/* リセットとベーススタイル */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Noto Sans JP', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ヘッダー */
.header {
    text-align: center;
    margin-bottom: 40px;
    background: rgba(255, 255, 255, 0.95);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #4a5568;
    margin-bottom: 10px;
}

.header h1 i {
    color: #667eea;
    margin-right: 15px;
}

.header p {
    font-size: 1.1rem;
    color: #718096;
    font-weight: 300;
}

/* メインコンテンツ */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 30px;
}

/* 設定パネル */
.settings-panel {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(248, 250, 252, 0.95) 100%);
    padding: 35px;
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08), 0 0 0 1px rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    position: relative;
    overflow: hidden;
}

.settings-panel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    border-radius: 24px 24px 0 0;
}

.settings-panel h2 {
    font-size: 1.5rem;
    color: #4a5568;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.settings-panel h2 i {
    color: #667eea;
}

.setting-item {
    margin-bottom: 25px;
    position: relative;
}

.setting-item label {
    display: block;
    font-weight: 600;
    color: #2d3748;
    margin-bottom: 10px;
    font-size: 1rem;
    position: relative;
}

.setting-item label::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 30px;
    height: 2px;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    border-radius: 1px;
}

.setting-item input {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.setting-item input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1), 0 4px 12px rgba(0, 0, 0, 0.08);
    transform: translateY(-1px);
}

.setting-item small {
    display: block;
    color: #718096;
    font-size: 0.9rem;
    margin-top: 5px;
}

.setting-buttons {
    display: flex;
    gap: 15px;
    margin-top: 20px;
    justify-content: center;
}

.setting-buttons .btn {
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.setting-buttons .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.setting-info {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-top: 20px;
    padding: 12px 16px;
    background: linear-gradient(135deg, #e6fffa 0%, #f0fff4 100%);
    border: 1px solid #9ae6b4;
    border-radius: 8px;
    color: #22543d;
    font-size: 0.9rem;
    font-weight: 500;
}

.setting-info i {
    color: #38a169;
    font-size: 1rem;
}

/* アップロードエリア */
.upload-area {
    background: rgba(255, 255, 255, 0.95);
    border: 3px dashed #cbd5e0;
    border-radius: 20px;
    padding: 60px 30px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    backdrop-filter: blur(10px);
}

.upload-area:hover,
.upload-area.dragover {
    border-color: #667eea;
    background: rgba(102, 126, 234, 0.05);
    transform: translateY(-2px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

.upload-content i {
    font-size: 4rem;
    color: #667eea;
    margin-bottom: 20px;
    display: block;
}

.upload-content h3 {
    font-size: 1.5rem;
    color: #4a5568;
    margin-bottom: 15px;
    font-weight: 500;
}

.upload-content p {
    color: #718096;
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.file-select-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.file-select-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.3);
}

/* 選択済みファイル表示エリア */
.selected-files-panel {
    margin-top: 20px;
    background: #f8fafc;
    border: 2px dashed #e2e8f0;
    border-radius: 15px;
    padding: 20px;
    transition: all 0.3s ease;
}

.selected-files-panel:hover {
    border-color: #cbd5e0;
    background: #f1f5f9;
}

.selected-files-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 2px solid #e2e8f0;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.selected-files-header h4 {
    margin: 0;
    color: #4a5568;
    font-size: 16px;
    font-weight: 600;
}

.file-count {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(72, 187, 120, 0.3);
}

.selected-files-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-height: 200px;
    overflow-y: auto;
}

.selected-file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: white;
    padding: 12px 15px;
    border-radius: 10px;
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.selected-file-item:hover {
    border-color: #cbd5e0;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transform: translateY(-1px);
}

.file-info {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
}

.file-icon {
    color: #667eea;
    font-size: 18px;
}

.file-details {
    display: flex;
    flex-direction: column;
}

.file-name {
    font-weight: 600;
    color: #2d3748;
    font-size: 14px;
    margin-bottom: 2px;
}

.file-size {
    font-size: 12px;
    color: #718096;
}

.file-status {
    display: flex;
    align-items: center;
    gap: 5px;
    font-size: 12px;
    font-weight: 600;
}

.status-processed {
    color: #48bb78;
}

.status-pending {
    color: #ed8936;
}

.remove-file-btn {
    background: #fed7d7;
    color: #c53030;
    border: none;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 12px;
}

.remove-file-btn:hover {
    background: #feb2b2;
    transform: scale(1.1);
}

/* 巻数自動設定ボタン */
.auto-volume-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
    display: flex;
    align-items: center;
    gap: 6px;
}

.auto-volume-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.auto-volume-btn:active {
    transform: translateY(0);
}

/* 巻数設定エリア */
.volume-controls {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-left: 10px;
}

.volume-input {
    width: 60px;
    padding: 4px 8px;
    border: 1px solid #e2e8f0;
    border-radius: 6px;
    font-size: 12px;
    text-align: center;
    background: white;
    transition: all 0.3s ease;
}

.volume-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.volume-label {
    font-size: 11px;
    color: #718096;
    font-weight: 600;
    white-space: nowrap;
}

/* ファイルアイテムのレイアウト調整 */
.selected-file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: white;
    padding: 12px 15px;
    border-radius: 10px;
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.file-main-info {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
}

.file-controls {
    display: flex;
    align-items: center;
    gap: 10px;
}

.auto-detected {
    font-size: 12px;
    cursor: help;
    opacity: 0.7;
    transition: opacity 0.3s ease;
}

.auto-detected:hover {
    opacity: 1;
}

/* 処理アクションエリア */
.process-actions {
    margin-top: 20px;
    padding-top: 15px;
    border-top: 2px solid #e2e8f0;
    display: flex;
    justify-content: center;
}

.process-btn {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 25px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(72, 187, 120, 0.3);
    display: flex;
    align-items: center;
    gap: 10px;
}

.process-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(72, 187, 120, 0.4);
}

.process-btn:active {
    transform: translateY(0);
}

.process-btn:disabled {
    background: #a0aec0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* 折り畳みセクション */
.collapsible-section {
    margin-bottom: 20px;
    border: 1px solid #e2e8f0;
    border-radius: 10px;
    overflow: hidden;
    background: white;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.collapsible-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    background: #f8fafc;
    cursor: pointer;
    transition: all 0.3s ease;
    border-bottom: 1px solid #e2e8f0;
}

.collapsible-header:hover {
    background: #f1f5f9;
}

.collapsible-header h4 {
    margin: 0;
    font-size: 16px;
    font-weight: 600;
}

.collapse-icon {
    transition: transform 0.3s ease;
    color: #718096;
    font-size: 14px;
}

.collapsible-content {
    padding: 20px;
    background: white;
}

.collapsible-content .result-item {
    margin-bottom: 15px;
    padding: 15px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #f8fafc;
}

.collapsible-content .result-item:last-child {
    margin-bottom: 0;
}

/* 個別書籍アイテム */
.book-item {
    margin-bottom: 10px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: white;
    overflow: hidden;
}

.book-item:last-child {
    margin-bottom: 0;
}

.book-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 15px;
    background: #f8fafc;
    cursor: pointer;
    transition: all 0.3s ease;
    border-bottom: 1px solid #e2e8f0;
}

.book-header:hover {
    background: #f1f5f9;
}

.book-header h5 {
    margin: 0;
    font-size: 14px;
    font-weight: 600;
    color: #2d3748;
    display: flex;
    align-items: center;
    gap: 8px;
}

.book-header h5 i {
    color: #667eea;
}

.error-header {
    background: #fed7d7;
}

.error-header:hover {
    background: #feb2b2;
}

.error-header h5 {
    color: #c53030;
}

.error-header h5 i {
    color: #e53e3e;
}

.book-content {
    padding: 15px;
    background: white;
    border-top: 1px solid #e2e8f0;
}

.book-info {
    font-size: 13px;
    line-height: 1.5;
}

.book-info p {
    margin: 8px 0;
    color: #4a5568;
}

.book-info strong {
    color: #2d3748;
    font-weight: 600;
}

.error-info {
    font-size: 13px;
    color: #c53030;
}

.error-info p {
    margin: 0;
    padding: 10px;
    background: #fed7d7;
    border-radius: 6px;
    border-left: 4px solid #e53e3e;
}

.summary-info {
    font-size: 14px;
    line-height: 1.6;
}

.summary-info p {
    margin: 10px 0;
    color: #4a5568;
}

.summary-info strong {
    color: #2d3748;
    font-weight: 600;
}

/* プログレスパネル */
.progress-panel {
    background: rgba(255, 255, 255, 0.95);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.progress-panel h3 {
    font-size: 1.5rem;
    color: #4a5568;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 15px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 10px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    color: #718096;
    font-size: 1rem;
    text-align: center;
}

/* 結果パネル */
.results-panel {
    background: rgba(255, 255, 255, 0.95);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.results-panel h3 {
    font-size: 1.5rem;
    color: #48bb78;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.results-content {
    margin-bottom: 25px;
    padding: 20px;
    background: #f7fafc;
    border-radius: 10px;
    border-left: 4px solid #48bb78;
}

.download-btn {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    justify-content: center;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(72, 187, 120, 0.3);
}

/* アクションボタンコンテナ */
.action-buttons {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.action-buttons .download-btn {
    flex: 2;
}

/* 続行ボタン */
.continue-btn {
    background: linear-gradient(135deg, #4299e1 0%, #3182ce 100%);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    flex: 1;
}

.continue-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(66, 153, 225, 0.3);
    background: linear-gradient(135deg, #3182ce 0%, #2c5aa0 100%);
}

.continue-btn:active {
    transform: translateY(0);
    box-shadow: 0 5px 15px rgba(66, 153, 225, 0.2);
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .action-buttons {
        flex-direction: column;
        gap: 10px;
    }
    
    .action-buttons .download-btn,
    .action-buttons .continue-btn {
        flex: none;
        width: 100%;
    }
}

/* エラーパネル */
.error-panel {
    background: rgba(255, 255, 255, 0.95);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.error-panel h3 {
    font-size: 1.5rem;
    color: #e53e3e;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.error-content {
    padding: 20px;
    background: #fed7d7;
    border-radius: 10px;
    border-left: 4px solid #e53e3e;
    color: #742a2a;
}

/* フッター */
.footer {
    text-align: center;
    margin-top: 40px;
    padding: 20px;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .header p {
        font-size: 1rem;
    }
    
    .upload-area {
        padding: 40px 20px;
    }
    
    .upload-content i {
        font-size: 3rem;
    }
    
    .upload-content h3 {
        font-size: 1.3rem;
    }
    
    .settings-panel,
    .progress-panel,
    .results-panel,
    .error-panel {
        padding: 20px;
    }
}

/* 結果表示のスタイル */
.result-item {
    margin-bottom: 20px;
    padding: 20px;
    border-radius: 10px;
    border-left: 4px solid #e2e8f0;
}

.result-item.success {
    background: #f0fff4;
    border-left-color: #48bb78;
}

.result-item.error {
    background: #fed7d7;
    border-left-color: #e53e3e;
}

.result-item h5 {
    margin-bottom: 15px;
    color: #4a5568;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.result-item h5 i {
    color: #667eea;
}

.book-info p,
.error-info p {
    margin-bottom: 8px;
    color: #4a5568;
    font-size: 0.95rem;
}

.book-info strong,
.error-info strong {
    color: #2d3748;
    font-weight: 500;
}

/* 書籍情報セクションのスタイル */
.book-section {
    margin-bottom: 20px;
    padding: 15px;
    background: rgba(255, 255, 255, 0.7);
    border-radius: 8px;
    border: 1px solid #e2e8f0;
}

.book-section h6 {
    margin: 0 0 12px 0;
    color: #4a5568;
    font-size: 1rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    padding-bottom: 8px;
    border-bottom: 2px solid #e2e8f0;
}

.book-section h6 i {
    color: #667eea;
    font-size: 0.9rem;
}

.book-section p {
    margin: 6px 0;
    color: #4a5568;
    font-size: 0.9rem;
    line-height: 1.4;
}

.book-section p strong {
    color: #2d3748;
    font-weight: 600;
    min-width: 100px;
    display: inline-block;
}

.book-section a {
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
}

.book-section a:hover {
    color: #5a67d8;
    text-decoration: underline;
}

/* ボリュームIDのスタイル */
.book-section code {
    background: #f7fafc;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    padding: 2px 6px;
    font-family: 'Courier New', monospace;
    font-size: 0.85rem;
    color: #2d3748;
}

.book-section code:hover {
    background: #edf2f7;
    border-color: #cbd5e0;
}

/* コピーボタンのスタイル */
.copy-btn {
    background: none;
    border: none;
    color: #667eea;
    cursor: pointer;
    padding: 2px 4px;
    margin: 0 4px;
    border-radius: 3px;
    font-size: 0.8rem;
    transition: all 0.2s ease;
}

.copy-btn:hover {
    background: #f7fafc;
    color: #5a67d8;
}

.copy-btn:active {
    transform: scale(0.95);
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .book-section {
        padding: 12px;
        margin-bottom: 15px;
    }
    
    .book-section h6 {
        font-size: 0.9rem;
    }
    
    .book-section p {
        font-size: 0.85rem;
    }
    
    .book-section p strong {
        min-width: 80px;
    }
}

.summary {
    border: 1px solid #e2e8f0;
}

.summary p {
    margin: 0;
    color: #4a5568;
    font-size: 1rem;
}

/* アニメーション */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.progress-panel,
.results-panel,
.error-panel {
    animation: fadeIn 0.5s ease;
}

/* ローディングアニメーション */
.fa-spinner {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

/* プログレスバーの改善 */
.progress-bar {
    background: linear-gradient(90deg, #e2e8f0 0%, #cbd5e0 100%);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
    height: 12px;
}

.progress-fill {
    background: linear-gradient(90deg, #4299e1 0%, #3182ce 50%, #2c5aa0 100%);
    height: 100%;
    border-radius: 10px;
    transition: width 0.3s ease;
    box-shadow: 0 2px 4px rgba(66, 153, 225, 0.3);
    position: relative;
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent 0%, rgba(255, 255, 255, 0.3) 50%, transparent 100%);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

.progress-text {
    font-weight: 500;
    color: #4a5568;
    margin-top: 8px;
    text-align: center;
}

/* プログレスパネルと結果パネルが同時表示される場合の調整 */
.progress-panel {
    margin-bottom: 20px;
}

.results-panel {
    margin-top: 0;
}

/* ダウンロードプログレスパネルのスタイル */
.download-progress-panel {
    background: rgba(72, 187, 120, 0.1);
    border: 2px solid #48bb78;
    border-radius: 12px;
    padding: 20px;
    margin: 20px 0;
    animation: fadeIn 0.5s ease;
}

.download-progress-panel h3 {
    color: #2f855a;
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.download-progress-panel h3 i {
    color: #48bb78;
}

.download-progress-panel .progress-bar {
    background: linear-gradient(90deg, #e2e8f0 0%, #cbd5e0 100%);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
    height: 12px;
    margin-bottom: 10px;
}

.download-progress-panel .progress-fill {
    background: linear-gradient(90deg, #48bb78 0%, #38a169 50%, #2f855a 100%);
    height: 100%;
    border-radius: 10px;
    transition: width 0.3s ease;
    box-shadow: 0 2px 4px rgba(72, 187, 120, 0.3);
    position: relative;
}

.download-progress-panel .progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent 0%, rgba(255, 255, 255, 0.3) 50%, transparent 100%);
    animation: shimmer 2s infinite;
}

.download-progress-panel .progress-text {
    font-weight: 500;
    color: #4a5568;
    text-align: center;
    font-size: 0.9rem;
}

/* 上に戻るボタン */
.scroll-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    border: 3px solid rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    box-shadow: 0 6px 20px rgba(72, 187, 120, 0.4);
    transition: all 0.3s ease;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px) scale(0.8);
    z-index: 1000;
}

.scroll-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.scroll-to-top:hover {
    transform: translateY(-5px) scale(1.1);
    box-shadow: 0 10px 30px rgba(72, 187, 120, 0.6);
    background: linear-gradient(135deg, #38a169 0%, #2f855a 100%);
    border-color: rgba(255, 255, 255, 0.3);
}

.scroll-to-top:active {
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 6px 20px rgba(72, 187, 120, 0.4);
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .scroll-to-top {
        bottom: 20px;
        right: 20px;
        width: 55px;
        height: 55px;
        font-size: 18px;
    }
}