How to Customize Checkbox Using CSS?

Hi friends , Being a developer I am learning html, CSS, php & web Development. I am here to enhance my learning on web development through various forums like html developer forum and other web developer communities & want to customize checkbox with the help of CSS. Mostly developers use javascript for customizing the look of the checkboxes but I want to use CSS. I hope any tech developer can help me over here in resolving the issue.