/* Shared cover finishes and preserved comparison experiments. */
.sv-book[data-variant] {
  --ornament-ink: color-mix(in srgb, var(--cover), #754127 58%);
  --pattern-ink: color-mix(in srgb, var(--cover), #765239 27%);
  --binding-gold: color-mix(in srgb, var(--cover), #a37532 44%);
}
.sv-book[data-variant]::before { z-index: 0; }
.sv-book[data-variant]::after { z-index: 1; }
.sv-book[data-variant] .sv-book__frame { z-index: 2; }
.sv-book[data-variant] .sv-book__content { z-index: 3; }
.sv-book[data-variant] .sv-book__decoration {
  position: absolute;
  z-index: 1;
  inset: 0;
  border-radius: inherit;
  pointer-events: none;
  color: var(--ornament-ink);
}
.sv-book[data-variant] .sv-cover-pattern {
  position: absolute;
  inset: 3% 4% 3% 12%;
  border-radius: 3%;
  -webkit-mask-image: linear-gradient(to bottom, #000 0%, #000 18%, #0007 26%, transparent 37%, transparent 72%, #0007 81%, #000 90%, #000 100%);
  mask-image: linear-gradient(to bottom, #000 0%, #000 18%, #0007 26%, transparent 37%, transparent 72%, #0007 81%, #000 90%, #000 100%);
}
.sv-book[data-variant] .sv-cover-pattern--check {
  --check-band: color-mix(in srgb, var(--pattern-ink) 58%, transparent);
  background-image:
    repeating-linear-gradient(90deg, transparent 0 7cqw, var(--check-band) 7cqw 12cqw, transparent 12cqw 19cqw),
    repeating-linear-gradient(0deg, transparent 0 7cqw, var(--check-band) 7cqw 12cqw, transparent 12cqw 19cqw);
  opacity: .72;
}
.sv-book[data-variant] .sv-cover-pattern--diamond {
  background-image:
    repeating-linear-gradient(45deg, transparent 0, transparent calc(11cqw - 1px), var(--pattern-ink) calc(11cqw - 1px), var(--pattern-ink) 11cqw),
    repeating-linear-gradient(-45deg, transparent 0, transparent calc(11cqw - 1px), var(--pattern-ink) calc(11cqw - 1px), var(--pattern-ink) 11cqw);
}
.sv-book[data-variant] .sv-cover-pattern--pinstripe {
  background-image: repeating-linear-gradient(90deg, transparent 0, transparent calc(5cqw - 1px), var(--pattern-ink) calc(5cqw - 1px), var(--pattern-ink) 5cqw);
  opacity: .84;
}
.sv-book[data-variant] .sv-ornament {
  position: absolute;
  left: 15%;
  right: 8%;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.sv-book[data-variant] .sv-ornament--crest { top: 10.5%; }
.sv-book[data-variant] .sv-ornament--crest svg { display: block; width: 19cqw; height: 14cqw; }
.sv-book[data-variant] .sv-ornament--crest > span {
  margin-top: .6cqw;
  font-size: 3.8cqw;
  font-weight: 650;
  line-height: 1.4;
  letter-spacing: .21em;
}
.sv-book[data-variant] .sv-ornament--motif { top: 12%; }
.sv-book[data-variant] .sv-ornament--motif svg { display: block; width: 36cqw; height: 21cqw; }
.sv-book[data-variant] .sv-binding {
  position: absolute;
  inset: 0;
  border-radius: inherit;
}
.sv-book[data-variant] .sv-binding__spine {
  position: absolute;
  inset: 0 auto 0 0;
  width: 8%;
  border-radius: 40% 0 0 40% / 4% 0 0 4%;
  background: linear-gradient(90deg, #60351d80, transparent 60%, #673d2670);
  box-shadow: inset 1px 0 0 #fff6, 1px 0 1px #673d2640;
}
.sv-book[data-variant='binding']::before,
.sv-book[data-variant='signature-original']::before {
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--cover), #673d26 32%),
    color-mix(in srgb, var(--cover), #b07448 12%) 50%,
    color-mix(in srgb, var(--cover), #673d26 42%));
}
.sv-book[data-variant] .sv-binding__band {
  position: absolute;
  z-index: 4;
  left: 1%;
  width: 6%;
  height: .7cqw;
  border-top: 1px solid #ffebb378;
  border-bottom: 1px solid #744c2540;
  background: var(--binding-gold);
  box-shadow: 0 1px 1px #683d2638;
}
.sv-book[data-variant] .sv-binding__band--top { top: 16%; }
.sv-book[data-variant] .sv-binding__band--bottom { bottom: 16%; }
.sv-book[data-variant] .sv-binding__rule {
  position: absolute;
  left: 19%;
  right: 11%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--binding-gold) 15%, var(--binding-gold) 85%, transparent);
  box-shadow: 0 1px 0 #fff7;
}
.sv-book[data-variant] .sv-binding__rule--top { top: 8%; }
.sv-book[data-variant] .sv-binding__rule--bottom { bottom: 12%; }
.sv-book[data-variant] .sv-binding__volume {
  position: absolute;
  left: 15%;
  right: 8%;
  bottom: 7%;
  text-align: center;
  font-size: 3.8cqw;
  line-height: 1.4;
  font-weight: 650;
  letter-spacing: .22em;
}
.sv-book[data-variant='signature-original'] .sv-cover-pattern--diamond {
  --pattern-ink: color-mix(in srgb, var(--cover), #765239 20%);
  -webkit-mask-image: linear-gradient(to bottom, #0007 0%, transparent 9%, transparent 27%, #0006 32%, transparent 40%, transparent 73%, #0008 83%, #0008 100%);
  mask-image: linear-gradient(to bottom, #0007 0%, transparent 9%, transparent 27%, #0006 32%, transparent 40%, transparent 73%, #0008 83%, #0008 100%);
}
/* Revised collection: a plain face with a spine in the cover's color family. */
.sv-book[data-variant='signature'] {
  --ornament-ink: color-mix(in srgb, var(--spine, color-mix(in srgb, var(--cover), #202020 40%)), var(--cover) 12%);
}
.sv-book[data-variant='signature']::before {
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--spine, color-mix(in srgb, var(--cover), #202020 40%)), #000 15%),
    var(--spine, color-mix(in srgb, var(--cover), #202020 40%)) 55%,
    color-mix(in srgb, var(--spine, color-mix(in srgb, var(--cover), #202020 40%)), #000 19%));
  border-right-color: #fff8;
  box-shadow: inset 1px 1px 2px #fff7, 1px 0 2px #0003;
  filter: none;
}
.sv-book[data-variant='signature'] .sv-binding__spine {
  background: linear-gradient(90deg, #0002, #fff1 45%, #0003);
  box-shadow: inset 1px 0 0 #fff5, 1px 0 1px #0003;
}
.sv-book[data-variant='signature'] .sv-binding__band { box-shadow: 0 1px 1px #0002; }

/* Two-color finish study. The supplied tokens keep every detail in its palette. */
.sv-book[data-variant='signature-detail'] {
  --ornament-ink: var(--book-ornament, color-mix(in srgb, var(--spine, var(--cover)), #202020 20%));
  --binding-gold: var(--book-foil, color-mix(in srgb, var(--cover), #a37532 44%));
}
.sv-book[data-variant='signature-detail']::before {
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--spine, color-mix(in srgb, var(--cover), #202020 40%)), #000 11%),
    color-mix(in srgb, var(--spine, color-mix(in srgb, var(--cover), #202020 40%)), #fff 6%) 36%,
    var(--spine, color-mix(in srgb, var(--cover), #202020 40%)) 62%,
    color-mix(in srgb, var(--spine, color-mix(in srgb, var(--cover), #202020 40%)), #000 13%));
  border-right-color: color-mix(in srgb, var(--book-seam-shadow, #0003), var(--cover) 35%);
  box-shadow: inset 1px 1px 1px #ffffff57, 1px 0 1px #00000019;
  filter: none;
}
.sv-book[data-variant='signature-detail']::after {
  box-shadow:
    inset 1px 0 1px color-mix(in srgb, var(--book-seam-light, #fff7), transparent 32%),
    inset -1px -1px 2px #00000013;
}
.sv-book[data-variant='signature-detail'] .sv-binding__spine {
  background: linear-gradient(90deg, #00000009, #ffffff07 45%, #00000010);
  box-shadow: inset 1px 0 0 #ffffff36, 1px 0 1px #00000014;
}
.sv-book[data-variant='signature-detail'] .sv-binding__seam {
  position: absolute;
  left: 8%;
  top: 2%;
  bottom: 2%;
  width: .7cqw;
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--book-seam-shadow, #0003), var(--cover) 25%),
    color-mix(in srgb, var(--book-seam-shadow, #0003), var(--cover) 25%) 28%,
    color-mix(in srgb, var(--cover), var(--book-seam-shadow, #0003) 22%) 58%,
    color-mix(in srgb, var(--book-seam-light, #fff7), var(--cover) 24%) 84%,
    var(--cover));
  border-radius: 40% / 2%;
}
.sv-book[data-variant='signature-detail'] .sv-book__title { color: var(--ink); }
.sv-book[data-variant='signature-detail'] .sv-book__subtitle {
  color: var(--book-subtitle, var(--ink));
}
.sv-book[data-variant='signature-detail'] .sv-book__rule {
  background: linear-gradient(90deg, transparent, var(--book-foil, var(--binding-gold)), transparent);
  opacity: .7;
}
.sv-book[data-variant='signature-detail'] .sv-book__frame {
  stroke: color-mix(in srgb, var(--book-frame-shadow, color-mix(in srgb, var(--cover), #202020 28%)), var(--cover) 22%);
  stroke-width: 1.2;
  filter: drop-shadow(.4px .6px 0 var(--book-frame-light, #fff8));
}
.sv-book[data-variant='signature-detail'] .sv-ornament--wordmark,
.sv-book[data-variant='signature-detail'] .sv-binding__volume {
  color: var(--book-ornament, var(--ornament-ink));
}
.sv-book[data-variant='signature-detail'] .sv-ornament--wordmark { top: 14%; }
.sv-book[data-variant='signature-detail'] .sv-ornament--wordmark > span {
  font-size: 4.1cqw;
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: .18em;
}
.sv-book[data-variant='signature-detail'] .sv-binding__band {
  border-top-color: color-mix(in srgb, var(--book-foil, var(--binding-gold)), var(--book-frame-light, #fff) 60%);
  border-bottom-color: color-mix(in srgb, var(--book-foil, var(--binding-gold)), #000 20%);
  box-shadow: 0 1px 1px #00000014;
  opacity: .75;
}
.sv-book[data-variant='signature-detail'] .sv-binding__rule {
  background: linear-gradient(90deg, transparent, var(--book-foil, var(--binding-gold)) 15%, var(--book-foil, var(--binding-gold)) 85%, transparent);
  box-shadow: 0 .5px 0 color-mix(in srgb, var(--book-frame-light, #fff7), transparent 30%);
}