/* The step-through figures.
 *
 * A story on the landing page is a column of step texts beside a sticky
 * panel. The panel holds the drawing, a caption, the controls and a table of
 * every part's state. Below 761px the panel is an ordinary block above the
 * one text that matches the current step, because a drawing tall enough to
 * read does not leave room for text under a sticky header on a phone.
 *
 * Surfaces are tinted backgrounds with hairline borders. There are no
 * shadows, no accent bars and no gradients. */

/* Story layout ------------------------------------------------------------ */

.scrolly {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(1.25rem, 3vw, 3.5rem);
  margin-top: 2rem;
  align-items: start;
}

.scrolly > * {
  min-width: 0;
}

.panel {
  scroll-margin-top: calc(var(--stick) + 8px);
  position: sticky;
  top: calc(var(--stick) + 14px);
  max-height: calc(100vh - var(--stick) - 28px);
  overflow-y: auto;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 12px 12px 10px;
  display: grid;
  gap: 8px;
}

.panel-caption {
  font-family: var(--sans);
  font-size: 0.92rem;
  line-height: 1.45;
  min-height: 2.9em;
  padding: 0 2px;
}

.panel-count {
  display: inline-block;
  min-width: 3.2em;
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
}

.panel-states {
  border-top: 1px solid var(--rule);
  padding-top: 8px;
}

/* Controls ---------------------------------------------------------------- */

.controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--sans);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  border-radius: 4px;
  padding: 0.42rem 0.75rem;
  cursor: pointer;
}

.btn:hover:not(:disabled) {
  border-color: var(--ink);
}

.btn:disabled {
  opacity: 0.4;
  cursor: default;
}

.btn-play[aria-pressed="true"] {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.icon {
  flex: none;
}

.dots {
  list-style: none;
  padding: 0;
  margin: 0 0 0 auto;
  display: flex;
  gap: 0.2rem;
}

.dot {
  all: unset;
  box-sizing: border-box;
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.dot::after {
  content: "";
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 1.5px solid var(--ink-3);
  transition: background 0.2s, border-color 0.2s, transform 0.2s;
}

.dot:hover::after {
  border-color: var(--ink);
}

.dot.is-active::after {
  background: var(--hot);
  border-color: var(--hot);
  transform: scale(1.25);
}

.dot:focus-visible {
  outline: 2px solid var(--hot);
  outline-offset: 0;
}

/* Step texts -------------------------------------------------------------- */

.step {
  min-height: 60vh;
  padding: 2.5rem 0;
  opacity: 0.5;
  transition: opacity 0.35s;
}

.step.is-active {
  opacity: 1;
}

.step:first-child {
  padding-top: 0.5rem;
}

.step h3 {
  font-size: 1.4rem;
  line-height: 1.25;
  font-weight: 600;
  margin: 0.4rem 0 0.9rem;
}

.step p + p {
  margin-top: 0.9rem;
}

.step .state,
.step .sample,
.step .failure,
.step .show-step {
  margin-top: 1.1rem;
}

.state {
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: 0 1.2rem;
  font-size: 0.93rem;
  line-height: 1.45;
  border-top: 1px solid var(--rule);
}

.state dt,
.state dd {
  margin: 0;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--rule);
}

.state dt {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--ink-3);
  padding-top: 0.62rem;
}

.sample figcaption {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--ink-3);
  margin-bottom: 0.35rem;
}

.sample pre {
  font-size: 0.75rem;
}

.failure {
  font-size: 0.93rem;
  line-height: 1.5;
  color: var(--ink-2);
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 0.6rem 0.8rem;
}

.failure strong {
  font-family: var(--sans);
  font-size: 0.8rem;
  letter-spacing: 0.02em;
}

.show-step {
  all: unset;
  display: inline-block;
  cursor: pointer;
  font-family: var(--sans);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--link);
  text-decoration: underline;
  text-underline-offset: 0.2em;
  margin-top: 1.1rem;
}

.show-step:focus-visible {
  outline: 2px solid var(--hot);
  outline-offset: 2px;
}

/* A figure inside a documentation page ------------------------------------- */

.prose .dots {
  margin: 0 0 0 auto;
  padding: 0;
}

.prose .dots li {
  margin: 0;
}

.prose .step h3 {
  font-size: 1.4rem;
  font-weight: 600;
  margin: 0.4rem 0 0.9rem;
}

.prose .step p {
  margin-top: 0;
}

.prose .step p + p {
  margin-top: 0.9rem;
}

.prose .step pre {
  margin-top: 0;
}

.embedded {
  margin: 1.8rem 0;
  display: grid;
  gap: 1.2rem;
}

.embedded .panel {
  position: static;
  max-height: none;
  overflow: visible;
}

.embedded .step {
  min-height: 0;
  opacity: 1;
  padding: 0;
}

/* The drawing --------------------------------------------------------------
 *
 * Two layouts are in the markup. The container query picks the narrow one
 * when the panel's drawing is under 400px wide. Text is HTML at a fixed pixel size, so
 * a label is 12px or 13px at every width; only the boxes scale. */

.dgm {
  container-type: inline-size;
  container-name: figure;
}

.dgm-layout {
  position: relative;
  width: 100%;
  isolation: isolate;
}

.dgm-wide {
  max-width: 620px;
  margin: 0 auto;
}

.dgm-narrow {
  display: none;
  max-width: 420px;
  margin: 0 auto;
}

@container figure (max-width: 399px) {
  .dgm-wide {
    display: none;
  }

  .dgm-narrow {
    display: block;
  }
}

.dgm-lines {
  z-index: 1;
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
}

.dl-base {
  fill: none;
  stroke: var(--rule-strong);
  stroke-width: 1.5;
}

.dl-live {
  fill: none;
  stroke: var(--hot);
  stroke-width: 2.5;
  stroke-dasharray: 7 5;
}

.dl-live-0 {
  animation: dgm-flow-0 0.8s linear infinite;
}

.dl-live-1 {
  animation: dgm-flow-1 0.8s linear infinite;
}

@keyframes dgm-flow-0 {
  to {
    stroke-dashoffset: -12;
  }
}

@keyframes dgm-flow-1 {
  to {
    stroke-dashoffset: -12;
  }
}

.dl-head {
  fill: var(--hot);
}

.dnode {
  position: absolute;
  box-sizing: border-box;
}

.dzone {
  border: 1px dashed var(--rule-strong);
  border-radius: 8px;
}

.dz-title {
  z-index: 3;
  text-shadow: 0 0 4px var(--paper), 0 0 4px var(--paper), 0 0 4px var(--paper);
  position: absolute;
  left: 10px;
  top: 4px;
  font-family: var(--sans);
  font-size: 12px;
  line-height: 16px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink-3);
}

.dzone.kind-trusted-zone {
  background: var(--trust-bg);
  border-color: var(--trust-line);
}

.dzone.kind-jail-zone {
  background: var(--jail-bg);
  border-color: var(--jail-line);
}

.dbox {
  z-index: 2;
  padding: 8px;
  border: 1px solid var(--rule-strong);
  border-radius: 6px;
  background: var(--paper);
  overflow: hidden;
  font-family: var(--sans);
  transition: background-color 0.35s, border-color 0.35s;
}

.dn-title {
  font-size: 13px;
  line-height: 17px;
  font-weight: 600;
  overflow-wrap: anywhere;
}

.dn-detail,
.dn-state {
  font-size: 12px;
  line-height: 16px;
  color: var(--ink-2);
  overflow-wrap: anywhere;
}

.dbox.kind-store {
  border-radius: 3px;
  background: var(--surface-2);
}

.dbox.kind-outside {
  border-style: dashed;
}

.dbox.kind-jailed {
  background: var(--jail-bg);
  border-color: var(--jail-line);
}

.dbox.kind-stage {
  text-align: center;
  padding: 8px 4px;
}

.dbox.tone-live {
  background: var(--hot-bg);
  border-color: var(--hot);
}

.dbox.tone-live .dn-state {
  color: var(--ink);
}

.dbox.tone-done {
  background: var(--trust-bg);
  border-color: var(--trust);
}

.dbox.tone-fault {
  background: var(--warn-bg);
  border-color: var(--warn);
  border-style: dashed;
}

.dbox.tone-fault .dn-state {
  color: var(--warn);
}

.dgm-chip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: baseline;
  font-family: var(--sans);
  font-size: 13px;
  margin: 0 0 8px;
}

.dgm-chip-label {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-3);
}

/* The table of states ------------------------------------------------------ */

.dgm-states {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 12.5px;
  line-height: 1.4;
}

.dgm-states th,
.dgm-states td {
  padding: 0.16rem 0.5rem 0.16rem 0;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
  text-align: left;
  font-size: 12.5px;
  letter-spacing: 0;
}

.dgm-states th {
  width: 36%;
  font-weight: 600;
  color: var(--ink-2);
}

.dgm-states tr:last-child th,
.dgm-states tr:last-child td {
  border-bottom: 0;
}

.dgm-states .sdot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  margin-right: 0.45rem;
  background: var(--rule-strong);
}

.dgm-states .tone-live .sdot {
  background: var(--hot);
}

.dgm-states .tone-done .sdot {
  background: var(--trust);
}

.dgm-states .tone-fault .sdot {
  background: var(--warn);
}

.dgm-states .tone-fault td {
  color: var(--warn);
}

.dgm-wire {
  margin-top: 6px;
  font-family: var(--sans);
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--ink-2);
}

.dgm-wire-label {
  font-weight: 600;
  margin-right: 0.5rem;
}

.dgm-msg {
  display: inline-block;
  margin-right: 0.9rem;
}

.dgm-wire code {
  font-size: 12px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* Reduced motion ------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  .dbox,
  .step {
    transition: none;
  }

  .dl-live-0,
  .dl-live-1 {
    animation: none;
    stroke-dasharray: none;
  }
}

/* Narrower screens ----------------------------------------------------------- */

@media (max-width: 1199px) {
  .scrolly {
    grid-template-columns: minmax(0, 3fr) minmax(0, 4fr);
    gap: 1.25rem;
  }

  .panel {
    padding: 10px 10px 8px;
  }

  .step {
    min-height: 56vh;
  }
}

@media (max-width: 760px) {
  .scrolly {
    display: flex;
    flex-direction: column;
    gap: 0;
  }

  .scrolly .panel {
    order: -1;
    position: static;
    max-height: none;
    overflow: visible;
  }

  .scrolly .step {
    display: none;
  }

  .scrolly .step.is-active {
    display: block;
    min-height: 0;
    padding: 1.4rem 0 0;
    opacity: 1;
  }

  .scrolly .step .show-step {
    display: none;
  }

  .panel-caption {
    font-size: 0.9rem;
    min-height: 0;
  }

  .dots {
    margin-left: 0;
    flex-wrap: wrap;
  }
}