* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

header {
    text-align: center;
    color: white;
    margin-bottom: 30px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    background: white;
    padding: 10px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.tab-btn {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    cursor: pointer;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.3s;
    color: #666;
}

.tab-btn:hover {
    background: #f5f5f5;
}

.tab-btn.active {
    background: #667eea;
    color: white;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.card {
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.card h2 {
    margin-bottom: 10px;
    color: #333;
}

.price {
    font-size: 1.2rem;
    color: #667eea;
    font-weight: 600;
    margin-bottom: 20px;
}

.upload-area {
    border: 2px dashed #ddd;
    border-radius: 10px;
    padding: 40px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    margin-bottom: 20px;
}

.upload-area:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

.upload-area.dragover {
    border-color: #667eea;
    background: #f0f4ff;
}

.upload-content svg {
    color: #667eea;
    margin-bottom: 15px;
}

.upload-content p {
    margin: 5px 0;
    color: #666;
}

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

.file-list {
    margin-bottom: 20px;
}

.file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 8px;
    cursor: move;
    transition: all 0.2s;
    position: relative;
}

.file-item:hover {
    background: #e9ecef;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.file-item.dragging {
    opacity: 0.5;
    background: #e3f2fd;
}

.file-item.drag-over {
    border-top: 3px solid #667eea;
    padding-top: 9px;
}

.file-item .drag-handle {
    margin-right: 12px;
    color: #999;
    cursor: grab;
    font-size: 1.2rem;
    flex-shrink: 0;
    align-self: center;
}

.file-item .drag-handle:active {
    cursor: grabbing;
}

.file-item span {
    flex: 1;
    color: #333;
    display: flex;
    align-items: center;
    min-width: 0;
}

.file-item .file-order {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    min-width: 24px;
    max-width: 24px;
    flex-shrink: 0;
    flex-grow: 0;
    background: #667eea;
    color: white;
    border-radius: 50%;
    font-size: 0.85rem;
    font-weight: 600;
    margin-right: 10px;
    box-sizing: border-box;
    aspect-ratio: 1;
}

.file-item .file-name {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: #333;
}

.file-info {
    margin-bottom: 20px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
    color: #333;
}

.merge-preview {
    margin: 20px 0;
    padding: 20px;
    background: linear-gradient(135deg, #f8f9ff 0%, #f0f4ff 100%);
    border-radius: 10px;
    border: 2px solid #667eea;
}

.merge-preview h3 {
    margin: 0 0 15px 0;
    color: #667eea;
    font-size: 1.1rem;
}

.preview-pdfs {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.preview-pdf-item {
    display: flex;
    align-items: center;
    padding: 12px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.preview-pdf-item .pdf-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: #667eea;
    color: white;
    border-radius: 50%;
    font-weight: 600;
    margin-right: 12px;
    flex-shrink: 0;
}

.preview-pdf-item .pdf-info {
    flex: 1;
    min-width: 0;
}

.preview-pdf-item .pdf-name {
    font-weight: 500;
    color: #333;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preview-pdf-item .pdf-details {
    font-size: 0.85rem;
    color: #666;
    margin-top: 4px;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.preview-arrow {
    margin: 0 8px;
    color: #667eea;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.preview-summary {
    margin-top: 15px;
    padding: 12px;
    background: white;
    border-radius: 8px;
    text-align: center;
    font-weight: 600;
    color: #667eea;
}

.btn {
    width: 100%;
    padding: 15px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

body.modal-open {
    overflow: hidden;
    position: fixed;
    width: 100%;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
    overflow: hidden;
    padding: 20px;
    box-sizing: border-box;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    margin: 0;
    padding: 30px;
    border-radius: 12px;
    max-width: 500px;
    width: 100%;
    position: relative;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    max-height: calc(100vh - 40px);
    box-sizing: border-box;
    overflow-y: auto;
    overflow-x: hidden;
}

.payment-title {
    margin-bottom: 20px;
}

#submit-payment {
    margin-top: 20px;
}

.close {
    position: absolute;
    right: 20px;
    top: 20px;
    font-size: 28px;
    font-weight: bold;
    color: #aaa;
    cursor: pointer;
}

.close:hover {
    color: #333;
}

.loading-overlay {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(5px);
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

.loading-overlay.active {
    display: flex;
}

.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

.loading-spinner-small {
    border: 3px solid #f3f3f3;
    border-top: 3px solid #667eea;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

#payment-status {
    margin-top: 15px;
    padding: 10px;
    border-radius: 6px;
    text-align: center;
}

#payment-status.success {
    background: #d4edda;
    color: #155724;
}

#payment-status.error {
    background: #f8d7da;
    color: #721c24;
}

@media (max-width: 600px) {
    header h1 {
        font-size: 2rem;
    }
    
    .card {
        padding: 20px;
    }
    
    .tabs {
        flex-direction: column;
    }
    
    .file-item {
        padding: 10px;
    }
    
    .file-item .drag-handle {
        margin-right: 8px;
        font-size: 1rem;
    }
    
    .file-item .file-order {
        width: 20px;
        height: 20px;
        min-width: 20px;
        max-width: 20px;
        font-size: 0.75rem;
        margin-right: 8px;
    }
    
    .file-item .file-name {
        font-size: 0.9rem;
    }
}