/* 点击脚印由透明折射底层和清晰的玻璃边缘组成，中心始终透出页面。 */
:root {
  --paw-glass-art: url("assets/icons/paw-glass-night.svg");
  --paw-glass-tint: rgb(153 212 255 / .035);
  --paw-glass-brightness: 1.2;
  --paw-glass-depth: drop-shadow(0 1px .7px rgb(0 5 20 / .42));
}
:root[data-theme="light"] {
  --paw-glass-art: url("assets/icons/paw-glass-day.svg");
  --paw-glass-tint: rgb(179 217 246 / .025);
  --paw-glass-brightness: .96;
  --paw-glass-depth: drop-shadow(0 1px .7px rgb(42 75 114 / .22));
}
.click-paw {
  width: 40px;
  height: 40px;
  filter: none;
  opacity: 1;
  animation: paw-glass-fade .8s linear forwards;
}
.click-paw::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--paw-glass-tint);
  -webkit-backdrop-filter: blur(1.1px) brightness(var(--paw-glass-brightness)) saturate(125%);
  backdrop-filter: blur(1.1px) brightness(var(--paw-glass-brightness)) saturate(125%);
  -webkit-mask: url("assets/icons/paw-four.svg") center / contain no-repeat;
  mask: url("assets/icons/paw-four.svg") center / contain no-repeat;
}
.click-paw::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--paw-glass-art) center / contain no-repeat;
  filter: var(--paw-glass-depth);
  pointer-events: none;
}
/* 高光不呼吸、不闪烁，保持半秒后只改变整体透明度。 */
@keyframes paw-glass-fade {
  0%, 62.5% { opacity: 1; scale: 1; }
  100% { opacity: 0; scale: 1; }
}
@media (prefers-reduced-motion: reduce) {
  .click-paw { display: none; animation: none; }
}