/* The front, mapped spine and page block form one closed book. */
.rm-cover-mockup {
  --rm-cover-depth: 28.8px;
  --rm-cover-paper: #fffaf0;
  position: relative;
  isolation: auto;
  overflow: visible;
  transform: perspective(1440px) rotateY(18deg) rotateX(1deg);
  transform-origin: center center;
  transform-style: preserve-3d;
}

.cs-detail-art.rm-cover-mockup { --rm-cover-depth: 57.6px; width:80%; justify-self:center; }
.rmops-cover-drawer-art.rm-cover-mockup { width:min(128px,80%); }

/* Back board supplies the book's actual depth and its cast shadow. */
.rm-cover-mockup::before {
  position: absolute;
  inset: 0;
  border-radius: 2px;
  background: #383127;
  box-shadow: -5px 14px 22px rgba(25,20,32,.22), 0 2px 5px rgba(25,20,32,.12);
  content: "";
  transform: translateZ(calc(-1 * var(--rm-cover-depth)));
}

/* A separate perpendicular face, with artwork from the current front cover. */
.rm-cover-mockup-spine {
  position: absolute;
  top: 0;
  bottom: 0;
  left: calc(-1 * var(--rm-cover-depth));
  width: var(--rm-cover-depth);
  overflow: hidden;
  border-radius: 2px 0 0 2px;
  background: #383127;
  transform-origin: right center;
  transform: rotateY(-90deg);
  backface-visibility: hidden;
  pointer-events: none;
}
.rm-cover-mockup-spine > img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: none;
  aspect-ratio: auto;
  border-radius: 0;
  object-fit: cover;
  object-position: left center;
  /* Only the outer artwork edge wraps around the binding, avoiding cut titles. */
  transform: scaleX(4);
  transform-origin: left center;
}
.rm-cover-mockup-spine::after {
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg,rgba(0,0,0,.48),rgba(0,0,0,.12) 38%,transparent 65%,rgba(255,255,255,.12) 88%,rgba(0,0,0,.3));
  box-shadow: inset 1px 0 rgba(255,255,255,.18), inset -1px 0 rgba(0,0,0,.24);
  content: "";
}

/* The narrow bottom page block meets the spine and both boards. */
.rm-cover-mockup::after {
  position: absolute;
  top: calc(100% - 2px);
  left: 2px;
  width: calc(100% - 4px);
  height: calc(var(--rm-cover-depth) - 2px);
  border: 1px solid rgba(56,49,39,.18);
  box-sizing: border-box;
  background: repeating-linear-gradient(0deg,#e5dfd2 0 1px,var(--rm-cover-paper) 1px 3px);
  content: "";
  transform-origin: top center;
  transform: rotateX(-90deg);
  backface-visibility: hidden;
}

.rm-cover-mockup > img {
  position: relative;
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 2 / 3;
  border-radius: 1px 2px 2px 1px;
  object-fit: cover;
  backface-visibility: hidden;
  box-shadow: -1px 0 1px rgba(0,0,0,.2),1px 0 1px rgba(0,0,0,.12);
  transform: translateZ(.8px);
}

[data-theme="dark"] .rm-cover-mockup::before {
  box-shadow: -5px 14px 24px rgba(0,0,0,.42),0 2px 5px rgba(0,0,0,.25);
}
@media(max-width:580px) {
  .cs-detail-art.rm-cover-mockup {
    --rm-cover-depth: 33.6px;
    width:min(144px,calc(25.6vh * 2 / 3));
    width:min(144px,calc(25.6dvh * 2 / 3));
  }
}