CSS3 box-shadow 属性用来描述一个元素的一个或多个阴影效果,该属性几乎可以让你完成你想要的任何阴影效果。然而 box-shadow 属性语法和取值非常灵活,对于新手有点不容易理解。今天总结一下语法和 box-shadow 属性各种阴影效果。
语法
/* offset-x | offset-y | color */ box-shadow: 60px -16px teal; /* offset-x | offset-y | blur-radius | color */ box-shadow: 10px 5px 5px black; /* offset-x | offset-y | blur-radius | spread-radius | color */ box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.2); /* inset | offset-x | offset-y | color */ box-shadow: inset 5em 1em gold; /* Any number of shadows, separated by commas */ box-shadow: 3px 3px red, -1em 0 0.4em olive; /* Global keywords */ box-shadow: inherit; box-shadow: initial; box-shadow: unset;
取值说明:
inset: 默认阴影在边框外。使用 inset 后,阴影在边框内(即使是透明边框),背景之上内容之下。也有些人喜欢把这个值放在最后,浏览器也支持。
<offset-x> <offset-y>: 这是头两个 <length>值,用来设置阴影偏移量。<offset-x> 设置水平偏移量,如果是负值则阴影位于元素左边。 <offset-y> 设置垂直偏移量,如果是负值则阴影位于元素上面。可用单位请查看 <length>。如果两者都是0,那么阴影位于元素后面。这时如果设置了 <blur-radius> 或 <spread-radius> 则有模糊效果。
<blur-radius>: 这是第三个 <length> 值。值越大,模糊面积越大,阴影就越大越淡。 不能为负值。默认为0,此时阴影边缘锐利。
<spread-radius> : 这是第四个 <length> 值。取正值时,阴影扩大;取负值时,阴影收缩。默认为0,此时阴影与元素同样大。
<color> : 相关事项查看 <color> 。如果没有指定,则由浏览器决定——通常是color的值,不过目前Safari取透明。
网上找了几张图,大家可以对应的看一下,更加好理解。
再说的具体一点:
div { width: 150px; height: 150px; background-color: #fff; box-shadow: 120px 80px 40px 20px #0ff; /* 顺序为: offset-x, offset-y, blur-size, spread-size, color */ /* blur-size 和 spread-size 是可选的 (默认为 0) */ }
来个图解:
最简单的常规效果
下面是一些最简单的阴影效果,看代码也应该非常容易理解:
HTML
<div class="flex"> <div class="flex-item"> <h3>内阴影示例</h3> <div class="box boxshadow1"></div> </div> <div class="flex-item"> <h3>3边内影示例</h3> <div class="box boxshadow2"></div> </div> <div class="flex-item"> <h3>外阴影示例</h3> <div class="box boxshadow3"></div> </div> <div class="flex-item"> <h3>右下外阴影示例</h3> <div class="box boxshadow4"></div> </div> <div class="flex-item"> <h3>扩大阴影示例</h3> <div class="box boxshadow5"></div> </div> <div class="flex-item"> <h3>半透明阴影色示例</h3> <div class="box boxshadow6"></div> </div> </div>
CSS
.flex{display:flex;flex-wrap:wrap;} .flex-item{margin-right:30px;} .box { background-color: #CCCCCC; border-radius:10px; width: 200px; height: 200px; } .boxshadow1{ box-shadow:inset 0px 0px 5px 1px #000; } .boxshadow2{ box-shadow:inset 0 1px 2px 1px #000; } .boxshadow3{box-shadow:0 0 10px #000;} .boxshadow4{box-shadow:2px 2px 5px #000;} .boxshadow5{box-shadow:0 0 5px 15px #000;} .boxshadow6{box-shadow: 12px 12px 2px 1px rgba(0, 0, 255, .2);}
效果如下
单边阴影效果
单边阴影效果可以做一些效果,比如特殊场景下描边,小阴影,再比如一些过渡色。
HTML
<div class="flex"> <div class="flex-item"> <h3>上边内阴影示例</h3> <div class="box boxshadow1"></div> </div> <div class="flex-item"> <h3>右边内阴影示例</h3> <div class="box boxshadow2"></div> </div> <div class="flex-item"> <h3>下边外阴影示例</h3> <div class="box boxshadow3"></div> </div> <div class="flex-item"> <h3>右边外阴影示例</h3> <div class="box boxshadow4"></div> </div> <div class="flex-item"> <h3>下边细线示例</h3> <div class="box boxshadow5"></div> </div> </div>
CSS
.flex{display:flex;flex-wrap:wrap;} .flex-item{margin-right:30px;} .box { background-color: #CCCCCC; width: 200px; height: 200px; } .boxshadow1{ box-shadow:inset 0px 15px 10px -15px #000; } .boxshadow2{ box-shadow:inset -15px 0px 10px -15px #000;} .boxshadow3{box-shadow:0px 12px 8px -12px #000; border-radius:10px; } .boxshadow4{box-shadow:3px 0 8px -4px #000;} .boxshadow5{ box-shadow: inset 0px -1px 0px 0px rgb(0, 0, 0) ;}
效果如下
双边边阴影及多重阴影效果
HTML
<div class="flex"> <div class="flex-item"> <h3>上下边内阴影示例</h3> <div class="box boxshadow1"></div> </div> <div class="flex-item"> <h3>左右边外阴影示例</h3> <div class="box boxshadow2"></div> </div> <div class="flex-item"> <h3>多层阴影示例</h3> <div class="box boxshadow3"></div> </div> </div>
CSS
.flex{display:flex;flex-wrap:wrap;} .flex-item{margin-right:30px;} .box { background-color: #CCCCCC; width: 200px; height: 200px; } .boxshadow1{ box-shadow:inset 0px 15px 15px -15px #000, inset 0px -15px 15px -15px #000; } .boxshadow2{ box-shadow:15px 0 15px -15px #000, -15px 0 15px -15px #000; } .boxshadow3{ border-radius:10px; box-shadow:0px 0px 0px 3px #bb0a0a, 0px 0px 0px 6px #2e56bf, 0px 0px 0px 9px #ea982e; }
效果如下
其他一些有意思的阴影:
使用伪元素::before和::after,我们能创造出非常逼真的只有图片才能实现的阴影效果。让我来看一个例子:
HTML
<div class="box11 shadow"></div>
CSS
.box11 { width: 300px; height: 100px; background: #ccc; border-radius: 10px; margin: 10px; } .shadow { position: relative; max-width: 270px; box-shadow: 0px 1px 4px rgba(0,0,0,0.3), 0px 0px 20px rgba(0,0,0,0.1) inset; } .shadow::before, .shadow::after { content:""; position:absolute; z-index:-1; } .shadow::before, .shadow::after { content:""; position:absolute; z-index:-1; bottom:15px; left:10px; width:50%; height:20%; } .shadow::before, .shadow::after { content:""; position:absolute; z-index:-1; bottom:15px; left:10px; width:50%; height:20%; box-shadow:0 15px 10px rgba(0, 0, 0, 0.7); transform:rotate(-3deg); } .shadow::after{ right:10px; left:auto; transform:rotate(3deg); }
效果如下
再来一些效果:
HTML
<div class="wrap"> <div class="box box1 shadow1"> <h3>Shadow 1</h3> </div> <div class="box box2 shadow2"> <h3>Shadow 2</h3> </div> <div class="box box3 shadow3"> <h3>Shadow 3</h3> </div> <div class="box box4 shadow4"> <h3>Shadow 4</h3> </div> <div class="box box5 shadow5"> <h3>Shadow 5</h3> </div> <div class="box box6 shadow6"> <h3>Shadow 6</h3> </div> <div class="box box7 shadow7"> <h3>Shadow 7</h3> </div> <div class="box box8 shadow8"> <h3>Shadow 8</h3> </div> </div>
CSS
body{ background:#E6EEF6; } .wrap{ margin-left:20px; } .box{ width:40%; height:200px; float:left; background-color:white; margin:25px 15px; border-radius:5px; } .box h3{ font-family: 'Didact Gothic', sans-serif; font-weight:normal; text-align:center; padding-top:60px; color:#fff; } .box1{ background-color: #EBA39E; } .box2{ background-color: #EDE89A; } .box3{ background-color: #9EEBA1; } .box4{ background-color: #9EEBBF; } .box5{ background-color: #9ED9EB; } .box6{ background-color: #9EB3EB; } .box7{ background-color: #DB9EEB; } .box8{ background-color: #C49EEB; } .shadow1, .shadow2, .shadow3,.shadow4,.shadow5,.shadow6,.shadow7,.shadow8{ position:relative; } .shadow1,.shadow2,.shadow3,.shadow4,.shadow5,.shadow6,.shadow7,.shadow8{ box-shadow:0 1px 4px rgba(0, 0, 0, 0.3), 0 0 20px rgba(0, 0, 0, 0.1) inset; } /*****************************************************************dashed border ****************************************************************/ .shadow1 h3, .shadow2 h3, .shadow3 h3, .shadow4 h3, .shadow5 h3, .shadow6 h3, .shadow7 h3, .shadow8 h3{ width:87%; height:100px; margin-left:6%; border:2px dashed #F7EEEE; border-radius:5px; } /**************************************************************** *styling shadows ****************************************************************/ .shadow1:before, .shadow1:after{ position:absolute; content:""; bottom:12px;left:15px;top:80%; width:45%; background:#9B7468; z-index:-1; -webkit-box-shadow: 0 20px 15px #9B7468; -moz-box-shadow: 0 20px 15px #9B7468; box-shadow: 0 20px 15px #9B7468; -webkit-transform: rotate(-6deg); -moz-transform: rotate(-6deg); transform: rotate(-6deg); } .shadow1:after{ -webkit-transform: rotate(6deg); -moz-transform: rotate(6deg); transform: rotate(6deg); right: 15px;left: auto; } .shadow2:before{ position:absolute; content:""; width:80%; top:140px;bottom:15px;left:30px; background-color:#9F8641; z-index:-1; -webkit-box-shadow:0 23px 17px 0 #9F8641; -moz-box-shadow:0 23px 17px 0 #9F8641; box-shadow: 0 23px 17px 0 #9F8641; -webkit-transform:rotate(-4deg); -moz-transform:rotate(-4deg); transform:rotate(-4deg); } .shadow3:before, .shadow3:after{ content:""; position:absolute; bottom:0;top:2px;left:15px;right:15px; z-index:-1; border-radius:100px/30px; -webkit-box-shadow:0 0 30px 2px #479F41; -moz-box-shadow:0 0 30px 2px #479F41; box-shadow: 0 0 30px 2px #479F41; } .shadow4:before, .shadow4:after{ position:absolute; content:""; top:14px;bottom:14px;left:0;right:0; box-shadow:0 0 25px 3px #548E7F; border-radius:100px/10px; z-index:-1; } .shadow5:before, .shadow5:after{ position:absolute; content:""; box-shadow:0 10px 25px 20px #518C96; top:40px;left:10px;bottom:50px; width:15%; z-index:-1; -webkit-transform: rotate(-8deg); -moz-transform: rotate(-8deg); transform: rotate(-8deg); } .shadow5:after{ -webkit-transform: rotate(8deg); -moz-transform: rotate(8deg); transform: rotate(8deg); right: 10px;left: auto; } .shadow6:before, .shadow6:after{ position:absolute; content:""; top:100px;bottom:5px;left:30px;right:30px; z-index:-1; box-shadow:0 0 40px 13px #486685; border-radius:100px/20px; } .shadow7:before, .shadow7:after{ position:absolute; content:"1"; top:25px;left:20px;bottom:150px; width:80%; z-index:-1; -webkit-transform: rotate(-6deg); -moz-transform: rotate(-6deg); transform: rotate(-6deg); } .shadow7:before{ box-shadow:10px -10px 30px 15px #984D8E; } .shadow7:after{ -webkit-transform: rotate(7deg); -moz-transform: rotate(7deg); transform: rotate(7deg); bottom: 25px;top: auto; box-shadow:10px 10px 30px 15px #984D8E; } .shadow8{ box-shadow: -6px -6px 8px -4px rgba(250,254,118,0.75), 6px -6px 8px -4px rgba(254,159,50,0.75), 6px 6px 8px -4px rgba(255,255,0,0.75), 6px 6px 8px -4px rgba(0,0,255,2.75); }
效果如下