OOCSS - My Top 5 Most Reused

.fullscreen {
width:100%;
height:100%;
position:absolute;
top:0;
left:0;
}

.fillspace {
width:100%;
height:100%;
}

.bbox {
-webkit-box-sizing:border-box;
-moz-box-sizing:border-box;
-ms-box-sizing:border-box;
box-sizing:border-box;
}

.ellipsis-text {
white-space:nowrap;
overflow:hidden;
text-overflow:ellipsis;
}

.theme-bg {
background-color:cyan;
}