* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

body {
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  position: fixed;
  top: 0;
  left: 0;
  background: #e8e8e8;
  user-select: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  touch-action: none;
}

html {
  height: 100%;
}

#gameCanvas {
  display: block;
  width: 100vw;
  height: 100vh;
  cursor: pointer;
}

/* Home overlay */
.home-overlay {
  position: fixed;
  inset: 0;
  background: radial-gradient(
    circle at 30% 30%,
    rgba(255, 255, 255, 0.7),
    rgba(232, 232, 232, 0.9)
  );
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
}

.home-card {
  text-align: center;
  color: #7a7a7a;
  padding: 24px;
  gap: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.home-title {
  font-size: 48px;
  letter-spacing: 2px;
  font-weight: 400;
}

.home-subtitle {
  font-size: 24px;
  margin-top: 8px;
}

.home-hint {
  font-size: 16px;
  color: #9a9a9a;
  margin-top: 6px;
}

.home-btn {
  margin-top: 16px;
  padding: 10px 28px;
  font-size: 18px;
  border: none;
  border-radius: 20px;
  background: #7a7a7a;
  color: #fff;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.12);
  transition: transform 0.15s ease, opacity 0.2s ease;
}

.home-btn:active {
  transform: scale(0.97);
  opacity: 0.9;
}

/* UI Buttons */
.ui-btn {
  position: absolute;
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.8);
  cursor: pointer;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.ui-btn:hover {
  background: rgba(255, 255, 255, 0.95);
  transform: scale(1.1);
}

.ui-btn:active {
  transform: scale(0.95);
}

.close-btn {
  top: 10px;
  left: 10px;
}

.close-btn::before {
  content: "";
  width: 20px;
  height: 20px;
  background: #666;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z'/%3E%3C/svg%3E")
    no-repeat center;
  mask-size: contain;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z'/%3E%3C/svg%3E")
    no-repeat center;
  -webkit-mask-size: contain;
}

/* Sound toggle UI (icon replaces here) */
/* 音效开关按钮：替换 mask 为自定义声音图标 */
.sound-btn {
  top: 10px;
  right: 10px;
}

/* 音效开关图标区域：替换 mask 数据URI 即可更换图标 */
.sound-btn::before {
  content: "";
  width: 20px;
  height: 20px;
  background: #666;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M3 9v6h4l5 5V4L7 9H3zm13.5 3c0-1.77-1.02-3.29-2.5-4.03v8.05c1.48-.73 2.5-2.25 2.5-4.02zM14 3.23v2.06c2.89.86 5 3.54 5 6.71s-2.11 5.85-5 6.71v2.06c4.01-.91 7-4.49 7-8.77s-2.99-7.86-7-8.77z'/%3E%3C/svg%3E")
    no-repeat center;
  mask-size: contain;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M3 9v6h4l5 5V4L7 9H3zm13.5 3c0-1.77-1.02-3.29-2.5-4.03v8.05c1.48-.73 2.5-2.25 2.5-4.02zM14 3.23v2.06c2.89.86 5 3.54 5 6.71s-2.11 5.85-5 6.71v2.06c4.01-.91 7-4.49 7-8.77s-2.99-7.86-7-8.77z'/%3E%3C/svg%3E")
    no-repeat center;
  -webkit-mask-size: contain;
}

/* 静音态图标：替换 mask 数据URI 即可更换图标 */
.sound-btn.muted::before {
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M16.5 12c0-1.77-1.02-3.29-2.5-4.03v2.21l2.45 2.45c.03-.2.05-.41.05-.63zm2.5 0c0 .94-.2 1.82-.54 2.64l1.51 1.51C20.63 14.91 21 13.5 21 12c0-4.28-2.99-7.86-7-8.77v2.06c2.89.86 5 3.54 5 6.71zM4.27 3L3 4.27 7.73 9H3v6h4l5 5v-6.73l4.25 4.25c-.67.52-1.42.93-2.25 1.18v2.06c1.38-.31 2.63-.95 3.69-1.81L19.73 21 21 19.73l-9-9L4.27 3zM12 4L9.91 6.09 12 8.18V4z'/%3E%3C/svg%3E")
    no-repeat center;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M16.5 12c0-1.77-1.02-3.29-2.5-4.03v2.21l2.45 2.45c.03-.2.05-.41.05-.63zm2.5 0c0 .94-.2 1.82-.54 2.64l1.51 1.51C20.63 14.91 21 13.5 21 12c0-4.28-2.99-7.86-7-8.77v2.06c2.89.86 5 3.54 5 6.71zM4.27 3L3 4.27 7.73 9H3v6h4l5 5v-6.73l4.25 4.25c-.67.52-1.42.93-2.25 1.18v2.06c1.38-.31 2.63-.95 3.69-1.81L19.73 21 21 19.73l-9-9L4.27 3zM12 4L9.91 6.09 12 8.18V4z'/%3E%3C/svg%3E")
    no-repeat center;
}

/* 音量滑块：可在此替换 thumb 造型以匹配音效UI */
.volume-slider {
  position: absolute;
  top: 60px;
  right: 10px;
  width: 8px;
  height: 120px;
  z-index: 100;
  -webkit-appearance: none;
  appearance: none;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 4px;
  outline: none;
  writing-mode: bt-lr;
  -webkit-appearance: slider-vertical;
}

.volume-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.9);
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.volume-slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.9);
  cursor: pointer;
  border: none;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

/* Rain Slider */
.rain-slider {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  width: 50px;
  height: 300px;
  z-index: 100;
}

.rain-slider-track {
  position: absolute;
  left: 50%;
  top: 0;
  transform: translateX(-50%);
  width: 4px;
  height: 100%;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 2px;
}

.rain-slider-handle {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.9);
  border-radius: 50%;
  cursor: grab;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  transition: transform 0.1s ease;
}

.rain-slider-handle:active {
  cursor: grabbing;
  transform: translate(-50%, -50%) scale(1.1);
}

.rain-slider-min-icon,
.rain-slider-max-icon {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
}

.rain-slider-min-icon {
  top: 0;
}

.rain-slider-max-icon {
  bottom: 0;
}

.rain-icon {
  pointer-events: none;
}

/* Hide UI when sound is off */
.volume-slider.hidden {
  opacity: 0;
  pointer-events: none;
}