what is bootstrap
<div class="jumbotron text-center">
<h1>My First Bootstrap
Page</h1>
<p>Resize this page to see the responsive
effect!</p>
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<div class="container-fluid">
<div class="row">
<div class="col-sm-4">
<h2>London</h2>
<p>London is the capital city of England.</p>
<p>It is the most populous city in the United Kingdom,
with a
metropolitan area of over 13 million inhabitants.</p>
</div>
<div class="col-sm-4">
<h2>Paris</h2>
<p>Paris is
the capital of France.</p>
<p>The Paris area is one of the largest
population centers in Europe,
with more than 12 million
inhabitants.</p>
</div>
<div
class="col-sm-4">
<h2>Tokyo</h2>
<p>Tokyo is the capital of Japan.</p>
<p>It
is the center of the Greater Tokyo Area,
and the most populous
metropolitan area in the world.</p>
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</div>
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