Dear blink black,
SJ Plus is responsive template, if you fix width, it maybe display wrong in other devices. If you want set with for content, please go to your_site/templates/sj_plus/css/template-blue.css and find:
#content #yt_component {
-moz-box-sizing: border-box;
background: none repeat scroll 0 0 #FFFFFF;
border: 1px solid #DDDDDD;
box-shadow: 0 0 3px rgba(0, 0, 0, 0.12);
clear: both;
margin-bottom: 30px;
margin-top: -1px;
min-height: 294px;
padding: 15px;
}
=>
#content #yt_component {
-moz-box-sizing: border-box;
background: none repeat scroll 0 0 #FFFFFF;
border: 1px solid #DDDDDD;
box-shadow: 0 0 3px rgba(0, 0, 0, 0.12);
clear: both;
margin-bottom: 30px;
margin-top: -1px;
min-height: 294px;
padding: 15px;
width: 800px;
}
Thanks