:root {
    --bg-color: #0F172A; /* Slate 900 */
    --surface-color: rgba(30, 41, 59, 0.7); /* Slate 800 with opacity */
    --surface-hover: rgba(30, 41, 59, 0.9);
    --border-color: rgba(255, 255, 255, 0.1);
    
    --text-primary: #F8FAFC;
    --text-secondary: #94A3B8;
    
    --primary-color: #6366F1; /* Indigo 500 */
    --primary-hover: #4F46E5;
    --accent-color: #22D3EE; /* Cyan 400 */
    
    --radius: 12px;
    --transition: 0.2s ease;
    
    /* Dynamic UI vars */
    --ui-50: #EEF2FF;
    --ui-100: #E0E7FF;
    --ui-500: #6366F1;
    --ui-600: #4F46E5;
    --ui-900: #312E81;
}

[data-theme="light"] {
    --bg-color: #F8FAFC;
    --surface-color: rgba(255, 255, 255, 0.8);
    --surface-hover: rgba(255, 255, 255, 1);
    --border-color: rgba(0, 0, 0, 0.1);
    
    --text-primary: #0F172A;
    --text-secondary: #475569;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    transition: background-color var(--transition), color var(--transition);
}

.app-layout {
    display: flex;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 320px;
    background-color: var(--surface-color);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-right: 1px solid var(--border-color);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    position: sticky;
    top: 0;
    height: 100vh;
    overflow-y: auto;
}

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

.sidebar-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    background: linear-gradient(to right, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.icon-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 1.25rem;
    cursor: pointer;
    transition: color var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    border-radius: 8px;
}

.icon-btn:hover {
    color: var(--text-primary);
    background-color: rgba(255, 255, 255, 0.05);
}

/* Controls */
.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

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

.color-picker-wrapper {
    display: flex;
    gap: 1rem;
    align-items: center;
}

input[type="color"] {
    -webkit-appearance: none;
    border: none;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    cursor: pointer;
    background: none;
    padding: 0;
    overflow: hidden;
}

input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 0;
}

input[type="color"]::-webkit-color-swatch {
    border: 2px solid var(--border-color);
    border-radius: 50%;
}

input[type="text"] {
    flex: 1;
    background-color: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.75rem 1rem;
    color: var(--text-primary);
    font-family: 'Fira Code', monospace;
    font-size: 1rem;
    outline: none;
    transition: border-color var(--transition);
}

input[type="text"]:focus {
    border-color: var(--primary-color);
}

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

.slider-group label {
    display: flex;
    justify-content: space-between;
}

.slider-group span {
    color: var(--text-primary);
}

input[type="range"] {
    -webkit-appearance: none;
    width: 100%;
    height: 4px;
    background: rgba(255,255,255,0.1);
    border-radius: 2px;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: background var(--transition);
}

input[type="range"]::-webkit-slider-thumb:hover {
    background: var(--primary-hover);
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 2rem 3rem;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

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

.main-header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Palette Display */
.palette-container {
    display: grid;
    grid-template-columns: repeat(11, 1fr);
    gap: 0.5rem;
    background: var(--surface-color);
    padding: 1rem;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.shade-box {
    display: flex;
    flex-direction: column;
    border-radius: 8px;
    overflow: hidden;
    cursor: pointer;
    transition: transform 0.1s ease;
}

.shade-box:hover {
    transform: scale(1.05);
    z-index: 10;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

.shade-color {
    height: 80px;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.shade-box:hover .shade-color {
    opacity: 1;
}

.shade-info {
    padding: 0.5rem;
    text-align: center;
    background: rgba(0,0,0,0.2);
    font-size: 0.75rem;
}

.shade-name {
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: 0.25rem;
}

.shade-hex {
    font-family: 'Fira Code', monospace;
    color: var(--text-primary);
}

/* Buttons */
.primary-btn, .secondary-btn, .preview-btn-primary, .preview-btn-ghost {
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all var(--transition);
    border: none;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

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

.secondary-btn {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.secondary-btn:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.full-width {
    width: 100%;
}

.mt-2 { margin-top: 0.5rem; }
.mt-4 { margin-top: 1rem; }

/* UI Previews (using dynamic CSS vars derived from palette) */
.preview-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.glass-panel {
    background: var(--surface-color);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
}

.preview-card {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.preview-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.preview-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.amount-badge {
    font-size: 2rem;
    font-weight: 700;
    color: var(--ui-500); /* Uses custom palette var */
    margin-top: 0.5rem;
}

.preview-btn-primary {
    background-color: var(--ui-500);
    color: #fff;
    width: 100%;
}
.preview-btn-primary:hover {
    background-color: var(--ui-600);
}

.preview-btn-ghost {
    background-color: transparent;
    color: var(--ui-500);
    width: 100%;
}
.preview-btn-ghost:hover {
    background-color: var(--ui-50);
}

.card-footer {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* Alert Preview */
.alert-panel {
    background-color: var(--ui-50);
    border: 1px solid var(--ui-100);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}
.alert-icon {
    color: var(--ui-500);
    font-size: 1.5rem;
}
.alert-title {
    color: var(--ui-900);
    font-weight: 600;
    margin-bottom: 0.25rem;
}
.alert-text {
    color: var(--ui-600);
    font-size: 0.875rem;
}

/* Form Elements Preview */
.ui-elements {
    background: var(--surface-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

.preview-label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    display: block;
}

.preview-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: rgba(0,0,0,0.1);
    color: var(--text-primary);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}
.preview-input:focus {
    border-color: var(--ui-500);
    box-shadow: 0 0 0 3px var(--ui-100);
}

/* Toggle Switch */
.toggle-switch {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}
.toggle-switch input { display: none; }
.toggle-slider {
    position: relative;
    width: 44px;
    height: 24px;
    background-color: rgba(255,255,255,0.2);
    border-radius: 24px;
    cursor: pointer;
    transition: background-color var(--transition);
}
.toggle-slider::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: white;
    top: 2px;
    left: 2px;
    transition: transform var(--transition);
}
.toggle-switch input:checked + .toggle-slider {
    background-color: var(--ui-500);
}
.toggle-switch input:checked + .toggle-slider::before {
    transform: translateX(20px);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 1;
    transition: opacity var(--transition);
}
.modal.hidden {
    opacity: 0;
    pointer-events: none;
}
.modal-content {
    width: 90%;
    max-width: 600px;
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}
pre {
    background: rgba(0,0,0,0.3);
    padding: 1rem;
    border-radius: 8px;
    overflow-x: auto;
    font-family: 'Fira Code', monospace;
    font-size: 0.875rem;
    color: #e2e8f0;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--surface-color);
    color: var(--text-primary);
    padding: 1rem 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: 0 10px 15px -3px rgba(0,0,0,0.3);
    z-index: 200;
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.3s, transform 0.3s;
}
.toast.hidden {
    opacity: 0;
    transform: translateY(20px);
    pointer-events: none;
}

/* Responsiveness */
@media (max-width: 768px) {
    .app-layout {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        height: auto;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        position: static;
    }
    .main-content {
        padding: 1rem;
    }
    .palette-container {
        grid-template-columns: repeat(3, 1fr);
    }
}