:root {
  --ink: #171927;
  --paper: #f7f7f2;
  --white: #ffffff;
  --coral: #ff5a5f;
  --teal: #23b6aa;
  --yellow: #ffc857;
  --muted: #666978;
  --line: #d9d9d2;
  --shadow: 7px 7px 0 var(--ink);
}

* {
  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;
  letter-spacing: 0;
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image: radial-gradient(#17192716 1px, transparent 1px);
  background-size: 16px 16px;
  content: "";
  pointer-events: none;
}

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

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

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

button {
  font: inherit;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 8px 14px;
  color: var(--white);
  background: var(--ink);
  transform: translateY(-160%);
}

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 3px solid var(--ink);
  background: rgb(247 247 242 / 96%);
  backdrop-filter: blur(12px);
}

.nav-wrap {
  display: flex;
  min-height: 74px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  flex: none;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 900;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 7px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.site-nav a {
  padding: 9px 12px;
  border-bottom: 3px solid transparent;
  font-size: 0.94rem;
  font-weight: 700;
}

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

.menu-button {
  display: none;
  width: 42px;
  height: 42px;
  padding: 9px;
  border: 2px solid var(--ink);
  border-radius: 4px;
  background: var(--white);
  cursor: pointer;
}

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

.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  border: 2px solid var(--ink);
  border-radius: 4px;
  color: var(--ink);
  background: var(--yellow);
  box-shadow: 4px 4px 0 var(--ink);
  font-weight: 900;
  transition: transform 160ms ease, box-shadow 160ms ease;
}

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

.button--coral {
  color: var(--white);
  background: var(--coral);
}

.button--small {
  min-height: 40px;
  padding: 7px 16px;
  box-shadow: 3px 3px 0 var(--ink);
}

.hero {
  overflow: hidden;
  border-bottom: 3px solid var(--ink);
  background: var(--white);
}

.hero-grid {
  display: grid;
  min-height: 620px;
  grid-template-columns: minmax(0, 1.08fr) minmax(330px, 0.92fr);
  align-items: center;
  gap: 72px;
  padding: 64px 0 52px;
}

.eyebrow {
  display: inline-block;
  margin: 0 0 18px;
  padding: 5px 10px;
  border: 2px solid var(--ink);
  background: var(--teal);
  box-shadow: 3px 3px 0 var(--ink);
  font-size: 0.78rem;
  font-weight: 900;
  text-transform: uppercase;
}

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

h1,
h2,
h3 {
  line-height: 1.25;
  letter-spacing: 0;
}

h1 {
  max-width: 650px;
  margin-bottom: 22px;
  font-size: clamp(2.5rem, 7vw, 5.4rem);
  font-weight: 950;
}

h2 {
  margin-bottom: 28px;
  font-size: clamp(1.85rem, 4vw, 3.1rem);
  font-weight: 950;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.2rem;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 640px;
  margin-bottom: 28px;
  color: #454754;
  font-size: 1.08rem;
}

.hero-actions,
.link-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
}

.text-link {
  border-bottom: 2px solid var(--coral);
  font-weight: 900;
}

.hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.hero-facts li {
  padding: 5px 10px;
  border: 1px solid var(--line);
  background: var(--paper);
  font-size: 0.84rem;
  font-weight: 800;
}

.phone-stage {
  position: relative;
  display: flex;
  min-height: 490px;
  align-items: center;
  justify-content: center;
}

.phone-stage::before {
  position: absolute;
  inset: 46px 0 26px 40px;
  border: 3px solid var(--ink);
  background: var(--teal);
  box-shadow: 10px 10px 0 var(--ink);
  content: "";
  transform: rotate(3deg);
}

.phone-stage img {
  position: relative;
  z-index: 2;
  width: min(280px, 76vw);
  max-width: 400px;
  height: auto;
  border: 8px solid var(--ink);
  border-radius: 24px;
  box-shadow: 14px 14px 0 rgb(23 25 39 / 22%);
}

.panel-tag {
  position: absolute;
  right: 8px;
  bottom: 58px;
  z-index: 3;
  padding: 8px 14px;
  border: 2px solid var(--ink);
  background: var(--yellow);
  box-shadow: 4px 4px 0 var(--ink);
  font-weight: 950;
  transform: rotate(-2deg);
}

.section {
  padding: 82px 0;
}

.section--white {
  border-block: 3px solid var(--ink);
  background: var(--white);
}

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

.section-kicker {
  display: block;
  margin-bottom: 8px;
  color: var(--coral);
  font-size: 0.78rem;
  font-weight: 900;
  text-transform: uppercase;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
}

.section-heading h2 {
  margin-bottom: 28px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 2px solid var(--ink);
  border-left: 2px solid var(--ink);
}

.feature-item {
  min-height: 220px;
  padding: 26px;
  border-right: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
  background: var(--white);
}

.feature-index {
  display: inline-flex;
  width: 40px;
  height: 40px;
  margin-bottom: 22px;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--yellow);
  font-weight: 950;
}

.feature-item:nth-child(2n) .feature-index {
  background: var(--teal);
}

.feature-item:nth-child(3n) .feature-index {
  color: var(--white);
  background: var(--coral);
}

.feature-item p,
.guide-card p,
.review-card p,
.manual-block p,
.feature-detail p {
  margin-bottom: 0;
  color: var(--muted);
}

.screenshot-controls {
  display: flex;
  gap: 8px;
  margin-bottom: 28px;
}

.icon-button {
  width: 44px;
  height: 44px;
  border: 2px solid var(--ink);
  border-radius: 4px;
  background: var(--white);
  box-shadow: 3px 3px 0 var(--ink);
  cursor: pointer;
  font-size: 1.3rem;
  font-weight: 900;
}

.screenshot-rail {
  display: grid;
  grid-auto-columns: 380px;
  grid-auto-flow: column;
  gap: 22px;
  overflow-x: auto;
  padding: 4px 10px 24px 4px;
  scroll-snap-type: x mandatory;
  scrollbar-color: var(--coral) var(--paper);
}

.shot {
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: 6px;
  background: var(--white);
  box-shadow: 6px 6px 0 var(--ink);
  scroll-snap-align: start;
}

.shot img {
  width: 100%;
  max-width: 400px;
  height: auto;
  border-bottom: 2px solid var(--ink);
}

.shot figcaption {
  min-height: 108px;
  padding: 16px;
}

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

.shot span {
  color: var(--muted);
  font-size: 0.9rem;
}

.guide-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.guide-card {
  position: relative;
  min-height: 260px;
  padding: 30px;
  border: 2px solid var(--ink);
  border-radius: 6px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.guide-card .label {
  display: inline-block;
  margin-bottom: 30px;
  padding: 4px 9px;
  color: var(--white);
  background: var(--coral);
  font-size: 0.75rem;
  font-weight: 900;
}

.guide-card a {
  display: inline-block;
  margin-top: 22px;
  border-bottom: 2px solid var(--teal);
  font-weight: 900;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border: 2px solid var(--white);
}

.stat {
  padding: 28px 18px;
  border-right: 2px solid var(--white);
  text-align: center;
}

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

.stat strong {
  display: block;
  color: var(--yellow);
  font-size: 2rem;
}

.reviews {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 34px;
}

.review-card {
  padding: 24px;
  border: 2px solid var(--white);
  border-radius: 6px;
  background: #242637;
}

.review-card p {
  color: #ececf1;
}

.review-card footer {
  margin-top: 18px;
  color: var(--teal);
  font-weight: 900;
}

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

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

.faq-question {
  display: grid;
  width: 100%;
  grid-template-columns: 1fr 32px;
  align-items: center;
  gap: 16px;
  padding: 20px 4px;
  border: 0;
  color: var(--ink);
  background: transparent;
  cursor: pointer;
  text-align: left;
  font-weight: 900;
}

.faq-question::after {
  content: "+";
  font-size: 1.5rem;
  text-align: center;
}

.faq-item.is-open .faq-question::after {
  content: "−";
}

.faq-answer {
  display: none;
  max-width: 900px;
  padding: 0 44px 22px 4px;
  color: var(--muted);
}

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

.faq-item.is-open .faq-answer {
  display: block;
}

.download-band {
  border-block: 3px solid var(--ink);
  background: var(--coral);
}

.download-inner {
  display: flex;
  min-height: 230px;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
}

.download-inner h2 {
  max-width: 670px;
  margin-bottom: 8px;
  color: var(--white);
}

.download-inner p {
  margin-bottom: 0;
  color: #fff4f4;
}

.page-hero {
  border-bottom: 3px solid var(--ink);
  background: var(--white);
}

.page-hero-inner {
  display: grid;
  min-height: 430px;
  grid-template-columns: minmax(0, 1fr) 360px;
  align-items: center;
  gap: 64px;
  padding: 58px 0;
}

.page-hero h1 {
  font-size: clamp(2.3rem, 6vw, 4.6rem);
}

.page-hero .summary {
  max-width: 680px;
  color: var(--muted);
  font-size: 1.05rem;
}

.chapter-mark {
  display: flex;
  width: 260px;
  aspect-ratio: 1;
  align-items: center;
  justify-content: center;
  border: 4px solid var(--ink);
  border-radius: 50%;
  color: var(--white);
  background: var(--teal);
  box-shadow: 12px 12px 0 var(--ink);
  font-size: 5rem;
  font-weight: 950;
  transform: rotate(4deg);
}

.toc {
  padding: 24px;
  border: 2px solid var(--ink);
  background: var(--yellow);
  box-shadow: 6px 6px 0 var(--ink);
}

.toc strong {
  display: block;
  margin-bottom: 10px;
}

.toc ol {
  margin: 0;
  padding-left: 22px;
}

.toc a {
  border-bottom: 1px solid var(--ink);
}

.manual-layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  align-items: start;
  gap: 56px;
}

.manual-layout .toc {
  position: sticky;
  top: 98px;
}

.manual-block {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 22px;
  padding: 34px 0;
  border-bottom: 2px solid var(--ink);
}

.step-number {
  display: flex;
  width: 64px;
  height: 64px;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--coral);
  color: var(--white);
  font-size: 1.35rem;
  font-weight: 950;
}

.manual-block ul,
.feature-detail ul {
  padding-left: 20px;
}

.manual-block li,
.feature-detail li {
  margin-bottom: 8px;
}

.note {
  margin-top: 18px;
  padding: 16px 18px;
  border-left: 6px solid var(--teal);
  background: #eaf8f6;
}

.warning {
  border-left-color: var(--coral);
  background: #fff0f0;
}

.feature-details {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.feature-detail {
  padding: 28px;
  border: 2px solid var(--ink);
  border-radius: 6px;
  background: var(--white);
  box-shadow: 5px 5px 0 var(--ink);
}

.feature-detail .mini-tag {
  display: inline-block;
  margin-bottom: 16px;
  padding: 3px 8px;
  background: var(--teal);
  font-size: 0.76rem;
  font-weight: 900;
}

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

.related a {
  padding: 22px;
  border: 2px solid var(--ink);
  background: var(--white);
  box-shadow: 4px 4px 0 var(--ink);
  font-weight: 900;
}

.site-footer {
  padding: 48px 0 30px;
  color: #d7d8df;
  background: var(--ink);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr 0.8fr;
  gap: 48px;
}

.footer-brand {
  color: var(--white);
}

.site-footer h3 {
  color: var(--white);
  font-size: 1rem;
}

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

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

.disclaimer {
  margin: 34px 0 0;
  padding-top: 22px;
  border-top: 1px solid #46485a;
  color: #afb0bc;
  font-size: 0.82rem;
}

.copyright {
  margin: 10px 0 0;
  color: #868896;
  font-size: 0.8rem;
}

@media (max-width: 900px) {
  .hero-grid,
  .page-hero-inner {
    grid-template-columns: 1fr;
  }

  .hero-grid {
    gap: 30px;
    padding-top: 48px;
  }

  .phone-stage {
    min-height: 460px;
  }

  .page-hero-inner {
    gap: 32px;
  }

  .chapter-mark {
    width: 190px;
    font-size: 4rem;
  }

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

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

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

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

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

  .manual-layout .toc {
    position: static;
  }

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

@media (max-width: 720px) {
  .container {
    width: min(100% - 28px, 1160px);
  }

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

  .menu-button {
    display: block;
    visibility: visible;
    flex: 0 0 42px;
    position: relative;
    z-index: 2;
  }

  .site-nav {
    position: absolute;
    top: 66px;
    right: 0;
    left: 0;
    display: none;
    padding: 10px 14px 18px;
    border-bottom: 3px solid var(--ink);
    background: var(--paper);
  }

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

  .screenshot-rail {
    grid-auto-columns: min(340px, calc(100vw - 52px));
  }

  .site-nav a {
    padding: 12px;
    border: 0;
    border-bottom: 1px solid var(--line);
  }

  .site-nav .button {
    margin-top: 8px;
  }

  h1 {
    font-size: 2.7rem;
  }

  h2 {
    font-size: 2rem;
  }

  .hero-grid {
    min-height: auto;
    gap: 14px;
    padding: 32px 0 0;
  }

  .hero-copy > p:not(.eyebrow) {
    margin-bottom: 20px;
  }

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

  .phone-stage {
    height: 250px;
    min-height: 250px;
    align-items: flex-start;
    overflow: hidden;
  }

  .phone-stage::before {
    inset: 24px 36px -90px 36px;
  }

  .phone-stage img {
    width: 150px;
    border-width: 5px;
    border-radius: 18px;
  }

  .panel-tag {
    right: 38px;
    bottom: 28px;
  }

  .section {
    padding: 32px 0 48px;
  }

  .feature-grid,
  .guide-grid,
  .reviews,
  .feature-details,
  .related,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .feature-item {
    min-height: auto;
  }

  .section-heading {
    display: block;
  }

  .download-inner {
    min-height: 270px;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
  }

  .manual-block {
    grid-template-columns: 1fr;
  }

  .page-hero-inner {
    min-height: auto;
    padding: 42px 0;
  }
}

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

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