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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #e0e7ff;
    --secondary-color: #64748b;
    --background: #f8fafc;
    --surface: #ffffff;
    --surface-hover: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-focus: #6366f1;
    --success: #10b981;
    --error: #ef4444;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-sm: 6px;
    --radius: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --transition: all 0.2s ease;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border-color);
    padding: 1.5rem;
    text-align: center;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.logo-img {
    width: 40px;
    height: 40px;
    object-fit: contain;
}

.logo h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    background: linear-gradient(135deg, var(--primary-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Main Content */
.main-content {
    flex: 1;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    padding: 1.5rem;
}

/* Converter Section */
.converter-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.input-panel, .output-panel {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--surface-hover);
}

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

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

#input-code {
    width: 100%;
    min-height: 300px;
    padding: 1rem 1.25rem;
    border: none;
    resize: vertical;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    background: var(--surface);
    color: var(--text-primary);
}

#input-code:focus {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--primary-light);
}

#input-code::placeholder {
    color: var(--text-muted);
}

.output-display {
    min-height: 300px;
    padding: 1rem 1.25rem;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    white-space: pre-wrap;
    word-break: break-word;
    color: var(--text-primary);
    background: var(--surface);
}

.output-display:empty::before {
    content: 'Converted code will appear here...';
    color: var(--text-muted);
}

/* Controls Section */
.controls-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.style-selectors {
    display: flex;
    align-items: flex-end;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.selector-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    min-width: 200px;
}

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

.selector-group select {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 0.95rem;
    background: var(--surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
}

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

.selector-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.arrow-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    padding-bottom: 0.5rem;
}

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

.btn-primary {
    background: var(--primary-color);
    color: white;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    margin: 0 auto;
    display: flex;
}

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

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

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

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

/* Options Section */
.options-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
    overflow: hidden;
}

.options-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.25rem;
    cursor: pointer;
    transition: var(--transition);
}

.options-header:hover {
    background: var(--surface-hover);
}

.options-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.toggle-icon {
    color: var(--text-muted);
    transition: transform 0.3s ease;
}

.options-header.active .toggle-icon {
    transform: rotate(180deg);
}

.options-content {
    display: none;
    padding: 1.25rem;
    border-top: 1px solid var(--border-color);
}

.options-content.show {
    display: block;
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 1.25rem;
}

.option-item {
    display: flex;
    align-items: center;
}

/* Custom Checkbox */
.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkbox-custom {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    position: relative;
    transition: var(--transition);
    flex-shrink: 0;
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-custom {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-custom::after {
    content: '';
    position: absolute;
    left: 6px;
    top: 2px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.custom-separator {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.custom-separator label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.custom-separator input {
    max-width: 200px;
    padding: 0.625rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 0.9rem;
    transition: var(--transition);
}

.custom-separator input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-light);
}

/* Info Section */
.info-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    padding: 1.5rem;
}

.info-section h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
    text-align: center;
}

.styles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
}

.style-card {
    background: var(--surface-hover);
    border-radius: var(--radius);
    padding: 1rem;
    text-align: center;
    transition: var(--transition);
}

.style-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.style-card h4 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.style-card code {
    display: block;
    background: var(--surface);
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.85rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    word-break: break-all;
}

.style-card p {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Footer */
.footer {
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    padding: 1.25rem;
    text-align: center;
}

.footer p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

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

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

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-primary);
    color: white;
    padding: 0.875rem 1.5rem;
    border-radius: var(--radius);
    font-size: 0.9rem;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

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

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

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

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

    .logo h1 {
        font-size: 1.5rem;
    }

    .tagline {
        font-size: 0.85rem;
    }

    .main-content {
        padding: 1rem;
    }

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

    #input-code, .output-display {
        min-height: 200px;
    }

    .style-selectors {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }

    .selector-group {
        min-width: 100%;
    }

    .arrow-icon {
        transform: rotate(90deg);
        padding: 0;
    }

    .controls-section {
        padding: 1rem;
    }

    .btn-primary {
        width: 100%;
    }

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

    .styles-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .panel-actions {
        flex-wrap: wrap;
    }

    .btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.8rem;
    }
}

@media (max-width: 480px) {
    .logo {
        flex-direction: column;
        gap: 0.5rem;
    }

    .logo-img {
        width: 32px;
        height: 32px;
    }

    .logo h1 {
        font-size: 1.25rem;
    }

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

    .panel-header {
        flex-direction: column;
        gap: 0.75rem;
        align-items: flex-start;
    }

    .panel-actions {
        width: 100%;
        justify-content: flex-start;
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.converter-section, .controls-section, .options-section, .info-section {
    animation: fadeIn 0.4s ease;
}

/* Selection */
::selection {
    background: var(--primary-light);
    color: var(--primary-color);
}

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

::-webkit-scrollbar-track {
    background: var(--surface-hover);
}

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

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}