.pdf-merge-section {
    padding: 40px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.pdf-merge-section .container {
    max-width: 1000px;
}

.calculator-header {
    text-align: center;
    margin-bottom: 30px;
}

.calculator-title {
    font-size: 2.5rem;
    color: #fff;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.calculator-title i {
    margin-right: 15px;
    font-size: 2.2rem;
}

.calculator-subtitle {
    font-size: 1.1rem;
    color: rgba(255,255,255,0.9);
    margin-bottom: 20px;
}

.calculator-badge {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
}

.badge-item {
    background: rgba(255,255,255,0.2);
    color: #fff;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    backdrop-filter: blur(10px);
}

.merge-main {
    background: #fff;
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.15);
}

.upload-section {
    margin-bottom: 25px;
}

.upload-box {
    border: 2px dashed #d0d7de;
    border-radius: 12px;
    padding: 50px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #fafbfc;
}

.upload-box:hover {
    border-color: #667eea;
    background: #f0f4ff;
}

.upload-box.dragover {
    border-color: #667eea;
    background: #e8f0ff;
    transform: scale(1.02);
}

.upload-box i {
    font-size: 3rem;
    color: #667eea;
    margin-bottom: 15px;
}

.upload-text {
    font-size: 1.1rem;
    color: #333;
    margin-bottom: 5px;
}

.upload-hint {
    font-size: 0.9rem;
    color: #999;
}

.file-list-section {
    margin-bottom: 25px;
}

.list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 2px solid #e8e8e8;
}

.list-title {
    font-size: 1.2rem;
    color: #333;
    display: flex;
    align-items: center;
}

.list-title i {
    margin-right: 10px;
    color: #667eea;
}

.list-actions {
    display: flex;
    gap: 8px;
}

.move-btn, .remove-all-btn {
    width: 36px;
    height: 36px;
    border-radius: 6px;
    border: 1px solid #e8e8e8;
    background: #fff;
    color: #666;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.move-btn:hover, .remove-all-btn:hover {
    border-color: #667eea;
    color: #667eea;
}

.remove-all-btn {
    border-color: #ff4757;
    color: #ff4757;
}

.remove-all-btn:hover {
    background: #ff4757;
    color: #fff;
}

.file-list {
    max-height: 400px;
    overflow-y: auto;
    margin-bottom: 20px;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.file-item:hover {
    background: #f0f4ff;
}

.file-item.selected {
    border-color: #667eea;
    background: #e8f0ff;
}

.file-item.dragging {
    opacity: 0.5;
}

.file-item.drag-over {
    border-color: #667eea;
    background: #e8f0ff;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 15px;
    flex: 1;
}

.file-icon {
    font-size: 2rem;
    color: #dc3545;
}

.file-meta {
    flex: 1;
}

.file-name {
    font-weight: 600;
    color: #333;
    margin-bottom: 5px;
}

.file-size {
    font-size: 0.85rem;
    color: #999;
}

.remove-file-btn {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: none;
    background: #ff4757;
    color: #fff;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.remove-file-btn:hover {
    background: #ff3838;
    transform: scale(1.1);
}

.merge-actions {
    display: flex;
    gap: 15px;
    margin-bottom: 25px;
}

.merge-btn, .preview-btn {
    flex: 1;
    padding: 14px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.merge-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.merge-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.6);
}

.preview-btn {
    background: #fff;
    color: #666;
    border: 2px solid #e8e8e8;
}

.preview-btn:hover {
    border-color: #667eea;
    color: #667eea;
}

.progress-section {
    margin-bottom: 25px;
    padding: 30px;
    background: #f8f9fa;
    border-radius: 12px;
}

.progress-header {
    text-align: center;
    margin-bottom: 20px;
}

.progress-title {
    font-size: 1.2rem;
    color: #667eea;
    display: flex;
    align-items: center;
    justify-content: center;
}

.progress-title i {
    margin-right: 10px;
}

.progress-bar-container {
    width: 100%;
    height: 30px;
    background: #e8e8e8;
    border-radius: 15px;
    overflow: hidden;
    position: relative;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #fff;
    font-weight: 600;
    font-size: 0.9rem;
}

.result-section {
    padding: 30px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    color: #fff;
}

.result-header {
    text-align: center;
    margin-bottom: 20px;
}

.result-title {
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.result-title i {
    margin-right: 10px;
}

.result-stats {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 25px;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.1rem;
}

.stat-item i {
    font-size: 1.3rem;
}

.download-actions {
    display: flex;
    gap: 15px;
}

.download-btn, .new-merge-btn {
    flex: 1;
    padding: 14px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.download-btn {
    background: #fff;
    color: #667eea;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}

.new-merge-btn {
    background: rgba(255,255,255,0.2);
    color: #fff;
    border: 2px solid rgba(255,255,255,0.3);
}

.new-merge-btn:hover {
    background: rgba(255,255,255,0.3);
}

.calculator-guide {
    margin-top: 30px;
    padding: 30px;
    background: rgba(255,255,255,0.1);
    border-radius: 16px;
    backdrop-filter: blur(10px);
}

.guide-title {
    font-size: 1.3rem;
    color: #fff;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
}

.guide-title i {
    margin-right: 10px;
}

.guide-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.guide-item {
    text-align: center;
    padding: 20px;
    background: rgba(255,255,255,0.1);
    border-radius: 12px;
}

.guide-icon {
    width: 50px;
    height: 50px;
    margin: 0 auto 10px;
    background: rgba(255,255,255,0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.3rem;
}

.guide-item h3 {
    color: #fff;
    font-size: 1rem;
    margin-bottom: 5px;
}

.guide-item p {
    color: rgba(255,255,255,0.8);
    font-size: 0.85rem;
    margin: 0;
}

.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: rgba(0,0,0,0.8);
    color: #fff;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 0.9rem;
    z-index: 10000;
    opacity: 0;
    transition: all 0.3s ease;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

@media (max-width: 768px) {
    .calculator-title {
        font-size: 1.8rem;
    }
    
    .result-stats {
        flex-direction: column;
        gap: 15px;
    }
    
    .download-actions {
        flex-direction: column;
    }
    
    .merge-actions {
        flex-direction: column;
    }
}