:root {
    --primary-blue: #1e3c72;
    --secondary-blue: #2a5298;
    --accent-blue: #4a7dff;
    --light-blue: #f0f5ff;
    --lighter-blue: #f9fbff;
    --border-blue: #d0ddff;
    --text-dark: #333333;
    --text-medium: #555555;
    --text-light: #777777;
    --success-green: #28a745;
    --warning-orange: #ffc107;
    --error-red: #dc3545;
    --shadow-light: rgba(0, 0, 120, 0.08);
    --shadow-medium: rgba(0, 0, 120, 0.15);
    --star-color: #ffc107;
    --star-empty: #e0e0e0;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

body {
    background-color: #f8fafc;
    color: var(--text-dark);
    line-height: 1.6;
    min-height: 100vh;
}

.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    max-width: 1800px;
    margin: 0 auto;
    position: relative;
}

/* Header */
.main-header {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-blue) 100%);
    color: white;
    padding: 1.5rem 2rem;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 100%;
}

.logo-section {
    display: flex;
    align-items: center;
}

.logo-icon {
    font-size: 2.5rem;
    margin-right: 1rem;
    background: rgba(255, 255, 255, 0.1);
    padding: 0.8rem;
    border-radius: 12px;
}

.logo-text h1 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.3rem;
}

.logo-text p {
    font-size: 0.95rem;
    opacity: 0.9;
}

.header-badge {
    background: rgba(255, 255, 255, 0.15);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* File Upload Section */
.upload-section {
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 16px var(--shadow-light);
    overflow: hidden;
}

.section-header {
    background: var(--lighter-blue);
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border-blue);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.section-header h2 {
    color: var(--primary-blue);
    font-size: 1.4rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.section-header h2 i {
    color: var(--accent-blue);
}

.file-counter {
    background: var(--accent-blue);
    color: white;
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
}

.upload-container {
    padding: 3rem 2rem;
    text-align: center;
}

.upload-area {
    border: 3px dashed var(--accent-blue);
    border-radius: 12px;
    padding: 4rem 2rem;
    background: var(--lighter-blue);
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.upload-area:hover {
    background: #e8f1ff;
    border-color: var(--secondary-blue);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px var(--shadow-medium);
}

.upload-area.drag-over {
    background: #e1ebff;
    border-color: var(--primary-blue);
    border-style: solid;
}

.upload-icon {
    font-size: 4rem;
    color: var(--accent-blue);
    margin-bottom: 1.5rem;
}

.upload-text {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-blue);
    margin-bottom: 0.8rem;
}

.upload-subtext {
    color: var(--text-medium);
    margin-bottom: 1.5rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
}

.upload-button {
    background: var(--accent-blue);
    color: white;
    border: none;
    padding: 1rem 2.5rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
}

.upload-button:hover {
    background: var(--secondary-blue);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(74, 125, 255, 0.3);
}

#fileInput {
    display: none;
}

/* Summary Cards */
.summary-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
}

.summary-card {
    background: white;
    border-radius: 10px;
    padding: 1.8rem;
    box-shadow: 0 4px 12px var(--shadow-light);
    display: flex;
    align-items: center;
    gap: 1.2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #f0f0f0;
}

.summary-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px var(--shadow-medium);
}

.card-icon {
    width: 60px;
    height: 60px;
    background: var(--light-blue);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: var(--accent-blue);
}

.card-content {
    flex: 1;
}

.card-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-blue);
    line-height: 1;
    margin-bottom: 0.3rem;
}

.card-label {
    color: var(--text-light);
    font-size: 0.95rem;
    font-weight: 500;
}

/* Control Buttons */
.controls-section {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: center;
}

.btn {
    padding: 1rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    gap: 0.8rem;
    border: none;
}

.btn-primary {
    background: var(--accent-blue);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: var(--secondary-blue);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(74, 125, 255, 0.3);
}

.btn-secondary {
    background: white;
    color: var(--accent-blue);
    border: 2px solid var(--border-blue);
}

.btn-secondary:hover {
    background: var(--light-blue);
    border-color: var(--accent-blue);
}

.btn-success {
    background: var(--success-green);
    color: white;
}

.btn-success:hover:not(:disabled) {
    background: #218838;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(40, 167, 69, 0.3);
}

.btn-warning {
    background: var(--warning-orange);
    color: white;
}

.btn-warning:hover:not(:disabled) {
    background: #e0a800;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(255, 193, 7, 0.3);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
}

/* Progress Bar */
.progress-bar {
    height: 4px;
    background: var(--border-blue);
    border-radius: 2px;
    overflow: hidden;
    margin-top: 1rem;
    width: 100%;
    flex: 1;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-blue), var(--secondary-blue));
    width: 0%;
    transition: width 0.5s ease;
    border-radius: 2px;
}

/* Preview Section */
.preview-section {
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 16px var(--shadow-light);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    flex: 1;
    border: 1px solid #f0f0f0;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.2rem 1.5rem;
    background: var(--light-blue);
    border-bottom: 1px solid var(--border-blue);
}

.preview-header h3 {
    color: var(--primary-blue);
    font-size: 1.3rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.sheet-selector {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.sheet-selector label {
    color: var(--text-medium);
    font-weight: 600;
    font-size: 0.9rem;
}

.sheet-select {
    padding: 0.6rem 1rem;
    border-radius: 6px;
    border: 1px solid var(--border-blue);
    background: white;
    color: var(--text-dark);
    font-weight: 500;
    min-width: 250px;
    cursor: pointer;
}

.sheet-select:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px rgba(74, 125, 255, 0.1);
}

.preview-container {
    flex: 1;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.preview-info-bar {
    padding: 0.8rem 1.5rem;
    background: #f8f9fa;
    border-bottom: 1px solid #e9ecef;
    font-size: 0.9rem;
    color: var(--text-medium);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.table-wrapper {
    flex: 1;
    overflow: auto;
    position: relative;
    background: white;
}

.preview-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    min-width: 800px;
    font-size: 0.9rem;
}

.preview-table thead {
    position: sticky;
    top: 0;
    z-index: 10;
}

.preview-table th {
    background: linear-gradient(135deg, #1E3C72 0%, #2A5298 100%);
    color: white;
    font-weight: 600;
    padding: 0.8rem;
    text-align: left;
    position: sticky;
    top: 0;
    z-index: 10;
    border-bottom: 2px solid rgba(255, 255, 255, 0.2);
    border-right: 1px solid rgba(255, 255, 255, 0.2);
    min-width: 120px;
}

.preview-table th.source-column {
    background: linear-gradient(135deg, #0d2b5e 0%, #1a3c72 100%);
    border-right: 2px solid white;
    position: sticky;
    left: 0;
    z-index: 11;
}

.preview-table th:first-child {
    background: linear-gradient(135deg, #0d2b5e 0%, #1a3c72 100%);
    position: sticky;
    left: 0;
    z-index: 11;
}

.preview-table th:nth-child(2) {
    background: linear-gradient(135deg, #0d2b5e 0%, #1a3c72 100%);
    position: sticky;
    left: 150px;
    z-index: 11;
}

.preview-table th:after {
    content: '';
    position: absolute;
    right: 0;
    top: 10%;
    height: 80%;
    width: 1px;
    background: rgba(255, 255, 255, 0.2);
}

.preview-table th:last-child:after {
    display: none;
}

.preview-table td {
    padding: 0.7rem;
    border-bottom: 1px solid #f1f3f5;
    border-right: 1px solid #f1f3f5;
    background: white;
}

.preview-table td.source-column {
    background: #f0f5ff;
    font-weight: 600;
    color: #1E3C72;
    border-right: 2px solid #d0ddff;
    position: sticky;
    left: 0;
    z-index: 1;
}

.preview-table tr:nth-child(even) td {
    background: #f8f9fa;
}

.preview-table tr:nth-child(even) td.source-column {
    background: #e6eeff;
}

.preview-table tr:hover td {
    background: #f8fbff;
}

.preview-table td:first-child {
    background: #f0f5ff;
    font-weight: 600;
    color: #1E3C72;
    position: sticky;
    left: 0;
    z-index: 9;
    border-right: 2px solid #d0ddff;
}

.preview-table td:nth-child(2) {
    background: #f0f5ff;
    font-weight: 600;
    color: #1E3C72;
    position: sticky;
    left: 150px;
    z-index: 9;
    border-right: 2px solid #d0ddff;
}

.preview-table tr:hover td:first-child,
.preview-table tr:hover td:nth-child(2) {
    background: #e6eeff;
}

.zero-value {
    color: #adb5bd;
    font-style: italic;
}

/* Info Panel */
.info-panel {
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 16px var(--shadow-light);
    overflow: hidden;
    border: 1px solid #f0f0f0;
}

.info-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-blue);
    background: var(--lighter-blue);
}

.info-tab {
    padding: 1.2rem 1.5rem;
    background: none;
    border: none;
    font-weight: 600;
    color: var(--text-medium);
    cursor: pointer;
    transition: all 0.3s;
    position: relative;
    font-size: 0.95rem;
}

.info-tab.active {
    color: var(--accent-blue);
    background: white;
}

.info-tab.active:after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--accent-blue);
}

.info-tab:hover:not(.active) {
    background: rgba(74, 125, 255, 0.1);
    color: var(--primary-blue);
}

.tab-content {
    padding: 2rem;
}

.tab-pane {
    display: none;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

.info-list {
    list-style: none;
}

.info-list li {
    margin-bottom: 1rem;
    padding-left: 1.8rem;
    position: relative;
    color: var(--text-medium);
    line-height: 1.6;
}

.info-list li:before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-green);
    font-weight: bold;
}

.disclaimer-box {
    background: #fff9e6;
    border-left: 4px solid var(--warning-orange);
    padding: 1.5rem;
    border-radius: 0 8px 8px 0;
    margin-top: 1.5rem;
}

.disclaimer-box h4 {
    color: #856404;
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    font-size: 1rem;
}

.disclaimer-box p {
    color: #856404;
    font-size: 0.9rem;
    line-height: 1.5;
}

/* FAQ Container */
.faq-container {
    padding: 2rem;
}

.faq-item {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-blue);
}

.faq-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.faq-item h3 {
    color: var(--primary-blue);
    font-size: 1.1rem;
    margin-bottom: 0.8rem;
    display: flex;
    align-items: flex-start;
    gap: 0.8rem;
    line-height: 1.4;
}

.faq-item h3:before {
    content: 'Q.';
    background: var(--accent-blue);
    color: white;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    font-weight: bold;
    flex-shrink: 0;
}

.faq-item p {
    color: var(--text-medium);
    line-height: 1.6;
    margin-left: 2.5rem;
    padding-left: 0.5rem;
    border-left: 3px solid var(--light-blue);
}

.faq-item ul {
    color: var(--text-medium);
    line-height: 1.6;
    margin-left: 3rem;
    margin-top: 0.5rem;
}

.faq-item li {
    margin-bottom: 0.3rem;
    position: relative;
    padding-left: 1.2rem;
}

.faq-item li:before {
    content: '•';
    color: var(--accent-blue);
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    padding: 1rem;
    animation: fadeIn 0.3s ease;
}

.modal {
    background: white;
    border-radius: 12px;
    width: 100%;
    max-width: 700px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-blue) 100%);
    color: white;
    padding: 1.8rem;
    border-radius: 12px 12px 0 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.close-modal {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background 0.3s;
    font-size: 1.5rem;
}

.close-modal:hover {
    background: rgba(255, 255, 255, 0.3);
}

.modal-body {
    padding: 2rem;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 1.2rem;
    margin: 1.5rem 0;
}

.summary-item {
    background: var(--lighter-blue);
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    border: 1px solid var(--border-blue);
}

.summary-label {
    font-size: 0.9rem;
    color: var(--text-medium);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.summary-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-blue);
}

/* Footer */
.main-footer {
    background: var(--primary-blue);
    color: white;
    padding: 1.5rem 2rem;
    text-align: center;
    font-size: 0.9rem;
    margin-top: auto;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 100%;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-links a:hover {
    color: white;
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

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

/* Progress bar animations */
@keyframes pulse {
    0% { opacity: 1; }
    50% { opacity: 0.5; }
    100% { opacity: 1; }
}

.processing {
    animation: pulse 1.5s infinite;
}

/* Loading states */
.btn.loading {
    position: relative;
    color: transparent !important;
}

.btn.loading::after {
    content: '';
    position: absolute;
    left: 50%;
    top: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Performance indicators */
.perf-badge {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
}

/* Memory usage indicator */
.memory-indicator {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 0.8rem;
    z-index: 1000;
    display: none;
}

.memory-indicator.visible {
    display: block;
}

/* Statistics Display */
.stats-container {
    position: fixed;
    bottom: 100px;
    right: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    padding: 1.5rem;
    z-index: 100;
    border: 2px solid var(--accent-blue);
    min-width: 250px;
    animation: slideInRight 0.3s ease;
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.stats-header {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin-bottom: 1.5rem;
    color: var(--primary-blue);
    font-weight: 600;
    border-bottom: 2px solid var(--border-blue);
    padding-bottom: 0.8rem;
    font-size: 1rem;
}

.stat-item {
    margin-bottom: 1.2rem;
}

.stat-value {
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent-blue);
    text-align: center;
    line-height: 1;
}

.stat-label {
    text-align: center;
    color: var(--text-light);
    font-size: 0.9rem;
    margin-top: 0.3rem;
}

.stat-date {
    text-align: center;
    color: var(--text-medium);
    font-size: 0.85rem;
    font-style: italic;
    margin-top: 0.2rem;
}

/* Responsive */
@media (max-width: 1200px) {
    .main-content {
        padding: 1.5rem;
    }
    
    .header-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .stats-container {
        bottom: 80px;
        right: 10px;
        min-width: 220px;
    }
}

@media (max-width: 768px) {
    .main-header {
        padding: 1.2rem;
    }
    
    .logo-text h1 {
        font-size: 1.5rem;
    }
    
    .upload-area {
        padding: 3rem 1rem;
    }
    
    .upload-text {
        font-size: 1.2rem;
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .preview-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .sheet-selector {
        width: 100%;
    }
    
    .sheet-select {
        flex: 1;
        min-width: unset;
    }
    
    .summary-section {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .controls-section {
        justify-content: center;
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .stats-container {
        position: static;
        margin-top: 1rem;
        width: 100%;
    }
    
    .modal {
        margin: 1rem;
    }
    
    .faq-item h3 {
        font-size: 1rem;
    }
    
    .faq-item p {
        margin-left: 2rem;
    }
}

@media (max-width: 480px) {
    .summary-section {
        grid-template-columns: 1fr;
    }
    
    .info-tabs {
        flex-wrap: wrap;
    }
    
    .info-tab {
        flex: 1;
        min-width: 120px;
        text-align: center;
        padding: 1rem;
        font-size: 0.85rem;
    }
    
    .summary-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
        gap: 1rem;
    }
    
    .faq-item h3:before {
        width: 24px;
        height: 24px;
        font-size: 0.8rem;
    }
    
    .faq-item p {
        margin-left: 1.5rem;
    }
}