Knowledge points:
1. General pages without black, with light gray 3c3c3c
2.text-align: center; / * text is centered horizontally * /
3.font-weight: normal; / * Clear thickening effect * /
font-style: normal; / * Clear tilt effect * /
4. pseudo class selector
When hover hovering over XX elements: ××
See detailed code: https://github.com/superjishere/CSS_case