:root {
  --bg: #ffffff;
  --text: #16212c;
  --muted: #5e6c78;
  --line: #dde5ea;
  --brand: #0b6b4f;
  --brand-dark: #074a37;
  --card: #f6f9fa;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  background: var(--bg);
  font-family: "Segoe UI", "Microsoft YaHei", system-ui, sans-serif;
  line-height: 1.6;
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px 24px;
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
}

.brand {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--brand-dark);
}

.main-nav,
.lang-switch {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.main-nav a,
.lang-switch a {
  font-weight: 600;
  white-space: nowrap;
}

.main-nav a {
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--brand-dark);
  padding: 5px 0;
  position: relative;
}

.main-nav a:hover {
  color: var(--brand);
  text-decoration: none;
}

.main-nav a:hover::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--brand);
}

.lang-switch a {
  color: var(--muted);
}

.container {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.hero {
  padding: 54px 0 40px;
  border-bottom: 1px solid var(--line);
}

.hero p {
  font-size: 1.08rem;
  max-width: 820px;
}

.products-section {
  padding: 46px 0 64px;
}

.products-section h2 {
  margin-top: 0;
}

.product-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.product-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--card);
  color: inherit;
}

.product-card:hover {
  border-color: var(--brand);
  text-decoration: none;
}

.product-card img {
  width: 80%;
  margin: 12px auto 0;
  aspect-ratio: 4 / 3;
  object-fit: contain;
  background: #fff;
}

.product-card-body {
  padding: 18px;
}

.product-card-body h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.product-card-body h3 a {
  color: inherit;
  text-decoration: none;
}

.product-card-body h3 a:hover {
  color: var(--brand);
}

.product-card-body p {
  margin: 0;
  color: var(--muted);
}

.card-buy {
  display: inline-block;
  margin-top: 14px;
  padding: 8px 14px;
  font-size: 0.95rem;
}

.product-detail {
  padding: 48px 0 64px;
}

.product-detail h1 {
  margin-top: 0;
}

.lead {
  font-size: 1.1rem;
  color: var(--muted);
}

.buy-button {
  display: inline-block;
  margin: 10px 0 4px;
  padding: 12px 18px;
  border-radius: 10px;
  background: var(--brand);
  color: #fff;
  font-weight: 700;
}

.buy-button:hover {
  background: var(--brand-dark);
  color: #fff;
  text-decoration: none;
}

.product-main-image {
  border-radius: 16px;
  margin: 28px 0;
}

.product-point {
  margin: 28px 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
}

.product-point h2 {
  margin-top: 0;
  font-size: 1.18rem;
}

.product-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 28px;
}

.product-gallery img {
  border-radius: 14px;
  border: 1px solid var(--line);
  background: #fff;
}

.page {
  padding: 48px 0 64px;
  max-width: 860px;
}

.download-list {
  display: grid;
  gap: 14px;
  margin-top: 28px;
}

.download-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--card);
  color: inherit;
}

.download-item:hover {
  border-color: var(--brand);
  text-decoration: none;
}

.contact-email a {
  font-size: 1.2rem;
  font-weight: 700;
}

.site-footer {
  padding: 24px;
  border-top: 1px solid var(--line);
  text-align: center;
  color: var(--muted);
}

.site-footer p {
  margin: 6px 0;
}

@media (max-width: 640px) {
  .site-header {
    align-items: flex-start;
  }

  .hero {
    padding: 36px 0 28px;
  }

  .products-section,
  .product-detail,
  .page {
    padding-top: 32px;
    padding-bottom: 42px;
  }
}