@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500&family=Noto+Serif+SC:wght@500;600&display=swap');

:root {
  --wall: #faf9f5;
  --ink: #1b1a18;
  --muted: #6e6b64;
  --faint: #a09b91;
  --rail-top: #e8e2d4;
  --rail-bot: #cfc7b6;
  --rail-shadow: rgba(60, 50, 30, 0.08);
  --line: #e6e3dc;
  --col: 740px;
  --hover-ring: rgba(27, 26, 24, 0.18);
  --hover-lift: 0 10px 22px rgba(40, 30, 20, 0.14);
  --pad: 24px;

  --t-expand: 250ms;
  --t-collapse: 230ms;
  --t-pull: 500ms;
  --t-flip: 1000ms;
  --t-settle: 580ms;
  --t-putback: 500ms;
  --t-land: 480ms;
  --t-veil: 580ms;
  --ease-motion: cubic-bezier(0.32, 0.72, 0, 1);
  --ease-out: var(--ease-motion);
  --ease-in: var(--ease-motion);
  --ease-inout: var(--ease-motion);
  --ease-pull: var(--ease-motion);
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--wall);
  color: var(--ink);
  font-family: "Noto Sans SC", "PingFang SC", sans-serif;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}
body.is-busy { cursor: wait; }
body.is-busy .shelf-view { pointer-events: none; }

#app { position: relative; min-height: 100vh; }

.page {
  width: min(100%, var(--col));
  margin: 0 auto;
  padding: 40px var(--pad) 56px;
}

.brand {
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.06em;
  margin-bottom: 24px;
}
h1 {
  margin: 0 0 10px;
  font-family: "Noto Serif SC", "Songti SC", serif;
  font-size: clamp(28px, 5vw, 36px);
  font-weight: 600;
}
.lede {
  margin: 0 0 20px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.qa-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 36px;
  padding: 10px 12px;
  background: rgba(255,255,255,0.45);
  border: 1px solid var(--line);
  border-radius: 6px;
}
.qa-label {
  font-size: 11px;
  color: var(--faint);
  letter-spacing: 0.08em;
  margin-right: 4px;
}
.qa-btn {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  font-size: 12px;
  padding: 5px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-family: inherit;
}
.qa-btn.is-active {
  background: var(--ink);
  color: var(--wall);
  border-color: var(--ink);
}
.qa-hint {
  font-size: 11px;
  color: var(--muted);
  margin-left: auto;
}

.bay { margin-bottom: 36px; }
.row-label {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
}
.row-label .name {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.12em;
}
.row-label .hint {
  font-size: 11px;
  color: var(--faint);
  letter-spacing: 0.04em;
}

.ledge { position: relative; padding-bottom: 10px; }
.rail {
  height: 7px;
  background: linear-gradient(180deg, var(--rail-top) 0%, var(--rail-bot) 100%);
  border-radius: 1px;
  box-shadow: 0 6px 14px var(--rail-shadow);
}

.covers {
  display: flex;
  align-items: flex-end;
  gap: 14px;
  min-height: 210px;
  padding-bottom: 2px;
  flex-wrap: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}
.covers::-webkit-scrollbar { display: none; }

.cover {
  width: 118px;
  height: 178px;
  border: none;
  padding: 0;
  display: block;
  cursor: pointer;
  border-radius: 2px 3px 0 0;
  background-color: #2a2a2a;
  background-size: cover;
  background-position: center top;
  background-repeat: no-repeat;
  box-shadow:
    inset -2px 0 0 rgba(0,0,0,0.12),
    inset 1px 0 0 rgba(255,255,255,0.08),
    0 6px 14px rgba(40, 30, 20, 0.08);
  transform: translateY(0) scale(1);
  transition: transform 0.18s ease, box-shadow 0.18s ease, opacity 0.2s ease;
  position: relative;
  overflow: hidden;
  flex-shrink: 0;
}
.cover:hover,
.cover:focus-visible {
  transform: translateY(-10px) scale(1.04);
  box-shadow:
    0 0 0 2px rgba(255,255,255,0.85),
    0 0 0 3px var(--hover-ring),
    var(--hover-lift);
  z-index: 2;
  outline: none;
}
.cover.is-placeholder {
  opacity: 0.22;
  filter: grayscale(0.15);
  pointer-events: none;
  box-shadow: none;
  transform: none !important;
}

.spines {
  display: flex;
  align-items: flex-end;
  gap: 4px;
  min-height: 188px;
  flex-wrap: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
}
.spines::-webkit-scrollbar { display: none; }

.spine {
  height: 150px;
  width: 28px;
  border: none;
  padding: 10px 0;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: "Noto Serif SC", serif;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: #F7F3EA;
  cursor: pointer;
  border-radius: 1px 2px 0 0;
  box-shadow:
    inset -1px 0 0 rgba(255,255,255,0.12),
    inset 1px 0 0 rgba(0,0,0,0.18);
  display: flex;
  align-items: center;
  justify-content: center;
  transform: translateY(0) scale(1);
  transition:
    transform 0.16s ease,
    box-shadow 0.16s ease,
    filter 0.16s ease,
    width var(--t-expand) var(--ease-out),
    height var(--t-expand) var(--ease-out),
    margin var(--t-expand) var(--ease-out),
    opacity 0.2s ease,
    background-size var(--t-expand) var(--ease-out);
  flex-shrink: 0;
  position: relative;
  overflow: hidden;
  background-size: cover;
  background-position: center top;
  background-repeat: no-repeat;
}
.spine.thin { width: 18px; font-size: 10px; height: 122px; color: #2A261E; }
.spine.light-text { color: #F7F3EA; }
.spine.dark-text { color: #1b1a18; }
.spine span { pointer-events: none; transition: opacity 120ms ease; }
.spine:hover,
.spine:focus-visible {
  transform: translateY(-8px) scale(1.06);
  box-shadow:
    0 0 0 2px rgba(255,255,255,0.9),
    0 0 0 3px var(--hover-ring),
    0 8px 16px rgba(40, 30, 20, 0.16);
  filter: brightness(1.08);
  z-index: 2;
  outline: none;
}
.spine.is-placeholder {
  opacity: 0.22;
  filter: grayscale(0.15);
  pointer-events: none;
  box-shadow: none;
  transform: none !important;
}
.spine.is-placeholder span { opacity: 0.55; }
.cover.is-placeholder.is-landing,
.spine.is-placeholder.is-landing {
  opacity: 0;
  transition: opacity 220ms var(--ease-motion);
}

/* Mode C: temporary expand on spine wall */
/* resting spines: solid hue only; cover image only when expanded */
.spine[class*="img-"] {
  background-image: none !important;
}
.spine.is-expanded[class*="img-"] {
  background-image: unset;
}
.spine.is-expanded.img-clean-code { background-image: url("covers/clean-code.jpg") !important; }
.spine.is-expanded.img-refactoring { background-image: url("covers/refactoring.jpg") !important; }
.spine.is-expanded.img-design-patterns { background-image: url("covers/design-patterns.jpg") !important; }
.spine.is-expanded.img-pragmatic-programmer { background-image: url("covers/pragmatic-programmer.jpg") !important; }
.spine.is-expanded.img-continuous-delivery { background-image: url("covers/continuous-delivery.jpg") !important; }
.spine.is-expanded.img-phoenix-project { background-image: url("covers/phoenix-project.jpg") !important; }
.spine.is-expanded.img-mythical-man-month { background-image: url("covers/mythical-man-month.jpg") !important; }
.spine.is-expanded.img-tdd { background-image: url("covers/tdd.jpg") !important; }
.spine.is-expanded.img-lean-startup { background-image: url("covers/lean-startup.jpg") !important; }
.spine.is-expanded.img-release-it { background-image: url("covers/release-it.jpg") !important; }
.spine.is-expanded.img-sre { background-image: url("covers/sre.jpg") !important; }
.spine.is-expanded.img-team-topologies { background-image: url("covers/team-topologies.jpg") !important; }
.spine.is-expanded.img-accelerate { background-image: url("covers/accelerate.jpg") !important; }
.spine.is-expanded.img-ddd { background-image: url("covers/ddd.jpg") !important; }
.spine.is-expanded.img-microservices { background-image: url("covers/microservices.jpg") !important; }
.spine.is-expanded.img-eaa { background-image: url("covers/eaa.jpg") !important; }
.spine.is-expanded.img-ddia { background-image: url("covers/ddia.jpg") !important; }
.spine.is-expanded.img-fundamentals-sa { background-image: url("covers/fundamentals-sa.jpg") !important; }
.spine.is-expanded.img-implementing-ddd { background-image: url("covers/implementing-ddd.jpg") !important; }
.spine.is-expanded.img-systems-performance { background-image: url("covers/systems-performance.jpg") !important; }
.spine.is-expanded.img-clean-architecture { background-image: url("covers/clean-architecture.jpg") !important; }

.spine.is-expanded {
  width: 100px;
  height: 152px;
  margin: 0 4px 0 2px;
  padding: 0;
  writing-mode: horizontal-tb;
  text-orientation: initial;
  letter-spacing: 0;
  transform: translateY(-10px) scale(1.03);
  box-shadow:
    inset -2px 0 0 rgba(0,0,0,0.14),
    0 0 0 2px rgba(255,255,255,0.9),
    0 0 0 3px var(--hover-ring),
    var(--hover-lift);
  filter: none;
  z-index: 3;
  transition:
    width var(--t-expand) var(--ease-out),
    height var(--t-expand) var(--ease-out),
    margin var(--t-expand) var(--ease-out),
    transform var(--t-expand) var(--ease-out),
    box-shadow var(--t-expand) var(--ease-out);
}
.spine.is-expanded span { opacity: 0; position: absolute; }
.spine.is-collapsing {
  transition:
    width var(--t-collapse) var(--ease-motion),
    height var(--t-collapse) var(--ease-motion),
    margin var(--t-collapse) var(--ease-motion),
    transform var(--t-collapse) var(--ease-motion),
    box-shadow var(--t-collapse) var(--ease-motion),
    background-size var(--t-collapse) var(--ease-motion);
}
/* C collapse: shrink while still "expanded" class — drop cover image to solid hue immediately, never flash a wide black plate */
.spine.is-expanded.is-collapsing {
  width: 28px;
  height: 150px;
  margin: 0;
  padding: 10px 0;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  letter-spacing: 0.16em;
  transform: translateY(0) scale(1);
  filter: none;
  box-shadow:
    inset -1px 0 0 rgba(255,255,255,0.12),
    inset 1px 0 0 rgba(0,0,0,0.18);
  background-image: none !important;
  background-size: auto;
  z-index: 2;
}
.spine.is-expanded.is-collapsing.s-tall { width: 30px; height: 168px; }
.spine.is-expanded.is-collapsing.s-mid { width: 28px; height: 152px; }
.spine.is-expanded.is-collapsing.s-short { width: 24px; height: 136px; }
.spine.is-expanded.is-collapsing.thin { width: 18px; height: 122px; }
.spine.is-expanded.is-collapsing span {
  opacity: 1;
  position: static;
}

.s-tall { height: 168px; width: 30px; }
.s-mid { height: 152px; width: 28px; }
.s-short { height: 136px; width: 24px; }
.spine.is-expanded.s-tall,
.spine.is-expanded.s-mid,
.spine.is-expanded.s-short {
  width: 100px;
  height: 152px;
}

/* book colors */
.bk-clean-code { background-color: #0d1b2a; }
.bk-refactoring { background-color: #7a0d1b; }
.bk-design-patterns { background-color: #0d1b1b; }
.bk-continuous-delivery { background-color: #be2828; }
.bk-phoenix-project { background-color: #3a7ab8; }
.bk-mythical-man-month { background-color: #1b3688; }
.bk-pragmatic-programmer { background-color: #1a1a1a; }
.bk-tdd { background-color: #513688; }
.bk-lean-startup { background-color: #3a3a3a; }
.bk-release-it { background-color: #5a6a88; }
.bk-sre { background-color: #00367a; }
.bk-team-topologies { background-color: #2a6a88; }
.bk-accelerate { background-color: #36445f; }
.bk-ddd { background-color: #1e4a7a; }
.bk-microservices { background-color: #a38851; }
.bk-eaa { background-color: #950d1b; }
.bk-ddia { background-color: #8b3a2f; }
.bk-fundamentals-sa { background-color: #44881b; }
.bk-implementing-ddd { background-color: #b03644; }
.bk-systems-performance { background-color: #00447a; }
.bk-clean-architecture { background-color: #0d1b44; }
.bk-sand { background-color: #c4b7a2; color: #2A261E; }
.bk-cream { background-color: #d2c4ae; color: #2A261E; }

.img-clean-code { background-image: url("covers/clean-code.jpg"); }
.img-refactoring { background-image: url("covers/refactoring.jpg"); }
.img-design-patterns { background-image: url("covers/design-patterns.jpg"); }
.img-pragmatic-programmer { background-image: url("covers/pragmatic-programmer.jpg"); }
.img-continuous-delivery { background-image: url("covers/continuous-delivery.jpg"); }
.img-phoenix-project { background-image: url("covers/phoenix-project.jpg"); }
.img-mythical-man-month { background-image: url("covers/mythical-man-month.jpg"); }
.img-tdd { background-image: url("covers/tdd.jpg"); }
.img-lean-startup { background-image: url("covers/lean-startup.jpg"); }
.img-release-it { background-image: url("covers/release-it.jpg"); }
.img-sre { background-image: url("covers/sre.jpg"); }
.img-team-topologies { background-image: url("covers/team-topologies.jpg"); }
.img-accelerate { background-image: url("covers/accelerate.jpg"); }
.img-ddd { background-image: url("covers/ddd.jpg"); }
.img-microservices { background-image: url("covers/microservices.jpg"); }
.img-eaa { background-image: url("covers/eaa.jpg"); }
.img-ddia { background-image: url("covers/ddia.jpg"); }
.img-fundamentals-sa { background-image: url("covers/fundamentals-sa.jpg"); }
.img-implementing-ddd { background-image: url("covers/implementing-ddd.jpg"); }
.img-systems-performance { background-image: url("covers/systems-performance.jpg"); }
.img-clean-architecture { background-image: url("covers/clean-architecture.jpg"); }

.foot {
  margin-top: 40px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  font-size: 12px;
  color: var(--muted);
  flex-wrap: wrap;
}

/* —— Note view —— */
.note-view {
  position: fixed;
  inset: 0;
  z-index: 60;
  background: var(--wall);
  overflow: auto;
  opacity: 0;
  pointer-events: none;
  /* opacity driven by WAAPI during open/close — no CSS transition */
}
.note-view.is-open {
  opacity: 1;
  pointer-events: auto;
}
.note {
  width: min(100%, var(--col));
  margin: 0 auto;
  padding: 32px var(--pad) 80px;
}
.back-btn {
  border: none;
  background: transparent;
  color: var(--muted);
  font-size: 14px;
  cursor: pointer;
  padding: 8px 0;
  margin-bottom: 28px;
  font-family: inherit;
}
.back-btn:hover { color: var(--ink); }
.note-hero {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  margin-bottom: 36px;
}
.note-cover {
  width: 120px;
  height: 180px;
  flex-shrink: 0;
  border-radius: 2px 3px 0 0;
  background-size: cover;
  background-position: center top;
  background-color: #2a2a2a;
  box-shadow: 0 8px 20px rgba(40,30,20,0.12);
}
.note-cat {
  margin: 0 0 8px;
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.1em;
}
.note-meta h1 {
  font-size: clamp(24px, 4vw, 32px);
  margin: 0 0 8px;
}
.note-author {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}
.note-body {
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
}
.note-body h2 {
  font-family: "Noto Serif SC", serif;
  font-size: 20px;
  margin: 32px 0 12px;
  font-weight: 600;
}
.note-body p { margin: 0 0 1.1em; }
.note-body ul { padding-left: 1.2em; margin: 0 0 1.1em; }
.note-body li { margin-bottom: 0.4em; }
.note-body .placeholder {
  color: var(--muted);
  font-style: italic;
}

/* —— Stage / fixed open + gradient veil (transform/clip only) —— */
.stage {
  position: fixed;
  inset: 0;
  z-index: 70;
  pointer-events: none;
  perspective: 1600px;
}

.open-veil {
  position: fixed;
  inset: 0;
  z-index: 65;
  pointer-events: none;
  overflow: hidden;
  opacity: 0;
}
.open-veil.is-on {
  opacity: 1;
}
.open-veil-blob {
  position: absolute;
  width: 280vmax;
  height: 280vmax;
  left: var(--vx, 50%);
  top: var(--vy, 45%);
  margin-left: -140vmax;
  margin-top: -140vmax;
  border-radius: 50%;
  background:
    radial-gradient(
      circle at center,
      #fffcf6 0%,
      #f5f0e6 32%,
      #e8e0d0 52%,
      #faf9f5 68%,
      #faf9f5 100%
    );
  transform: translateZ(0) scale(0);
  transform-origin: center center;
  will-change: transform, opacity;
  opacity: 1;
}


.flyer {
  position: fixed;
  left: 0;
  top: 0;
  width: 132px;
  height: 198px;
  margin: 0;
  border-radius: 2px 3px 0 0;
  transform-origin: top left;
  transform-style: preserve-3d;
  opacity: 1;
  /* shadow is a sibling layer — not animated (avoids filter/shadow paints) */
}
.flyer-shadow {
  position: absolute;
  inset: -8% -12% -18% -12%;
  border-radius: 4px;
  background: rgba(40, 30, 20, 0.28);
  filter: blur(18px);
  opacity: 0.9;
  z-index: -1;
  pointer-events: none;
  transform: translateZ(0);
}
.flyer.is-ready {
  will-change: transform, opacity;
}
.flyer-inner {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
}
.flyer-back {
  position: absolute;
  inset: 0;
  border-radius: 2px 3px 0 0;
  background: linear-gradient(180deg, #fbf8f0 0%, #f3eee3 100%);
  box-shadow: inset 0 0 0 1px rgba(60, 50, 30, 0.08);
  overflow: hidden;
  padding: 14px 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.flyer-page-title {
  font-family: "Noto Serif SC", serif;
  font-size: 11px;
  font-weight: 600;
  color: #2a261e;
  line-height: 1.35;
  margin-bottom: 4px;
}
.flyer-page-line {
  height: 5px;
  border-radius: 2px;
  background: rgba(60, 50, 30, 0.12);
  width: 100%;
}
.flyer-page-line.short { width: 62%; }
.flyer-page-line.mid { width: 78%; }
.flyer-front {
  position: absolute;
  inset: 0;
  border-radius: 2px 3px 0 0;
  transform-origin: left center;
  transform-style: preserve-3d;
  background-color: #4a3b2f;
  background-image:
    linear-gradient(90deg, rgba(0,0,0,0.18) 0%, transparent 10%),
    linear-gradient(180deg, rgba(255,255,255,0.06), transparent 40%);
  box-shadow:
    inset -2px 0 0 rgba(0,0,0,0.18),
    2px 0 12px rgba(40, 30, 20, 0.18);
  overflow: hidden;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}
.flyer-front.is-animating {
  will-change: transform;
}
.flyer-front.is-spine-face {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  font-family: "Noto Serif SC", serif;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: #F7F3EA;
  display: flex;
  align-items: center;
  justify-content: center;
}
.flyer-spine-label { pointer-events: none; }
.flyer-front.is-cover-ready {
  writing-mode: horizontal-tb;
}
.flyer-front.is-cover-ready .flyer-spine-label {
  display: none;
}

/* Note pre-layout under veil: keep in flow, invisible until reveal */
.note-view.is-preparing {
  display: block !important;
  opacity: 0;
  pointer-events: none;
  transition: none;
}
.note-view.is-open {
  opacity: 1;
  pointer-events: auto;
}

.shelf-view.is-dim { opacity: 0.4; }
.shelf-view { /* opacity via WAAPI during open */ }

/* reduced motion */
@media (prefers-reduced-motion: reduce) {
  :root {
    --t-expand: 1ms;
    --t-collapse: 1ms;
    --t-pull: 1ms;
    --t-flip: 1ms;
    --t-settle: 1ms;
    --t-putback: 1ms;
    --t-land: 1ms;
    --t-veil: 1ms;
  }
  .cover, .spine, .note-view, .shelf-view, .flyer,
  .flyer-front, .flyer-back, .flyer-spine-label, .open-veil, .open-veil-blob {
    transition: none !important;
    animation: none !important;
  }
}

/* mobile */
@media (max-width: 640px) {
  .page { padding: 28px 16px 40px; }
  .covers { gap: 10px; min-height: 176px; }
  .cover { width: 102px; height: 154px; }
  .spines { min-height: 160px; gap: 3px; }
  .spine { height: 132px; width: 24px; font-size: 11px; }
  .s-tall { height: 148px; width: 26px; }
  .s-mid { height: 134px; width: 24px; }
  .s-short { height: 120px; width: 20px; }
  /* resting spines: solid hue only; cover image only when expanded */
.spine[class*="img-"] {
  background-image: none !important;
}
.spine.is-expanded[class*="img-"] {
  background-image: unset;
}
.spine.is-expanded.img-clean-code { background-image: url("covers/clean-code.jpg") !important; }
.spine.is-expanded.img-refactoring { background-image: url("covers/refactoring.jpg") !important; }
.spine.is-expanded.img-design-patterns { background-image: url("covers/design-patterns.jpg") !important; }
.spine.is-expanded.img-pragmatic-programmer { background-image: url("covers/pragmatic-programmer.jpg") !important; }
.spine.is-expanded.img-continuous-delivery { background-image: url("covers/continuous-delivery.jpg") !important; }
.spine.is-expanded.img-phoenix-project { background-image: url("covers/phoenix-project.jpg") !important; }
.spine.is-expanded.img-mythical-man-month { background-image: url("covers/mythical-man-month.jpg") !important; }
.spine.is-expanded.img-tdd { background-image: url("covers/tdd.jpg") !important; }
.spine.is-expanded.img-lean-startup { background-image: url("covers/lean-startup.jpg") !important; }
.spine.is-expanded.img-release-it { background-image: url("covers/release-it.jpg") !important; }
.spine.is-expanded.img-sre { background-image: url("covers/sre.jpg") !important; }
.spine.is-expanded.img-team-topologies { background-image: url("covers/team-topologies.jpg") !important; }
.spine.is-expanded.img-accelerate { background-image: url("covers/accelerate.jpg") !important; }
.spine.is-expanded.img-ddd { background-image: url("covers/ddd.jpg") !important; }
.spine.is-expanded.img-microservices { background-image: url("covers/microservices.jpg") !important; }
.spine.is-expanded.img-eaa { background-image: url("covers/eaa.jpg") !important; }
.spine.is-expanded.img-ddia { background-image: url("covers/ddia.jpg") !important; }
.spine.is-expanded.img-fundamentals-sa { background-image: url("covers/fundamentals-sa.jpg") !important; }
.spine.is-expanded.img-implementing-ddd { background-image: url("covers/implementing-ddd.jpg") !important; }
.spine.is-expanded.img-systems-performance { background-image: url("covers/systems-performance.jpg") !important; }
.spine.is-expanded.img-clean-architecture { background-image: url("covers/clean-architecture.jpg") !important; }

.spine.is-expanded {
    width: 90px;
    height: 136px;
  }
  .spine.is-expanded.is-collapsing {
    width: 24px;
    height: 132px;
  }
  .spine.is-expanded.is-collapsing.s-tall { width: 26px; height: 148px; }
  .spine.is-expanded.is-collapsing.s-mid { width: 24px; height: 134px; }
  .spine.is-expanded.is-collapsing.s-short { width: 20px; height: 120px; }
  .note-hero { flex-direction: column; gap: 16px; }
  .note-cover { width: 100px; height: 150px; }
  .qa-hint { width: 100%; margin-left: 0; margin-top: 4px; }
}

/* Reading path: hide demo/QA chrome unless ?debug=1 */
body:not(.debug-on) .is-debug { display: none !important; }