Twitter bootstrap not working properly in safari 5.1.7

Am using below Twitter Bootstrap cnd it is working well with Firefox ,chrome and IE browsers but problem with Safari 5.1.7 browser as well as Iphone 6.

<link rel="stylesheet" href="http://ift.tt/1K1B2rp">
<link rel="stylesheet" href="http://ift.tt/1QMqYrP">
<script src="http://ift.tt/1InYcE4"></script>

Also added

 <meta name="viewport" content="width=device-width, initial-scale=1">

But not working well in Safari Browser .

hope for the best.

via Chebli Mohamed