/* 全ページ共通のスタイル (デザイン統一版) */
@import url('https://fonts.googleapis.com/css?family=Roboto:wght@400;700&display=swap');

body {
    font-family: 'Roboto', 'Yu Gothic', 'Meiryo', sans-serif;
    background: linear-gradient(135deg, #e7f5ff 0%, #ffffff 100%);
    background-attachment: fixed;
    margin: 0;
    padding-top: 70px; /* 固定ヘッダー分の余白 */
    padding-left: 10px;
    padding-right: 10px;
    color: #3a4a5b;
}

/* --- ナビゲーションバー --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: linear-gradient(90deg, #ffffff 0%, #e7f5ff 100%);
    box-shadow: 0 2px 8px rgba(60, 143, 214, 0.1);
    padding: 10px 0;
    border-bottom: 1px solid #c6e7ff;
}

.nav-container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-family: 'Courier New', Courier, monospace;
    font-weight: bold;
    font-size: 1.8em;
    color: #2365b6;
    margin: 0;
}

.nav-links {
    margin: 0;
    padding: 0;
    list-style: none;
    display: flex;
    gap: 10px;
}

.nav-links li a {
    display: block;
    text-decoration: none;
    color: #fff;
    background: linear-gradient(90deg, #1976d2 0%, #73bbfa 100%);
    padding: 8px 18px;
    border-radius: 18px;
    font-size: 0.85em;
    font-weight: bold;
    border: 2px solid #73bbfa;
    transition: all 0.2s ease;
    box-shadow: 0 1px 6px rgba(25, 118, 210, 0.2);
}

.nav-links li a:hover {
    background: linear-gradient(90deg, #ffffff 0%, #e7f5ff 100%);
    color: #1976d2;
    border-color: #1976d2;
    transform: translateY(-2px);
}

/* --- 基本的なコンテンツコンテナ --- */
.container {
    width: 80%;
    max-width: 940px;
    margin: 40px auto;
    padding: 30px 40px;
    background: linear-gradient(108deg, #ffffff 80%, #e7f5ff 100%);
    border-radius: 16px;
    box-shadow: 0 4px 14px rgba(60, 143, 214, 0.1), 0 1px 6px rgba(198, 231, 255, 0.2);
    border: 2px solid #c6e7ff;
}

h1, h2, h3 {
    color: #2365b6;
    font-weight: bold;
}

h1 {
    font-size: 2.5em;
    text-align: center;
    margin-bottom: 30px;
    text-shadow: 0 2px 11px rgba(60, 143, 214, 0.1);
}

h2 {
    font-size: 1.6em;
    border-left: 7px solid #1976d2;
    padding-left: 15px;
    margin-bottom: 20px;
    background: linear-gradient(90deg, #e7f5ff 70%, #fff 100%);
    padding-top: 8px;
    padding-bottom: 8px;
    border-radius: 0 8px 8px 0;
}

a, a:hover, a:visited {
    color: inherit;
    text-decoration: none;
}

footer {
    text-align: center;
    padding: 20px;
    margin-top: 40px;
    background: #e7f5ff;
    color: #2365b6;
    border-top: 1px solid #c6e7ff;
}

/* --- レスポンシブ対応 --- */
@media (max-width: 768px) {
    body {
        padding-top: 120px;
    }
    .nav-container {
        flex-direction: column;
        gap: 15px;
    }
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    .container {
        width: 95%;
        padding: 20px;
    }
    h1 {
        font-size: 1.8em;
    }
    h2 {
        font-size: 1.3em;
    }
}