html,body {
    box-sizing: border-box;
    overflow: hidden;
    height: 100%;
    max-height: 100%;
    margin: 0;
    padding: 0;
    font-family: tahoma;
    font-size: 14px;
}

body {
    padding-top: 2.5em;
    padding-bottom: 1.5em;
}

.headerBlock {
    box-sizing: border-box;
    position: absolute;
    top: 0;
    width: 100%;
    height: 2.5em;
    line-height: 2.5em;
    background: gainsboro;
    padding-right: 20em;
}

.headerBlock ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: block;
    width: 100%;
    overflow: hidden;
    line-height: 2.5em;
}

.headerBlock ul li {
    float: left;
    box-sizing: border-box;
    padding: 0 1.5em;
    border-left: 1px solid whitesmoke;
    border-bottom: 1px solid whitesmoke;
    cursor: pointer;
}

.IntroBlock {
    box-sizing: border-box;
    position: absolute;
    top: 0;
    right: 0;
    width: 20em;
    height: 100%;
}

.MainDesktop {
    box-sizing: border-box;
    height: 100%;
    max-height: 100%;
    overflow: hidden;
}


.window-footer {
    position: absolute;
    box-sizing: border-box;
    width: 100%;
    bottom: 0;
    left: 0;
    height: 1.5em;
    max-height: 1.5em;
    line-height: 1.5em;
    overflow: hidden;
    background: gainsboro;
    text-align: center;
}

.headerBlock ul li.active_component {
    border-bottom: 1px solid black;
}

.headerBlock ul li.active_component {
    color: #00acc8;
    background: #efeeee;
}