*{box-sizing: border-box;}
div.wrapper{
    position:relative;
    margin: 0px auto;
    border: solid black 1px;
    width: 1000px;
    height: 800px;
}
div.header{
    position: absolute;
    top: 5px;
    left: 5px;
    right: 5px;
    height: 100px;
    border: solid green 1px;
}
div.horizNav{
    position: absolute;
    top: 5px;
    left: 5px; 
    right: 5px;
    height: 100px;
    border: solid blue 1px;
}
div.leftMenu{
    position: absolute;
    top: 165px;
    left: 5px;
    height: 630px;
    width: 300px;
    border: solid gray;
}
div.content{
    position: absolute;
    top: 165 px;
    left: 310px;
    right:5px;
    height: 630px;
    border: solid yellow 1px;
}