一、这是多看榜单页面练习。使用了flex布局，二级菜单虽然完成，但结构复杂，希望尽快改正
二、二级菜单已改正
三、注意以下几点 1.:focus-within：当前元素或者当前元素的子元素处于focus状态时改变某些样式 例：在一个表单中，当某个文本输入框获取焦点时，整个表单的样式都被改变 不能随便的往某个元素添加这个样式，因为任意一个子元素变成焦点都会激活这个伪类的样式，:focus-within 应该被单独的用，而不是用在一个拥有很多可焦点化子元素的元素里。 2.标签内不要出现空属性 3.边线尽量用border-left/right，同时利用padding和margin来进行调控 4.类名是根据其功能描述，而不是状态 5.要使用line-height，尽量不要加在整体 6.熟练掌握flex布局 7.文字的省略问题（必须设置宽度） 8.样式继承，不要写冗余样式
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
Django
The Web framework for perfectionists with deadlines.
Laravel
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
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Facebook
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Microsoft
Open source projects and samples from Microsoft.
Google
Google ❤️ Open Source for everyone.
Alibaba
Alibaba Open Source for everyone
D3
Data-Driven Documents codes.
Tencent
China tencent open source team.
