:root {
  color-scheme: dark;
  --bg: #020b1b;
  --surface: rgba(10, 28, 49, 0.82);
  --surface-strong: #0a1d31;
  --line: rgba(152, 190, 218, 0.18);
  --text: #f4f8fc;
  --muted: #9db0c3;
  --blue: #41c8ec;
  --blue-strong: #1aa5d3;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(circle at 10% 0%, rgba(40, 187, 220, 0.28), transparent 34rem),
    radial-gradient(circle at 100% 90%, rgba(28, 142, 177, 0.24), transparent 32rem),
    var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Yu Gothic UI", Meiryo, sans-serif;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--blue);
  text-underline-offset: 0.2em;
}

a:hover {
  color: #8ce7fb;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: rgba(2, 11, 27, 0.82);
  backdrop-filter: blur(18px);
}

.header-inner,
.page,
.site-footer {
  width: min(960px, calc(100% - 40px));
  margin-inline: auto;
}

.header-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  font-size: 1.08rem;
  font-weight: 760;
  letter-spacing: 0.01em;
  text-decoration: none;
}

.brand-mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(65, 200, 236, 0.5);
  border-radius: 11px;
  color: var(--blue);
  background: linear-gradient(145deg, rgba(65, 200, 236, 0.18), rgba(65, 200, 236, 0.03));
  box-shadow: inset 0 0 18px rgba(65, 200, 236, 0.08);
}

.language-switch {
  display: inline-flex;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(8, 25, 44, 0.86);
}

.language-switch button {
  min-width: 50px;
  padding: 7px 12px;
  border: 0;
  border-radius: 999px;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-size: 0.82rem;
  font-weight: 700;
  cursor: pointer;
}

.language-switch button[aria-pressed="true"] {
  color: #00131d;
  background: var(--blue);
}

.page {
  padding: 86px 0 64px;
}

.hero {
  max-width: 760px;
  margin-bottom: 50px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--blue);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  line-height: 1.25;
  letter-spacing: -0.025em;
}

h1 {
  margin: 0;
  font-size: clamp(2.45rem, 7vw, 4.8rem);
  font-weight: 820;
}

.lead {
  margin: 22px 0 0;
  color: #cad6e1;
  font-size: clamp(1.05rem, 2.2vw, 1.28rem);
  line-height: 1.8;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.card,
.document {
  border: 1px solid var(--line);
  border-radius: 24px;
  background: linear-gradient(145deg, rgba(14, 38, 64, 0.86), rgba(5, 19, 35, 0.88));
  box-shadow: var(--shadow);
}

.card {
  padding: 28px;
}

.card h2 {
  margin: 0 0 9px;
  font-size: 1.28rem;
}

.card p {
  margin: 0;
  color: var(--muted);
}

.card-link {
  position: relative;
  display: block;
  color: inherit;
  text-decoration: none;
  transition: transform 160ms ease, border-color 160ms ease;
}

.card-link:hover {
  transform: translateY(-3px);
  border-color: rgba(65, 200, 236, 0.55);
  color: inherit;
}

.card-link::after {
  content: "→";
  position: absolute;
  top: 26px;
  right: 28px;
  color: var(--blue);
  font-size: 1.35rem;
}

.document {
  padding: clamp(26px, 5vw, 54px);
}

.document section + section {
  padding-top: 30px;
  margin-top: 30px;
  border-top: 1px solid var(--line);
}

.document h2 {
  margin: 0 0 12px;
  font-size: clamp(1.3rem, 3vw, 1.65rem);
}

.document h3 {
  margin: 24px 0 8px;
  font-size: 1.05rem;
}

.document p,
.document li {
  color: #c7d3df;
}

.document p {
  margin: 0 0 14px;
}

.document ul,
.document ol {
  margin: 10px 0 0;
  padding-left: 1.4em;
}

.document li + li {
  margin-top: 8px;
}

.meta {
  margin-top: 18px;
  color: var(--muted);
  font-size: 0.9rem;
}

.notice {
  margin: 24px 0;
  padding: 18px 20px;
  border-left: 3px solid var(--blue);
  border-radius: 8px 16px 16px 8px;
  background: rgba(65, 200, 236, 0.08);
  color: #d7e8f2;
}

.contact-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  margin-top: 8px;
  padding: 0 22px;
  border-radius: 999px;
  color: #00131d;
  background: var(--blue);
  font-weight: 800;
  text-decoration: none;
}

.contact-button:hover {
  color: #00131d;
  background: #85e5f8;
}

.site-footer {
  padding: 28px 0 46px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.86rem;
}

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

.footer-nav {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

[data-lang-panel] {
  display: none;
}

body[data-language="ja"] [data-lang-panel="ja"],
body[data-language="en"] [data-lang-panel="en"] {
  display: block;
}

@media (max-width: 680px) {
  .header-inner,
  .page,
  .site-footer {
    width: min(100% - 28px, 960px);
  }

  .page {
    padding-top: 58px;
  }

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

  .brand-mark {
    width: 31px;
    height: 31px;
  }
}

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