垂直居中

.vc {
   position: absolute;
   top: 50%;
   left: 50%;
   transform: translate(-50%, -50%);
}
.vc {
   position:absolute;
   top: 50%;
   left: 50%;
   width: 100px;
   height: 100px;
   margin:-50px 0 -50px;
}
.vc {
   display: flex;
   justify-content: center; /* 水平居中 */
   align-items: center;     /* 垂直居中 */
   width: 1000px;
   height: 600px;
}
.vc {
    min-height: 6.5em;
    display: table-cell;
    vertical-align: middle;
}

伪类 + transform 实现移动端 Retina 屏幕 1px 边框

//单条边框
.scale-1px {
  position: relative;
  border: none;
}
.scale-1px:after {
  content: '';
  position: absolute;
  bottom: 0;
  background: #000;
  width: 100%;
  height: 1px;
  -webkit-transform: scaleY(0.5);
  transform: scaleY(0.5);
  -webkit-transform-origin: 0 0;
  transform-origin: 0 0;
}
//四条boder样式设置:
.scale-1px {
  position: relative;
  margin-bottom: 20px;
  border: none;
}
.scale-1px:after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  border: 1px solid #000;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
  width: 200%;
  height: 200%;
  -webkit-transform: scale(0.5);
  transform: scale(0.5);
  -webkit-transform-origin: left top;
  transform-origin: left top;
}

flex常用布局盒结构

//两端对齐 垂直居中盒
.justify-box{
    display: flex;
    justify-content: space-between; //两端对齐
    //space-around等距分布 flex-start起始位置对齐center居中flex-start末尾位置对齐
    align-items: center;
   //flex-start：交叉轴的起点对齐。flex-end：交叉轴的终点对齐。
}

关于flex布局后期需另外写一篇文章总结

未知图片宽高实现图片等比例缩放裁切适应不同比例容器

//方法一运用背景有宽高方法图办法
.div {
  width: 80px;  //宽高一定要有
  height: 80px;
  background: url("../img/test.jpg");
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center center;
}
//方法二利用padding-bottom确定比例继承父容器宽加背景图方式
.zoomImage{
    width:100%;
    height:0;
    padding-bottom: 100%;  //div以1：1的大小呈现 
    // 75%时宽高比例4：3，133.33时宽高比例3：4，
    overflow:hidden;
    background: url("../img/test.jpg");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center center;
}
//方法三 position定位方法实现
.works-item-t {
    padding-bottom: 133%;
    position: relative;
}
.works-item-t > img {
    position: absolute;
    width: 100%; height: 100%;
}

强制文本两端对齐，防止两边距离不等

.text-info{
  max-width: 100% !important;
  box-sizing: border-box !important;
  -webkit-box-sizing: border-box !important;
  word-wrap: break-word !important;
  text-align: justify !important;
  text-justify: inter-ideograph;
}

多行文字弹性带渐隐效果截断加省略号

.wrap {
  height: 40px;
  line-height: 20px;
  overflow: hidden;
}
.wrap .text {
  float: right;
  margin-left: -5px;
  width: 100%;
  word-break: break-all;
}
.wrap::before {
  float: left;
  width: 5px;
  content: '';
  height: 40px;
}
.wrap::after {
  float: right;
  content: "...";
  height: 20px;
  line-height: 20px;
  /* 为三个省略号的宽度 */
  width: 3em;
  /* 使盒子不占位置 */
  margin-left: -3em;
  /* 移动省略号位置 */
  position: relative;
  left: 100%;
  top: -20px;
  padding-right: 5px;
}

图像灰度

img {
    filter: gray; 
    -webkit-filter: grayscale(1);
}

至少一屏高

div {
    min-height: 100vh;
}

不同a标签链接使用不同样式

// link

a[href^="http://"]{
    background: url(link.gif) no-repeat center right;
}
// emails
a[href^="mailto:"]{
    background: url(email.png) no-repeat center right;
}

// pdfs

a[href$=".pdf"]{
    background: url(pdf.png) no-repeat center right;
}

背景渐变动画

bg {
    background-image: linear-gradient(#5187c4, #1c2f45);
    background-size: auto 200%;
    background-position: 0 100%;
    transition: background-position 0.5s;
}    
bg:hover {
    background-position: 0 0;
}

长文本自动换行

pre {
    white-space: pre-line;
    word-wrap: break-word;
}

模糊文本

.text {
   filter: blur(1px);
}

用CSS动画实现省略号动画

.point:after {
    overflow: hidden;
    display: inline-block;
    vertical-align: bottom;
    animation: ellipsis 2s infinite;
    content: "\2026";
}
@keyframes ellipsis {
    from {
        width: 2px;
    }
    to {
        width: 15px;
    }
}

css元素透明

.transparent {
    filter: alpha(opacity=50); 
    -khtml-opacity: 0.5; 
    -moz-opacity: 0.5;   
    opacity: 0.5;     
}

个性圆角

.borderRadius {
    border-radius: 4px 3px 6px 10px;
}
.borderRadius {
    border-top-left-radius: 4px;
    border-top-right-radius: 3px;
    border-bottom-right-radius: 6px;
    border-bottom-left-radius: 10px;
}

通用媒体查询

@media only screen and (min-device-width : 320px) and (max-device-width : 480px) {
  /* Styles */
}
@media only screen and (min-width : 321px) {
  /* Styles */
}
@media only screen and (max-width : 320px) {
  /* Styles */
}
/* iPad */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) {
  /* Styles */
}
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) {
  /* Styles */
}

@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) {
  /* Styles */
}
/* 桌面 */
@media only screen and (min-width : 1224px) {
  /* Styles */
}

@media only screen and (min-width : 1824px) {
  /* Styles */
}

@media only screen and (-webkit-min-device-pixel-ratio:1.5), only screen and (min-device-pixel-ratio:1.5) {
  /* Styles */
}

图片边框偏光

img.polaroid {
    background:#000; 
    border:solid #fff;
    border-width:6px 6px 20px 6px;
    box-shadow:1px 1px 5px #333; 
    -webkit-box-shadow:1px 1px 5px #333;
    -moz-box-shadow:1px 1px 5px #333;
    height:200px; 
    width:200px;  
}

锚链接伪类

a:link { color: blue; }
a:visited { color: purple; }
a:hover { color: red; }
a:active { color: yellow; }

全屏背景图

html { 
    background: url('bg.jpg') no-repeat center center fixed; 
    background-size: cover;
}

强制出现垂直滚动条

html { height: 101% }

CSS3渐变模板

.bg {
    background: #629721;
    background-image: -webkit-gradient(linear, left top, left bottom, from(#83b842), to(#629721));
    background-image: linear-gradient(top, #83b842, #629721);
}
[特殊的渐变推荐一个 CSS 渐变代码自动生成工具，可以自动生成线性渐变代码](https://www.bestvist.com/css-gradient)

@font-face引用

@font-face {
    font-family: 'MyWebFont';
    src: url('webfont.eot'); 
    src: url('webfont.eot?#iefix') 
    url('webfont.woff') format('woff'), 
    url('webfont.ttf')  format('truetype'),
    url('webfont.svg#svgFontName') format('svg');
}
body {
    font-family: 'MyWebFont', Arial, sans-serif;
}

CSS斑马线

tbody tr:nth-child(odd) {
    background-color: #ccc;
}

内盒阴影

.div { 
    box-shadow: inset 2px 0 4px rgba(0, 0, 0, 0.3);
}

外盒阴影

.div { 
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.3);
}

三角形列表项目符号

ul {
    margin: 0.75em 0;
    padding: 0 1em;
    list-style: none;
}
li:before { 
    content: "";
    border-color: transparent #111;
    border-style: solid;
    border-width: 0.35em 0 0.35em 0.45em;
    display: block;
    height: 0;
    width: 0;
    left: -1em;
    top: 0.9em;
    position: relative;
}

CSS3列文本

.columnsText {
    text-align: justify;
    -webkit-column-count: 3;
    -webkit-column-gap: 12px;
    -webkit-column-rule: 1px solid #c4c8cc;
}

CSS3输入效果

input[type=text] {
    transition: all 0.30s ease-in-out;
    outline: none;
    padding: 3px 0px 3px 3px;
    margin: 5px 1px 3px 0px;
    border: 1px solid #ddd;
}
input[type=text]:focus {
    box-shadow: 0 0 5px rgba(81, 203, 238, 1);
    padding: 3px 0px 3px 3px;
    margin: 5px 1px 3px 0px;
    border: 1px solid rgba(81, 203, 238, 1);
}

强制换行

pre {
    white-space: pre-wrap;        
    word-wrap: break-word;  
}

在可点击的项目上强制手型

.pointer {
    cursor: pointer;
}

网页顶部盒阴影

body:before {
    content: "";
    position: fixed;
    top: -10px;
    left: 0;
    width: 100%;
    height: 10px;
    box-shadow: 0px 0px 10px rgba(0,0,0,.8);
    z-index: 100;
}

CSS3对话气泡

.line {
    background-color: #ededed;
    border: 2px solid #666;
    font-size: 35px;
    line-height: 1.3em;
    margin: 10px auto;
    padding: 10px;
    position: relative;
    text-align: center;
    width: 300px;
    border-radius: 20px;
    box-shadow: 0 0 5px #888;
}
.chat-bubble-arrow-border {
    border-color: #666 transparent transparent transparent;
    border-style: solid;
    border-width: 20px;
    height: 0;
    width: 0;
    position: absolute;
    bottom: -42px;
    left: 30px;
}
.chat-bubble-arrow {
    border-color: #ededed transparent transparent transparent;
    border-style: solid;
    border-width: 20px;
    height: 0;
    width: 0;
    position: absolute;
    bottom: -39px;
    left: 30px;
}

CSS悬浮提示文本

a { 
    border-bottom:1px solid #bbb;
    color:#666;
    display:inline-block;
    position:relative;
    text-decoration:none;
}
a:hover,
a:focus {
    color:#36c;
}
a:active {
    top:1px; 
}

a[data-tooltip]:after {
    border-top: 8px solid #222;
    border-top: 8px solid hsla(0,0%,0%,.85);
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    content: "";
    display: none;
    height: 0;
    width: 0;
    left: 25%;
    position: absolute;
}
a[data-tooltip]:before {
    background: #222;
    background: hsla(0,0%,0%,.85);
    color: #f6f6f6;
    content: attr(data-tooltip);
    display: none;
    font-family: sans-serif;
    font-size: 14px;
    height: 32px;
    left: 0;
    line-height: 32px;
    padding: 0 15px;
    position: absolute;
    text-shadow: 0 1px 1px hsla(0,0%,0%,1);
    white-space: nowrap;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
}
a[data-tooltip]:hover:after {
    display: block;
    top: -9px;
}
a[data-tooltip]:hover:before {
    display: block;
    top: -41px;
}
a[data-tooltip]:active:after {
    top: -10px;
}
a[data-tooltip]:active:before {
    top: -42px;
}

深灰色的圆形按钮

.graybtn {
    box-shadow:inset 0px 1px 0px 0px #ffffff;
    background:gradient( linear, left top, left bottom, color-stop(0.05, #ffffff), color-stop(1, #d1d1d1) );
    filter:progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#d1d1d1');
    background-color:#ffffff;
    border-radius:6px;
    border:1px solid #dcdcdc;
    display:inline-block;
    color:#777777;
    font-family:arial;
    font-size:15px;
    font-weight:bold;
    padding:6px 24px;
    text-decoration:none;
    text-shadow:1px 1px 0px #ffffff;
}
.graybtn:hover {
    background:gradient( linear, left top, left bottom, color-stop(0.05, #d1d1d1), color-stop(1, #ffffff) );
    filter:progid:DXImageTransform.Microsoft.gradient(startColorstr='#d1d1d1', endColorstr='#ffffff');
    background-color:#d1d1d1;
}
.graybtn:active {
    position:relative;
    top:1px;
}

显示a链接的URLs

@media print   {  
  a:after {  
    content: " [" attr(href) "] ";  
  }  
}

禁用移动Webkit的选择高亮

body {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

CSS3 圆点图案

body {
    background: radial-gradient(circle, white 10%, transparent 10%),
    radial-gradient(circle, white 10%, black 10%) 50px 50px;
    background-size: 100px 100px;
}

CSS3 方格图案

body {
    background-color: white;
    background-image: linear-gradient(45deg, black 25%, transparent 25%, transparent 75%, black 75%, black), 
    linear-gradient(45deg, black 25%, transparent 25%, transparent 75%, black 75%, black);
    background-size: 100px 100px;
    background-position: 0 0, 50px 50px;
}

论文页面的卷曲效果

ul.box {
    position: relative;
    z-index: 1;
    overflow: hidden;
    list-style: none;
    margin: 0;
    padding: 0; 
}
ul.box li {
    position: relative;
    float: left;
    width: 250px;
    height: 150px;
    padding: 0;
    border: 1px solid #efefef;
    margin: 0 30px 30px 0;
    background: #fff;
    -webkit-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset;
    -moz-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset; 
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset; 
}
ul.box li:before,
ul.box li:after {
    content: '';
    z-index: -1;
    position: absolute;
    left: 10px;
    bottom: 10px;
    width: 70%;
    max-width: 300px; /* avoid rotation causing ugly appearance at large container widths */
    max-height: 100px;
    height: 55%;
    -webkit-box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    -webkit-transform: skew(-15deg) rotate(-6deg);
    -moz-transform: skew(-15deg) rotate(-6deg);
    -ms-transform: skew(-15deg) rotate(-6deg);
    -o-transform: skew(-15deg) rotate(-6deg);
    transform: skew(-15deg) rotate(-6deg); 
}
ul.box li:after {
    left: auto;
    right: 10px;
    -webkit-transform: skew(15deg) rotate(6deg);
    -moz-transform: skew(15deg) rotate(6deg);
    -ms-transform: skew(15deg) rotate(6deg);
    -o-transform: skew(15deg) rotate(6deg);
    transform: skew(15deg) rotate(6deg); 
}

鲜艳的锚链接

a {
    color: #00e;
}
a:visited {
    color: #551a8b;
}
a:hover {
    color: #06e;
}
a:focus {
    outline: thin dotted;
}
a:hover, a:active {
    outline: 0;
}
a, a:visited, a:active {
    text-decoration: none;
    color: #fff;
    transition: all .3s ease-in-out;
}
a:hover, .glow {
    color: #ff0;
    text-shadow: 0 0 10px #ff0;
}

带CSS3特色的横幅显示

.featureBanner {
    position: relative;
    margin: 20px
}
.featureBanner:before {
    content: "Featured";
    position: absolute;
    top: 5px;
    left: -8px;
    padding-right: 10px;
    color: #232323;
    font-weight: bold;
    height: 0px;
    border: 15px solid #ffa200;
    border-right-color: transparent;
    line-height: 0px;
    box-shadow: -0px 5px 5px -5px #000;
    z-index: 1;
}
.featureBanner:after {
    content: "";
    position: absolute;
    top: 35px;
    left: -8px;
    border: 4px solid #89540c;
    border-left-color: transparent;
    border-bottom-color: transparent;
}

限制单行文本超出显示省略号

div{
    width: 65px;
    height: 30px;
    line-height: 30px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 14px;
}

限制多行文本超出省略号

div{
    overflow : hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

css三角形绘制

.sj {
    width: 0; 
    height: 0;
    border-width: 100px;
    border-style: solid;
}

.sj-left {
    border-color: transparent pink transparent transparent;
}

.sj-right {
    border-color: transparent transparent transparent pink;
}

.sj-top {
    border-color: transparent transparent pink transparent;
}

.sj-bottom {
    border-color: pink transparent transparent transparent;
}

自适应文本框自动换行，限宽不限高

div{
    display: inline-block;
    min-height: 15px;
    max-width: 78%;
    padding: 12px 10px;
    text-align: left;
    font-family: Microsoft YaHei;
    word-wrap: break-word;
}

~选择器：查找某一个元素后面的所有兄弟元素

例如     .test~.name{background:red}

+选择器：查找某一个元素后面紧邻的兄弟元素

例如     .test+.name{background:red}

用 font-size ：0 来清除边距

利用padding实现等比例缩放的盒子

最外层容器{
    display:flex;
    display:flex-box;
    flex-wrap:warp;
}
最外层容器 > 子元素{
    flex-basis:25%;
}
最外层容器 > 子元素 > 父元素{
    width:100%;
    padding-top:75%;
    position:relative;
}
最外层容器 > 子元素 > 父元素 > 子元素{
    width:100%;
    height:100%;
    position:absolute;
    top:0;
    left:0;
}

利用pointer-events禁用事件光标变成default阻止hover和hover以及JavaScript 点击事件的触发

pointer-events:none;

利用 max-width 防止图片撑破容器

img{
    max-width：100%；
    display：inline-block;
}

伪类和伪元素的用法

 // 伪类是用 : 来表示，伪元素是用 :: 来表示
  //常见的伪类有：
    :hover
    :active
    :focus
    :visited
    :link
    :lang
    :first-child
    :last-child
    :not
    :nth-child
           
// 伪元素就是不存在DOM文档树中的虚拟元素，它们和HTML元素一样，但是你又无法使用javascript去获取

//常见伪元素
    ::before
    ::after
    ::first-letter
    ::first-line 
           
           
//用 :valid  和 :invalid 来做表单验证

    //html5 提供了类似required Email tel 等表单属性
    :required // 指定具有required属性的表单元素
    :valid // 指定一个通过匹配正确的所要求的表单元素
    :invalid // 指定一个不匹配指定要求的表单元素

<input type="text" required />   
    input:vaild{    //如果输入文字则变成绿色
        border:1px solid green;
        box-shadow:inset 10px 0 0 green;
    }
    input:invaild{   //如果没有输入则是红色
        border:1px solid red;
        box-shadow:inset 10px 0 0 red;
    }
                        
//用:target来实现折叠面板

//用:not来排除其他选择器
  :not([readonly]):not([.disabled]):not([text])  
  
//用:nth-child 来实现各行变色
  :nth-child(2n+1){background:red;}
  :nth-child(2n){backgorund:blue;}
  

//用::selection 来美化选中文本
    p::selection{
        background:red;
        color:green;
    }

//用::placeholder 美化输入框占位符样式
    ::placeholder{
        color:Red;
    }
   
//用::first-letter 来实现段落首字下沉
    p::first-letter{
        font-size:30px;
        color:Red;
        padding:20px;
    }

//用::first-line 来标记段落的第一行
    p::first-line{
        color:red;
    }

消除transition闪屏

.css {
    transform: translate3d(0,0,0);
}