/* ===== 下载中心 前端样式（浅蓝渐变 · 高级简洁） ===== */
* { box-sizing: border-box; }
:root {
  --ink: #13243f;
  --ink-soft: #5b6781;
  --line: #eef2fb;
}

html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1100px 520px at 50% -8%, #e6f0ff 0%, rgba(230,240,255,0) 62%),
    radial-gradient(900px 480px at 100% 0%, #eafaf4 0%, rgba(234,250,244,0) 55%),
    linear-gradient(180deg, #f4f8ff 0%, #ffffff 38%, #f6faff 100%);
  background-attachment: fixed;
  min-height: 100vh;
}

/* Hero */
.hero {
  position: relative;
  padding: 96px 20px 74px;
  text-align: center;
  overflow: hidden;
}
.hero.has-bg { background-size: cover; background-position: center; background-repeat: no-repeat; }
.hero-mask { display: none; }
.hero.has-bg .hero-mask {
  display: block;
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(255,255,255,.45) 0%, rgba(255,255,255,.25) 100%);
  backdrop-filter: saturate(120%);
}
.hero-inner { position: relative; animation: fadeUp .6s both; }
.site-title {
  margin: 0;
  font-size: 44px;
  font-weight: 800;
  letter-spacing: 1px;
  color: var(--ink);
  text-shadow: 0 4px 24px rgba(255,255,255,.6);
}
.site-sub {
  margin: 14px 0 0;
  font-size: 17px;
  color: var(--ink-soft);
  letter-spacing: .3px;
}

/* Tabs */
.tabs {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  padding: 8px 16px 6px;
}
.tab {
  border: 1px solid #e3e9f6;
  background: rgba(255,255,255,.72);
  backdrop-filter: blur(8px);
  color: #46506a;
  padding: 11px 24px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all .2s;
  box-shadow: 0 4px 14px rgba(40,70,140,.04);
}
.tab:hover { border-color: var(--primary); color: var(--primary); transform: translateY(-1px); }
.tab.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  box-shadow: 0 8px 22px rgba(43,108,255,.28);
}

/* Container */
.container { max-width: 1100px; margin: 0 auto; padding: 24px 20px 70px; }
.product-panel { display: none; }
.product-panel.active { display: block; animation: fadeUp .4s both; }

.product-head { display: flex; align-items: center; gap: 16px; margin-bottom: 8px; }
.prod-icon {
  width: 64px; height: 64px; border-radius: 18px; object-fit: cover;
  box-shadow: 0 8px 22px rgba(20,30,60,.14);
}
.prod-name { margin: 0; font-size: 27px; font-weight: 700; letter-spacing: .5px; }
.prod-sub { margin: 5px 0 0; color: var(--ink-soft); font-size: 15px; }
.prod-desc { color: #5a6275; line-height: 1.8; margin: 12px 0 26px; max-width: 760px; }

/* Body layout */
.product-body {
  display: grid;
  grid-template-columns: 1fr 372px;
  gap: 30px;
  align-items: start;
}

/* Cards */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 18px; }
.empty { color: #9aa3b5; padding: 24px; }
.dl-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 20px;
  cursor: pointer;
  transition: transform .2s, box-shadow .2s, border-color .2s;
  box-shadow: 0 6px 20px rgba(40,70,140,.05);
  animation: fadeUp .45s both;
}
.dl-card:hover {
  border-color: var(--primary);
  transform: translateY(-3px);
  box-shadow: 0 16px 36px rgba(43,108,255,.14);
}
.dl-card.selected { border-color: var(--primary); box-shadow: 0 0 0 2px var(--primary) inset; }
.dl-top { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
.plat {
  color: #fff; font-size: 12px; font-weight: 600;
  padding: 4px 11px; border-radius: 999px; letter-spacing: .5px;
}
.ver { color: #8a93a6; font-size: 12px; }
.dl-name { font-size: 17px; font-weight: 600; margin-bottom: 16px; }
.dl-actions { display: flex; align-items: center; gap: 12px; }
.dl-btn {
  display: inline-block;
  background: var(--btn-color);
  color: #fff;
  text-decoration: none;
  padding: 11px 22px;
  border-radius: var(--btn-radius);
  font-size: 14px;
  font-weight: 600;
  transition: filter .15s, transform .15s;
}
.dl-btn:hover { filter: brightness(1.06); transform: translateY(-1px); }
.qr {
  width: 48px; height: 48px; border-radius: 10px; border: 1px solid var(--line);
  cursor: zoom-in; padding: 3px; background: #fff;
  box-shadow: 0 3px 10px rgba(40,70,140,.06);
}

/* Preview */
.preview {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 18px;
  position: sticky;
  top: 18px;
  box-shadow: 0 10px 30px rgba(40,70,140,.07);
  animation: fadeUp .5s both;
}
.preview img {
  width: 100%;
  border-radius: 14px;
  display: block;
  cursor: zoom-in;
  background: #f1f4fa;
  min-height: 220px;
  object-fit: cover;
}
.preview-tip { display: block; text-align: center; color: #aab2c4; font-size: 12px; margin-top: 12px; }

/* Footer */
.site-footer { text-align: center; color: #aab2c4; font-size: 13px; padding: 28px; }

/* Lightbox */
.lightbox {
  position: fixed; inset: 0;
  background: rgba(10,14,25,.82);
  display: none;
  align-items: center; justify-content: center;
  z-index: 999;
  padding: 30px;
}
.lightbox.show { display: flex; }
.lightbox img { max-width: 92vw; max-height: 88vh; border-radius: 12px; box-shadow: 0 20px 60px rgba(0,0,0,.5); }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: none; }
}

/* Responsive */
@media (max-width: 820px) {
  .product-body { grid-template-columns: 1fr; }
  .preview { position: static; order: -1; }
  .site-title { font-size: 32px; }
  .hero { padding: 70px 18px 54px; }
}