【CSS】CSS常用技巧

摘要：垂直对齐如果你用，则你会有困惑我该怎么垂直对齐容器中的元素现在，利用的，可以很优雅的解决这个困惑使用这个技巧，从单行文本段落到，都会垂直对齐。表格列宽自适用对于表格，当谈到调整列宽时，是比较痛苦的。

相信大家在写css属性的时候，会遇到一些问题，比如说：垂直对齐，垂直居中，背景渐变动画，表格宽度自适应，模糊文本，样式重置，清除浮动，通用媒体查询，自定义选择文本，强制出现滚动条，固定头部和页脚，自己在网上看到的一篇关于css的文章，感觉这里边一些常用的css代码片段对大家很有帮助，所以我就把这篇文章分享给大家，希望大家能够喜欢。

如果你用CSS，则你会有困惑：我该怎么垂直对齐容器中的元素？现在，利用CSS3的Transform，可以很优雅的解决这个困惑：

.verticalcenter{
    position: relative;
    top: 50%;
    -webkit-transform: translateY(-50%);
    -o-transform: translateY(-50%);
    transform: translateY(-50%);
}

使用这个技巧，从单行文本、段落到box，都会垂直对齐。目前浏览器对Transform的支持是需要关注的，

Chrome 4, Opera 10, Safari 3, Firefox 3, and Internet Explorer 9均支持该属性

在具体场景中，你可能想要将一个元素伸展到窗口高度，基本元素的调整只能调整容器的大小,因此要使一个元素伸展到窗口高度，
我们需要伸展顶层元素：html和body:

html, 
body {
    height: 100%;
}

然后将100%应用到任何元素的高

div {
    height: 100%;
}

为了更容易知道链接的目标，有时你想让一些链接看起来和其它的不同。下面的片段在文本链接前添加一个图标，对不同的资源使用不同的图标或图片：

a[href^="http://"]{
    padding-right: 20px;
    background: url(external.gif) no-repeat center right;
}
/* emails */
a[href^="mailto:"]{
    padding-right: 20px;
    background: url(email.png) no-repeat center right;
}

/* pdfs */
a[href$=".pdf"]{
    padding-right: 20px;
    background: url(pdf.png) no-repeat center right;
}

CSS中最具诱惑的一个功能是能添加动画效果，除了渐变，你可以给背景色、透明度、元素大小添加动画。目前，你不能为渐变添加动画，但下面的代码可能有帮助。它通过改变背景位置，让它看起来有动画效果。

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

对于表格，当谈到调整列宽时，是比较痛苦的。然后，这里有一个可以使用的技巧：给td元素添加white-space: nowrap;能让文本正确的换行

td {
    white-space: nowrap;
}

如果你要一个盒阴影，试试这个技巧，能为任一边添加阴影。为了实现这个，首先定义一个有具体宽高的盒子，然后正确定位:after伪类。实现底边阴影的代码如下

.box-shadow {
    background-color: #FF8020;
    width: 160px;
    height: 90px;
    margin-top: -45px;
    margin-left: -80px;
    position: absolute;
    top: 50%;
    left: 50%;
}
.box-shadow:after {
    content: "";
    width: 150px;
    height: 1px;
    margin-top: 88px;
    margin-left: -75px;
    display: block;
    position: absolute;
    left: 50%;
    z-index: -1;
    -webkit-box-shadow: 0px 0px 8px 2px #000000;
       -moz-box-shadow: 0px 0px 8px 2px #000000;
            box-shadow: 0px 0px 8px 2px #000000;
}

如果你碰到一个比自身容器长的文本，这个技巧对你很有用。在这个示例中，默认时，不管容器的宽度，文本都将水平填充。

简单的CSS代码就能在容器中调整文本：

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

效果看起来如下：

想要让文本模糊？可以使用color透明和text-shadow实现

.blurry-text {
   color: transparent;
   text-shadow: 0 0 5px rgba(0,0,0,0.5);
}

这个片段将帮助你制造一个ellipsis的动画，对于简单的加载状态是很有用的，而不用去使用gif图像。

.loading:after {
    overflow: hidden;
    display: inline-block;
    vertical-align: bottom;
    animation: ellipsis 2s infinite;
    content: "2026"; /* ascii code for the ellipsis character */
}
@keyframes ellipsis {
    from {
        width: 2px;
    }
    to {
        width: 15px;
    }
}

html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary, time, mark, audio, video {
  margin: 0;
  padding: 0;
  border: 0;
  font-size: 100%;
  font: inherit;
  vertical-align: baseline;
  outline: none;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
html { height: 101%; }
body { font-size: 62.5%; line-height: 1; font-family: Arial, Tahoma, sans-serif; }
article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section { display: block; }
ol, ul { list-style: none; }
blockquote, q { quotes: none; }
blockquote:before, blockquote:after, q:before, q:after { content: ""; content: none; }
strong { font-weight: bold; } 
table { border-collapse: collapse; border-spacing: 0; }
img { border: 0; max-width: 100%; }
p { font-size: 1.2em; line-height: 1.0em; color: #333; }

.clearfix:after {
 content: "."; 
 display: block;
 clear: both;
 visibility: hidden;
 line-height: 0;
 height: 0; 
}
.clearfix { display: inline-block; }
html[xmlns] .clearfix { display: block; }
* html .clearfix { height: 1%; }

.clearfix:before, .container:after { content: ""; display: table; }
.clearfix:after { clear: both; }
/* IE 6/7 */
.clearfix { zoom: 1; }

.transparent {
    filter: alpha(opacity=50); /* internet explorer */
    -khtml-opacity: 0.5;      /* khtml, old safari */
    -moz-opacity: 0.5;       /* mozilla, netscape */
    opacity: 0.5;           /* fx, safari, opera */
}

/* Smartphones (portrait and landscape) ----------- */
@media only screen 
and (min-device-width : 320px) and (max-device-width : 480px) {
  /* Styles */
}
/* Smartphones (landscape) ----------- */
@media only screen and (min-width : 321px) {
  /* Styles */
}
/* Smartphones (portrait) ----------- */
@media only screen and (max-width : 320px) {
  /* Styles */
}
/* iPads (portrait and landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) {
  /* Styles */
}
/* iPads (landscape) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) {
  /* Styles */
}
/* iPads (portrait) ----------- */
@media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) {
  /* Styles */
}
/* Desktops and laptops ----------- */
@media only screen and (min-width : 1224px) {
  /* Styles */
}
/* Large screens ----------- */
@media only screen and (min-width : 1824px) {
  /* Styles */
}
/* iPhone 4 ----------- */
@media only screen and (-webkit-min-device-pixel-ratio:1.5), only screen and (min-device-pixel-ratio:1.5) {
  /* Styles */
}

::selection { background: #e2eae2; }
::-moz-selection { background: #e2eae2; }
::-webkit-selection { background: #e2eae2; }

h1 {
    text-indent: -9999px;
    margin: 0 auto;
    width: 320px;
    height: 85px;
    background: transparent url("images/logo.png") no-repeat scroll;
}

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

html { 
    background: url("images/bg.jpg") no-repeat center center fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

.container {
    min-height: 6.5em;
    display: table-cell;
    vertical-align: middle;
} 

html { height: 101% }

#colorbox {
    background: #629721;
    background-image: -webkit-gradient(linear, left top, left bottom, from(#83b842), to(#629721));
    background-image: -webkit-linear-gradient(top, #83b842, #629721);
    background-image: -moz-linear-gradient(top, #83b842, #629721);
    background-image: -ms-linear-gradient(top, #83b842, #629721);
    background-image: -o-linear-gradient(top, #83b842, #629721);
    background-image: linear-gradient(top, #83b842, #629721);
}

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

#mydiv { 
    -moz-box-shadow: inset 2px 0 4px #000;
    -webkit-box-shadow: inset 2px 0 4px #000;
    box-shadow: inset 2px 0 4px #000;
}

#mydiv { 
    -webkit-box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.52);
    -moz-box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.52);
    box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.52);
}

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;
}

#page-wrap {
    width: 800px;
    margin: 0 auto;
}

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

#footer {
    position: fixed;
    left: 0px;
    bottom: 0px;
    height: 30px;
    width: 100%;
    background: #444;
}
/* IE 6 */
* html #footer {
    position: absolute;
    top: expression((0-(footer.offsetHeight)+(document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.clientHeight)+(ignoreMe = document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop))+"px");
}

#container {
    min-height: 550px;
    height: auto !important;
    height: 550px;
}

input[type=text], textarea {
    -webkit-transition: all 0.30s ease-in-out;
    -moz-transition: all 0.30s ease-in-out;
    -ms-transition: all 0.30s ease-in-out;
    -o-transition: all 0.30s ease-in-out;
    outline: none;
    padding: 3px 0px 3px 3px;
    margin: 5px 1px 3px 0px;
    border: 1px solid #ffffd;
}
input[type=text]:focus, textarea: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);
}

/* external links */
a[href^="http://"] {
    padding-right: 13px;
    background: url("external.gif") no-repeat center right;
}
/* emails */
a[href^="mailto:"] {
    padding-right: 20px;
    background: url("email.png") no-repeat center right;
}
/* pdfs */
a[href$=".pdf"] {
    padding-right: 18px;
    background: url("acrobat.png") no-repeat center right;
}

pre {
    white-space: pre-wrap;       /* css-3 */
    white-space: -moz-pre-wrap;  /* Mozilla, since 1999 */
    white-space: -pre-wrap;      /* Opera 4-6 */
    white-space: -o-pre-wrap;    /* Opera 7 */
    word-wrap: break-word;       /* Internet Explorer 5.5+ */
}

a[href], input[type="submit"], input[type="image"], label[for], select, button, .pointer {
    cursor: pointer;
}

.chat-bubble {
    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;
    -moz-border-radius: 20px;
    -webkit-border-radius: 20px;
    -moz-box-shadow: 0 0 5px #888;
    -webkit-box-shadow: 0 0 5px #888;
    font-family: "Bangers", arial, serif; 
}
.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;
}

h1,h2,h3,h4,h5{
    color: #005a9c;
}
h1{
    font-size: 2.6em;
    line-height: 2.45em;
}
h2{
    font-size: 2.1em;
    line-height: 1.9em;
}
h3{
    font-size: 1.8em;
    line-height: 1.65em;
}
h4{
    font-size: 1.65em;
    line-height: 1.4em;
}
h5{
    font-size: 1.4em;
    line-height: 1.25em;
}

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; 
}
/* Tooltip styling */
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;
}

.graybtn {
    -moz-box-shadow:inset 0px 1px 0px 0px #ffffff;
    -webkit-box-shadow:inset 0px 1px 0px 0px #ffffff;
    box-shadow:inset 0px 1px 0px 0px #ffffff;
    background:-webkit-gradient( linear, left top, left bottom, color-stop(0.05, #ffffff), color-stop(1, #d1d1d1) );
    background:-moz-linear-gradient( center top, #ffffff 5%, #d1d1d1 100% );
    filter:progid:DXImageTransform.Microsoft.gradient(startColorstr="#ffffff", endColorstr="#d1d1d1");
    background-color:#ffffff;
    -moz-border-radius:6px;
    -webkit-border-radius:6px;
    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:-webkit-gradient( linear, left top, left bottom, color-stop(0.05, #d1d1d1), color-stop(1, #ffffff) );
    background:-moz-linear-gradient( center top, #d1d1d1 5%, #ffffff 100% );
    filter:progid:DXImageTransform.Microsoft.gradient(startColorstr="#d1d1d1", endColorstr="#ffffff");
    background-color:#d1d1d1;
}
.graybtn:active {
    position:relative;
    top:1px;
}

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

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

p {
  font: italic small-caps bold 1.2em/1.0em Arial, Tahoma, Helvetica;
}

ul.box {
    position: relative;
    z-index: 1; /* prevent shadows falling behind containers with backgrounds */
    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); 
}

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;
    -webkit-transition: all .3s ease-in-out;
}
a:hover, .glow {
    color: #ff0;
    text-shadow: 0 0 10px #ff0;
}

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

CSS过滤器属性能够实现将图片变为灰色
（支持Firefox 3.5+, Opera 15+, Safari, Chrome, and IE）

-webkit-filter: grayscale(100%);  
-webkit-filter: grayscale(1);  
filter: grayscale(100%);  
filter: gray;

    
    
文字


.image-text {
    display:inline-block;
    vertical-align:middle;
}

transform: scale(-1, 1);//水平翻转
transform: scale(1, -1);//垂直翻转