CSS基础
CSS 一切皆盒子 一、CSS的四种引入方式:行内嵌、嵌入式、链接式、导入式 <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <!-- 2.嵌入式 --> <style> /*选择标签*/ div{ /*属性名:属性值*/ color: red; background-color: green; } </style> <!-- 3.链接式 推荐使用 --> <link rel="stylesheet" type="text/css" href="css.css"> <!-- 4.导入式 --> <style> @import "css.css"; </style> </head> <body> <div> hello world </div> <!-- 1.行内嵌 --> <p style="color: red; background-color: palegreen"> Hello World</p> </body> </html> css.css文件 /*选择标签*/ div{ /*属性名:属性值*/ color: red; background-color: green; } 二、CSS选择器 1.基础选择器 <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> /*通用选择器*/ *{ font-size: 30px; } /*标签选择器*/ p{ background-color: green; } div{ color: blue; } /*ID选择器*/ #name{ color: red; font-style: italic; } /*class选择器*/ .cls1{ background-color: black; color: yellow; } </style> </head> <body> <p>hello</p> <div>world</div> <p id="name">名字</p> <p class="cls1">I love you</p> <div class="cls1"> I love Beijing</div> </body> </html> 2.组合选择器:后代选择器、子代选择器、变形选择器、毗邻选择器 <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> /*后代选择器*/ div p{ font-size: 35px; } div .cls1{ color: yellow; } #outer .cls2 .cls1{ color: blueviolet; } /*子代选择器*/ #outer>.cls1{ font-size: 50px; } /*变形选择器 */ #hello,.cls2{ font-style: italic; } /*毗邻 只更改下面紧挨的满足条件的标签*/ #outer+p{ color: aqua; } </style> </head> <body> <p id="hello">hello</p> <div id="outer">this is div <span>span</span> <p id="p1">this is p1</p> <p class="cls1">this is p2</p> <div class="cls2"> <p class="cls1">this is p3</p> </div> </div> <p>this is p4 </p> <p>this is p5 </p> </body> </html> 3.属性选择器 <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> /*属性标签*/ [class=div2]{ color: red; } /*E[attr~=val]*/ /*E[attr^=val]*/ /*E[sttr*=val]*/ p[class=div1]{ color: blueviolet; } </style> </head> <body> <div class="div1">div1</div> <p class="div1">div1</p> <div class="div2">div2</div> <div class="div3">div3</div> <div id="id">div4</div> </body> </html> 4.伪类 <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> a:link{ color: red; } a:hover{ color: yellow; } a:visited{ color: purple; } a:active{ color: blue; } p:after{ content: 'world'; } p:before{ content: "你好 世界"; color: green; } </style> </head> <body> <a href="https://www.baidu.com">百度一下</a> <p>hello </p> </body> </html 三、CSS的常用属性:1.颜色属性 2.字体属性 3.背景属性 4.文本属性 5.边框属性 <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> /**{*/ /*!*取消边距*!*/ /*margin: 0px;*/ /*}*/ /*颜色属性*/ p{ color: #ff0000; /*color: red;*/ /*color: rgb(255,0,0);*/ /*color:rgba(255,0,0,0.2);*/ } /*字体属性*/ p{ font-size: 30px; font-style: italic; font-family: "Times New Roman"; font-weight: bold; } /*背景属性*/ #div1{ height: 500px; width: 600px; background: url("timg.jpg") no-repeat darkseagreen center; } /*文本属性*/ p{ background-color: blueviolet; text-align: center; line-height: 100px; letter-spacing: 5px; word-spacing: 10px; text-transform: capitalize; } </style> </head> <body> <p>hello world</p> <div id="div1"></div> </body> </html> <!-- 内边距与外边距 --> <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <style> body{ border: solid 5px green; } .div1{ /*内边距*/ padding:50px; /*外边距*/ margin: 30px; /*边框*/ border: solid 30px red; height: 200px; width: 50%; background-color: blue; } </style> </head> <body> <div class="div1">div1</div> <div class="div2">div1</div> <div class="div3">div1</div> </body> </html>