:root {
  --ink: #181818;
  --muted: #686868;
  --paper: #ffffff;
  --soft: #f3f5f4;
  --line: #dfe3e1;
  --red: #f44b3f;
  --red-dark: #d9362c;
  --teal: #25b6a4;
  --yellow: #ffd464;
  --max: 1180px;
}

* {
  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;
  line-height: 1.75;
}

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

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

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

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

.site-header {
  position: sticky;
  z-index: 50;
  top: 0;
  border-bottom: 1px solid rgba(24, 24, 24, 0.1);
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(14px);
}

.nav-wrap {
  display: flex;
  min-height: 72px;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 800;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 10px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  font-size: 15px;
  font-weight: 650;
}

.nav-links a:not(.download-btn):hover,
.nav-links a[aria-current="page"] {
  color: var(--red);
}

.menu-button {
  display: none;
  width: 42px;
  height: 42px;
  padding: 9px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--paper);
  cursor: pointer;
}

.menu-button span {
  display: block;
  width: 100%;
  height: 2px;
  margin: 5px 0;
  background: var(--ink);
}

.download-btn {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 10px 22px;
  border: 1px solid var(--red);
  border-radius: 6px;
  color: #fff;
  background: var(--red);
  box-shadow: 0 8px 0 rgba(244, 75, 63, 0.17);
  font-weight: 800;
  transition: transform 160ms ease, background 160ms ease;
}

.download-btn::before {
  content: "↓";
  font-size: 18px;
  line-height: 1;
}

.download-btn:hover {
  transform: translateY(-2px);
  background: var(--red-dark);
}

.download-btn.dark {
  border-color: var(--ink);
  background: var(--ink);
  box-shadow: none;
}

.hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: #f7f8f7;
}

.hero::before {
  position: absolute;
  inset: 0;
  background-image: linear-gradient(rgba(24, 24, 24, 0.045) 1px, transparent 1px), linear-gradient(90deg, rgba(24, 24, 24, 0.045) 1px, transparent 1px);
  background-size: 32px 32px;
  content: "";
  pointer-events: none;
}

.hero-grid {
  position: relative;
  min-height: 660px;
  padding: 72px 0;
}

.hero-copy {
  position: relative;
  z-index: 4;
  width: 55%;
  padding-top: 52px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 16px;
  color: var(--red);
  font-size: 13px;
  font-weight: 850;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 620px;
  margin: 0;
  font-size: 72px;
  line-height: 1.05;
  letter-spacing: 0;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 640px;
  margin: 24px 0 0;
  color: #454545;
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
  margin-top: 32px;
}

.text-link {
  border-bottom: 2px solid var(--ink);
  font-weight: 750;
}

.text-link:hover {
  color: var(--red);
  border-color: var(--red);
}

.hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
  margin: 28px 0 0;
  padding: 0;
  color: var(--muted);
  font-size: 14px;
  list-style: none;
}

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

.hero-visual {
  position: absolute;
  top: 0;
  right: -110px;
  bottom: 0;
  display: flex;
  width: 52%;
  min-height: 0;
  align-items: center;
  justify-content: center;
}

.hero-visual::after {
  position: absolute;
  z-index: 0;
  width: 74%;
  height: 74%;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--yellow);
  content: "";
}

.phone {
  position: relative;
  z-index: 2;
  width: min(270px, 52%);
  max-width: 400px;
  overflow: hidden;
  border: 8px solid var(--ink);
  border-radius: 32px;
  background: var(--ink);
  box-shadow: 18px 22px 0 rgba(37, 182, 164, 0.82);
  transform: rotate(3deg);
}

.phone.secondary {
  position: absolute;
  z-index: 1;
  left: 2%;
  width: min(210px, 42%);
  box-shadow: -14px 16px 0 rgba(244, 75, 63, 0.8);
  transform: rotate(-8deg);
}

.phone img {
  width: 100%;
}

.band {
  background: var(--ink);
  color: #fff;
}

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

.stat {
  min-height: 122px;
  padding: 26px 28px;
  border-right: 1px solid rgba(255, 255, 255, 0.18);
}

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

.stat strong {
  display: block;
  color: var(--yellow);
  font-size: 26px;
  line-height: 1.2;
}

.stat span {
  color: #c8cfcc;
  font-size: 14px;
}

.section {
  padding: 96px 0;
}

.section.alt {
  background: var(--soft);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 32px;
  margin-bottom: 42px;
}

.section h2 {
  max-width: 760px;
  margin: 0;
  font-size: 48px;
  line-height: 1.15;
  letter-spacing: 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.feature {
  min-height: 250px;
  padding: 34px;
  background: var(--paper);
}

.feature-number {
  display: inline-flex;
  width: 42px;
  height: 42px;
  align-items: center;
  justify-content: center;
  margin-bottom: 34px;
  border-radius: 50%;
  color: #fff;
  background: var(--teal);
  font-weight: 850;
}

.feature:nth-child(2n) .feature-number {
  background: var(--red);
}

.feature h3,
.topic-card h3,
.step h2,
.article-block h2 {
  margin: 0 0 12px;
  font-size: 24px;
  line-height: 1.3;
  letter-spacing: 0;
}

.feature p,
.topic-card p,
.step p,
.article-block p {
  margin: 0;
  color: var(--muted);
}

.gallery-wrap {
  position: relative;
}

.gallery {
  display: grid;
  grid-auto-columns: minmax(230px, 300px);
  grid-auto-flow: column;
  gap: 22px;
  overflow-x: auto;
  padding: 8px 2px 26px;
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scroll-snap-type: x mandatory;
}

.shot {
  margin: 0;
  scroll-snap-align: start;
}

.shot img {
  width: 100%;
  max-width: 400px;
  border: 1px solid #cfd5d2;
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 18px 40px rgba(24, 24, 24, 0.11);
}

.shot figcaption {
  padding: 14px 2px 0;
  color: var(--muted);
  font-size: 14px;
}

.gallery-controls {
  display: flex;
  gap: 8px;
}

.icon-button {
  width: 44px;
  height: 44px;
  border: 1px solid var(--ink);
  border-radius: 50%;
  color: var(--ink);
  background: var(--paper);
  font-size: 22px;
  cursor: pointer;
}

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

.deep-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 22px;
}

.topic-card {
  position: relative;
  min-height: 320px;
  padding: 38px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--paper);
}

.topic-card:first-child {
  color: #fff;
  background: var(--ink);
}

.topic-card:first-child p {
  color: #cfd5d2;
}

.topic-card .tag {
  display: inline-block;
  margin-bottom: 70px;
  padding: 5px 10px;
  border: 1px solid currentColor;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 800;
}

.topic-card .arrow {
  position: absolute;
  right: 30px;
  bottom: 24px;
  font-size: 34px;
}

.topic-card:hover .arrow {
  transform: translateX(5px);
}

.reviews {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.review {
  margin: 0;
  padding: 28px;
  border-top: 4px solid var(--red);
  background: #fff;
}

.review:nth-child(2) {
  border-color: var(--teal);
}

.review:nth-child(3) {
  border-color: var(--yellow);
}

.review p {
  margin: 0 0 24px;
  font-size: 17px;
}

.review footer {
  color: var(--muted);
  font-size: 14px;
}

.mini-faq {
  max-width: 880px;
}

details {
  border-top: 1px solid var(--line);
}

details:last-child {
  border-bottom: 1px solid var(--line);
}

summary {
  position: relative;
  padding: 22px 46px 22px 0;
  font-size: 18px;
  font-weight: 800;
  cursor: pointer;
  list-style: none;
}

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

summary::after {
  position: absolute;
  top: 18px;
  right: 6px;
  content: "+";
  font-size: 28px;
  font-weight: 400;
}

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

details p {
  max-width: 760px;
  margin: -6px 0 22px;
  color: var(--muted);
}

.cta-band {
  padding: 70px 0;
  color: #fff;
  background: var(--red);
}

.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
}

.cta-inner h2 {
  max-width: 720px;
  margin: 0;
  font-size: 48px;
  line-height: 1.15;
}

.site-footer {
  padding: 52px 0 28px;
  color: #d7ddda;
  background: var(--ink);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.6fr 0.8fr;
  gap: 54px;
  padding-bottom: 38px;
}

.footer-brand {
  color: #fff;
}

.footer-grid h3 {
  margin: 0 0 16px;
  color: #fff;
  font-size: 16px;
}

.footer-grid p,
.footer-grid a {
  margin: 0;
  color: #aeb8b3;
  font-size: 14px;
}

.footer-links {
  display: grid;
  gap: 8px;
}

.footer-grid a:hover {
  color: var(--yellow);
}

.copyright {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.15);
  color: #8e9994;
  font-size: 13px;
}

.page-hero {
  padding: 92px 0 72px;
  border-bottom: 1px solid var(--line);
  background: var(--soft);
}

.page-hero h1 {
  max-width: 880px;
  margin: 0 0 24px;
  font-size: 64px;
  line-height: 1.08;
  letter-spacing: 0;
}

.page-hero p {
  max-width: 760px;
  margin: 0;
  color: var(--muted);
  font-size: 18px;
}

.content-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 270px;
  align-items: start;
  gap: 70px;
}

.toc {
  position: sticky;
  top: 100px;
  padding: 24px;
  border-left: 3px solid var(--teal);
  background: var(--soft);
}

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

.toc a {
  display: block;
  padding: 5px 0;
  color: var(--muted);
  font-size: 14px;
}

.toc a:hover {
  color: var(--red);
}

.step,
.article-block {
  padding: 0 0 54px;
  margin: 0 0 54px;
  border-bottom: 1px solid var(--line);
}

.step-label {
  display: inline-flex;
  min-width: 74px;
  height: 34px;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  padding: 0 12px;
  border-radius: 99px;
  color: #fff;
  background: var(--red);
  font-size: 13px;
  font-weight: 850;
}

.check-list,
.plain-list {
  display: grid;
  gap: 10px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.check-list li,
.plain-list li {
  padding-left: 25px;
  color: #4b4b4b;
}

.check-list li::before {
  margin-left: -25px;
  margin-right: 9px;
  color: var(--teal);
  content: "✓";
  font-weight: 900;
}

.plain-list li::before {
  margin-left: -25px;
  margin-right: 9px;
  color: var(--red);
  content: "—";
}

.inline-shot {
  width: min(100%, 360px);
  max-width: 400px;
  margin: 28px 0 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 16px 34px rgba(24, 24, 24, 0.1);
}

.tip {
  margin-top: 24px;
  padding: 18px 20px;
  border-left: 4px solid var(--yellow);
  background: #fff8df;
  color: #564714;
}

.faq-list details p {
  max-width: none;
}

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

.related a {
  padding: 22px;
  border: 1px solid var(--line);
  font-weight: 800;
}

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

@media (max-width: 900px) {
  .menu-button {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 72px;
    right: 0;
    left: 0;
    display: none;
    align-items: stretch;
    padding: 18px 20px 24px;
    border-bottom: 1px solid var(--line);
    background: #fff;
    flex-direction: column;
    gap: 8px;
  }

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

  .nav-links a:not(.download-btn) {
    padding: 9px 2px;
  }

  .hero-grid {
    min-height: 760px;
    padding: 52px 0 360px;
  }

  .hero-copy {
    width: 100%;
    padding-top: 0;
  }

  .hero-visual {
    top: auto;
    right: 0;
    bottom: 36px;
    width: 100%;
    height: 320px;
    min-height: 0;
  }

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

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

  .stat:nth-child(-n + 2) {
    border-bottom: 1px solid rgba(255, 255, 255, 0.18);
  }

  .deep-grid,
  .content-layout {
    grid-template-columns: 1fr;
  }

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

  .toc {
    position: static;
    order: -1;
  }

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

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

@media (max-width: 620px) {
  .container {
    width: min(100% - 28px, var(--max));
  }

  .nav-wrap {
    min-height: 64px;
  }

  .nav-links {
    top: 64px;
  }

  .brand img {
    width: 38px;
    height: 38px;
  }

  .hero h1 {
    font-size: 44px;
  }

  .hero-grid {
    min-height: 700px;
    padding: 38px 0 292px;
  }

  .hero-visual {
    bottom: 20px;
    height: 260px;
    min-height: 0;
  }

  .phone {
    width: 33%;
    border-width: 5px;
    border-radius: 20px;
    box-shadow: 9px 10px 0 rgba(37, 182, 164, 0.82);
  }

  .phone.secondary {
    left: 16%;
    width: 28%;
    box-shadow: -8px 9px 0 rgba(244, 75, 63, 0.8);
  }

  .hero-copy > p:not(.eyebrow) {
    margin-top: 16px;
    font-size: 16px;
  }

  .hero-actions {
    margin-top: 20px;
  }

  .hero-facts {
    margin-top: 18px;
  }

  .section {
    padding: 70px 0;
  }

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

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

  .feature {
    min-height: auto;
  }

  .stat {
    min-height: 104px;
    padding: 21px 16px;
  }

  .stat strong {
    font-size: 21px;
  }

  .topic-card {
    min-height: 280px;
    padding: 28px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

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

  .copyright {
    flex-direction: column;
  }

  .page-hero {
    padding: 68px 0 54px;
  }

  .page-hero h1 {
    font-size: 44px;
  }

  .section h2,
  .cta-inner h2 {
    font-size: 36px;
  }
}

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

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