div.header {
    width: 100%;
    height: 200px;
    border: 1px solid black;
}

div.content{
    padding: 5px;
    float: right;
    width: 72%;
    height: 650px;
    display: inline-block;
    border: 1px solid black;
}

div.leftblock {
    display: inline-block;
    float: left;
    width: 25%;
    height: 650px;
    margin-right: 5px;
    border: 1px solid black;
    padding: 5px;
}

div.footer {
    display: inline-block;
    width: 100%;
    height: 100px;
    border: 1px solid black;
}

ul li {
    display: inline-block;
    margin-right: 5px;
    border-right: 1px solid black;
    padding: 5px;
    transition: 1s;
}

ul li:hover {
    background: red;
}