.year-img { max-height: 180px; object-fit: cover; }
.coin-img { max-height: 220px; object-fit: contain; background: #fff; }
.back-to-top {
  position: fixed;
  bottom: 20px;
  right: 16px;
  z-index: 1000;
  display: none;
  border-radius: 50%;
  width: 48px;
  height: 48px;
  padding: 0;
  font-size: 20px;
}