Template:MainPageWelcomeCSS.css

.wiki-banner-wrapper {

 border: 2px solid #f79200;
 width: 100%;
 max-width: 100%;
 margin: 0 auto;
 overflow: hidden;
 padding: 0;
 box-sizing: border-box;

}

.wiki-banner-image img {

 width: 100%;
 height: auto;
 display: block;

}