这是用flex编写的简单导航栏

直接上代码吧

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>grid演示</title>
</head>
<body>
    <div class="content">
        <header>
            <nav>
                <a href="">首页</a>
                <a href="">视频</a>
                <a href="">社区</a>
                <a href="">文章</a>
                <a href="">咨询</a>
                <a href="">简介</a>
                <a href="">源码</a>
                <a href="">作业</a>
                <a href="">下载</a>
            </nav>
            <button>登陆</button>
        </header>
    </div>
    <footer class="footer">页脚</footer>
    <style>
        .box {
    width: 100%;
    height: 2000px;
}
header {
    height: 80px;
    background-color: rgb(248, 244, 244);
    padding: 0 5em;
    display: flex;
    place-content: space-between;
    position: sticky;
    top: 0;
    color: #0c0202;
}
nav {
    display: flex;
    /* 水平垂直居中 */
    text-align: center;
    line-height: 80px;
}
nav a {
    min-width: 5em;
    color: #0c0505;
    text-decoration: none;
    flex: 1;
}
nav a:hover {
    color: white;
    background-color: aqua;
    transition: 0.3s;
}
header button {
    border: none;
    width: 5em;
    background-color: rgb(3, 5, 4);
    color: azure;
}
header button:hover {
    cursor: pointer;
    background-color: rgb(22, 228, 228);
}
footer {
    width: 100%;
    height: 50px;
    color: #ccc;
    background-color: black;
    text-align: center;
    line-height: 50px;
}
.box .title {
    height: 50px;
    font-weight: bolder;
    border: 1px solid #f5f1f1;
    background-color: rgb(10, 10, 10);
}
.box .content {
    min-width: 100%;
    min-height: 0px;
    background-color: #eee;
}
.box .title {
    /* 滚动到top=0就会自动停止并固定在当前位置 */
    position: sticky;
    top: 0;
    color: #9b9292;
    line-height: 50px;
    padding: 0 20em;
}
.box1 {
    width: 100px;
    height: 500px;
    display: flex;
    border: 1px solid #e0e4de6b;
    place-content: space-evenly;
    flex-flow: column nowrap;
    position: fixed;
    top: 5cm;
    bottom: 0;
    /* line-height: 50px; */
    border-radius: 20px 20px 20px 20px;
}
.box1 a {
    width: 100%;
    height: 25px;
    letter-spacing: 2px;
    text-align: center;
    text-decoration: none;
    color: #9b9292;
    /* flex: 1 1 auto; */
}
.box1 a:hover  {
    color: white;
    background-color: rgb(70, 184, 159);
    transition: 0.1s;
}
        </style>
</body>
</html>