<p dir="auto">Why is that doubled?</p>
<p dir="auto">.container:before,<br>
.container:after {<br>
display: table;<br>
content: " ";<br>
}</p>
<p dir="auto">.container:after {<br>
clear: both;<br>
}</p>
<p dir="auto">.container:before,<br>
.container:after {<br>
display: table;<br>
content: " ";<br>
}</p>
<p dir="auto">.container:after {<br>
clear: both;<br>
}</p>
<p dir="auto">.row:before,<br>
.row:after {<br>
display: table;<br>
content: " ";<br>
}</p>
<p dir="auto">.row:after {<br>
clear: both;<br>
}</p>
<p dir="auto">.row:before,<br>
.row:after {<br>
display: table;<br>
content: " ";<br>
}</p>
<p dir="auto">.row:after {<br>
clear: both;<br>
}</p>
<p dir="auto">show on bootstrap.css</p>
<p dir="auto"><a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L581">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L581</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L723">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L723</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L743">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L743</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2023">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2023</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2433">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2433</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2617">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2617</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2637">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L2637</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3032">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3032</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3296">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3296</a><br>
<a href="https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3453">https://github.com/twbs/bootstrap/blob/3.0.0-wip/dist/css/bootstrap.css#L3453</a></p>