html {
    height: 100%;
}

body {
    height: 100%;
    overflow: hidden;  /*makes the body non-scrollable (we will add scrolling to the sidebar and main content containers)*/
    margin: 0px;  /*removes default style*/
    display: flex;  /*enables flex content for its children*/
    box-sizing: border-box;
}

.column {
    height: 100%;  /*allows both columns to span the full height of the browser window*/
    display: flex;
    flex-direction: column;  /*places the left and right headers above the bottom content*/
}

#left {
    flex-shrink: 0;  /*makes sure that content is not cut off in a smaller browser window*/
}

.top-left {
    background-image: url("LCol-BG.png");
    background-repeat: repeat-y;
    flex: none;
    width: 200px;
    height: 50px;
}

.top-right {
    background-image: url("LCol-BG.png");
    background-repeat: repeat-x;
    height: 50px;
    width: 800px;
    flex: none;
    display: inline-block;
}

ul {
    display: inline-flex;
    list-style: none;
}

.bottom-left {
    background-image: url("LCol-BG.png");
    background-repeat: repeat-y;
    flex-grow: 1;
    overflow-y: auto;  /*adds scroll to this container*/
}  

.bottom-right {
    flex-grow: 1;  /*ensures that the container will take up the full height of the parent container*/
    overflow-y: auto;  /*adds scroll to this container*/
}