/* Style Sheet: LightMask UI (Theme-Aware, Glassmorphic, Premium Layout) */

/* Theme Variables Definition */
:root {
  /* Dark Mode (Default Theme) */
  --bg-app: #09090b;
  --bg-panel: rgba(19, 19, 22, 0.75);
  --bg-panel-rgb: 19, 19, 22;
  --text-primary: #f4f4f5;
  --text-secondary: #a1a1aa;
  --border-color: rgba(63, 63, 70, 0.4);
  --border-rgb: 63, 63, 70;
  --accent-color: #5c62f5;
  --accent-rgb: 92, 98, 245;
  --hover-bg: rgba(63, 63, 70, 0.3);
  --input-bg: #1c1c1f;
  --shadow-color: rgba(0, 0, 0, 0.6);
  --active-glow: rgba(92, 98, 245, 0.4);
  
  --base-color: #f43f5e;
  --overlay-color: #3b82f6;
  
  --font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body.light-theme {
  /* Light Mode Overrides */
  --bg-app: #f4f4f5;
  --bg-panel: rgba(255, 255, 255, 0.85);
  --bg-panel-rgb: 255, 255, 255;
  --text-primary: #18181b;
  --text-secondary: #71717a;
  --border-color: rgba(228, 228, 231, 0.8);
  --border-rgb: 228, 228, 231;
  --accent-color: #3b42e3;
  --accent-rgb: 59, 66, 227;
  --hover-bg: rgba(228, 228, 231, 0.5);
  --input-bg: #e4e4e7;
  --shadow-color: rgba(0, 0, 0, 0.08);
  --active-glow: rgba(59, 66, 227, 0.2);
  
  --base-color: #e11d48;
  --overlay-color: #2563eb;
}

/* Global Reset & Box Sizing */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  user-select: none;
}

body {
  background-color: var(--bg-app);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 14px;
  overflow: hidden;
  height: 100vh;
  width: 100vw;
  transition: background-color 0.3s cubic-bezier(0.4, 0, 0.2, 1), color 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

/* 1. Header Styling */
.app-header {
  height: 52px;
  background-color: rgba(var(--bg-panel-rgb), 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  z-index: 10;
  position: relative;
}

/* Undo/redo group, absolutely centered in the header so it lines up with the
   center canvas (the two sidebars are equal width). */
.header-center {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 17px;
  letter-spacing: 0.5px;
  color: var(--text-primary);
}

.logo-icon {
  color: var(--accent-color);
  filter: drop-shadow(0 0 4px var(--active-glow));
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  width: 36px;
  height: 36px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
}

.header-btn:hover:not(:disabled) {
  color: var(--text-primary);
  background-color: var(--hover-bg);
}

.header-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.vertical-divider {
  width: 1px;
  height: 20px;
  background-color: var(--border-color);
  margin: 0 4px;
}

/* 2. Workspace Layout */
.app-workspace {
  flex: 1;
  display: flex;
  height: calc(100vh - 52px);
  position: relative;
}

/* Left Sidebar (Layers & Cards) */
.sidebar-left {
  width: 280px;
  background-color: var(--bg-panel);
  backdrop-filter: blur(20px);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 16px;
  gap: 16px;
  z-index: 5;
  box-shadow: 2px 0 10px var(--shadow-color);
  overflow-y: auto;
}

.panel-section-title {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-secondary);
  margin-bottom: 8px;
  text-align: center;
  width: 100%;
}

.toolbar-tools {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
  padding: 0 10px;
}

/* Horizontal tools layout for right sidebar */
.sidebar-right .toolbar-tools {
  display: flex;
  flex-direction: row;
  gap: 8px;
  width: 100%;
  padding: 0;
}

.sidebar-right .tool-btn {
  width: auto;
  aspect-ratio: 1;
  flex: 1;
}

.tool-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 100%;
  aspect-ratio: 1;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: var(--font-family);
  font-size: 10px;
  font-weight: 500;
}

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

.tool-btn.active {
  color: #ffffff;
  background-color: var(--accent-color);
  border-color: rgba(255, 255, 255, 0.15);
  box-shadow: 0 4px 12px var(--active-glow);
}

/* Brush Settings Panel under tools */
#brush-settings {
  display: flex;
  flex-direction: column;
  gap: 12px;
  animation: slideUp 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

#brush-settings.closed {
  display: none;
}

/* Viewport (Center) */
.viewport-container {
  flex: 1;
  position: relative;
  background-color: var(--bg-app);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.canvas-wrapper {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: default;
  /* Checkerboard transparency background */
  background-image: 
    linear-gradient(45deg, rgba(var(--border-rgb), 0.1) 25%, transparent 25%), 
    linear-gradient(-45deg, rgba(var(--border-rgb), 0.1) 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, rgba(var(--border-rgb), 0.1) 75%), 
    linear-gradient(-45deg, transparent 75%, rgba(var(--border-rgb), 0.1) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

canvas#editor-canvas {
  width: 100%;
  height: 100%;
  display: block;
  image-rendering: pixelated; /* sharp rendering on zoom */
}

/* Upload Interface Overlays */
.upload-overlay {
  position: absolute;
  inset: 0;
  background-color: var(--bg-app);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 8;
  padding: 24px;
}

.upload-card {
  width: 100%;
  max-width: 480px;
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 32px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  box-shadow: 0 20px 50px var(--shadow-color);
  backdrop-filter: blur(20px);
}

.upload-icon {
  color: var(--accent-color);
  margin-bottom: 20px;
  filter: drop-shadow(0 4px 8px var(--active-glow));
}

.upload-card h2 {
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 8px;
}

.upload-card p {
  color: var(--text-secondary);
  font-size: 13px;
  margin-bottom: 28px;
  line-height: 1.5;
}

.file-inputs {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 24px;
}

.file-input-wrapper {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 6px;
}

.file-label {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 46px;
  border-radius: 12px;
  border: 1px dashed var(--border-color);
  cursor: pointer;
  font-weight: 500;
  transition: all 0.2s ease;
  background-color: var(--hover-bg);
}

.file-label:hover {
  background-color: rgba(var(--border-rgb), 0.2);
}

.file-label.base-color:hover {
  border-color: var(--base-color);
  color: var(--base-color);
}

.file-label.overlay-color:hover {
  border-color: var(--overlay-color);
  color: var(--overlay-color);
}

.file-label input {
  display: none;
}

.file-status {
  font-size: 11px;
  color: var(--text-secondary);
  text-align: right;
  padding-right: 4px;
}

.demo-btn {
  background: transparent;
  border: 1px solid var(--accent-color);
  color: var(--accent-color);
  padding: 10px 24px;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
  font-family: var(--font-family);
  font-size: 13px;
  transition: all 0.2s ease;
  width: 100%;
  margin-top: 10px;
}

.demo-btn:hover {
  background-color: var(--accent-color);
  color: #ffffff;
  box-shadow: 0 4px 12px var(--active-glow);
}

/* Viewport HUD Elements */
.viewport-hud {
  position: absolute;
  bottom: 20px;
  left: 20px;
  background-color: rgba(var(--bg-panel-rgb), 0.85);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 4px 8px;
  display: flex;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.3);
  font-weight: 600;
}

#hud-zoom {
  padding: 0 4px;
  font-size: 12px;
  min-width: 44px;
}

.viewport-hud button {
  background: var(--input-bg);
  border: none;
  color: var(--text-primary);
  padding: 4px 10px;
  font-size: 11px;
  font-weight: 600;
  border-radius: 4px;
  cursor: pointer;
  font-family: var(--font-family);
}

.viewport-hud button:hover {
  background-color: var(--hover-bg);
}

.viewport-mask-hud {
  position: absolute;
  top: 20px;
  left: 20px;
  background-color: rgba(var(--bg-panel-rgb), 0.85);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 8px 12px;
  display: flex;
  align-items: center;
  box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

.hud-checkbox {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: 12px;
  font-weight: 500;
  color: var(--text-primary);
}

.hud-checkbox input {
  accent-color: var(--accent-color);
  width: 14px;
  height: 14px;
}

/* Right Sidebar (Layers & Cards) */
.sidebar-right {
  width: 280px;
  background-color: var(--bg-panel);
  backdrop-filter: blur(20px);
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 16px;
  gap: 16px;
  z-index: 5;
  box-shadow: -2px 0 10px var(--shadow-color);
  overflow-y: auto;
}

.panel-card {
  background-color: rgba(var(--bg-panel-rgb), 0.4);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 14px;
}

/* File info cards */
.file-panel {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.loaded-files-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.file-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--input-bg);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 11px;
  border: 1px solid transparent;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.file-row:hover {
  border-color: rgba(var(--border-rgb), 0.5);
  cursor: pointer;
}

.file-row.active {
  background-color: rgba(var(--accent-rgb), 0.1);
  border-color: var(--accent-color);
  box-shadow: 0 4px 10px rgba(var(--accent-rgb), 0.05);
}

.file-row.active .file-row-label {
  color: var(--accent-color);
}

.file-row-label {
  color: var(--text-secondary);
  font-weight: 600;
}

.file-row-name {
  flex: 1;
  text-align: left;
  margin-left: 6px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: var(--text-primary);
}

.file-reload-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2px;
  border-radius: 4px;
}

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

/* Visibility Buttons inside Files Panel */
.file-visibility-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px;
  border-radius: 4px;
  margin-right: 6px;
  transition: all 0.2s ease;
}

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

.file-visibility-btn.muted {
  opacity: 0.3;
}

/* Overlay Opacity Slider Group */
.overlay-opacity-group {
  margin-top: 8px;
  padding: 12px 0 4px 0;
  border-top: 1px solid var(--border-color);
}

.export-btn {
  background-color: var(--accent-color);
  border: none;
  color: #ffffff;
  height: 40px;
  border-radius: 8px;
  font-family: var(--font-family);
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 4px 12px var(--active-glow);
}

.export-btn:hover:not(:disabled) {
  opacity: 0.9;
  transform: translateY(-1px);
}

.export-btn:disabled {
  background-color: var(--hover-bg);
  color: var(--text-secondary);
  cursor: not-allowed;
  box-shadow: none;
}

.app-header .export-btn {
  height: 32px;
  padding: 0 14px;
  font-size: 12px;
  border-radius: 6px;
  font-weight: 600;
  box-shadow: 0 2px 8px var(--active-glow);
}

/* Custom Sliders & Form Fields */
.slider-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.slider-label {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.slider-label span:nth-child(2) {
  color: var(--text-primary);
}

/* Range input styling */
input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  height: 3px;
  background: linear-gradient(to right, var(--accent-color) var(--value-percent, 0%), var(--input-bg) var(--value-percent, 0%));
  border-radius: 1.5px;
  outline: none;
  margin: 8px 0;
}

input[type="range"]::-webkit-slider-runnable-track {
  background: transparent;
  height: 3px;
}

/* Firefox support for progress bar fill */
input[type="range"]::-moz-range-track {
  background: transparent;
  height: 3px;
}

input[type="range"]::-moz-range-progress {
  background-color: var(--accent-color);
  height: 3px;
  border-radius: 1.5px;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 12px;
  height: 16px;
  background-color: transparent;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 32'><path d='M12 2 C12 2, 22 14, 22 20 A 10 10 0 0 1 2 20 C2 14, 12 2, 12 2 Z' fill='%23f8fafc' stroke='%233b82f6' stroke-width='2.5'/></svg>");
  background-repeat: no-repeat;
  background-position: center;
  background-size: contain;
  cursor: pointer;
  margin-top: -8.5px;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.25));
  transition: all 0.15s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

/* Firefox support for teardrop thumb */
input[type="range"]::-moz-range-thumb {
  width: 12px;
  height: 16px;
  border: none;
  background-color: transparent;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 32'><path d='M12 2 C12 2, 22 14, 22 20 A 10 10 0 0 1 2 20 C2 14, 12 2, 12 2 Z' fill='%23f8fafc' stroke='%233b82f6' stroke-width='2.5'/></svg>");
  background-repeat: no-repeat;
  background-position: center;
  background-size: contain;
  cursor: pointer;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.25));
  transition: all 0.15s ease;
}

input[type="range"]::-moz-range-thumb:hover {
  transform: scale(1.15);
}

/* Theme overrides for light mode */
.light-theme input[type="range"]::-webkit-slider-thumb {
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 32'><path d='M12 2 C12 2, 22 14, 22 20 A 10 10 0 0 1 2 20 C2 14, 12 2, 12 2 Z' fill='%230f172a' stroke='%236366f1' stroke-width='2.5'/></svg>");
}

.light-theme input[type="range"]::-moz-range-thumb {
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 32'><path d='M12 2 C12 2, 22 14, 22 20 A 10 10 0 0 1 2 20 C2 14, 12 2, 12 2 Z' fill='%230f172a' stroke='%236366f1' stroke-width='2.5'/></svg>");
}

/* Radio button styles */
.brush-mode-selector {
  display: flex;
  background: var(--input-bg);
  padding: 3px;
  border-radius: 8px;
  margin-top: 4px;
}

.radio-btn {
  flex: 1;
  text-align: center;
  cursor: pointer;
}

.radio-btn input {
  display: none;
}

.radio-btn span {
  display: block;
  padding: 6px;
  border-radius: 6px;
  font-size: 11px;
  font-weight: 600;
  color: var(--text-secondary);
  transition: all 0.2s ease;
}

.radio-btn.active span {
  background-color: var(--bg-app);
  color: var(--text-primary);
  box-shadow: 0 2px 5px var(--shadow-color);
}

/* Layers list panel styling */
.layers-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 200px;
}

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

.add-layer-btn {
  background: var(--input-bg);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-weight: 600;
  font-size: 11px;
  height: 28px;
  padding: 0 10px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  white-space: nowrap;
}

.add-layer-btn:hover:not(:disabled) {
  background-color: var(--hover-bg);
}

.add-layer-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.add-mask-dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: calc(100% + 4px);
  right: 0;
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 4px;
  width: 140px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  box-shadow: 0 10px 25px var(--shadow-color);
  backdrop-filter: blur(20px);
  z-index: 15;
  display: none; /* controlled programmatically */
}

.dropdown-menu.show {
  display: flex;
}

.menu-item {
  background: transparent;
  border: none;
  color: var(--text-primary);
  text-align: left;
  padding: 6px 10px;
  font-size: 12px;
  font-weight: 500;
  border-radius: 4px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-family);
}

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

.layers-empty-state {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--text-secondary);
  font-size: 12px;
  border: 1px dashed var(--border-color);
  border-radius: 8px;
}

.layers-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  overflow-y: auto;
  max-height: 350px;
  padding-right: 4px;
}

/* Custom Scrollbar for Layers */
.layers-list::-webkit-scrollbar {
  width: 4px;
}

.layers-list::-webkit-scrollbar-track {
  background: transparent;
}

.layers-list::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 2px;
}

/* Layer row styling */
.layer-row {
  display: flex;
  align-items: center;
  background-color: var(--input-bg);
  border: 1px solid transparent;
  border-radius: 8px;
  padding: 8px 10px;
  cursor: pointer;
  transition: all 0.2s ease;
  gap: 8px;
}

.layer-row:hover {
  border-color: rgba(var(--border-rgb), 0.5);
}

.layer-row.active {
  background-color: rgba(var(--accent-rgb), 0.1);
  border-color: var(--accent-color);
  box-shadow: 0 4px 10px rgba(var(--accent-rgb), 0.05);
}

.layer-drag-handle {
  color: var(--text-secondary);
  cursor: grab;
  display: flex;
  align-items: center;
}

.layer-icon {
  color: var(--text-secondary);
  display: flex;
  align-items: center;
}

.layer-row.active .layer-icon {
  color: var(--accent-color);
}

.layer-name-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 13px;
  font-weight: 500;
  outline: none;
  min-width: 0;
}

.layer-name-input:read-only {
  cursor: pointer;
}

.layer-name-input:focus {
  background-color: var(--bg-app);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

.layer-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

.layer-action-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  width: 24px;
  height: 24px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

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

.layer-action-btn.danger-hover:hover {
  color: #ef4444;
  background-color: rgba(239, 68, 68, 0.1);
}

.layer-action-btn.active {
  color: var(--accent-color);
}

/* Mask group (a "mask layer" that holds child components) */
.mask-group {
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background-color: rgba(var(--border-rgb), 0.06);
  overflow: visible;
}

.mask-group.active {
  border-color: var(--accent-color);
  box-shadow: 0 4px 10px rgba(var(--accent-rgb), 0.05);
}

.mask-group-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  cursor: pointer;
  border-radius: 8px 8px 0 0;
  position: relative;
}

.mask-group-header:hover {
  background-color: var(--hover-bg);
}

.mask-group.active .mask-group-header .layer-icon {
  color: var(--accent-color);
}

/* Child component rows nested under a group, indented with a guide rail to
   show they belong to the mask above them. */
.mask-children {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 4px 8px 8px 24px;
  position: relative;
}

.mask-children::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 10px;
  left: 14px;
  width: 1px;
  background-color: var(--border-color);
}

.mask-children:empty {
  display: none;
}

.child-row {
  padding: 6px 8px;
  background-color: var(--input-bg);
}

/* The add-component dropdown. Appended to <body> and positioned in JS so it
   escapes both the layers list's overflow clipping and any backdrop-filter
   ancestor that would otherwise capture its fixed positioning. */
.add-child-menu {
  position: fixed;
  top: auto;
  right: auto;
  left: auto;
  z-index: 1000;
}

/* Layer adjustments panel */
.details-panel {
  display: flex;
  flex-direction: column;
  gap: 14px;
  animation: slideUp 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.custom-checkbox-container {
  display: flex;
  align-items: center;
  position: relative;
  padding-left: 26px;
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.custom-checkbox-container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

.checkmark {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  left: 0;
  height: 16px;
  width: 16px;
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  transition: all 0.2s ease;
}

.custom-checkbox-container:hover input ~ .checkmark {
  border-color: var(--accent-color);
}

.custom-checkbox-container input:checked ~ .checkmark {
  background-color: var(--accent-color);
  border-color: var(--accent-color);
}

.checkmark:after {
  content: "";
  position: absolute;
  display: none;
  left: 5px;
  top: 2px;
  width: 4px;
  height: 8px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.custom-checkbox-container input:checked ~ .checkmark:after {
  display: block;
}

.custom-checkbox-container input:checked ~ span:last-child {
  color: var(--text-primary);
}

.selected-mask-info {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  padding-top: 10px;
  margin-top: 4px;
}

.info-label {
  font-weight: 500;
}

.info-val {
  font-weight: 700;
  text-transform: capitalize;
  color: var(--text-primary);
}

/* Blend Mode Segmented Control */
.mode-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.mode-label {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.segmented-control {
  display: flex;
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 2px;
  gap: 2px;
}

.segmented-control .segment {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 11px;
  font-weight: 600;
  padding: 5px 4px;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.segmented-control .segment:hover {
  color: var(--text-primary);
}

.segmented-control .segment.active {
  background-color: var(--accent-color);
  color: #fff;
}

.mode-group.disabled {
  opacity: 0.45;
  pointer-events: none;
}

/* Per-row blend mode badge */
.mode-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  height: 16px;
  margin-left: 2px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 700;
  line-height: 1;
  flex-shrink: 0;
  background-color: rgba(var(--accent-rgb), 0.15);
  color: var(--accent-color);
}

.mode-badge.mode-subtract {
  background-color: rgba(239, 68, 68, 0.15);
  color: #ef4444;
}

.mode-badge.mode-intersect {
  background-color: rgba(234, 179, 8, 0.18);
  color: #eab308;
}

/* Animations */
@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Drag and Drop Canvas Overlay & Zones */
.canvas-drop-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  background-color: rgba(var(--bg-panel-rgb), 0.7);
  backdrop-filter: blur(15px);
  z-index: 100;
  animation: fadeIn 0.2s ease;
}

.canvas-drop-overlay * {
  pointer-events: none;
}

.drop-zone-half {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 3px dashed transparent;
  margin: 20px;
  border-radius: 16px;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  color: var(--text-secondary);
  text-align: center;
  background-color: rgba(var(--bg-panel-rgb), 0.3);
}

.drop-zone-half h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 12px 0 6px 0;
  color: var(--text-primary);
}

.drop-zone-half p {
  font-size: 12px;
  opacity: 0.8;
}

.drop-zone-half svg {
  transition: transform 0.25s ease;
}

/* Specific Zone Highlights */
.drop-zone-left {
  border-color: rgba(244, 63, 94, 0.2);
}
.drop-zone-left.drag-over {
  border-color: var(--base-color);
  background-color: rgba(244, 63, 94, 0.1);
  color: var(--base-color);
  box-shadow: 0 0 30px rgba(244, 63, 94, 0.2);
}
.drop-zone-left.drag-over svg {
  color: var(--base-color);
  transform: scale(1.2);
}

.drop-zone-right {
  border-color: rgba(59, 130, 246, 0.2);
}
.drop-zone-right.drag-over {
  border-color: var(--overlay-color);
  background-color: rgba(59, 130, 246, 0.1);
  color: var(--overlay-color);
  box-shadow: 0 0 30px rgba(59, 130, 246, 0.2);
}
.drop-zone-right.drag-over svg {
  color: var(--overlay-color);
  transform: scale(1.2);
}

/* Sidebar Draggable File Rows */
.file-row[draggable="true"] {
  cursor: grab;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.file-row.dragging {
  opacity: 0.4;
  border: 1px dashed var(--border-color);
  background-color: var(--bg-app);
  transform: scale(0.98);
}

.file-row.drag-over {
  border: 1px dashed var(--accent-color) !important;
  background-color: rgba(var(--accent-rgb), 0.18) !important;
  box-shadow: 0 0 12px var(--active-glow) !important;
  transform: scale(1.03);
  z-index: 2;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}