:root {
  color-scheme: dark;
  --bg: #04060b;
  --panel: #0c121d;
  --panel-soft: #111b2a;
  --text: #f7f8fb;
  --muted: #a7b1c2;
  --line: #25334a;
  --blue: #3289ff;
  --cyan: #38d9e6;
  --green: #35e0a1;
  --gold: #ffc24d;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(circle at 80% 0%, rgba(53, 224, 161, 0.1), transparent 28rem),
    radial-gradient(circle at 10% 25%, rgba(50, 137, 255, 0.13), transparent 30rem),
    var(--bg);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

a {
  color: var(--cyan);
}

.shell {
  width: min(960px, calc(100% - 36px));
  margin: 0 auto;
  padding: 72px 0 40px;
}

.hero {
  max-width: 780px;
  padding: 56px;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: linear-gradient(135deg, rgba(17, 27, 42, 0.95), rgba(8, 23, 25, 0.95));
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.28);
}

.eyebrow,
.card-label {
  margin: 0 0 10px;
  color: var(--cyan);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.16em;
}

h1,
h2 {
  line-height: 1.15;
}

h1 {
  margin: 0 0 18px;
  font-size: clamp(2.4rem, 7vw, 4.8rem);
  letter-spacing: -0.045em;
}

h2 {
  margin: 38px 0 12px;
  font-size: 1.45rem;
}

.lead {
  max-width: 650px;
  margin: 0;
  color: var(--muted);
  font-size: 1.1rem;
}

.cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-top: 28px;
}

.card {
  position: relative;
  min-height: 230px;
  padding: 28px;
  color: var(--text);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--panel);
  transition: transform 160ms ease, border-color 160ms ease;
}

.card:hover,
.card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--cyan);
}

.card h2 {
  margin-top: 14px;
}

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

.arrow {
  position: absolute;
  right: 26px;
  bottom: 22px;
  color: var(--green);
  font-size: 1.8rem;
}

.japanese {
  margin-top: 44px;
  padding: 4px 10px;
  color: var(--muted);
}

.document {
  max-width: 800px;
}

.document nav {
  margin-bottom: 48px;
}

.document nav a {
  color: var(--muted);
  text-decoration: none;
}

.document header,
.document section {
  padding: 0 4px;
}

.document header {
  margin-bottom: 44px;
}

.document h1 {
  font-size: clamp(2.4rem, 7vw, 4rem);
}

.document p,
.document li {
  color: #c5ccda;
}

.updated {
  color: var(--gold) !important;
  font-weight: 700;
}

.button {
  display: inline-block;
  margin-top: 26px;
  padding: 13px 18px;
  color: #041014;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--blue), var(--green));
  font-weight: 800;
  text-decoration: none;
}

hr {
  margin: 64px 0;
  border: 0;
  border-top: 1px solid var(--line);
}

footer {
  margin-top: 72px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

footer p {
  margin: 5px 0;
  color: #77849a !important;
  font-size: 0.78rem;
}

@media (max-width: 650px) {
  .shell {
    width: min(100% - 24px, 960px);
    padding-top: 24px;
  }

  .hero {
    padding: 34px 24px;
    border-radius: 20px;
  }

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