:root {
  --red: #ef4f45;
  --red-deep: #d9363f;
  --navy: #202b3e;
  --navy-soft: #2b374c;
  --gold: #f2b94b;
  --ink: #222832;
  --muted: #747d8b;
  --line: #e5e8ed;
  --surface: #f5f7f9;
  --white: #fff;
  --shell: 1160px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); font-family: "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif; background: var(--white); }
a { color: inherit; text-decoration: none; }
button, a { -webkit-tap-highlight-color: transparent; }

.site-header { position: sticky; top: 0; z-index: 50; background: rgba(255,255,255,.96); border-bottom: 1px solid var(--line); backdrop-filter: blur(14px); }
.nav-shell { display: flex; align-items: center; justify-content: space-between; width: min(calc(100% - 40px), var(--shell)); height: 70px; margin: 0 auto; }
.brand, .footer-brand { display: inline-flex; align-items: center; gap: 11px; font-weight: 800; }
.brand img { width: 38px; height: 38px; }
.brand span { font-size: 19px; }
.nav-links { display: flex; align-items: center; gap: 34px; color: #4f5866; font-size: 14px; }
.nav-links a:hover { color: var(--red-deep); }
.nav-download { padding: 11px 18px; color: var(--white) !important; font-weight: 700; background: var(--red); border-radius: 8px; }
.menu-toggle { display: none; width: 42px; height: 42px; padding: 0; color: var(--navy); font-size: 24px; background: transparent; border: 0; }

.hero { position: relative; isolation: isolate; display: flex; align-items: center; min-height: clamp(560px, calc(100svh - 140px), 760px); overflow: hidden; color: var(--white); background: var(--navy); }
.hero::after { position: absolute; right: 0; bottom: 0; left: 0; z-index: -1; height: 8px; content: ""; background: var(--gold); }
.hero-mark { position: absolute; right: max(4vw, calc((100vw - var(--shell)) / 2)); width: min(48vw, 590px); height: min(48vw, 590px); object-fit: contain; opacity: .92; }
.hero-inner { position: relative; z-index: 2; width: min(calc(100% - 40px), var(--shell)); margin: 0 auto; padding: 72px 0 78px; }
.eyebrow { margin: 0 0 18px; color: var(--gold); font-size: 14px; font-weight: 800; }
.hero h1 { max-width: 620px; margin: 0; font-size: clamp(58px, 8vw, 104px); line-height: 1; letter-spacing: 0; }
.hero-copy { max-width: 540px; margin: 26px 0 0; overflow-wrap: anywhere; color: #d6dce5; font-size: clamp(18px, 2vw, 24px); line-height: 1.75; }
.hero-actions { display: flex; gap: 14px; margin-top: 36px; }
.hero-actions a { display: inline-flex; align-items: center; justify-content: center; min-width: 126px; height: 48px; padding: 0 20px; font-size: 15px; font-weight: 700; border-radius: 8px; }
.primary-action { color: var(--white); background: var(--red); }
.secondary-action { color: var(--white); border: 1px solid #687386; }
.hero-meta { display: flex; gap: 0; margin-top: 54px; color: #aeb7c5; font-size: 13px; }
.hero-meta span { padding: 0 22px; border-left: 1px solid #485469; }
.hero-meta span:first-child { padding-left: 0; border-left: 0; }

.section-shell { width: min(calc(100% - 40px), var(--shell)); margin: 0 auto; }
.feature-band { padding: 92px 0 100px; }
.section-heading { display: grid; grid-template-columns: 64px 1fr; align-items: start; max-width: 760px; }
.section-index { margin: 0; color: var(--red); font-size: 13px; font-weight: 800; }
.section-heading h2, .product-copy h2, .about-layout h2, .download-inner h2 { margin: 0; font-size: clamp(34px, 4vw, 52px); line-height: 1.25; letter-spacing: 0; }
.section-heading p:not(.section-index), .product-copy > p, .download-inner p { margin: 14px 0 0; color: var(--muted); line-height: 1.8; }
.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); margin-top: 68px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.feature-item { min-height: 260px; padding: 38px 40px 44px; border-left: 1px solid var(--line); }
.feature-item:first-child { border-left: 0; }
.feature-number { color: var(--red); font-size: 13px; font-weight: 800; }
.feature-item h3 { margin: 42px 0 14px; font-size: 24px; }
.feature-item p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.85; }

.product-section { padding: 106px 0; background: var(--surface); }
.product-layout { display: grid; grid-template-columns: .9fr 1.1fr; align-items: center; gap: 92px; }
.product-copy > p { max-width: 480px; }
.product-copy .section-index { margin-bottom: 20px; }
.product-points { margin: 38px 0 0; padding: 0; list-style: none; border-top: 1px solid #dce1e7; }
.product-points li { display: flex; align-items: center; padding: 18px 0; color: #596271; border-bottom: 1px solid #dce1e7; }
.product-points span { width: 64px; color: var(--red-deep); font-weight: 800; }
.phone-preview { width: min(100%, 470px); margin-left: auto; padding: 16px 18px 24px; overflow: hidden; background: var(--white); border: 8px solid var(--navy); border-radius: 30px; box-shadow: 0 28px 70px rgba(32,43,62,.16); }
.phone-top { display: flex; justify-content: space-between; padding: 4px 8px 14px; color: var(--navy); font-size: 11px; font-weight: 800; }
.app-toolbar { display: flex; align-items: center; padding: 11px 4px 16px; border-bottom: 1px solid var(--line); }
.app-toolbar img { width: 42px; height: 42px; }
.app-toolbar div { display: flex; min-width: 0; flex: 1; flex-direction: column; margin-left: 11px; }
.app-toolbar strong { font-size: 16px; }
.app-toolbar small { margin-top: 3px; color: #929aa6; }
.app-toolbar button { display: flex; align-items: center; justify-content: center; width: 38px; height: 38px; padding: 0; color: var(--red-deep); font-size: 25px; background: #fff1f0; border: 0; border-radius: 8px; }
.topic-tabs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 7px; margin: 16px 0; }
.topic-tabs span { padding: 8px 4px; color: #77808c; font-size: 12px; text-align: center; background: #f1f3f6; border-radius: 6px; }
.topic-tabs .active { color: var(--white); background: var(--red); }
.preview-section-title { display: flex; align-items: center; justify-content: space-between; padding: 7px 0 12px; }
.preview-section-title strong { font-size: 15px; }
.preview-section-title span { color: #969eaa; font-size: 11px; }
.author-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; padding-bottom: 16px; border-bottom: 1px solid var(--line); }
.mini-author { display: flex; align-items: center; flex-direction: column; gap: 6px; color: #626b78; font-size: 11px; }
.mini-author b { display: flex; align-items: center; justify-content: center; width: 42px; height: 42px; color: var(--white); background: var(--navy-soft); border-radius: 50%; }
.mini-author:nth-child(even) b { background: var(--red); }
.content-list article { padding: 15px 2px; border-bottom: 1px solid var(--line); }
.content-list article:last-child { border-bottom: 0; }
.content-list article span { color: var(--red-deep); font-size: 10px; font-weight: 800; }
.content-list h3 { margin: 7px 0; overflow: hidden; font-size: 14px; text-overflow: ellipsis; white-space: nowrap; }
.content-list p { margin: 0; color: #9aa1ac; font-size: 10px; }

.about-section { padding: 108px 0; background: var(--white); }
.about-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 100px; }
.about-layout .section-index { margin-bottom: 18px; }
.about-copy { padding-top: 30px; border-top: 4px solid var(--gold); }
.about-copy p { margin: 0; color: #5f6876; font-size: 17px; line-height: 2; }
.about-copy .company-name { margin-top: 28px; color: var(--ink); font-size: 15px; font-weight: 800; }

.download-section { padding: 64px 0; color: var(--white); background: var(--red); }
.download-inner { display: grid; grid-template-columns: 94px 1fr auto; align-items: center; gap: 30px; width: min(calc(100% - 40px), var(--shell)); margin: 0 auto; }
.download-inner > img { width: 94px; height: 94px; }
.download-inner .section-index { color: #ffe1dd; }
.download-inner h2 { margin-top: 8px; font-size: 38px; }
.download-inner p { color: #ffe3df; }
.download-actions { display: flex; gap: 10px; }
.download-actions a { display: inline-flex; align-items: center; justify-content: center; height: 46px; padding: 0 18px; color: var(--white); font-size: 14px; font-weight: 700; border: 1px solid rgba(255,255,255,.58); border-radius: 8px; }
.download-actions a:hover { color: var(--red-deep); background: var(--white); }

.site-footer { color: #aeb6c3; background: #171f2e; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; width: min(calc(100% - 40px), var(--shell)); min-height: 112px; margin: 0 auto; font-size: 12px; }
.footer-brand img { width: 30px; height: 30px; }
.footer-brand span { color: var(--white); }
.footer-inner > div:last-child { display: flex; gap: 24px; }
.footer-inner a:hover { color: var(--white); }

@media (max-width: 820px) {
  .nav-shell { height: 62px; }
  .menu-toggle { position: relative; display: block; }
  .menu-toggle span { position: absolute; left: 10px; width: 22px; height: 2px; background: var(--navy); transition: transform .2s ease, opacity .2s ease; }
  .menu-toggle span:nth-child(1) { top: 13px; }
  .menu-toggle span:nth-child(2) { top: 20px; }
  .menu-toggle span:nth-child(3) { top: 27px; }
  .menu-toggle.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .menu-toggle.active span:nth-child(2) { opacity: 0; }
  .menu-toggle.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
  .nav-links { position: absolute; top: 62px; right: 16px; left: 16px; display: none; align-items: stretch; flex-direction: column; gap: 0; padding: 10px; background: var(--white); border: 1px solid var(--line); border-radius: 8px; box-shadow: 0 18px 45px rgba(32,43,62,.14); }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 13px 12px; }
  .nav-download { margin-top: 5px; text-align: center; }
  .hero { min-height: calc(100svh - 210px); }
  .hero-mark { right: -24vw; bottom: -8vw; width: 105vw; height: 105vw; opacity: .24; }
  .hero-inner { padding: 58px 0 70px; }
  .hero h1 { font-size: clamp(54px, 18vw, 76px); }
  .hero-copy { max-width: 100%; font-size: 18px; }
  .hero-meta { margin-top: 42px; }
  .feature-band, .product-section, .about-section { padding: 74px 0; }
  .section-heading { grid-template-columns: 44px 1fr; }
  .feature-grid { grid-template-columns: 1fr; margin-top: 46px; }
  .feature-item { min-height: 0; padding: 30px 20px; border-top: 1px solid var(--line); border-left: 0; }
  .feature-item:first-child { border-top: 0; }
  .feature-item h3 { margin-top: 22px; }
  .product-layout, .about-layout { grid-template-columns: 1fr; gap: 52px; }
  .phone-preview { margin: 0 auto; }
  .download-inner { grid-template-columns: 70px 1fr; gap: 18px; }
  .download-inner > img { width: 70px; height: 70px; }
  .download-inner h2 { font-size: 30px; }
  .download-actions { grid-column: 1 / -1; }
  .download-actions a { flex: 1; }
  .footer-inner { align-items: flex-start; flex-direction: column; gap: 18px; padding: 30px 0; }
}

@media (max-width: 460px) {
  .hero-actions { align-items: stretch; flex-direction: column; max-width: 220px; }
  .hero-meta span { padding: 0 12px; }
  .hero-meta { font-size: 11px; }
  .product-section { overflow: hidden; }
  .phone-preview { width: 100%; border-width: 6px; }
  .download-actions { flex-direction: column; }
}

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