html{height: 100%;}
body.signin {
    background: #18c8f6;
    height: auto;
    background:url("../images/login-background.jpg") no-repeat center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    color: rgba(255,255,255,.95);
    padding-top: 120px; 
}
.signin .fa{
    width: 30px;
    font-size: 20px;
    color: #a2a1a8;
    position: absolute;
    left: 12px;
    top: 13px;
    padding-right: 12px;
    border-right: 1px solid #ddd;
}
.signin .fa-keyboard-o{
    left: 10px;
    width: 32px;
}

.loginscreen.middle-box{
    width: 400px;
    border: 5px solid rgba(0,0,0,0.15);
    background: #fcfcfc;
    padding: 0;
}
.loginscreen.middle-box h4{
    font-size: 22px; 
    font-family: Microsoft Yahei;
    font-weight: normal;
    color: #676767;
    height: 48px;
    line-height: 48px;
    border-bottom: 1px solid #dcdcdc;
    margin: 0;
}
.loginscreen.middle-box > div{ 
    padding: 20px 44px; 
}
.loginscreen.middle-box > div .m-t{ 
    margin: 0;
}
.loginscreen.middle-box > div .form-group{
    position: relative;
}
.loginscreen.middle-box > div input{
    color: #000;
    height: 46px;
    line-height: 46px;
    padding: 12px 12px 12px 50px;
}
.loginscreen.middle-box .code{
    position: absolute;
    right: 2px;
    top: 2px;
    height: 42px;
    width: 82px;
}
.loginscreen.middle-box .btn{
    font-size: 16px;
    height: 46px;
    line-height: 46px;
}