body{
    margin: 0;
    padding: 0;
 
    justify-content: center;
    align-items: center;
    
    
    font-family:consolas;
}
.btn-neon{
    position: relative;
    display: inline-block;
    padding: 15px 30px;
    color: rgb(240, 101, 9);
    border-radius: 30px;  /*para hacer curva los margenes*/
    letter-spacing: 4px;
    text-decoration: none;
    font-size: 24px;
    overflow: hidden;
    transition: 0.1s;
}
.btn-neon:hover{
    background: #2C3E50;
    box-shadow: 0 0 10px #34495E, 0 0 40px #34495E, 0 0 80px #34495E;
    transition-delay: 0.1s;
 }
.btn-neon span{
    position: absolute;
    display: block;
}
#span1{
    top: 0;
    left: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, transparent,#100114);
 }
 .btn-neon:hover #span1{
    left: 100%;
    transition: 0.05s; /*para que la linea vaya más rapido*/
}
 #span3{
    bottom: 0;
    right: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(270deg, transparent,#0c010f);
}
 .btn-neon:hover #span3{
    right: 100%;
    transition: 0.25s;
    transition-delay: 0.15s;
}
#span2{
    top: -100%;
    right: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(180deg,transparent,#09000c);
}
.btn-neon:hover #span2{
    top: 100%;
    transition: 0.15s;
    transition-delay: 0.060s;
}
#span4{
    bottom: -100%;
    left: 0;
    width: 2px;
    height: 100%;
    background: linear-gradient(360deg,transparent,#08000a);
}
.btn-neon:hover #span4{
    bottom: 100%;
    transition: 0.15s;
    transition-delay: 0.15s;
}