/* ============================================================
   Dual 帝而 国际智享电器 官网 — 仿 www.dualchina.cn 样式
   ============================================================ */
:root {
  --contrast: #111111;
  --contrast-2: #636363;
  --base: #f9f9f9;
  --white: #ffffff;
  --accent: #d8613c;   /* 品牌红 */
  --font-body: "Inter", "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
  --nav-h: 84px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--white);
  color: var(--contrast);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a { text-decoration: none; color: inherit; }

/* ---------------- 顶部导航（黑色，固定） ---------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--contrast);
  color: var(--white);
}

.header-inner {
  max-width: 1600px;
  margin: 0 auto;
  padding: 0 48px;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}

.brand img { width: 52px; height: auto; }

.brand-name {
  font-size: 26px;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--white);
}

.main-nav ul {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 34px;
}

.main-nav a {
  font-size: 16px;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.88);
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: color .2s, border-color .2s;
}

.main-nav a:hover { color: var(--white); border-bottom-color: var(--accent); }

.main-nav a.active { color: var(--white); border-bottom-color: var(--accent); }

.header-search {
  display: flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.10);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 6px;
  padding: 0 8px;
  height: 38px;
  width: 220px;
  flex-shrink: 0;
}

.header-search input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--white);
  font-size: 14px;
  padding: 0 4px;
}

.header-search input::placeholder { color: rgba(255, 255, 255, 0.55); }

.header-search button {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--white);
  display: flex;
  align-items: center;
  padding: 4px;
}

/* 移动端菜单按钮 */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  color: var(--white);
}

/* ---------------- 主内容：全宽大图通栏 ---------------- */
.site-main .banner-img,
.site-main .hero-img {
  width: 100%;
}

/* 轮播 */
.slider {
  position: relative;
  width: 100%;
  overflow: hidden;
  background: #000;
}

.slider-track {
  display: flex;
  transition: transform .7s ease;
}

.slider-slide {
  min-width: 100%;
  position: relative;
}

.slider-slide img {
  width: 100%;
  height: auto;
}

.slider-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: rgba(0, 0, 0, 0.35);
  color: #fff;
  font-size: 20px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 5;
  opacity: .8;
  transition: opacity .2s, background .2s;
}

.slider-arrow:hover { opacity: 1; background: rgba(0, 0, 0, 0.6); }

.slider-arrow.prev { left: 16px; }
.slider-arrow.next { right: 16px; }

.slider-dots {
  position: absolute;
  bottom: 18px;
  left: 0;
  right: 0;
  display: flex;
  justify-content: center;
  gap: 10px;
  z-index: 5;
}

.slider-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.5);
  cursor: pointer;
  transition: background .2s, transform .2s;
}

.slider-dots span.active { background: #fff; transform: scale(1.2); }

/* 通栏大图 */
.full-img {
  width: 100%;
  overflow: hidden;
}

.full-img img { width: 100%; height: auto; }

/* 底部备案条 */
.site-footer {
  width: 100%;
}

.site-footer img { width: 100%; height: auto; }

/* ---------------- 响应式 ---------------- */
@media (max-width: 1100px) {
  .header-search { width: 170px; }
  .main-nav ul { gap: 22px; }
}

@media (max-width: 900px) {
  .header-inner { padding: 0 20px; height: 64px; }
  .brand-name { font-size: 20px; }
  .brand img { width: 42px; }

  .nav-toggle { display: flex; }

  .header-search { display: none; }

  .main-nav {
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--contrast);
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    transform: translateY(-120%);
    transition: transform .3s ease;
    z-index: 99;
  }

  .main-nav.open { transform: translateY(0); }

  .main-nav ul {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 20px 16px;
  }

  .main-nav li { border-bottom: 1px solid rgba(255, 255, 255, 0.08); }

  .main-nav a { display: block; padding: 14px 4px; }

  .slider-arrow { width: 38px; height: 38px; font-size: 16px; }
}