.container {
    border: 1px solid red;
    overflow: hidden;
}

ul.slider {
    list-style: none;
    padding: 0;
    margin: 0;
    white-space: nowrap;
    width: 100%;
    overflow: auto;
    margin-bottom: -30px;
    padding-bottom: 30px;
}

.slider span {
    list-style: none;
    padding: 0;
    margin: 0;
    overflow: auto;
    white-space: nowrap;
    width: 50%;
    display: inline-block;
    padding: 20px;
}

.slider span li {
    display: inline-block;
    width: 100%;
    height: 300px;
    background-color: #333;
}