Bootstrap is not working on mobile

i tried to run my design to the developer tools on chrome as a mobile but the bootstrap is not working. Can someone give me ideas why the bootstrap is not working on mobile?

here is the picture when i tried to run on mobile.

and this when i run on desktop it worked i don't know why not on mobile.

here is my media queries.

 @media (max-width: 768px) {
.img-responsive{
 width: 300px;
height:50px;
padding-left:50px;
}
}
@media (max-width: 376px) {
.img-responsive{
 width: 220px;
 height:50px;
 padding-left: 20px;
}
}
@media (max-width: 286px) {
.img-responsive{
 width: 180px;
 height:50px;
 padding-left: 5px;
 }
.footer{
 height: auto;
 }
 h4{
 padding-top: 50px;
 padding-left: 20px;
 }
 }

You are probably missing the viewport meta tag in the html head:

Viewport is the user's visible area of a web page. Using width=device-width you need to set the width to device width you are viewing in like mobile or tablet or desktop.

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

Refer this link : Viewport meta tag

What is Viewport?.