:root {
  --paper: #f4f1ea;
  --paper-2: #ebe7df;
  --white: #fffdf8;
  --ink: #17223b;
  --ink-soft: #33415c;
  --muted: #737987;
  --line: #cbc8c0;
  --blue: #155eef;
  --blue-soft: #dce7ff;
  --orange: #ee6c3b;
  --orange-soft: #ffe2d5;
  --stage: #e5e9ef;
  --card-shadow: 0 14px 30px rgba(23, 34, 59, .07);
  --card-edge: 1px solid rgba(23, 34, 59, .1);
}

* { box-sizing: border-box; }

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: #c9c6bf;
}

body {
  color: var(--ink);
  font-family: system-ui, -apple-system, "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

button,
input { font: inherit; }

button { color: inherit; }

button:focus-visible,
input:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 3px;
}

#presentation {
  position: fixed;
  inset: 0;
  overflow: hidden;
}

.deck {
  position: absolute;
  top: 0;
  left: 0;
  width: 1600px;
  height: 900px;
  overflow: hidden;
  transform-origin: top left;
  background: var(--paper);
  box-shadow: 0 24px 80px rgba(23, 34, 59, .24);
}

.slide {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  padding: 58px 88px 70px;
  overflow: hidden;
  opacity: 0;
  visibility: hidden;
  transform: translateX(18px);
  transition: opacity .22s ease, transform .22s ease, visibility 0s linear .22s;
  pointer-events: none;
}

.slide::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 12px;
  height: 100%;
  background: var(--blue);
}

.slide.is-active {
  opacity: 1;
  visibility: visible;
  transform: translateX(0);
  transition-delay: 0s;
  pointer-events: auto;
}

.slide-header {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 40px;
  align-items: end;
  margin-bottom: 32px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
}

.slide-kicker {
  margin: 0;
  color: var(--blue);
  font-size: 18px;
  font-weight: 800;
  letter-spacing: .04em;
  font-variant-numeric: tabular-nums;
}

.slide h2 {
  margin: 0;
  font-size: 46px;
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -.045em;
}

.x-color { color: var(--blue); }
.y-color { color: var(--orange); }

.matrix {
  position: relative;
  display: grid;
  align-items: center;
  gap: 5px 18px;
  padding: 7px 20px;
  font-family: Georgia, "Times New Roman", serif;
  text-align: center;
}

.matrix::before,
.matrix::after {
  content: "";
  position: absolute;
  top: -2px;
  bottom: -2px;
  width: 15px;
}

.matrix::before {
  left: 0;
  border-left: 2px solid currentColor;
  border-radius: 50% 0 0 50%;
}

.matrix::after {
  right: 0;
  border-right: 2px solid currentColor;
  border-radius: 0 50% 50% 0;
}

.matrix.vector { grid-template-columns: 1fr; }
.matrix.two-by-two { grid-template-columns: repeat(2, minmax(34px, 1fr)); }
.matrix.two-by-three { grid-template-columns: repeat(3, minmax(42px, 1fr)); }
.matrix.three { padding-block: 4px; }
.matrix.compact { gap: 0; padding-inline: 14px; font-size: 23px; }
.matrix .one { color: var(--orange); font-weight: 800; }

.matrix-explainer {
  position: absolute;
  inset: 0;
  z-index: 200;
  display: grid;
  place-items: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity .2s ease, visibility 0s linear .2s;
  pointer-events: none;
}

.matrix-explainer.is-open {
  opacity: 1;
  visibility: visible;
  transition-delay: 0s;
  pointer-events: auto;
}

.matrix-explainer-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(23, 34, 59, .88);
  backdrop-filter: blur(8px);
}

.matrix-explainer-panel {
  position: relative;
  width: 1320px;
  height: 720px;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  overflow: hidden;
  border-top: 8px solid var(--blue);
  background: var(--paper);
  box-shadow: 0 30px 90px rgba(0, 0, 0, .32);
}

.matrix-explainer-panel::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 10px;
  height: 100%;
  background: var(--orange);
}

.matrix-explainer-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 55px;
  padding: 28px 0 20px;
  border-bottom: 1px solid var(--line);
}

.matrix-explainer-header p {
  margin: 0 0 8px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 850;
  letter-spacing: .18em;
}

.matrix-explainer-header h2 {
  margin: 0;
  font-size: 31px;
  letter-spacing: -.035em;
}

.matrix-explainer-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-right: 14px;
}

.matrix-explainer-actions button {
  padding: 9px 14px;
  border: 1px solid var(--ink);
  background: transparent;
  color: var(--ink);
  font-size: 13px;
  font-weight: 750;
  cursor: pointer;
}

#matrix-close-button {
  display: grid;
  place-items: center;
  width: 39px;
  height: 39px;
  padding: 0;
  border-color: var(--ink);
  background: var(--ink);
  color: #fff;
  font-size: 27px;
  line-height: 1;
}

.matrix-explainer-body {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 42px;
  min-height: 0;
  padding: 28px 69px 20px 55px;
}

.matrix-step-list {
  display: grid;
  align-content: center;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.matrix-step-list li {
  display: grid;
  grid-template-columns: 38px 1fr;
  gap: 3px 12px;
  align-items: center;
  padding: 15px 14px;
  border-left: 3px solid var(--line);
  color: var(--muted);
  transition: border-color .24s ease, background .24s ease, color .24s ease;
}

.matrix-step-list li > span {
  grid-row: 1 / span 2;
  font-size: 13px;
  font-weight: 850;
  font-variant-numeric: tabular-nums;
}

.matrix-step-list li strong { font-size: 15px; }
.matrix-step-list li small { font-size: 12px; }

.matrix-explainer[data-stage="1"] [data-step-marker="1"],
.matrix-explainer[data-stage="2"] [data-step-marker="2"],
.matrix-explainer[data-stage="3"] [data-step-marker="2"],
.matrix-explainer[data-stage="4"] [data-step-marker="3"],
.matrix-explainer[data-stage="5"] [data-step-marker="2"],
.matrix-explainer[data-stage="6"] [data-step-marker="3"],
.matrix-explainer[data-stage="7"] .matrix-step-list li {
  border-left-color: var(--blue);
  background: var(--blue-soft);
  color: var(--ink);
}

.matrix-animation-stage {
  display: grid;
  grid-template-rows: 190px 175px auto;
  min-width: 0;
}

.matrix-animation-equation {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 28px;
  font: 36px Georgia, "Times New Roman", serif;
}

.matrix-animation-block {
  display: flex;
  align-items: center;
  gap: 12px;
}

.matrix-symbol {
  color: var(--muted);
  font: italic 21px Georgia, serif;
}

.matrix-operator { color: var(--muted); }
.animated-matrix { font-size: 29px; }
.animated-vector,
.animated-result { font-size: 29px; }

.animated-matrix > span,
.animated-vector > span,
.animated-result > span {
  min-width: 38px;
  padding: 5px 7px;
  transition: color .22s ease, background .22s ease, transform .22s ease;
}

.matrix-explainer[data-stage="1"] .animated-matrix > span:nth-child(-n+3),
.matrix-explainer[data-stage="2"] .animated-matrix > span:nth-child(-n+3),
.matrix-explainer[data-stage="3"] .animated-matrix > span:nth-child(-n+3) {
  background: var(--blue-soft);
  color: var(--blue);
  transform: translateY(-2px);
}

.matrix-explainer[data-stage="4"] .animated-matrix > span:nth-child(n+4),
.matrix-explainer[data-stage="5"] .animated-matrix > span:nth-child(n+4),
.matrix-explainer[data-stage="6"] .animated-matrix > span:nth-child(n+4) {
  background: var(--orange-soft);
  color: var(--orange);
  transform: translateY(2px);
}

.matrix-explainer[data-stage="1"] .animated-vector > span,
.matrix-explainer[data-stage="2"] .animated-vector > span,
.matrix-explainer[data-stage="3"] .animated-vector > span {
  background: var(--blue-soft);
}

.matrix-explainer[data-stage="4"] .animated-vector > span,
.matrix-explainer[data-stage="5"] .animated-vector > span,
.matrix-explainer[data-stage="6"] .animated-vector > span {
  background: var(--orange-soft);
}

.animated-result > span {
  color: var(--muted);
  font-weight: 800;
}

.matrix-explainer[data-stage="3"] [data-explainer-result="x"],
.matrix-explainer[data-stage="4"] [data-explainer-result="x"],
.matrix-explainer[data-stage="5"] [data-explainer-result="x"],
.matrix-explainer[data-stage="6"] [data-explainer-result="x"],
.matrix-explainer[data-stage="7"] [data-explainer-result="x"] {
  background: var(--blue);
  color: #fff;
  transform: scale(1.08);
}

.matrix-explainer[data-stage="6"] [data-explainer-result="y"],
.matrix-explainer[data-stage="7"] [data-explainer-result="y"] {
  background: var(--orange);
  color: #fff;
  transform: scale(1.08);
}

.matrix-product-area {
  display: grid;
  grid-template-rows: 1fr 1fr;
  gap: 9px;
  align-content: center;
}

.matrix-product-row {
  display: grid;
  grid-template-columns: 48px 1fr 22px 62px;
  gap: 12px;
  align-items: center;
  min-height: 72px;
  padding: 12px 18px;
  border-top: 1px solid var(--line);
  background: var(--white);
  opacity: .16;
  transform: translateY(5px);
  transition: opacity .28s ease, transform .28s ease;
}

.matrix-product-row > strong {
  font: 800 27px Georgia, "Times New Roman", serif;
  text-align: right;
}

.product-coordinate {
  font: italic 27px Georgia, serif;
  font-weight: 800;
}

.product-terms {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  font: 21px Georgia, "Times New Roman", serif;
}

.product-terms b {
  color: var(--muted);
  font-weight: 400;
}

.product-terms > span {
  padding: 6px 8px;
  background: var(--paper-2);
  opacity: 0;
  transform: translateY(7px);
  transition: opacity .25s ease, transform .25s ease;
}

.matrix-explainer[data-stage="2"] .product-row-x,
.matrix-explainer[data-stage="3"] .product-row-x,
.matrix-explainer[data-stage="5"] .product-row-x,
.matrix-explainer[data-stage="6"] .product-row-x,
.matrix-explainer[data-stage="7"] .product-row-x,
.matrix-explainer[data-stage="5"] .product-row-y,
.matrix-explainer[data-stage="6"] .product-row-y,
.matrix-explainer[data-stage="7"] .product-row-y {
  opacity: 1;
  transform: translateY(0);
}

.matrix-explainer[data-stage="2"] .product-row-x .product-terms > span,
.matrix-explainer[data-stage="3"] .product-row-x .product-terms > span,
.matrix-explainer[data-stage="5"] .product-terms > span,
.matrix-explainer[data-stage="6"] .product-terms > span,
.matrix-explainer[data-stage="7"] .product-terms > span {
  opacity: 1;
  transform: translateY(0);
}

.product-terms > span:nth-of-type(1) { transition-delay: .05s; }
.product-terms > span:nth-of-type(2) { transition-delay: .23s; }
.product-terms > span:nth-of-type(3) { transition-delay: .41s; }

.matrix-explainer[data-stage="5"] .product-row-x,
.matrix-explainer[data-stage="6"] .product-row-x { opacity: .28; }

.matrix-animation-caption {
  align-self: end;
  margin: 9px 0 0;
  padding: 12px 16px;
  border-left: 5px solid var(--blue);
  background: var(--blue-soft);
  color: var(--ink);
  font-size: 16px;
  text-align: center;
}

.matrix-explainer-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 55px;
  padding: 17px 14px 22px 0;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

.matrix-explainer-footer strong {
  color: var(--ink);
  font-size: 16px;
}

.fullscreen-button {
  position: absolute;
  z-index: 50;
  top: 22px;
  right: 30px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 13px;
  border: 1px solid rgba(23,34,59,.18);
  background: rgba(255,253,248,.86);
  color: var(--ink-soft);
  font-size: 14px;
  cursor: pointer;
}

.edge-button {
  position: absolute;
  z-index: 45;
  top: 50%;
  width: 48px;
  height: 84px;
  border: 1px solid rgba(23,34,59,.18);
  background: rgba(255,253,248,.82);
  color: var(--ink);
  font-size: 46px;
  line-height: 1;
  transform: translateY(-50%);
  cursor: pointer;
}

.edge-button:disabled {
  opacity: .22;
  cursor: default;
}

.previous-button { left: 18px; }
.next-button { right: 28px; }

.presentation-footer {
  position: absolute;
  z-index: 48;
  left: 88px;
  right: 88px;
  bottom: 24px;
  display: grid;
  grid-template-columns: 200px 1fr 80px;
  gap: 24px;
  align-items: center;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: .04em;
}

.presentation-footer > span:last-child {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.progress-track {
  height: 2px;
  overflow: hidden;
  background: #d8d5ce;
}

#progress-bar {
  width: 7.69%;
  height: 100%;
  background: var(--blue);
  transition: width .2s ease;
}

.title-slide {
  display: block;
  padding: 0;
  background: var(--paper);
  color: var(--ink);
}

.deck.dark-slide-active .fullscreen-button,
.deck.dark-slide-active .edge-button {
  border-color: rgba(255,255,255,.22);
  background: rgba(23,34,59,.74);
  color: var(--white);
}

.deck.dark-slide-active .presentation-footer { color: #aab3c8; }
.deck.dark-slide-active .progress-track { background: rgba(255,255,255,.18); }

.title-slide::after {
  width: 20px;
  background: var(--orange);
}

.cover-copy {
  position: absolute;
  inset: 0 720px 0 0;
  padding: 65px 76px 76px 92px;
  background:
    linear-gradient(90deg, transparent 99.82%, var(--line) 99.82%),
    var(--paper);
}

.cover-meta {
  display: flex;
  justify-content: space-between;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: .1em;
  font-variant-numeric: tabular-nums;
}

.cover-series {
  margin: 78px 0 19px;
  color: var(--blue);
  font-size: 15px;
  font-weight: 850;
  letter-spacing: .22em;
}

.cover-copy h1 {
  margin: 0;
  font-size: 82px;
  font-weight: 820;
  line-height: 1.05;
  letter-spacing: -.06em;
}

.cover-subject {
  position: absolute;
  left: 92px;
  right: 76px;
  bottom: 95px;
  display: grid;
  grid-template-columns: 55px 1fr;
  gap: 18px;
  align-items: start;
  padding-top: 20px;
  border-top: 3px solid var(--ink);
}

.cover-subject > span {
  color: var(--orange);
  font-size: 16px;
  font-weight: 850;
}

.cover-subject p {
  margin: 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.55;
}

.cover-subject strong {
  color: var(--ink);
  font-size: 26px;
}

.cover-visual {
  position: absolute;
  inset: 0 20px 0 880px;
  overflow: hidden;
  background: var(--ink);
}

.cover-visual > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 58% center;
}

.cover-image-shade {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(23,34,59,.05), rgba(23,34,59,.18)),
    linear-gradient(90deg, rgba(23,34,59,.32), transparent 55%);
}

.cover-image-label {
  position: absolute;
  top: 68px;
  left: 50px;
  margin: 0;
  color: #fff;
  font-size: 13px;
  font-weight: 850;
  letter-spacing: .2em;
}

.cover-equation {
  position: absolute;
  left: 50px;
  right: 50px;
  bottom: 92px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 24px 26px;
  border-top: 2px solid #8eb3ff;
  background: rgba(23,34,59,.82);
  color: #fff;
  backdrop-filter: blur(8px);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 30px;
}

.cover-equation .matrix {
  gap: 3px 13px;
  font-size: 22px;
}

.cover-coordinate {
  position: absolute;
  top: 134px;
  right: 42px;
  bottom: 230px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: flex-end;
  color: rgba(255,255,255,.78);
  font: 14px Georgia, serif;
}

.cover-coordinate i {
  position: absolute;
  top: 23px;
  right: 7px;
  bottom: 23px;
  width: 1px;
  background: rgba(255,255,255,.42);
}

.agenda-layout {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 210px;
  align-content: start;
  gap: 0 55px;
  padding: 2px 70px 45px;
}

.agenda-card {
  display: grid;
  grid-column: 1;
  grid-template-columns: 130px 1fr 72px;
  gap: 30px;
  align-items: center;
  min-height: 125px;
  padding: 18px 10px 18px 0;
  border-top: 1px solid var(--line);
}

.agenda-card:last-of-type { border-bottom: 1px solid var(--line); }

.agenda-index {
  display: grid;
  grid-template-columns: 42px 1fr;
  gap: 13px;
  align-items: center;
}

.agenda-index > span {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  background: var(--ink);
  color: #fff;
  font-size: 14px;
  font-weight: 850;
  font-variant-numeric: tabular-nums;
}

.agenda-index small {
  color: var(--blue);
  font-size: 11px;
  font-weight: 850;
  letter-spacing: .12em;
}

.agenda-copy h3 {
  margin: 0 0 7px;
  font-size: 26px;
  letter-spacing: -.035em;
}

.agenda-copy p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.45;
}

.agenda-pages {
  justify-self: end;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  letter-spacing: .08em;
}

.agenda-side-note {
  grid-column: 2;
  grid-row: 1 / span 4;
  display: grid;
  align-content: center;
  justify-items: center;
  border-left: 1px solid var(--line);
}

.agenda-side-note span {
  color: var(--orange);
  font: 150px/.85 Georgia, "Times New Roman", serif;
}

.agenda-side-note p {
  margin: 26px 0 0;
  color: var(--blue);
  font-size: 13px;
  font-weight: 850;
  letter-spacing: .25em;
  writing-mode: vertical-rl;
}

.motivation-layout {
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 54px;
  align-items: center;
  padding: 10px 36px 70px;
}

.question-stack { display: grid; gap: 18px; }

.big-question {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 18px;
  align-items: start;
  padding: 27px 30px;
  border-top: 1px solid var(--ink);
  background: var(--white);
  border-inline: var(--card-edge);
  border-bottom: var(--card-edge);
  box-shadow: var(--card-shadow);
}

.big-question > span {
  color: var(--blue);
  font-size: 17px;
  font-weight: 850;
  letter-spacing: .08em;
}

.big-question p {
  margin: 0;
  font-size: 29px;
  line-height: 1.38;
}

.big-question strong {
  font-size: 38px;
  letter-spacing: -.03em;
}

.operation-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.operation-compare article {
  min-height: 320px;
  padding: 26px 24px;
  border: 1px solid var(--line);
  background: transparent;
  box-shadow: var(--card-shadow);
}

.operation-compare article.featured {
  border: 0;
  background: var(--ink);
  color: var(--white);
}

.card-label {
  margin: 0 0 28px;
  color: var(--muted);
  font-size: 16px;
  font-weight: 750;
}

.featured .card-label { color: #aab3c8; }

.mini-math,
.dot-product {
  display: flex;
  height: 140px;
  align-items: center;
  justify-content: center;
  gap: 15px;
}

.mini-grid {
  display: grid;
  grid-template-columns: repeat(2, 36px);
  gap: 6px;
}

.mini-grid i {
  display: grid;
  place-items: center;
  height: 36px;
  background: var(--paper-2);
  font-style: normal;
}

.dot-product { font: 28px Georgia, serif; }
.row-token { padding: 10px 4px; border-bottom: 2px solid var(--blue); }
.operation-compare article > strong { display: block; margin-top: 25px; font-size: 17px; text-align: center; }

.takeaway {
  position: absolute;
  left: 88px;
  right: 88px;
  bottom: 64px;
  margin: 0;
  padding: 13px 20px;
  border-left: 5px solid var(--blue);
  background: var(--blue-soft);
  color: var(--ink);
  font-size: 19px;
  text-align: center;
}

.coordinate-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 86px;
  align-items: center;
  padding: 0 72px 36px;
}

.pixel-diagram {
  position: relative;
  width: 520px;
  height: 485px;
}

.pixel-grid {
  position: absolute;
  top: 58px;
  left: 74px;
  display: grid;
  grid-template-columns: repeat(5, 75px);
  grid-template-rows: repeat(5, 68px);
  border: 2px solid var(--ink);
  background: var(--white);
}

.pixel-grid i {
  border-right: 1px solid #aeb4bf;
  border-bottom: 1px solid #aeb4bf;
  background: #eef2f7;
}

.pixel-grid i:nth-child(5n) { border-right: 0; }
.pixel-grid i:nth-last-child(-n+5) { border-bottom: 0; }
.pixel-grid i.focus { background: var(--blue); box-shadow: inset 0 0 0 7px var(--blue-soft); }

.x-labels {
  position: absolute;
  top: 23px;
  left: 98px;
  width: 334px;
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 17px;
}

.y-labels {
  position: absolute;
  top: 78px;
  left: 30px;
  height: 306px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  color: var(--muted);
  font-size: 17px;
}

.x-axis {
  position: absolute;
  top: 46px;
  left: 74px;
  width: 419px;
  height: 3px;
  background: var(--blue);
}

.y-axis {
  position: absolute;
  top: 58px;
  left: 62px;
  width: 3px;
  height: 382px;
  background: var(--orange);
}

.x-axis::after,
.y-axis::after {
  content: "";
  position: absolute;
  width: 0;
  height: 0;
  border-style: solid;
}

.x-axis::after {
  right: -1px;
  top: -5px;
  border-width: 6px 0 6px 10px;
  border-color: transparent transparent transparent var(--blue);
}

.y-axis::after {
  left: -5px;
  bottom: -1px;
  border-width: 10px 6px 0;
  border-color: var(--orange) transparent transparent;
}

.x-axis span,
.y-axis span {
  position: absolute;
  font: 800 21px Georgia, serif;
}

.x-axis span { top: -13px; right: -28px; color: var(--blue); }
.y-axis span { left: -6px; bottom: -31px; color: var(--orange); }

.pixel-callout {
  position: absolute;
  top: 263px;
  left: 317px;
  padding: 8px 12px;
  background: var(--ink);
  color: #fff;
  font-size: 17px;
  font-weight: 750;
}

.coordinate-notes { display: grid; gap: 14px; }

.fact-card {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 16px;
  align-items: center;
  padding: 20px 22px;
  border-top: 1px solid var(--ink);
  border-inline: var(--card-edge);
  border-bottom: var(--card-edge);
  background: var(--white);
  box-shadow: var(--card-shadow);
}

.fact-card > span { color: var(--blue); font-size: 14px; font-weight: 850; }
.fact-card p { margin: 0; font-size: 23px; }

.axis-facts {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.axis-facts p {
  margin: 0;
  padding: 17px;
  border: 1px solid var(--line);
  font-size: 20px;
  text-align: center;
}

.range-box {
  padding: 19px 23px;
  border-left: 5px solid var(--orange);
  background: var(--orange-soft);
}

.range-box p { margin: 3px 0; font-size: 20px; }
.range-box small { display: block; margin-top: 8px; color: var(--muted); font-size: 14px; }

.affine-flow {
  display: grid;
  justify-items: center;
  align-content: start;
  gap: 22px;
  padding-top: 5px;
}

.formula-pair {
  display: flex;
  gap: 68px;
  font: italic 34px Georgia, "Times New Roman", serif;
}

.matrix-equation {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 22px;
  font: 30px Georgia, "Times New Roman", serif;
}

.matrix-equation.major {
  padding: 19px 62px;
  border-top: 2px solid var(--blue);
  background: var(--white);
  box-shadow: var(--card-shadow);
  font-size: 38px;
}

.homogeneous-note {
  padding: 9px 17px;
  background: var(--orange-soft);
  color: var(--ink-soft);
  font-size: 18px;
}

.homogeneous-note strong { color: var(--orange); }

.parameter-strip {
  align-self: end;
  justify-self: center;
  display: flex;
  align-items: center;
  gap: 18px;
  margin-bottom: 19px;
  color: var(--muted);
  font-size: 19px;
}

.parameter-strip span { color: var(--ink); font-weight: 780; }
.parameter-strip i { width: 5px; height: 5px; background: var(--orange); }

.row-calculation {
  display: grid;
  gap: 19px;
  align-content: center;
  padding: 10px 82px 110px;
}

.row-calculation article {
  position: relative;
  display: grid;
  grid-template-columns: 130px 1fr;
  padding: 28px 32px;
  background: var(--white);
  border-inline: var(--card-edge);
  border-bottom: var(--card-edge);
  box-shadow: var(--card-shadow);
}

.row-calculation article.x-row { border-top: 4px solid var(--blue); }
.row-calculation article.y-row { border-top: 4px solid var(--orange); }

.row-badge {
  align-self: center;
  color: var(--ink);
  font-size: 18px;
  font-weight: 800;
}

.row-expression {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
  font: 32px Georgia, "Times New Roman", serif;
}

.row-vector { padding-bottom: 7px; border-bottom: 2px solid currentColor; }
.x-row .row-vector { color: var(--blue); }
.y-row .row-vector { color: var(--orange); }
.row-expression strong { font-size: 42px; }

.row-calculation article > p {
  grid-column: 2;
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 16px;
  text-align: center;
}

.definition-note {
  position: absolute;
  left: 170px;
  right: 170px;
  bottom: 78px;
  display: flex;
  gap: 23px;
  align-items: center;
  padding: 16px 22px;
  border-left: 5px solid var(--blue);
  background: var(--blue-soft);
  font-size: 17px;
}

.definition-note strong { white-space: nowrap; color: var(--blue); }

.lab-slide { background: #f1eee7; }

.lab-layout {
  display: grid;
  grid-template-columns: .78fr 1.22fr;
  gap: 24px;
  min-height: 0;
  padding: 0 38px 73px;
}

.lab-controls,
.lab-visual {
  min-height: 0;
  margin: 0;
  background: var(--white);
  border-inline: var(--card-edge);
  border-bottom: var(--card-edge);
  box-shadow: var(--card-shadow);
}

.lab-controls {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 26px 30px;
  border-top: 4px solid var(--blue);
}

.lab-index {
  margin: 0 0 20px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: .14em;
}

.lab-matrix-row {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  min-height: 105px;
  font: 27px Georgia, "Times New Roman", serif;
}

.lab-matrix-row[data-matrix-trigger] {
  margin: -5px -8px 0;
  padding: 5px 8px 0;
  border: 1px solid transparent;
  cursor: pointer;
  transition: border-color .18s ease, background .18s ease;
}

.lab-matrix-row[data-matrix-trigger]::after {
  content: "계산 과정 보기";
  position: absolute;
  top: 4px;
  right: 7px;
  color: var(--blue);
  font: 750 11px system-ui, sans-serif;
  letter-spacing: .04em;
}

.lab-matrix-row[data-matrix-trigger]:hover {
  border-color: #c4d5ff;
  background: var(--blue-soft);
}

.lab-matrix-row[data-matrix-trigger]:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 2px;
}

.lab-matrix-row .matrix { font-size: 24px; }
.lab-matrix-row [data-cell] { color: var(--blue); font-weight: 800; }

.lab-formulas {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin: 17px 0 20px;
}

.lab-formulas p {
  margin: 0;
  padding: 14px 12px;
  background: #f0f2f7;
  font: 21px Georgia, "Times New Roman", serif;
  text-align: center;
}

.lab-parameters { display: grid; gap: 15px; }

.parameter-control {
  display: grid;
  grid-template-columns: 1fr 78px;
  gap: 9px 12px;
  align-items: center;
}

.parameter-control label {
  grid-column: 1 / -1;
  color: var(--ink-soft);
  font-size: 15px;
  font-weight: 700;
}

.parameter-control label strong { color: var(--blue); }

.parameter-control input[type="range"] {
  width: 100%;
  accent-color: var(--blue);
}

.parameter-control input[type="number"] {
  width: 78px;
  padding: 7px 8px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.lab-reset {
  align-self: start;
  margin-top: auto;
  padding: 9px 14px;
  border: 1px solid var(--ink);
  background: transparent;
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
}

.lab-reset:hover { background: var(--ink); color: #fff; }

.lab-visual {
  position: relative;
  padding: 48px 18px 18px;
  border-top: 4px solid var(--orange);
  overflow: hidden;
}

.lab-visual figcaption {
  position: absolute;
  top: 16px;
  left: 20px;
  right: 20px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  color: var(--muted);
  font-size: 13px;
}

.lab-visual figcaption span { opacity: .55; }
.lab-visual figcaption strong { color: var(--ink); }
.lab-visual figcaption i { width: 18px; height: 1px; background: var(--line); }

.lab-canvas {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--stage);
}

.lab-status {
  position: absolute;
  left: 30px;
  bottom: 28px;
  margin: 0;
  padding: 8px 12px;
  background: rgba(255,253,248,.9);
  color: var(--ink);
  font-size: 13px;
  font-weight: 750;
}

.reflection-switch {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-bottom: 8px;
}

.reflection-switch button {
  padding: 11px 8px;
  border: 1px solid var(--line);
  background: transparent;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
}

.reflection-switch button.is-selected {
  border-color: var(--blue);
  background: var(--blue);
  color: #fff;
}

.reflection-matrix { font-size: 20px !important; }

.zero-note {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 14px;
  margin-top: 20px;
  padding: 14px 15px;
  background: var(--orange-soft);
  font-size: 14px;
  line-height: 1.45;
}

.zero-note strong { color: var(--orange); }

.conclusion-layout {
  display: grid;
  grid-template-columns: .64fr 1.36fr;
  gap: 66px;
  align-items: center;
  padding: 0 44px 140px;
}

.conclusion-matrix {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 25px;
  font: 40px Georgia, "Times New Roman", serif;
}

.conclusion-matrix .matrix { font-size: 31px; }
.result-coordinates { display: grid; gap: 11px; font: italic 54px Georgia, serif; }

.conclusion-points { display: grid; gap: 12px; }

.conclusion-points p {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 14px;
  align-items: center;
  margin: 0;
  padding: 16px 18px;
  border-top: 1px solid var(--ink);
  border-inline: var(--card-edge);
  border-bottom: var(--card-edge);
  background: var(--white);
  box-shadow: var(--card-shadow);
  font-size: 19px;
  line-height: 1.35;
}

.conclusion-points .point-number {
  color: var(--blue);
  font-size: 13px;
  font-weight: 850;
}

.conclusion-points .conclusion-copy {
  color: var(--ink);
  font-size: 19px;
  font-weight: 400;
}

.references {
  position: absolute;
  left: 88px;
  right: 88px;
  bottom: 67px;
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: 3px 18px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 11px;
}

.references strong {
  grid-row: 1 / span 3;
  color: var(--ink);
}

.end-slide {
  display: block;
  padding: 0;
  background: var(--ink);
  color: var(--white);
}

.end-slide::after {
  width: 20px;
  background: var(--orange);
}

.end-image {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 58%;
}

.end-overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(23,34,59,.96) 0%, rgba(23,34,59,.9) 42%, rgba(23,34,59,.42) 72%, rgba(23,34,59,.18) 100%),
    linear-gradient(0deg, rgba(23,34,59,.45), transparent 55%);
}

.end-topline {
  position: absolute;
  top: 65px;
  left: 92px;
  right: 92px;
  display: flex;
  justify-content: space-between;
  padding-bottom: 18px;
  border-bottom: 1px solid rgba(255,255,255,.28);
  color: #d8e2fa;
  font-size: 13px;
  font-weight: 850;
  letter-spacing: .16em;
  font-variant-numeric: tabular-nums;
}

.end-content {
  position: absolute;
  top: 205px;
  left: 92px;
}

.end-kicker {
  margin: 0 0 19px;
  color: #8eb3ff;
  font-size: 15px;
  font-weight: 850;
  letter-spacing: .22em;
}

.end-content h2 {
  margin: 0;
  font-size: 94px;
  font-weight: 820;
  line-height: 1;
  letter-spacing: -.06em;
}

.end-content > p:last-child {
  margin: 27px 0 0;
  color: #c6cedd;
  font-size: 19px;
  letter-spacing: .02em;
}

.end-summary {
  position: absolute;
  left: 92px;
  right: 92px;
  bottom: 78px;
  display: grid;
  grid-template-columns: 170px 1fr auto;
  gap: 30px;
  align-items: center;
  padding: 22px 25px;
  border-top: 3px solid var(--orange);
  background: rgba(23,34,59,.82);
  backdrop-filter: blur(9px);
}

.end-summary-label {
  display: grid;
  gap: 6px;
}

.end-summary-label span {
  color: #fff;
  font-size: 20px;
  font-weight: 800;
}

.end-summary-label small {
  color: #8eb3ff;
  font-size: 10px;
  font-weight: 850;
  letter-spacing: .16em;
}

.end-summary > p {
  margin: 0;
  padding-left: 29px;
  border-left: 1px solid rgba(255,255,255,.24);
  color: #c6cedd;
  font-size: 18px;
  line-height: 1.45;
}

.end-summary > p strong { color: #fff; }

.end-mini-equation {
  display: flex;
  align-items: center;
  gap: 15px;
  color: #d8e2fa;
  font: 25px Georgia, "Times New Roman", serif;
}

.end-mini-equation .matrix { gap: 2px 10px; font-size: 18px; }

#rotate-notice {
  position: fixed;
  z-index: 1000;
  display: none;
  color: var(--white);
}

@media (orientation: portrait) and (max-width: 820px) {
  #rotate-notice {
    inset: 12px 12px auto;
    display: grid;
    gap: 5px;
    padding: 14px 16px;
    border-left: 4px solid var(--orange);
    background: rgba(23,34,59,.96);
    text-align: left;
    pointer-events: none;
  }

  #rotate-notice strong { font-size: 18px; }
  #rotate-notice span { color: #c6cedd; font-size: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: .001ms !important;
    animation-duration: .001ms !important;
  }
}