/* =============================================================================
   Chino's Blog — Snow effect (tippy.webp)
   -----------------------------------------------------------------------------
   全站背景飘雪：以 素材/chino/tippy.webp 作为雪花粒子。
   固定全屏层，pointer-events:none，位于内容之上、导航之下，
   由 main.js 注入粒子（随机大小 / 速度 / 水平漂移 / 旋转）。
   尊重 prefers-reduced-motion：直接隐藏。
   ============================================================================ */
.snow-layer {
  position: fixed;
  inset: 0;
  z-index: 0;                 /* 内容(静态,≈0) 之上、导航(z:20) 之下 */
  pointer-events: none;
  overflow: hidden;
}

.snowflake {
  position: absolute;
  top: -8%;
  background-image: url("/static/chino/tippy.webp");
  background-repeat: no-repeat;
  background-position: center;
  background-size: contain;
  opacity: var(--snow-opacity, .6);
  will-change: transform;
  animation-name: snow-fall;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}

@keyframes snow-fall {
  0%   { transform: translate3d(0, -12vh, 0) rotate(0deg); }
  100% { transform: translate3d(var(--drift, 0px), 112vh, 0) rotate(var(--spin, 360deg)); }
}

@media (prefers-reduced-motion: reduce) {
  .snow-layer { display: none !important; }
}