/* Modern, clean styling for Positional Roman Numeral System */

:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #64748b;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --border-color: #475569;
    --success: #10b981;
    --error: #ef4444;
    --accent: #8b5cf6;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    padding: 0;
    margin: 0;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
    transition: margin-left 0.3s;
}

header {
    text-align: center;
    margin-bottom: 3rem;
    padding: 2rem 0;
    border-bottom: 2px solid var(--border-color);
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

section {
    margin-bottom: 3rem;
}

h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    border-left: 4px solid var(--primary-color);
    padding-left: 1rem;
}

/* Converter Section */
.converter-section {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.converter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.converter-card {
    background: var(--surface-light);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.converter-card label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.converter-card input {
    width: 100%;
    padding: 0.75rem;
    background: var(--background);
    border: 2px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 1rem;
    transition: border-color 0.3s;
}

.converter-card input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.converter-card button {
    width: 100%;
    padding: 0.75rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s, transform 0.1s;
}

.converter-card button:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.converter-card button:active {
    transform: translateY(0);
}

.separator-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.separator-controls label:first-child {
    font-weight: 600;
    color: var(--text-secondary);
}

.radio-group {
    display: flex;
    gap: 1.5rem;
}

.radio-group label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    color: var(--text-primary);
}

.radio-group input[type="radio"] {
    width: auto;
    margin: 0;
    cursor: pointer;
}

/* Results Section */
.results-section {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

.result-card {
    background: var(--surface-light);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.result-card h3 {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.result-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
    word-break: break-word;
}

.explanation-card {
    grid-column: 1 / -1;
}

.explanation-text {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-primary);
}

.error-card {
    background: rgba(239, 68, 68, 0.1);
    border: 2px solid var(--error);
    padding: 1.5rem;
    border-radius: 8px;
    grid-column: 1 / -1;
}

.error-card h3 {
    color: var(--error);
    margin-bottom: 0.5rem;
}

/* Comparison Table */
.comparison-section {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--surface-light);
    border-radius: 8px;
    overflow: hidden;
}

thead {
    background: var(--primary-color);
}

th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
    color: white;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.5px;
}

td {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-primary);
}

td code {
    background: var(--background);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent);
}

.explanation-cell {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Examples Section */
.examples-section {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.examples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.example-card {
    background: var(--surface-light);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

.example-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.4);
}

.example-card h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.example-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.example-values {
    margin-bottom: 1rem;
}

.example-value {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.example-value code {
    background: var(--background);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent);
}

.example-explanation {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

/* Info Section */
.info-section {
    background: var(--surface);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

.info-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.info-card {
    background: var(--surface-light);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.info-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.info-card p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.8;
}

.info-card ul {
    color: var(--text-secondary);
    margin-left: 1.5rem;
    line-height: 1.8;
}

.info-card li {
    margin-bottom: 0.5rem;
}

.digit-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.digit-table th,
.digit-table td {
    padding: 0.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.digit-table th {
    background: var(--background);
    color: var(--text-primary);
    font-weight: 600;
}

.digit-table td {
    color: var(--text-secondary);
}

.example-box {
    background: var(--background);
    padding: 1rem;
    border-radius: 6px;
    margin-top: 1rem;
    border-left: 4px solid var(--accent);
}

.example-box strong {
    color: var(--text-primary);
    display: block;
    margin-bottom: 0.5rem;
}

.example-box ul {
    margin: 0.5rem 0;
    margin-left: 1.5rem;
}

.example-box code {
    background: var(--surface);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    color: var(--accent);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 0;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    margin-top: 3rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }

    h1 {
        font-size: 2rem;
    }

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

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

    .separator-controls {
        flex-direction: column;
        align-items: flex-start;
    }

    .radio-group {
        flex-direction: column;
        gap: 0.5rem;
    }

    table {
        font-size: 0.9rem;
    }

    th, td {
        padding: 0.75rem 0.5rem;
    }
}