Logo does not appear on mobile

The Logo image for my site shows on desktop and ipad but doesn’t appear on mobile devices. My site is https://life11.org

Please tell me what changes should I make to the style.css code

I am pasting here the style.css code.

10.0 Content
————————————————————–*/
.site-branding {
width: 300px;
height: 106px;
padding: 20px 0 0;
}

#site-branding img{
margin:-120px 0 0 -100px;
}

.site-title {
line-height: 1; }

.site-title a {
color: #34495E; }
.site-title a:hover {
color: #3498db; }

.site-description {
font-size: 18px;
font-size: 1.8rem;
color: #6D6D6D; }

#site-navigation {
background-color: #34495E;
height: 57px; }