/* ===== 顶部导航 ===== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 999;
    /* 只用天蓝色，从半透明 → 全透明，极致柔和 */
    background: linear-gradient(to bottom, rgba(255, 255, 255, 0), rgba(124, 203, 255, 0));
    height: 120px;
    padding: 18px 20px; /* 桌面端导航内边距 */
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: background 0.3s ease;
}

.nav > * {
    transform: translateY(-5px);
}

.nav.nav-solid {
    background: rgba(26, 131, 172, 0.9);
}

/* Logo 在弹性布局中保持稳定尺寸 */
.nav-logo {
    max-height: 44px;
    width: auto;
    margin-left: 0;
    flex-shrink: 0; /* 防止 Logo 被压缩 */
}

/* 桌面端菜单横向排列 */
.nav-menu {
    display: flex;
    gap: 35px;
    align-items: center;
    margin-left: auto;
    justify-content: flex-end;
    text-align: right;
}

/* 汉堡按钮默认隐藏，仅在移动端显示 */
.hamburger {
    display: none;
    width: 42px;
    height: 42px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.35);
    background: rgba(8, 45, 72, 0.28);
    color: #ffffff; /* 原#000000改为#ffffff */
    font-size: 18px;
    cursor: pointer;
    align-items: center;
    justify-content: center;
    line-height: 1;
    transition: background 0.25s ease, border-color 0.25s ease, transform 0.2s ease;
    position: relative;
    z-index: 1000;
    overflow: visible;
}

.hamburger:hover {
    background: rgba(8, 45, 72, 0.45);
    border-color: rgba(255, 255, 255, 0.65);
}

.hamburger:active {
    transform: scale(0.96);
    .hamburger-logo {width:32px; height:32px; object-fit:contain; display:block;}
}

/* 导航链接基础样式 */
.nav a {
    color: #e6e6e6;
    text-decoration: none;
    font-size: 15px;
    transition: all 0.3s;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.nav-link-svg {
    width: 16px;
    height: 16px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    opacity: 0.95;
}

.nav-link-svg svg {
    width: 100%;
    height: 100%;
}

.nav a:hover {
    color: #4fc3f7;
}

.dropdown {
    position: relative;
}

.dropdown-content {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: #195794c1;
    min-width: 160px;
    padding: 10px 0;
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    z-index: 1000;
}

.dropdown-content a {
    display: block;
    padding: 8px 20px;
    margin: 0;
    text-shadow: none;
}

.dropdown:hover .dropdown-content {
    display: block;
}