/* =========================
   HEADER 基础（半透明白字）
========================= */
.header{
  position:fixed;
  top:0;
  width:100%;
  z-index:1000;
  padding-top:60px;
  background: rgba(255,255,255,0.15);
  backdrop-filter: blur(10px);
  color: #fff;
  transition: all 0.4s ease;
}

/* =========================
   容器（关键：防止跑版）
========================= */
.header-inner{
    max-width:1400px;
    margin:0 auto;

    display:flex;
    justify-content:space-between;
    align-items:center;

    padding:25px 60px;
    position:relative;
}



/* 左右导航 */
.nav-left,
.nav-right {
  display: flex;
  gap: 30px;
  align-items: center;
}

.nav-left a,
.nav-right a {
  text-decoration: none;
  color: #333;
  font-size: 14px;
}


/* logo 居中 */
.logo{
  position:absolute;
  left:50%;
  transform:translateX(-50%);
  font-weight:600;
  letter-spacing:3px;
  white-space:nowrap;
  text-decoration:none;
  color:inherit;
}


/* =========================
   链接
========================= */
.header a{
    text-decoration:none;
    color:inherit;
    position:relative;
}

/* =========================
   👉 Hover：白底 + 黑字（你要的）
========================= */
.header:hover{
    background:#f5f5f5;
    color:#111;
}

/* =========================
   滚动状态
========================= */
.header.scrolled{
    background:#fff;
    color:#111;
    border-bottom:1px solid rgba(0,0,0,0.08);
}

/* =========================
   Dropdown
========================= */
.nav-item{
    position:relative;
}

.dropdown{
    position:absolute;
    top:30px;
    left:0;

    display:flex;
    flex-direction:column;
    gap:12px;

    padding:15px 0;

    opacity:0;
    visibility:hidden;
    transform:translateY(10px);

    transition:all 0.3s ease;
    background-color: #f5f5f5; /* ⭐ 新增：下拉菜单背景色 */
    border-radius: 0px; /* 可选：圆角效果 */
    box-shadow: 0 5px 20px rgba(0,0,0,0.1); /* 可选：阴影 */
}

.nav-item:hover .dropdown{
    opacity:1;
    visibility:visible;
    transform:translateY(0);
}

/* dropdown 链接 */
.dropdown a{
    font-size:13px;
    opacity:0.7;
    transition:0.3s;
}

.dropdown a:hover{
    opacity:1;
}

/* =========================
   下划线动效（高级感）
========================= */
.header a::after{
    content:'';
    position:absolute;
    left:0;
    bottom:-4px;

    width:0;
    height:1px;

    background:currentColor;
    transition:0.3s;
}

.header a:hover::after{
    width:100%;
}