/* --- 1. 基本設定 --- */
:root { --item-height: 70vh; --gap: 2vmin; }
*, *::before, *::after { box-sizing: border-box; }
body { background-color: #121212; color: #ffffff; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; margin: 0; overflow: hidden; }

/* --- 2. ヘッダー --- */
.site-header {
    position: fixed; top: 0; left: 0; width: 100%; z-index: 100;
    display: flex; flex-direction: column; align-items: center;
    padding: 1.5rem 2rem;
    background-color: rgba(18, 18, 18, 0.9);
    backdrop-filter: blur(12px); box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    transform: translateY(-120%); opacity: 0; visibility: hidden;
    transition: transform 0.5s cubic-bezier(0.65, 0, 0.35, 1), opacity 0.5s, visibility 0.5s;
}
.site-header.active { transform: translateY(0); opacity: 1; visibility: visible; }
/* ★★★ 変更点：ナビゲーションのスタイルを削除 ★★★ */
.upload-container { display: flex; justify-content: center; gap: 2rem; width: 100%; max-width: 1200px; margin: 0 auto; }
.upload-zone { flex: 1; padding: 1.5rem; border: 1px solid rgba(255, 255, 255, 0.1); border-radius: 12px; background-color: rgba(255, 255, 255, 0.03); text-align: center; transition: background-color 0.3s; }
.upload-zone:hover { background-color: rgba(255, 255, 255, 0.07); }
.upload-zone h3 { margin: 0 0 0.5rem 0; font-size: 1rem; color: #fff; }
.upload-zone p { margin: 0 0 1rem 0; font-size: 0.8rem; color: #aaa; min-height: 2.4em; }
.upload-form { display: flex; flex-direction: column; align-items: center; gap: 0.8rem; }
.upload-form button { width: 100%; padding: 0.6rem; font-size: 0.9rem; border: 1px solid rgba(255,255,255,0.5); background-color: rgba(0,0,0,0.3); color: white; border-radius: 6px; cursor: pointer; transition: background-color 0.2s; }
.upload-form button:hover { background-color: rgba(255,255,255,0.2); }
.upload-form button:disabled { background-color: #555; cursor: not-allowed; }

/* --- 3. スライダー --- */
.slider-wrapper { position: relative; width: 100%; height: 100vh; }
.slider {
    position: absolute; top: 0; left: 0;
    width: 100%; height: 100vh; display: flex; align-items: center; overflow: hidden;
    opacity: 0; visibility: hidden; transition: opacity 0.6s ease, visibility 0.6s;
}
.slider.active { opacity: 1; visibility: visible; }
.slider-track { display: flex; gap: var(--gap); will-change: transform; }

/* --- 4. ギャラリーアイテム --- */
.gallery-item { width: auto; height: var(--item-height); flex-shrink: 0; position: relative; border-radius: 12px; overflow: hidden; background-color: #1a1a1a; box-shadow: 0 10px 30px rgba(0,0,0,0.5); display: flex; align-items: center; }
.gallery-item img, .gallery-item video { height: 100%; width: auto; transition: transform 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94); }
.gallery-item:hover img, .gallery-item:hover video { transform: scale(1.02); }

/* --- 5. オーバーレイ --- */
.item-overlay { position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: linear-gradient(to top, rgba(0,0,0,0.8), transparent 50%); display: flex; justify-content: center; align-items: flex-end; gap: 1rem; padding-bottom: 1.5rem; opacity: 0; transition: opacity 0.3s ease; pointer-events: none; }
.gallery-item:hover .item-overlay { opacity: 1; pointer-events: auto; }
.control-btn { padding: 0.6rem 1.2rem; font-size: 0.9rem; font-weight: 500; text-decoration: none; border: 1px solid rgba(255,255,255,0.7); background-color: rgba(20,20,20,0.5); backdrop-filter: blur(10px); color: white; border-radius: 50px; cursor: pointer; transition: all 0.2s; }
.control-btn:hover { background-color: rgba(255,255,255,0.9); color: #121212; border-color: transparent; }
.delete-btn { font-family: inherit; }

/* --- 6. レスポンシブ対応 --- */
@media (max-width: 992px) { .upload-container { flex-direction: column; } }
@media (orientation: portrait) { :root { --item-height: 80vh; } .gallery-item { max-width: 90vw; } }

/* --- 7. UIボタン --- */
#upload-toggle-button { position: fixed; bottom: 2rem; right: 2rem; width: 60px; height: 60px; background-color: rgba(255, 255, 255, 0.9); color: #121212; border-radius: 50%; box-shadow: 0 5px 15px rgba(0,0,0,0.3); cursor: pointer; z-index: 101; transition: transform 0.3s ease, background-color 0.3s ease; }
#upload-toggle-button:hover { transform: scale(1.1); }
.icon-bar { position: absolute; top: 50%; left: 50%; width: 28px; height: 2px; background-color: #121212; transition: transform 0.3s cubic-bezier(0.65, 0, 0.35, 1); }
.icon-bar:first-child { transform: translate(-50%, -50%); }
.icon-bar:last-child { transform: translate(-50%, -50%) rotate(90deg); }
#upload-toggle-button.active .icon-bar:first-child { transform: translate(-50%, -50%) rotate(45deg); }
#upload-toggle-button.active .icon-bar:last-child { transform: translate(-50%, -50%) rotate(-45deg); }

/* ★★★ 追加：セクション切り替えボタン ★★★ */
#section-toggle-button {
    position: fixed;
    bottom: 2rem;
    left: 2rem;
    width: 60px;
    height: 60px;
    background-color: rgba(255, 255, 255, 0.9);
    color: #121212;
    border-radius: 50%;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
    cursor: pointer;
    z-index: 101;
    display: grid;
    place-items: center;
    font-size: 1.2rem;
    font-weight: 600;
    transition: transform 0.3s ease;
}
#section-toggle-button:hover {
    transform: scale(1.1);
}