上篇:二、Flask学习之CSS
3.8hover
hover是用来美化鼠标悬停的效果的,当鼠标停放在某个区域,就会执行对应的hover操作。可以操作本标签的内容,也可以操作本标签下某一个标签的内容
3.9after
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>demo1</title><style>.name1:after{content: "潘达";}</style>
</head>
<body><div class="name1">panda</div><div class="name1">Hello</div>
</body>
</html>
after是用来在某个标签的最后添加某些东西:

3.10position
- fixed
- relative
- absolute
-  fixed(固定在窗口的某个位置) 案例: <!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><title>demo1</title><style>.back{position: fixed;height: 60px;width: 60px;border: 3px solid orange;bottom: 40px;/*距离底部40px*/right: 0;/*距离右部40px*/}</style> </head> <body><div class="back">panda</div> </body> </html>
-  relative和absolute 一个标签相对于另一个标签的位置 <!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><title>demo1</title><style>.name1{position: relative;height: 300px;width: 600px;border: 3px solid orange;top: 40px;left: 50px;}.name1 .name2{position: absolute;height: 30px;width: 60px;border: 3px solid blue;top: 40px;left: 50px;}</style> </head> <body><div class="name1"><div class="name2"></div></div> </body> </html>效果:  
3.11border
border是上下左右都加边框,board-left是左边框,board-right是右边框以此类推
 transparent是透明色