/* ====== 翻牌配对游戏 ====== */
.flip-card{
  aspect-ratio:1;cursor:pointer;
}
.flip-card-inner{
  width:100%;height:100%;position:relative;
  transform-style:preserve-3d;-webkit-transform-style:preserve-3d;
  transition:transform .4s ease;border-radius:12px;
}
.flip-card.flipped .flip-card-inner,
.flip-card.matched .flip-card-inner{
  transform:rotateY(180deg);-webkit-transform:rotateY(180deg);
}
.flip-card-front,.flip-card-back{
  position:absolute;width:100%;height:100%;border-radius:12px;
  display:flex;align-items:center;justify-content:center;
  backface-visibility:hidden;-webkit-backface-visibility:hidden;
}
.flip-card-front{
  background:linear-gradient(135deg,var(--blue),#5856D6);
  font-size:clamp(18px,4.5vw,30px);
  box-shadow:0 2px 8px rgba(0,0,0,.15);
}
.flip-card-back{
  background:var(--card);border:2px solid var(--gl);
  font-size:clamp(18px,4.5vw,30px);
  transform:rotateY(180deg);-webkit-transform:rotateY(180deg);
  box-shadow:0 2px 6px rgba(0,0,0,.08);
}
.flip-card.matched .flip-card-back{
  background:rgba(52,199,89,.1);border-color:var(--green);
}
.flip-card:not(.matched):active{transform:scale(.92)}