/* Design Tokens */
:root {
    --color-primary: #0066cc;
    --color-primary-hover: #0052a3;
    --color-secondary: #6c757d;
    --color-success: #28a745;
    --color-danger: #dc3545;
    --color-warning: #ffc107;
    --color-info: #17a2b8;
    
    --color-bg-main: #f8f9fa;
    --color-bg-card: #ffffff;
    --color-border: #dee2e6;
    --color-text-primary: #212529;
    --color-text-secondary: #6c757d;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
    
    --border-radius: 0.375rem;
    --border-radius-lg: 0.5rem;
    --box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --box-shadow-lg: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
    
    --transition-speed: 0.3s;
    
    --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-base);
    background-color: var(--color-bg-main);
    color: var(--color-text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-xl);
}

/* Header */
header {
    text-align: center;
    margin-bottom: var(--spacing-xxl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--color-border);
}

header h1 {
    color: var(--color-primary);
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.subtitle {
    color: var(--color-text-secondary);
    font-size: 1.125rem;
}

/* Upload Section */
.upload-section {
    background: var(--color-bg-card);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--box-shadow);
}

.upload-area {
    border: 2px dashed var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xxl);
    text-align: center;
    transition: all var(--transition-speed);
    position: relative;
}

.upload-area:hover,
.upload-area.drag-over {
    border-color: var(--color-primary);
    background-color: rgba(0, 102, 204, 0.05);
}

.upload-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
    display: flex;
    justify-content: center;
    align-items: center;
}

.upload-area h2 {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-primary);
}

.upload-area p {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
}

#fileInput {
    display: none;
}

.file-info {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background-color: var(--color-bg-main);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--color-success);
}

.file-info p {
    margin: var(--spacing-xs) 0;
}

/* Buttons */
.btn-primary,
.btn-secondary {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-speed);
    display: inline-block;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--box-shadow-lg);
}

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

.btn-secondary {
    background-color: var(--color-secondary);
    color: white;
    margin-right: var(--spacing-sm);
}

.btn-secondary:hover {
    background-color: #5a6268;
}

.btn-primary:focus,
.btn-secondary:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Analysis Section */
.analysis-section {
    background: var(--color-bg-card);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--box-shadow);
}

.analysis-section h2 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--color-border);
}

.analysis-section h3 {
    color: var(--color-text-primary);
    margin: var(--spacing-lg) 0 var(--spacing-md);
}

/* Sheet Selector */
.sheet-selector {
    margin-bottom: var(--spacing-xl);
}

.sheet-selector label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.sheet-selector select,
#rowLimit {
    width: 100%;
    max-width: 400px;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    font-size: 1rem;
    background-color: white;
    cursor: pointer;
}

.sheet-selector select:focus,
#rowLimit:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

/* Statistics */
.statistics {
    margin-bottom: var(--spacing-xl);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.stat-card {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-hover) 100%);
    color: white;
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    text-align: center;
    box-shadow: var(--box-shadow);
    transition: transform var(--transition-speed);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--box-shadow-lg);
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.9;
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-value {
    font-size: 2rem;
    font-weight: bold;
}

/* Data Preview */
.data-preview {
    margin-bottom: var(--spacing-xl);
}

.table-container {
    overflow-x: auto;
    margin: var(--spacing-md) 0;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
}

#dataTable {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

#dataTable th,
#dataTable td {
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

#dataTable th {
    background-color: var(--color-primary);
    color: white;
    font-weight: 600;
    position: sticky;
    top: 0;
    z-index: 10;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.5px;
}

#dataTable tbody tr:hover {
    background-color: rgba(0, 102, 204, 0.05);
}

#dataTable tbody tr:last-child td {
    border-bottom: none;
}

.preview-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.preview-controls label {
    font-weight: 500;
}

/* Export Section */
.export-section {
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.export-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    margin-top: var(--spacing-md);
}

/* Error Message */
.error-message {
    background-color: #f8d7da;
    color: #721c24;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--color-danger);
    margin: var(--spacing-lg) 0;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.error-icon {
    font-size: 1.5rem;
}

/* Loading State */
.loading {
    text-align: center;
    padding: var(--spacing-xxl);
}

.loading::after {
    content: "⏳ Wird geladen...";
    font-size: 1.125rem;
    color: var(--color-text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .upload-area {
        padding: var(--spacing-lg);
    }
    
    .upload-icon {
        font-size: 3rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .export-buttons {
        flex-direction: column;
    }
    
    .btn-secondary {
        margin-right: 0;
        margin-bottom: var(--spacing-sm);
    }
    
    .preview-controls {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .preview-controls select {
        width: 100%;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus visible for keyboard navigation */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000000;
    }
    
    .upload-area {
        border-width: 3px;
    }
}

/* Analysis Tabs */
.analysis-tabs {
    display: flex;
    gap: 0.5rem;
    border-bottom: 2px solid var(--color-border);
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.tab-button {
    padding: 0.75rem 1.5rem;
    background: transparent;
    border: none;
    border-bottom: 3px solid transparent;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: all var(--transition-speed);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.tab-button svg {
    flex-shrink: 0;
}

.tab-button:hover {
    color: var(--color-primary);
    background: rgba(0, 102, 204, 0.05);
}

.tab-button.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
    font-weight: 600;
}

.tab-content {
    display: none;
}

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

/* Business Analysis Sections */
.analysis-section {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: white;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--box-shadow);
    scroll-margin-top: 20px;
}

.analysis-section h2 {
    color: var(--color-primary);
    margin-bottom: 1rem;
    font-size: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--color-border);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.analysis-section h2 svg {
    flex-shrink: 0;
}

.analysis-section h3 {
    color: var(--color-text-primary);
    margin: 1.5rem 0 1rem;
    font-size: 1.25rem;
}

/* Stats Grid for multiple columns */
.stats-grid-4 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
}

.stat-card .stat-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

/* Analysis Table */
.analysis-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
    background: white;
}

.analysis-table th,
.analysis-table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

.analysis-table th {
    background: var(--color-primary);
    color: white;
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.5px;
    position: sticky;
    top: 0;
    z-index: 10;
}

.analysis-table tbody tr:hover {
    background: rgba(0, 102, 204, 0.05);
}

.analysis-table tbody tr:last-child td {
    border-bottom: none;
}

/* Financial Cards */
.financial-card {
    transition: transform var(--transition-speed);
}

.financial-card:hover {
    transform: translateY(-2px);
}

.financial-card.revenue {
    border-left-color: #17a2b8;
}

.financial-card.cost {
    border-left-color: #ffc107;
}

.financial-card.profit {
    border-left-color: #28a745;
}

.financial-card.loss {
    border-left-color: #dc3545;
}

.financial-card.writeoff {
    border-left-color: #dc3545;
}

.financial-card.gain {
    border-left-color: #28a745;
}

.financial-card.positive {
    border-left-color: #28a745;
}

.financial-card.negative {
    border-left-color: #dc3545;
}

/* Colored stat cards */
.stat-card.positive {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
}

.stat-card.negative {
    background: linear-gradient(135deg, #dc3545 0%, #c82333 100%);
}

/* Article Search */
.search-box {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
}

/* Article Details Display */
#articleDetails {
    animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Article Details Display */
#articleDetails {
    margin-top: 1.5rem;
}

.article-detail-card {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--box-shadow);
    margin-bottom: 1rem;
}

.article-detail-header {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--color-border);
}

.article-detail-item {
    padding: 0.75rem;
    background: var(--color-bg-main);
    border-radius: var(--border-radius);
}

.article-detail-item .label {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    margin-bottom: 0.25rem;
}

.article-detail-item .value {
    font-size: 1.25rem;
    font-weight: bold;
    color: var(--color-text-primary);
}

/* Movement History */
.movement-history {
    margin-top: 1rem;
}

.movement-item {
    padding: 1rem;
    background: var(--color-bg-main);
    border-radius: var(--border-radius);
    margin-bottom: 0.5rem;
    border-left: 4px solid var(--color-primary);
}

.movement-item.negative {
    border-left-color: #dc3545;
}

.movement-item.positive {
    border-left-color: #28a745;
}

/* Responsive adjustments for business analysis */
@media (max-width: 768px) {
    .analysis-tabs {
        flex-direction: column;
    }
    
    .tab-button {
        width: 100%;
        text-align: left;
        border-left: 3px solid transparent;
        border-bottom: 1px solid var(--color-border);
    }
    
    .tab-button.active {
        border-left-color: var(--color-primary);
        border-bottom-color: var(--color-border);
    }
    
    .stats-grid-4 {
        grid-template-columns: 1fr;
    }
    
    .search-box {
        flex-direction: column;
        align-items: stretch;
    }
    
    .search-box input,
    .search-box button {
        width: 100%;
        margin: 0;
    }
}

/* Print styles */
@media print {
    .upload-section,
    .export-section,
    .analysis-tabs,
    .search-box,
    .btn-primary,
    .btn-secondary {
        display: none !important;
    }
    
    .analysis-section {
        page-break-inside: avoid;
        box-shadow: none;
        border: 1px solid #000;
    }
    
    .analysis-table th {
        background: #000 !important;
        color: #fff !important;
    }
}

/* DataTables Custom Styling - Clean Minimal Design */
.dataTables_wrapper {
    padding: 0;
}

.dataTables_wrapper .dataTables_length,
.dataTables_wrapper .dataTables_filter {
    margin-bottom: 1rem;
}

.dataTables_wrapper .dataTables_filter label {
    font-size: 0.875rem;
    color: #666;
}

.dataTables_wrapper .dataTables_filter input {
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    padding: 0.5rem 0.75rem;
    margin-left: 0.5rem;
    font-size: 0.875rem;
}

.dataTables_wrapper .dataTables_filter input:focus {
    outline: none;
    border-color: #667eea;
}

.dataTables_wrapper .dataTables_length label {
    font-size: 0.875rem;
    color: #666;
}

.dataTables_wrapper .dataTables_length select {
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    padding: 0.375rem 1.5rem 0.375rem 0.5rem;
    margin: 0 0.5rem;
    font-size: 0.875rem;
}

.dataTables_wrapper .dataTables_info {
    padding-top: 1rem;
    color: #666;
    font-size: 0.875rem;
}

.dataTables_wrapper .dataTables_paginate .paginate_button {
    padding: 0.375rem 0.75rem;
    margin: 0 2px;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    background: white;
    color: #666 !important;
    cursor: pointer;
    font-size: 0.875rem;
}

.dataTables_wrapper .dataTables_paginate .paginate_button:hover {
    background: #f5f5f5;
    border-color: #667eea;
    color: #667eea !important;
}

.dataTables_wrapper .dataTables_paginate .paginate_button.current {
    background: #667eea !important;
    color: white !important;
    border-color: #667eea;
}

.dataTables_wrapper .dataTables_paginate .paginate_button.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

table.dataTable {
    width: 100% !important;
    border-collapse: collapse;
}

table.dataTable thead th {
    background: #667eea;
    color: white;
    padding: 0.75rem 1rem !important;
    font-weight: 600;
    text-align: left;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    border: none !important;
}

table.dataTable tbody td {
    padding: 0.75rem 1rem !important;
    border-bottom: 1px solid #f0f0f0 !important;
    font-size: 0.875rem;
}

table.dataTable tbody tr:hover {
    background-color: #f8f9ff;
}

table.dataTable.no-footer {
    border-bottom: 1px solid #e0e0e0;
}