.pulse-button {
    position: fixed;
    display: block;
    width: 3em;
    height: 3em;
    font-size: 1.3em;
    color: #fff;
    text-shadow: 0 1px 0 #1f4c76;
    border: none;
    box-shadow: 0 0 0 0 rgba(90, 153, 220, 0.7), inset 0 1px 0 #abcbe9;
    border-radius: 100%;
    background: #fff;
    cursor: pointer;
    background-repeat: no-repeat;
    background-size: 3em 3em;
    animation: pulse 1s infinite cubic-bezier(0.6, 0, 0, 1);
    margin-left: -5px;
    margin-top: -20px;
}

.pulse-button-telegram {
    background-image: url(https://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Telegram_logo.svg/2048px-Telegram_logo.svg.png);
}

.pulse-button-whatsapp {
    background-image: url(https://deli-yug.ru/wp-content/uploads/2020/04/whatsapp.png);
}

@keyframes pulse {
    to {
        box-shadow: 0 0 0 15px rgba(90, 153, 220, 0), inset 0 1px 0 #abcbe9;
    }
}

@media (max-width: 980px) {
    .pulse-button {
        width: 3em;
        height: 3em;
        background-size: 3em 3em;
    }
}