.con3 {
    display: flex;
    width: 100%;
    gap: 5px;
}

.column {
    flex-grow: 1;
    /*background-color: #f0f0f0;*/
    padding: 0px;
    border: 1px solid #ccc;
    min-width: 1px;
    overflow: hidden;
    box-sizing: border-box;
}

#column1 
{
    width: 20%;
    background-color: #000000;
}

#column2 {
    width: 1px;
}

#column3 { 
    width: 80%;
}

.resizer {
    width: 5px;
    min-width: 5px;
    cursor: ew-resize;
    background-color: #ccc;
    position: relative;
}