/* --- 1. 基础设置与文字放大 --- */
:root {
  --bg: #0b0c10;
  --card: #12141b;
  --text: #f3f5f7;
  --muted: #b9c0c9;
  --accent: #ff7a18;
  --whatsapp: #25D366;
  --border: rgba(255, 255, 255, .12);
}

* { box-sizing: border-box; }
body {
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  margin: 0;
  line-height: 1.6;
  font-size: 16px; /* 整体文字放大 */
}

.container { max-width: 1100px; margin: 0 auto; padding: 25px; }

/* --- 2. Header 与 语言按钮优化 --- */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 30px;
}

/* 强制锁定 Logo 大小，解决“巨大”问题 */
.brand img {
  height: 65px !important;
  width: auto !important;
  display: block;
}

.nav { display: flex; gap: 12px; }
.nav a {
  text-decoration: none;
  color: var(--muted);
  padding: 10px 18px; /* 增大按钮 */
  border: 1px solid var(--border);
  border-radius: 25px;
  font-size: 15px;
  background: rgba(255,255,255,0.05);
  transition: 0.3s;
}
.nav a.active {
  border-color: var(--accent);
  color: #fff;
  background: rgba(255, 122, 24, 0.15);
}

/* --- 3. PC端左右并排布局 (Hero区) --- */
.hero {
  display: grid;
  grid-template-columns: 1fr 1.2fr; /* 文字占45%，图片占55% */
  gap: 40px;
  background: var(--card);
  padding: 45px;
  border-radius: 24px;
  align-items: center;
  margin-bottom: 30px;
  border: 1px solid var(--border);
}

.hero h1 { font-size: 42px; margin: 0 0 15px 0; line-height: 1.2; }
.hero .small { font-size: 19px; color: var(--muted); margin-bottom: 25px; }

/* --- 4. 自行车图片显示优化 --- */
.product-main {
  background: #fff;
  border-radius: 16px;
  padding: 15px;
  display: flex;
  justify-content: center;
}

.product-main img {
  width: 100%;
  max-height: 500px; /* 限制 PC 端图片高度 */
  object-fit: contain;
  display: block;
}

.product-thumbs {
  display: flex;
  gap: 12px;
  margin-top: 15px;
  overflow-x: auto;
  padding-bottom: 8px;
}

.thumb img {
  width: 75px;
  height: 75px;
  object-fit: contain;
  background: #fff;
  border-radius: 10px;
  border: 2px solid transparent;
}

.thumb.is-active img { border-color: var(--accent); }

/* --- 5. 规格参数与联系方式 --- */
.grid { display: grid; grid-template-columns: 1.5fr 1fr; gap: 20px; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 20px; padding: 30px; }
.card h2 { font-size: 24px; margin-top: 0; }
ul li { margin-bottom: 12px; font-size: 16px; color: var(--muted); }

/* --- 6. 联系按钮 --- */
.cta { display: flex; gap: 15px; margin-top: 25px; }
.btn {
  flex: 1;
  text-align: center;
  text-decoration: none;
  padding: 15px;
  border-radius: 12px;
  font-weight: bold;
  font-size: 17px;
}
.btn-whatsapp { background: var(--whatsapp); color: #fff; }
.btn-call { border: 1px solid var(--accent); color: var(--accent); }

/* --- 7. 移动端自适应 (850px以下切换为单列) --- */
@media (max-width: 850px) {
  .hero { grid-template-columns: 1fr; text-align: center; padding: 25px; }
  .header { flex-direction: column; gap: 20px; }
  .grid { grid-template-columns: 1fr; }
  .nav { flex-wrap: wrap; justify-content: center; }
  .hero h1 { font-size: 32px; }
}