*, *:before, *:after {
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

html {
    /* ルートのフォントサイズを10pxに設定しておく */
    font-size: 62.5%;
}

body {
    /* ルートのフォントサイズを1.6em（16pxと同等のサイズ）に設定 */
    font-size: 2em;
    width: 100%;
    font-family:"ヒラギノ丸ゴ Pro W4", "ヒラギノ丸ゴ Pro", "Hiragino Maru Gothic Pro", "HG丸ｺﾞｼｯｸM-PRO", "HGMaruGothicMPRO";
}

header {
    width: 100%;
    margin-bottom: 2rem;
}

.inner {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    margin-left: -1em;
    padding-top: 1em;
    padding-bottom: 1em;
}

.header_img {
    margin-left: 1em;
}

.header_img img {
    width: 60px;
    height: auto;
}

.header_title {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    margin-left: 1em;
    -ms-flex-wrap: wrap;
        flex-wrap: wrap;
}

#edition {
    font-size: 1.6rem;
    margin-bottom: .5rem;
    margin-right: 1.6rem;
    color: #fff;
}

#catchcopy {
    font-size: 1.6rem;
    margin-bottom: .5rem;
    color: #fff;
}

#book_title {
    font-size: 2.4rem;
    margin-bottom: .5rem;
    width: 100%;
    font-weight: bold;
    color: #fff;
}

.nav_wrapper {
    margin-bottom: 3rem;
}

.other_book {
    display: block;
    font-size: 1.6rem;
    width: 100%;
    margin: 0 auto 1.5rem;
    background-color: #fff;
    border: solid 3px #6c757d;
    color: #6c757d;
}

.other_book:hover{
    background-color: #6c757d;
    color: #fff;
}

.caution{
    text-align: center;
    margin-bottom: 1.5rem;
}

.caution a{
    font-size: 1.6rem;
    text-decoration: underline;
    color: #000;
}

.caution a:before, .caution a:after {
    content: "";
    background-color: #000;
    border-radius: 50%;
    display: inline-block;
    height: 1rem;
    width: 1rem;
    margin: 0 .5rem;
}

.caution a:hover{
    color: rgb(246, 170, 0);
}

.preparation p {
    text-align: center;
}

.unitlist_wrapper {
    margin-bottom: 2rem;
}

.index {
    margin-bottom: 1rem;
}

.table {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    list-style: none;
    padding: 0 1rem;
    margin-bottom: 1.5rem;
}

.card-header-expand {
    margin-bottom: 1rem;
    color: #fff;
}

.table li {
    width: 100%;
    margin-bottom: .6rem;
}

.table li:before {
    content: ">";
    font-weight: bold;
    font-size: 1.8rem;
    color: gray;
    padding-right: .5rem;
}

.table li a {
    color: #000;
    font-size: 1.8rem;
    border-bottom: solid 1px #000;
}

.table li a:hover {
    text-decoration: none;
    color: rgb(246, 170, 0);
    border-bottom: solid 1px rgb(246, 170, 0);
}

.font-smaller {
    font-size: .7em;
}

.unit {
    margin-bottom: 1.5rem;
}

.unit_title {
    color: #fff;
    text-align: center;
    margin-bottom: 1.5rem;
}

.contents_list {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    justify-content: space-between;
}

.content {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
    padding: 1rem;
    -webkit-box-shadow: 0px .2rem rgba(0,0,0,.5);
            box-shadow: 0px .2rem rgba(0,0,0,.5);
    text-decoration: none;
    color: #000;
    width: 100%;
}

.content:hover {
    text-decoration: none;
    color: #000;
    -webkit-transition: .15s;
    transition: .15s;
    -webkit-box-shadow: none;
            box-shadow: none;
    -webkit-transform: translate3d(0, .2rem, 0);
            transform: translate3d(0, .2rem, 0);
}

.content_img {
    width: 20%;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
}

.content_img img {
    width: 100%;
    height: auto;
    max-width: 50px;
}

.content_text {
    width: 80%;
    padding-left: 1rem;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
}

.page_no {
    text-align: left;
    font-size: 1.6rem;
    margin-bottom: 0;
}

.content_title {
    margin-bottom: 0;
}

.pagetop {
    position: fixed;
    bottom: 1rem;
    right: 1rem;
    text-decoration: none;
    opacity: 0.6;
}

.pagetop img {
    width: 50px;
    height: 50px;
}

.pagetop:hover {
    opacity: 1;
}

footer {
    padding: .5rem 2rem;
    background-color: rgb(206, 206, 206);
}

footer p {
    font-size: 1.2rem;
    margin: 0;
}

/* 書籍ごとのカラー定義 */

/* 幾何 */

.kika_theme-bg {
    background-color: rgb(0, 160, 112);
}


.kika_unit-bg {
    background-color: rgb(0, 160, 112);
}


.kika_content-bg {
    background-color: rgb(191, 231, 200);
}

.kika_content-bg:hover {
    background-color: rgb(113, 197, 117);
    color: #fff;
}

/* 代数 */

.daisu_theme-bg {
    background-color: rgb(68, 114, 196);
}

.daisu_unit-bg {
    background-color: rgb(68, 114, 196);
}

.daisu_content-bg {
    background-color: rgb(189, 215, 238);
}

.daisu_content-bg:hover {
    background-color: rgb(142, 186, 226);
    color: #fff;
}

/* 幾何2 */

.kika2_theme-bg {
    background-color: rgb(205, 87, 79);
}


.kika2_unit-bg {
    background-color: rgb(205, 87, 79);
}


.kika2_content-bg {
    background-color: rgb(247, 210, 208);
}

.kika2_content-bg:hover {
    background-color: rgb(242, 162, 157);
    color: #fff;
}

/* 代数2 */

.daisu2_theme-bg {
    background-color: rgb(220, 102, 19);
}

.daisu2_unit-bg {
    background-color: rgb(220, 102, 19);
}

.daisu2_content-bg {
    background-color: rgb(240, 182, 141);
}

.daisu2_content-bg:hover {
    background-color: rgb(240, 199, 141);
    color: #fff;
}

/*bootstrapブレークポイントxs(543pxまで）をベースに作成*/

/*sm（544px以上）*/

@media screen and (min-width: 544px) {
    /*フォントサイズを1.5倍にする*/
    html {
        font-size: 93.75%;
    }
    .header_img img {
        width: 100px;
        height: auto;
    }
    .content_img img {
        width: 100%;
        height: auto;
        max-width: 80px;
    }
}

/*md（768px以上）*/

@media screen and (min-width: 768px){
    .table li {
        width: 50%;
    }    

}


/*lg（992px以上）*/

@media screen and (min-width: 992px) {
    /*フォントサイズを2倍にする*/
    html {
        font-size: 125%;
    }
    .header_img img {
        width: 120px;
        height: auto;
    }
    .content {
        width: 48%;
        padding: .5rem;
    }
    .content_img img {
        width: 100%;
        height: auto;
    }
    .page_no {
        font-size: 1rem;
    }
    .content_title {
        font-size: 1.5rem;
    }
}