.method-example {
  position: relative;
  padding: clamp(4.25rem, 7vw, 7rem) 0;
  overflow: hidden;
  border-bottom: 1px solid rgba(20, 17, 14, .14);
  background:
    radial-gradient(circle at 92% 12%, rgba(194, 90, 44, .08), transparent 22%),
    var(--aqluma-ivory-deep);
  color: var(--aqluma-graphite);
}

.method-example::before {
  position: absolute;
  top: 0;
  left: max(1.25rem, calc((100vw - 1180px) / 2 + 4rem));
  width: 1px;
  height: clamp(4rem, 7vw, 7rem);
  background: linear-gradient(var(--clay), rgba(194, 90, 44, .08));
  content: "";
}

.method-example__inner {
  position: relative;
  z-index: 1;
}

.method-example__header {
  display: grid;
  grid-template-columns: minmax(220px, .42fr) minmax(0, 1.58fr);
  gap: clamp(2rem, 4vw, 4.5rem);
  align-items: start;
  margin-bottom: clamp(1.8rem, 3vw, 2.75rem);
}

.method-example__eyebrow {
  display: flex;
  align-items: center;
  gap: .75rem;
  margin: 0;
  color: var(--clay);
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .16em;
}

.method-example__eyebrow::before {
  width: 30px;
  height: 2px;
  background: var(--clay);
  content: "";
}

.method-example__disclaimer {
  width: fit-content;
  margin: .85rem 0 0;
  padding: .38rem .55rem;
  border: 1px solid rgba(20, 17, 14, .2);
  color: #5f5851;
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .045em;
}

.method-example__introduction h2 {
  max-width: 900px;
  margin: 0;
  font: 500 clamp(2.8rem, 5vw, 5.1rem)/.92 var(--sans);
  letter-spacing: -.056em;
  text-wrap: balance;
}

.method-example__introduction h2 em {
  display: block;
  margin-top: .12em;
  color: var(--clay);
  font: italic 400 .74em/1.04 var(--serif);
  letter-spacing: -.03em;
}

.method-example__introduction > p {
  max-width: 780px;
  margin: 1.05rem 0 0;
  padding-left: 1.1rem;
  border-left: 2px solid var(--clay);
  color: #4e4842;
  font-size: clamp(1rem, 1.35vw, 1.16rem);
  line-height: 1.55;
  text-wrap: pretty;
}

.method-example__toc {
  position: absolute;
  z-index: 12;
  top: 48px;
  left: 50%;
  width: min(720px, calc(100% - 2rem));
  margin: 0;
  padding: .75rem;
  border: 1px solid rgba(20, 17, 14, .22);
  background: var(--aqluma-ivory-deep);
  box-shadow: 0 20px 45px rgba(20, 17, 14, .22);
  transform: translateX(-50%);
}

.method-example__toc[hidden] {
  display: none;
}

.method-example__toc-list {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  background: rgba(20, 17, 14, .14);
}

.method-example__toc-list button {
  min-height: 48px;
  padding: .55rem .65rem;
  border: 0;
  background: var(--paper);
  color: #4d4741;
  font: 600 .68rem/1.2 var(--sans);
  text-align: left;
  cursor: pointer;
  transition: background-color .18s ease, color .18s ease;
}

.method-example__toc-list button span {
  display: block;
  margin-bottom: .18rem;
  color: var(--clay);
  font-size: .58rem;
  letter-spacing: .08em;
}

.method-example__toc-list button:hover,
.method-example__toc-list button:focus-visible,
.method-example__toc-list button.is-active {
  background: var(--void);
  color: var(--paper);
}

.method-example__toc-list button:focus-visible {
  position: relative;
  z-index: 1;
  outline: 2px solid var(--clay);
  outline-offset: 2px;
}

.method-book {
  position: relative;
  max-width: 1180px;
  margin: 0 auto;
  outline: none;
}

.method-book:focus-visible {
  outline: 3px solid var(--clay);
  outline-offset: 8px;
}

.method-book__toolbar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  min-height: 48px;
  align-items: center;
  gap: 1rem;
  padding: .55rem .7rem .55rem 1rem;
  border: 1px solid rgba(20, 17, 14, .2);
  border-bottom: 0;
  background: var(--void);
  color: var(--paper);
}

.method-book__indicator {
  margin: 0;
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .045em;
}

.method-book__chooser {
  min-height: 34px;
  padding: .45rem .7rem;
  border: 1px solid rgba(244, 239, 230, .3);
  background: transparent;
  color: var(--paper);
  font: 700 .67rem var(--sans);
  cursor: pointer;
}

.method-book__chooser::after {
  margin-left: .5rem;
  color: var(--clay);
  content: "＋";
}

.method-book__chooser[aria-expanded="true"]::after {
  content: "−";
}

.method-book__chooser:hover,
.method-book__chooser:focus-visible {
  border-color: var(--clay);
}

.method-book__chooser:focus-visible {
  outline: 2px solid var(--clay);
  outline-offset: 3px;
}

.method-book__top-navigation {
  display: flex;
  gap: .4rem;
}

.method-book__nav--top {
  min-height: 34px;
  padding: .45rem .65rem;
  border-color: rgba(244, 239, 230, .26);
  background: transparent;
  color: var(--paper);
  font-size: .64rem;
}

.method-book__nav--top:disabled {
  border-color: rgba(244, 239, 230, .12);
  background: transparent;
  color: rgba(244, 239, 230, .35);
}

.method-book__spread {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 22px minmax(0, 1fr);
  min-height: var(--method-page-height, 660px);
  border: 1px solid rgba(20, 17, 14, .2);
  background: #d8cdbc;
  box-shadow: 0 34px 70px rgba(45, 35, 26, .16);
  perspective: 1800px;
  transform-origin: center bottom;
  touch-action: pan-y;
}

.method-example.is-motion-ready .method-book {
  opacity: 0;
  transform: translateY(22px) scale(.99);
  transition: opacity .7s ease, transform .8s cubic-bezier(.2, .7, .2, 1);
}

.method-example.is-motion-ready.is-visible .method-book {
  opacity: 1;
  transform: none;
}

.method-page {
  position: relative;
  min-width: 0;
  min-height: var(--method-page-height, 660px);
  padding: clamp(2rem, 2.7vw, 2.75rem) clamp(1.75rem, 2.7vw, 2.75rem) 3rem clamp(3.5rem, 4.2vw, 4.35rem);
  background:
    linear-gradient(90deg, transparent 0 3rem, rgba(194, 90, 44, .15) 3rem 3.07rem, transparent 3.07rem),
    repeating-linear-gradient(0deg, transparent 0 37px, rgba(20, 17, 14, .075) 37px 38px),
    var(--paper);
  backface-visibility: hidden;
  transform-style: preserve-3d;
}

.method-page--left {
  box-shadow: inset -22px 0 32px -30px rgba(20, 17, 14, .5);
}

.method-page--right {
  box-shadow: inset 22px 0 32px -30px rgba(20, 17, 14, .5);
}

.method-page::before {
  position: absolute;
  top: 1rem;
  bottom: 1rem;
  left: 1rem;
  width: 10px;
  background: radial-gradient(circle, rgba(20, 17, 14, .28) 0 2px, transparent 2.5px) 0 8px / 10px 28px repeat-y;
  content: "";
}

.method-page--right::after {
  position: absolute;
  right: 2rem;
  bottom: 2rem;
  width: 92px;
  height: 58px;
  border: 1px solid rgba(194, 90, 44, .24);
  border-radius: 50%;
  transform: rotate(-13deg);
  content: "";
}

.method-page__number {
  position: absolute;
  right: 1.35rem;
  bottom: 1.15rem;
  color: #827970;
  font-size: .65rem;
  font-weight: 700;
  letter-spacing: .1em;
}

.method-page--left .method-page__number {
  right: auto;
  left: 1.35rem;
}

.method-page__subject {
  min-height: 66px;
  padding-bottom: .75rem;
  border-bottom: 1px solid rgba(20, 17, 14, .22);
}

.method-page__subject p {
  margin: 0 0 .35rem;
  color: var(--clay);
  font-size: .66rem;
  font-weight: 700;
  letter-spacing: .13em;
  text-transform: uppercase;
}

.method-page__subject h3 {
  margin: 0;
  font: italic 500 clamp(1.45rem, 1.9vw, 1.85rem)/1.08 var(--serif);
  letter-spacing: -.02em;
}

.method-book__spine {
  position: relative;
  z-index: 4;
  background:
    linear-gradient(90deg, rgba(20, 17, 14, .2), transparent 38%, transparent 62%, rgba(20, 17, 14, .18)),
    #e5dccf;
  box-shadow: inset 0 0 12px rgba(20, 17, 14, .12);
}

.method-book__spine::before {
  position: absolute;
  inset: 1rem 6px;
  background: radial-gradient(circle, rgba(20, 17, 14, .3) 0 2px, transparent 2.5px) center 4px / 10px 28px repeat-y;
  content: "";
}

.method-stage {
  margin-top: 1.1rem;
}

.method-stage + .method-stage {
  margin-top: 1.1rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(20, 17, 14, .23);
}

.method-stage__heading {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: .7rem;
  align-items: baseline;
}

.method-stage__heading span {
  color: var(--clay);
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .1em;
}

.method-stage__heading h4 {
  margin: 0;
  font: italic 500 clamp(1.2rem, 1.55vw, 1.5rem)/1.1 var(--serif);
}

.exercise-block {
  margin-top: .9rem;
  padding: .8rem .9rem;
  border: 1px solid rgba(20, 17, 14, .2);
  background: rgba(244, 239, 230, .76);
}

.exercise-block__label,
.student-attempt__label,
.teacher-note__label,
.ai-request__label,
.method-reasoning__label,
.student-voice__label {
  margin: 0 0 .45rem;
  color: var(--clay);
  font-size: .65rem;
  font-weight: 700;
  letter-spacing: .11em;
  text-transform: uppercase;
}

.exercise-block > p:last-child,
.method-reasoning > p:last-child {
  margin: 0;
  color: var(--void);
  font-size: .9rem;
  font-weight: 600;
  line-height: 1.5;
}

.student-attempt {
  margin: .9rem 0 0;
  padding: 0 .65rem .75rem;
  border-bottom: 1px solid rgba(20, 17, 14, .18);
}

.student-attempt blockquote {
  margin: .45rem 0 0;
  color: #3d3935;
  font: italic 400 clamp(1.15rem, 1.7vw, 1.45rem)/1.28 var(--font-accent);
  transform: rotate(-.6deg);
}

.student-voice {
  margin-top: .7rem;
  padding: .75rem .9rem;
  border: 1px dashed rgba(194, 90, 44, .5);
  background: rgba(244, 239, 230, .7);
}

.student-voice blockquote {
  margin: 0;
  color: #2f2a26;
  font: italic 400 1.05rem/1.4 var(--font-accent);
}

.teacher-note {
  width: min(94%, 430px);
  margin: .75rem 0 0 auto;
  padding: .8rem .9rem;
  border: 1px solid rgba(194, 90, 44, .56);
  background: rgba(244, 239, 230, .86);
  box-shadow: 7px 7px 0 rgba(194, 90, 44, .08);
  transform: rotate(.6deg);
}

.teacher-note p:last-child {
  margin: 0;
  color: var(--clay);
  font: italic 500 1.08rem/1.38 var(--serif);
}

.ai-request {
  position: relative;
  margin-top: .7rem;
  padding: .85rem .95rem;
  border-left: 3px solid var(--clay);
  background: #4b443d;
  color: var(--paper);
}

.ai-request blockquote {
  margin: 0;
  color: #ece4db;
  font: italic 400 1rem/1.42 var(--serif);
}

.method-reasoning {
  margin-top: .7rem;
  padding: .75rem .85rem;
  border-left: 2px solid var(--aqluma-moss);
  background: rgba(74, 87, 68, .09);
}

.exercise-block--retry {
  margin-top: .7rem;
}

.method-reveal {
  min-height: 42px;
  margin-top: .7rem;
  padding: .6rem .8rem;
  border: 1px solid rgba(20, 17, 14, .34);
  background: transparent;
  color: var(--void);
  font: 700 .7rem var(--sans);
  letter-spacing: .055em;
  cursor: pointer;
  transition: border-color .2s ease, background-color .2s ease, color .2s ease;
}

.method-reveal:hover,
.method-reveal:focus-visible,
.method-reveal[aria-expanded="true"] {
  border-color: var(--clay);
  background: var(--clay);
  color: var(--paper);
}

.method-reveal:focus-visible {
  outline: 2px solid var(--clay);
  outline-offset: 4px;
}

.method-answer {
  margin-top: .75rem;
  padding: .85rem 1rem;
  border: 1px solid rgba(74, 87, 68, .34);
  background: rgba(74, 87, 68, .09);
}

.method-answer[hidden] {
  display: none;
}

.method-answer p {
  margin: 0;
  color: #374033;
  font-size: .86rem;
  font-weight: 600;
  line-height: 1.5;
}

.method-book__corner {
  position: absolute;
  z-index: 6;
  bottom: 0;
  width: 60px;
  height: 60px;
  padding: 0;
  border: 0;
  background: rgba(194, 90, 44, .18);
  cursor: pointer;
  transition: background-color .18s ease, transform .18s ease;
}

.method-book__corner--previous {
  left: 0;
  clip-path: polygon(0 0, 100% 100%, 0 100%);
  transform-origin: left bottom;
}

.method-book__corner--next {
  right: 0;
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
  transform-origin: right bottom;
}

.method-book__corner:hover,
.method-book__corner:focus-visible {
  background: rgba(194, 90, 44, .62);
  transform: scale(1.08);
}

.method-book__corner:focus-visible {
  outline: 3px solid var(--void);
  outline-offset: -8px;
}

.method-book__corner:disabled {
  opacity: .18;
  cursor: not-allowed;
  transform: none;
}

.method-book__controls {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
  margin-top: 1rem;
}

.method-book__nav {
  min-height: 46px;
  padding: .75rem 1rem;
  border: 1px solid rgba(20, 17, 14, .3);
  background: var(--paper);
  color: var(--void);
  font: 700 .72rem var(--sans);
  letter-spacing: .045em;
  cursor: pointer;
  transition: border-color .18s ease, background-color .18s ease, color .18s ease;
}

.method-book__nav:first-child {
  justify-self: start;
}

.method-book__nav:last-child {
  justify-self: end;
}

.method-book__nav:hover,
.method-book__nav:focus-visible {
  border-color: var(--clay);
  background: var(--clay);
  color: var(--paper);
}

.method-book__nav:focus-visible {
  outline: 2px solid var(--clay);
  outline-offset: 3px;
}

.method-book__nav:disabled {
  border-color: rgba(20, 17, 14, .15);
  background: rgba(244, 239, 230, .5);
  color: #9a9188;
  cursor: not-allowed;
}

.method-book__pages {
  color: #756c63;
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.method-book__measure {
  position: absolute;
  top: 0;
  left: -200vw;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 22px minmax(0, 1fr);
  gap: 0;
  visibility: hidden;
  pointer-events: none;
}

.method-book__measure .method-page {
  min-height: 0 !important;
}

.method-book__spread.is-turning-next .method-page--right {
  z-index: 5;
  animation: method-turn-next .28s ease-in forwards;
  transform-origin: left center;
}

.method-book__spread.is-turning-previous .method-page--left {
  z-index: 5;
  animation: method-turn-previous .28s ease-in forwards;
  transform-origin: right center;
}

.method-book__spread.is-turn-complete .method-page {
  animation: method-page-settle .28s ease-out;
}

.method-example__closing {
  max-width: 850px;
  margin: clamp(2.8rem, 5vw, 4.5rem) auto 0;
  color: var(--void);
  font: italic 500 clamp(1.65rem, 3vw, 2.55rem)/1.2 var(--serif);
  text-align: center;
  text-wrap: balance;
}

.method-example__closing::before {
  display: block;
  width: 58px;
  height: 2px;
  margin: 0 auto 1.4rem;
  background: var(--clay);
  content: "";
}

@keyframes method-turn-next {
  0% { transform: rotateY(0); filter: brightness(1); }
  100% { transform: rotateY(-86deg); filter: brightness(.88); }
}

@keyframes method-turn-previous {
  0% { transform: rotateY(0); filter: brightness(1); }
  100% { transform: rotateY(86deg); filter: brightness(.88); }
}

@keyframes method-page-settle {
  from { opacity: .75; transform: translateY(4px); }
  to { opacity: 1; transform: none; }
}

@media (max-width: 900px) {
  .method-example__header {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .method-example__toc-list {
    display: flex;
    overflow-x: auto;
    overscroll-behavior-x: contain;
    scrollbar-width: thin;
  }

  .method-book__measure {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .method-book__measure .method-book__spine {
    display: none;
  }

  .method-example__toc-list button {
    flex: 0 0 132px;
  }

  .method-book__spread {
    grid-template-columns: 1fr;
    min-height: 0;
    gap: 1rem;
    border: 0;
    background: transparent;
    box-shadow: none;
  }

  .method-book__spine,
  .method-book__corner {
    display: none;
  }

  .method-page {
    min-height: 0;
    padding: 3rem 3rem 3.5rem 4.5rem;
    border: 1px solid rgba(20, 17, 14, .2);
    box-shadow: 0 18px 40px rgba(45, 35, 26, .12);
  }

  .method-book__spread.is-turning-next .method-page--right,
  .method-book__spread.is-turning-previous .method-page--left {
    animation: method-mobile-leave .26s ease-in forwards;
    transform-origin: center;
  }
}

@keyframes method-mobile-leave {
  to { opacity: 0; transform: translateX(-18px); }
}

@media (max-width: 640px) {
  .method-example {
    padding: 3.75rem 0 4.5rem;
  }

  .method-example::before {
    left: 2rem;
    height: 3.4rem;
  }

  .method-example__header {
    gap: 1.35rem;
    margin-bottom: 1.75rem;
  }

  .method-example__introduction h2 {
    font-size: clamp(2.65rem, 12.5vw, 3.8rem);
    line-height: .92;
  }

  .method-example__introduction h2 em {
    font-size: .77em;
    line-height: 1.06;
  }

  .method-example__introduction > p {
    margin-top: 1.25rem;
    font-size: 1rem;
  }

  .method-example__toc {
    top: 102px;
    width: calc(100% - 1rem);
    padding-inline: .65rem;
  }

  .method-book__toolbar {
    grid-template-columns: minmax(0, 1fr) auto;
    min-height: 102px;
    gap: .55rem;
    padding: .65rem .7rem;
  }

  .method-book__indicator {
    grid-column: 1 / -1;
  }

  .method-book__chooser {
    justify-self: start;
  }

  .method-book__top-navigation {
    justify-self: end;
  }

  .method-book__indicator {
    font-size: .7rem;
  }

  .method-page {
    padding: 2rem 1.1rem 2.75rem 3.15rem;
    background:
      linear-gradient(90deg, transparent 0 2.25rem, rgba(194, 90, 44, .15) 2.25rem 2.31rem, transparent 2.31rem),
      repeating-linear-gradient(0deg, transparent 0 34px, rgba(20, 17, 14, .075) 34px 35px),
      var(--paper);
  }

  .method-page::before {
    left: .65rem;
  }

  .method-page__subject {
    min-height: 72px;
  }

  .method-page__subject h3 {
    font-size: 1.55rem;
  }

  .method-stage {
    margin-top: 1.35rem;
  }

  .method-stage__heading {
    grid-template-columns: 28px 1fr;
    gap: .45rem;
  }

  .method-stage__heading h4 {
    font-size: 1.4rem;
  }

  .exercise-block {
    margin-top: 1rem;
    padding: .9rem;
  }

  .exercise-block > p:last-child,
  .method-reasoning > p:last-child {
    font-size: .88rem;
  }

  .student-attempt {
    margin-top: 1.25rem;
    padding-inline: .25rem;
  }

  .student-attempt blockquote {
    font-size: 1.35rem;
  }

  .teacher-note {
    width: 100%;
    margin-top: 1rem;
  }

  .ai-request blockquote {
    font-size: .98rem;
  }

  .method-reveal {
    width: 100%;
  }

  .method-book__controls {
    grid-template-columns: 1fr 1fr;
  }

  .method-book__nav {
    width: 100%;
  }

  .method-book__nav--top {
    width: auto;
    padding-inline: .5rem;
    font-size: .6rem;
  }

  .method-book__pages {
    grid-column: 1 / -1;
    grid-row: 1;
    text-align: center;
  }

  .method-example__closing {
    font-size: 1.65rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .method-example.is-motion-ready .method-book,
  .method-example__toc-list button,
  .method-book__corner,
  .method-book__nav,
  .method-reveal {
    opacity: 1;
    transform: none;
    animation: none;
    transition: none;
  }
}