CSS not working

Hi

I am having trouble with my CSS in Tablepress.

My table has 3 columns. HOWEVER I want some of the rows to have 100% width because I only have info in the first out of the 3 columns. This is long text, and I do not want it to be placed over multiple lines, when it can be done with one.
Tablepress will not allow me to do this. When I use the code:

.tablepress-id-45 .column-1 {
width: 100%;
}

it works – HOWEVER then the rows below get pushed. I then added

.tablepress-id-45 th,
.tablepress-id-45 td {
width: 33%;
}

That did nothing until I removed the first code. I have also tried with the code:

.tablepress-id-45 .row-1 {
width: 100%;
}
where I write row instead of column – since it is the row and not the column, that I want to change. But nothing happens.

I have also tried to merge the cells. However, then I cannot use the DataTables JavaScript library, which I need, because the table is long, and it needs to be split up by using pagination.

So I am at a loss. The page is this: http://www.azitech.dk/events/hands-on-hdi-workshop/

You can see the problem under WORKSHOP OVERVIEW
I want the first line to be full width: During these two days, you will be exposed to a minimum of the following PCB Designer methodologies:

And the next rows to be 3 equal column spans. (All the grey should be with 100% width and the rest 3 equally spanned columns.)

How can I do this?? Please help 🙂

https://wordpress.org/plugins/tablepress/