:root {
  color-scheme: dark;
  --bg: #05070d;
  --panel: rgba(15, 22, 34, 0.82);
  --line: rgba(231, 238, 247, 0.12);
  --text: #e7eef7;
  --muted: #9aa7b8;
  --primary: #4dd8e8;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 12% 0%, rgba(77, 216, 232, 0.14), transparent 34%),
    radial-gradient(circle at 86% 10%, rgba(143, 182, 255, 0.1), transparent 34%),
    linear-gradient(180deg, #060913 0%, #05070d 60%, #03050a 100%);
  color: var(--text);
  font-family: Inter, "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.75;
}

a {
  color: inherit;
}

.page {
  margin: 0 auto;
  max-width: 1040px;
  padding: 48px 20px 72px;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: space-between;
  margin-bottom: 56px;
}

.nav a,
.chip {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.04);
  color: var(--muted);
  font-size: 13px;
  letter-spacing: 0.04em;
  padding: 8px 12px;
  text-decoration: none;
}

.hero {
  border-bottom: 1px solid var(--line);
  padding-bottom: 38px;
}

.eyebrow {
  color: var(--primary);
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1 {
  font-size: clamp(36px, 7vw, 72px);
  letter-spacing: 0;
  line-height: 1.05;
  margin: 16px 0 20px;
}

.lead {
  color: #cbd6e4;
  font-size: 18px;
  max-width: 820px;
}

.grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  margin-top: 32px;
}

.card,
.qa,
.section {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.28);
}

.card {
  padding: 20px;
}

.card h2,
.qa h2,
.section h2 {
  font-size: 20px;
  margin: 0 0 10px;
}

.card p,
.qa p,
.section p,
li {
  color: var(--muted);
}

.answer {
  border-left: 3px solid var(--primary);
  color: #d7e4f4;
  font-size: 18px;
  margin-top: 24px;
  max-width: 900px;
  padding-left: 18px;
}

.toc {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.toc a {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.035);
  color: #cbd6e4;
  font-size: 14px;
  padding: 8px 12px;
  text-decoration: none;
}

.steps {
  counter-reset: step;
  display: grid;
  gap: 14px;
  margin-top: 18px;
}

.step {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.03);
  padding: 18px 18px 18px 58px;
  position: relative;
}

.step::before {
  align-items: center;
  background: rgba(77, 216, 232, 0.12);
  border: 1px solid rgba(77, 216, 232, 0.35);
  border-radius: 8px;
  color: var(--primary);
  content: counter(step, decimal-leading-zero);
  counter-increment: step;
  display: flex;
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 12px;
  font-weight: 700;
  height: 30px;
  justify-content: center;
  left: 16px;
  position: absolute;
  top: 18px;
  width: 30px;
}

.step h3 {
  font-size: 17px;
  margin: 0 0 6px;
}

.note {
  border: 1px solid rgba(77, 216, 232, 0.24);
  border-radius: 8px;
  background: rgba(77, 216, 232, 0.06);
  color: #cfeef4;
  margin-top: 20px;
  padding: 16px;
}

.table {
  border: 1px solid var(--line);
  border-radius: 8px;
  margin-top: 18px;
  overflow: hidden;
}

.row {
  display: grid;
  gap: 0;
  grid-template-columns: 0.8fr 1.2fr 1fr;
}

.row > div {
  border-bottom: 1px solid var(--line);
  border-right: 1px solid var(--line);
  color: var(--muted);
  padding: 13px 14px;
}

.row > div:last-child {
  border-right: 0;
}

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

.row.head > div {
  background: rgba(255, 255, 255, 0.045);
  color: #e7eef7;
  font-weight: 700;
}

.section,
.qa {
  margin-top: 24px;
  padding: 24px;
}

.qa h3 {
  font-size: 17px;
  margin: 22px 0 8px;
}

.qa h3:first-child {
  margin-top: 0;
}

.footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
  margin-top: 48px;
  padding-top: 24px;
}

@media (max-width: 640px) {
  .page {
    padding-top: 28px;
  }

  .nav {
    margin-bottom: 36px;
  }

  .lead {
    font-size: 16px;
  }

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

  .row > div {
    border-right: 0;
  }
}