:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --background: #ffffff;
    --surface: #f8fafc;
    --border: #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);
    --radius: 0.5rem;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--surface);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

header {
    background: var(--background);
    padding: 2rem 0;
    text-align: center;
    border-bottom: 1px solid var(--border);
    position: relative;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

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

.language-selector {
    position: absolute;
    top: 1rem;
    right: 1rem;
}

.language-selector select {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--background);
    color: var(--text-primary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s;
}

.language-selector select:hover {
    border-color: var(--primary-color);
}

.language-selector select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

main {
    padding: 3rem 0;
}

.converter-section {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 2rem;
    align-items: start;
    margin-bottom: 4rem;
}

@media (max-width: 768px) {
    .converter-section {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .divider {
        transform: rotate(90deg);
        margin: 0;
    }
}

.input-group {
    background: var(--background);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

.input-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

textarea {
    width: 100%;
    min-height: 150px;
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    transition: all 0.2s;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.braille-text {
    font-size: 1.5rem;
    line-height: 2;
    font-family: 'Noto Sans Symbols', 'DejaVu Sans', sans-serif;
}

.button-group {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.primary-btn, .secondary-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

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

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

.secondary-btn {
    background: var(--background);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.secondary-btn:hover {
    background: var(--surface);
    border-color: var(--secondary-color);
}

.divider {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--text-secondary);
    user-select: none;
}

.info-section {
    background: var(--background);
    border-radius: var(--radius);
    padding: 3rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

.info-section h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.info-section p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature {
    text-align: center;
    padding: 1.5rem;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: all 0.2s;
}

.feature:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.feature h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.feature p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0;
}

.reference-section {
    background: var(--background);
    border-radius: var(--radius);
    padding: 3rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}

.reference-section h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.braille-chart {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

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

.chart-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 1rem;
}

.chart-item {
    text-align: center;
    padding: 1rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: all 0.2s;
}

.chart-item:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow);
    border-color: var(--primary-color);
}

.chart-item .char {
    display: block;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.chart-item .braille {
    display: block;
    font-size: 1.5rem;
    color: var(--primary-color);
    font-family: 'Noto Sans Symbols', 'DejaVu Sans', sans-serif;
}

footer {
    background: var(--background);
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
}

@media (max-width: 640px) {
    h1 {
        font-size: 2rem;
    }
    
    .language-selector {
        position: static;
        margin-top: 1rem;
    }
    
    .input-group {
        padding: 1.5rem;
    }
    
    .info-section,
    .reference-section {
        padding: 2rem 1.5rem;
    }
    
    .chart-grid {
        grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
        gap: 0.5rem;
    }
    
    .chart-item {
        padding: 0.75rem;
    }
}