*{
    margin:0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Poppins",sans-serif;
}
/* 删除原来的.container居中样式 */
nav{
    /* 关键：固定在浏览器右侧，上下居中 */
    position: fixed;
    top: 50%;
    right:20px; /* 距离右边20px */
    transform: translateY(-50%);
    border-radius: 30px 0 0 30px;/* 左边圆角，贴右屏幕 */
    padding:15px 8px;
    box-shadow: -5px 0 20px rgba(0,0,0,0.15);
    z-index:999;/* 防止被页面内容盖住 */
}
nav ul{
    display:flex;
    flex-direction:column;
}
nav ul li{
    list-style: none;
    padding: 14px 30px;
    margin:8px 0;
    font-size: 16px;
    font-weight: 500;
    color: #777;
    cursor: pointer;
    position: relative;
    z-index: 2;
    transition: color 0.5s;
    text-align:center;
}
nav ul li::after{
    content:"";
    background-color: #f44565;
    width: 100%;
    height: 100%;
    border-radius: 25px;
    position: absolute;
    top:100%;
    left: 50%;
    transform: translate(-50%,-50%);
    z-index: -1;
    opacity: 0;
    transition: top 0.5s,opacity 0.5s;
}
nav ul li:hover{
    color: #fff;
}
nav ul li:hover::after{
    top:50%;
    opacity: 1;
}
nav ul li a{
    color:inherit;
    text-decoration: none;
    display: block;
    width: 100%;
    height: 100%;
}
nav ul li.active{
    color: #fff;
}
nav ul li.active::after{
    top:50%;
    opacity:1;
}


.left-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 15vw;
    height: 100vh;
    background: transparent;
    transition: width 0.4s ease;
    z-index: 998;
    overflow: visible;
}
.left-sidebar.close {
    width: 60px;
}
/* 收缩时文字直接透明看不见 */
.left-sidebar.close li a {
    visibility: hidden;
}
.left-sidebar ul {
    list-style: none;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 80px;
    padding-left: 60px;
}
.left-sidebar ul li a {
    color: #fff;
    text-decoration: none;
    font-size: 22px;
    letter-spacing: 2px;
    transition: visibility 0.3s;
}
.left-sidebar ul li a:hover {
    color: #f44565;
}
.toggle-btn {
    position: absolute;
    top: 60px;
    right: -18px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: #f44565;
    color: #fff;
    border: none;
    cursor: pointer;
    z-index:999;
}