:root {
  color-scheme: light;
  --ink: #142136;
  --muted: #5d687b;
  --line: #d8e0e8;
  --surface: #ffffff;
  --surface-soft: #f6f8fb;
  --blue: #175f91;
  --blue-dark: #104a72;
  --green: #2f6d45;
  --green-soft: #edf7f0;
  --gold-soft: #fff7dd;
  --shadow: 0 18px 48px rgb(20 33 54 / 8%);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  overflow-x: hidden;
  color: var(--ink);
  background: linear-gradient(180deg, #f2f7f7 0, #f6f8fb 48rem, #f8fafc 100%);
  font-size: 1rem;
  line-height: 1.65;
}

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

a:hover {
  color: var(--blue-dark);
}

a:focus-visible,
summary:focus-visible {
  border-radius: 0.35rem;
  outline: 3px solid var(--blue);
  outline-offset: 3px;
}

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

.skip-link {
  position: fixed;
  z-index: 10;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.7rem 1rem;
  border-radius: 0.6rem;
  color: #fff;
  background: var(--ink);
  transform: translateY(-180%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header,
.page-section,
.site-footer {
  width: min(70rem, calc(100% - 2rem));
  margin-inline: auto;
}

.site-header {
  padding-top: 1rem;
}

.site-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 3.25rem;
}

.brand {
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 0.35rem 1rem;
}

.nav-links a {
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  font-weight: 650;
  text-decoration: none;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(20rem, 0.92fr);
  grid-template-areas:
    "eyebrow visual"
    "title visual"
    "lead visual"
    "actions visual"
    "version visual";
  column-gap: clamp(1.25rem, 4vw, 3.5rem);
  row-gap: 0;
  align-items: start;
  padding-block: clamp(3.5rem, 8vw, 6rem) clamp(3.5rem, 7vw, 5.5rem);
}

.hero > .eyebrow {
  grid-area: eyebrow;
}

.hero > h1 {
  grid-area: title;
}

.hero > .lead {
  grid-area: lead;
}

.hero > .actions {
  grid-area: actions;
}

.hero > .version-note {
  grid-area: version;
}

.eyebrow {
  margin: 0 0 0.75rem;
  color: var(--green);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  line-height: 1.12;
  letter-spacing: -0.035em;
}

html[lang="zh-CN"] h1,
html[lang="zh-CN"] h2,
html[lang="zh-CN"] h3 {
  letter-spacing: -0.015em;
}

h1 {
  max-width: 14ch;
  margin-bottom: 1.25rem;
  font-size: clamp(2.35rem, 4.8vw, 4rem);
}

h2 {
  max-width: 19ch;
  margin-bottom: 1rem;
  font-size: clamp(1.85rem, 3.3vw, 2.75rem);
}

@media (min-width: 40rem) {
  html[lang="zh-CN"] h2 {
    max-width: none;
    white-space: nowrap;
  }
}

h3 {
  margin-bottom: 0.55rem;
  font-size: 1.15rem;
}

.lead,
.section-intro {
  max-width: 47rem;
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.2rem);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.75rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0.65rem 1rem;
  border: 1px solid var(--ink);
  border-radius: 0.7rem;
  color: #fff;
  background: var(--ink);
  font-weight: 750;
  text-decoration: none;
}

.button:hover {
  color: #fff;
  background: #263851;
}

.button-secondary {
  color: var(--ink);
  background: transparent;
}

.button-secondary:hover {
  color: var(--ink);
  background: #fff;
}

.version-note {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.hero-visual {
  grid-area: visual;
  align-self: center;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: #fbfaf5;
  box-shadow: var(--shadow);
}

.hero-visual img {
  width: 100%;
  height: auto;
}

.page-section {
  padding-block: clamp(3.5rem, 8vw, 6rem);
  border-top: 1px solid var(--line);
}

.media-frame {
  margin: 2rem 0 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.media-frame img {
  width: 100%;
  height: auto;
}

.media-frame figcaption {
  padding: 0.9rem 1rem 1rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.evidence-note {
  margin-top: 1rem;
  padding: 1rem 1.1rem;
  border-left: 4px solid #b48311;
  border-radius: 0 0.65rem 0.65rem 0;
  background: var(--gold-soft);
}

.evidence-note p {
  margin: 0;
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 1.25rem 0 0;
  padding: 0;
  list-style: none;
}

.steps li,
.boundary-card {
  padding: 1.25rem;
  border: 1px solid var(--line);
  border-radius: 0.9rem;
  background: var(--surface);
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  margin-bottom: 1rem;
  border-radius: 50%;
  color: var(--blue-dark);
  background: #eaf3fa;
  font-size: 0.82rem;
  font-weight: 850;
}

.steps p,
.boundary-card p,
.boundary-card li {
  color: var(--muted);
}

.steps p {
  margin-bottom: 0;
}

.lifecycle-note {
  margin: 1rem 0 0;
  color: var(--muted);
}

.start-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(18rem, 0.95fr);
  gap: 1rem;
  align-items: start;
  margin-top: 2rem;
}

.command-card,
.boundary-card {
  min-width: 0;
}

.start-grid > * {
  min-width: 0;
}

.command-card {
  overflow: hidden;
  border-radius: 0.9rem;
  color: #eff5fb;
  background: #162235;
}

.command-card h3 {
  margin: 0;
  padding: 1.15rem 1.25rem 0;
  color: #fff;
}

pre {
  margin: 0;
  padding: 1rem 1.25rem 1.25rem;
  overflow-x: auto;
  font: 0.9rem/1.75 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  scrollbar-width: thin;
}

code {
  font: inherit;
}

.prompt {
  margin: 1rem 0 0;
  color: var(--muted);
}

.boundary-card ul {
  margin: 0;
  padding-left: 1.2rem;
}

.boundary-card li + li {
  margin-top: 0.55rem;
}

.quick-answers {
  margin-top: 1.75rem;
}

details {
  margin-top: 0.65rem;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: var(--surface);
}

summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 2.75rem;
  padding: 0.85rem 1rem;
  cursor: pointer;
  font-weight: 750;
  list-style: none;
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  content: "+";
  flex: 0 0 auto;
  color: var(--blue);
  font-size: 1.4rem;
  font-weight: 500;
  line-height: 1;
}

details[open] summary {
  border-bottom: 1px solid var(--line);
  background: #fbfcfd;
}

details[open] summary::after {
  content: "−";
}

details p {
  max-width: 48rem;
  margin: 0;
  padding: 0.9rem 1rem 1rem;
  color: var(--muted);
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  padding-block: 2rem 3rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.92rem;
}

.site-footer p {
  margin: 0;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
}

@media (max-width: 48rem) {
  .site-header,
  .page-section,
  .site-footer {
    width: min(100% - 1.25rem, 70rem);
  }

  .site-nav {
    align-items: flex-start;
  }

  .nav-links {
    gap: 0.15rem 0.75rem;
  }

  .hero,
  .start-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    grid-template-areas:
      "eyebrow"
      "title"
      "lead"
      "visual"
      "actions"
      "version";
    padding-top: 3.5rem;
  }

  .hero-visual {
    margin-top: 1.75rem;
  }

  .hero > .actions {
    margin-top: 1.25rem;
  }

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

  .media-frame {
    border-radius: 0.75rem;
  }

  .lifecycle-frame {
    overflow-x: auto;
    overscroll-behavior-inline: contain;
  }

  .lifecycle-frame img {
    width: 60rem;
    max-width: none;
  }
}

@media (max-width: 30rem) {
  .site-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
  }

  .nav-links {
    width: 100%;
    justify-content: flex-start;
  }

  .actions {
    display: grid;
  }

  .button {
    width: 100%;
  }
}

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