:root {
  --ink: #111319;
  --paper: #f7f8f4;
  --white: #ffffff;
  --cyan: #21c7b7;
  --coral: #ff6b57;
  --yellow: #f4cf45;
  --muted: #62676f;
  --line: #d8dbd8;
  --shadow: 7px 7px 0 var(--ink);
  --max: 1180px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  overflow-x: hidden;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: radial-gradient(circle, rgba(17, 19, 25, .075) 1px, transparent 1.5px);
  background-size: 18px 18px;
}

img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
button, a { -webkit-tap-highlight-color: transparent; }

.container { width: min(calc(100% - 40px), var(--max)); margin-inline: auto; }
.skip-link { position: fixed; left: 12px; top: -80px; z-index: 100; padding: 8px 14px; background: var(--ink); color: white; }
.skip-link:focus { top: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(247, 248, 244, .96);
  border-bottom: 3px solid var(--ink);
}

.nav-wrap { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 28px; }
.brand { display: inline-flex; align-items: center; gap: 11px; font-size: 21px; font-weight: 900; white-space: nowrap; }
.brand img { width: 42px; height: 42px; border-radius: 7px; }
.nav-links { display: flex; align-items: center; gap: 7px; }
.nav-links > a:not(.btn) { padding: 9px 13px; font-weight: 700; border-bottom: 3px solid transparent; }
.nav-links > a:not(.btn):hover, .nav-links > a[aria-current="page"] { border-color: var(--coral); }
.menu-toggle { display: none; width: 44px; height: 44px; border: 2px solid var(--ink); background: var(--white); font-size: 23px; cursor: pointer; }

.btn {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  border: 3px solid var(--ink);
  border-radius: 4px;
  background: var(--cyan);
  color: var(--ink);
  font-weight: 900;
  box-shadow: 4px 4px 0 var(--ink);
  transition: transform .16s ease, box-shadow .16s ease;
}
.btn::after { content: "\2193"; margin-left: 8px; font-size: 19px; }
.btn:hover, .btn:focus-visible { transform: translate(3px, 3px); box-shadow: 1px 1px 0 var(--ink); }
.btn-dark { background: var(--cyan); color: var(--ink); box-shadow: 4px 4px 0 var(--ink); }

.hero { overflow: hidden; border-bottom: 3px solid var(--ink); background: var(--white); }
.hero-grid { min-height: 680px; display: grid; grid-template-columns: 1.02fr .98fr; align-items: center; gap: 64px; padding-block: 64px; }
.hero-grid > *, .page-hero-grid > * { min-width: 0; }
.eyebrow, .section-kicker {
  display: inline-block;
  width: fit-content;
  margin: 0 0 18px;
  padding: 3px 10px;
  background: var(--yellow);
  border: 2px solid var(--ink);
  font-size: 13px;
  font-weight: 900;
  text-transform: uppercase;
}
.hero h1 { max-width: 640px; margin: 0 0 22px; font-size: clamp(42px, 5vw, 68px); line-height: 1.08; letter-spacing: 0; }
.hero-lead { max-width: 620px; margin: 0 0 26px; color: #363a40; font-size: 19px; }
.hero-lead, .version-note { overflow-wrap: anywhere; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 17px; align-items: center; }
.version-note { font-size: 14px; color: var(--muted); font-weight: 700; }
.trust-row { display: grid; grid-template-columns: repeat(3, 1fr); max-width: 590px; margin-top: 38px; border: 3px solid var(--ink); background: var(--paper); }
.trust-item { min-width: 0; padding: 13px 12px; text-align: center; border-right: 2px solid var(--ink); }
.trust-item:last-child { border-right: 0; }
.trust-item strong { display: block; font-size: 19px; line-height: 1.25; }
.trust-item span { display: block; margin-top: 2px; color: var(--muted); font-size: 12px; }

.phone-stage { position: relative; min-height: 540px; display: grid; place-items: center; }
.phone-stage::before { content: "COPY"; position: absolute; top: 3%; right: -5%; color: rgba(33, 199, 183, .17); font-size: 108px; font-weight: 900; transform: rotate(90deg); }
.phone-frame { position: relative; z-index: 2; width: 276px; padding: 11px; border: 4px solid var(--ink); border-radius: 30px; background: var(--ink); box-shadow: 16px 16px 0 var(--cyan); transform: rotate(2deg); }
.phone-frame img { width: 100%; max-width: 356px; border-radius: 18px; }
.comic-burst { position: absolute; z-index: 3; padding: 9px 14px; border: 3px solid var(--ink); background: var(--yellow); font-size: 16px; font-weight: 900; box-shadow: 4px 4px 0 var(--ink); transform: rotate(-5deg); }
.burst-top { top: 12%; left: 4%; }
.burst-bottom { bottom: 12%; right: 0; background: var(--coral); transform: rotate(6deg); }

.band { padding-block: 88px; border-bottom: 3px solid var(--ink); }
.band-white { background: var(--white); }
.band-cyan { background: var(--cyan); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 28px; margin-bottom: 36px; }
.section-head h2 { max-width: 760px; margin: 0; font-size: clamp(30px, 3.5vw, 48px); line-height: 1.18; letter-spacing: 0; }
.section-link { border-bottom: 3px solid var(--ink); font-weight: 900; white-space: nowrap; }

.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.feature-card { min-height: 260px; padding: 24px; border: 3px solid var(--ink); border-radius: 6px; background: var(--white); box-shadow: var(--shadow); }
.feature-card:nth-child(2) { background: #dff9f4; }
.feature-card:nth-child(3) { background: #fff2c8; }
.feature-card:nth-child(4) { background: #ffe5df; }
.feature-no { display: grid; width: 48px; height: 48px; place-items: center; margin-bottom: 30px; border: 3px solid var(--ink); border-radius: 50%; background: var(--ink); color: var(--white); font-weight: 900; }
.feature-card h3 { margin: 0 0 10px; font-size: 21px; }
.feature-card p { margin: 0; color: #44484e; }

.screens-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; align-items: start; }
.screen-card { margin: 0; }
.screen-shell { padding: 9px; border: 3px solid var(--ink); border-radius: 24px; background: var(--ink); box-shadow: 7px 7px 0 var(--coral); }
.screen-shell img { width: 100%; max-width: 356px; margin: auto; border-radius: 15px; }
.screen-card figcaption { padding: 18px 6px 0; font-weight: 900; }
.screen-card figcaption span { display: block; color: var(--muted); font-size: 13px; font-weight: 500; }

.path-grid { display: grid; grid-template-columns: .9fr 1.1fr; gap: 44px; align-items: stretch; }
.path-intro { padding: 34px; border: 3px solid var(--ink); background: var(--ink); color: var(--white); }
.path-intro h2 { margin: 0 0 18px; font-size: 40px; line-height: 1.2; }
.path-intro p { color: #dfe2e3; }
.path-intro .btn { margin-top: 18px; }
.path-list { display: grid; gap: 14px; counter-reset: path; }
.path-item { position: relative; min-height: 118px; padding: 22px 22px 22px 78px; border: 3px solid var(--ink); background: var(--white); }
.path-item::before { counter-increment: path; content: counter(path); position: absolute; left: 20px; top: 22px; display: grid; width: 38px; height: 38px; place-items: center; border: 2px solid var(--ink); background: var(--yellow); font-weight: 900; }
.path-item h3 { margin: 0 0 4px; font-size: 18px; }
.path-item p { margin: 0; color: var(--muted); }

.quote-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.quote { margin: 0; padding: 26px; border: 3px solid var(--ink); background: var(--white); box-shadow: 6px 6px 0 var(--ink); }
.quote p { margin: 0 0 18px; font-size: 17px; }
.quote footer { color: var(--muted); font-size: 13px; font-weight: 800; }

.faq-preview { display: grid; grid-template-columns: 1fr 1fr; border: 3px solid var(--ink); background: var(--white); }
.faq-preview article { padding: 26px; border-bottom: 2px solid var(--ink); }
.faq-preview article:nth-child(odd) { border-right: 2px solid var(--ink); }
.faq-preview article:nth-last-child(-n+2) { border-bottom: 0; }
.faq-preview h3 { margin: 0 0 8px; font-size: 18px; }
.faq-preview p { margin: 0; color: var(--muted); }

.download-band { padding-block: 68px; background: var(--coral); border-bottom: 3px solid var(--ink); }
.download-layout { display: flex; align-items: center; justify-content: space-between; gap: 32px; }
.download-layout h2 { margin: 0; max-width: 720px; font-size: clamp(30px, 4vw, 52px); line-height: 1.15; }

.page-hero { padding-block: 74px 58px; background: var(--white); border-bottom: 3px solid var(--ink); }
.page-hero-grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 56px; align-items: center; }
.page-hero h1 { margin: 0 0 18px; font-size: clamp(38px, 5vw, 62px); line-height: 1.12; letter-spacing: 0; }
.page-hero p { max-width: 720px; margin: 0; color: var(--muted); font-size: 18px; }
.page-index { display: grid; grid-template-columns: repeat(3, 1fr); border: 3px solid var(--ink); }
.page-index a { padding: 16px; background: var(--paper); border-right: 2px solid var(--ink); font-weight: 900; text-align: center; }
.page-index a:last-child { border-right: 0; }

.content-layout { display: grid; grid-template-columns: minmax(0, 1fr) 290px; gap: 42px; align-items: start; }
.article-stack { display: grid; gap: 22px; }
.guide-step { display: grid; grid-template-columns: 76px 1fr; gap: 22px; padding: 28px; border: 3px solid var(--ink); background: var(--white); box-shadow: 6px 6px 0 var(--ink); }
.step-no { display: grid; width: 62px; height: 62px; place-items: center; background: var(--cyan); border: 3px solid var(--ink); font-size: 24px; font-weight: 900; }
.guide-step h2 { margin: 0 0 10px; font-size: 26px; }
.guide-step p { margin: 0 0 12px; }
.guide-step ul { margin: 10px 0 0; padding-left: 20px; }
.tip-box { padding: 24px; border: 3px solid var(--ink); background: #fff2c8; }
.tip-box h2 { margin: 0 0 10px; font-size: 23px; }
.tip-box p { margin: 0; }

.side-nav { position: sticky; top: 104px; border: 3px solid var(--ink); background: var(--white); }
.side-nav strong { display: block; padding: 14px 18px; background: var(--ink); color: white; }
.side-nav a { display: block; padding: 12px 18px; border-bottom: 1px solid var(--line); font-weight: 700; }
.side-nav a:last-child { border-bottom: 0; }
.side-nav a:hover { background: #dff9f4; }

.function-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-bottom: 50px; }
.function-panel { padding: 26px; border: 3px solid var(--ink); background: var(--white); }
.function-panel:nth-child(2) { background: #dff9f4; }
.function-panel:nth-child(3) { background: #fff2c8; }
.function-panel:nth-child(4) { background: #ffe5df; }
.function-panel h2 { margin: 0 0 12px; font-size: 24px; }
.function-panel p { margin: 0; }
.text-link { font-weight: 900; border-bottom: 2px solid var(--coral); }

.faq-list { display: grid; gap: 12px; }
.faq-item { border: 3px solid var(--ink); background: var(--white); }
.faq-question { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 18px 20px; border: 0; background: transparent; color: var(--ink); font: inherit; font-size: 18px; font-weight: 900; text-align: left; cursor: pointer; }
.faq-question::after { content: "+"; flex: 0 0 auto; font-size: 27px; }
.faq-question[aria-expanded="true"]::after { content: "\2212"; }
.faq-answer { padding: 0 20px 20px; color: #4d5158; }
.faq-answer[hidden] { display: none; }
.faq-answer p { margin: 0; }

.site-footer { padding-block: 46px 24px; background: var(--ink); color: var(--white); }
.footer-grid { display: grid; grid-template-columns: 1.2fr .8fr .8fr; gap: 42px; }
.footer-brand { margin-bottom: 14px; }
.footer-brand img { border: 2px solid var(--white); }
.footer-copy { max-width: 480px; color: #bfc3c8; }
.footer-col strong { display: block; margin-bottom: 12px; }
.footer-col a { display: block; width: fit-content; margin: 7px 0; color: #d9dcdf; }
.footer-col a:hover { color: var(--cyan); }
.disclaimer { margin-top: 34px; padding-top: 22px; border-top: 1px solid #41444a; color: #afb3b8; font-size: 13px; }
.copyright { display: flex; justify-content: space-between; gap: 20px; margin-top: 10px; color: #83888e; font-size: 12px; }

@media (max-width: 980px) {
  .hero-grid, .page-hero-grid, .path-grid { grid-template-columns: 1fr; }
  .hero-grid { padding-block: 52px; }
  .hero-copy { order: 1; }
  .phone-stage { order: 2; min-height: 500px; }
  .feature-grid, .screens-grid { grid-template-columns: repeat(2, 1fr); }
  .content-layout { grid-template-columns: 1fr; }
  .side-nav { position: static; order: -1; display: grid; grid-template-columns: repeat(3, 1fr); }
  .side-nav strong { grid-column: 1 / -1; }
  .side-nav a { text-align: center; border-right: 1px solid var(--line); }
}

@media (max-width: 760px) {
  .container { width: min(calc(100% - 26px), var(--max)); }
  .nav-wrap { min-height: 66px; }
  .brand { font-size: 18px; }
  .brand img { width: 38px; height: 38px; }
  .menu-toggle { display: block; }
  .nav-links { display: none; position: absolute; top: 66px; left: 0; right: 0; padding: 14px 13px 20px; background: var(--paper); border-bottom: 3px solid var(--ink); flex-direction: column; align-items: stretch; }
  .nav-links.is-open { display: flex; }
  .nav-links > a { text-align: center; }
  .hero-grid { min-height: auto; gap: 26px; padding-block: 42px; }
  .hero h1 { font-size: 44px; }
  .hero-lead { font-size: 17px; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .hero-actions .btn { width: 100%; }
  .trust-row { grid-template-columns: 1fr; }
  .trust-item { border-right: 0; border-bottom: 2px solid var(--ink); }
  .trust-item:last-child { border-bottom: 0; }
  .phone-stage { min-height: 450px; }
  .phone-frame { width: 235px; }
  .phone-stage::before { display: none; }
  .band { padding-block: 60px; }
  .section-head { align-items: start; flex-direction: column; margin-bottom: 28px; }
  .feature-grid, .screens-grid, .quote-grid, .function-grid { grid-template-columns: 1fr; }
  .screens-grid { gap: 34px; }
  .screen-shell { max-width: 300px; margin-inline: auto; }
  .faq-preview { grid-template-columns: 1fr; }
  .faq-preview article, .faq-preview article:nth-child(odd), .faq-preview article:nth-last-child(-n+2) { border-right: 0; border-bottom: 2px solid var(--ink); }
  .faq-preview article:last-child { border-bottom: 0; }
  .download-layout { align-items: stretch; flex-direction: column; }
  .page-index, .side-nav { grid-template-columns: 1fr; }
  .page-index a { border-right: 0; border-bottom: 2px solid var(--ink); }
  .page-index a:last-child { border-bottom: 0; }
  .guide-step { grid-template-columns: 1fr; padding: 22px; }
  .footer-grid { grid-template-columns: 1fr; gap: 26px; }
  .copyright { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; }
}