.product-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 2.5rem;
}

.product-list {
  display: block;
}

/* =========================
   プレビュー配置エリア
========================= */
.preview-area {
  border-left: 1px solid rgba(0,0,0,.08);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* =========================
   プレビュー本体
========================= */
.preview-popup {
  position: sticky;
  top: 50%;
  transform: translateY(-50%);
  width: 250px;
  aspect-ratio: 3 / 4;

  background: #f8fafc;      /* 真っ白やめる */
  box-shadow: none;         /* 影弱め or 消す */

  overflow: hidden;
  opacity: 1;
  pointer-events: none;
  background: none;
}

.preview-popup img {
  position: absolute;
  inset: 0;
  margin: auto;
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}




/* =========================
   ベース画像
========================= */
.preview-popup .base {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

/* =========================
   光（重ね画像）
========================= */
.preview-popup .glow {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;

  opacity: 0;
  transition: opacity .15s ease;
}

/* 光ON */
.preview-popup .glow.active {
  opacity: 1;
}

/* =========================
   レスポンシブ（SP）
========================= */
@media (max-width: 646px) {
  .product-layout {
    grid-template-columns: 1fr;
  }

  .preview-area {
    display: none;
  }
}