:root {
    /* Sophisticated Color Palette */
    --taupe: #463f3a;
    --grey-olive: #8a817c;
    --silver: #bcb8b1;
    --parchment: #f4f3ee;
    --powder-blush: #e0afa0;

    /* Semantic Colors */
    --primary: var(--taupe);
    --secondary: var(--powder-blush);
    --accent: var(--grey-olive);
    --background: var(--parchment);
    --surface: #ffffff;
    --border: var(--silver);

    /* Status Colors */
    --success: #6b8e65;
    --warning: #d4a373;
    --danger: #c17767;

    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(70, 63, 58, 0.08);
    --shadow-md: 0 4px 12px rgba(70, 63, 58, 0.12);
    --shadow-lg: 0 8px 24px rgba(70, 63, 58, 0.15);
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--background);
    min-height: 100vh;
    padding: 40px 20px;
    color: var(--primary);
    line-height: 1.6;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 50px;
    padding: 0 20px;
}

header h1 {
    font-size: 3.5em;
    font-weight: 700;
    color: var(--taupe);
    margin-bottom: 20px;
    letter-spacing: -1px;
}

.description {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.1em;
    line-height: 1.8;
    color: var(--accent);
    font-weight: 400;
}

/* Main Content */
.main-content {
    display: grid;
    gap: 30px;
}

/* Card Styling */
.card {
    background: var(--surface);
    border-radius: 16px;
    padding: 40px;
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(188, 184, 177, 0.2);
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: var(--shadow-lg);
}

.card h2 {
    color: var(--primary);
    margin-bottom: 30px;
    font-size: 1.8em;
    font-weight: 600;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--secondary);
}

.card h3 {
    color: var(--primary);
    margin: 25px 0 18px;
    font-size: 1.3em;
    font-weight: 600;
}

/* Form Elements */
.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: var(--primary);
    font-size: 0.95em;
}

.form-group input[type="text"],
.form-group input[type="password"],
.form-group textarea,
select {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 1em;
    font-family: inherit;
    background: var(--surface);
    color: var(--primary);
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus,
select:focus {
    outline: none;
    border-color: var(--secondary);
    box-shadow: 0 0 0 3px rgba(224, 175, 160, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

/* Buttons */
.button-group {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 20px;
}

.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    letter-spacing: 0.3px;
}

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

.btn-primary:hover:not(:disabled) {
    background: #352e2a;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--powder-blush);
    color: var(--surface);
}

.btn-secondary:hover:not(:disabled) {
    background: #d39985;
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--accent);
    border: 2px solid var(--border);
}

.btn-outline:hover:not(:disabled) {
    background: var(--background);
    border-color: var(--accent);
}

.btn-sm {
    padding: 10px 20px;
    font-size: 0.9em;
}

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

/* Loading State */
.loading {
    text-align: center;
    padding: 50px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--silver);
    border-top-color: var(--taupe);
    border-radius: 50%;
    margin: 0 auto 20px;
    animation: spin 1s linear infinite;
}

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

/* Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    margin-bottom: 35px;
}

.metric-card {
    background: linear-gradient(135deg, var(--parchment) 0%, #ffffff 100%);
    padding: 30px 25px;
    border-radius: 12px;
    text-align: center;
    border: 1px solid rgba(188, 184, 177, 0.3);
    transition: all 0.3s ease;
}

.metric-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.metric-card.highlight {
    background: linear-gradient(135deg, var(--powder-blush) 0%, #d39985 100%);
    color: var(--surface);
}

.metric-card.success {
    background: linear-gradient(135deg, #6b8e65 0%, #5a7a55 100%);
    color: var(--surface);
}

.metric-card.warning {
    background: linear-gradient(135deg, #d4a373 0%, #c49360 100%);
    color: var(--surface);
}

.metric-card.danger {
    background: linear-gradient(135deg, #c17767 0%, #b16655 100%);
    color: var(--surface);
}

.metric-value {
    font-size: 2.8em;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -1px;
}

.metric-label {
    font-size: 0.9em;
    opacity: 0.85;
    font-weight: 500;
}

/* Answer Section */
.answer-section {
    background: var(--background);
    padding: 30px;
    border-radius: 12px;
    margin: 25px 0;
    border-left: 4px solid var(--secondary);
}

.answer-content {
    line-height: 1.9;
    color: var(--primary);
    white-space: pre-wrap;
    font-size: 1.05em;
}

/* Hallucination Analysis */
.eigenscore-section {
    margin: 35px 0;
    padding: 30px;
    background: var(--background);
    border-radius: 12px;
    border-left: 4px solid var(--powder-blush);
}

.eigenscore-details {
    margin-top: 20px;
}

.consistency-bar {
    height: 12px;
    background: linear-gradient(to right,
        var(--danger) 0%,
        var(--warning) 50%,
        var(--success) 100%);
    border-radius: 6px;
    position: relative;
    margin: 25px 0;
    overflow: hidden;
}

.consistency-fill {
    height: 100%;
    background: rgba(255, 255, 255, 0.4);
    border-radius: 6px;
    transition: width 0.6s ease;
    position: relative;
    backdrop-filter: blur(4px);
}

.consistency-fill::after {
    content: '';
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 20px;
    background: var(--primary);
    border-radius: 2px;
}

.eigenscore-info {
    margin-top: 20px;
}

.eigenscore-info p {
    margin: 12px 0;
    color: var(--accent);
    font-size: 1.05em;
}

.eigenscore-info strong {
    color: var(--primary);
}

/* Performance Metrics */
.performance-section {
    margin: 35px 0;
    padding: 30px;
    background: var(--background);
    border-radius: 12px;
}

.metrics-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0 8px;
    margin: 20px 0;
}

.metrics-table tr {
    background: var(--surface);
    border-radius: 8px;
}

.metrics-table td {
    padding: 16px;
}

.metrics-table td:first-child {
    color: var(--accent);
    font-weight: 500;
    border-radius: 8px 0 0 8px;
}

.metrics-table td:last-child {
    text-align: right;
    font-weight: 600;
    color: var(--primary);
    border-radius: 0 8px 8px 0;
}

/* Alternative Responses */
.alternatives-section {
    margin-top: 35px;
    padding: 30px;
    background: var(--background);
    border-radius: 12px;
}

#alternatives-content {
    margin-top: 20px;
}

.alternative-item {
    background: var(--surface);
    padding: 20px;
    margin: 15px 0;
    border-left: 4px solid var(--powder-blush);
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
}

/* Analytics Grid */
.analytics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
    margin-bottom: 25px;
}

/* Upload Section */
.upload-section {
    margin: 25px 0;
}

.upload-box {
    border: 3px dashed var(--border);
    border-radius: 16px;
    padding: 50px 40px;
    text-align: center;
    background: var(--background);
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-box:hover {
    border-color: var(--powder-blush);
    background: var(--surface);
    transform: translateY(-2px);
}

.upload-box.dragover {
    border-color: var(--success);
    background: rgba(107, 142, 101, 0.05);
}

.upload-icon {
    font-size: 4em;
    margin-bottom: 20px;
    opacity: 0.7;
}

.upload-text {
    color: var(--accent);
    margin-bottom: 25px;
    font-size: 1.05em;
}

#file-info {
    background: var(--background);
    padding: 20px;
    border-radius: 12px;
    margin-top: 20px;
    border-left: 4px solid var(--success);
}

#file-info p {
    margin: 8px 0;
    color: var(--accent);
}

#file-info strong {
    color: var(--primary);
}

/* Divider */
.divider {
    display: flex;
    align-items: center;
    text-align: center;
    margin: 35px 0;
}

.divider::before,
.divider::after {
    content: '';
    flex: 1;
    border-bottom: 2px solid var(--border);
}

.divider span {
    padding: 0 20px;
    color: var(--accent);
    font-weight: 600;
    font-size: 0.9em;
    letter-spacing: 1px;
}

/* Help Text */
.help-text {
    font-size: 0.9em;
    color: var(--accent);
    margin-top: 12px;
    line-height: 1.6;
}

.help-text a {
    color: var(--powder-blush);
    text-decoration: none;
    font-weight: 500;
}

.help-text a:hover {
    text-decoration: underline;
}

/* API Status */
#api-status {
    margin-left: 12px;
    font-weight: 600;
    font-size: 0.95em;
}

#api-status.success {
    color: var(--success);
}

#api-status.error {
    color: var(--danger);
}

/* Responsive Design */
@media (max-width: 1024px) {
    .container {
        max-width: 100%;
    }

    .card {
        padding: 30px;
    }
}

@media (max-width: 768px) {
    body {
        padding: 20px 15px;
    }

    header h1 {
        font-size: 2.5em;
    }

    .description {
        font-size: 1em;
    }

    .card {
        padding: 25px 20px;
    }

    .metrics-grid {
        grid-template-columns: 1fr;
    }

    .button-group {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .upload-box {
        padding: 35px 25px;
    }

    .upload-icon {
        font-size: 3em;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 2em;
    }

    .metric-value {
        font-size: 2.2em;
    }
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mt-20 {
    margin-top: 20px;
}

.mb-20 {
    margin-bottom: 20px;
}

/* Smooth Transitions */
* {
    transition-property: background-color, border-color, color, fill, stroke, opacity, box-shadow, transform;
    transition-duration: 0.3s;
    transition-timing-function: ease;
}

/* Focus Visible for Accessibility */
*:focus-visible {
    outline: 2px solid var(--powder-blush);
    outline-offset: 2px;
}