:root {
  --mast-height: 4.25rem;
  --transport-height: 14.5rem;
}

body {
  overflow-x: hidden;
}

button {
  background: transparent;
  cursor: pointer;
}

button:disabled {
  cursor: default;
}

.app-shell {
  display: none;
}

.js .app-shell {
  display: block;
}

[hidden] {
  display: none !important;
}

.no-js-shell {
  display: block;
  min-height: 100vh;
  background: var(--canvas);
}

.no-js-lesson {
  padding: clamp(2rem, 6vw, 6rem);
  border-bottom: 1px solid var(--line-strong);
}

.no-js-label {
  color: var(--accent-strong);
  font: 700 0.68rem/1.2 var(--font-mono);
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.no-js-lesson h1 {
  max-width: 10ch;
  margin: 1rem 0;
  font: 700 clamp(3.5rem, 9vw, 8rem)/0.8 var(--font-display);
  letter-spacing: -0.07em;
  text-transform: uppercase;
}

.no-js-deck {
  max-width: 46rem;
  color: var(--dim);
  font-size: clamp(1.2rem, 2.4vw, 2rem);
  line-height: 1.1;
}

.no-js-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(20rem, 0.75fr);
  gap: clamp(2rem, 6vw, 6rem);
  margin-top: 3rem;
}

.no-js-grid aside {
  padding: 1.5rem;
  background: var(--surface);
}

.no-js-grid pre {
  overflow: auto;
  font: 0.78rem/1.65 var(--code-font);
  white-space: pre-wrap;
}

.course-mast {
  position: sticky;
  z-index: 60;
  top: 0;
  display: grid;
  min-height: var(--mast-height);
  grid-template-columns: minmax(13rem, 1fr) minmax(18rem, auto) minmax(13rem, 1fr);
  align-items: stretch;
  border-bottom: 1px solid var(--line-strong);
  background: var(--canvas);
}

.course-brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0 1.2rem;
  font: 700 0.84rem/1 var(--font-display);
  letter-spacing: -0.03em;
  text-transform: uppercase;
}

.course-logo {
  display: block;
  width: 1.8rem;
  height: 1.8rem;
  flex: 0 0 auto;
  background: var(--accent-strong);
  -webkit-mask: url("./logo/syntax-monument-mark.svg") center / contain no-repeat;
  mask: url("./logo/syntax-monument-mark.svg") center / contain no-repeat;
}

.course-brand small {
  display: block;
  margin-bottom: 0.2rem;
  color: var(--muted);
  font: 600 0.55rem var(--font-mono);
  letter-spacing: 0.14em;
}

.course-breadcrumb,
.mast-actions button {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.course-breadcrumb {
  display: grid;
  place-items: center;
  padding: 0.7rem 1rem;
  color: var(--dim);
  text-align: center;
}

.mast-actions {
  display: flex;
  justify-self: end;
  border-left: 1px solid var(--line);
}

.mast-actions button {
  display: flex;
  min-width: 6.5rem;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  padding: 0 1rem;
  border-left: 1px solid var(--line);
  color: var(--dim);
}

.mast-actions button:first-child {
  border-left: 0;
}

.mast-actions button:hover,
.mast-actions button[aria-pressed="true"] {
  background: var(--accent);
  color: var(--ink);
}

kbd {
  padding: 0.12rem 0.28rem;
  border: 1px solid currentColor;
  color: inherit;
  font: inherit;
}

.lesson-mode {
  min-height: calc(100svh - var(--mast-height));
}

.lesson-content {
  padding-bottom: calc(var(--transport-height) + 3rem);
  overflow: hidden;
}

.lesson-hero {
  display: grid;
  min-height: 31rem;
  grid-template-columns: minmax(0, 1.35fr) minmax(21rem, 0.65fr);
  border-bottom: 1px solid var(--line-strong);
}

.hero-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: clamp(2.5rem, 6vw, 6rem);
}

.eyebrow,
.section-index {
  color: var(--accent-strong);
  font: 700 0.68rem var(--font-mono);
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.eyebrow {
  margin-bottom: 1.2rem;
}

.lesson-hero h1 {
  max-width: 10ch;
  margin: 0;
  font: 700 clamp(4rem, 8vw, 8.5rem)/0.78 var(--font-display);
  letter-spacing: -0.075em;
  text-transform: uppercase;
  view-transition-name: current-lesson-title;
}

.lesson-deck {
  max-width: 48rem;
  margin: 1.8rem 0 0;
  color: var(--dim);
  font-size: clamp(1.2rem, 2.25vw, 2rem);
  line-height: 1.1;
}

.artifact-band {
  display: grid;
  min-width: 0;
  grid-template-rows: auto minmax(0, 1fr) auto;
  align-content: start;
  padding: clamp(1.25rem, 2.8vw, 2.5rem);
  background: var(--surface);
  color: var(--on-surface);
}

.artifact-head {
  display: flex;
  min-height: 5.2rem;
  align-items: start;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line-strong);
  font: 600 0.64rem var(--font-mono);
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.artifact-head small,
.artifact-duration span {
  display: block;
  margin-top: 0.35rem;
  color: var(--muted);
  font: inherit;
}

.artifact-duration {
  display: flex;
  align-items: end;
  gap: 0.45rem;
  text-align: right;
}

.artifact-duration strong {
  font: 500 4rem/0.78 var(--font-display);
  letter-spacing: -0.07em;
}

.artifact-band pre {
  align-self: start;
  width: 100%;
  max-width: 100%;
  margin: 1.5rem 0;
  overflow: auto;
}

.artifact-band code {
  color: var(--ink);
  font: 0.78rem/1.72 var(--code-font);
  white-space: pre-wrap;
}

.artifact-band footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line-strong);
  color: var(--muted);
  font: 600 0.6rem var(--font-mono);
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.reading-plane {
  display: grid;
  grid-template-columns: minmax(15rem, 0.34fr) minmax(0, 1fr);
  gap: clamp(2rem, 6vw, 6rem);
  padding: clamp(2.5rem, 4vw, 4rem) clamp(3rem, 6vw, 6rem);
  border-bottom: 1px solid var(--line-strong);
}

.reading-plane h2 {
  max-width: 32rem;
  margin: 0;
  line-height: 1.4;
}

.reading-copy {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-content: start;
  gap: 2rem;
}

.reading-copy p {
  margin: 0;
  padding-top: 1.2rem;
  border-top: 1px solid var(--line);
  color: var(--dim);
  font-size: 1.05rem;
}

.reading-copy p:first-child {
  grid-column: 1 / -1;
  color: var(--ink);
  font-size: 1.2rem;
}

.field-checks {
  padding: 0 clamp(1.25rem, 6vw, 6rem) clamp(3rem, 6vw, 6rem);
}

.field-checks > header {
  display: flex;
  min-height: 3.5rem;
  align-items: center;
  justify-content: space-between;
  color: var(--muted);
  font: 600 0.68rem var(--font-mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.field-check-row {
  display: grid;
  min-height: 4.25rem;
  grid-template-columns: 4rem minmax(0, 1fr) auto;
  gap: 1rem;
  align-items: center;
  border-top: 1px solid var(--line);
}

.field-check-row:last-child {
  border-bottom: 1px solid var(--line);
}

.field-check-row > span,
.field-check-row > em {
  color: var(--muted);
  font: 600 0.66rem var(--font-mono);
  font-style: normal;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.field-check-row > em {
  color: var(--accent-strong);
}

.field-check-row strong {
  font: 600 1.1rem var(--font-display);
}

.curriculum-transport {
  position: fixed;
  z-index: 40;
  inset: auto 0 0;
  display: grid;
  height: var(--transport-height);
  grid-template-rows: 2.1rem minmax(0, 1fr) 3.2rem;
  border-top: 1px solid var(--line-strong);
  background: var(--canvas);
  user-select: none;
}

.phase-scale {
  display: grid;
  grid-template-columns: 7.5rem minmax(0, 1fr) auto;
  align-items: stretch;
  border-bottom: 1px solid var(--line-strong);
}

.phase-scale > strong,
.phase-scale > span {
  display: grid;
  place-items: center start;
  padding: 0 0.9rem;
  color: var(--muted);
  font: 600 0.56rem var(--font-mono);
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.phase-scale > span {
  place-items: center end;
}

.phase-bars {
  display: flex;
  min-width: 0;
}

.phase-bar {
  min-width: 1.4rem;
  border-left: 1px solid var(--line-strong);
  color: transparent;
  font-size: 0;
}

.phase-bar.is-complete {
  background: var(--accent-through);
}

.phase-bar.is-current {
  background: var(--accent);
}

.phase-bar.is-sealed {
  border-color: var(--quiet);
}

.track-window {
  position: relative;
  overflow: hidden;
  touch-action: pan-y;
  cursor: grab;
}

.track-window.is-dragging {
  cursor: grabbing;
}

.lesson-track {
  position: absolute;
  top: 0;
  left: 50%;
  display: flex;
  height: 100%;
  will-change: transform;
  transition: transform 340ms cubic-bezier(0.22, 1, 0.36, 1);
}

.track-window.is-dragging .lesson-track {
  transition: none;
}

.lesson-clip {
  position: relative;
  display: grid;
  min-width: var(--clip-width);
  max-width: var(--clip-width);
  grid-template-rows: auto 1fr auto;
  padding: 0.82rem;
  overflow: hidden;
  border-right: 1px solid var(--line-strong);
  background: var(--canvas);
  text-align: left;
}

.lesson-clip:first-child {
  border-left: 1px solid var(--line-strong);
}

.lesson-clip small,
.lesson-clip span {
  color: var(--muted);
  font: 600 0.57rem var(--font-mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.lesson-clip strong {
  z-index: 1;
  align-self: center;
  max-width: 12rem;
  font: 650 clamp(1rem, 1.8vw, 1.4rem)/0.98 var(--font-display);
  letter-spacing: -0.035em;
}

.lesson-clip-index {
  position: absolute;
  z-index: 0;
  top: 0.3rem;
  right: 0.5rem;
  color: color-mix(in srgb, var(--ink) 12%, var(--canvas));
  font: 600 3.2rem/1 var(--font-display) !important;
  letter-spacing: -0.08em !important;
}

.lesson-clip.is-complete {
  background: var(--accent-wash);
}

.lesson-clip.is-current {
  background: var(--accent);
  color: var(--ink);
}

.lesson-clip.is-current small,
.lesson-clip.is-current span {
  color: var(--ink);
}

.lesson-clip.is-next {
  border-color: var(--accent-strong);
}

.lesson-clip.is-sealed {
  color: var(--quiet-strong);
}

.lesson-clip.is-sealed::after {
  position: absolute;
  inset: 0;
  content: "";
  border-block: 2px dashed var(--quiet);
  pointer-events: none;
}

.lesson-clip:hover:not(.is-current) {
  background: var(--panel-raised);
}

.fixed-playhead {
  position: absolute;
  z-index: 4;
  top: 2.1rem;
  bottom: 0;
  left: 50%;
  width: 1px;
  background: var(--quiet);
  pointer-events: none;
}

.fixed-playhead::after {
  position: absolute;
  top: 1.05rem;
  left: -0.35rem;
  width: 0.7rem;
  height: 0.7rem;
  content: "";
  background: var(--quiet);
  clip-path: circle(50%);
}

.fixed-playhead span {
  position: absolute;
  top: 0.18rem;
  left: 0.55rem;
  color: var(--quiet-strong);
  font: 700 0.53rem var(--font-mono);
  letter-spacing: 0.11em;
  white-space: nowrap;
  text-transform: uppercase;
}

.transport-controls {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto;
  border-top: 1px solid var(--line-strong);
}

.transport-step,
.lesson-complete,
.transport-map {
  min-width: 0;
  padding: 0 1rem;
  border-right: 1px solid var(--line-strong);
  font-family: var(--font-mono);
  text-transform: uppercase;
}

.transport-step {
  display: grid;
  grid-template-columns: auto 4rem minmax(0, 1fr);
  gap: 0.7rem;
  align-items: center;
  text-align: left;
}

.transport-step.next {
  grid-template-columns: 4rem minmax(0, 1fr) auto;
  text-align: right;
}

.transport-step span,
.lesson-complete span {
  color: var(--muted);
  font-size: 0.55rem;
  letter-spacing: 0.1em;
}

.transport-step strong,
.lesson-complete strong {
  overflow: hidden;
  font-size: 0.68rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.transport-step:hover:not(:disabled),
.transport-map:hover {
  background: var(--panel-raised);
  color: var(--ink);
}

.transport-step:disabled {
  color: var(--muted);
}

.lesson-complete {
  min-width: 13rem;
  background: var(--accent);
  color: var(--ink);
}

.lesson-complete span,
.lesson-complete strong {
  display: block;
}

.lesson-complete:hover {
  background: var(--accent-strong);
  color: var(--canvas);
}

.transport-map {
  border-right: 0;
  font-size: 0.58rem;
  letter-spacing: 0.08em;
}

::view-transition-old(root),
::view-transition-new(root) {
  animation-duration: 220ms;
  animation-timing-function: cubic-bezier(0.22, 1, 0.36, 1);
}

@media (max-width: 950px) {
  .course-mast {
    grid-template-columns: minmax(12rem, 1fr) minmax(0, 1fr) auto;
  }

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

  .artifact-band {
    min-height: 22rem;
  }

  .reading-plane {
    grid-template-columns: 1fr;
  }

  .phase-scale {
    grid-template-columns: 6rem minmax(0, 1fr);
  }

  .phase-scale > span,
  .transport-map {
    display: none;
  }

  .transport-controls {
    grid-template-columns: 1fr auto 1fr;
  }
}

@media (max-width: 700px) {
  :root {
    --mast-height: 6.25rem;
    --transport-height: 13.5rem;
  }

  .course-mast {
    grid-template-columns: minmax(0, 1fr) auto;
    grid-template-rows: 3.5rem 2.75rem;
  }

  .course-brand {
    padding-inline: 0.75rem;
  }

  .course-logo {
    width: 1.45rem;
    height: 1.45rem;
  }

  .course-breadcrumb {
    grid-row: 2;
    grid-column: 1 / -1;
    border-top: 1px solid var(--line);
    font-size: 0.55rem;
  }

  .mast-actions {
    grid-row: 1;
    grid-column: 2;
  }

  .mast-actions button {
    min-width: 5.4rem;
    padding-inline: 0.65rem;
  }

  .lesson-hero {
    min-height: 0;
  }

  .hero-copy {
    min-height: 28rem;
    padding: 2rem 1rem;
  }

  .lesson-hero h1 {
    font-size: clamp(3.5rem, 18vw, 5.8rem);
  }

  .artifact-band {
    min-height: 20rem;
    padding: 1rem;
  }

  .reading-plane {
    padding: 2.5rem 1rem;
  }

  .reading-copy {
    grid-template-columns: 1fr;
  }

  .reading-copy p:first-child {
    grid-column: 1;
  }

  .field-checks {
    padding-inline: 1rem;
  }

  .field-check-row {
    grid-template-columns: 2.5rem 1fr;
  }

  .field-check-row > em {
    grid-column: 2;
  }

  .curriculum-transport {
    grid-template-rows: 1.8rem minmax(0, 1fr) 3.4rem;
  }

  .phase-scale {
    grid-template-columns: 4.8rem minmax(0, 1fr);
  }

  .phase-scale > strong {
    padding-inline: 0.45rem;
    font-size: 0.49rem;
  }

  .lesson-clip {
    min-width: min(10.5rem, var(--clip-width));
    max-width: min(10.5rem, var(--clip-width));
    padding: 0.65rem;
  }

  .fixed-playhead {
    top: 1.8rem;
  }

  .transport-step {
    grid-template-columns: auto 1fr;
    padding-inline: 0.6rem;
  }

  .transport-step.next {
    grid-template-columns: 1fr auto;
  }

  .transport-step span {
    display: none;
  }

  .transport-step strong {
    max-width: 5rem;
    font-size: 0.56rem;
  }

  .lesson-complete {
    min-width: 9.4rem;
    padding-inline: 0.65rem;
  }

  .lesson-complete strong {
    font-size: 0.57rem;
    white-space: normal;
  }

  .no-js-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  ::view-transition-old(root),
  ::view-transition-new(root) {
    animation-duration: 0.001ms;
  }
}