.back-top {
    background: url('../img/otona/back_top@2x.png');
    background-size: contain;
    background-position: center;
    background-repeat: no-repeat;
}


.button-container {
    max-width: 1024px;
    height: 100px;
    margin: 0 auto;
    margin-top: 70px;
    justify-content: center
}

.button {
    width: 15%;
    height: auto;
    margin: 0px 20px 0px 20px;
}

.header-btn {
    width: 95%;
    height: auto;
}

.spacer {
    flex-grow: 1; /* 中央の空白部分を最大化 */
}

/*
タブレット用
*/
@media screen and (max-width: 1024px) {
    .button {
        margin: 0px 20px 0px 20px;
    }

    /* .header-btn {
        width: 13vw;
        height: auto;
    } */
}

/*
スマホ用
375px ～を想定
*/
@media screen and (max-width: 768px) {

    .header-title {
        top:60px;
    }

    .button-container {
        justify-content: space-between; 
        width: 98%;
        margin-top: 30px;
    }

    .button {
        margin: 0;
        padding: 0;
        text-align: center;
    }

    .button {
        width: 30%;
        height: auto;
    }

    .back-top {
        position: fixed;
        bottom: 50px;
        z-index: 999;
        right: 30px;
    }
    
    .back-top > img {
        width: 80px;
        height: auto;
    }

}