Where can we change the user login input field background color.

This is a css style issue and it depends on your template. You should ask your template developer/provider in order to help you with this.

Hello,

thanks for your answer.

It seems to be a K2 CSS thing. On our template all input fields have a neutral background. Only the K2 user login shows a color. We want it to be neutral too.

We looked in the K2 CSS but didn't find the rule.

Where should we look?

Does your template have a k2.css file under the css folder with all other css files?
If yes, check in there. Otherwise provide me with a link to your site in order to check it out.

The site is worked on offline.

Can we give you any useful information otherwise?

Try to add the same background color in this class

div.k2LoginBlock fieldset.input p input {background-color:...;}