:root {
  --ink: #142224;
  --muted: #607174;
  --paper: #f3f1eb;
  --panel: #fbfaf6;
  --line: #d7ddd8;
  --dark: #061012;
  --teal: #58d5cb;
  --gold: #d1a253;
  --serif: "Noto Serif SC", "Songti SC", "STSong", serif;
  --sans: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.9;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

.skip {
  position: fixed;
  left: 18px;
  top: 14px;
  z-index: 20;
  padding: 9px 13px;
  background: #fff;
  color: #061012;
  transform: translateY(-140%);
}

.skip:focus {
  transform: none;
}

.site-head {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  min-height: 72px;
  padding: 0 max(24px, 4vw);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(6, 16, 18, 0.96);
  color: #ecf2ee;
  backdrop-filter: blur(14px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.brand img {
  width: 31px;
  height: 31px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
  color: #b9c7c4;
  font-size: 13px;
}

.site-nav a:hover,
.site-foot a:hover {
  color: #fff;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 100px max(24px, calc((100vw - 1120px) / 2)) 84px;
  background: var(--dark);
  color: #eef3ef;
}

.hero::before {
  position: absolute;
  inset: -40% -15%;
  background:
    radial-gradient(circle at 78% 38%, rgba(88, 213, 203, 0.17), transparent 28%),
    radial-gradient(circle at 20% 85%, rgba(209, 162, 83, 0.12), transparent 24%);
  content: "";
  pointer-events: none;
}

.hero-inner {
  position: relative;
  max-width: 960px;
}

.eyebrow {
  margin: 0 0 24px;
  color: var(--teal);
  font-size: 11px;
  letter-spacing: 0.18em;
}

h1 {
  max-width: 930px;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(45px, 6vw, 76px);
  font-weight: 500;
  line-height: 1.18;
  letter-spacing: -0.045em;
}

.byline {
  margin: 28px 0 0;
  color: #9fadaa;
  font-size: 13px;
}

.answer {
  max-width: 880px;
  margin: 42px 0 0;
  padding-left: 22px;
  border-left: 2px solid var(--gold);
  color: #dfe7e3;
  font-size: 20px;
  line-height: 1.8;
}

.answer p:last-child {
  margin-bottom: 0;
}

.article {
  width: min(100% - 48px, 860px);
  margin: 0 auto;
  padding: 84px 0 112px;
}

.article h2 {
  margin: 80px 0 24px;
  color: #102022;
  font-family: var(--serif);
  font-size: clamp(30px, 4vw, 43px);
  font-weight: 500;
  line-height: 1.35;
  letter-spacing: -0.025em;
}

.article h3 {
  margin: 52px 0 14px;
  color: #183234;
  font-family: var(--serif);
  font-size: 25px;
  font-weight: 600;
  line-height: 1.45;
}

.article p {
  margin: 0 0 20px;
}

.article ul,
.article ol {
  margin: 16px 0 26px;
  padding-left: 1.5em;
}

.article li {
  margin: 8px 0;
  padding-left: 4px;
}

.article pre {
  max-width: 100%;
  margin: 24px 0 34px;
  padding: 20px;
  overflow-x: auto;
  border: 1px solid var(--line);
  background: #f9fbf8;
  color: #294647;
  font-size: 14px;
  line-height: 1.7;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.article code {
  overflow-wrap: anywhere;
  word-break: break-word;
}

.article a:not(.primary-action, .secondary-action) {
  color: #176c68;
  text-decoration: underline;
  text-underline-offset: 3px;
  overflow-wrap: anywhere;
}

.case-figure {
  margin: 48px 0 70px;
  border: 1px solid var(--line);
  background: #fff;
  box-shadow: 0 22px 60px rgba(22, 42, 43, 0.09);
}

.case-figure img {
  width: 100%;
  object-fit: cover;
}

.case-figure.square img {
  aspect-ratio: 1;
}

.case-figure figcaption {
  padding: 15px 18px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.65;
}

.case-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin: 48px 0 70px;
}

.case-grid .case-figure {
  margin: 0;
}

.action-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin: 34px 0 6px;
}

.primary-action,
.secondary-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 22px;
  font-size: 14px;
}

.primary-action {
  background: #173f40;
  color: #fff;
  font-weight: 700;
}

.primary-action::after {
  margin-left: 14px;
  color: var(--teal);
  content: "↗";
}

.secondary-action {
  border: 1px solid #aebcba;
  color: #294647;
}

.direct-fact,
.note {
  margin: 24px 0;
  padding: 24px;
  border-left: 3px solid var(--teal);
  background: #f9fbf8;
  font-size: 18px;
}

.direct-fact code {
  overflow-wrap: anywhere;
  word-break: break-all;
}

.table-wrap {
  max-width: 100%;
  margin: 28px 0 42px;
  overflow-x: auto;
}

.facts,
.content-table {
  width: 100%;
  border-collapse: collapse;
  background: #f9fbf8;
  font-size: 14px;
  line-height: 1.65;
}

.content-table {
  min-width: 680px;
}

.facts th,
.facts td,
.content-table th,
.content-table td {
  padding: 13px 15px;
  border: 1px solid #d4dfda;
  text-align: left;
  vertical-align: top;
}

.facts th,
.content-table th {
  color: #315153;
  font-weight: 700;
}

.facts th {
  width: 150px;
}

.checklist {
  padding: 28px 30px;
  border: 1px solid #cdd8d4;
  background: #e8eeea;
}

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

.checklist ul {
  padding-left: 1.25em;
  list-style: "□  ";
}

.faq {
  margin-top: 86px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

.faq h2 {
  margin-top: 52px;
}

.faq h3 {
  font-family: var(--sans);
  font-size: 19px;
  font-weight: 700;
}

.sources {
  margin-top: 86px;
  padding: 34px;
  border: 1px solid var(--line);
  background: var(--panel);
}

.sources h2 {
  margin-top: 0;
  font-size: 30px;
}

.fact-section {
  margin: 86px -42px 0;
  padding: 58px 42px 46px;
  border: 1px solid #cdd8d4;
  background: #e8eeea;
}

.fact-section > h2 {
  margin-top: 0;
}

.site-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 34px max(24px, 4vw);
  background: var(--dark);
  color: #97a6a3;
  font-size: 12px;
}

.site-foot nav {
  display: flex;
  flex-wrap: wrap;
  gap: 22px;
}

:focus-visible {
  outline: 2px solid var(--teal);
  outline-offset: 4px;
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
    line-height: 1.84;
  }

  .site-head {
    min-height: 64px;
    padding: 0 18px;
  }

  .site-nav {
    gap: 16px;
    font-size: 12px;
  }

  .hero {
    padding: 72px 24px 62px;
  }

  h1 {
    font-size: 42px;
  }

  .answer {
    margin-top: 34px;
    font-size: 18px;
  }

  .article {
    width: min(100% - 36px, 860px);
    padding: 58px 0 88px;
  }

  .article h2 {
    margin-top: 62px;
    font-size: 31px;
  }

  .article h3 {
    margin-top: 40px;
    font-size: 22px;
  }

  .case-figure {
    margin: 38px 0 52px;
  }

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

  .fact-section {
    margin: 68px 0 0;
    padding: 40px 18px 30px;
  }

  .table-wrap,
  .fact-section {
    overflow-x: auto;
  }

  .facts {
    min-width: 620px;
  }

  .action-row {
    align-items: stretch;
    flex-direction: column;
  }

  .primary-action,
  .secondary-action {
    width: 100%;
  }

  .sources,
  .checklist {
    padding: 24px 18px;
  }

  .site-foot {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (max-width: 430px) {
  h1 {
    font-size: 36px;
  }

  .site-nav a:first-child {
    display: none;
  }

  .article {
    width: calc(100% - 32px);
  }
}

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