:root {
  --brand: #a5242f;
  --brand-dark: #751720;
  --ink: #191b1f;
  --muted: #64686f;
  --paper: #f7f4ef;
  --white: #ffffff;
  --teal: #2f6f6a;
  --gold: #d4a54a;
  --line: #ded9d0;
  --soft-red: #f3e5e3;
  --soft-teal: #e2efed;
  --shadow: 0 18px 46px rgba(35, 31, 27, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0;
}

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

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

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 1000;
  padding: 8px 12px;
  color: var(--white);
  background: var(--ink);
  transform: translateY(-150%);
}

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

.container {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid rgba(222, 217, 208, 0.88);
  background: rgba(247, 244, 239, 0.96);
  backdrop-filter: blur(14px);
}

.nav-wrap {
  display: flex;
  min-height: 72px;
  align-items: center;
  gap: 26px;
}

.brand {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
  gap: 10px;
  font-size: 21px;
  font-weight: 800;
}

.brand img {
  width: 38px;
  height: 38px;
  border-radius: 7px;
}

.site-nav {
  display: flex;
  align-items: center;
  margin-left: auto;
  gap: 4px;
}

.site-nav a {
  padding: 8px 12px;
  border-bottom: 2px solid transparent;
  color: #3e4248;
  font-size: 14px;
  font-weight: 650;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--brand);
  border-bottom-color: var(--brand);
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  margin-left: auto;
  padding: 10px;
  border: 1px solid var(--line);
  background: transparent;
  cursor: pointer;
}

.menu-toggle span {
  display: block;
  height: 2px;
  margin: 4px 0;
  background: var(--ink);
}

.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  border: 1px solid var(--brand);
  border-radius: 4px;
  color: var(--white);
  background: var(--brand);
  font-weight: 750;
  transition: transform 160ms ease, background 160ms ease;
}

.button:hover {
  background: var(--brand-dark);
  transform: translateY(-2px);
}

.button-light {
  color: var(--ink);
  border-color: var(--line);
  background: var(--white);
}

.button-light:hover {
  color: var(--brand);
  background: var(--white);
}

.nav-download {
  flex: 0 0 auto;
  min-height: 40px;
  padding: 7px 16px;
  font-size: 14px;
}

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

.hero-grid {
  display: grid;
  min-height: 670px;
  grid-template-columns: minmax(0, 1fr) minmax(420px, 0.9fr);
  align-items: center;
  gap: 70px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 16px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0;
}

.eyebrow::before {
  width: 34px;
  height: 2px;
  background: var(--brand);
  content: "";
}

h1,
h2,
h3 {
  margin-top: 0;
  line-height: 1.22;
  letter-spacing: 0;
}

h1 {
  max-width: 720px;
  margin-bottom: 22px;
  font-size: 58px;
}

.hero-copy > p {
  max-width: 650px;
  margin: 0 0 28px;
  color: #4b4f55;
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.fact-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  margin: 28px 0 0;
  padding: 0;
  color: #555960;
  font-size: 14px;
  list-style: none;
}

.fact-list li::before {
  margin-right: 7px;
  color: var(--teal);
  content: "●";
}

.hero-visual {
  position: relative;
  display: flex;
  min-height: 560px;
  align-items: center;
  justify-content: center;
  gap: 18px;
}

.hero-visual::before {
  position: absolute;
  inset: 50% auto auto 50%;
  width: 410px;
  height: 410px;
  border: 1px solid #c9c2b7;
  border-radius: 50%;
  transform: translate(-50%, -50%);
  content: "";
}

.hero-visual img {
  position: relative;
  width: min(44%, 208px);
  max-width: 400px;
  margin: auto 0;
  border: 8px solid #202226;
  border-radius: 24px;
  box-shadow: var(--shadow);
}

.section {
  padding: 90px 0;
}

.section-ink {
  color: var(--white);
  background: var(--ink);
}

.section-white {
  background: var(--white);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 36px;
}

.section-head h2,
.section > .container > h2 {
  margin-bottom: 0;
  font-size: 38px;
}

.section-index {
  flex: 0 0 auto;
  color: var(--brand);
  font-family: Consolas, Monaco, monospace;
  font-size: 13px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.feature {
  min-height: 220px;
  padding: 30px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.feature-number {
  display: block;
  margin-bottom: 36px;
  color: var(--brand);
  font-family: Consolas, Monaco, monospace;
  font-size: 13px;
}

.feature h3 {
  margin-bottom: 10px;
  font-size: 21px;
}

.feature p {
  margin: 0;
  color: var(--muted);
}

.screen-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 22px;
}

.screen-item {
  margin: 0;
}

.screen-frame {
  padding: 10px;
  border: 1px solid #42454a;
  background: #26292d;
}

.screen-frame img {
  width: 100%;
  max-width: 400px;
  margin: 0 auto;
}

.screen-item figcaption {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  padding-top: 14px;
  color: #c7c8ca;
  font-size: 14px;
}

.screen-item figcaption b {
  color: var(--gold);
  font-family: Consolas, Monaco, monospace;
}

.path-grid {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 70px;
}

.path-copy h2 {
  margin-bottom: 20px;
  font-size: 38px;
}

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

.path-steps {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.path-steps li {
  display: grid;
  grid-template-columns: 62px 1fr;
  gap: 18px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.path-steps span {
  color: var(--brand);
  font-family: Consolas, Monaco, monospace;
  font-weight: 800;
}

.path-steps strong {
  display: block;
  margin-bottom: 4px;
}

.path-steps p {
  margin: 0;
  color: var(--muted);
}

.signal-band {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--line);
  background: var(--white);
}

.signal {
  padding: 26px;
  border-right: 1px solid var(--line);
}

.signal:last-child {
  border-right: 0;
}

.signal strong {
  display: block;
  color: var(--brand);
  font-size: 28px;
}

.signal span {
  color: var(--muted);
  font-size: 14px;
}

.quote-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
  margin-top: 28px;
}

.quote {
  margin: 0;
  padding: 26px;
  border-left: 3px solid var(--teal);
  background: var(--white);
}

.quote p {
  margin: 0 0 15px;
}

.quote cite {
  color: var(--muted);
  font-size: 13px;
  font-style: normal;
}

.faq-list {
  border-top: 1px solid var(--line);
}

.faq-list details {
  border-bottom: 1px solid var(--line);
}

.faq-list summary {
  position: relative;
  padding: 22px 48px 22px 0;
  font-size: 18px;
  font-weight: 750;
  cursor: pointer;
  list-style: none;
}

.faq-list summary::-webkit-details-marker {
  display: none;
}

.faq-list summary::after {
  position: absolute;
  top: 21px;
  right: 4px;
  color: var(--brand);
  content: "+";
  font-size: 24px;
}

.faq-list details[open] summary::after {
  content: "−";
}

.faq-list details p {
  max-width: 850px;
  margin: -6px 0 22px;
  color: var(--muted);
}

.download-band {
  padding: 66px 0;
  color: var(--white);
  background: var(--brand);
}

.download-band .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}

.download-band h2 {
  margin: 0 0 8px;
  font-size: 34px;
}

.download-band p {
  margin: 0;
  color: #f1d8d5;
}

.download-band .button {
  color: var(--brand);
  border-color: var(--white);
  background: var(--white);
}

.site-footer {
  padding: 48px 0 28px;
  color: #b9bbbe;
  background: #111316;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 50px;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--white);
  font-size: 20px;
  font-weight: 800;
}

.footer-brand img {
  width: 36px;
  height: 36px;
  border-radius: 7px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  align-content: start;
  justify-content: flex-end;
  gap: 10px 22px;
}

.footer-links a:hover {
  color: var(--white);
}

.disclaimer {
  margin: 28px 0 0;
  padding-top: 22px;
  border-top: 1px solid #303338;
  font-size: 13px;
}

.copyright {
  margin: 8px 0 0;
  font-size: 13px;
}

.page-hero {
  padding: 92px 0 70px;
  border-bottom: 1px solid var(--line);
}

.page-hero h1 {
  margin-bottom: 18px;
  font-size: 50px;
}

.page-hero p {
  max-width: 780px;
  margin: 0;
  color: var(--muted);
  font-size: 18px;
}

.breadcrumb {
  margin-bottom: 24px;
  color: var(--muted);
  font-size: 13px;
}

.breadcrumb a {
  color: var(--brand);
}

.content-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  align-items: start;
  gap: 60px;
}

.article-section {
  padding: 38px 0;
  border-bottom: 1px solid var(--line);
}

.article-section:first-child {
  padding-top: 0;
}

.article-section h2 {
  margin-bottom: 18px;
  font-size: 29px;
}

.article-section h3 {
  margin: 24px 0 8px;
  font-size: 20px;
}

.article-section p {
  margin: 0 0 14px;
  color: #4e5258;
}

.article-section ul,
.article-section ol {
  padding-left: 22px;
  color: #4e5258;
}

.article-section li {
  margin-bottom: 10px;
}

.step {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 20px;
  padding: 26px 0;
  border-top: 1px solid var(--line);
}

.step-no {
  display: grid;
  width: 48px;
  height: 48px;
  place-items: center;
  color: var(--white);
  background: var(--brand);
  font-family: Consolas, Monaco, monospace;
  font-weight: 800;
}

.step h3 {
  margin: 0 0 8px;
}

.step p {
  margin: 0;
}

.inline-screen {
  width: min(100%, 330px);
  max-width: 400px;
  margin: 20px auto 0;
  padding: 9px;
  border: 1px solid var(--line);
  background: var(--white);
  box-shadow: var(--shadow);
}

.note {
  margin: 20px 0;
  padding: 18px 20px;
  border-left: 4px solid var(--gold);
  background: #fbf4df;
}

.note p {
  margin: 0;
  color: #5b4b2b;
}

.side-nav {
  position: sticky;
  top: 100px;
  padding: 22px;
  border: 1px solid var(--line);
  background: var(--white);
}

.side-nav strong {
  display: block;
  margin-bottom: 12px;
}

.side-nav a {
  display: block;
  padding: 8px 0;
  color: var(--muted);
  border-bottom: 1px solid #efebe5;
  font-size: 14px;
}

.side-nav a:hover {
  color: var(--brand);
}

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

.related a {
  padding: 24px;
  border: 1px solid var(--line);
  background: var(--white);
}

.related a:hover {
  border-color: var(--brand);
}

.related strong {
  display: block;
  margin-bottom: 5px;
  color: var(--brand);
}

.related span {
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 960px) {
  .site-nav {
    position: absolute;
    top: 72px;
    right: 20px;
    left: 20px;
    display: none;
    padding: 14px;
    border: 1px solid var(--line);
    background: var(--white);
    box-shadow: var(--shadow);
  }

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

  .site-nav a {
    padding: 10px 12px;
  }

  .menu-toggle {
    display: block;
  }

  .hero-grid {
    min-height: auto;
    padding: 70px 0 56px;
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-visual {
    min-height: 480px;
  }

  .hero-visual img {
    width: min(42%, 210px);
  }

  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .screen-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .path-grid,
  .content-layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .side-nav {
    position: static;
    order: -1;
  }

  .signal-band {
    grid-template-columns: repeat(2, 1fr);
  }

  .signal:nth-child(2) {
    border-right: 0;
  }

  .signal:nth-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }
}

@media (max-width: 680px) {
  .container {
    width: min(100% - 28px, 1160px);
  }

  .nav-download {
    display: none;
  }

  h1,
  .page-hero h1 {
    font-size: 38px;
  }

  .hero-grid {
    padding: 40px 0 24px;
    gap: 20px;
  }

  .hero-copy > p,
  .page-hero p {
    font-size: 16px;
  }

  .hero-copy > p {
    margin-bottom: 18px;
  }

  .fact-list {
    margin-top: 16px;
  }

  .hero-visual {
    min-height: 190px;
    gap: 10px;
  }

  .hero-visual::before {
    width: 180px;
    height: 180px;
  }

  .hero-visual img {
    width: min(32%, 110px);
    border-width: 5px;
    border-radius: 16px;
  }

  .section {
    padding: 64px 0;
  }

  .section-head {
    align-items: start;
    flex-direction: column;
  }

  .section-head h2,
  .section > .container > h2,
  .path-copy h2 {
    font-size: 30px;
  }

  .feature-grid,
  .screen-grid,
  .quote-grid,
  .related {
    grid-template-columns: 1fr;
  }

  .feature {
    min-height: 0;
  }

  .signal-band {
    grid-template-columns: 1fr;
  }

  .signal,
  .signal:nth-child(2) {
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .download-band .container,
  .footer-grid {
    align-items: start;
    flex-direction: column;
    grid-template-columns: 1fr;
  }

  .footer-links {
    justify-content: flex-start;
  }

  .step {
    grid-template-columns: 44px 1fr;
    gap: 14px;
  }

  .step-no {
    width: 42px;
    height: 42px;
  }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}