/* 头部导航样式 */
header {
    background: linear-gradient(135deg, #1e5799 0%, #2ec4b6 100%);
    color: white;
    padding: 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    width: 50px;
    height: 50px;
    background: rgba(255,255,255,0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    overflow: hidden;
}

.logo-icon img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

nav {
    display: flex;
    gap: 30px;
}

nav a {
    color: white;
    text-decoration: none;
    font-size: 14px;
    transition: opacity 0.3s;
}

nav a:hover {
    opacity: 0.8;
}