It is best to use less clandestine CSS such as break-word, manual layering with z-index, vertical alignment, etc., because not all browsers may support it, and it is extremely difficult to pass W3C detection.
2. Center is not a float value.
Many novices will mistake center for the value of float, but it is not the case. center is just the value of text-align.
3. Alignment cannot include two values.
Many novices will fill in two values in float or text-align, such as: float:left top. This is not allowed and is not recognized by the browser.
4. It is best not to customize the color of the scroll bar.
Many browsers cannot properly recognize scroll bars with custom colors, and many custom colors cannot pass W3C.
5. Separate scroll bar settings.
Nowadays, overflow-x (horizontal scroll bar) or overflow-y (vertical scroll bar) are often used. When setting this, we often find that not all clients have the effect. It is best for everyone to set it up. Set both body and html at the same time. However, this CSS is not supported by CSS2.1 (CSS2.1 supports overflow and defines horizontal and vertical scroll bars). This definition method was not supported until CSS3. Use as little as possible.
6. If the background and color are the same, you will be warned.