案例：html案例     状态：可编辑再运行    进入竖版
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<!DOCTYPE html>
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<html>
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​
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<head>
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  <title>Styling HTML5</title>
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  <!--[if lt IE 9]>
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  <script src="http://apps.bdimg.com/libs/html5shiv/3.7/html5shiv.min.js"></script>
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  <![endif]-->
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</head>
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​
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<body>
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​
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<h1>My First Article</h1>
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<article>
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London is the capital city of England.
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It is the most populous city in the United Kingdom,
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with a metropolitan area of over 13 million inhabitants.
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</article>
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​
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</body>
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</html>