I initially had no understanding of CSS at all. However, through exploration and studying the CSS 2.0 manual, I gradually made changes by referring to templates and the manual until I achieved the effect I wanted. Unbeknownst to me, my CSS skills significantly improved in this process.
The electronic version of the CSS 2.0 manual is extremely comprehensive. When you encounter unfamiliar CSS properties, you can look up their usage and functions in the manual. Whether you're a beginner or an expert in CSS, I believe it's necessary to download this electronic manual. It will be a great help to you in template design.