.colmid {
    float:left;
    width:200%;
    margin-left:-12em;      /* Width of right column */
    position:relative;
    right:100%;
}
.colleft {
    float:left;
    width:100%;
    margin-left:-50%;
    position:relative;
    left:24em;              /* Left column width + right column width */
}
.col1wrap {
    float:left;
    width:50%;
    position:relative;
    right:10em;             /* Width of left column */
}
.grosses_bild {
    margin:0 10em 0 10em;
    position:relative;
    left:200%;
}
.col1 {
    margin:8 15em 8 11em;   /* Centre column side padding:
                            Left padding = left column width + centre column left padding width
                            Right padding = right column width + centre column right padding width */
    position:relative;
    left:200%;
    overflow:hidden;
}
.col2 {
    float:left;
    float:right;            /* This overrides the float:left above */
    width:10em;              /* Width of left column content (left column width minus left and right padding) */
    position:relative;
    right:1em;              /* Width of the left-hand side padding on the left column */
}
.col3 {
    float:left;
    float:right;            /* This overrides the float:left above */
    width:10em;             /* Width of right column content (right column width minus left and right padding) */
    margin-right:3em;       /* Width of right column right-hand padding + left column left and right padding */
    position:relative;
    left:50%;
}