批改状态:合格
老师批语:应该配图会好一些
em
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><link rel="stylesheet" href="css01.css"></head><body><h2>php.cm</h2><div></div></body></html>
html {/* 1em=px */font-size: 20px;}body div:first-of-type{font-size: 1em;width: 100px;height: 100px;background-color: aqua;}
在hetmlfont-size=20px,1em变成20px可以全局作用,具有继承性
html {/* 1em=px */font-size: 20px;}body div:first-of-type{font-size: 1em;width: 100px;height: 100px;background-color: aqua;}
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><link rel="stylesheet" href="css01.css"></head><body><button class="btn small">按钮</button><button class="btn normal">按钮</button><button class="btn larger ">按钮</button></body></html>
.btn {background-color: antiquewhite;color: aqua;border:none;outline: none;padding: 0.5em 1em;border: 0.3em;}.btn:hover{opacity: 0.5;cursor: pointer;box-shadow: 0 0 3px cornflowerblue;transition: 0.3s;}.small {font-size: 10px;}.normal {font-size: 16px;}.larger {font-size: 22px;}
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><link rel="stylesheet" href="css01.css"></head><body><div class="pa"><h2>我</h2><div class="papa"><p>你</p></div></div></body></html>
html {/* 16/0.8=12.8px=0.8em *//* 定义 */font-size: 0.8em;}.pa {/* 默认是1rem */font-size: 2rem;}.pa p {font-size: 4rem;}
vw占屏幕宽的1/100
vh占屏幕高的1/100
应用于移动端布局,手机屏幕随尺寸改变改变
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><link rel="stylesheet" href="css01.css"></head><body><div class="box"></div></body></html>
.box {width: 50vw;height: 80vh;background-color: crimson;margin: auto ;}
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