body {
    margin: 0;
    padding: 0;
    font-family: "游ゴシック体", "Yu Gothic", "ヒラギノ角ゴ ProN W3", "Hiragino Kaku Gothic ProN", "メイリオ", Meiryo, "MS ゴシック", "MS Gothic", sans-serif;
}

/* ===== ヘッダー ===== */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #fff;
    padding: 16px 32px;
    box-sizing: border-box;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.site-title {
    margin: 0;
    font-size: 1.8rem;
    text-align: left;
    cursor: pointer;
}

.site-title a {
    text-decoration: none;
    color: #000;
}

/* ===== ハンバーガーメニュー ===== */
.hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 36px;
    height: 36px;
    cursor: pointer;
    z-index: 1100;
}

.hamburger span {
    display: block;
    width: 27px;
    height: 3px;
    margin: 5px auto;
    background: #333;
    border-radius: 2px;
    transition: 0.3s;
}

/* ===== ナビゲーション ===== */
.site-nav {
    margin-left: auto;
    height: 100%;
    display: flex;
    align-items: center;
}

.nav-list {
    display: flex;
    gap: 24px;
    list-style: none;
    margin: 0;
    padding: 0;
    height: 100%;
}

.nav-list li a {
    text-decoration: none;
    color: #333;
    font-weight: bold;
    transition: color 0.2s;
    height: 100%;
    display: flex;
    align-items: center;
}

.nav-list li a:hover,
.here a {
    color: #399;
    border-bottom: solid 2px #399;
}

/* ===== メイン ===== */
main {
    width: 100%;
    margin-top: 80px;
}

/* ボタン共通スタイル */
button {
    background: #399;
    border: none;
    border-radius: 6px;
    color: #fff;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
    font-size: 1.1rem;
    margin-top: 12px;
    padding: 12px 32px;
    width: 240px;
    height: 55px;
    letter-spacing: 0.05em;
}

button:hover {
    background: #266;
    transform: translateY(-2px);
}

section {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    margin-top: 56px;
    margin-bottom: 56px;
}

section:first-of-type {
    margin-top: 0;
}

.section_title {
    font-size: 2rem;
    margin: 32px 0 16px 0;
    border-bottom: #399 2px solid;
    text-align: center;
}

section p {
    font-size: 1.1rem;
    margin-bottom: 24px;
    text-align: center;
    line-height: 1.7;
}

section img {
    max-width: 320px;
    width: 100%;
    margin-top: 24px;
}

section img.under_construction {
    max-width: 500px;
    width: 100%;
    height: auto;
    margin-top: 32px;
    margin-bottom: 16px;
    display: block;
    margin-left: auto;
    margin-right: auto;
}

/* #introductionセクション共通スタイル */
#introduction {
    padding: 40px 0 32px 0;
    margin-bottom: 48px;
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
}

#introduction>div {
    display: flex;
    flex-direction: row;
    gap: 32px;
    width: 50%;
    min-width: 320px;
    max-width: 700px;
    justify-content: center;
    margin-bottom: 24px;
}

#introduction p {
    font-size: 1.15rem;
    text-align: left;
    margin: 0;
    line-height: 1.8;
    color: #222;
    flex: 2;
}

#introduction img {
    margin-top: 0;
    width: 200px;
    height: 200px;
    border-radius: 15px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.10);
    background: #fff;
    object-fit: cover;
    flex: 1;
    min-width: 120px;
    max-width: 200px;
}

/* ===== フッター ===== */
footer {
    background: #222;
    color: #fff;
    text-align: center;
    padding: 32px 16px 24px 16px;
    margin-top: 10vw;
    font-size: 1rem;
    line-height: 1.8;
}

footer p {
    margin: 8px 0;
}

/* ===== レスポンシブ ===== */
@media (max-width: 900px) {
    #introduction>div {
        width: 70%;
        /* 修正: 7%だと小さすぎる */
        min-width: 0;
        max-width: 98vw;
        gap: 20px;
    }
}

@media (max-width: 600px) {
    .site-header {
        height: 56px;
        padding: 8px 12px;
    }

    .site-title {
        font-size: 1.3rem;
    }

    .site-nav {
        display: none;
        position: fixed;
        top: 56px;
        right: 0;
        width: 70vw;
        max-width: 320px;
        height: calc(100vh - 56px);
        background: #fff;
        box-shadow: -2px 0 8px rgba(0, 0, 0, 0.08);
        flex-direction: column;
        align-items: flex-start;
        padding: 32px 0 0 0;
        z-index: 1050;
        transition: transform 0.3s;
    }

    .nav-list {
        flex-direction: column;
        gap: 0;
        width: 100%;
        height: auto;
    }

    .nav-list li {
        width: 100%;
    }

    .nav-list li a {
        margin: 12px 0;
        padding: 0 24px;
        font-size: 1.1rem;
        border-bottom: 1px solid #eee;
        text-align: left;
    }

    .hamburger {
        display: flex;
    }

    #nav-toggle:checked~.site-header .site-nav,
    #nav-toggle:checked~.site-header nav.site-nav {
        display: flex;
    }

    #nav-toggle:checked~.site-header .hamburger span:nth-child(1) {
        transform: translateY(12px) rotate(45deg);
    }

    #nav-toggle:checked~.site-header .hamburger span:nth-child(2) {
        opacity: 0;
    }

    #nav-toggle:checked~.site-header .hamburger span:nth-child(3) {
        transform: translateY(-12px) rotate(-45deg);
    }

    main {
        margin-top: 56px;
    }

    section {
        margin: 32px 0 36px 0;
        padding: 0 24px;
    }

    .section_title {
        font-size: 1.2rem;
    }

    section img {
        max-width: 100%;
    }

    section img.under_construction {
        max-width: 70vw;
        margin-top: 24px;
        margin-bottom: 12px;
    }

    section p {
        font-size: 0.9rem;
        width: 80%;
    }

    button {
        width: 100%;
        font-size: 1rem;
        height: 44px;
        padding: 10px 32px;
    }

    footer {
        font-size: 0.9rem;
    }

    /* #introductionセクション レスポンシブスタイル */
    #introduction {
        padding: 24px 0 20px 0;
        margin-bottom: 32px;
    }

    #introduction>div {
        flex-direction: column;
        align-items: center;
        width: 70%;
        gap: 12px;
    }

    #introduction img {
        margin-top: 12px;
        width: 150px;
        height: 150px;
        max-width: 140px;
        border-radius: 12px;
    }

    #introduction p {
        width: 100%;
        font-size: 0.9rem;
    }
}