.main-button.-about{
    position: relative;
    top: 90px;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50px;
    height: 50px;
    margin: 30px;
    cursor: pointer;
    border: none;
}

.main-button.-about::before{
    display: block;
    width: 15px;
    height: 15px;
    content: '';
    box-sizing: border-box;
    border: 15px solid transparent;
    border-right: 28px solid #fff;
    transform: translateX(-9px);
}

.main-button.-about.-right::before{
    transform: rotate(180deg) translateX(-9px);
}

.main-button.-about .content{
    display: none;
}