html - Bootstrap unwanted white space while display is mobile -

i using bootstrap website , came across odd white space can't seem rid of. if has encountered before happening on few devices iphone6, galaxy s4, galaxy note 3.

there margin: 0; padding: 0;, on <li>.

 <ul class="nav nav-justified">     <li class="active"><a href="#">home</a></li>     <li><a href="#">faq</a></li>     <li id="large"><a href="#" id="large" class="play">play</a></li>     <li><a href="#">promotions</a></li>     <li><a href="#">support</a></li>   </ul> 

heres image of mean white space.

this looks on devices:

in intial question, that's screenshot developer view yes?

i believe it's rendering fault when first switch mobile device mode.

i can replicate here, notice happens when switch iphone 6 preview , s4 (link), issue resolves itself. have done absolutely nothing css, merely refreshed view, im thinking must dev tools issue.

if wish 100% can run browsersync through nodejs locally , connect actual s4 or iphone , check that. or browserstack uses vm's of actual os's ensure accurate results possible.