:root {
  color: #1b1d20;
  background: #f8fafc;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* { box-sizing: border-box; }
html { min-width: 320px; scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; min-height: 100vh; background: #f8fafc; }
a { color: inherit; text-decoration: none; }
button, a { -webkit-tap-highlight-color: transparent; }

.page-shell { position: relative; min-height: 100vh; overflow-x: hidden; background: #f8fafc; }
.page-background { position: absolute; inset: 42px 0 0; z-index: 0; pointer-events: none; background: url("/assets/h5-bg.png") center top / cover no-repeat; }
.site-header { position: fixed; inset: 0 0 auto; z-index: 10; height: 42px; display: flex; align-items: center; padding: 0 16px; background: rgba(255,255,255,.98); border-bottom: 1px solid #f1f5f9; box-shadow: 0 1px 3px rgba(0,0,0,.015); }
.brand { display: flex; align-items: center; gap: 7px; font-size: 15px; font-weight: 700; letter-spacing: .04em; }
.brand img { width: 26px; height: 26px; object-fit: contain; }

.hero { position: relative; z-index: 1; min-height: 802px; margin-top: 42px; padding: 288px 20px 30px; display: flex; flex-direction: column; align-items: center; }
.hero-content { width: 100%; max-width: 1152px; display: flex; flex-direction: column; align-items: center; }
h1 { display: flex; align-items: center; justify-content: center; gap: 0; margin: 0; color: #1b1d20; font-size: 23px; font-weight: 400; line-height: 1.3; letter-spacing: .04em; white-space: nowrap; }
h1 span { font-weight: 800; }
h1 i { margin: 0 8px; color: #1b1d20; font-size: 15px; font-style: normal; }
.tagline { width: 261px; margin: 12px 0 0; color: #606366; font-size: 13px; font-weight: 400; line-height: 1.6; letter-spacing: .03em; text-align: center; }
.tagline strong { color: #1b1d20; font-weight: 800; }
.tagline em { margin: 0 6px; color: #d0d3d6; font-style: normal; }

.download-grid { width: 100%; margin-top: 59px; display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; }
.platform-card { position: relative; width: min(100%, 297px); height: 54px; overflow: hidden; display: flex; align-items: center; justify-content: center; padding: 4px 16px; color: #fff; background: #24272c; border: 1px solid #383c44; border-radius: 14px; box-shadow: 0 4px 12px rgba(0,0,0,.15); transition: height .3s ease, background .3s ease, box-shadow .3s ease; }
.platform-card:hover { background: #2a2e34; }
.card-default, .card-hover { width: 100%; height: 100%; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 5px; text-align: center; }
.card-hover { position: absolute; inset: 0; opacity: 0; pointer-events: none; }
.platform-card small { color: #8e9299; font-size: 11px; line-height: 1; }
.platform-title { display: flex; align-items: center; gap: 10px; color: #fff; font-size: 16px; font-weight: 700; letter-spacing: .04em; line-height: 1; }
.platform-title img { width: 30px; height: 30px; object-fit: contain; }
.qr-code { width: 110px; height: 110px; padding: 8px; object-fit: contain; background: #fff; border-radius: 12px; }
.large-platform-icon { width: 80px; height: 80px; object-fit: contain; }
.card-hover b { font-size: 16px; letter-spacing: .04em; }
.mac-options { width: min(100%, 210px); display: flex; flex-direction: column; gap: 8px; }
.mac-options a { height: 60px; display: flex; align-items: center; justify-content: space-between; padding: 8px 16px; color: #1b1d20; background: #fff; border-radius: 16px; box-shadow: 0 2px 7px rgba(0,0,0,.12); font-size: 13px; font-weight: 700; }
.mac-options a > span:first-child { display: flex; align-items: center; gap: 8px; }
.apple-mark { display: inline-flex; width: 24px; height: 24px; align-items: center; justify-content: center; color: #1b1d20; font-size: 18px; }
.intel-mark { width: 24px; height: 24px; display: inline-flex; align-items: center; justify-content: center; color: #fff; background: #0071c5; border-radius: 50%; font-size: 8px; font-style: italic; }
.download-mark { color: #606366; font-size: 20px; line-height: 1; }
.mobile-guide { position: absolute; bottom: 29px; left: 50%; transform: translateX(-50%); color: #b5babf; font-size: 11px; font-weight: 700; letter-spacing: .04em; white-space: nowrap; }
.mobile-guide span { display: inline-block; margin-left: 4px; font-size: 17px; line-height: 10px; animation: bounce 1.4s ease-in-out infinite; }
.install-guide { min-height: 1180px; }

@media (min-width: 768px) {
  .page-background { inset: 84px 0 0; background-image: url("/assets/pc-bg.png"); background-size: cover; }
  .site-header { height: 84px; padding: 0 48px; }
  .brand { font-size: 20px; gap: 10px; }
  .brand img { width: 48px; height: 48px; }
  .hero { min-height: calc(100vh - 84px); margin-top: 84px; padding: 70px 24px 80px; justify-content: center; }
  h1 { font-size: 48px; }
  h1 i { margin: 0 14px; font-size: 28px; }
  .tagline { width: auto; margin-top: 16px; font-size: 18px; line-height: 1.5; }
  .download-grid { width: 100%; height: 192px; margin-top: 160px; flex-wrap: nowrap; align-items: flex-end; gap: 24px; }
  .platform-card { flex: 0 0 262px; height: 108px; border-radius: 20px; box-shadow: none; }
  .platform-card:hover { height: 192px; box-shadow: 0 16px 36px rgba(0,0,0,.3); }
  .platform-card:hover .card-default { opacity: 0; pointer-events: none; }
  .platform-card:hover .card-hover { opacity: 1; pointer-events: auto; }
  .platform-title { font-size: 19px; }
  .platform-title img { width: 46px; height: 46px; }
  .mobile-guide, .install-guide { display: none; }
}

@keyframes bounce { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(3px); } }

@media (max-width: 767px) {
  .mac-card { display: none; }
  .direct-card { display: none; }
  .download-grid { max-width: 297px; }
}

@media (min-width: 1024px) {
  .download-grid { max-width: 1112px; }
}