/* 起動ボタン */
.open-btn { 
    padding: 12px 24px; 
    cursor: pointer; 
    background: none; 
    color: #ccc; 
    border: 1px solid #333; 
    transition: 0.3s; 
    letter-spacing: 2px; 
}
.open-btn:hover { border-color: #ccc; color: #fff; }

/* オーバーレイ：背景黒 */
.overlay {
    display: none; 
    position: fixed; 
    top: 0; left: 0; 
    width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.9); 
    z-index: 1000; 
    justify-content: center; 
    align-items: center; 
    flex-direction: column;
}

/* ギャラリーコンテナ */
.gallery-content { 
    width: 90%; 
    max-width: 1000px; 
    text-align: center; 
    position: relative; 
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* メイン画像表示エリア */
.main-view { 
    width: 100%;
    height: 60vh; 
    margin-bottom: 40px; 
    display: flex; 
    justify-content: center; 
    align-items: center; 
}
.main-img { 
    max-width: 100%; 
    max-height: 100%; 
    object-fit: contain; 
}

/* サムネイルエリア（メイン画像の75%幅に制限） */
.thumb-nav-container { 
    display: flex; 
    align-items: center; 
    justify-content: center; 
    width: 75%; 
    margin: 0 auto;
}

/* 矢印：背景なし */
.arrow {
    color: #fff; 
    font-size: 32px; 
    cursor: pointer; 
    user-select: none;
    padding: 0 15px; 
    opacity: 0.5; 
    transition: 0.3s; 
    font-weight: 100;
}
.arrow:hover { opacity: 1; }

/* サムネイル表示窓 */
.thumb-viewport {
    overflow: hidden; 
    white-space: nowrap; 
    scroll-behavior: smooth;
    flex-grow: 1;
}

/* サムネイル単体 */
.thumb {
    width: 120px; 
    height: 80px; 
    object-fit: cover; 
    margin-right: 10px;
    cursor: pointer; 
    opacity: 0.6; 
    transition: 0.5s ease;
}
.thumb.active { opacity: 1; }

/* 極細×ボタン（通常時80%） */
.close-btn { 
    position: absolute; 
    top: -60px; 
    right: 0; 
    width: 30px; 
    height: 30px; 
    cursor: pointer; 
    opacity: 0.8; 
    transition: 0.3s;
}

.close-btn:hover { opacity: 1; }
.close-btn::before, .close-btn::after {
    content: ''; 
    position: absolute; 
    top: 50%; left: 0;
    width: 100%; 
    height: 1px; 
    background-color: #fff;
}
.close-btn::before { transform: rotate(45deg); }
.close-btn::after { transform: rotate(-45deg); }