.btn-neon{
    align-items: center center;
    background: #ff7070;
    border-radius: 20px;
    
    position: relative;
    justify-content: center;
    display: flex;
    padding: 5px 5px;
    color: rgb(255, 255, 255);
    
    text-decoration: none;
    font-size: 18px;
    overflow: hidden;
    transition: 0.2s;
}
.btn-neon:hover{
    background: #0cdde4;
    box-shadow: 0 0 10px #00f7ff, 0 0 40px #00f7ff, 0 0 80px #00f7ff;
    transition-delay: 1s;
 }
.btn-neon span{
    position: absolute;
    display: block;
}
#span1{
    top: 0;
    left: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, transparent,#00f7ff);
 }
 .btn-neon:hover #span1{
    left: 100%;
    transition: 1s;
}
 #span3{
    bottom: 0;
    right: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(270deg, transparent,#00f7ff);
}
 .btn-neon:hover #span3{
    right: 100%;
    transition: 1s;
    transition-delay: 0.5s;
}
#span2{
    top: -100%;
    right: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(180deg,transparent,#00f7ff);
}
.btn-neon:hover #span2{
    top: 100%;
    transition: 1s;
    transition-delay: 0.25s;
}
#span4{
    bottom: -100%;
    left: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(360deg,transparent,#00f7ff);
}
.btn-neon:hover #span4{
    bottom: 100%;
    transition: 1s;
    transition-delay: 0.75s;
}