CSS--使用伪选择器制作箭头图标

// 使用Transform的属性，组合translate（位移）和rotate（旋转），将生成的小矩形组合成各种箭头样式；

HTML

 <section class="main">
     <header class="title">图标变形过渡效果缩放式菜单</header>
     <section>
         <button>图标</button>
         <header>
             #300x100 淡色系
         </header>
         <div>
             <article>
                 <img src="http://www.gbtags.com/gb/laitu/300x100" alt="" />
             </article>
         </div>
     </section>
     <section>
         <button>图标</button>
         <header>
             #300x100 暗色系
         </header>
         <div>
             <article>
                 <img src="http://www.gbtags.com/gb/laitu/300x100/666666/ffffff" alt="" />
             </article>
         </div>
     </section>
 </section>

CSS

 * { box-sizing:border-box;}
 body { font-family: 'microsoft yahei',Arial,sans-serif; background: #aaa;}
 section { position: relative; width:100%;}
 section.main { position: absolute; top:10%; left:25%;  width:50%; max-width:30em; min-width:15em; border-radius:5px; overflow: hidden;}
 section.main > header { background: orange; color:#fff; line-height: 1.2em; text-align: center;}
 section section:last-child { border:none;}
 section > div { height:; overflow: hidden; transition:all .4s ease-in-out;}
 article,header { padding:1em; line-height: 1em;}
 header:not(.title) { width:100%; overflow: hidden; height:3em; background: #efefef; cursor:pointer; color:#888; white-space:nowrap; text-overflow: ellipsis; padding-right: 2.1em;}
 header:not(.title):hover { background: #e8e8e8;}
 article { line-height: 1.4em; background: rgba(255, 255, 255, .7);}
 article img { width:100%; height:auto; border:2px solid white; border-radius: 3px;}

 /* 使用CSS3的伪选择器,生成关闭和向下两个图标按钮; */
 /* 使用变形属性,组合位移和旋转,可将生成的小矩形组合成向下按钮,同样也可以组装成关闭按钮; */
 section button { position: absolute; right:; margin:; padding:; height:3em; width:3em; outline:none; border:; background: none; text-indent: -9999px; pointer-events:none; cursor:pointer;}
 section button:before,
 section button:after { content:''; display: block; position: absolute; width:4px; height:12px; background: orange; border-radius: .3em; top:50%; left:50%; transition:all .3s ease-in-out;}

 /*向左箭头*/
 /*section button:before { transform:translate(0%, -50%) rotate(45deg);}
 section button:after { transform:translate(0%, 0%) rotate(-45deg);}*/

 /*向右箭头*/
 /*section button:before { transform:translate(0%, -50%) rotate(-45deg);}
 section button:after { transform:translate(0%, 0%) rotate(45deg);}*/

 /*向上箭头*/
 /*section button:before { transform:translate(75%, -20%) rotate(-45deg);}
 section button:after { transform:translate(-75%, -20%) rotate(45deg);}*/

 /*向下箭头*/
 section button:before { transform:translate(75%, 0%) rotate(45deg);}
 section button:after { transform:translate(-75%, 0%) rotate(-45deg);}

 /* 点击之后需要变成"X"; */
 section.open button:after,section.open button:before { background: red; height:14px; }
 section.open button:before { transform:translate(-75%, -20%) rotate(45deg);}
 section.open button:after { transform:translate(-75%, -20%) rotate(-45deg);}

JavaScript

 $(function(){
     $('section section header').on('click', function () {
         var $this = $(this),
             parent_section = $this.parent(),
             closeDiv = $this.siblings('div'),
             contentheight = closeDiv.children('article').outerHeight();
         (closeDiv.height() === 0 ) ? closeDiv.height(contentheight) : closeDiv.height(0);
         // 更改容器高度;
         $this.parents('section').first().toggleClass('open');
         // 更改箭头样式;
     });
 });