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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --error-color: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    padding: 20px;
    margin: 0;
}

.container {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 20px;
}

@media (min-width: 1400px) {
    .container {
        max-width: 1400px;
        padding: 0 40px;
    }
}

header {
    text-align: center;
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Form Styles */
#analysisForm {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    box-shadow: var(--shadow-lg);
    margin-bottom: 30px;
}

.form-section {
    margin-bottom: 25px;
}

.form-section:last-child {
    margin-bottom: 0;
}

.form-section h3 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: var(--text-primary);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 8px;
}

label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.help-text {
    display: block;
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: normal;
    margin-top: 4px;
}

.required {
    color: var(--error-color);
    margin-left: 4px;
}

input[type="text"],
input[type="number"],
textarea,
select {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
}

select option:disabled {
    color: var(--text-secondary);
    font-style: italic;
}

input[type="text"]::placeholder,
input[type="number"]::placeholder,
textarea::placeholder {
    color: #94a3b8;
    opacity: 0.7;
}

input[type="text"]:focus,
input[type="number"]:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

textarea {
    resize: vertical;
    min-height: 120px;
}

.input-group {
    display: flex;
    gap: 10px;
}

.input-group select {
    flex: 0 0 120px;
}

.input-group input {
    flex: 1;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.form-group {
    margin-bottom: 15px;
}

.form-group:last-child {
    margin-bottom: 0;
}

/* Toggle Section */
.toggle-section {
    margin-bottom: 25px;
}

.toggle-btn {
    width: 100%;
    padding: 15px 20px;
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.2s;
}

.toggle-btn:hover {
    background: #f1f5f9;
    border-color: var(--primary-color);
}

.toggle-icon {
    transition: transform 0.3s;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.toggle-btn.active .toggle-icon {
    transform: rotate(180deg);
}

.advanced-options {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    margin-top: 15px;
}

.advanced-options.open {
    max-height: 5000px;
    transition: max-height 0.5s ease-in;
}

/* Submit Button */
.submit-btn {
    width: 100%;
    padding: 16px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.submit-btn:hover:not(:disabled) {
    background: var(--primary-hover);
}

.submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Loader */
.loader {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Results */
.results {
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    margin-top: 30px;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 30px;
    border-bottom: 2px solid var(--border-color);
}

.results-header h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

.close-btn {
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    transition: background 0.2s;
}

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

.results-content {
    padding: 30px;
    max-height: 70vh;
    overflow-y: auto;
}

.results-actions {
    display: flex;
    gap: 15px;
    padding: 20px 30px;
    border-top: 2px solid var(--border-color);
    background: var(--bg-color);
    border-radius: 0 0 12px 12px;
}

.action-btn {
    flex: 1;
    padding: 12px 24px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

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

.download-btn:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
}

.clear-btn {
    background: var(--card-bg);
    color: var(--text-primary);
}

.clear-btn:hover {
    background: var(--bg-color);
    border-color: var(--text-secondary);
}

.results-content h1,
.results-content h2,
.results-content h3 {
    margin-top: 24px;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.results-content h1:first-child,
.results-content h2:first-child,
.results-content h3:first-child {
    margin-top: 0;
}

.results-content p {
    margin-bottom: 12px;
    line-height: 1.8;
}

.results-content a {
    color: var(--primary-color);
    text-decoration: underline;
    transition: color 0.2s;
}

.results-content a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.results-content a:visited {
    color: #7c3aed;
}

.results-content ul,
.results-content ol {
    margin-left: 24px;
    margin-bottom: 12px;
}

.results-content li {
    margin-bottom: 8px;
}

.results-content code {
    background: var(--bg-color);
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}

.results-content pre {
    background: var(--bg-color);
    padding: 15px;
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: 12px;
}

.results-content blockquote {
    border-left: 4px solid var(--primary-color);
    padding-left: 16px;
    margin-left: 0;
    color: var(--text-secondary);
    font-style: italic;
}

.results-content table,
.results-content .comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    font-size: 0.95rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
    overflow: hidden;
}

.results-content table th,
.results-content table td,
.results-content .comparison-table th,
.results-content .comparison-table td {
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    text-align: left;
    vertical-align: top;
}

.results-content table th,
.results-content .comparison-table th {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.5px;
}

.results-content table tbody tr:nth-child(even),
.results-content .comparison-table tbody tr:nth-child(even) {
    background: var(--bg-color);
}

.results-content table tbody tr:hover,
.results-content .comparison-table tbody tr:hover {
    background: rgba(59, 130, 246, 0.1);
}

.results-content .citation {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.85em;
    vertical-align: super;
}

/* Error */
.error {
    background: #fef2f2;
    border: 2px solid var(--error-color);
    border-radius: 12px;
    margin-top: 30px;
}

.error-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    background: var(--error-color);
    color: white;
    border-radius: 10px 10px 0 0;
}

.error-header h3 {
    font-size: 1.2rem;
}

.error-content {
    padding: 20px;
    color: var(--text-primary);
}

/* Responsive */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .container {
        padding: 0 10px;
    }

    header h1 {
        font-size: 2rem;
    }

    #analysisForm {
        padding: 20px;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

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

    .input-group select {
        flex: 1;
    }
}