:root
{
        --GRAPH_CANVAS_WIDTH:1400;
        --GRAPH_CANVAS_HEIGHT:400;
}

#graph_canvas_id
{   
        position:absolute;    

        left:   calc(50% - ((var(--GRAPH_CANVAS_WIDTH) / 2) * 1px));
        top:    calc(20% - ((var(--GRAPH_CANVAS_HEIGHT) / 2) * 1px)); 

        width:  calc(var(--GRAPH_CANVAS_WIDTH) * 1px); 
        height: calc(var(--GRAPH_CANVAS_HEIGHT) * 1px);
}