CSS Full width image - css

Question

I am developing a Wordpress site using a child theme and cornerstone page builder.
Cornerstone allows full width images with no containers for normal pages but not posts. How do I make the post include a full width image?
I want to make this: http://www.crestonsolutions.com/test-post/
Look like this: http://www.crestonsolutions.com/blog/how-to-keep-customers-coming-back-to-your-site/
Here is the CSS I've done to the site:
.x-navbar {
background-color: transparent !important;
border: 0;
}
.x-logobar{
background-color: transparent !important;
}
.masthead {
height:0px;
}
.x-nav-wrap.mobile {
background: rgba(17, 17, 17, 0.60);
margin: 0;
}
.x-btn-navbar.collapsed {
color: white;
}
#media (max-width: 979px){
.x-navbar-inner .x-container.max.width {
width: auto;
max-width: none;
}
.masthead-inline .x-btn-navbar {
margin-right: 15px;
}
.x-navbar .x-brand {
margin-left: 15px;
}
ul#menu-main-menu-1 {
width: 88%;
margin-left: auto;
margin-right: auto;
}
.x-navbar {
background-color: rgba(17, 17, 17, 0.60)!important;
position: fixed;
top: 0;
left: 0;
width: 100%;
}
.x-nav-wrap.mobile.collapse.in {
height: 100%;
position: fixed;
width: 100%;
top: 90px;
}
.x-navbar .x-nav-wrap .x-nav > li > a {
text-align: center;
font-size: 46px;
border: none;
margin-top: 0px;
margin-bottom: 0px;
padding-top: 0px;
padding-bottom: 0px;
}
}
hr.x-hr {
width: 20%;
border-top: 3px solid rgba(0,0,0,0.075);
margin: 0 auto;
}
.single-post .x-navbar {
color: black;
}
.single-post .entry-header {
display: none;
}
.single-post .site > .x-container-fluid {
max-width: 100% !important;
width: 100% !important;
}
.single-post .x-navbar a {
color: black;
}