/* ======================
 common
====================== */
main > picture img,
section ul img,
aside ul img {
    width: 100%; /* 見出し以外の画像を幅100%に指定 */
}
section,
aside {
    margin: 0 5%;
}
section > picture img,
aside > picture img {
    display: block;
    margin: 100px auto 50px;
}
section ul {
    display: flex;
    justify-content: space-between;
}

/* ======================
 aside
====================== */
aside ul img {
    margin: 0 10% 25px;
    width: 80%;
}

/* ======================
 link_list
====================== */
.link_list {
    margin: 50px 5% 100px;
}
.link_list ul li {
    background-color: rgba(231,37,73,0.5);
    width: 49%;
}
.link_list ul li img {
    display: block;
    margin: 0 auto;
    padding: 50px 0;
    width: 70%;
}

/* =============================
 Media Queries
============================= */
@media screen and (max-width:768px){
    section > picture img,
    aside > picture img {
        margin: 50px auto 25px;
    }
    section ul,
    .link_list ul {
        flex-wrap: wrap;
    }
    section ul li {
        width: 50%;
    }
    section ul img {
        width: 100%;
    }
    aside ul img {
        margin: 0 0 25px;
        width: 100%;
    }
    .link_list ul li {
        width: 100%;
    }
    .link_list ul li:first-of-type {
        margin-bottom: 25px;
    }
}