You can edit the design of your forms to match the design of your website and keep everything looking uniform. You will be able to easily change the colour and opacity of the field background and field border, border width and radius, input text colour and button alignment in your design settings.
If you want to make changes on all the forms on your website, go to Change Design in the top right corner of your dashboard and go to the Form section.
If you want to customise a single form, go to stack-specific styling by hovering over the form you want to make the change on and clicking on the colour wheel.