css clearfix

метод 1

.container {
    box-sizing: border-box;
    display: inline-block;
    width: 100%;
    zoom: 1;
}

метод 2

.container:before,
.container:after {
    content: " ";
    display: table;
}
.container:after {
    clear: both;
}
.container {
    zoom: 1;
}

метод 3

.container {
    overflow: hidden;
    display: block;
    zoom: 1;
}