网页样式

参考：

• https://www.bilibili.com/video/BV1nM411T77W
• https://www.bilibili.com/video/BV1w84y1r7X8

todo 布局 https://www.bilibili.com/video/BV1am4y1E7DM/ https://www.bilibili.com/video/BV1EM411m71m/

todo 动画 https://www.bilibili.com/video/BV11X4y1V7ZZ https://www.bilibili.com/video/BV1Ki421S7WB 黑白切换⚪扩散