html,
body { width: 100%; height: 100%; overflow: hidden; position: relative; background: url(images/bg.jpg) no-repeat center center #777; background-size: 100% 100%; background-attachment: fixed; margin: 0; padding: 0; }
body { min-height: 100%; background: transperent; }

.container { width: 70%; height: 50%; position: absolute; left: 0; right: 0; top: 0; bottom: 0; margin: auto; background-color: rgba(0,0,0,0.4); border: 2px solid rgba(255,255,255,0.5); box-shadow: 2px 2px 10px rgba(0,0,0,0.4); border-radius: 10px; overflow: hidden; }
.container .inner { width: 50%; height: 100%; }
.container .inner.left { float: left; }
.container .inner.rite { float: right; }
.container .inner .item { display: block; width: 100%; height: 50%; background-position: center center; background-repeat: no-repeat; background-size: 70% auto; transition: background 350ms ease-out; }
.container .inner .item:hover { background-color: rgba(0,0,0,0.4); }
.container .inner.left .item.top { background-image: url(images/logo-group.png); border-right: 1px solid rgba(255,255,255,0.5); border-bottom: 1px solid rgba(255,255,255,0.5); }
.container .inner.left .item.bot { background-image: url(images/logo-college.png); border-right: 1px solid rgba(255,255,255,0.5); border-top: 1px solid rgba(255,255,255,0.5); }
.container .inner.rite .item.top { background-image: url(images/logo-university.png); border-left: 1px solid rgba(255,255,255,0.5); border-bottom: 1px solid rgba(255,255,255,0.5); }
.container .inner.rite .item.bot { background-image: url(images/logo-school.png); border-left: 1px solid rgba(255,255,255,0.5); border-top: 1px solid rgba(255,255,255,0.5); }
.center-logo { width: 180px; height: 180px; position: absolute; left: 0; right: 0; top: 0; bottom: 0; margin: auto; z-index: 1000; }

@media (max-width:1199px) {
	.container { width: 80%; }
	.container .inner .item { background-size: 80% auto; }
	.center-logo { width: 140px; height: 140px; }
}
@media (max-width:992px) {
	.container { width: 90%; height: 50%; }
	.container .inner .item { background-size: 90% auto; }
	.center-logo { width: 120px; height: 120px; }
}