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

body {
    /* 开启页面全局滚动 */
    overflow-y: auto;
    overflow-x: hidden;
    background: #f5f6f7;
}

/* ===================== */
/* 容器系统 */
/* ===================== */
.container {
    width: 1200px;
    margin: 0 auto;
}

/* ===================== */
/* 顶部 Header（固定） */
/* ===================== */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    height: 80px;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(10px);
    z-index: 1000;
}

.header-inner {
    height: 64px;
    display: flex;
    align-items: center;
    padding-top: 15px;
    padding-bottom: 10px;
}

/* Logo */
.logo {
    width: 250px;
    display: flex;
    align-items: center;
    margin-left: 20px;
    padding-top: 5px;
}

    .logo img {
        height: 64px;
    }

/* 搜索 */
.search {
    flex: 1;
    display: flex;
    justify-content: center;
}

.search-box {
    position: relative;
    width: 520px;
    margin-right: 10px;
}

    .search-box input {
        width: 100%;
        height: 38px;
        border-radius: 20px;
        border: none;
        padding: 0 40px 0 15px;
        outline: none;
        background: rgba(0, 0, 0, 0.04);
        box-shadow: inset 0 0 0 1px rgba(0,0,0,0.02);
        transition: all 0.25s ease;
    }

        .search-box input:focus {
            background: #fff;
            box-shadow: 0 2px 8px rgba(0,0,0,0.08), 0 0 0 2px rgba(0,170,255,0.08);
        }

.search-icon {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 14px;
}

/* 用户区 */
.user {
    width: 250px;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 10px;
}

.avatar {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: #ddd;
    overflow: hidden;
    margin-right: 30px;
}

    .avatar img {
        width: 100%;
        height: 100%;
        object-fit: cover;
        cursor: pointer;
    }

/* ===================== */
/* 主体布局（核心修改） */
/* ===================== */
.main {
    display: flex;
    width: 1200px;
    margin: 80px auto 0;
    /* 取消高度限制，让内容自动撑开 */
    height: auto;
    min-height: calc(100vh - 80px);
    position: relative;
}

/* 左侧侧边栏（固定） */
.sidebar {
    width: 200px;
    background: #fff;
    /* 固定定位，始终不动 */
    position: fixed;
    top: 80px;
    bottom: 0;
    left: calc(50% - 600px);
    z-index: 99;
    /* 取消自身滚动 */
    overflow-y: visible;
}

.menu-item {
    margin: 0px 10px 6px 10px;
    padding: 10px 14px;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    color: #333;
}

    .menu-item:hover {
        background: rgba(0, 0, 0, 0.04);
    }

    .menu-item.active {
        background: rgba(0, 170, 255, 0.12);
        color: #0095ff;
        font-weight: 600;
    }

/* 中间内容区 */
.content {
    flex: 1;
    /* 关键：左边空出侧边栏宽度 */
    margin-left: 200px;
    /* 右边空出右侧栏宽度 */
    margin-right: 280px;
    /* 取消自身滚动，使用页面全局滚动 */
    overflow-y: visible;
    background: #ffffff;
    padding-bottom: 30px;
}

/* tab 置顶固定 */
.tab {
    position: sticky;
    top: 80px;
    z-index: 10;
    background: #ffffff;
    padding: 3px 16px 10px;
}

    .tab span {
        position: relative;
        margin-right: 24px;
        padding-bottom: 5px;
        font-size: 16px;
        color: #666;
        cursor: pointer;
        transition: color 0.2s ease;
    }

        .tab span::after {
            content: "";
            position: absolute;
            left: 0;
            bottom: 0;
            width: 0;
            height: 5px;
            background: #00aaff;
            border-radius: 3px;
            transition: width 0.25s ease;
        }

        .tab span.active {
            color: #111;
        }

            .tab span.active::after {
                width: 100%;
            }

        .tab span.hover {
            color: #111;
        }

            .tab span.hover::after {
                width: 100%;
            }

/* 卡片流：取消自身滚动，全局滚动 */
.feed {
    padding: 10px 16px 16px 16px;
}

.card {
    background: #fff;
    padding: 16px;
    border-radius: 12px;
    margin-bottom: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    border: 1px solid #eee;
}

/* 右侧栏（固定） */
.aside {
    width: 280px;
    background: #fff;
    /* 固定定位，始终不动 */
    position: fixed;
    top: 80px;
    bottom: 0;
    right: calc(50% - 600px);
    z-index: 99;
    /* 取消自身滚动 */
    overflow-y: visible;
    padding: 0px 16px 16px 16px;
}

.side-card {
    background: #f5f6f7;
    border-radius: 12px;
    padding: 14px;
    margin-bottom: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    font-size: 13px;
}

.footer {
    padding-left: 5px;
    line-height: 25px;
    margin-top: 25px;
    font-size: 13px;
}