.stack-filler {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 46vh;
  padding: 2rem 1.5rem;
  text-align: center;
  color: var(--cl-base);
  font-size: 0.9rem;
}
.stack-filler p { max-width: 26em; margin: 0; }

.stack-gallery {
  position: relative;
  width: min(760px, 92%);
  margin: 0 auto;
  height: 220vh;
}

.stack-sticky {
  position: sticky;
  top: 100px;
  height: clamp(320px, 52vh, 440px);
}

.stack-card {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 20px;
  padding: 2.5rem;
  text-align: center;
  color: #fff;
  box-shadow: 0 24px 60px rgba(49,33,20,0.22);
  opacity: var(--stack-opacity, 1);
  transform: translate3d(0, var(--stack-y, 0%), 0);
  transition: transform 700ms cubic-bezier(0.16,1,0.3,1), opacity 500ms ease;
}
.stack-card h3 { margin: 0 0 0.7rem; font-size: 1.15rem; }
.stack-card p { margin: 0; font-size: 0.86rem; line-height: 1.8; max-width: 26em; opacity: 0.92; }

/* 写真＋文字が読める濃さの覆い。写真読込前のフォールバックとしてグラデーションを残す */
.stack-card-photo {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.stack-card::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(35,20,9,0.45) 0%, rgba(35,20,9,0.62) 100%);
}
.stack-card-body {
  position: relative;
  z-index: 1;
  text-shadow: 0 1px 8px rgba(0,0,0,0.35);
}

.stack-card:nth-child(1) { z-index: 1; background: linear-gradient(135deg,#cd853f,#4d4136); }
.stack-card:nth-child(2) { z-index: 2; background: linear-gradient(135deg,#f08f00,#312114); }
.stack-card:nth-child(3) { z-index: 3; background: linear-gradient(135deg,#D35400,#4d4136); }