:root {
  --paper: #fff;
  --ink: #181818;
  --muted: #686868;
  --rule: #e4e4e4;
  --accent: #2563eb;
  --accent-text: #2563eb;
  --accent-heading: #2563eb;
  --section: #f7f7f2;
  --accent-hover: #1d4ed8;
  --font: Arial, Helvetica, sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 32px; }
body { margin: 0; background: var(--paper); color: var(--ink); font-family: var(--font); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
a, button { -webkit-tap-highlight-color: transparent; }
a:focus-visible, button:focus-visible { outline: 2px solid var(--accent-text); outline-offset: 5px; }
a:hover { text-decoration: underline; text-underline-offset: 5px; }
.wrap { width: min(1200px, calc(100% - 112px)); margin: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; padding: 28px 0; border-bottom: 1px solid var(--rule); }
.brand { display: flex; align-items: center; gap: 13px; font-weight: 600; font-size: 23px; letter-spacing: -.7px; }
.brand img { display: block; border-radius: 6px; }
.brand-caption { display: block; margin-top: 4px; font-weight: 400; font-size: 11px; letter-spacing: .15px; color: var(--muted); }
nav { display: flex; gap: 35px; font-size: 13px; }
nav span { margin-left: 10px; color: var(--accent-text); }
nav a:hover { color: var(--accent-text); }
.hero { padding-top: 50px; padding-bottom: 75px; border-bottom: 1px solid var(--rule); }
.hero h1 { font-size: clamp(72px, 8.3vw, 116px); font-weight: 500; letter-spacing: -7px; line-height: .99; margin: 24px 0 39px; }
.hero h1 span { color: var(--accent-heading); }
.hero-bottom { display: flex; justify-content: space-between; align-items: end; gap: 40px; }
.hero-bottom p { font-size: 19px; line-height: 1.6; max-width: 490px; margin: 0; }
.text-link { color: var(--accent-text); font-size: 16px; font-weight: 400; display: inline-flex; align-items: center; gap: 28px; padding: 12px 0; border-bottom: 1px solid currentColor; white-space: nowrap; }
.section { display: grid; grid-template-columns: 1fr 1.45fr; gap: 76px; padding-top: 90px; padding-bottom: 90px; }
.section h2 { font-size: 32px; font-weight: 500; line-height: 1.18; letter-spacing: -1px; margin: 0; }
.section-content p, .product-summary > p { font-size: 15px; line-height: 1.8; color: var(--muted); margin: 0 0 20px; }
.section-content .lead, .product-summary .lead { font-size: 25px; line-height: 1.45; letter-spacing: -.5px; color: var(--ink); margin: 0 0 27px; }
.principles { margin-top: 39px; border-top: 1px solid var(--rule); }
.principles > div { display: grid; grid-template-columns: 1fr 1.2fr; gap: 22px; border-bottom: 1px solid var(--rule); padding: 19px 0; }
.principles h3 { font-size: 13px; margin: 0; font-weight: 500; }
.principles p { font-size: 12px; margin: 0; line-height: 1.65; }
.product-section { background: var(--section); }
.product-section > .wrap { padding: 65px 0 80px; }
.product-heading { display: flex; justify-content: space-between; align-items: center; gap: 24px; margin: 0 0 44px; }
.product-heading h2 { font-size: 62px; font-weight: 500; letter-spacing: -3px; margin: 0; }
.app-icon { border-radius: 24px; flex-shrink: 0; }
.product-grid { display: grid; grid-template-columns: 1fr 1.1fr; gap: 100px; }
.product-summary .lead { font-size: 24px; }
.product-summary > p { font-size: 14px; }
.product-links { margin-top: 28px; display: flex; flex-direction: column; align-items: flex-start; gap: 12px; }
.button { background: var(--accent); color: #fff; display: inline-flex; align-items: center; gap: 18px; padding: 18px 20px; font-size: 18px; font-weight: 700; line-height: 1.4; }
.button:hover { background: var(--accent-hover); text-decoration: none; }
.product-summary .small-note { font-size: 11px; margin-top: 16px; }
.features { border-top: 1px solid var(--rule); }
.features > div { padding: 25px 0; border-bottom: 1px solid var(--rule); }
.features h3 { font-size: 18px; font-weight: 500; margin: 0 0 10px; letter-spacing: -.3px; }
.features p { font-size: 13px; line-height: 1.7; color: var(--muted); margin: 0; max-width: 360px; }
.email-box { margin-top: 25px; }
.contact-reveal { background: none; border: 0; border-bottom: 1px solid currentColor; padding: 10px 0 14px; color: var(--accent-text); font-size: 16px; font-weight: 400; display: flex; gap: 24px; }
.contact-reveal:hover { color: var(--ink); }
.site-footer { padding: 40px 0 28px; }
.footer-contact { border-top: 1px solid var(--rule); padding-top: 18px; margin-top: 24px; font-size: 11px; line-height: 1.2; color: var(--muted); }
.footer-contact address { font-style: normal; }
.footer-contact p { margin: 3px 0 0; }
.footer-top, .footer-bottom { display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.footer-brand { font-size: 21px; font-weight: 600; letter-spacing: -.6px; }
.footer-identity p { font-size: 12px; color: var(--muted); margin: 9px 0 0; }
.footer-bottom { margin-top: 8px; font-size: 11px; color: var(--muted); }
.email-address { display: block; font-size: 23px; letter-spacing: -.6px; overflow-wrap: anywhere; color: var(--accent-text); }
.copy-email { border: 1px solid var(--rule); background: transparent; color: var(--ink); font-size: 14px; font-weight: 400; padding: 9px 12px; margin-top: 12px; }
.copy-status { font-size: 11px; margin-left: 12px; color: var(--muted); }
.social-links { display: flex; gap: 8px; }
.social-item { position: relative; }
.social-trigger { display: grid; place-items: center; width: 44px; height: 44px; color: var(--muted); background: transparent; border: 0; border-radius: 4px; }
.social-trigger:hover, .social-trigger[aria-expanded="true"] { background: var(--section); }
.social-logo { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 50%; color: #fff; }
.social-logo-wechat { background: #07c160; }
.social-logo-xiaohongshu { background: #ff2442; }
.social-logo-douyin { background: #111; }
.social-trigger svg { width: 18px; height: 18px; fill: currentColor; }
.social-logo-xiaohongshu svg { width: 26px; height: 26px; }
.social-trigger svg[fill="none"] { fill: none; }
.social-popover { position: absolute; z-index: 5; right: 0; bottom: calc(100% + 12px); padding: 12px; width: 264px; background: #fff; border: 1px solid var(--rule); box-shadow: 0 8px 32px #00000014; border-radius: 8px; }
.social-popover::after { content: ''; position: absolute; height: 14px; top: 100%; left: 0; right: 0; }
.social-popover img { display: block; width: 100%; height: auto; }
.skip-link { position: absolute; left: 20px; top: -80px; z-index: 10; padding: 14px; background: var(--ink); color: white; }
.skip-link:focus { top: 10px; }
.legal { max-width: 760px; padding: 75px 0 90px; }
.legal h1 { font-size: 56px; letter-spacing: -2px; font-weight: 500; }
.legal h2 { font-size: 22px; font-weight: 500; margin-top: 40px; }
.legal p { font-size: 15px; line-height: 1.8; color: var(--muted); }
.legal a { text-decoration: underline; text-underline-offset: 4px; }
.legal .contact-reveal { font-size: 16px; }
[hidden] { display: none !important; }
@media (max-width: 1000px) {
  .wrap { width: calc(100% - 72px); }
  .hero h1 { letter-spacing: -5px; }
  .section { gap: 45px; }
  .product-grid { gap: 50px; }
}
@media (max-width: 700px) {
  html { scroll-padding-top: 20px; }
  .wrap { width: calc(100% - 40px); }
  .site-header { padding: 20px 0; }
  .brand { font-size: 20px; gap: 10px; }
  .brand img { width: 38px; height: 38px; }
  .brand-caption { display: none; }
  nav { gap: 19px; font-size: 11px; }
  nav span { display: none; }
  .hero { padding-top: 28px; padding-bottom: 45px; }
  .hero h1 { font-size: clamp(40px, 12.3vw, 74px); letter-spacing: -2.7px; line-height: 1.04; margin: 20px 0 30px; }
  .hero-bottom { display: block; }
  .hero-bottom p { font-size: 16px; max-width: 390px; }
  .hero-bottom .text-link { margin-top: 22px; }
  .section { display: block; padding-top: 50px; padding-bottom: 50px; }
  .section h2 { font-size: 29px; margin: 0 0 32px; }
  .section-content .lead { font-size: 22px; }
  .section-content p { font-size: 14px; }
  .principles > div { gap: 15px; }
  .principles h3 { font-size: 12px; }
  .principles p { font-size: 11px; }
  .product-section > .wrap { padding: 40px 0 50px; }
  .product-heading { margin: 0 0 34px; gap: 15px; }
  .product-heading h2 { font-size: clamp(31px, 9vw, 39px); letter-spacing: -1.8px; }
  .app-icon { width: 64px; height: 64px; border-radius: 15px; }
  .product-grid { display: block; }
  .features { margin-top: 30px; }
  .features > div { padding: 24px 0; }
  .product-summary .lead { font-size: 23px; }
  .site-footer { padding: 30px 0 25px; }
  .button { gap: 16px; padding: 16px 18px; }
  .footer-top { flex-wrap: wrap; align-items: start; }
  .footer-brand { font-size: 19px; }
  .footer-contact { font-size: 10px; }
  .footer-bottom { align-items: start; font-size: 10px; line-height: 1.6; }
  .footer-bottom > span { max-width: 240px; }
  .social-links { position: relative; gap: 4px; margin-left: auto; }
  .social-item { position: static; }
  .social-popover { width: min(264px, calc(100vw - 40px)); right: 0; }
  .legal { padding-top: 40px; }
  .legal h1 { font-size: 42px; }
  .email-address { font-size: 22px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }