2/ Reduce space between the error message and previous field. Also make it in red (telling the user he has to fill the fields because it's obligatory).
3/ In my new Property Checkbox, reduce the space between question and the items.
I can't find where I can edit this CSS. I've checked the template files but it's not there 😕
Your styling would be in the stylesheet associated with the page. You can find what stylesheets are associated with the page by looking under "settings" in the landing page.