/* ============================================
   PARTICULA — Particle Sandbox
   ============================================ */
:root {
  --bg: #08090f;
  --bg-2: #0d1018;
  --panel: rgba(14, 18, 30, 0.92);
  --panel-solid: #0e121e;
  --panel-2: #161d2f;
  --panel-3: #1c2540;
  --border: rgba(255, 255, 255, 0.06);
  --border-light: rgba(255, 255, 255, 0.1);
  --text: #e8eaf0;
  --text-dim: #b0b8cc;
  --muted: #6b7a96;
  --accent: #f7a828;
  --accent-soft: rgba(247, 168, 40, 0.15);
  --accent-glow: rgba(247, 168, 40, 0.35);
  --good: #34d399;
  --danger: #f87171;
  --info: #60a5fa;
  --shadow: 0 8px 32px rgba(0,0,0,0.5);
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --radius: 10px;
  --radius-sm: 6px;
  --glass: saturate(1.8) blur(16px);
  --sai-top: env(safe-area-inset-top, 0px);
  --sai-right: env(safe-area-inset-right, 0px);
  --sai-bottom: env(safe-area-inset-bottom, 0px);
  --sai-left: env(safe-area-inset-left, 0px);
}

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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: 'Poppins', 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
  font-size: 14px;
  -webkit-tap-highlight-color: transparent;
  touch-action: none;
  user-select: none;
}

/* ---- Animations ---- */
@keyframes swatch-pop {
  0% { transform: scale(1); }
  50% { transform: scale(1.25); }
  100% { transform: scale(1); }
}
@keyframes selected-glow {
  0%, 100% { box-shadow: 0 0 12px rgba(247, 168, 40, 0.15), inset 0 0 8px rgba(247, 168, 40, 0.05); }
  50% { box-shadow: 0 0 22px rgba(247, 168, 40, 0.28), inset 0 0 14px rgba(247, 168, 40, 0.1); }
}

/* ---- Toolbar Home & Title ---- */
.toolbar-home {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-size: 16px;
  transition: all 0.15s;
  background: transparent;
  border: 1px solid transparent;
}
.toolbar-home:hover {
  background: var(--panel-2);
  border-color: var(--border-light);
  transform: scale(1.08);
}
.toolbar-home:active {
  transform: scale(0.95);
}
.toolbar-title {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  background: linear-gradient(135deg, var(--text), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
}

/* ---- App Layout ---- */
#app {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
  padding-top: var(--sai-top);
  padding-bottom: var(--sai-bottom);
}

/* ---- Toolbar ---- */
#toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 50px;
  min-height: 50px;
  padding: 0 16px;
  background: linear-gradient(180deg, var(--panel), var(--panel-solid));
  backdrop-filter: var(--glass);
  -webkit-backdrop-filter: var(--glass);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 1px 0 rgba(247, 168, 40, 0.06), 0 4px 16px rgba(0,0,0,0.3);
  gap: 10px;
  z-index: 100;
  position: relative;
}
#toolbar::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.06), rgba(247,168,40,0.12), rgba(255,255,255,0.06), transparent);
  pointer-events: none;
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 6px;
}
.toolbar-left {
  gap: 4px;
}

.toolbar-center {
  flex: 1;
  justify-content: center;
  max-width: 300px;
  gap: 10px;
}

.tool-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 16px;
  transition: all 0.15s;
}
.tool-btn svg {
  pointer-events: none;
  transition: transform 0.15s;
}
.tool-btn:hover {
  background: linear-gradient(180deg, var(--panel-2), var(--panel-3));
  color: var(--text);
  border-color: var(--border-light);
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}
.tool-btn:hover svg {
  transform: scale(1.12);
}
.tool-btn.active {
  background: linear-gradient(135deg, var(--accent), #e08a10);
  color: #0a0a0a;
  border-color: transparent;
  box-shadow: 0 2px 12px var(--accent-glow);
  font-weight: 700;
  text-shadow: 0 1px 2px rgba(0,0,0,0.2);
}
.tool-btn.active:active {
  box-shadow: 0 1px 4px var(--accent-glow);
  transform: translateY(1px);
}
.tool-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}
.tool-btn:focus-visible,
.elem-btn:focus-visible,
.mobile-elem-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.tool-sep {
  width: 1px;
  height: 20px;
  background: var(--border-light);
  margin: 0 2px;
  flex-shrink: 0;
}

/* Selected element indicator */
.selected-elem-indicator {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 5px 14px 5px 7px;
  background: linear-gradient(135deg, var(--bg-2), var(--panel-2));
  border: 1px solid var(--border-light);
  border-radius: 20px;
  cursor: default;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.04), 0 2px 6px rgba(0,0,0,0.2);
}
.sel-swatch {
  width: 18px;
  height: 18px;
  border-radius: 5px;
  border: 1.5px solid rgba(255,255,255,0.2);
  box-shadow: 0 0 8px rgba(255,255,255,0.05);
  transition: transform 0.25s ease;
}
.sel-swatch.pop {
  animation: swatch-pop 0.25s ease;
}
.sel-name {
  font-size: 12px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 0.03em;
}

/* Brush slider */
.brush-label {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 12px;
  cursor: default;
}
.brush-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 120px;
  height: 4px;
  border-radius: 2px;
  background: var(--panel-3);
  outline: none;
  cursor: pointer;
}
.brush-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
  box-shadow: 0 0 8px var(--accent-glow);
  transition: transform 0.1s;
}
.brush-slider::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}
.brush-slider::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
}
.brush-val {
  min-width: 20px;
  text-align: center;
  color: var(--accent);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

/* Brush shape buttons */
.brush-shapes {
  display: flex;
  gap: 2px;
}
.shape-btn {
  width: 26px;
  height: 26px;
  border: 1px solid transparent;
  border-radius: 4px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}
.shape-btn:hover {
  background: var(--panel-2);
  color: var(--text);
}
.shape-btn.active {
  background: var(--accent-soft);
  color: var(--accent);
  border-color: var(--accent);
}

/* Speed slider */
.speed-label {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--muted);
  font-size: 12px;
  cursor: default;
}
.speed-icon {
  font-size: 14px;
}
.speed-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 80px;
  height: 4px;
  border-radius: 2px;
  background: var(--panel-3);
  outline: none;
  cursor: pointer;
}
.speed-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
  box-shadow: 0 0 6px var(--accent-glow);
}
.speed-slider::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
}
.speed-val {
  min-width: 28px;
  text-align: center;
  color: var(--accent);
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
}

.fps-counter {
  font-size: 10px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  min-width: 52px;
  text-align: right;
  font-weight: 600;
  letter-spacing: 0.03em;
}

/* ---- Main Layout ---- */
#main {
  flex: 1;
  display: flex;
  overflow: hidden;
  position: relative;
}

/* ---- Sidebar ---- */
#sidebar {
  width: 230px;
  min-width: 230px;
  background: var(--panel-solid);
  background-image:
    linear-gradient(rgba(255,255,255,0.012) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.012) 1px, transparent 1px);
  background-size: 24px 24px;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: margin-left 0.3s ease, opacity 0.3s ease;
  z-index: 50;
}
#sidebar.collapsed {
  margin-left: -230px;
  opacity: 0;
  pointer-events: none;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 16px 12px;
  border-bottom: 2px solid transparent;
  border-image: linear-gradient(90deg, var(--accent), rgba(247,168,40,0.1), transparent) 1;
  background: linear-gradient(180deg, rgba(247, 168, 40, 0.04) 0%, transparent 100%);
  position: relative;
}
.sidebar-header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60%;
  height: 1px;
  background: linear-gradient(90deg, var(--accent-glow), transparent);
  pointer-events: none;
}
.sidebar-header h2 {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  background: linear-gradient(135deg, var(--text) 30%, var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.sidebar-toggle {
  background: none;
  border: none;
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
  padding: 4px 6px;
  border-radius: 4px;
  transition: all 0.15s;
}
.sidebar-toggle:hover {
  color: var(--accent);
  background: var(--accent-soft);
}

#elementCategories {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 6px 10px;
  scrollbar-width: thin;
  scrollbar-color: var(--panel-3) transparent;
}
#elementCategories::-webkit-scrollbar {
  width: 4px;
}
#elementCategories::-webkit-scrollbar-track {
  background: transparent;
}
#elementCategories::-webkit-scrollbar-thumb {
  background: var(--panel-3);
  border-radius: 2px;
}

/* Element category */
.elem-category {
  margin-bottom: 2px;
}
.elem-category + .elem-category {
  border-top: 1px solid var(--border);
  margin-top: 4px;
  padding-top: 4px;
}
.elem-category-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 8px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
  cursor: pointer;
  border-radius: var(--radius-sm);
  border-left: 2px solid transparent;
  transition: all 0.15s;
}
.elem-category-header:hover {
  background: rgba(255,255,255,0.03);
  color: var(--text-dim);
  border-left-color: var(--accent);
  padding-left: 6px;
}
.elem-category-header .cat-arrow {
  font-size: 8px;
  transition: transform 0.25s ease;
  opacity: 0.5;
}
.elem-category-header.collapsed .cat-arrow {
  transform: rotate(-90deg);
}

.elem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 4px;
  padding: 4px 0 6px;
  max-height: 600px;
  overflow: hidden;
  transition: max-height 0.3s ease, opacity 0.2s ease, padding 0.3s ease;
  opacity: 1;
}
.elem-grid.hidden {
  max-height: 0;
  opacity: 0;
  padding: 0;
}

/* Element button */
.elem-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding: 8px 4px 6px;
  border: 1.5px solid rgba(255,255,255,0.04);
  border-radius: var(--radius);
  background: linear-gradient(180deg, var(--bg-2), rgba(8, 9, 15, 0.8));
  cursor: pointer;
  transition: all 0.2s ease, transform 0.1s;
  position: relative;
}
.elem-btn::before {
  content: '';
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  background: linear-gradient(135deg, transparent, rgba(255,255,255,0.03));
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.2s;
}
.elem-btn:hover::before {
  opacity: 1;
}
.elem-btn:hover {
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border-color: var(--border-light);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.4), 0 0 15px var(--el-glow, rgba(255,255,255,0.03));
}
.elem-btn:active {
  transform: translateY(0) scale(0.96);
}
.elem-btn.selected {
  border-color: var(--accent);
  background: linear-gradient(180deg, var(--accent-soft), rgba(247, 168, 40, 0.08));
  animation: selected-glow 2s ease-in-out infinite;
}

/* Element swatch — flexbox centered */
.elem-swatch {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  box-shadow: 0 3px 8px rgba(0,0,0,0.4), inset 0 -1px 2px rgba(0,0,0,0.2);
  position: relative;
}
/* Radial highlight for glass-like effect */
.elem-swatch::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(circle at 30% 30%, rgba(255,255,255,0.18), transparent 60%);
  pointer-events: none;
  z-index: 3;
}

/* Icon inside swatch */
.elem-swatch .elem-icon {
  z-index: 2;
  flex-shrink: 0;
}
img.elem-icon {
  width: 24px;
  height: 24px;
  object-fit: contain;
  filter: drop-shadow(0 1px 2px rgba(0,0,0,0.5)) brightness(1.15);
}

.elem-name {
  font-size: 9px;
  font-weight: 600;
  color: var(--text-dim);
  text-align: center;
  line-height: 1.1;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.elem-btn.selected .elem-name {
  color: var(--accent);
  font-weight: 700;
}

/* Premade icons */
.premade-icon {
  font-size: 20px;
  line-height: 1;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.premade-grid {
  grid-template-columns: repeat(3, 1fr);
}

/* Sidebar footer */
.sidebar-footer {
  padding: 10px 14px;
  border-top: 2px solid transparent;
  border-image: linear-gradient(90deg, transparent, var(--accent), transparent) 1;
  font-size: 11px;
  color: var(--muted);
  background: linear-gradient(180deg, rgba(0,0,0,0.1), rgba(0,0,0,0.35));
  position: relative;
}
.sidebar-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 20%;
  right: 20%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent-glow), transparent);
  pointer-events: none;
}
.hover-info, .temp-display, .particle-count {
  display: flex;
  justify-content: space-between;
  padding: 3px 0;
}
.info-label, .temp-label, .count-label {
  font-weight: 500;
}
.info-value, .temp-value, .count-value {
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--text);
  transition: color 0.3s, text-shadow 0.3s;
}
.info-value {
  color: var(--accent);
}
.count-value.count-active {
  color: var(--good);
  text-shadow: 0 0 8px rgba(52, 211, 153, 0.4);
}

/* ---- Canvas ---- */
#canvasWrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #040408;
  position: relative;
  overflow: hidden;
}
/* Faint dot-grid texture */
#canvasWrap::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255,255,255,0.015) 1px, transparent 1px);
  background-size: 20px 20px;
  pointer-events: none;
  z-index: 0;
}
/* Radial vignette */
#canvasWrap::after {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(ellipse at center, transparent 50%, rgba(0,0,0,0.45) 100%);
  box-shadow: inset 0 0 120px rgba(0,0,0,0.5);
  z-index: 1;
}

#sandCanvas {
  image-rendering: pixelated;
  image-rendering: crisp-edges;
  cursor: crosshair;
  display: block;
  border: 1px solid rgba(255,255,255,0.04);
  box-shadow: 0 0 20px rgba(0,0,0,0.6), 0 0 60px rgba(0,0,0,0.3);
  position: relative;
  z-index: 1;
}

.canvas-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 30;
  transition: opacity 0.3s;
}
.canvas-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

/* ---- Mobile Bottom Bar ---- */
#mobileBar {
  display: none;
  height: 58px;
  min-height: 58px;
  background: var(--panel);
  backdrop-filter: var(--glass);
  -webkit-backdrop-filter: var(--glass);
  border-top: 1px solid rgba(255,255,255,0.08);
  box-shadow: 0 -4px 20px rgba(0,0,0,0.3);
  align-items: center;
  padding: 0 8px;
  gap: 4px;
  z-index: 100;
}

.mobile-elements {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 5px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  padding: 4px 0;
}
.mobile-elements::-webkit-scrollbar {
  display: none;
}

.mobile-elem-btn {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  border: 1.5px solid var(--border);
  border-radius: 20px;
  background: var(--bg-2);
  color: var(--text-dim);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s;
}
.mobile-elem-btn.selected {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
  box-shadow: 0 0 16px rgba(247, 168, 40, 0.2);
}
.mobile-elem-swatch {
  width: 18px;
  height: 18px;
  border-radius: 5px;
  border: 1px solid rgba(255,255,255,0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.mobile-elem-swatch .mobile-icon {
  width: 14px;
  height: 14px;
  object-fit: contain;
  filter: drop-shadow(0 1px 1px rgba(0,0,0,0.4)) brightness(1.1);
}

.mobile-replace-btn {
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--bg-2);
  color: var(--text-dim);
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all 0.15s;
}
.mobile-replace-btn.active {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

.mobile-more-btn {
  width: 42px;
  height: 42px;
  border: 1px solid var(--border-light);
  border-radius: 50%;
  background: var(--panel-2);
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all 0.15s;
}
.mobile-more-btn:hover {
  background: var(--panel-3);
  border-color: var(--accent);
}

/* Mobile modal */
.mobile-modal {
  position: fixed;
  inset: 0;
  z-index: 500;
  background: rgba(0,0,0,0.65);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  transition: opacity 0.25s;
}
.mobile-modal.hidden {
  opacity: 0;
  pointer-events: none;
}
.mobile-modal-content {
  width: 100%;
  max-width: 500px;
  max-height: 70vh;
  background: var(--panel-solid);
  border-radius: 20px 20px 0 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transform: translateY(0);
  transition: transform 0.3s;
}
/* Drag handle */
.mobile-modal-content::before {
  content: '';
  display: block;
  width: 40px;
  height: 4px;
  background: rgba(255,255,255,0.2);
  border-radius: 2px;
  margin: 10px auto 0;
}
.mobile-modal.hidden .mobile-modal-content {
  transform: translateY(100%);
}
.mobile-modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 22px 18px;
  border-bottom: 1px solid var(--border);
}
.mobile-modal-header h3 {
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.02em;
}
.mobile-modal-close {
  width: 34px;
  height: 34px;
  border: none;
  border-radius: 50%;
  background: var(--panel-2);
  color: var(--text);
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}
.mobile-modal-close:hover {
  background: var(--danger);
}
#mobileModalCategories {
  flex: 1;
  overflow-y: auto;
  padding: 12px 16px 24px;
}
#mobileModalCategories .elem-grid {
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

/* ---- Tooltip ---- */
.elem-tooltip {
  position: fixed;
  z-index: 999;
  background: rgba(14, 18, 30, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-light);
  border-left: 3px solid var(--tt-color, var(--accent));
  border-radius: var(--radius);
  padding: 12px 16px;
  max-width: 240px;
  box-shadow: 0 12px 40px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.04);
  pointer-events: none;
  opacity: 0;
  transform: translateY(4px) scale(0.96);
  transition: opacity 0.15s, transform 0.15s;
}
.elem-tooltip.visible {
  opacity: 1;
  transform: translateY(0) scale(1);
}
.elem-tooltip-name {
  font-weight: 700;
  font-size: 13px;
  margin-bottom: 4px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.elem-tooltip-desc {
  font-size: 11px;
  color: var(--text-dim);
  line-height: 1.5;
}
.elem-tooltip-props {
  margin-top: 8px;
  font-size: 10px;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}
.elem-tooltip-props span {
  background: linear-gradient(135deg, var(--panel-2), var(--panel-3));
  padding: 2px 8px;
  border-radius: 4px;
  border: 1px solid var(--border-light);
  font-weight: 600;
}

/* ---- Brush preview ---- */
#brushPreview {
  position: fixed;
  pointer-events: none;
  z-index: 200;
  border: 1.5px solid rgba(247, 168, 40, 0.5);
  border-radius: 50%;
  box-shadow: 0 0 12px rgba(247, 168, 40, 0.15);
  transition: width 0.1s, height 0.1s;
}

/* ---- Game Modals (Save/Load) ---- */
.game-modal {
  position: fixed;
  inset: 0;
  z-index: 9000;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.25s;
}
.game-modal.hidden {
  opacity: 0;
  pointer-events: none;
}
.game-modal-content {
  background: var(--panel-solid);
  border: 1px solid var(--border-light);
  border-radius: 16px;
  padding: 24px 28px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.6);
  width: 90%;
}
.game-modal-content h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}
.modal-btn {
  padding: 8px 18px;
  border: 1px solid var(--border-light);
  border-radius: 8px;
  background: var(--panel-2);
  color: var(--text-dim);
  font-size: 12px;
  cursor: pointer;
  font-family: Poppins, sans-serif;
  transition: all 0.15s;
}
.modal-btn:hover {
  background: var(--panel-3);
  color: var(--text);
}
.modal-btn-primary {
  background: linear-gradient(135deg, var(--accent), #e08a10);
  color: #0a0a0a;
  border-color: transparent;
  font-weight: 700;
}
.modal-btn-primary:hover {
  transform: scale(1.03);
  box-shadow: 0 2px 12px var(--accent-glow);
}
.save-card {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px;
  cursor: pointer;
  transition: all 0.15s;
}
.save-card:hover {
  border-color: var(--accent);
  background: var(--panel-2);
}
.save-card img {
  width: 100%;
  border-radius: 6px;
  image-rendering: pixelated;
  margin-bottom: 6px;
}
.save-card .save-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.save-card .save-date {
  font-size: 10px;
  color: var(--muted);
}
.save-card {
  position: relative;
}
.save-card .save-delete {
  float: right;
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 14px;
  padding: 2px;
}
.save-menu-btn {
  position: absolute;
  top: 6px;
  left: 6px;
  background: rgba(255,255,255,0.08);
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  font-size: 16px;
  padding: 1px 6px;
  border-radius: 4px;
  line-height: 1;
  letter-spacing: 1px;
}
.save-menu-btn:hover { background: rgba(255,255,255,0.15); color: var(--text); }
.save-menu {
  position: absolute;
  top: 28px;
  left: 6px;
  background: var(--panel-solid);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 4px 0;
  z-index: 10;
  min-width: 150px;
  box-shadow: var(--shadow);
}
.save-menu.hidden { display: none; }
.save-menu-item {
  display: block;
  width: 100%;
  background: none;
  border: none;
  color: var(--text-dim);
  font-size: 12px;
  font-family: 'Poppins', sans-serif;
  padding: 8px 14px;
  cursor: pointer;
  text-align: left;
}
.save-menu-item:hover { background: rgba(255,255,255,0.06); color: var(--text); }
.save-menu-delete:hover { color: var(--danger); }

/* ============================================
   RESPONSIVE DESIGN — 7 Breakpoint Tiers
   ============================================ */

/* ---- Ultra-wide / 4K (2561px+) ---- */
@media (min-width: 2561px) {
  #sidebar {
    width: 340px;
    min-width: 340px;
  }
  #sidebar.collapsed {
    margin-left: -340px;
  }
  .elem-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
  }
  .elem-swatch {
    width: 42px;
    height: 42px;
  }
  img.elem-icon {
    width: 30px;
    height: 30px;
  }
  .elem-name {
    font-size: 10px;
  }
  #toolbar {
    height: 56px;
    min-height: 56px;
  }
  .tool-btn {
    width: 42px;
    height: 42px;
    font-size: 18px;
  }
  .sel-swatch {
    width: 22px;
    height: 22px;
  }
  .sel-name {
    font-size: 13px;
  }
  .sidebar-header h2 {
    font-size: 15px;
  }
  .sidebar-footer {
    font-size: 12px;
    padding: 12px 18px;
  }
  .elem-tooltip {
    max-width: 300px;
    padding: 16px 20px;
  }
  .elem-tooltip-name {
    font-size: 15px;
  }
  .elem-tooltip-desc {
    font-size: 12px;
  }
}

/* ---- Large desktop (1441–2560px) ---- */
@media (min-width: 1441px) and (max-width: 2560px) {
  #sidebar {
    width: 280px;
    min-width: 280px;
  }
  #sidebar.collapsed {
    margin-left: -280px;
  }
  .elem-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
  }
  .elem-swatch {
    width: 38px;
    height: 38px;
  }
  img.elem-icon {
    width: 28px;
    height: 28px;
  }
  .elem-name {
    font-size: 10px;
  }
  .sidebar-footer {
    padding: 12px 16px;
  }
}

/* ---- Tablet portrait (701–900px) ---- */
@media (min-width: 701px) and (max-width: 900px) {
  #sidebar {
    width: 170px;
    min-width: 170px;
  }
  #sidebar.collapsed {
    margin-left: -170px;
  }
  .elem-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 4px;
  }
  .elem-swatch {
    width: 30px;
    height: 30px;
  }
  img.elem-icon {
    width: 22px;
    height: 22px;
  }
  .elem-btn {
    padding: 6px 3px 5px;
  }
  .sidebar-header {
    padding: 12px 12px 8px;
  }
  .sidebar-header h2 {
    font-size: 12px;
  }
  .sidebar-footer {
    padding: 8px 10px;
    font-size: 10px;
  }
  .elem-category-header {
    font-size: 9px;
    padding: 5px 6px;
  }
  #elementCategories {
    padding: 4px 6px;
  }
}

/* ---- Mobile (≤700px) ---- */
@media (max-width: 700px) {
  #sidebar {
    display: none !important;
  }
  #mobileBar {
    display: flex;
    padding-bottom: calc(4px + var(--sai-bottom));
  }
  #toolbar {
    padding: 0 8px;
    height: 46px;
    min-height: 46px;
  }
  .toolbar-title {
    display: none;
  }
  .toolbar-center {
    max-width: 180px;
  }
  .brush-slider {
    width: 80px;
  }
  .fps-counter {
    display: none;
  }
}

/* ---- Small phones (321–420px) ---- */
@media (max-width: 420px) {
  #toolbar {
    padding: 0 4px;
    gap: 2px;
  }
  .tool-btn {
    width: 34px;
    height: 34px;
    font-size: 14px;
  }
  .brush-slider {
    width: 60px;
  }
  .selected-elem-indicator {
    padding: 3px 8px 3px 4px;
    gap: 5px;
  }
  .sel-name {
    font-size: 10px;
  }
  .sel-swatch {
    width: 14px;
    height: 14px;
  }
  #mobileModalCategories .elem-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ---- Galaxy Fold / ultra-narrow (≤320px) ---- */
@media (max-width: 320px) {
  #toolbar {
    padding: 0 3px;
    gap: 1px;
    height: 42px;
    min-height: 42px;
  }
  .tool-btn {
    width: 30px;
    height: 30px;
    font-size: 13px;
  }
  .tool-sep {
    display: none;
  }
  .toolbar-home {
    width: 30px;
    height: 30px;
    font-size: 14px;
  }
  /* Hide non-essential toolbar buttons */
  #btnHeatmap,
  .speed-label {
    display: none;
  }
  .brush-slider {
    width: 45px;
  }
  .brush-label svg {
    display: none;
  }
  .brush-val {
    font-size: 10px;
    min-width: 14px;
  }
  .selected-elem-indicator {
    padding: 2px 6px 2px 3px;
    gap: 4px;
  }
  .sel-swatch {
    width: 12px;
    height: 12px;
  }
  .sel-name {
    font-size: 9px;
  }
  .toolbar-center {
    max-width: 120px;
  }
  /* Mobile bar */
  .mobile-elem-btn {
    padding: 5px 8px;
    font-size: 11px;
    gap: 4px;
  }
  .mobile-elem-swatch {
    width: 14px;
    height: 14px;
  }
  .mobile-replace-btn,
  .mobile-more-btn {
    width: 36px;
    height: 36px;
    font-size: 16px;
  }
  #mobileBar {
    height: 50px;
    min-height: 50px;
    gap: 2px;
  }
  /* Modal */
  #mobileModalCategories .elem-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 4px;
  }
  .mobile-modal-header {
    padding: 12px 16px;
  }
  .mobile-modal-header h3 {
    font-size: 14px;
  }
  .elem-name {
    font-size: 8px;
  }
}

/* ---- Landscape mobile ---- */
@media (max-height: 500px) and (orientation: landscape) {
  #toolbar {
    height: 38px;
    min-height: 38px;
  }
  .tool-btn {
    width: 30px;
    height: 30px;
  }
  #mobileBar {
    height: 40px;
    min-height: 40px;
    padding-bottom: calc(2px + var(--sai-bottom));
  }
  .mobile-elem-btn {
    padding: 4px 10px;
    font-size: 11px;
    min-height: 34px;
  }
  .mobile-elem-swatch {
    width: 14px;
    height: 14px;
  }
  .mobile-replace-btn,
  .mobile-more-btn {
    width: 34px;
    height: 34px;
  }
}

/* ---- Touch devices (global) ---- */
@media (hover: none) and (pointer: coarse) {
  .tool-btn {
    min-width: 44px;
    min-height: 44px;
  }
  .mobile-elem-btn {
    min-height: 44px;
  }
  .mobile-modal-close {
    width: 44px;
    height: 44px;
  }
  .sidebar-toggle {
    min-width: 44px;
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  .elem-btn {
    min-height: 54px;
  }
  /* Hide brush preview on touch — finger covers it anyway */
  #brushPreview {
    display: none !important;
  }
}

/* ---- Intro overlay ---- */
#introOverlay {
  position: fixed; inset: 0; z-index: 99997;
  background: rgba(8, 9, 15, 0.88);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  display: flex; align-items: center; justify-content: center;
  transition: opacity 0.4s ease;
}
.intro-card {
  text-align: center;
  padding: 48px 40px 40px;
  max-width: 380px;
  animation: introIn 0.5s ease-out;
}
.intro-logo {
  font-size: 32px; font-weight: 700;
  letter-spacing: 0.1em;
  background: linear-gradient(135deg, #e8eaf0 30%, #f7a828);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  margin-bottom: 8px;
}
.intro-sub {
  color: var(--muted); font-size: 14px; margin-bottom: 32px;
}
.intro-hints {
  display: flex; flex-direction: column; gap: 10px; margin-bottom: 36px;
}
.intro-hints span {
  color: var(--text-dim); font-size: 13px;
  padding: 10px 20px;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.intro-btn {
  padding: 12px 36px;
  background: linear-gradient(135deg, #f7a828, #e8901a);
  border: none; border-radius: 24px;
  color: #0e121e; font-family: 'Poppins', sans-serif;
  font-size: 15px; font-weight: 700;
  cursor: pointer; letter-spacing: 0.03em;
  transition: transform 0.15s, box-shadow 0.15s;
  box-shadow: 0 4px 20px rgba(247, 168, 40, 0.3);
}
.intro-btn:hover {
  transform: scale(1.04);
  box-shadow: 0 6px 28px rgba(247, 168, 40, 0.45);
}
@keyframes introIn {
  from { opacity: 0; transform: translateY(16px) scale(0.97); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

/* ---- Reduced motion ---- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}