CSS的一些小技巧

1.黑白图像
img.desaturate {
filter: grayscale(100%);
-webkit-filter: grayscale(100%);
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale(100%);
}
2. 使用 :not() 在菜单上应用/取消应用边框
/* add border */
.nav li {
border-right: 1px solid #666;
}
.nav li:not(:last-child) {
border-right: 1px solid #666;
}
3. 页面顶部阴影
body:before {
content: "";
position: fixed;
top: -10px;
left: 0;
width: 100%;
height: 10px;

-webkit-box-shadow: 0px 0px 10px rgba(0,0,0,.8);
-moz-box-shadow: 0px 0px 10px rgba(0,0,0,.8);
box-shadow: 0px 0px 10px rgba(0,0,0,.8);

z-index: 100;
}
4.给 body 添加行高
body {
line-height: 1;
}
5.所有一切都垂直居中
html, body {
height: 100%;
margin: 0;
}

body {
-webkit-align-items: center;
-ms-flex-align: center;
align-items: center;
display: -webkit-flex;
display: flex;
}
6.逗号分隔的列表
ul > li:not(:last-child)::after {
content: ",";
}
7.使用负的 nth-child 选择项目
li {
display: none;
}

/* select items 1 through 3 and display them */
li:nth-child(-n+3) {
display: block;
}
8.对图标使用 SVG
.logo {
background: url("logo.svg");
}
9.优化显示文本
html {
-moz-osx-font-smoothing: grayscale;
-webkit-font-smoothing: antialiased;
text-rendering: optimizeLegibility;
}
10.对纯 CSS 滑块使用 max-height
.slider ul {
max-height: 0;
overlow: hidden;
}

.slider:hover ul {
max-height: 1000px;
transition: .3s ease;
}
11.继承 box-sizing
html {
box-sizing: border-box;
}

*, *:before, *:after {
box-sizing: inherit;
}
12.表格单元格等宽
.calendar {
table-layout: fixed;
}
13.用 Flexbox 摆脱外边距的各种 hack
.list {
display: flex;
justify-content: space-between;
}

.list .person {
flex-basis: 23%;
}
14.使用属性选择器用于空链接
a[href^="http"]:empty::before {
content: attr(href);
}
15.检测鼠标双击
HTML
<div class="test3">
<span><input type="text" value=" " readonly="true" />
<a href="http://renpingjun.com">Double click me</a></span>
</div>
CSS
.test3 span {
position: relative;
}
.test3 span a {
position: relative;
z-index: 2;
}
.test3 span a:hover, .test3 span a:active {
z-index: 4;
}
.test3 span input {
background: transparent;
border: 0;
cursor: pointer;
position: absolute;
top: -1px;
left: 0;
width: 101%; /* Hacky */
height: 301%; /* Hacky */
z-index: 3;
}
.test3 span input:focus {
background: transparent;
border: 0;
z-index: 1;
}
16.CSS 写出三角形
/* create an arrow that points up */
div.arrow-up {
width:0px;
height:0px;
border-left:5px solid transparent; /* left arrow slant */
border-right:5px solid transparent; /* right arrow slant */
border-bottom:5px solid #2f2f2f; /* bottom, add background color here */
font-size:0px;
line-height:0px;
}

/* create an arrow that points down */
div.arrow-down {
width:0px;
height:0px;
border-left:5px solid transparent;
border-right:5px solid transparent;
border-top:5px solid #2f2f2f;
font-size:0px;
line-height:0px;
}

/* create an arrow that points left */
div.arrow-left {
width:0px;
height:0px;
border-bottom:5px solid transparent; /* left arrow slant */
border-top:5px solid transparent; /* right arrow slant */
border-right:5px solid #2f2f2f; /* bottom, add background color here */
font-size:0px;
line-height:0px;
}

/* create an arrow that points right */
div.arrow-right {
width:0px;
height:0px;
border-bottom:5px solid transparent; /* left arrow slant */
border-top:5px solid transparent; /* right arrow slant */
border-left:5px solid #2f2f2f; /* bottom, add background color here */
font-size:0px;
line-height:0px;
}
17.CSS3 calc() 的使用
/* basic calc */
.simpleBlock {
width: calc(100% - 100px);
}

/* calc in calc */
.complexBlock {
width: calc(100% - 50% / 3);
padding: 5px calc(3% - 2px);
margin-left: calc(10% + 10px);
}
18.文本渐变
h2[data-text] {
position: relative;
}
h2[data-text]::after {
content: attr(data-text);
z-index: 10;
color: #e3e3e3;
position: absolute;
top: 0;
left: 0;
-webkit-mask-image: -webkit-gradient(linear, left top, left bottom, from(rgba(0,0,0,0)), color-stop(50%, rgba(0,0,0,1)), to(rgba(0,0,0,0)));}
19.禁用鼠标事件
.disabled { pointer-events: none; }
20.模糊文本
.blur {
color: transparent;
text-shadow: 0 0 5px rgba(0,0,0,0.5);
}