a {
    text-decoration: none;
}

.insta_btn {
    display: inline-block;
    text-align: center;
    /*中央揃え*/
    color: #3774ba;
    /*文字色*/
    /*    font-size: 20px;*/
    /*文字サイズ*/
    text-decoration: none;
    /*下線消す*/
}

.insta_btn:hover {
    /*ホバー時*/
    color: #72c8d5;
    /*文字色*/
    transition: .5s;
    /*ゆっくり変化*/
}

.twitter span {
    color: #3774ba;
}

.twitter span:hover {
    color: #284c9e;
    transition: .5s;
}

.youtube span{
    color: #3774ba;
}

.youtube span:hover {
    color: #e087b5;
    transition: .5s;
}