@charset "utf-8";
    *, *::before, *::after {
        box-sizing: border-box;
    }
    html {
        scroll-behavior: smooth;
    }
    body {
        color: #333333;
        font-family: 'Sawarabi Gotric', sans-serif;
        line-height: 2;
    }       
    h2 {
        border-bottom: 3px solid lightsteelblue;
    }
    h1, h2 {
        text-align: center;
    }
    .header {
        text-align: center;
        background: navy;
        color: orange;
    }
    .header p {
        margin: 0;
    }
    .icatch {
        text-align: center;
    }
    section:nth-child(odd) {
        background: lightsteelblue;
    }
    section:nth-child(odd) h2 {
        border-bottom: 3px solid white;
    }
    .summary dd {
        border-bottom: 1px dotted white;
        padding-bottom: 8px;
    }
    .card-body {
        margin-bottom: 20px;
    }
    .big_list {
        padding-left: 1rem;
        font-weight: bold;
        display: block;
        margin: 0 auto;
    }
    .button {
        text-align: center;
    }
    footer {
        text-align: center;
        position: relative;
        background: seagreen;
        margin-top: 100px;
    }
    .footer_copyright {            
        text-align: center;
        color: white;
    }
    .footer_text {
        margin-bottom: 0;
    }
    .footer_text a {
        color: white;
        text-decoration: none;
    }
    small {
        font-size: 1rem;
    }
    .gotop {
        position: absolute;
        top: -60px;
        right: 0px;
        background: lightseagreen;
        padding: 10px 18px;
        border-radius: 50%;
        border: 5px solid seagreen;          
    }
    .gotop a::before {
        content: '';
        width: 1.8em;
        height: 1.8em;
        border-left-width: 0;
        border-bottom-width: 0;
        border-top: 5px solid white;
        border-right: 5px solid white;
        position: absolute;
        -webkit-transform: translateY(-80%) rotate(-45deg);
        transform: translateY(-80%) rotate(-45deg);
        top: 77%;
        right: 0.75em;
        pointer-events: none;
    }
    .gotop a {
        color: white;
        text-decoration: none;
        display: block;
    }
    .gotop:hover,
    .gotop:focus {
        background: lightgreen;
    }

    /* mobile */
    h1 {
        font-size: 1.2rem;
    }
    h2 {
        font-size: 1.2rem;
        margin-bottom: 20px;
        padding-bottom: 10px;
    }
    h3 {
        font-size: 1rem;
        margin: 15px 0 10px;
        padding-left: 10px;
        border-left: 10px solid orange;
    }
    header {
        padding: 20px 10px;
    }
    section {
        padding: 40px 10px;
    }
    footer {
        padding: 20px 0 20px;
    }
    .big_list {
        font-size: 1rem;
    }
    .youtube {
        width: 100%;
    }
    /* tablet */
    @media screen and (min-width: 48em) {
        h1 {
        font-size: 2rem;
        }
        h2 {
        font-size: 1.2rem;
        margin-bottom: 15px;
        padding-bottom: 10px;
        }
        h3 {
        font-size: 1rem;
        margin: 20px 0 15px;
        padding-left: 15px;
        border-left: 10px solid orange;
        }
        header {
        padding: 20px 0;
        }
        section {
        padding: 50px 25px;
        }
        footer {
        padding: 25px 0 25px;
        }
        .article_images dd img {
        width: 60%;
        }
        .big_list {
        font-size: 1.15rem;
        }
        .youtube {
        width: 60%;
        }
    }
    /* laptop */
    @media screen and (min-width: 64em) {
        h1 {
        font-size: 2.3rem;
        }
        h2 {
        font-size: 1.5rem;
        margin-bottom: 30px;
        padding-bottom: 20px;
        }
        h3 {
        font-size: 1.2rem;
        margin: 30px 0 20px;
        padding-left: 15px;
        border-left: 10px solid orange;
        }
        header {
        padding: 30px 0;
        }
        section {
        padding: 60px 40px;
        }
        footer {
        padding: 30px 0 30px;
        }
        .article_images dd img {
        width: 40%;
        }
        .big_list {
        font-size: 1.25rem;
        }
        .youtube {
        width: 40%;
        }
    }