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

:root {
    --primary-color: #3178c6;
    --primary-hover: #2563a8;
    --secondary-color: #6b7280;
    --background-color: #0f172a;
    --surface-color: #1e293b;
    --surface-hover: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --error-color: #ef4444;
    --success-color: #22c55e;
    --font-mono: 'SF Mono', 'Fira Code', 'Monaco', 'Consolas', monospace;
}

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

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

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

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

main {
    flex: 1;
}

.editor-container {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.editor-panel {
    background-color: var(--surface-color);
    border-radius: 12px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    min-height: 400px;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.panel-header h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.panel-actions {
    display: flex;
    gap: 0.5rem;
}

textarea {
    flex: 1;
    width: 100%;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1rem;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.5;
    resize: none;
    transition: border-color 0.2s;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

textarea::placeholder {
    color: var(--text-secondary);
}

.controls {
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn {
    padding: 0.625rem 1.25rem;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

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

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

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

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

.error-message {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
    min-height: 1.25rem;
}

.success-message {
    color: var(--success-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
    min-height: 1.25rem;
}

.options-panel {
    background-color: var(--surface-color);
    border-radius: 12px;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
}

.options-panel h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.option {
    display: flex;
    flex-direction: column;
    gap: 0.375rem;
}

.option span {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.option input[type="text"] {
    padding: 0.5rem 0.75rem;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 0.875rem;
    transition: border-color 0.2s;
}

.option input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.checkbox-option {
    flex-direction: row;
    align-items: center;
    cursor: pointer;
}

.checkbox-option input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

.examples-panel {
    background-color: var(--surface-color);
    border-radius: 12px;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
}

.examples-panel h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.examples-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.example-btn {
    padding: 0.5rem 1rem;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s;
}

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

footer {
    text-align: center;
    padding: 2rem 0 1rem;
    margin-top: auto;
}

footer a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.2s;
}

footer a:hover {
    color: var(--primary-color);
}

/* Mobile responsive styles */
@media (max-width: 900px) {
    .editor-container {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto;
    }

    .controls {
        padding: 0.5rem 0;
    }

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

    .editor-panel {
        min-height: 300px;
    }

    header h1 {
        font-size: 2rem;
    }
}

@media (max-width: 600px) {
    .container {
        padding: 1rem 0.75rem;
    }

    header h1 {
        font-size: 1.75rem;
    }

    header .subtitle {
        font-size: 1rem;
    }

    .panel-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .panel-actions {
        width: 100%;
    }

    .panel-actions .btn {
        flex: 1;
        justify-content: center;
    }

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

    .examples-grid {
        flex-direction: column;
    }

    .example-btn {
        width: 100%;
        text-align: center;
    }

    .editor-panel {
        min-height: 250px;
    }
}

/* Scrollbar styling */
textarea::-webkit-scrollbar {
    width: 8px;
}

textarea::-webkit-scrollbar-track {
    background: var(--background-color);
    border-radius: 4px;
}

textarea::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

textarea::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}