*{
    margin: 0;
    padding: 0;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    box-sizing: border-box;
    text-decoration: none;
}
.wrapper{
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #000;
}
a{
    position: relative;
    display: inline-block;
    padding: 25px 30px;
    text-transform: uppercase;
    letter-spacing: 4px;
    color: #03e9f4;
    font-size: 1.2rem;
    font-weight: bold;
    transition: .5s;
    overflow: hidden;
    margin-right: 70px;
}
a:hover{
    background-color: #03e9f4;
    color: #050801;
    box-shadow:0 0 5px #03e9f4,
               0 0 25px #03e9f4,
               0 0 50px #03e9f4,
               0 0 200px #03e9f4;
    -webkit-box-reflect:below 1px linear-gradient(transparent,#0005) ;

}
a:first-child{
    filter:hue-rotate(225deg)
}
a:last-child{
    filter: hue-rotate(90deg);
}
a span{
    position: absolute;
    display: block;
}
a span:nth-child(1){
    top: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg,transparent,#03e9f4);
    animation: animate1 1s infinite;
}
@keyframes animate1{
    0%{
        left: -100%;
    }
    100%{
        left: 100%;
    }
}
a span:nth-child(2){
    top: -100%;
    right: 0;
    width: 1px;
    height: 100%;
    background: linear-gradient(180deg,transparent,#03e9f4);
    animation: animate2 1s infinite;
    animation-delay:.25s ;
}
@keyframes animate2{
    0%{
        top: -100%;
    }
    100%{
        top: 100%;
    }
}
a span:nth-child(3){
    bottom: 0;
    right: 0;
    width: 100%;
    height: 1px;
    background:linear-gradient(270deg,transparent,#03e9f4) ;
    animation:animate3 1s infinite ;
    animation-delay:.5s;

}
@keyframes animate3 {
    0%{
        right: -100%;
    }
    100%{
        right: 100%;
    }

}
a span:nth-child(4){
    bottom:-100%;
    left: 0;
    width: 1px;
    height: 100%;
    background:linear-gradient(360deg,transparent,#03e9f4) ;
    animation:animate4 1s infinite ;
    animation-delay:.75s;
}
@keyframes animate4 {
    0%{
        bottom: -100%;
    }
    100%{
        bottom: 100%;
    }

}