.has-back .head-sub {
    padding: 100px 5% 0;
    display: flex;
    align-items: center;
    justify-content: flex-start;
}

@media screen and (min-width: 768px) {
    .has-back .head-sub {
        width: 66.7%;
        margin: 0 auto;
        padding: 50px 0 0;
    }
}

.has-back .common-head {
    padding-top: 40px;
    padding-bottom: 52px;
}

@media screen and (min-width: 768px) {
    .has-back .common-head {
        padding-top: 70px;
        padding-bottom: 120px;
    }
}

.has-back .btn-back {
    background: #fff;
    display: flex;
    align-items: center;
    padding: 8px 18px;
    border-radius: 100px;
    transition: background .3s;
}

.has-back .btn-back .arw {
    transform: rotate(90deg);
    margin-right: 12px;
}

.has-back .btn-back .arw svg {
    width: 9px;
    height: 12px;
    transition: transform .3s, opacity .3s;
}

.has-back .btn-back .arw svg:last-child {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    transform: translateY(-10px);
    fill: #fff;
}

.has-back .btn-back .t {
    position: relative;
}

.has-back .btn-back .t span {
    font-size: 1.2rem;
    letter-spacing: .05rem;
    transition: transform .3s, opacity .3s;
}

.has-back .btn-back .t span:last-child {
    position: absolute;
    top: 0;
    left: 0;
    text-align: center;
    opacity: 0;
    transform: translateY(10px);
    color: #fff;
}

@media screen and (min-width: 768px) {
    .has-back .btn-back {
        padding: 10px 26px;
    }

    .has-back .btn-back .arw {
        margin-right: 16px;
    }

    .has-back .btn-back .t span {
        font-size: 1.3rem;
        letter-spacing: .1rem;
    }

    .has-back .btn-back:hover {
        background: #333;
    }

    .has-back .btn-back:hover .arw svg {
        opacity: 0;
        transform: translateY(10px);
    }

    .has-back .btn-back:hover .arw svg:last-child {
        opacity: 1;
        transform: translateY(0);
    }

    .has-back .btn-back:hover .t span {
        opacity: 0;
        transform: translateY(-10px);
    }

    .has-back .btn-back:hover .t span:last-child {
        opacity: 1;
        transform: translateY(0);
    }
}

.has-back .series-purpose {
    background: #fff;
    padding: 38px 5%;
    margin-bottom: 28px;
    text-align: center;
}

.has-back .series-purpose strong {
    display: block;
    font-size: 2.6rem;
    letter-spacing: 0;
    font-weight: 700;
}

@media screen and (min-width: 768px) {
    .has-back .series-purpose {
        padding: 50px 8.4%;
        margin-bottom: 30px;
    }

    .has-back .series-purpose strong {
        font-size: 3.6rem;
        letter-spacing: .6rem;
    }
}