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

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  overscroll-behavior: none;
  -webkit-overflow-scrolling: auto;
  touch-action: manipulation;
  -webkit-user-select: none;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
}

body {
  padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

#scene {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

#ui-layer {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 10;
}

#ui-layer > * {
  pointer-events: auto;
}

.float-btn {
  position: fixed;
  right: 16px;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  border: none;
  background: rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: #fff;
  font-size: 22px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.15s, background 0.15s;
  z-index: 20;
}

.float-btn:hover {
  transform: scale(1.1);
  background: rgba(0, 0, 0, 0.5);
}

.float-btn:active {
  transform: scale(0.9);
  background: rgba(0, 0, 0, 0.6);
}

#btn-customize {
  bottom: 92px;
}

#btn-sound {
  bottom: 24px;
}

/* Panel overlay */
#panel-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.3);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 30;
}

#panel-overlay:not(.hidden) {
  opacity: 1;
}

#panel-overlay.hidden {
  display: none;
}

/* Customize panel */
#customize-panel {
  position: fixed;
  top: 0;
  right: 0;
  width: 300px;
  max-width: 85vw;
  height: 100%;
  background: rgba(20, 20, 40, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-left: 1px solid rgba(255, 255, 255, 0.1);
  z-index: 40;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#customize-panel:not(.hidden) {
  transform: translateX(0);
}

#customize-panel.hidden {
  display: none;
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 20px 12px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  flex-shrink: 0;
}

.panel-header h2 {
  color: #fff;
  font-size: 16px;
  font-weight: 600;
}

.close-btn {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: none;
  background: rgba(255, 255, 255, 0.1);
  color: #ccc;
  font-size: 14px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

.close-btn:hover {
  background: rgba(255, 255, 255, 0.2);
}

.panel-body {
  flex: 1;
  overflow-y: auto;
  padding: 16px 20px 40px;
}

/* Option group */
.option-group {
  margin-bottom: 20px;
}

.option-label {
  color: rgba(255, 255, 255, 0.7);
  font-size: 12px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

.option-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

/* Color swatch */
.color-swatch {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.15s, border-color 0.15s;
  flex-shrink: 0;
}

.color-swatch:hover {
  transform: scale(1.15);
}

.color-swatch.selected {
  border-color: #fff;
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.3);
}

/* Style option */
.style-option {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  border: 2px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.05);
  color: #ccc;
  font-size: 13px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
  flex-shrink: 0;
}

.style-option:hover {
  border-color: rgba(255, 255, 255, 0.4);
  background: rgba(255, 255, 255, 0.1);
}

.style-option.selected {
  border-color: #fff;
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
}

/* Reset button */
.reset-btn {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.05);
  color: #ccc;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.15s;
  margin-top: 8px;
}

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

/* Scrollbar */
.panel-body::-webkit-scrollbar {
  width: 4px;
}

.panel-body::-webkit-scrollbar-track {
  background: transparent;
}

.panel-body::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 2px;
}