background grid assistance required

i spent countless hours researching how to do this but i still can’t wrap my head around it. in plain old css, i simply need a 1px dot pattern with 3px of space between each dot as a div background. i can create a straight dotted line in any direction (hooray!) but for the life of me i simply cannot create the dotted grid pattern. im not looking to do it as an svg or an image, and i am not looking for a radial pattern, i just need a clean and simple 1px x 1px square dot. i also don't need it with any vendor prefixes. any assistance would be greatly greatly appreciated. THANK YOU!