.m {
    background-color: #1B6568;
    color: white;
    padding: 40px;
    height: 800px;
}

.m2 {
    padding: 40px;
}

.triangle-right {
    width: 0;
    height: 0;
    border-top: 25px solid transparent;
    border-left: 50px solid #1B6568;
    border-bottom: 25px solid transparent;
    margin-top: 480px;
    margin-left: -20px;

}

@media screen and (min-width: 0px) and (max-width: 770px) {
    .triangle-right {
        display: none;
    }
}