.click_me {
    position: relative;
    display: inline-block;
    padding: 25px 30px;
    margin: 40px 0;
    color: #03e9f4;
    text-decoration: none;
    text-transform: uppercase;
    letter-spacing: 4px;
    font-weight: bold;
    background: transparent;
    border-radius: 12px;
    overflow: hidden;
    cursor: pointer;
    transition: 0.3s ease-in-out;
}

.click_me::before {
    content: "";
    position: absolute;
    inset: 0;
    border-radius: 12px;
    padding: 2px;
    /* spessore del bordo */
    background: linear-gradient(90deg,
            transparent,
            #03e9f4,
            transparent);
    mask: /* Firefox */
        linear-gradient(#fff 0 0) content-box,
        linear-gradient(#fff 0 0);
    mask-composite: exclude;

    -webkit-mask: /* Chrome/Edge/Safari */
        linear-gradient(#fff 0 0) content-box,
        linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;

    mask-composite: exclude;
    animation: border-rotate 4s linear infinite;
}

.click_me:hover {
    color: #050801;
    background: #03e9f4;
    box-shadow: 0 0 10px #03e9f4, 0 0 15px #03e9f4, 0 0 45px #03e9f4;
}

@keyframes border-rotate {
    0% {
        background-position: 0% 50%;
    }

    100% {
        background-position: 400% 50%;
    }
}