/* CSS Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --background-color: #f8fafc;
    --surface-color: #ffffff;
    --border-color: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --success-color: #10b981;
    --error-color: #ef4444;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px 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-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --transition: 150ms ease;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
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 {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* Main Content */
main {
    flex: 1;
}

/* Options Panel */
.options-panel {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 1.25rem;
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-sm);
}

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

.option-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.option-group select {
    padding: 0.625rem 0.875rem;
    font-size: 0.9375rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background-color: var(--surface-color);
    color: var(--text-primary);
    cursor: pointer;
    transition: border-color var(--transition), box-shadow var(--transition);
    min-width: 140px;
}

.option-group select:hover {
    border-color: var(--primary-color);
}

.option-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.checkbox-group {
    flex-direction: row;
    align-items: center;
}

.checkbox-group label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    color: var(--text-primary);
}

.checkbox-group input[type="checkbox"] {
    width: 1.125rem;
    height: 1.125rem;
    accent-color: var(--primary-color);
    cursor: pointer;
}

/* Editor Container */
.editor-container {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 1rem;
    align-items: stretch;
}

.editor-panel {
    display: flex;
    flex-direction: column;
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.875rem 1rem;
    background-color: var(--background-color);
    border-bottom: 1px solid var(--border-color);
}

.panel-header h2 {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Textareas */
textarea {
    flex: 1;
    min-height: 400px;
    padding: 1rem;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', 'Consolas', monospace;
    font-size: 0.875rem;
    line-height: 1.6;
    border: none;
    resize: vertical;
    color: var(--text-primary);
    background-color: var(--surface-color);
}

textarea:focus {
    outline: none;
}

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

textarea[readonly] {
    background-color: #fafbfc;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 0.75rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    padding: 0.875rem 1.5rem;
    font-size: 1rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
}

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

.btn-primary:active {
    transform: translateY(0);
}

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

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

.btn-icon {
    font-size: 0.875rem;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    padding: 0.875rem 1.5rem;
    background-color: var(--text-primary);
    color: white;
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
    visibility: visible;
}

.toast.success {
    background-color: var(--success-color);
}

.toast.error {
    background-color: var(--error-color);
}

/* Footer */
footer {
    margin-top: 2rem;
    padding: 1.5rem 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

footer p {
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition);
}

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

/* Responsive Design */
@media (max-width: 900px) {
    .editor-container {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .action-buttons {
        flex-direction: row;
        justify-content: center;
        padding: 0.5rem 0;
    }

    textarea {
        min-height: 250px;
    }
}

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

    header h1 {
        font-size: 1.75rem;
    }

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

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

    .option-group {
        width: 100%;
    }

    .option-group select {
        width: 100%;
    }

    .panel-header {
        padding: 0.75rem;
    }

    textarea {
        min-height: 200px;
        padding: 0.75rem;
        font-size: 0.8125rem;
    }

    .btn-primary {
        width: 100%;
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #0f172a;
        --surface-color: #1e293b;
        --border-color: #334155;
        --text-primary: #f1f5f9;
        --text-secondary: #94a3b8;
    }

    .option-group select {
        background-color: var(--surface-color);
        color: var(--text-primary);
    }

    textarea {
        background-color: var(--surface-color);
        color: var(--text-primary);
    }

    textarea[readonly] {
        background-color: #162032;
    }

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

    .toast {
        background-color: var(--text-primary);
        color: var(--background-color);
    }
}