removing the color behind the module

How can I get rid of the white/gray color/area which is the background of the spotlight 1 position. I have to find the right css code but I can't find the right line. I wpuld like to have it like the other module area's on the website, so you can see the backround around the module. Hopefully sombody can help me ? Here you can see the example from which area I mean.

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Its about the website www.mattijs.net

Dear Mattijs,

Thanks for using our product,

Your question 1: Please go to .../templates/jux_galiana/local/css/themes/stbpb/template.css

find line 2329 and edit background as below:

.t3-sl-1 {

background: rgba(248, 245, 236, 0);

}