:root {
    --primary-color: #22C55E; /* Test green */
    --primary-hover: #16a34a;
    --primary-glow: rgba(34, 197, 94, 0.4);
    --bg-color: #0D1117;
    --surface-color: #161B22;
    --surface-light: #21262D;
    --text-primary: #E6EDF3;
    --text-secondary: #8B949E;
    --border-color: #30363D;
    --error-color: #F85149;
    
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Consolas, monospace;
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    justify-content: center;
}

.app-container {
    width: 100%;
    max-width: 1200px;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Header */
header {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1.5rem;
}

.header-content {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    color: var(--text-primary);
}

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

/* Main Layout */
.main-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 900px) {
    .main-content {
        grid-template-columns: 1fr 280px 1fr;
        grid-template-rows: auto;
    }
    
    .editor-section { grid-column: 1 / 2; }
    .controls-section { grid-column: 2 / 3; }
    .output-section { grid-column: 3 / 4; }
}

@media (min-width: 1200px) {
    .main-content {
        grid-template-columns: 1fr 250px 1fr;
    }
}

/* Panels */
section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    height: 100%;
}

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

.panel-header h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.editor-container {
    flex-grow: 1;
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    min-height: 400px;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.2);
    transition: var(--transition);
}

.editor-container:focus-within {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 1px var(--primary-color), 0 4px 24px var(--primary-glow);
}

textarea, pre {
    width: 100%;
    height: 100%;
    min-height: 400px;
    background: transparent;
    border: none;
    padding: 1.5rem;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.6;
    resize: none;
    outline: none;
}

textarea::placeholder {
    color: var(--text-secondary);
    opacity: 0.5;
}

.output-container {
    background-color: #0d1117; /* GitHub dark mode code bg */
    border: 1px solid var(--border-color);
}

pre {
    overflow-y: auto;
}

code {
    font-family: var(--font-mono);
}

/* Controls */
.controls-section {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    height: fit-content;
}

.control-group {
    margin-bottom: 1.5rem;
}

.control-group > label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.toggle-group {
    display: flex;
    background-color: var(--bg-color);
    border-radius: var(--radius-sm);
    padding: 0.25rem;
    border: 1px solid var(--border-color);
}

.toggle-group input[type="radio"] {
    display: none;
}

.toggle-group label {
    flex: 1;
    text-align: center;
    padding: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: calc(var(--radius-sm) - 2px);
    transition: var(--transition);
}

.toggle-group input[type="radio"]:checked + label {
    background-color: var(--surface-light);
    color: var(--text-primary);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.options {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    font-size: 0.9rem;
    user-select: none;
}

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

.checkbox-custom {
    width: 20px;
    height: 20px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--bg-color);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

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

.checkbox-label input[type="checkbox"]:checked + .checkbox-custom::after {
    content: '';
    width: 10px;
    height: 5px;
    border-bottom: 2px solid var(--bg-color);
    border-left: 2px solid var(--bg-color);
    transform: rotate(-45deg) translateY(-1px);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    outline: none;
}

.btn.primary {
    background-color: var(--primary-color);
    color: #fff;
    box-shadow: 0 4px 12px var(--primary-glow);
}

.btn.primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 6px 16px var(--primary-glow);
}

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

.btn.secondary {
    background-color: var(--surface-light);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
}

.btn.secondary:hover {
    background-color: #2D333B;
    border-color: #8B949E;
}

.full-width {
    width: 100%;
}

/* Footer */
footer {
    text-align: center;
    padding-top: 2rem;
    color: var(--text-secondary);
    font-size: 0.85rem;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background-color: var(--surface-light);
    color: var(--text-primary);
    padding: 0.75rem 1.5rem;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    font-size: 0.9rem;
    font-weight: 500;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.68, -0.55, 0.27, 1.55);
    z-index: 1000;
}

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

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

::-webkit-scrollbar-track {
    background: transparent;
}

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

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