* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    --monospace: 'SF Mono', 'Monaco', 'Consolas', 'Liberation Mono', 'Courier New', monospace;
}

body {
    font-family: sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f5f5f5;
}

.header {
    background: #2c3e50;
    color: white;
    padding: 1rem;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.header h1 {
    margin-bottom: 0.5rem;
    font-size: 2rem;
}

.header p {
    opacity: 0.9;
    font-size: 1rem;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    min-height: calc(100vh - 120px);
}

.panel {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

.panel-header {
    background: #34495e;
    color: white;
    padding: 0.75rem 1rem;
    font-weight: bold;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.panel-content {
    flex: 1;
    padding: 1rem;
    display: flex;
    flex-direction: column;
}

.input-group {
    margin-bottom: 1rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #2c3e50;
    font-size: 0.9rem;
}

textarea, input[type="text"] {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #ddd;
    border-radius: 4px;
    font-family: var(--monospace);
    font-size: 0.9rem;
    line-height: 1.4;
    resize: vertical;
    transition: border-color 0.2s;
}

textarea:focus, input[type="text"]:focus {
    outline: none;
    border-color: #3498db;
}

#regex-input {
    height: 80px;
    font-weight: bold;
}

#text-input {
    height: 120px;
}

.flags-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.flag-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.flag-group input[type="checkbox"] {
    width: auto;
}

.flag-group label {
    margin: 0;
    font-weight: normal;
    font-size: 0.85rem;
    cursor: pointer;
}

.output-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.output-section {
    border: 1px solid #ddd;
    border-radius: 4px;
    overflow: hidden;
}

.output-header {
    background: #ecf0f1;
    padding: 0.5rem 0.75rem;
    font-weight: bold;
    font-size: 0.85rem;
    color: #2c3e50;
    border-bottom: 1px solid #ddd;
}

.output-content {
    padding: 0.75rem;
    background: #fafafa;
    min-height: 60px;
    max-height: 200px;
    overflow-y: auto;
    font-size: 0.85rem;
    line-height: 1.4;
    font-family: var(--monospace);
}

.match-highlight {
    background: #e74c3c;
    color: white;
    padding: 1px 2px;
    border-radius: 2px;
    font-weight: bold;
}

.capture-highlight {
    background: #9b59b6;
    color: white;
    padding: 1px 2px;
    border-radius: 2px;
    font-weight: bold;
}

.error {
    color: #e74c3c;
    background: #fdf2f2;
    padding: 0.75rem;
    border-radius: 4px;
    border: 1px solid #fecaca;
    font-size: 0.85rem;
}

.success {
    color: #27ae60;
    font-weight: bold;
}

.info {
    color: #7f8c8d;
    font-style: italic;
}

.toggle-section {
    margin-bottom: 1rem;
}

.toggle-btn {
    background: #3498db;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: background-color 0.2s;
}

.toggle-btn:hover {
    background: #2980b9;
}

.toggle-btn.active {
    background: #27ae60;
}

.hidden {
    display: none;
}

.parse-tree {
    background: #2c3e50;
    color: #ecf0f1;
    padding: 1rem;
    border-radius: 4px;
    white-space: pre-wrap;
    font-family: var(--monospace);
    font-size: 0.8rem;
    line-height: 1.3;
    overflow-y: auto;
}

.loading {
    opacity: 0.6;
    pointer-events: none;
}

@media (max-width: 768px) {
    .container {
        grid-template-columns: 1fr;
    }
    
    .flags-container {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    }
}

footer {
    text-align: center;
    padding: 1rem;
    background-color: #2c3e50;
    color: #ecf0f1;
    font-size: 0.9rem;
    margin-top: 2rem;
}

footer a {
    color: #ecf0f1;
    text-decoration: none;
}

#highlighted-text {
    white-space: pre-line;
}