:root {
  --bg-color: #0D1117;
  --panel-bg: rgba(22, 27, 34, 0.85);
  --border-color: #30363D;
  --primary: #00B4D8;
  --accent: #48CAE4;
  --text-main: #E6EDF3;
  --text-muted: #8B949E;
  --hover-bg: rgba(255, 255, 255, 0.1);
  --active-bg: rgba(0, 180, 216, 0.2);
  --grid-color: rgba(255, 255, 255, 0.05);
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

/* App Layout */
.app-container {
  display: flex;
  flex: 1;
  height: calc(100vh - 80px); /* Leave room for timeline */
}

/* Shared Panel Styles */
.panel {
  background: var(--panel-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  margin-bottom: 12px;
  overflow: hidden;
}

.panel-header {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(0,0,0,0.2);
}

.panel-header h3 {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.panel-content {
  padding: 12px;
}

/* Toolbar (Left Aside) */
.toolbar {
  width: 60px;
  background: var(--panel-bg);
  backdrop-filter: blur(12px);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 16px 0;
  z-index: 10;
}

.logo {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 24px;
  text-align: center;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  transform: rotate(180deg);
  letter-spacing: 2px;
}

.tool-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
  align-items: center;
}

.separator {
  width: 32px;
  height: 1px;
  background: var(--border-color);
  margin: 16px 0;
}

.tool-btn, .action-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  width: 40px;
  height: 40px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

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

.tool-btn.active {
  background: var(--active-bg);
  color: var(--primary);
  box-shadow: inset 0 0 0 1px var(--primary);
}

/* Sidebar Right */
.sidebar-right {
  width: 250px;
  background: var(--bg-color);
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 12px;
  overflow-y: auto;
  z-index: 10;
}

/* Custom Checkbox / Toggle */
.settings-group {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: auto;
  width: 100%;
}

.settings-group select {
  background: var(--bg-color);
  color: var(--text-main);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 4px;
  font-size: 0.7rem;
  width: 48px;
  outline: none;
}

.toggle-switch {
  position: relative;
  width: 32px;
  height: 18px;
}
.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}
.slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: var(--border-color);
  transition: .3s;
  border-radius: 18px;
}
.slider:before {
  position: absolute;
  content: "";
  height: 14px;
  width: 14px;
  left: 2px;
  bottom: 2px;
  background-color: var(--text-muted);
  transition: .3s;
  border-radius: 50%;
}
input:checked + .slider {
  background-color: var(--primary);
}
input:checked + .slider:before {
  transform: translateX(14px);
  background-color: #fff;
}

/* Colors Panel */
.current-color-picker {
  display: flex;
  gap: 12px;
  margin-bottom: 12px;
}
.current-color-picker input[type="color"] {
  -webkit-appearance: none;
  border: none;
  width: 100%;
  height: 40px;
  border-radius: 6px;
  cursor: pointer;
  padding: 0;
  background: transparent;
}
.current-color-picker input[type="color"]::-webkit-color-swatch-wrapper {
  padding: 0;
}
.current-color-picker input[type="color"]::-webkit-color-swatch {
  border: 2px solid var(--border-color);
  border-radius: 6px;
}

.palette {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 6px;
}
.swatch {
  width: 100%;
  aspect-ratio: 1;
  border-radius: 4px;
  cursor: pointer;
  border: 1px solid rgba(255,255,255,0.1);
  transition: transform 0.1s;
}
.swatch:hover {
  transform: scale(1.1);
  border-color: #fff;
}

/* Layers Panel */
.layer-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.layer-item {
  display: flex;
  align-items: center;
  padding: 8px;
  background: rgba(0,0,0,0.2);
  border: 1px solid transparent;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.85rem;
}
.layer-item.active {
  background: var(--active-bg);
  border-color: var(--primary);
}
.layer-visibility {
  margin-right: 8px;
  cursor: pointer;
  opacity: 0.7;
}
.layer-visibility:hover { opacity: 1; }

/* Buttons */
.primary-btn, .secondary-btn {
  width: 100%;
  padding: 8px;
  border-radius: 6px;
  border: none;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}
.primary-btn {
  background: var(--primary);
  color: #fff;
}
.primary-btn:hover {
  background: var(--accent);
  box-shadow: 0 4px 12px rgba(0, 180, 216, 0.3);
}
.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1.2rem;
  line-height: 1;
}
.icon-btn:hover { color: var(--text-main); }

/* Main Canvas Area */
.canvas-wrapper {
  flex: 1;
  background-color: var(--bg-color);
  background-image: 
    radial-gradient(circle at center, rgba(0, 180, 216, 0.03) 0%, transparent 70%);
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden; /* We'll handle panning via transform */
  cursor: crosshair;
}

.canvas-container {
  position: relative;
  /* Pattern for transparency grid */
  background-image: 
    linear-gradient(45deg, var(--border-color) 25%, transparent 25%), 
    linear-gradient(-45deg, var(--border-color) 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, var(--border-color) 75%), 
    linear-gradient(-45deg, transparent 75%, var(--border-color) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
  box-shadow: 0 10px 40px rgba(0,0,0,0.5);
  transform-origin: center center;
  transition: transform 0.1s cubic-bezier(0.2, 0, 0, 1);
}

.canvas-container canvas {
  position: absolute;
  top: 0;
  left: 0;
  image-rendering: pixelated; /* Crucial for crisp pixels */
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.canvas-container canvas.active-layer {
  pointer-events: auto;
}

.grid-canvas {
  pointer-events: none !important;
  z-index: 1000;
  opacity: 0.5;
}

.zoom-controls {
  position: absolute;
  bottom: 20px;
  right: 20px;
  display: flex;
  align-items: center;
  background: var(--panel-bg);
  backdrop-filter: blur(12px);
  padding: 6px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  gap: 8px;
}
.zoom-controls button {
  background: transparent;
  border: none;
  color: var(--text-main);
  width: 24px; height: 24px;
  cursor: pointer;
  border-radius: 4px;
}
.zoom-controls button:hover { background: var(--hover-bg); }
#zoom-level { font-size: 0.8rem; min-width: 45px; text-align: center; }

/* Timeline (Bottom) */
.timeline {
  height: 80px;
  background: var(--panel-bg);
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  padding: 0 16px;
  z-index: 20;
}

.timeline-controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  margin-right: 24px;
  min-width: 60px;
}
.play-btn {
  font-size: 1.5rem;
  color: var(--primary);
  width: 40px; height: 40px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  background: rgba(0, 180, 216, 0.1);
  transition: all 0.2s;
}
.play-btn:hover { background: rgba(0, 180, 216, 0.2); transform: scale(1.05); }

.fps-control {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 0.7rem;
  color: var(--text-muted);
}
.fps-control input {
  width: 40px;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  border-radius: 4px;
  padding: 2px 4px;
  text-align: center;
}

.frame-list-wrapper {
  display: flex;
  flex: 1;
  overflow-x: auto;
  align-items: center;
  gap: 12px;
  padding-bottom: 4px; /* Scrollbar breathing room */
}

/* Custom Scrollbar for frame-list-wrapper */
.frame-list-wrapper::-webkit-scrollbar { height: 6px; }
.frame-list-wrapper::-webkit-scrollbar-track { background: transparent; }
.frame-list-wrapper::-webkit-scrollbar-thumb { background: var(--border-color); border-radius: 3px; }

.frame-list {
  display: flex;
  list-style: none;
  gap: 12px;
}

.frame-item {
  width: 50px;
  height: 50px;
  background: rgba(0,0,0,0.3);
  border: 2px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  position: relative;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  /* transparency grid */
  background-image: linear-gradient(45deg, var(--border-color) 25%, transparent 25%), linear-gradient(-45deg, var(--border-color) 25%, transparent 25%), linear-gradient(45deg, transparent 75%, var(--border-color) 75%), linear-gradient(-45deg, transparent 75%, var(--border-color) 75%);
  background-size: 10px 10px;
  background-position: 0 0, 0 5px, 5px -5px, -5px 0px;
}
.frame-item canvas {
  width: 100%; height: 100%; image-rendering: pixelated; object-fit: contain; pointer-events: none;
}
.frame-item.active { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(0, 180, 216, 0.2); }
.frame-number {
  position: absolute; top: 2px; left: 4px; font-size: 0.6rem;
  color: #fff; text-shadow: 0 1px 2px #000; font-weight: bold; pointer-events: none;
}
.frame-delete {
  position: absolute; top: 2px; right: 2px; font-size: 0.6rem;
  background: rgba(200,0,0,0.8); color: white; border: none;
  width: 14px; height: 14px; border-radius: 3px; cursor: pointer;
  display: none; align-items: center; justify-content: center;
}
.frame-item:hover .frame-delete { display: flex; }
.frame-item:only-child .frame-delete { display: none; }

.add-frame-btn {
  width: 50px; height: 50px; flex-shrink: 0;
  background: transparent; border: 2px dashed var(--border-color);
  border-radius: 6px; color: var(--text-muted); font-size: 1.5rem;
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  transition: all 0.2s;
}
.add-frame-btn:hover { border-color: var(--primary); color: var(--primary); background: rgba(0, 180, 216, 0.05); }

/* Remove Layer btn inside list item */
.layer-delete {
  margin-left: auto;
  background: transparent; border: none; color: var(--text-muted);
  cursor: pointer; opacity: 0; transition: opacity 0.2s;
  font-size: 1rem; line-height: 1; padding: 0 4px;
}
.layer-item:hover .layer-delete { opacity: 1; }
.layer-item:only-child .layer-delete { display: none; }

/* Input modifications for accessibility */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}