:root {
  --bg: #f4efe6;
  --bg-alt: #ebe4d6;
  --ink: #1b2430;
  --muted: #445060;
  --line: #c9bfae;
  --panel: #fffdf8;
  --accent: #1f4d3a;
  --accent-2: #c45c26;
  --focus: #0b57d0;
  --shadow: 0 18px 40px rgba(27, 36, 48, 0.08);
  --radius: 18px;
  --max: 1080px;
  --font: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(196, 92, 38, 0.08), transparent 28%),
    linear-gradient(180deg, #f7f3ea 0%, var(--bg) 40%);
  line-height: 1.7;
  min-height: 100vh;
}

img,
svg {
  max-width: 100%;
}

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

a:hover {
  color: #16382b;
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 20;
  background: var(--ink);
  color: #fff;
  padding: 0.6rem 1rem;
  border-radius: 8px;
}

.skip-link:focus {
  top: 1rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.wrap {
  width: min(calc(100% - 2rem), var(--max));
  margin-inline: auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(244, 239, 230, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 4.25rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: inherit;
}

.brand-mark {
  width: 2.1rem;
  height: 2.1rem;
  border-radius: 50%;
  background:
    conic-gradient(from 210deg, var(--accent), #7ea48d, var(--accent-2), var(--accent));
  box-shadow: inset 0 0 0 4px var(--panel);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-text strong {
  font-size: 1.05rem;
}

.brand-text span {
  color: var(--muted);
  font-size: 0.78rem;
}

.nav-toggle {
  display: none;
  width: 2.6rem;
  height: 2.6rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  cursor: pointer;
}

.nav-toggle-bar,
.nav-toggle-bar::before,
.nav-toggle-bar::after {
  display: block;
  width: 1.1rem;
  height: 2px;
  background: var(--ink);
  margin: 0 auto;
  position: relative;
}

.nav-toggle-bar::before,
.nav-toggle-bar::after {
  content: "";
  position: absolute;
  left: 0;
}

.nav-toggle-bar::before {
  top: -6px;
}

.nav-toggle-bar::after {
  top: 6px;
}

.site-nav ul {
  display: flex;
  gap: 0.35rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-nav a {
  display: inline-flex;
  padding: 0.45rem 0.8rem;
  text-decoration: none;
  color: var(--ink);
  border-radius: 999px;
}

.site-nav a:hover,
.site-nav a[aria-current="true"] {
  background: #e4ddd0;
}

.hero {
  padding: 4.5rem 0 3.5rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.9fr;
  gap: 1.5rem;
  align-items: stretch;
}

.eyebrow {
  margin: 0 0 0.6rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-size: 0.75rem;
  color: var(--accent-2);
  font-weight: 700;
}

h1,
h2,
h3,
h4 {
  line-height: 1.25;
  margin: 0 0 0.8rem;
}

h1 {
  font-size: clamp(2rem, 4vw, 3.1rem);
  letter-spacing: -0.03em;
}

.lede {
  font-size: 1.12rem;
  color: var(--muted);
  max-width: 40rem;
}

.notice {
  max-width: 42rem;
  padding: 0.9rem 1rem;
  border-left: 4px solid var(--accent-2);
  background: #fff7ee;
  color: #5a3016;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.4rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.55rem 1.1rem;
  border-radius: 999px;
  text-decoration: none;
  border: 1px solid transparent;
  font: inherit;
  cursor: pointer;
}

.btn-primary {
  background: var(--accent);
  color: #f7fff9;
}

.btn-primary:hover {
  background: #16382b;
  color: #fff;
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}

.btn-ghost:hover {
  background: #efe8db;
}

.hero-panel,
.card,
.lab-note {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero-panel {
  padding: 1.4rem 1.5rem;
}

.panel-title {
  font-size: 1rem;
  margin-bottom: 1rem;
}

.fact-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.fact-list li {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem 0;
  border-top: 1px solid var(--line);
}

.fact-k {
  color: var(--muted);
}

.section {
  padding: 3.2rem 0;
}

.section-alt {
  background: var(--bg-alt);
  border-block: 1px solid var(--line);
}

.section-head {
  max-width: 42rem;
  margin-bottom: 1.8rem;
}

.card-grid,
.io-grid {
  display: grid;
  gap: 1rem;
}

.card-grid {
  grid-template-columns: repeat(3, 1fr);
}

.card,
.io {
  padding: 1.2rem 1.25rem;
}

.card h3 {
  font-size: 1.05rem;
}

.lab-note {
  padding: 1.4rem;
}

.lab-note-top {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.7rem;
  margin-bottom: 0.8rem;
}

.badge {
  margin: 0;
  display: inline-flex;
  padding: 0.22rem 0.7rem;
  border-radius: 999px;
  background: #1f4d3a;
  color: #f4fff8;
  font-size: 0.82rem;
  font-weight: 700;
}

.meta {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.spec {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.8rem;
  margin: 1.2rem 0;
}

.spec div {
  background: #f7f1e6;
  border-radius: 12px;
  padding: 0.8rem;
}

dt {
  color: var(--muted);
  font-size: 0.82rem;
}

dd {
  margin: 0.2rem 0 0;
  font-weight: 600;
}

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

.io {
  background: #1b2430;
  color: #eef3ea;
  border-radius: 14px;
}

.io h4 {
  margin-bottom: 0.6rem;
  color: #d7c4a5;
  font-size: 0.92rem;
}

pre {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: "Sarasa Mono SC", "Noto Sans Mono CJK SC", ui-monospace, monospace;
  font-size: 0.92rem;
  line-height: 1.65;
}

.lab-note-foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  margin-top: 1.1rem;
}

.copy-status {
  min-height: 1.4rem;
  color: var(--accent);
  margin: 0.4rem 0 0;
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
}

.steps li {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.2rem 1.3rem;
}

.step-n {
  display: inline-block;
  margin-right: 0.5rem;
  color: var(--accent-2);
  font-variant-numeric: tabular-nums;
}

.site-footer {
  padding: 2rem 0 2.4rem;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.footer-inner p {
  margin: 0.2rem 0;
}

@media (max-width: 860px) {
  .hero-grid,
  .card-grid,
  .io-grid,
  .spec {
    grid-template-columns: 1fr;
  }

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .site-nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 4.25rem;
    background: var(--panel);
    border-bottom: 1px solid var(--line);
    padding: 0.6rem 1rem 1rem;
  }

  .site-nav.is-open {
    display: block;
  }

  .site-nav ul {
    flex-direction: column;
  }

  .hero {
    padding-top: 2.6rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}