html{
    height:100%;
}
body {
    margin: 0;
    padding: 0;
    font-family: sans-serif;
    background:linear-gradient(#141e30,#243b55);
    
}
:root{
    --main-color: #fff;
}
.login-box{
    position: absolute;
    top: 50%;
    left: 50%;
    width: 400px;
    padding: 40px;
    transform: translate(-50%,-50%);
    background: rgba(0,0,0,.5);
    box-sizing: border-box;
    box-shadow: 0 15px 25px rgba(0, 0,0,.6);
    border-radius: 10px;
}
.login-box h2{
    margin: 0 0 30px;
    color:var(--main-color);
    text-align: center;
}

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

}
.login-box .user-box label{
    position: absolute;
    top: 0;
    left: 0;
    padding: 10px 0;
    font-size: 16px;
    color: var(--main-color);
    pointer-events:none ;
    transition: .5s;
}
.login-box .user-box input:focus ~ label,
.login-box .user-box input:valid ~ label {
  top: -20px;
  left: 0;
  color: #03e9f4;
  font-size: 12px;
}
.login-box form a{
    position: relative;
    display: inline-block;
    padding: 11px 20px;
    color: #03e9f4;
    font-size: 16px;
    text-decoration: none;
    text-transform: uppercase;
    overflow: hidden;
    transition: .5s;
    margin-top: 40px;
    letter-spacing: 4px;

}
.login-box a:hover{
    background:#03e9f4 ;
    color: var(--main-color);
    border-radius: 5px;
    box-shadow: 0  0 5px #03e9f4,
                0  0 25px #03e9f4,
                0  0 50px #03e9f4,
                0  0 100px #03e9f4;
}
.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, #03e9f4);
    animation: 1s linear infinite;
    animation-name: btn-animl;
}
@keyframes btn-animl{
    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, #03e9f4);
    animation: btn-anim2 1s linear infinite;
    animation-delay: .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, #03e9f4);
    animation: btn-anim3 1s linear infinite;
    animation-delay: .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, #03e9f4);
    animation: btn-anim4 1s linear infinite;
    animation-delay: .75s
  }
  
  @keyframes btn-anim4 {
    0% {
      bottom: -100%;
    }
    50%,100% {
      bottom: 100%;
    }
  }