:root {
  --craie-paper: #f5f4ef;
  --craie-ink: #222222;
  --craie-accent: #222222;
  --craie-sage: #ecece6;
  --craie-clay: #e8e7e0;
  --craie-ink-soft: #4e4e4b;
  --craie-line: #c8c8c1;
  --craie-accent-hover: #444444;
  --magnet-blue: #84b8d1;
  --magnet-orange: #e6ab80;
  --magnet-green: #9dbca4;
  --font-display: "Cabin Sketch", sans-serif;
}
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 1.5rem;
  scrollbar-color: var(--craie-accent) var(--craie-paper);
}

body {
  margin: 0;
  background: var(--craie-paper);
  color: var(--craie-ink);
  font-family: var(--font-body);
  font-size: 1.125rem;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: var(--craie-ink);
  color: var(--craie-sage);
}

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.22em;
}

a:hover {
  text-decoration-thickness: 2px;
}

button {
  font: inherit;
}

a,
button {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 3px solid var(--craie-accent);
  outline-offset: 5px;
}

[hidden] {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1,
h2,
h3 {
  font-family: var(--font-display);
  font-weight: 700;
  font-synthesis: none;
  text-wrap: balance;
}

h3 {
  font-family: var(--font-body);
  font-weight: 650;
}

svg {
  display: block;
}

.arrow {
  width: 1.3em;
  height: 1.3em;
  flex: 0 0 auto;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.skip-link {
  position: absolute;
  z-index: 10;
  top: 0.75rem;
  left: 1rem;
  padding: 0.75rem 1rem;
  transform: translateY(-170%);
  background: var(--craie-ink);
  color: var(--craie-white);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header,
.section-inner,
.site-footer {
  width: min(100% - 3rem, 80rem);
  margin-inline: auto;
}

.site-header {
  min-height: 6.4rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.wordmark {
  color: var(--craie-accent);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 3.4rem;
  line-height: 1.05;
  letter-spacing: 0;
  text-decoration: none;
}

.wordmark-dot {
  color: var(--craie-ink);
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 2.1rem;
  font-size: 1rem;
}

.site-nav a {
  padding-block: 0.75rem;
  text-decoration: none;
}

.site-nav a:hover {
  color: var(--craie-accent);
  text-decoration: underline;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(0, 1fr);
}

.hero-copy {
  padding: clamp(3.5rem, 6.2vw, 6.5rem) clamp(1.5rem, 5.4vw, 6rem) 5rem;
  background: var(--craie-paper);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.hero h1 {
  font-size: clamp(3rem, 6.5vw, 5.8rem);
  line-height: 1.1;
  letter-spacing: 0;
}

.hero h1 span {
  display: block;
}

.hero h1 span:last-child {
  color: var(--craie-accent);
}

.hero-intro {
  max-width: 29ch;
  margin-top: 2rem;
  font-size: clamp(1.25rem, 1.7vw, 1.5rem);
  line-height: 1.4;
  text-wrap: pretty;
}

.button {
  min-height: 3.3rem;
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.4rem;
  padding: 0.8rem 1.15rem;
  border: 0;
  border-radius: 0.25rem;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 650;
  text-decoration: none;
  line-height: 1.3;
}

.button:hover {
  text-decoration: none;
}

.button--primary {
  border: 2px solid var(--craie-ink);
  background: transparent;
  color: var(--craie-ink);
}

.button--primary:hover {
  background: var(--craie-sage);
}

.hero-copy .button {
  margin-top: 2.5rem;
}

.hero-detail {
  margin-top: 0.8rem;
  font-size: 0.9rem;
}

.demo {
  padding: 1.5rem 0 1.75rem;
  background: transparent;
  color: var(--craie-ink);
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-width: 0;
  font-variant-numeric: tabular-nums;
}

.demo :focus-visible {
  outline-color: var(--craie-ink);
}

.demo-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}

.demo h2 {
  font-size: clamp(1.75rem, 2.7vw, 2.5rem);
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.demo-heading p {
  max-width: 15ch;
  padding-bottom: 0.1rem;
  font-size: 0.95rem;
  line-height: 1.35;
}

.demo-model {
  min-height: 10.5rem;
  display: flex;
  gap: 0.5rem;
  margin-top: 2rem;
}

.demo-part {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: relative;
  color: var(--craie-ink);
  border-radius: 0.25rem;
  border: 1px solid var(--craie-line);
}

.demo-plus {
  align-self: center;
  font-family: var(--font-display);
  font-size: 1.75rem;
}

.demo-part--ten {
  flex: 2;
  background: var(--craie-sage);
}

.demo-part--five {
  flex: 1;
  background: var(--craie-clay);
}

.demo-part-value {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.5rem, 3.8vw, 3.5rem);
  line-height: 1.1;
}

.demo-part-unit {
  font-size: 1.1rem;
}

.demo:not(.is-enhanced) .demo-part--five,
.demo:not(.is-enhanced) .demo-plus,
.demo[data-step="0"] .demo-part--five,
.demo[data-step="0"] .demo-plus,
.demo[data-step="3"] .demo-part--five,
.demo[data-step="3"] .demo-plus {
  display: none;
}

.demo-stage {
  margin-top: 1.5rem;
}

.demo-step {
  color: var(--craie-ink-soft);
  font-size: 0.85rem;
}

.demo-equation {
  margin-top: 0.45rem;
  min-height: 1.5em;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 2.8vw, 2.4rem);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.25;
  text-wrap: balance;
}

.demo-explanation {
  min-height: 3.1em;
  margin-top: 0.6rem;
  max-width: 43ch;
  font-size: 1rem;
  line-height: 1.45;
}

.demo-button {
  align-self: flex-start;
  min-width: 15rem;
  margin-top: 1rem;
  background: var(--craie-paper);
  color: var(--craie-ink);
}

.demo-button:hover {
  background: var(--craie-sage);
}

.demo-note {
  margin-top: 1.1rem;
  color: var(--craie-ink-soft);
  font-size: 0.8rem;
  line-height: 1.4;
}

.demo-fallback {
  padding-left: 1.2em;
  margin: 1.5rem 0 0;
  font-size: 1rem;
  line-height: 1.8;
}

.demo-fallback li + li {
  margin-top: 0.5rem;
}

.demo.is-changing .demo-model {
  animation: reveal-equation 280ms cubic-bezier(0.16, 1, 0.3, 1) both;
}

@keyframes reveal-equation {
  from {
    clip-path: inset(0 0 100% 0);
    transform: translateY(0.2rem);
  }
  to {
    clip-path: inset(0);
    transform: translateY(0);
  }
}

.algorythme {
  padding-block: 6rem 5.5rem;
}

.section-heading {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  align-items: start;
  gap: 3rem;
}

.section-heading h2,
.mission h2,
.roadmap h2,
.shop h2,
.tbi h2 {
  font-size: clamp(2.5rem, 4.1vw, 3.6rem);
  letter-spacing: 0;
  line-height: 1.12;
}

.section-heading h2 span {
  display: block;
}

.section-heading h2 .product-name {
  margin-bottom: 0.6rem;
  color: var(--craie-accent);
}

.section-summary {
  max-width: 45ch;
  padding-top: 0.25rem;
}

.section-summary p + p {
  margin-top: 1rem;
  color: var(--craie-ink-soft);
  font-size: 1rem;
}

.resource-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1.75rem;
  margin-top: 2.5rem;
  padding-block: 1rem;
  border-top: 1px solid var(--craie-line);
  border-bottom: 1px solid var(--craie-line);
  font-size: 1rem;
}

.resource-links a {
  min-height: 2rem;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
}

.resource-links a:first-child {
  color: var(--craie-accent);
  font-weight: 650;
}

.family-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 3rem;
  padding: 0;
  margin: 1rem 0 0;
  list-style: none;
}

.family-list li {
  border-bottom: 1px solid var(--craie-line);
}

.family-list a {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.4rem 1rem;
  height: 100%;
  padding-block: 1.5rem;
  text-decoration: none;
}

.family-list h3 {
  font-size: 1.4rem;
  line-height: 1.2;
  letter-spacing: -0.015em;
}

.family-list p {
  grid-column: 1;
  max-width: 44ch;
  color: var(--craie-ink-soft);
  font-size: 1rem;
  line-height: 1.4;
}

.family-list .arrow {
  grid-column: 2;
  grid-row: 1 / 3;
  align-self: center;
  color: var(--craie-accent);
}

.family-list a:hover h3 {
  color: var(--craie-accent);
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.mission {
  padding-top: 5rem;
}

.mission-intro {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  align-items: start;
  gap: 3rem;
}

.mission-intro > p {
  max-width: 46ch;
  padding-top: 0.25rem;
}

.mission-content {
  display: grid;
  grid-template-columns: 1.12fr 0.88fr;
  align-items: center;
  gap: 3rem;
  margin-top: 3rem;
  padding-bottom: 4.5rem;
  border-bottom: 1px solid var(--craie-line);
}

.principles {
  margin: 0;
  padding: 0;
  list-style: none;
}

.principles li + li {
  margin-top: 1.25rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--craie-line);
}

.principles h3 {
  font-size: 1.4rem;
  letter-spacing: -0.015em;
  line-height: 1.2;
}

.principles p {
  max-width: 50ch;
  margin-top: 0.5rem;
  color: var(--craie-ink-soft);
  font-size: 1rem;
}

.ten-frame {
  margin: 0;
  padding: 2rem;
  background: transparent;
}

.ten-frame-board {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--craie-ink);
  background: var(--craie-ink);
  margin-top: 2rem;
}

.frame-cell {
  display: grid;
  place-items: center;
  aspect-ratio: 1;
  background: var(--craie-paper);
  border: 0;
  padding: 0;
  font: inherit;
  color: var(--craie-ink);
  cursor: pointer;
  touch-action: manipulation;
}

.frame-token {
  width: 62%;
  aspect-ratio: 1;
  display: grid;
  place-items: center;
  color: var(--craie-ink);
  font-size: 1rem;
  font-weight: 700;
  border-radius: 50%;
  background: var(--magnet-blue);
  box-shadow: 1px 3px 4px rgb(0 0 0 / 18%), inset 0 1px 1px rgb(255 255 255 / 60%);
}

.frame-token--clay {
  background: var(--magnet-orange);
}

.ten-frame figcaption {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  margin-top: 1.25rem;
  font-size: 0.9rem;
  line-height: 1.4;
}

.ten-frame-equation {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0;
  font-variant-numeric: tabular-nums;
}

.roadmap {
  padding-block: 4.5rem;
  background: transparent;
  border-block: 1px solid var(--craie-line);
}

.roadmap .section-inner,
.shop .section-inner {
  display: grid;
  grid-template-columns: 0.82fr 1.18fr;
  align-items: start;
  gap: 4rem;
}

.roadmap-intro p {
  max-width: 31ch;
  margin-top: 1.5rem;
  font-size: 1rem;
}

.roadmap-list {
  margin: 0;
  padding-left: 1.5rem;
}

.roadmap-list li {
  padding: 1.25rem 0 1.25rem 0.5rem;
  border-bottom: 1px solid var(--craie-line);
}

.roadmap-list li:first-child {
  padding-top: 0;
}

.roadmap-list li::marker {
  font-family: var(--font-body);
  font-size: 1.1rem;
  font-weight: 650;
}

.roadmap-item-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
}

.roadmap-item-heading h3 {
  font-size: 1.4rem;
  line-height: 1.2;
  letter-spacing: -0.015em;
}

.roadmap-list p {
  max-width: 53ch;
  margin-top: 0.65rem;
  font-size: 1rem;
}

.availability {
  display: inline-flex;
  margin-top: 1.25rem;
  padding: 0.3rem 0.7rem;
  border: 1px solid currentColor;
  border-radius: 2rem;
  font-size: 0.9rem;
}

.roadmap-list .availability {
  flex: 0 0 auto;
  margin-top: 0;
  font-size: 0.8rem;
}

.availability--ready {
  background: transparent;
  color: var(--craie-ink);
  font-weight: 700;
  border-color: var(--craie-ink);
}

.shop {
  padding-block: 5.5rem;
}

.shop-copy h2 {
  max-width: 15ch;
}

.shop-copy > p:not(.availability) {
  max-width: 42ch;
  margin-top: 1.5rem;
}

.shop-copy > p + p:not(.availability) {
  margin-top: 1rem;
  color: var(--craie-ink-soft);
  font-size: 1rem;
}

.shop-figure {
  margin: 0;
}

.shop-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.shop-figure figcaption {
  margin-top: 0.8rem;
  max-width: 65ch;
  color: var(--craie-ink-soft);
  font-size: 0.9rem;
  line-height: 1.45;
}

.site-footer {
  padding-block: 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
  border-top: 1px solid var(--craie-line);
  font-size: 0.9rem;
}

.footer-brand {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.6rem 1.2rem;
}

.footer-brand .wordmark {
  font-size: 2rem;
}

@media (min-width: 1600px) {
  .hero-copy {
    padding-left: max(4rem, calc((100vw - 80rem) / 2));
  }


}

@media (max-width: 1000px) {
  .hero-copy {
    padding-inline: 2rem;
  }

  .hero h1 {
    font-size: clamp(2.8rem, 6.5vw, 5rem);
  }

  .hero-copy .button {
    gap: 0.75rem;
  }

  .demo {
    padding-inline: 0;
  }

  .demo-heading p {
    max-width: none;
  }

  .section-heading,
  .mission-intro,
  .mission-content {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

  .roadmap .section-inner,
  .shop .section-inner {
    gap: 2rem;
  }
}

@media (max-width: 740px) {
  .site-header {
    min-height: 5.5rem;
    padding-block: 1.1rem;
    align-items: stretch;
    flex-direction: column;
    gap: 0.65rem;
  }

  .wordmark {
    align-self: flex-start;
    font-size: 2.45rem;
  }

  .site-nav {
    width: 100%;
    justify-content: space-between;
    gap: 0.25rem 0.75rem;
    font-size: 0.875rem;
  }

  .hero {
    grid-template-columns: 1fr;
  }

  .hero-copy {
    padding: 3.5rem 1.5rem;
  }

  .hero h1 {
    font-size: clamp(2.8rem, 12vw, 5.5rem);
  }

  .hero-intro {
    max-width: 34ch;
    margin-top: 1.5rem;
  }

  .hero-actions {
    margin-top: 2rem;
  }

  .demo {
    padding: 1.5rem 0 1.75rem;
  }

  .demo-heading p {
    max-width: 15ch;
  }

  .demo-model {
    min-height: 9.5rem;
    margin-top: 1.5rem;
  }

  .demo-part-value {
    font-size: clamp(2rem, 9vw, 3.1rem);
  }

  .demo-equation {
    font-size: clamp(1.5rem, 5.3vw, 2.4rem);
  }

  .demo-explanation {
    min-height: 2.9em;
  }

  .demo-note {
    max-width: 50ch;
  }

  .algorythme {
    padding-block: 3.75rem;
  }

  .section-heading,
  .mission-intro,
  .mission-content {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .section-heading h2,
  .mission h2,
  .roadmap h2,
  .shop h2,
.tbi h2 {
    font-size: clamp(2.35rem, 7.5vw, 3.4rem);
  }

  .section-summary {
    max-width: 58ch;
  }

  .resource-links {
    gap: 0.5rem 1.5rem;
    margin-top: 1.75rem;
  }

  .family-list {
    grid-template-columns: 1fr;
  }

  .family-list a {
    padding-block: 1.3rem;
  }

  .mission {
    padding-top: 3.5rem;
  }

  .mission-content {
    margin-top: 2rem;
    padding-bottom: 3.5rem;
    gap: 2rem;
  }

  .ten-frame {
    width: 100%;
    max-width: 30rem;
    justify-self: center;
    padding: 1.25rem;
  }

  .roadmap,
  .shop {
    padding-block: 3.5rem;
  }

  .roadmap .section-inner,
  .shop .section-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .roadmap-intro p {
    max-width: 45ch;
    margin-top: 1rem;
  }

  .shop-copy > p:not(.availability) {
    max-width: 55ch;
  }

  .shop-figure figcaption {
    font-size: 0.85rem;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
    padding-block: 1.75rem;
  }
}

@media (max-width: 380px) {
  .site-header {
    padding-block: 1rem;
    align-items: flex-start;
    flex-direction: column;
    gap: 0.25rem;
  }

  .site-nav {
    justify-content: space-between;
    width: 100%;
  }

  .hero h1 {
    font-size: clamp(2.8rem, 12vw, 3.4rem);
  }

  .hero-copy .button {
    width: 100%;
  }

  .demo-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  .demo-heading p {
    max-width: none;
  }

  .demo-button {
    min-width: 0;
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .demo.is-changing .demo-model {
    animation: none;
  }
}


/* Landing identity: a light board, black writing, colour carried by magnets. */
.hero-actions { display:flex; flex-direction:column; align-items:flex-start; gap:1rem; margin-top:2.5rem; }
.hero-copy .hero-actions .button { margin-top:0; }
.hero-secondary, .tbi-demo-link { display:inline-flex; align-items:center; gap:.75rem; min-height:2.75rem; font-size:1rem; }
.hero .ten-frame { width:100%; max-width:none; padding:clamp(3.5rem,6.2vw,6.5rem) clamp(1.5rem,4vw,4rem) 3.5rem; align-self:center; }
.ten-frame h2 { font-size:clamp(2rem,3.5vw,3rem); line-height:1.15; letter-spacing:0; }
.frame-intro { margin-top:.7rem; font-size:1rem; }
.frame-hint { margin-top:1.25rem; font-size:1rem; }
.frame-cell:disabled { cursor:default; }
.frame-cell:focus-visible { position:relative; z-index:1; outline-offset:-4px; }
.demo h2 { line-height:1.15; letter-spacing:0; }
.demo-part::before { content:""; position:absolute; top:-.6rem; left:1rem; width:1.45rem; height:1.45rem; border-radius:50%; background:var(--magnet-blue); box-shadow:1px 3px 4px rgb(0 0 0 / 18%),inset 0 1px 1px rgb(255 255 255 / 55%); }
.demo-part--five::before { background:var(--magnet-orange); }
.demo-button { border:1px solid var(--craie-ink); }
.tbi { padding-block:4rem; border-block:1px solid var(--craie-line); }
.tbi-layout { display:grid; grid-template-columns:1fr 1fr; gap:4rem; }
.tbi-intro { margin-top:1.5rem; max-width:44ch; }
.tbi-intro + p { margin-top:1rem; max-width:48ch; font-size:1rem; }
.tbi-demo-link { margin-top:1.5rem; }
.magnet-word { display:inline-flex; gap:.2em; vertical-align:middle; margin-block:.15em; }
.magnet-word > span { display:grid; place-items:center; width:1.15em; height:1.25em; border-radius:.08em; background:var(--magnet-blue); box-shadow:1px 3px 4px rgb(0 0 0 / 18%),inset 0 1px 1px rgb(255 255 255 / 60%); }
.magnet-word > span:nth-child(2) { background:var(--magnet-orange); }
.magnet-word > span:nth-child(3) { background:var(--magnet-green); }
.tbi-principles { list-style:none; margin:0; padding:0; }
.tbi-principles li + li { margin-top:1.5rem; padding-top:1.5rem; border-top:1px solid var(--craie-line); }
.tbi-principles h3 { font-size:1.4rem; line-height:1.25; }
.tbi-principles p { margin-top:.5rem; max-width:47ch; font-size:1rem; color:var(--craie-ink-soft); }
@media (max-width:900px) {
  .hero { grid-template-columns:1fr; }
  .hero-copy { padding-bottom:1.5rem; }
  .hero .ten-frame { padding-top:1.5rem; max-width:38rem; justify-self:center; }
}
@media (max-width:740px) {
  .tbi-layout { grid-template-columns:1fr; gap:2rem; }
  .tbi { padding-block:3.5rem; }
  .tbi h2 { font-size:clamp(2.35rem,7.5vw,3.4rem); }
}