/* IrfanView 中文站：红白炭灰视觉系统，无外部字体或脚本依赖 */
:root {
  --red: #e30613;
  --red-dark: #b90711;
  --red-soft: #fff1f2;
  --ink: #24262a;
  --ink-2: #34373d;
  --muted: #62666f;
  --canvas: #f6f6f3;
  --surface: #ffffff;
  --line: #e2e3df;
  --line-dark: #41444a;
  --success: #217a4b;
  --radius: 18px;
  --radius-sm: 10px;
  --shadow: 0 14px 40px rgba(36, 38, 42, 0.08);
  --container: 1180px;
  --ease-soft: cubic-bezier(0.22, 0.61, 0.36, 1);
  --rise-y: 12px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 96px; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--canvas);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
body.modal-open { overflow: hidden; }
img { display: block; max-width: 100%; }
a { color: var(--red-dark); text-decoration: none; }
a:hover { text-decoration: underline; }
button, input, select, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 3px solid #ff7b83; outline-offset: 3px; }
::selection { color: #fff; background: var(--red); }
h1, h2, h3, h4, p, ul, ol { margin-top: 0; }
h1, h2, h3, h4 { color: var(--ink); line-height: 1.25; letter-spacing: -0.025em; }
h1 { font-size: clamp(2.35rem, 5vw, 4.6rem); }
h2 { font-size: clamp(1.8rem, 3.2vw, 2.7rem); }
h3 { font-size: 1.22rem; }
p { margin-bottom: 1rem; }
ul, ol { padding-left: 1.3rem; }
.container { width: min(calc(100% - 40px), var(--container)); margin-inline: auto; }
.narrow { width: min(calc(100% - 40px), 850px); margin-inline: auto; }
.section { padding: 88px 0; }
.section-sm { padding: 56px 0; }
.section-white { background: var(--surface); }
.section-dark { color: #d9dbe0; background: var(--ink); }
.section-dark h2, .section-dark h3 { color: #fff; }
.section-head { max-width: 720px; margin-bottom: 38px; }
.section-head.center { margin-inline: auto; text-align: center; }
.section-head h2 { margin-bottom: 14px; }
.section-head p { color: var(--muted); font-size: 1.06rem; }
.section-dark .section-head p { color: #b9bdc5; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 16px;
  color: var(--red-dark);
  font-size: 0.79rem;
  font-weight: 750;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.eyebrow::before { width: 22px; height: 3px; content: ""; background: var(--red); }
.muted { color: var(--muted); }
.small { font-size: 0.88rem; }
.text-link { display: inline-flex; align-items: center; gap: 7px; font-weight: 700; }
.text-link::after { content: "→"; transition: transform 0.2s ease; }
.text-link:hover::after { transform: translateX(3px); }
.skip-link { position: fixed; top: 10px; left: 10px; z-index: 999; padding: 8px 14px; color: #fff; background: var(--red); transform: translateY(-150%); }
.skip-link:focus { transform: translateY(0); }

/* 顶部导航 */
.site-header { position: sticky; top: 0; z-index: 50; color: #fff; background: rgba(36, 38, 42, 0.98); border-bottom: 1px solid var(--line-dark); }
.navbar { min-height: 76px; display: flex; align-items: center; gap: 34px; }
.brand { display: inline-flex; flex: 0 0 auto; align-items: center; }
.brand:hover { text-decoration: none; }
.brand img { width: 158px; height: 55px; object-fit: contain; }
.navbar > nav { margin-left: auto; }
.nav-links { display: flex; align-items: center; gap: 27px; margin: 0; padding: 0; list-style: none; }
.nav-links a { position: relative; display: block; padding: 25px 0 23px; color: #d7d9dd; font-size: 0.94rem; font-weight: 600; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: #fff; text-decoration: none; }
.nav-links a[aria-current="page"]::after { position: absolute; right: 0; bottom: 15px; left: 0; height: 3px; content: ""; background: var(--red); }
.nav-cta { margin-left: 4px; }
.nav-toggle { display: none; width: 44px; height: 44px; margin-left: auto; padding: 10px; color: #fff; background: transparent; border: 1px solid #5a5d64; border-radius: 8px; cursor: pointer; }
.nav-toggle span { display: block; height: 2px; margin: 5px 0; background: currentColor; }

/* 按钮 */
.btn {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 12px 22px;
  color: #fff;
  background: var(--red);
  border: 1px solid var(--red);
  border-radius: 8px;
  box-shadow: none;
  font-weight: 700;
  line-height: 1.3;
  cursor: pointer;
  transition: background 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}
.btn:hover { color: #fff; background: var(--red-dark); border-color: var(--red-dark); text-decoration: none; transform: translateY(-1px); }
.btn-secondary { color: var(--ink); background: #fff; border-color: #cdd0d2; }
.btn-secondary:hover { color: var(--ink); background: #f1f1ee; border-color: #aeb1b5; }
.btn-dark { color: #fff; background: var(--ink); border-color: var(--ink); }
.btn-dark:hover { background: #08090a; border-color: #08090a; }
.btn-sm { min-height: 40px; padding: 9px 17px; font-size: 0.9rem; }
.btn svg, .text-link svg { width: 18px; height: 18px; flex: 0 0 auto; fill: none; stroke: currentColor; stroke-width: 1.8; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }

/* 首页 */
.hero { position: relative; overflow: hidden; padding: 80px 0 72px; background: #fff; }
.hero::before { position: absolute; top: 0; right: 0; width: 30%; height: 5px; content: ""; background: var(--red); }
.hero-grid { display: grid; grid-template-columns: 0.94fr 1.06fr; gap: 58px; align-items: center; }
.hero-copy h1 { max-width: 650px; margin-bottom: 22px; }
.hero-copy h1 span { color: var(--red); }
.hero-lead { max-width: 600px; margin-bottom: 27px; color: var(--muted); font-size: 1.13rem; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 9px 20px; margin-top: 22px; color: var(--muted); font-size: 0.88rem; }
.hero-meta span { display: inline-flex; align-items: center; gap: 7px; }
.hero-meta span::before { width: 6px; height: 6px; content: ""; background: var(--red); border-radius: 50%; }
.hero-visual { position: relative; margin: 0; }
.hero-visual::before { position: absolute; inset: 18px -14px -14px 22px; z-index: 0; content: ""; background: var(--red-soft); border: 1px solid #ffd7da; border-radius: 16px; }
.hero-visual img { position: relative; z-index: 1; display: block; width: 100%; height: auto; border: 1px solid var(--line); border-radius: 12px; box-shadow: 0 18px 46px rgba(36, 38, 42, 0.14); }
.hero-note { position: relative; z-index: 2; max-width: 430px; margin: 16px 0 0 14px; padding-left: 12px; color: var(--muted); border-left: 3px solid var(--red); font-size: 0.84rem; line-height: 1.55; }
.fact-strip { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--canvas); }
.fact-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.fact { padding: 27px 26px; border-left: 1px solid var(--line); }
.fact:last-child { border-right: 1px solid var(--line); }
.fact strong { display: block; margin-bottom: 3px; color: var(--ink); font-size: 1.35rem; line-height: 1.3; }
.fact span { color: var(--muted); font-size: 0.86rem; }

.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 20px; }
.card { padding: 28px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); }
.card h3 { margin-bottom: 10px; }
.card p:last-child { margin-bottom: 0; }
.card-muted { color: var(--muted); }
.icon-box { display: inline-flex; width: 44px; height: 44px; align-items: center; justify-content: center; margin-bottom: 20px; color: var(--red); background: var(--red-soft); border-radius: 10px; }
.icon-box svg { width: 23px; height: 23px; fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.7; }
.advantage-card { position: relative; overflow: hidden; }
.advantage-card::after { position: absolute; right: 0; bottom: 0; left: 0; height: 3px; content: ""; background: var(--red); }
.scenario-card { padding: 0; overflow: hidden; }
.scenario-top { height: 7px; background: var(--red); }
.scenario-body { padding: 27px; }
.scenario-tag { display: inline-block; margin-bottom: 14px; padding: 3px 9px; color: var(--red-dark); background: var(--red-soft); border-radius: 4px; font-size: 0.75rem; font-weight: 700; }
.check-list { margin: 0; padding: 0; list-style: none; }
.check-list li { position: relative; margin: 10px 0; padding-left: 25px; }
.check-list li::before { position: absolute; top: 0.65em; left: 2px; width: 12px; height: 7px; content: ""; border-bottom: 2px solid var(--red); border-left: 2px solid var(--red); transform: rotate(-45deg); }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 70px; align-items: center; }
.panel { padding: 34px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.panel-dark { color: #d8dbe0; background: var(--ink-2); border-color: var(--line-dark); }
.panel-dark h3 { color: #fff; }
.quote { margin: 0; padding-left: 24px; border-left: 4px solid var(--red); font-size: 1.08rem; }
.cta-band { display: flex; align-items: center; justify-content: space-between; gap: 30px; padding: 38px 42px; color: #fff; background: var(--ink); border-radius: var(--radius); }
.cta-band h2 { margin-bottom: 8px; color: #fff; font-size: 1.75rem; }
.cta-band p { margin: 0; color: #c4c7cd; }

/* 内页 */
.page-hero { position: relative; isolation: isolate; overflow: hidden; padding: 64px 0 58px; color: #fff; background: var(--ink); border-bottom: 5px solid var(--red); }
.page-hero > .container { position: relative; z-index: 2; }
.page-hero h1 { position: relative; max-width: 840px; margin-bottom: 16px; color: #fff; font-size: clamp(2.2rem, 4.6vw, 3.7rem); }
.page-hero p { position: relative; max-width: 760px; margin-bottom: 0; color: #c5c8ce; font-size: 1.08rem; }
.page-hero .eyebrow { color: #ff8d94; }
.page-hero .eyebrow::before { background: var(--red); }

/* 英雄区装饰层：红色光晕 + 工程网格 + 镜头环 + 细颗粒，均为 aria-hidden 纯装饰 */
.page-hero-deco {
  --lens-size: 470px;
  --lens-top: -196px;
  --lens-right: max(-170px, calc(50% - 702px));
  position: absolute;
  inset: 0;
  z-index: 1;
  overflow: hidden;
  pointer-events: none;
}
.page-hero-deco::before {
  position: absolute;
  inset: 0;
  content: "";
  background:
    radial-gradient(660px 380px at 84% -16%, rgba(227, 6, 19, 0.3), transparent 70%),
    radial-gradient(460px 300px at 6% 116%, rgba(227, 6, 19, 0.12), transparent 72%);
}
.page-hero-deco .deco-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(112deg, transparent 0 37.9%, rgba(255, 255, 255, 0.055) 38% 38.18%, transparent 38.3% 100%),
    linear-gradient(112deg, transparent 0 47.4%, rgba(255, 255, 255, 0.035) 47.5% 47.68%, transparent 47.8% 100%),
    linear-gradient(rgba(255, 255, 255, 0.065) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.065) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 56px 56px, 56px 56px;
  -webkit-mask-image: radial-gradient(1080px 460px at 82% -4%, #000 0%, rgba(0, 0, 0, 0.55) 52%, transparent 80%);
  mask-image: radial-gradient(1080px 460px at 82% -4%, #000 0%, rgba(0, 0, 0, 0.55) 52%, transparent 80%);
}
.page-hero-deco .deco-lens {
  position: absolute;
  top: var(--lens-top);
  right: var(--lens-right);
  width: var(--lens-size);
  height: var(--lens-size);
  border-radius: 50%;
  background: repeating-radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.18) 0 1px, transparent 1px 52px);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.06);
  -webkit-mask-image: radial-gradient(circle at 50% 50%, transparent 0 22%, #000 23% 66%, transparent 72%);
  mask-image: radial-gradient(circle at 50% 50%, transparent 0 22%, #000 23% 66%, transparent 72%);
}
.page-hero-deco .deco-arc {
  position: absolute;
  top: var(--lens-top);
  right: var(--lens-right);
  width: var(--lens-size);
  height: var(--lens-size);
  border: 2px solid rgba(227, 6, 19, 0.62);
  border-radius: 50%;
  -webkit-mask-image: conic-gradient(from 182deg, transparent 0deg, rgba(0, 0, 0, 0.9) 34deg, rgba(0, 0, 0, 0.9) 92deg, transparent 126deg, transparent 360deg);
  mask-image: conic-gradient(from 182deg, transparent 0deg, rgba(0, 0, 0, 0.9) 34deg, rgba(0, 0, 0, 0.9) 92deg, transparent 126deg, transparent 360deg);
}
.page-hero-deco::after {
  position: absolute;
  inset: 0;
  content: "";
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.82' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E");
  opacity: 0.045;
  mix-blend-mode: soft-light;
}
.breadcrumbs { margin-bottom: 22px; color: #aeb2ba; font-size: 0.84rem; }
.breadcrumbs a { color: #fff; }
.breadcrumbs span { margin: 0 7px; }
.toc { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 28px; }
.toc a { padding: 6px 12px; color: #e6e7e9; border: 1px solid #53565d; border-radius: 6px; font-size: 0.85rem; }
.toc a:hover { color: #fff; border-color: #8d929b; text-decoration: none; }
.feature-row { display: grid; grid-template-columns: 0.75fr 1.25fr; gap: 54px; padding: 44px 0; border-bottom: 1px solid var(--line); }
.feature-row:first-child { padding-top: 0; }
.feature-row:last-child { border-bottom: 0; }
.feature-row h2 { margin-bottom: 12px; font-size: 1.7rem; }
.feature-row p { color: var(--muted); }
.feature-list { display: grid; grid-template-columns: 1fr 1fr; gap: 12px 24px; margin: 0; padding: 0; list-style: none; }
.feature-list li { padding: 13px 15px; background: #fff; border-left: 3px solid var(--red); border-radius: 0 7px 7px 0; }
.notice { padding: 20px 23px; background: #fff; border: 1px solid var(--line); border-left: 4px solid var(--red); border-radius: 0 10px 10px 0; }
.notice h3 { margin-bottom: 7px; font-size: 1rem; }
.notice p:last-child { margin-bottom: 0; }
.notice-neutral { border-left-color: #73777f; }
.table-wrap { overflow-x: auto; background: #fff; border: 1px solid var(--line); border-radius: 12px; }
table { width: 100%; border-collapse: collapse; text-align: left; }
th, td { padding: 15px 18px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--ink); background: #f0f0ed; font-size: 0.88rem; }
td { color: var(--muted); }
tr:last-child td { border-bottom: 0; }
td strong { color: var(--ink); }
.badge { display: inline-flex; align-items: center; padding: 3px 9px; color: var(--red-dark); background: var(--red-soft); border: 1px solid #ffd7da; border-radius: 999px; font-size: 0.75rem; font-weight: 700; white-space: nowrap; }
.badge-gray { color: #555a62; background: #f0f0ed; border-color: #dedfdb; }
.step-list { margin: 0; padding: 0; list-style: none; counter-reset: steps; }
.step { position: relative; display: grid; grid-template-columns: 54px minmax(0, 1fr); gap: 22px; padding-bottom: 36px; counter-increment: steps; }
.step::before { display: flex; width: 48px; height: 48px; align-items: center; justify-content: center; content: counter(steps, decimal-leading-zero); color: #fff; background: var(--ink); border-radius: 50%; font-weight: 750; }
.step::after { position: absolute; top: 52px; bottom: 4px; left: 23px; width: 2px; content: ""; background: var(--line); }
.step:last-child::after { display: none; }
.step h2, .step h3 { margin: 7px 0 10px; font-size: 1.35rem; }
.step-content { padding-bottom: 4px; }
kbd { padding: 2px 7px; color: var(--ink); background: #fff; border: 1px solid #cfd1d2; border-bottom-width: 2px; border-radius: 5px; font-family: inherit; font-size: 0.84em; white-space: nowrap; }
.code { overflow-x: auto; padding: 18px 20px; color: #f2f3f4; background: var(--ink); border-radius: 8px; font: 0.87rem/1.7 Consolas, "Courier New", monospace; }
.faq-list { display: grid; gap: 13px; }
details { background: #fff; border: 1px solid var(--line); border-radius: 10px; }
summary { position: relative; padding: 20px 52px 20px 22px; color: var(--ink); font-weight: 700; cursor: pointer; list-style: none; }
summary::-webkit-details-marker { display: none; }
summary::after { position: absolute; top: 20px; right: 22px; content: "+"; color: var(--red); font-size: 1.5rem; font-weight: 400; line-height: 1; }
details[open] summary::after { content: "−"; }
.details-body { padding: 0 22px 20px; color: var(--muted); }
.details-body p:last-child { margin-bottom: 0; }
.source-list { margin: 0; padding: 0; list-style: none; }
.source-list li { padding: 13px 0; border-bottom: 1px solid var(--line); }
.source-list li:last-child { border-bottom: 0; }
.source-list a { overflow-wrap: anywhere; }

/* 下载中心 */
.download-overview { display: grid; grid-template-columns: 1fr; gap: 28px; align-items: stretch; }
.version-card { display: grid; grid-template-columns: minmax(0, 1fr) minmax(290px, 360px); gap: 26px 56px; align-items: end; padding: 35px 40px; color: #fff; background: var(--ink); border-radius: var(--radius); }
.version-card h2 { color: #fff; }
.version-main { min-width: 0; }
.version-side { display: flex; flex-direction: column; align-items: flex-start; }
.version-side p { margin: 0; }
.version-number { margin: 5px 0 0; color: #fff; font-size: clamp(3rem, 7vw, 5.4rem); font-weight: 800; line-height: 1; letter-spacing: -0.05em; }
.version-meta { display: flex; flex-wrap: wrap; gap: 8px 20px; margin: 18px 0 24px; color: #c7cad0; font-size: 0.9rem; }
.download-card { display: flex; flex-direction: column; }
.download-card .btn { margin-top: auto; align-self: flex-start; }
.download-specs { margin: 18px 0 24px; padding: 0; list-style: none; color: var(--muted); font-size: 0.9rem; }
.download-specs li { display: flex; justify-content: space-between; gap: 16px; padding: 8px 0; border-bottom: 1px solid var(--line); }
.download-specs strong { color: var(--ink); text-align: right; }
.hash { display: block; overflow-wrap: anywhere; color: #454950; font: 0.78rem/1.65 Consolas, "Courier New", monospace; }

/* 下载弹窗：两个二维码为留空位 */
.download-dialog { width: min(calc(100% - 32px), 620px); max-height: calc(100dvh - 40px); padding: 0; color: var(--ink); background: #fff; border: 0; border-radius: 18px; box-shadow: 0 24px 80px rgba(0, 0, 0, 0.28); }
.download-dialog::backdrop { background: rgba(20, 21, 24, 0.72); backdrop-filter: blur(3px); }
.dialog-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 18px; padding: 27px 28px 18px; border-bottom: 1px solid var(--line); }
.dialog-head h2 { margin: 0 0 5px; font-size: 1.55rem; }
.dialog-head p { margin: 0; color: var(--muted); font-size: 0.9rem; }
.dialog-close { display: inline-flex; width: 40px; height: 40px; flex: 0 0 auto; align-items: center; justify-content: center; color: var(--ink); background: #f1f1ee; border: 0; border-radius: 50%; font-size: 1.6rem; line-height: 1; cursor: pointer; }
.dialog-body { padding: 25px 28px 28px; }
.qr-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.qr-item { text-align: center; }
.qr-item img { display: block;margin:0 auto; width: 80%; height: auto; margin-bottom: 13px; background: #fff; border: 1px solid var(--line); border-radius: 10px; }
.qr-item p { margin: 0; color: var(--ink); font-size: 0.91rem; font-weight: 700; }
.dialog-note { margin: 22px 0 0; padding-top: 18px; color: var(--muted); border-top: 1px solid var(--line); font-size: 0.8rem; text-align: center; }

/* 页脚 */
.site-footer { color: #b9bdc4; background: #1c1e21; border-top: 1px solid #383b40; }
.footer-main { display: grid; grid-template-columns: 1.5fr 0.75fr 0.9fr; gap: 55px; padding: 55px 0 38px; }
.footer-brand img { width: 158px; height: 55px; margin-bottom: 14px; }
.footer-brand p { max-width: 480px; font-size: 0.88rem; }
.footer-title { margin-bottom: 15px; color: #fff; font-size: 0.93rem; }
.footer-links { margin: 0; padding: 0; list-style: none; }
.footer-links li { margin: 7px 0; }
.footer-links a { color: #b9bdc4; font-size: 0.88rem; }
.footer-links a:hover { color: #fff; }
.footer-bottom { padding: 20px 0 24px; border-top: 1px solid #383b40; font-size: 0.78rem; line-height: 1.75; }
.footer-bottom p { margin: 0 0 5px; }
.footer-bottom p:last-child { margin-bottom: 0; }

@media (max-width: 1100px) {
  .page-hero-deco .deco-arc { display: none; }
  .page-hero-deco { --lens-right: -200px; }
}

@media (max-width: 1020px) {
  .navbar { gap: 20px; }
  .nav-links { gap: 18px; }
  .nav-cta { display: none; }
  .hero-grid { gap: 35px; }
  .grid-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .feature-row { grid-template-columns: 0.85fr 1.15fr; gap: 30px; }
}

@media (max-width: 780px) {
  .container, .narrow { width: min(calc(100% - 30px), var(--container)); }
  .section { padding: 62px 0; }
  .nav-toggle { display: block; }
  .navbar { min-height: 68px; flex-wrap: wrap; }
  .navbar > nav { flex: 1 1 100%; }
  .brand img { width: 142px; height: 50px; }
  .nav-links { display: none; width: 100%; flex-direction: column; align-items: center; gap: 0; padding: 4px 0 14px; }
  .nav-links.is-open { display: flex; }
  .nav-links li { width: 100%; }
  .nav-links a { padding: 13px 4px; text-align: center; }
  .nav-links li + li { border-top: 1px solid #3c3f45; }
  .nav-links a[aria-current="page"]::after { right: auto; bottom: 5px; left: 50%; width: 28px; transform: translateX(-50%); }
  .hero { padding: 54px 0 58px; }
  .hero-grid, .split, .download-overview { grid-template-columns: 1fr; }
  .page-hero-deco { --lens-size: 340px; --lens-top: -150px; --lens-right: -160px; opacity: 0.75; }
  .page-hero-deco .deco-grid { background-size: 44px 44px; }
  .page-hero-deco .deco-arc { display: none; }
  .version-card { grid-template-columns: 1fr; gap: 20px; padding: 30px 26px; }
  .hero-grid { gap: 50px; }
  .hero-copy h1 { font-size: clamp(2.35rem, 10vw, 3.5rem); }
  .hero-visual { margin-right: 10px; }
  .fact-grid { grid-template-columns: repeat(2, 1fr); }
  .fact:nth-child(3) { border-top: 1px solid var(--line); }
  .fact:nth-child(4) { border-top: 1px solid var(--line); border-right: 1px solid var(--line); }
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .feature-row { grid-template-columns: 1fr; gap: 20px; }
  .cta-band { align-items: flex-start; flex-direction: column; padding: 30px; }
  .footer-main { grid-template-columns: 1.4fr 1fr; gap: 35px; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 540px) {
  body { font-size: 15px; }
  .section { padding: 52px 0; }
  .hero-lead { font-size: 1.02rem; }
  .actions .btn { width: 100%; }
  .grid-2, .grid-3, .grid-4, .feature-list { grid-template-columns: 1fr; }
  .card, .panel { padding: 23px; }
  .fact { padding: 21px 15px; }
  .fact strong { font-size: 1.14rem; }
  .hero-note { max-width: none; margin: 13px 0 0 12px; }
  .page-hero { padding: 45px 0 42px; }
  .step { grid-template-columns: 42px minmax(0, 1fr); gap: 15px; }
  .step::before { width: 40px; height: 40px; font-size: 0.85rem; }
  .step::after { top: 44px; left: 19px; }
  .qr-grid { gap: 12px; }
  .dialog-head, .dialog-body { padding-right: 20px; padding-left: 20px; }
  .qr-item p { font-size: 0.79rem; }
  .footer-main { grid-template-columns: 1fr 1fr; gap: 28px 20px; }
}

/* ===== 动效：加载 / 滚动进入 / 悬停 / 点击 ===== */
@keyframes rise-in {
  from { opacity: 0; transform: translateY(var(--rise-y)); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes dialog-in {
  from { opacity: 0; transform: translateY(10px) scale(0.97); }
  to { opacity: 1; transform: none; }
}
@keyframes backdrop-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* 1. 页面加载：首屏文案依次淡入。h1 与主图不参与动画，避免推迟 LCP */
.hero-copy .eyebrow,
.hero-copy .hero-lead,
.hero-copy .actions,
.hero-copy .hero-meta,
.hero-note { animation: rise-in 0.55s var(--ease-soft) both; }
.hero-copy .eyebrow { animation-delay: 0.02s; }
.hero-copy .hero-lead { animation-delay: 0.08s; }
.hero-copy .actions { animation-delay: 0.15s; }
.hero-copy .hero-meta { animation-delay: 0.2s; }
.hero-note { animation-delay: 0.26s; }

/* 2. 滚动进入：脚本只对视口外元素加 .reveal，进入视口后播放一次 */
.reveal { opacity: 0; }
.reveal.is-visible {
  opacity: 1;
  animation: rise-in 0.55s var(--ease-soft) backwards;
  animation-delay: calc(var(--reveal-step, 0) * 70ms);
}

/* 3. 悬停：仅在支持悬停的精确指针设备启用，触屏不触发 */
.card, .fact { transition: transform 0.26s var(--ease-soft), box-shadow 0.26s var(--ease-soft), border-color 0.26s var(--ease-soft); }
.nav-links a, .footer-links a, .toc a { transition: color 0.2s ease, border-color 0.2s ease; }
.btn { transition: background 0.18s ease, border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease; }

@media (hover: hover) and (pointer: fine) {
  .card:hover { transform: translateY(-3px); border-color: #d5d8da; box-shadow: 0 16px 34px rgba(36, 38, 42, 0.1); }
  .icon-box { transition: transform 0.26s var(--ease-soft); }
  .card:hover .icon-box { transform: scale(1.06); }
  .footer-links a:hover { text-decoration: none; }
  .btn:hover { box-shadow: 0 6px 16px rgba(36, 38, 42, 0.12); }
  .btn:not(.btn-secondary):not(.btn-dark):hover { box-shadow: 0 6px 16px rgba(227, 6, 19, 0.2); }
}

/* 4. 点击：按钮回弹、下载弹窗进入 */
.btn:active { transform: translateY(0) scale(0.985); }
.download-dialog[open] { animation: dialog-in 0.24s var(--ease-soft) both; }
.download-dialog[open]::backdrop { animation: backdrop-in 0.24s ease both; }

@media (max-width: 780px) {
  :root { --rise-y: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .reveal { opacity: 1 !important; }
}

@media print {
  .site-header, .site-footer, .actions, .toc, .cta-band, .nav-toggle { display: none !important; }
  body { color: #000; background: #fff; }
  .section, .section-sm { padding: 24px 0; }
  .page-hero { padding: 24px 0; color: #000; background: #fff; border-bottom: 2px solid #000; }
  .page-hero h1, .page-hero p { color: #000; }
  .page-hero-deco { display: none !important; }
  a { color: #000; }
}