@charset "UTF-8";

/* --- 共通設定 --- */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", sans-serif;
    line-height: 1.8;
    color: #333;
    background-color: #f8f9fa;
}

/* --- レイアウト --- */
#wrapper {
    max-width: 1000px;
    margin: 0 auto;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

/* --- ヘッダー --- */
header {
    background-color: #2c5e6b;
    color: #fff;
    padding: 40px 20px;
    text-align: center;
}

/* --- ナビゲーション --- */
nav {
    background-color: #4a90a4;
    position: sticky;
    top: 0;
    z-index: 100;
}
nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
}
nav ul li a {
    display: block;
    padding: 15px 20px;
    color: #fff;
    text-decoration: none;
    transition: 0.3s;
}
nav ul li a:hover {
    background-color: #3a7585;
}

/* --- メインコンテンツ --- */
main {
    padding: 40px 20px;
}
section {
    margin-bottom: 50px;
}
h2 {
    border-bottom: 2px solid #2c5e6b;
    padding-bottom: 10px;
    margin-bottom: 20px;
    color: #2c5e6b;
}

.image-practice {
    background-color: #eef9fb;
    border: 2px dashed #4a90a4;
    padding: 20px;
    text-align: center;
    margin: 20px 0;
}
.image-practice img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}
th, td {
    border: 1px solid #ddd;
    padding: 12px;
    text-align: left;
}
th { background-color: #f2f2f2; }

/* --- フッター --- */
footer {
    background-color: #333;
    color: #fff;
    padding: 30px 20px;
    text-align: center;
}

/* --- レスポンシブ対応 --- */
@media screen and (max-width: 600px) {
    nav ul { flex-direction: column; text-align: center; }
    header { padding: 20px 10px; }
}