Sizing and aligning label issue

Hi all,

Currently I have a page as defined at http://pouxdagouti.org/aster/seeTechData.htm

And I try to align the labels squared as in the screenshot "Current situation" (see attached file labels2align.png).
I want to have something like defined in the screenshot "Goal" (see attached file labelsAligned.png).

I try the following code :

    #details-reseau label {
        width: 200px!important;
    }

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But it fails !

Thanks in advance for any advice.
labels2align.png
labelsAligned.png