:root {
    --bg-app: #f8fafc;
    --bg-panel: #ffffff;
    --bg-hover: #f1f5f9;
    --bg-active: #e2e8f0;

    --border-color: #e2e8f0;

    --text-primary: #0f172a;
    --text-secondary: #64748b;

    --accent: #3b82f6;
    --accent-hover: #2563eb;

    --danger: #ef4444;

    --font-ui: 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

body {
    font-family: var(--font-ui);
    background-color: var(--bg-app);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
}

.hidden {
    display: none !important;
}

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

/* Topbar */
.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1.5rem;
    height: 60px;
    background: var(--bg-panel);
    border-bottom: 1px solid var(--border-color);
    z-index: 10;
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.brand h1 {
    font-size: 1.1rem;
    font-weight: 600;
}

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

.btn {
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all 0.2s;
    font-family: var(--font-ui);
}

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

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

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

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

/* Workspace */
.workspace {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.panel {
    width: 280px;
    background: var(--bg-panel);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

.left-panel {
    border-right: 1px solid var(--border-color);
}

.right-panel {
    border-left: 1px solid var(--border-color);
}

.panel-section {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.panel-section.flex-fill {
    flex: 1;
    overflow: hidden;
    padding: 0;
    border-bottom: none;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.panel-section.flex-fill .section-header {
    padding: 1.5rem 1.5rem 0.5rem 1.5rem;
    margin-bottom: 0;
}

.section-header h2 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    font-weight: 600;
}

.icon-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
}

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

/* General Controls */
.control-group {
    margin-bottom: 1rem;
}

.control-group label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

/* Color Picker */
.color-picker-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: var(--bg-app);
    padding: 0.5rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
}

input[type="color"] {
    width: 24px;
    height: 24px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    padding: 0;
    background: none;
}

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

input[type="color"]::-webkit-color-swatch {
    border: 1px solid rgba(0, 0, 0, 0.1);
    border-radius: 4px;
}

.hex-value {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-primary);
    text-transform: uppercase;
}

/* Layers List */
.layers-list {
    flex: 1;
    overflow-y: auto;
    padding: 0.5rem;
}

.layer-item {
    display: flex;
    align-items: center;
    padding: 0.75rem;
    border-radius: 6px;
    cursor: pointer;
    gap: 0.75rem;
    border: 1px solid transparent;
}

.layer-item:hover {
    background: var(--bg-hover);
}

.layer-item.active {
    background: var(--bg-active);
    border-color: var(--border-color);
}

.layer-drag {
    color: var(--text-secondary);
    cursor: grab;
}

.layer-visibility {
    color: var(--text-primary);
}

.layer-visibility.hidden-layer {
    color: var(--text-secondary);
}

.layer-preview-swatch {
    width: 16px;
    height: 16px;
    border-radius: 4px;
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.layer-name {
    flex: 1;
    font-size: 0.85rem;
    user-select: none;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.layer-actions {
    display: flex;
    gap: 0.25rem;
    opacity: 0;
}

.layer-item:hover .layer-actions,
.layer-item.active .layer-actions {
    opacity: 1;
}

.layer-actions .icon-btn:hover {
    color: var(--danger);
    background: rgba(239, 68, 68, 0.1);
}

/* Preview Panel */
.preview-panel {
    flex: 1;
    background: var(--bg-app);
    /* Overridden by JS inline style */
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: auto;
    transition: background 0.3s;
}

.preview-box {
    width: 250px;
    height: 250px;
    background: #ffffff;
    /* Overridden by JS inline style */
    border-radius: 20px;
    transition: all 0.2s;
}

/* Properties Editor */
#properties-empty {
    text-align: center;
    padding: 2rem 0;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.properties-editor {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

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

.slider-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.slider-header label {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.val-input {
    width: 50px;
    background: var(--bg-app);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 0.25rem;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    text-align: right;
    color: var(--text-primary);
    outline: none;
}

.val-input:focus {
    border-color: var(--accent);
}

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

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    background: #fff;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    cursor: grab;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

input[type="range"]::-webkit-slider-thumb:active {
    cursor: grabbing;
    border-color: var(--accent);
}

.mb-small {
    margin-bottom: 0.25rem;
    gap: 1rem;
}

/* Toggle Switch */
.control-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.toggle-switch {
    position: relative;
    display: inline-flex;
    align-items: center;
    cursor: pointer;
    gap: 0.75rem;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: relative;
    display: inline-block;
    width: 36px;
    height: 20px;
    background-color: var(--border-color);
    border-radius: 20px;
    transition: .4s;
}

.slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 2px;
    bottom: 2px;
    background-color: white;
    border-radius: 50%;
    transition: .4s;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

input:checked+.slider {
    background-color: var(--accent);
}

input:checked+.slider:before {
    transform: translateX(16px);
}

.label-text {
    font-size: 0.85rem;
    color: var(--text-primary);
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: #1e293b;
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 100;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

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