Through "php.cn Dugu Jiujian (2) - CSS video tutorial" you can learn: 1. What the hell is CSS? 2. Where is the most efficient place to write CSS? 3. The story of CSS selectors. 4. Style, what is the best? 5. Why does everyone like to use [class selector]? 6. Sentimental offspring selector, how can I save you? 7. A [pseudo-class] selector that resembles fog, rain, and wind. 8. A [universal] selector that would rather kill by mistake than let go. 9. The Dragon-Slaying Sword in the browser_a powerful CSS viewing and debugging tool. 10. Guide to avoid pitfalls_The mistakes we made together in those years~~