/* --- デザインの一貫性を保つための共通スタイル --- */
:root {
    --primary-blue: #5dade2; 
    --light-blue: #ebf5fb;
    --accent-orange: #f39c12;
    --text-dark: #333;
    --text-muted: #666;
    --bg-white: #ffffff;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    background-color: #f8f9fa;
    color: var(--text-dark);
    line-height: 1.6;
}

/* --- ヘッダー・ナビゲーション（共通構造 [1]） --- */
header { background-color: var(--bg-white); text-align: center; padding: 20px 10px; }
.lab-logo { font-size: 2rem; font-weight: bold; color: #2e86c1; display: flex; flex-direction: column; align-items: center; }

nav { background-color: var(--primary-blue); position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 5px rgba(0,0,0,0.1); }
.nav-container { max-width: 1000px; margin: 0 auto; display: flex; justify-content: center; }
.nav-menu { list-style: none; display: flex; }
.nav-item { position: relative; }
.nav-item > a { display: block; padding: 15px 20px; color: white; text-decoration: none; font-weight: bold; }
.nav-item:hover > a { background-color: #3498db; }

/* サブメニューの実装 [2] */
.submenu { display: none; position: absolute; top: 100%; left: 0; background-color: #fdfefe; min-width: 220px; box-shadow: 0 8px 16px rgba(0,0,0,0.1); list-style: none; border-top: 2px solid var(--primary-blue); }
.nav-item:hover .submenu { display: block; }
.submenu li a { padding: 12px 15px; display: block; color: var(--text-dark); text-decoration: none; font-size: 0.9rem; border-bottom: 1px solid #eee; }
.submenu li a:hover { background-color: var(--light-blue); }

/* --- メインコンテンツ --- */
.container { max-width: 1000px; margin: 30px auto; background: white; padding: 40px; box-shadow: 0 0 10px rgba(0,0,0,0.05); border-radius: 4px; }
.section-title { font-size: 1.5rem; color: var(--text-dark); border-left: 6px solid #d4e6f1; padding-left: 15px; margin-bottom: 25px; }

.intro-text { margin-bottom: 30px; color: var(--text-muted); }

/* 写真配置エリア */
.photo-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 40px;
    margin-top: 40px;
}

.photo-container {
    text-align: center;
}

.photo-container img {
    width: 460px;
    height: 330px;
    object-fit: cover;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    border: 5px solid white;
}

.photo-caption {
    margin-top: 15px;
    font-weight: bold;
    color: var(--primary-blue);
    font-size: 1.1rem;
}

.atmosphere-desc {
    max-width: 460px;
    margin: 10px auto 0;
    font-size: 0.9rem;
    color: var(--text-muted);
    text-align: left;
}

footer { text-align: center; padding: 30px; font-size: 0.8rem; color: var(--text-muted); border-top: 1px solid #eee; }

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .nav-menu { flex-direction: column; width: 100%; }
    .submenu { position: static; box-shadow: none; background-color: #f0f8ff; }
    .container { margin: 10px; padding: 20px; }
    .photo-container img {
        width: 100%; /* モバイルでは横幅いっぱい */
        height: auto;
    }
}