:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --success-color: #22c55e;
    --background-color: #f8fafc;
    --surface-color: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --border-radius: 0.75rem;
    --border-radius-sm: 0.375rem;
    --border-radius-lg: 1rem;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    background: var(--surface-color);
    padding: 1rem 2rem;
    box-shadow: var(--shadow-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo i {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-link:hover {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 4rem 2rem;
    text-align: center;
}

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

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 3rem;
    opacity: 0.9;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    flex-wrap: wrap;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.stat-label {
    opacity: 0.8;
    font-size: 0.875rem;
}

/* Upload Section */
.upload-section {
    padding: 4rem 2rem;
    flex: 1;
}

.upload-container {
    max-width: 600px;
    margin: 0 auto;
}

.section-title {
    font-size: 2rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 0.5rem;
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    background: var(--surface-color);
    margin-bottom: 1.5rem;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(37, 99, 235, 0.05);
}

.upload-content h4 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.upload-content p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.upload-icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.file-types {
    display: inline-block;
    background: var(--background-color);
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.file-info {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 1rem;
    box-shadow: var(--shadow-sm);
    margin-bottom: 1.5rem;
}

.file-details {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.file-details i {
    font-size: 1.5rem;
    color: var(--success-color);
}

.file-text {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.file-name {
    font-weight: 500;
    color: var(--text-primary);
}

.file-size {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.remove-file {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--border-radius-sm);
    transition: all 0.2s;
}

.remove-file:hover {
    background: var(--background-color);
    color: var(--danger-color);
}

.predict-btn {
    width: 100%;
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.predict-btn:hover:not(:disabled) {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.predict-btn:disabled {
    background: var(--text-secondary);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

/* Loading */
.loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.loading-content {
    text-align: center;
    padding: 2rem;
}

.loader {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

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

.loading-content h4 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.loading-content p {
    color: var(--text-secondary);
}

/* Results Section */
.results-section {
    padding: 4rem 2rem;
    background: var(--surface-color);
}

.results-container {
    max-width: 1200px;
    margin: 0 auto;
}

.summary-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.summary-card {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: transform 0.2s;
}

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

.card-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: white;
}

.card-icon.low-risk {
    background: var(--success-color);
}

.card-icon.medium-risk {
    background: var(--warning-color);
}

.card-icon.high-risk {
    background: #f97316;
}

.card-icon.very-high-risk {
    background: var(--danger-color);
}

.card-content {
    display: flex;
    flex-direction: column;
}

.card-number {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
}

.card-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.chart-container {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    margin-bottom: 3rem;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.table-container {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    margin-bottom: 2rem;
}

.table-container h4 {
    padding: 1.5rem;
    margin: 0;
    background: var(--background-color);
    border-bottom: 1px solid var(--border-color);
}

.table-wrapper {
    overflow-x: auto;
}

.results-table {
    width: 100%;
    border-collapse: collapse;
}

.results-table th {
    background: var(--background-color);
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
}

.results-table td {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.results-table tbody tr:hover {
    background: var(--background-color);
}

.risk-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: white;
}

.risk-badge.low { background: var(--success-color); }
.risk-badge.medium { background: var(--warning-color); }
.risk-badge.high { background: #f97316; }
.risk-badge.very-high { background: var(--danger-color); }

.export-options {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.export-btn,
.reset-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.export-btn:hover {
    background: #059669;
    transform: translateY(-1px);
}

.reset-btn {
    background: var(--text-secondary);
    color: white;
}

.reset-btn:hover {
    background: #475569;
    transform: translateY(-1px);
}

/* Features Section */
.features-section {
    padding: 4rem 2rem;
    background: var(--background-color);
}

.features-container {
    max-width: 1200px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: transform 0.2s;
}

.feature-card:hover {
    transform: translateY(-4px);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin: 0 auto 1.5rem;
}

.feature-card h4 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 2rem 1rem;
    margin-top: auto;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.footer-section h4 {
    margin-bottom: 1rem;
    font-size: 1.125rem;
}

.footer-section p {
    opacity: 0.8;
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer-section a:hover {
    text-decoration: underline;
}

.footer-bottom {
    border-top: 1px solid #374151;
    margin-top: 2rem;
    padding-top: 1rem;
    text-align: center;
    opacity: 0.6;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1001;
}

.modal-content {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h4 {
    margin: 0;
    color: var(--text-primary);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: var(--border-radius-sm);
    transition: all 0.2s;
}

.modal-close:hover {
    background: var(--background-color);
    color: var(--text-primary);
}

.modal-body {
    padding: 1.5rem;
}

.modal-body p {
    margin: 0;
    color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: 1rem;
        flex-direction: column;
        gap: 1rem;
    }

    .nav {
        gap: 1rem;
    }

    .hero {
        padding: 3rem 1rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-stats {
        gap: 1.5rem;
    }

    .upload-section,
    .results-section,
    .features-section {
        padding: 3rem 1rem;
    }

    .upload-area {
        padding: 2rem 1rem;
    }

    .summary-cards {
        grid-template-columns: 1fr;
    }

    .export-options {
        flex-direction: column;
        align-items: center;
    }

    .export-btn,
    .reset-btn {
        width: 100%;
        max-width: 300px;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-stats {
        flex-direction: column;
        gap: 1rem;
    }

    .logo h1 {
        font-size: 1.25rem;
    }

    .section-title {
        font-size: 1.5rem;
    }
}