语义化标签的布局通过语义化标签和 float 实现以下的布局： HTML 部分 CSS 部分,这是 HTML5 新增标签

通过语义化标签和 float 实现以下的布局：

HTML 部分

<!DOCTYPE html>
<html lang="en">
<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">
    <link rel="stylesheet" href="demo.css">
    <title>Demo</title>
</head>
<body>
    <div class="contaniner">
        <header>公司 LOGO</header>
        <nav>
            <ul>
                <li>首页</li>
                <li>学习</li>
                <li>视频</li>
                <li>关于我</li>
            </ul>
        </nav>
        <article class="article-main">
            <article>文章内容2
                <section>2-1</section>
                <section>2-2</section>
            </article> 
            <aside>侧边栏</aside>
        </article>
        <footer>页尾</footer>
    </div>
</body>
</html>

CSS 部分

.contaniner {
    max-width: 700px;
    position: relative;
    outline: 1px red solid;
    margin: 0 auto;
}

header {
    height: 30px;
    background-color: azure;
}

nav {
    height: 60px;
    background-color: aquamarine;
}

nav ul{
    margin: 0;
    list-style-type: none;
    padding-left: 0;
}

nav li {
    display: inline-block;
}

.article-main {
    float: left;
}

.article-main article{
    height: 300px;
    width: 500px;
    float: left;
    background-color: lightsalmon;
}

.article-main article section {
    margin-left: 30px;
}

aside {
    float: right;
    width: 200px;
    height: 300px;
    background-color: lightpink;
}

footer {
    width: 700px;
    background-color: gray;
    height: 60px;
    clear: both;
}