[css3]搜索框focus时变长

结构：

<form class="demo-a">
    <input placeholder="Search" type="search">
</form>

关键样式：

.demo-a input{width: 15px; border-radius: 10em; transition: all 0.5s ease 0s;}

.demo-a input:focus{width: 130px; box-shadow: 0 0 5px rgba(109,207,246,.5);}