:root {
  --ink: #17362c;
  --muted: #64776e;
  --brand: #176b50;
  --brand-dark: #123d31;
  --line: #d5e1dc;
  --wash: #f3f7f5;
  --paper: #fff;
  --gold: #c58a26;
  --shadow: 0 16px 38px rgba(20, 57, 45, .10);
}

* { box-sizing: border-box; }

html { min-width: 320px; scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background: radial-gradient(circle at 90% 8%, rgba(31, 126, 91, .10), transparent 25rem), var(--wash);
  font: 16px/1.7 "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", system-ui, sans-serif;
}

.shell { width: min(1180px, calc(100% - 40px)); margin: 0 auto; }

.site-header {
  position: relative;
  overflow: hidden;
  padding: 28px 0 38px;
  border-bottom: 1px solid #cadad3;
  background: radial-gradient(circle at 86% 9%, rgba(23, 107, 80, .12), transparent 22rem), linear-gradient(135deg, #f8faf9, #edf4f0);
}

.site-header::after {
  position: absolute;
  right: -120px;
  bottom: -185px;
  width: 370px;
  height: 370px;
  border: 1px solid rgba(23, 107, 80, .11);
  border-radius: 50%;
  box-shadow: 0 0 0 44px rgba(23, 107, 80, .035), 0 0 0 94px rgba(23, 107, 80, .022);
  content: "";
}

.header-inner { position: relative; z-index: 1; text-align: center; }

.brand-lockup { display: flex; width: min(320px, 76vw); height: 46px; align-items: center; gap: 4px; }
.brand-lockup img { display: block; min-width: 0; max-height: 40px; object-fit: contain; object-position: left center; }
.brand-lockup img:first-child { width: 54%; }
.brand-lockup img:last-child { width: 40%; }

.eyebrow, .section-kicker { margin: 23px 0 5px; color: var(--brand); font-size: 12px; font-weight: 800; letter-spacing: .16em; }
.site-header h1 { margin: 0; color: var(--brand-dark); font-size: clamp(34px, 5vw, 56px); line-height: 1.16; letter-spacing: -.045em; }
.hero-copy { margin: 11px auto 0; max-width: 38rem; color: #a83a30; font-weight: 800; letter-spacing: .08em; }

.main-content, .chooser-content { padding: 40px 0 66px; }
.intro { margin-bottom: 24px; }
.intro h2, .chooser-panel h2 { margin: 0; color: var(--brand-dark); font-size: clamp(25px, 3.4vw, 34px); line-height: 1.25; }
.intro p:last-child, .chooser-panel > p { margin: 8px 0 0; color: var(--muted); }

.category-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
.category-card {
  display: block;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--paper);
  box-shadow: var(--shadow);
  color: inherit;
  text-decoration: none;
  transition: transform 170ms ease, box-shadow 170ms ease, border-color 170ms ease;
}
.category-card:hover { transform: translateY(-4px); border-color: #9cc8b6; box-shadow: 0 20px 44px rgba(20, 57, 45, .16); }
.category-card:focus-visible, .version-choice:focus-visible, .back-home:focus-visible { outline: 3px solid var(--gold); outline-offset: 4px; }
.category-card img { display: block; width: 100%; aspect-ratio: 900 / 500; object-fit: contain; background: #f7f7f7; }
.card-copy { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 15px 18px 17px; }
.card-copy strong { color: var(--brand-dark); font-size: 19px; }
.card-copy span { flex: none; color: var(--brand); font-size: 14px; font-weight: 800; }

.product-header { padding-bottom: 30px; }
.back-home {
  position: fixed;
  z-index: 40;
  top: 50%;
  right: 24px;
  transform: translateY(-50%);
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  border: 1px solid var(--brand);
  border-radius: 14px;
  background: var(--brand);
  padding: 10px 16px;
  box-shadow: 0 12px 26px rgba(18, 61, 49, .24);
  color: #fff;
  font-size: 16px;
  font-weight: 800;
  line-height: 1.35;
  text-decoration: none;
}
.back-home:hover { background: var(--brand-dark); }
.product-header .brand-lockup { margin: 0 auto; }
.product-header .eyebrow { margin-top: 16px; }
.chooser-content { display: grid; grid-template-columns: minmax(0, 1fr) minmax(330px, .88fr); align-items: center; gap: 36px; }
.product-cover { display: block; width: 100%; border: 1px solid var(--line); border-radius: 24px; background: var(--paper); box-shadow: var(--shadow); object-fit: contain; }
.chooser-panel { padding: 28px; border: 1px solid var(--line); border-radius: 22px; background: rgba(255, 255, 255, .86); box-shadow: var(--shadow); }
.chooser-panel .section-kicker { margin-top: 0; }
.version-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 24px; }
.version-choice { display: flex; min-height: 195px; flex-direction: column; justify-content: space-between; padding: 22px; border: 1px solid #b9d8ca; border-radius: 18px; background: #f0f8f4; color: var(--brand-dark); text-decoration: none; transition: transform 170ms ease, box-shadow 170ms ease; }
.version-choice:hover { transform: translateY(-3px); box-shadow: 0 12px 26px rgba(23, 107, 80, .14); }
.version-choice strong { font-size: 25px; }
.version-choice > span:last-child { font-size: 14px; font-weight: 800; }
.clinical-choice { border-color: #bed0e0; background: #f0f6fb; color: #24557b; }
.choice-label { font-size: 13px; font-weight: 800; letter-spacing: .06em; }

@media (max-width: 760px) {
  .shell { width: min(100% - 28px, 560px); }
  .site-header { padding: 22px 0 28px; }
  .brand-lockup { width: min(270px, 82vw); height: 40px; }
  .brand-lockup img { max-height: 34px; }
  .eyebrow { margin-top: 17px; letter-spacing: .12em; }
  .main-content, .chooser-content { padding: 28px 0 42px; }
  .category-grid, .chooser-content, .version-grid { grid-template-columns: 1fr; }
  .category-grid { gap: 16px; }
  .category-card { border-radius: 18px; }
  .card-copy { padding: 12px 14px 14px; }
  .card-copy strong { font-size: 17px; }
  .chooser-content { gap: 22px; }
  .chooser-panel { padding: 22px; }
  .version-choice { min-height: 150px; }
  .back-home { top: auto; right: 12px; bottom: 24px; transform: none; min-height: 44px; border-radius: 12px; padding: 9px 13px; font-size: 15px; }
}