:root {
  --navy: #06142c;
  --ink: #0d1b34;
  --blue: #176bff;
  --cyan: #14c9e7;
  --muted: #66758e;
  --line: #dce5f1;
  --surface: #f4f8fc;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: "Microsoft YaHei", "PingFang SC", Inter, Arial, sans-serif;
}
a { color: inherit; text-decoration: none; }

.nav {
  height: 76px;
  padding: 0 clamp(24px, 6vw, 96px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--navy);
  color: white;
  border-bottom: 1px solid rgba(255,255,255,.1);
  position: relative;
  z-index: 10;
}
.brand { display: flex; align-items: center; gap: 12px; font-weight: 800; letter-spacing: .04em; }
.brand-mark {
  width: 36px; height: 36px; display: grid; place-items: center;
  border-radius: 11px; color: white; font-style: italic;
  background: linear-gradient(135deg, var(--cyan), var(--blue));
  box-shadow: 0 8px 24px rgba(20,201,231,.3);
}
.nav-link { color: #c9d7eb; font-size: 14px; transition: .2s; }
.nav-link:hover { color: white; }

.hero {
  min-height: 620px;
  padding: 80px clamp(24px, 8vw, 132px);
  background:
    linear-gradient(rgba(255,255,255,.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.025) 1px, transparent 1px),
    radial-gradient(circle at 80% 35%, #103a72 0, transparent 36%),
    var(--navy);
  background-size: 44px 44px, 44px 44px, auto, auto;
  color: white;
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  align-items: center;
  gap: 60px;
  overflow: hidden;
  position: relative;
}
.glow { position: absolute; border-radius: 50%; filter: blur(80px); opacity: .3; }
.glow-one { width: 280px; height: 280px; background: #1676ff; right: 12%; top: 18%; }
.glow-two { width: 160px; height: 160px; background: #20d8d2; right: 38%; bottom: 0; }
.hero-copy, .hero-visual { position: relative; z-index: 2; }
.kicker { font-size: 12px; letter-spacing: .2em; font-weight: 800; color: #8ddaf0; text-transform: uppercase; }
.kicker span { display: inline-block; width: 28px; height: 2px; margin: 0 10px 3px 0; background: var(--cyan); }
.hero h1 { font-size: clamp(48px, 6vw, 82px); line-height: 1.08; letter-spacing: -.05em; margin: 22px 0; }
.hero h1 em { font-style: normal; color: transparent; -webkit-text-stroke: 1px #8fc9ff; }
.lead { max-width: 590px; font-size: 17px; line-height: 1.9; color: #adbed5; }
.hero-button {
  display: inline-flex; align-items: center; gap: 28px; margin-top: 28px;
  padding: 17px 22px; border-radius: 10px; font-weight: 800;
  background: linear-gradient(135deg, var(--blue), #1696e9);
  box-shadow: 0 14px 35px rgba(23,107,255,.32);
}
.hero-button span { font-size: 20px; }
.hero-visual { min-height: 410px; display: grid; place-items: center; }
.device-card {
  width: 245px; height: 330px; border-radius: 36px;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  background: linear-gradient(145deg, rgba(22,63,113,.92), rgba(5,21,47,.96));
  border: 1px solid rgba(100,193,255,.35);
  box-shadow: 0 35px 100px #020817, inset 0 1px rgba(255,255,255,.15);
  transform: rotate(5deg);
}
.device-card strong { margin-top: 32px; font-size: 20px; }
.device-card small { margin-top: 8px; color: #7eb6db; letter-spacing: .15em; }
.pulse-ring { width: 110px; height: 110px; border: 1px solid #25baff; border-radius: 50%; display: grid; place-items: center; box-shadow: 0 0 35px rgba(37,186,255,.3); }
.pulse-ring i { width: 46px; height: 46px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 32px var(--cyan); }
.orbit { position: absolute; border: 1px solid rgba(54,164,240,.2); border-radius: 50%; }
.orbit-one { width: 410px; height: 410px; }
.orbit-two { width: 520px; height: 260px; transform: rotate(-20deg); }
.float-tag { position: absolute; padding: 12px 15px; border-radius: 12px; background: rgba(9,31,62,.92); border: 1px solid rgba(106,183,236,.28); color: #cfeaff; font-size: 13px; box-shadow: 0 12px 30px #020a18; }
.float-tag b { color: #3ee2b2; margin-left: 8px; }
.tag-one { top: 18%; right: 2%; }
.tag-two { bottom: 18%; left: 2%; }

.download-section { padding: 100px clamp(24px, 7vw, 112px); background: var(--surface); }
.section-heading { max-width: 650px; margin-bottom: 48px; }
.kicker.dark { color: #2777b9; }
.section-heading h2, .instructions h2 { font-size: clamp(36px, 4vw, 56px); margin: 12px 0; letter-spacing: -.04em; }
.section-heading > p:last-child { color: var(--muted); line-height: 1.8; }
.download-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; max-width: 1400px; margin: auto; }
.download-card {
  background: white; padding: 28px; border-radius: 18px; border: 1px solid var(--line);
  box-shadow: 0 14px 34px rgba(24,51,91,.06); transition: transform .2s, box-shadow .2s;
}
.download-card:hover { transform: translateY(-5px); box-shadow: 0 22px 48px rgba(24,51,91,.12); }
.card-top { display: flex; align-items: center; justify-content: space-between; }
.platform-icon { width: 50px; height: 50px; display: grid; place-items: center; border-radius: 14px; color: white; font-size: 27px; background: var(--blue); }
.platform-icon.android { background: #19af77; font-size: 14px; }
.file-type { color: #789; background: #f0f4f8; border-radius: 7px; padding: 6px 8px; font: 700 11px monospace; text-transform: uppercase; }
.eyebrow { margin: 30px 0 8px; font-size: 11px; letter-spacing: .15em; text-transform: uppercase; color: #3f7fb7; font-weight: 800; }
.download-card h3 { margin: 0; font-size: 22px; }
.description { min-height: 52px; color: var(--muted); font-size: 14px; line-height: 1.7; }
.meta { display: flex; justify-content: space-between; padding: 18px 0; margin-top: 16px; border-top: 1px solid var(--line); color: #78879b; font-size: 12px; }
.download-button { display: flex; align-items: center; justify-content: center; gap: 10px; padding: 14px; border-radius: 9px; background: var(--ink); color: white; font-weight: 800; transition: .2s; }
.download-button:hover { background: var(--blue); }
.download-arrow { font-size: 18px; }
.download-card.green .platform-icon { background: #16ad76; }
.download-card.violet .platform-icon { background: #7565e9; }
.download-card.cyan .platform-icon { background: #159fd4; }

.instructions {
  padding: 90px clamp(24px, 8vw, 132px); display: grid; grid-template-columns: .7fr 1.3fr; gap: 70px;
  background: white;
}
.instructions ol { list-style: none; margin: 0; padding: 0; }
.instructions li { display: grid; grid-template-columns: 70px 1fr; gap: 15px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.instructions li b { color: #a9bad0; font-size: 24px; }
.instructions li span { color: var(--muted); line-height: 1.6; }
.instructions li strong { display: block; color: var(--ink); font-size: 18px; margin-bottom: 4px; }

footer { padding: 36px clamp(24px, 7vw, 112px); display: flex; align-items: center; justify-content: space-between; background: var(--navy); color: #8fa3bc; font-size: 12px; }
footer .brand { color: white; font-size: 14px; }
footer .brand-mark { width: 30px; height: 30px; border-radius: 9px; }

@media (max-width: 1050px) {
  .hero { grid-template-columns: 1fr; padding-top: 60px; }
  .hero-visual { min-height: 380px; }
  .download-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 680px) {
  .nav { height: 66px; }
  .hero { padding: 58px 24px; min-height: auto; }
  .hero h1 { font-size: 46px; }
  .hero-visual { min-height: 330px; transform: scale(.82); margin: -25px; }
  .download-section { padding: 70px 18px; }
  .download-grid { grid-template-columns: 1fr; }
  .instructions { grid-template-columns: 1fr; gap: 20px; padding: 70px 24px; }
  footer { flex-direction: column; gap: 18px; text-align: center; }
}

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