*, *::before, *::after {
  box-sizing: border-box;
}

:root {
  --bg: #070817;
  --panel: rgba(255, 255, 255, 0.045);
  --panel-strong: rgba(255, 255, 255, 0.075);
  --line: rgba(255, 255, 255, 0.12);
  --text: #f7f7fb;
  --muted: #aeb3c7;
  --soft: #7f879f;
  --accent: #8db4ff;
  --accent-2: #d8c7ff;
}

html {
  background: var(--bg);
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at 15% 10%, rgba(141, 180, 255, 0.14), transparent 30%),
    radial-gradient(circle at 85% 5%, rgba(216, 199, 255, 0.12), transparent 28%),
    linear-gradient(180deg, #08091b 0%, #060712 100%);
  color: var(--text);
}

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

a:hover {
  text-decoration: underline;
}

.top {
  border-bottom: 1px solid var(--line);
  background: rgba(7, 8, 23, 0.78);
  backdrop-filter: blur(18px);
  position: sticky;
  top: 0;
  z-index: 2;
}

.shell {
  width: min(1080px, calc(100% - 40px));
  margin: 0 auto;
}

.top .shell {
  min-height: 70px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  color: var(--text);
  font-weight: 700;
  letter-spacing: -0.02em;
  display: inline-flex;
  flex-direction: column;
  gap: 2px;
}

.brand span {
  color: var(--soft);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav {
  display: flex;
  align-items: center;
  gap: 20px;
  font-size: 13px;
  color: var(--muted);
  flex-wrap: wrap;
  justify-content: flex-end;
}

.lang {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-left: 8px;
  padding-left: 18px;
  border-left: 1px solid var(--line);
}

.lang a {
  color: var(--soft);
}

.lang a.active {
  color: var(--text);
  font-weight: 700;
}

.hero {
  padding: 86px 0 54px;
}

.eyebrow {
  color: var(--accent-2);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  margin-bottom: 18px;
}

h1 {
  font-size: clamp(38px, 7vw, 78px);
  line-height: 0.96;
  letter-spacing: -0.04em;
  margin: 0;
  max-width: 920px;
}

.lede {
  color: var(--muted);
  font-size: clamp(16px, 2vw, 20px);
  line-height: 1.8;
  max-width: 780px;
  margin: 26px 0 0;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 28px;
}

.pill {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 12px;
  color: var(--muted);
  font-size: 12px;
  background: rgba(255, 255, 255, 0.035);
}

main {
  padding: 0 0 84px;
}

.grid {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 56px;
  align-items: start;
}

.side {
  position: sticky;
  top: 98px;
  display: grid;
  gap: 10px;
}

.side a {
  color: var(--muted);
  font-size: 14px;
  padding: 10px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
}

.content {
  display: grid;
  gap: 28px;
}

section {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  padding: clamp(24px, 4vw, 38px);
}

h2 {
  margin: 0 0 18px;
  font-size: clamp(22px, 3vw, 32px);
  letter-spacing: -0.02em;
}

h3 {
  margin: 26px 0 10px;
  font-size: 17px;
}

p, li {
  color: var(--muted);
  line-height: 1.9;
  font-size: 15px;
}

p {
  margin: 0 0 12px;
}

ul {
  padding-left: 1.3em;
  margin: 10px 0 0;
}

.table {
  display: grid;
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  margin-top: 16px;
}

.row {
  display: grid;
  grid-template-columns: 220px 1fr;
  border-bottom: 1px solid var(--line);
}

.row:last-child {
  border-bottom: 0;
}

.th, .td {
  padding: 14px 16px;
  line-height: 1.8;
  font-size: 14px;
}

.th {
  color: var(--text);
  background: var(--panel-strong);
  font-weight: 700;
}

.td {
  color: var(--muted);
}

.note {
  border-left: 3px solid var(--accent);
  padding: 12px 0 12px 16px;
  color: var(--muted);
  background: rgba(141, 180, 255, 0.055);
  margin-top: 16px;
}

footer {
  border-top: 1px solid var(--line);
  padding: 32px 0;
  color: var(--soft);
  font-size: 12px;
}

footer .shell {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

@media (max-width: 820px) {
  .top .shell {
    align-items: flex-start;
    flex-direction: column;
    padding: 18px 0;
  }

  .nav {
    flex-wrap: wrap;
    gap: 14px;
    justify-content: flex-start;
  }

  .lang {
    margin-left: 0;
    padding-left: 0;
    border-left: 0;
  }

  .grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }

  .side {
    position: static;
  }

  .row {
    grid-template-columns: 1fr;
  }

  .th {
    border-bottom: 1px solid var(--line);
  }
}