.login-box a {
    margin: auto;
    color: #fff;
    text-align: center;
}

.login-box .user-box {
    position: relative;
}

.login-box .user-box input {
    width: 100%;
    padding: 10px 0;
    font-size: 16px;
    color: #fff;
    margin-bottom: 30px;
    border: none;
    border-bottom: 1px solid #fff;
    outline: none;
    background: transparent;
}

.login-box .user-box label {
    position: absolute;
    top: 0;
    left: 0;
    padding: 10px 0;
    font-size: 16px;
    color: #fff;
    pointer-events: none;
    transition: 0.5s;
}

.login-box .user-box input:focus ~ label,
.login-box .user-box input:valid ~ label {
    top: -20px;
    left: 0;
    color: #4db150;
    font-size: 12px;
}

.login-box form a {
    position: relative;
    display: inline-block;
    padding: 10px 20px;
    color: #f6f6f6;
    font-size: 16px;
    text-decoration: none;
    text-transform: uppercase;
    overflow: hidden;
    transition: 0.5s;
    margin-top: 40px;
    letter-spacing: 4px;
}

.login-box a:hover {
    background: #4db150;
    color: #fff;
    border-radius: 5px;
    box-shadow: 0 0 5px #4db150, 0 0 25px #4db150, 0 0 50px #4db150,
            0 0 100px #4db150;
}

.login-box a span {
    position: absolute;
    display: block;
}

.login-box a span:nth-child(1) {
    top: 0;
    left: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, transparent, #4db150);
    animation: btn-anim1 1s linear infinite;
}

@keyframes btn-anim1 {
    0% {
            left: -100%;
    }

    50%,
    100% {
            left: 100%;
    }
}

.login-box a span:nth-child(2) {
    top: -100%;
    right: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(180deg, transparent, #4db150);
    animation: btn-anim2 1s linear infinite;
    animation-delay: 0.25s;
}

@keyframes btn-anim2 {
    0% {
            top: -100%;
    }

    50%,
    100% {
            top: 100%;
    }
}

.login-box a span:nth-child(3) {
    bottom: 0;
    right: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(270deg, transparent, #4db150);
    animation: btn-anim3 1s linear infinite;
    animation-delay: 0.5s;
}

@keyframes btn-anim3 {
    0% {
            right: -100%;
    }

    50%,
    100% {
            right: 100%;
    }
}

.login-box a span:nth-child(4) {
    bottom: -100%;
    left: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(360deg, transparent, #4db150);
    animation: btn-anim4 1s linear infinite;
    animation-delay: 0.75s;
}

@keyframes btn-anim4 {
    0% {
            bottom: -100%;
    }

    50%,
    100% {
            bottom: 100%;
    }
}

.main {
    position: absolute;
    display: block;
    width: 648px;
    height: 200px;
    background-color: #313131;
    top: 50%;
    left: 50%;
    margin: -92.5px 0 0 -324px;
    border-style: solid;
    border-width: 0px;
    border-color: black;
    border-radius: 10px;
    box-shadow: 0 0 10px 10px rgba(0,0,0,.3);
    z-index: 100;
}

img {
    position: fixed;
    top: 50%;
    left: 50%;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
    z-index: -100;
    transform: translateX(-50%) translateY(-50%);
    background-size: cover;
    transition: 1s opacity;
    filter: blur(3px);
}