HTML+CSS实现动态背景登录页面

.form_login input[type="text"]:focus,input[type="password"]:focus{
    -webkit-transition:border linear .2s,-webkit-box-shadow linear .5s;     /*对边框颜色的逐步过渡高亮显示，后面是对阴影的逐步过渡*/
    border-color:rgba(255,128,0,.75);
}

text-shadow:0px -1px 0px #5b6ddc;       /*文字阴影设置*/
outline:none;
border:1px solid rgba(0,0,0,0.49);       /*按钮边框颜色与透明度设置*/
-webkit-background-clip: padding-box;   /*规定内容的绘制区域，padding-box为内边框距*/
background-clip: padding-box;
border-radius:6px;
cursor:pointer;     /*光标形状，pointer为一只手的形状*/
background-color:#768ee4;       /*按钮背景颜色*/

.form_login input[type="submit"]:hover{
    background-color:#5f73e9;
    background-image:-webkit-linear-gradient(bottom,#5f73e9 0%,#859bef 100%);
    background-image:-moz-linear-gradient(bottom,#5f73e9 0%,#859bef 100%);
    background-image:-ms-linear-gradient(bottom,#5f73e9 0%,#859bef 100%);
    background-image:-o-linear-gradient(bottom,#5f73e9 0%,#859bef 100%);
    -webkit-box-shadow: inset 0px 1px 0px #aab9f4;      /*当鼠标放在按钮上个时边框的阴影*/
    box-shadow: inset 0px 1px 0px #aab9f4;
    margin-top:22px;
}