/* ============================================================
   Rexa 下载官网 — 设计系统
   极简白底 · 单色中性 · 大量留白
   ============================================================ */

:root {
  /* color */
  --bg: #ffffff;
  --bg-soft: #fafafa;
  --bg-sink: #f4f4f3;
  --ink: #18181b;
  --ink-2: #5f6066;
  --ink-3: #9a9aa1;
  --line: #ececec;
  --line-2: #e3e3e3;

  /* accent (default = ink, monochrome). Tweakable. */
  --accent: #18181b;
  --accent-ink: #ffffff;

  /* type */
  --font-display: "Space Grotesk", -apple-system, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;

  /* shape */
  --r-sm: 10px;
  --r-md: 14px;
  --r-lg: 18px;
  --r-xl: 24px;

  /* shadow */
  --sh-1: 0 1px 2px rgba(24,24,27,.04);
  --sh-2: 0 1px 3px rgba(24,24,27,.05), 0 10px 30px rgba(24,24,27,.05);
  --sh-3: 0 2px 6px rgba(24,24,27,.06), 0 24px 60px rgba(24,24,27,.08);

  /* rhythm */
  --maxw: 1120px;
  --pad: 32px;
}

/* background depth tweak */
[data-bg="warm"] { --bg: #fcfbf9; --bg-soft: #f7f5f1; --bg-sink: #f1eee8; --line: #ece8e1; --line-2: #e4dfd6; }
[data-bg="cool"] { --bg: #fdfdfe; --bg-soft: #f7f8fa; --bg-sink: #eef0f3; --line: #e9ebef; --line-2: #e0e3e8; }

/* radius tweak */
[data-radius="sharp"]  { --r-sm: 4px;  --r-md: 6px;  --r-lg: 8px;  --r-xl: 10px; }
[data-radius="round"]  { --r-sm: 14px; --r-md: 20px; --r-lg: 28px; --r-xl: 36px; }

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--pad); }

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

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s, background .25s;
}
.nav.scrolled { border-bottom-color: var(--line); }
.nav .wrap { display: flex; align-items: center; gap: 32px; height: 64px; }

.brand { display: flex; align-items: center; gap: 9px; font-family: var(--font-display); font-weight: 700; font-size: 21px; letter-spacing: -.01em; }
.brand .mark {
  width: 28px; height: 28px; border-radius: 8px;
  flex: none; display: block; object-fit: cover;
}

.nav-links { display: flex; gap: 28px; margin-left: 8px; }
.nav-links a { font-size: 14.5px; color: var(--ink-2); transition: color .15s; }
.nav-links a:hover { color: var(--ink); }
.nav-right { margin-left: auto; display: flex; align-items: center; gap: 14px; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  font-family: var(--font-body); font-size: 15px; font-weight: 550;
  padding: 11px 20px; border-radius: var(--r-md); border: 1px solid transparent;
  cursor: pointer; transition: transform .12s, background .18s, border-color .18s, box-shadow .18s;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: var(--accent-ink); }
.btn-primary:hover { box-shadow: 0 6px 20px color-mix(in srgb, var(--accent) 25%, transparent); }
.btn-ghost { background: var(--bg); color: var(--ink); border-color: var(--line-2); }
.btn-ghost:hover { background: var(--bg-soft); border-color: var(--ink-3); }
.btn-lg { padding: 14px 26px; font-size: 16px; }
.btn svg { width: 17px; height: 17px; }

/* ---------- hero ---------- */
.hero { padding: 86px 0 40px; text-align: center; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; color: var(--ink-2); font-weight: 500;
  border: 1px solid var(--line-2); border-radius: 999px; padding: 6px 14px;
  margin-bottom: 28px; background: var(--bg-soft);
}
.eyebrow .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }

h1.hero-title {
  font-family: var(--font-display);
  font-size: clamp(40px, 6vw, 72px); line-height: 1.04;
  font-weight: 700; letter-spacing: -.02em; color: var(--ink);
  margin: 0 auto; max-width: 14ch; text-wrap: balance;
}
.hero-sub {
  font-size: clamp(16px, 2vw, 19px); color: var(--ink-2);
  max-width: 38ch; margin: 22px auto 0; text-wrap: pretty;
}
.hero-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 34px; }
.hero-meta { margin-top: 16px; font-size: 13px; color: var(--ink-3); }
.hero-meta b { color: var(--ink-2); font-weight: 600; }

/* hero layout = split */
[data-hero="split"] .hero { text-align: left; padding: 80px 0 40px; }
[data-hero="split"] .hero .wrap { display: grid; grid-template-columns: 1.05fr 1.25fr; gap: 56px; align-items: center; }
[data-hero="split"] h1.hero-title { margin: 0; max-width: 12ch; }
[data-hero="split"] .hero-sub { margin: 22px 0 0; }
[data-hero="split"] .hero-cta { justify-content: flex-start; }
[data-hero="split"] .hero-stage { margin-top: 0; }
[data-hero="split"] .eyebrow { margin-bottom: 24px; }

.hero-copy { min-width: 0; }

/* ---------- app window mock ---------- */
.hero-stage { margin-top: 56px; }
[data-hero="split"] .hero-stage { margin-top: 0; }

.appwin {
  background: var(--bg); border: 1px solid var(--line);
  border-radius: var(--r-xl); overflow: hidden;
  box-shadow: var(--sh-3); margin: 0 auto; max-width: 1000px;
}
.appwin.in-split { max-width: none; }
.appwin-bar {
  height: 46px; display: flex; align-items: center; padding: 0 18px;
  border-bottom: 1px solid var(--line); position: relative;
}
.traffic { display: flex; gap: 8px; }
.traffic i { width: 12px; height: 12px; border-radius: 50%; display: block; }
.traffic .r { background: #ff5f57; } .traffic .y { background: #febc2e; } .traffic .g { background: #28c840; }
.appwin-bar .gear { margin-left: auto; color: var(--ink-3); display: flex; }
.appwin-bar .gear svg { width: 18px; height: 18px; }

.appwin-body {
  min-height: 360px; display: flex; flex-direction: column; align-items: center; justify-content: center;
  padding: 56px 40px; gap: 40px; background:
    radial-gradient(120% 120% at 50% 40%, var(--bg) 60%, var(--bg-soft) 100%);
}
.appwin-wordmark { font-family: var(--font-display); font-size: clamp(28px, 4vw, 44px); font-weight: 700; letter-spacing: -.01em; display: flex; align-items: center; gap: 16px; }
.appwin-wordmark .sep { color: var(--ink-3); font-weight: 300; }
.appwin-wordmark .tag { color: var(--ink-3); font-weight: 500; font-family: var(--font-body); }

.searchbar {
  width: 100%; max-width: 760px; display: flex; align-items: center; gap: 12px;
  background: var(--bg); border: 1px solid var(--line-2); border-radius: var(--r-lg);
  padding: 8px 8px 8px 18px; box-shadow: var(--sh-1);
}
.searchbar .mag { color: var(--ink-3); display: flex; flex: none; }
.searchbar .mag svg { width: 20px; height: 20px; }
.searchbar .ph { flex: 1; color: var(--ink-3); font-size: 16px; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.searchbar .ic { color: var(--ink-3); display: flex; padding: 8px; border-radius: 10px; }
.searchbar .ic svg { width: 20px; height: 20px; }
.searchbar .go {
  width: 44px; height: 44px; border-radius: 12px; flex: none;
  background: var(--bg-sink); color: var(--ink-2);
  display: flex; align-items: center; justify-content: center;
}
.searchbar .go svg { width: 18px; height: 18px; }

/* ---------- sections ---------- */
section { padding: 92px 0; }
.section-head { max-width: 620px; margin-bottom: 56px; }
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.kicker { font-size: 13px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--accent); margin-bottom: 14px; }
[data-mono-kicker="true"] .kicker { color: var(--ink-3); }
h2.section-title { font-family: var(--font-display); font-size: clamp(28px, 3.6vw, 40px); font-weight: 700; letter-spacing: -.02em; line-height: 1.1; }
.section-desc { font-size: 17px; color: var(--ink-2); margin-top: 16px; text-wrap: pretty; }

.soft { background: var(--bg-soft); }
.divide { border-top: 1px solid var(--line); }

/* feature rows */
.feature {
  display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center;
}
.feature + .feature { margin-top: 110px; }
.feature.flip .feat-visual { order: -1; }
.feat-num { font-family: var(--font-display); font-size: 14px; font-weight: 600; color: var(--ink-3); letter-spacing: .04em; }
.feat-title { font-family: var(--font-display); font-size: clamp(26px, 3vw, 34px); font-weight: 700; letter-spacing: -.02em; margin: 12px 0 16px; line-height: 1.12; }
.feat-desc { font-size: 17px; color: var(--ink-2); text-wrap: pretty; }
.feat-list { margin-top: 24px; display: flex; flex-direction: column; gap: 12px; }
.feat-list li { list-style: none; display: flex; gap: 11px; align-items: flex-start; font-size: 15.5px; color: var(--ink); }
.feat-list .ck { flex: none; width: 20px; height: 20px; border-radius: 50%; background: var(--bg-sink); color: var(--accent); display: flex; align-items: center; justify-content: center; margin-top: 2px; }
.feat-list .ck svg { width: 12px; height: 12px; }

/* visual cards */
.vcard { background: var(--bg); border: 1px solid var(--line); border-radius: var(--r-xl); box-shadow: var(--sh-2); overflow: hidden; }
.vcard-top { padding: 16px 18px; border-bottom: 1px solid var(--line); display: flex; align-items: center; gap: 10px; }
.vcard-search { flex: 1; display: flex; align-items: center; gap: 10px; background: var(--bg-soft); border: 1px solid var(--line-2); border-radius: 12px; padding: 9px 14px; font-size: 14px; color: var(--ink-2); }
.vcard-search .mag { color: var(--ink-3); display: flex; }
.vcard-search .mag svg { width: 16px; height: 16px; }
.vcard-search .typed { color: var(--ink); }
.vcard-search .caret { width: 1.5px; height: 15px; background: var(--accent); animation: blink 1.1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

.imgrid { padding: 16px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.imgrid.q4 { grid-template-columns: repeat(2, 1fr); }
.ph-img {
  aspect-ratio: 4/3; border-radius: 12px; position: relative; overflow: hidden;
  background:
    repeating-linear-gradient(135deg, var(--bg-soft) 0 10px, var(--bg-sink) 10px 20px);
  border: 1px solid var(--line);
  display: flex; align-items: flex-end; padding: 9px;
}
.ph-img.tall { aspect-ratio: 3/4; }
.ph-img.has-img { background-size: cover; background-position: center; }

/* ---- animated (live) result tiles ---- */
.ph-img.live { padding: 0; }
.ph-img.live > .score { position: absolute; left: 9px; bottom: 9px; z-index: 6; }
.scene { position: absolute; inset: 0; overflow: hidden; }
.scene .sky { position: absolute; inset: 0; }
.scene .halo { position: absolute; border-radius: 50%;
  background: radial-gradient(circle, rgba(255,247,216,.95) 0%, rgba(255,170,74,.55) 45%, rgba(255,150,70,0) 72%);
  transform: translate(-50%,-50%); animation: sunPulse 5s ease-in-out infinite; }
.scene .disc { position: absolute; border-radius: 50%; transform: translate(-50%,-50%);
  box-shadow: 0 0 24px 6px rgba(255,190,90,.5); animation: sunPulse 5s ease-in-out infinite; }
.scene .sea { position: absolute; left: 0; right: 0; bottom: 0; }
.scene .shimmer { position: absolute; left: 0; right: 0; bottom: 0;
  background-image: repeating-linear-gradient(90deg, rgba(255,255,255,.14) 0 16px, rgba(255,255,255,0) 16px 34px);
  mix-blend-mode: overlay; opacity: .55; animation: shimmer 3.5s linear infinite; }
.scene .bird { position: absolute; color: #15100c; }
.scene .bird svg { display: block; }
.scene .flock { position: absolute; inset: 0; animation: flyAcross 11s linear infinite; }
.scene .flock.slow { animation-duration: 16s; animation-delay: -4s; }
.scene .cloud { position: absolute; height: 9px; border-radius: 999px;
  background: rgba(70,40,55,.5); filter: blur(2px); animation: cloudDrift 18s linear infinite; }
.scene .boat { position: absolute; color: #130e0a; animation: bob 4.5s ease-in-out infinite; }
.scene .palm { position: absolute; color: #120d09; transform-origin: bottom center; animation: sway 6s ease-in-out infinite; }
.scene .figure { position: absolute; color: #0f0b08; }
@keyframes sunPulse { 0%,100% { transform: translate(-50%,-50%) scale(1); opacity: 1; } 50% { transform: translate(-50%,-50%) scale(1.05); opacity: .9; } }
@keyframes shimmer { from { background-position: 0 0; } to { background-position: 50px 0; } }
@keyframes flyAcross { from { transform: translateX(-14%); } to { transform: translateX(114%); } }
@keyframes cloudDrift { from { transform: translateX(-50px); } to { transform: translateX(260px); } }
@keyframes bob { 0%,100% { transform: translateY(0) rotate(-1.5deg); } 50% { transform: translateY(-3px) rotate(1.5deg); } }
@keyframes sway { 0%,100% { transform: rotate(-2.5deg); } 50% { transform: rotate(2.5deg); } }
@media (prefers-reduced-motion: reduce) { .scene * { animation: none !important; } }
.ph-img .score { font-family: var(--font-display); font-size: 11px; font-weight: 600; color: var(--ink-2); background: color-mix(in srgb, var(--bg) 85%, transparent); border: 1px solid var(--line); padding: 2px 7px; border-radius: 999px; backdrop-filter: blur(4px); }
.ph-img.match { border-color: var(--accent); box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 22%, transparent); }
.ph-note { font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: 10.5px; color: var(--ink-3); }

/* drop / query image */
.querybox { display: flex; flex-direction: column; gap: 14px; }
.dropzone {
  border: 1.5px dashed var(--line-2); border-radius: var(--r-lg); padding: 22px;
  display: flex; align-items: center; gap: 16px; background: var(--bg-soft);
}
.dropzone .thumb { width: 72px; height: 72px; border-radius: 12px; flex: none;
  background: repeating-linear-gradient(135deg, var(--bg) 0 8px, var(--bg-sink) 8px 16px); border: 1px solid var(--line); }
.dropzone .dz-text { font-size: 14px; }
.dropzone .dz-text b { display: block; font-weight: 600; margin-bottom: 3px; }
.dropzone .dz-text span { color: var(--ink-3); font-family: ui-monospace, Menlo, monospace; font-size: 11px; }

/* ---------- privacy band ---------- */
.privacy .wrap { display: grid; grid-template-columns: 1fr; gap: 48px; }
.privacy-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 8px; }
.pcard { background: var(--bg); border: 1px solid var(--line); border-radius: var(--r-lg); padding: 30px 28px; }
.pcard .picon { width: 42px; height: 42px; border-radius: 12px; background: var(--bg-sink); color: var(--ink); display: flex; align-items: center; justify-content: center; margin-bottom: 20px; }
.pcard .picon svg { width: 21px; height: 21px; }
.pcard h3 { font-size: 18px; font-weight: 650; margin-bottom: 9px; letter-spacing: -.01em; }
.pcard p { font-size: 14.5px; color: var(--ink-2); }

.privacy-flow { display: flex; align-items: center; gap: 0; flex-wrap: wrap; justify-content: center; margin-top: 8px; }
.flow-node { display: flex; flex-direction: column; align-items: center; gap: 10px; text-align: center; min-width: 120px; }
.flow-node .fi { width: 56px; height: 56px; border-radius: 16px; border: 1px solid var(--line-2); display: flex; align-items: center; justify-content: center; color: var(--ink); background: var(--bg); }
.flow-node .fi svg { width: 24px; height: 24px; }
.flow-node span { font-size: 13.5px; color: var(--ink-2); font-weight: 500; }
.flow-arrow { color: var(--ink-3); padding: 0 6px; margin-bottom: 22px; }
.flow-arrow svg { width: 22px; height: 22px; }
.flow-shield { position: relative; }

/* ---------- formats ---------- */
.fmt-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(118px, 1fr)); gap: 12px; }
.fmt {
  border: 1px solid var(--line); border-radius: var(--r-md); padding: 16px 14px;
  background: var(--bg); transition: border-color .15s, transform .15s, box-shadow .15s;
}
.fmt:hover { border-color: var(--ink-3); transform: translateY(-2px); box-shadow: var(--sh-1); }
.fmt .ext { font-family: var(--font-display); font-weight: 700; font-size: 17px; letter-spacing: -.01em; }
.fmt .desc { font-size: 12px; color: var(--ink-3); margin-top: 4px; }

/* ---------- faq ---------- */
.faq-list { display: flex; flex-direction: column; border-top: 1px solid var(--line); max-width: 820px; }
.faq-item { border-bottom: 1px solid var(--line); }
.faq-q { width: 100%; background: none; border: none; cursor: pointer; text-align: left;
  display: flex; align-items: center; justify-content: space-between; gap: 20px;
  padding: 24px 4px; font-size: 18px; font-weight: 550; color: var(--ink); font-family: var(--font-body); }
.faq-q .pm { flex: none; width: 22px; height: 22px; position: relative; color: var(--ink-3); transition: transform .3s; }
.faq-q .pm::before, .faq-q .pm::after { content: ""; position: absolute; background: currentColor; border-radius: 2px; inset: 0; margin: auto; }
.faq-q .pm::before { width: 14px; height: 2px; }
.faq-q .pm::after { width: 2px; height: 14px; transition: transform .3s; }
.faq-item.open .pm::after { transform: rotate(90deg); opacity: 0; }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .35s ease; }
.faq-a p { padding: 0 4px 26px; font-size: 16px; color: var(--ink-2); max-width: 64ch; text-wrap: pretty; }

/* ---------- cta band ---------- */
.cta-final { text-align: center; }
.cta-final h2 { font-family: var(--font-display); font-size: clamp(30px, 4vw, 48px); font-weight: 700; letter-spacing: -.02em; line-height: 1.08; }
.cta-final p { font-size: 17px; color: var(--ink-2); margin: 18px auto 0; max-width: 40ch; }
.cta-final .hero-cta { margin-top: 34px; }

/* ---------- footer ---------- */
footer { border-top: 1px solid var(--line); padding: 56px 0 48px; background: var(--bg-soft); }
footer .wrap { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 40px; }
footer .fcol h4 { font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-3); margin-bottom: 16px; font-weight: 600; }
footer .fcol a { display: block; font-size: 14.5px; color: var(--ink-2); padding: 6px 0; transition: color .15s; }
footer .fcol a:hover { color: var(--ink); }
footer .fbrand p { font-size: 14px; color: var(--ink-2); margin-top: 14px; max-width: 30ch; }
footer .fbrand { display: flex; flex-direction: column; align-items: center; text-align: center; }
footer .fbrand .brand { flex-direction: column; gap: 12px; font-size: 22px; }
footer .fbrand .brand .mark { width: 52px; height: 52px; border-radius: 14px; }
.footer-bottom { border-top: 1px solid var(--line); margin-top: 44px; padding-top: 24px; }
.footer-bottom .wrap { display: flex; justify-content: space-between; align-items: center; font-size: 13px; color: var(--ink-3); }

/* reveal */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s cubic-bezier(.16,1,.3,1), transform .7s cubic-bezier(.16,1,.3,1); }
.reveal.in { opacity: 1; transform: none; }

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  :root { --pad: 22px; }
  [data-hero="split"] .hero .wrap { grid-template-columns: 1fr; gap: 40px; }
  [data-hero="split"] .hero { text-align: center; }
  [data-hero="split"] h1.hero-title, [data-hero="split"] .hero-sub { margin-left: auto; margin-right: auto; }
  [data-hero="split"] .hero-cta { justify-content: center; }
  .feature { grid-template-columns: 1fr; gap: 36px; }
  .feature.flip .feat-visual { order: 0; }
  .privacy-grid { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  footer .wrap { grid-template-columns: 1fr 1fr; gap: 32px; }
  section { padding: 64px 0; }
  .privacy-flow { gap: 4px; }
  .flow-node { min-width: 88px; }
}
@media (max-width: 560px) {
  .appwin-body { padding: 36px 20px; min-height: 280px; }
  .searchbar .ic { display: none; }
  .hero { padding: 56px 0 24px; }
  footer .wrap { grid-template-columns: 1fr 1fr; }
  .flow-arrow { transform: rotate(90deg); }
  .privacy-flow { flex-direction: column; }
  .flow-arrow { margin: 0; }
}