14px 0; position: relative;
}
summary::-webkit-details-marker { display: none; }
summary::after {
  content: "+"; position: absolute; right: 0; top: 50%; transform: translateY(-50%);
  color: var(--accent); font-size: 22px; font-weight: 400;
}
details[open] summary::after { content: "\2212"; }
details > *:not(summary) { margin-top: 0; }
details > :last-child { padding-bottom: 14px; }

/* ---------- landing ---------- */
.hero {
  position: relative; overflow: hidden;
  border-radius: 0 0 28px 28px;
  min-height: min(72vh, 620px);
  display: flex; align-items: flex-end;
  background: #000 url("img/hero.jpg") center 40% / cover no-repeat;
}
.hero::after {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(7, 11, 26, 0.1) 30%, rgba(7, 11, 26, 0.92));
}
.hero .wrap { position: relative; z-index: 1; padding-bottom: 40px; width: 100%; }
.hero .logo { width: min(460px, 86%); height: auto; display: block; filter: drop-shadow(0 4px 18px rgba(0, 0, 0, 0.6)); }
.hero p { color: #d7def5; font-size: 17px; max-width: 34em; margin-top: 14px; }

.links { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 32px 0; }
.link-card {
  display: block; text-decoration: none; color: var(--text);
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px;
}
.link-card:hover { border-color: var(--accent); color: var(--text); }
.link-card .t { font-weight: 800; font-size: 17px; }
.link-card .d { color: var(--muted); font-size: 14px; margin-top: 2px; }

.facts { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0 0; padding: 0; list-style: none; }
.facts li {
  font-size: 12px; font-weight: 700; letter-spacing: 0.12em;
  border: 1px solid rgba(255, 255, 255, 0.28); border-radius: 999px; padding: 3px 12px;
  background: rgba(0, 0, 0, 0.35);
}

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--line); margin-top: 56px; padding: 28px 0 40px;
  color: var(--muted); font-size: 13px;
}
.site-footer .wrap { display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between; }
.site-footer nav { display: flex; gap: 16px; flex-wrap: wrap; }
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: #fff; }

@media (max-width: 520px) {
  .brand span { display: none; }
  .card { padding: 4px 16px 16px; }
  .page-head { padding-top: 36px; }
}