:root {
  --ink: #151a17;
  --paper: #f7f7f2;
  --white: #ffffff;
  --green: #58d276;
  --green-dark: #21894a;
  --yellow: #f4d84a;
  --coral: #ff6b5e;
  --blue: #4387f4;
  --muted: #677069;
  --line: #d9ddd8;
  --shadow: 7px 7px 0 var(--ink);
  --max: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.75;
}

body.menu-open {
  overflow: hidden;
}

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

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

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

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

.skip-link {
  position: fixed;
  top: -80px;
  left: 16px;
  z-index: 1000;
  padding: 10px 16px;
  background: var(--yellow);
  border: 2px solid var(--ink);
  font-weight: 800;
}

.skip-link:focus {
  top: 12px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 74px;
  background: rgba(247, 247, 242, 0.97);
  border-bottom: 2px solid var(--ink);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 74px;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: max-content;
  font-size: 22px;
  font-weight: 900;
}

.brand img {
  width: 44px;
  height: 44px;
  border-radius: 8px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  font-weight: 700;
}

.site-nav a:not(.download-btn) {
  position: relative;
  padding: 22px 0 18px;
}

.site-nav a:not(.download-btn)::after {
  position: absolute;
  right: 0;
  bottom: 13px;
  left: 0;
  height: 4px;
  background: var(--green);
  content: "";
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 180ms ease;
}

.site-nav a:hover::after,
.site-nav a.active::after {
  transform: scaleX(1);
}

.download-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 11px 22px;
  color: var(--ink);
  background: var(--yellow);
  border: 2px solid var(--ink);
  border-radius: 6px;
  box-shadow: 4px 4px 0 var(--ink);
  font-size: 16px;
  font-weight: 900;
  line-height: 1;
  transition: transform 160ms ease, box-shadow 160ms ease;
}

.download-btn:hover,
.download-btn:focus-visible {
  box-shadow: 2px 2px 0 var(--ink);
  transform: translate(2px, 2px);
}

.download-btn.dark {
  color: var(--white);
  background: var(--ink);
  border-color: var(--white);
  box-shadow: 4px 4px 0 var(--green);
}

.menu-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 8px;
  color: var(--ink);
  background: var(--white);
  border: 2px solid var(--ink);
  border-radius: 6px;
  font-size: 25px;
  line-height: 1;
  cursor: pointer;
}

.hero {
  position: relative;
  min-height: min(700px, calc(100vh - 74px));
  overflow: hidden;
  color: var(--white);
  background: var(--ink);
  border-bottom: 8px solid var(--yellow);
}

.hero::before {
  position: absolute;
  top: 36px;
  right: 4vw;
  width: min(46vw, 540px);
  height: calc(100% - 72px);
  border: 2px solid rgba(255, 255, 255, 0.17);
  content: "";
}

.hero-inner {
  position: relative;
  z-index: 2;
  display: flex;
  align-items: center;
  min-height: min(700px, calc(100vh - 74px));
}

.hero-copy {
  position: relative;
  z-index: 3;
  width: min(620px, 58%);
  padding: 64px 0;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  margin-bottom: 18px;
  padding: 3px 12px;
  color: var(--ink);
  background: var(--green);
  border: 2px solid currentColor;
  border-radius: 4px;
  font-size: 14px;
  font-weight: 900;
}

.eyebrow.coral {
  background: var(--coral);
}

.hero h1 {
  max-width: 600px;
  margin: 0 0 22px;
  font-size: clamp(46px, 7vw, 84px);
  line-height: 1.08;
  letter-spacing: 0;
}

.hero-lead {
  max-width: 570px;
  margin: 0 0 28px;
  color: #e5e9e6;
  font-size: 19px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
}

.hero-note {
  color: #c6cec8;
  font-size: 14px;
}

.hero-shot {
  position: absolute;
  right: 7vw;
  bottom: 34px;
  z-index: 2;
  width: min(30vw, 320px);
  max-width: 400px;
  height: auto;
  border: 4px solid var(--white);
  border-radius: 8px;
  box-shadow: 16px 16px 0 var(--green);
  transform: rotate(3deg);
}

.hero-sticker {
  position: absolute;
  right: calc(7vw + 268px);
  bottom: 110px;
  z-index: 4;
  width: 126px;
  padding: 17px 10px;
  color: var(--ink);
  background: var(--yellow);
  border: 3px solid var(--ink);
  border-radius: 50%;
  font-size: 15px;
  font-weight: 900;
  line-height: 1.3;
  text-align: center;
  transform: rotate(-8deg);
}

.fact-strip {
  background: var(--white);
  border-bottom: 2px solid var(--ink);
}

.facts {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}

.fact {
  padding: 24px 18px;
  border-right: 2px solid var(--ink);
  text-align: center;
}

.fact:first-child {
  border-left: 2px solid var(--ink);
}

.fact strong {
  display: block;
  font-size: 22px;
  line-height: 1.25;
}

.fact span {
  color: var(--muted);
  font-size: 13px;
}

.section {
  padding: 92px 0;
}

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

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

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 30px;
  margin-bottom: 42px;
}

.section-head h2 {
  max-width: 720px;
  margin: 0;
  font-size: clamp(32px, 5vw, 52px);
  line-height: 1.16;
  letter-spacing: 0;
}

.section-index {
  color: var(--green-dark);
  font-size: 15px;
  font-weight: 900;
}

.ink .section-index {
  color: var(--green);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  border-top: 2px solid var(--ink);
  border-left: 2px solid var(--ink);
}

.feature-item {
  min-height: 210px;
  padding: 32px;
  background: var(--white);
  border-right: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
}

.feature-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  margin-bottom: 18px;
  background: var(--yellow);
  border: 2px solid var(--ink);
  border-radius: 50%;
  font-size: 14px;
  font-weight: 900;
}

.feature-item:nth-child(2) .feature-number,
.feature-item:nth-child(3) .feature-number {
  background: var(--green);
}

.feature-item h3 {
  margin: 0 0 8px;
  font-size: 24px;
  line-height: 1.25;
}

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

.preview-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 24px;
  align-items: start;
}

.preview-frame {
  margin: 0;
}

.preview-frame:nth-child(even) {
  margin-top: 48px;
}

.preview-frame img {
  width: 100%;
  max-width: 400px;
  height: auto;
  border: 3px solid var(--white);
  border-radius: 8px;
  box-shadow: 8px 8px 0 var(--green);
}

.preview-frame figcaption {
  margin-top: 18px;
  font-weight: 800;
}

.preview-frame figcaption span {
  display: block;
  color: #adb5af;
  font-size: 13px;
  font-weight: 500;
}

.path-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 26px;
}

.path-card {
  position: relative;
  min-height: 280px;
  padding: 36px;
  overflow: hidden;
  background: var(--green);
  border: 3px solid var(--ink);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.path-card.alt {
  background: var(--yellow);
}

.path-card::after {
  position: absolute;
  right: -24px;
  bottom: -68px;
  color: rgba(21, 26, 23, 0.14);
  content: attr(data-mark);
  font-size: 190px;
  font-weight: 900;
  line-height: 1;
}

.path-card h3 {
  position: relative;
  z-index: 2;
  margin: 0 0 16px;
  font-size: 31px;
  line-height: 1.2;
}

.path-card p {
  position: relative;
  z-index: 2;
  max-width: 540px;
  margin: 0 0 24px;
}

.text-link {
  position: relative;
  z-index: 2;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 2px;
  border-bottom: 2px solid currentColor;
  font-weight: 900;
}

.review-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.review {
  margin: 0;
  padding: 28px;
  background: var(--white);
  border: 2px solid var(--ink);
  border-radius: 6px;
}

.review::before {
  display: block;
  margin-bottom: 12px;
  color: var(--coral);
  content: "“";
  font-family: Georgia, serif;
  font-size: 64px;
  font-weight: 900;
  line-height: 0.6;
}

.review p {
  margin: 0 0 18px;
}

.review cite {
  color: var(--muted);
  font-size: 14px;
  font-style: normal;
  font-weight: 800;
}

.faq-list {
  border-top: 2px solid var(--ink);
}

.faq-list details {
  border-bottom: 2px solid var(--ink);
}

.faq-list summary {
  position: relative;
  padding: 23px 56px 23px 4px;
  font-size: 18px;
  font-weight: 900;
  list-style: none;
  cursor: pointer;
}

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

.faq-list summary::after {
  position: absolute;
  top: 22px;
  right: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--yellow);
  border: 2px solid var(--ink);
  border-radius: 50%;
  content: "+";
  line-height: 1;
}

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

.faq-list details p {
  max-width: 900px;
  margin: -4px 0 24px 4px;
  color: var(--muted);
}

.bottom-cta {
  padding: 64px 0;
  background: var(--coral);
  border-top: 3px solid var(--ink);
  border-bottom: 3px solid var(--ink);
}

.bottom-cta .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.bottom-cta h2 {
  max-width: 760px;
  margin: 0;
  font-size: clamp(30px, 5vw, 48px);
  line-height: 1.18;
  letter-spacing: 0;
}

.subhero {
  position: relative;
  padding: 82px 0 72px;
  overflow: hidden;
  background: var(--yellow);
  border-bottom: 3px solid var(--ink);
}

.subhero.green {
  background: var(--green);
}

.subhero::after {
  position: absolute;
  top: -70px;
  right: 5vw;
  color: rgba(21, 26, 23, 0.09);
  content: attr(data-letter);
  font-size: 340px;
  font-weight: 900;
  line-height: 1;
}

.subhero .container {
  position: relative;
  z-index: 2;
}

.breadcrumb {
  margin-bottom: 24px;
  font-size: 14px;
  font-weight: 800;
}

.breadcrumb a {
  border-bottom: 1px solid currentColor;
}

.subhero h1 {
  max-width: 860px;
  margin: 0 0 18px;
  font-size: clamp(42px, 7vw, 72px);
  line-height: 1.1;
  letter-spacing: 0;
}

.subhero p {
  max-width: 720px;
  margin: 0;
  font-size: 18px;
}

.article-layout {
  display: grid;
  grid-template-columns: 230px minmax(0, 1fr);
  gap: 64px;
  align-items: start;
}

.side-index {
  position: sticky;
  top: 102px;
  padding: 22px;
  background: var(--white);
  border: 2px solid var(--ink);
  border-radius: 6px;
  box-shadow: 5px 5px 0 var(--ink);
}

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

.side-index a {
  display: block;
  padding: 7px 0;
  color: var(--muted);
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.side-index a:hover {
  color: var(--green-dark);
}

.article-content {
  min-width: 0;
}

.article-content > p:first-child {
  margin-top: 0;
  color: #38413b;
  font-size: 19px;
}

.article-content h2 {
  margin: 68px 0 24px;
  padding-bottom: 12px;
  border-bottom: 3px solid var(--ink);
  font-size: 34px;
  line-height: 1.25;
  letter-spacing: 0;
}

.article-content h2:first-of-type {
  margin-top: 36px;
}

.article-content h3 {
  margin: 0 0 10px;
  font-size: 23px;
  line-height: 1.3;
}

.article-content p {
  margin: 0 0 18px;
}

.step-list {
  display: grid;
  gap: 24px;
}

.step {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 22px;
  padding: 28px;
  background: var(--white);
  border: 2px solid var(--ink);
  border-radius: 6px;
}

.step-number {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 54px;
  height: 54px;
  background: var(--green);
  border: 2px solid var(--ink);
  border-radius: 50%;
  font-size: 20px;
  font-weight: 900;
}

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

.guide-visual {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, 320px);
  gap: 32px;
  align-items: center;
  margin: 36px 0;
  padding: 34px;
  color: var(--white);
  background: var(--ink);
  border-radius: 8px;
}

.guide-visual img {
  width: 100%;
  max-width: 300px;
  height: auto;
  border: 3px solid var(--white);
  border-radius: 8px;
}

.guide-visual h3 {
  font-size: 30px;
}

.check-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.check-list li {
  padding: 16px 18px;
  background: var(--white);
  border: 2px solid var(--ink);
  border-radius: 6px;
}

.check-list li::before {
  margin-right: 8px;
  color: var(--green-dark);
  content: "✓";
  font-weight: 900;
}

.notice {
  margin: 28px 0;
  padding: 22px 24px;
  background: #fff7cf;
  border: 2px solid var(--ink);
  border-left: 9px solid var(--yellow);
}

.function-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.function-card {
  padding: 26px;
  background: var(--white);
  border: 2px solid var(--ink);
  border-radius: 6px;
}

.function-card:nth-child(3n + 1) {
  border-top: 8px solid var(--green);
}

.function-card:nth-child(3n + 2) {
  border-top: 8px solid var(--yellow);
}

.function-card:nth-child(3n + 3) {
  border-top: 8px solid var(--coral);
}

.function-card p {
  margin-bottom: 0;
  color: var(--muted);
}

.related-box {
  margin-top: 54px;
  padding: 30px;
  background: var(--green);
  border: 3px solid var(--ink);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.related-box h2 {
  margin: 0 0 14px;
  padding: 0;
  border: 0;
  font-size: 28px;
}

.related-box a {
  font-weight: 900;
  border-bottom: 2px solid currentColor;
}

.site-footer {
  padding: 52px 0 28px;
  color: #dce2dd;
  background: var(--ink);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.3fr 0.7fr 0.7fr;
  gap: 48px;
  padding-bottom: 38px;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
  color: var(--white);
  font-size: 24px;
  font-weight: 900;
}

.footer-brand img {
  width: 46px;
  height: 46px;
  border-radius: 8px;
}

.footer-grid p {
  max-width: 480px;
  margin: 0;
  color: #aeb8b0;
  font-size: 14px;
}

.footer-links strong {
  display: block;
  margin-bottom: 12px;
  color: var(--white);
}

.footer-links a {
  display: block;
  margin-bottom: 8px;
  color: #bdc6bf;
  font-size: 14px;
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding-top: 24px;
  color: #909b93;
  border-top: 1px solid #39423c;
  font-size: 12px;
}

.footer-bottom p {
  margin: 0;
}

@media (max-width: 940px) {
  .menu-toggle {
    display: block;
  }

  .site-nav {
    position: fixed;
    top: 74px;
    right: 0;
    left: 0;
    display: none;
    align-items: stretch;
    flex-direction: column;
    gap: 0;
    padding: 20px;
    background: var(--paper);
    border-bottom: 3px solid var(--ink);
  }

  .site-nav.open {
    display: flex;
  }

  .site-nav a:not(.download-btn) {
    padding: 13px 4px;
    border-bottom: 1px solid var(--line);
  }

  .site-nav a:not(.download-btn)::after {
    display: none;
  }

  .site-nav .download-btn {
    margin-top: 16px;
  }

  .hero-copy {
    width: 66%;
  }

  .hero-shot {
    right: 2vw;
    width: min(36vw, 310px);
    opacity: 0.72;
  }

  .hero-sticker {
    display: none;
  }

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

  .preview-frame:nth-child(even) {
    margin-top: 30px;
  }

  .article-layout {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .side-index {
    position: static;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0 18px;
  }

  .side-index strong {
    grid-column: 1 / -1;
  }
}

@media (max-width: 720px) {
  .container {
    width: min(calc(100% - 28px), var(--max));
  }

  .site-header,
  .nav-wrap {
    height: 66px;
    min-height: 66px;
  }

  .site-nav {
    top: 66px;
  }

  .brand {
    font-size: 20px;
  }

  .brand img {
    width: 40px;
    height: 40px;
  }

  .hero,
  .hero-inner {
    min-height: 720px;
  }

  .hero::before {
    display: none;
  }

  .hero-copy {
    width: 100%;
    padding: 50px 0 315px;
  }

  .hero h1 {
    font-size: clamp(42px, 12.8vw, 50px);
  }

  .hero-lead {
    max-width: 100%;
    font-size: 17px;
  }

  .hero-note {
    max-width: 145px;
    line-height: 1.5;
  }

  .hero-shot {
    right: 14px;
    bottom: 24px;
    width: 180px;
    opacity: 0.72;
    transform: rotate(7deg);
  }

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

  .fact:nth-child(odd) {
    border-left: 2px solid var(--ink);
  }

  .fact:nth-child(-n + 2) {
    border-bottom: 2px solid var(--ink);
  }

  .section {
    padding: 68px 0;
  }

  .section-head {
    align-items: start;
    flex-direction: column-reverse;
    margin-bottom: 30px;
  }

  .feature-grid,
  .path-grid,
  .review-grid,
  .function-grid,
  .check-list {
    grid-template-columns: 1fr;
  }

  .preview-grid {
    gap: 18px;
  }

  .preview-frame:nth-child(even) {
    margin-top: 0;
  }

  .preview-frame figcaption {
    font-size: 14px;
  }

  .path-card {
    min-height: 250px;
    padding: 28px;
  }

  .bottom-cta .container {
    align-items: flex-start;
    flex-direction: column;
  }

  .subhero {
    padding: 60px 0 54px;
  }

  .subhero::after {
    right: -50px;
    font-size: 250px;
  }

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

  .article-content h2 {
    margin-top: 52px;
    font-size: 29px;
  }

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

  .guide-visual {
    grid-template-columns: 1fr;
    padding: 26px;
  }

  .guide-visual img {
    justify-self: center;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 30px;
  }

  .footer-grid > div:first-child {
    grid-column: 1 / -1;
  }

  .footer-bottom {
    flex-direction: column;
  }
}

@media (max-width: 420px) {
  .hero-actions {
    align-items: flex-start;
    flex-direction: column;
  }

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

  .preview-frame img {
    width: min(100%, 330px);
    margin: 0 auto;
  }

  .side-index {
    grid-template-columns: 1fr;
  }

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

  .footer-grid > div:first-child {
    grid-column: auto;
  }
}

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

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