/*
 * Stepper
 *
 * Drawn in Figma as `Stepper` (1391:431) and `Stepper Step` (1391:356), from
 * this file. Built code-first, like Breadcrumb: the indicator is a circle at the
 * `lg` icon rung, the label type is Breadcrumb's, and the colours are the primary
 * and error roles every other status in the system uses.
 *
 * Status is never colour alone. `complete` draws a check and `error` an
 * exclamation, and both carry their name as visually hidden text.
 *
 * Status and current are BEM modifiers, not `[data-*]` attributes, and that is
 * load-bearing: the contrast gate keys contexts on `--modifier` classes. The
 * first draft used `[data-status]`, and the filled current indicator and every
 * error colour were silently unmeasured — no failure, no pass, just absent.
 */
.ion-stepper {
  display: flex;
  gap: var(--spacing-8);
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-family-sans);
  font-size: var(--type-body-sm);
  line-height: var(--type-body-sm-line-height);
}

/*
 * Horizontal only: an inline-size container stops sizing to its content, which
 * a vertical rail inside a flex parent needs to do.
 */
.ion-stepper--horizontal {
  container-type: inline-size;
}

.ion-stepper--vertical {
  flex-direction: column;
  gap: 0;
}

.ion-stepper__label {
  font-weight: var(--font-weight-medium);
  transition: color var(--ion-duration-base) var(--ion-ease-out);
}

.ion-stepper__step {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--spacing-8);
  min-width: 0;
  color: var(--text-secondary);
}

.ion-stepper--vertical .ion-stepper__step {
  align-items: flex-start;
  padding-bottom: var(--spacing-24);
}

.ion-stepper--horizontal .ion-stepper__step {
  flex: 1 1 0;
  align-items: flex-start;
}

.ion-stepper--horizontal .ion-stepper__step:last-child {
  flex: 0 0 auto;
}

.ion-stepper--vertical .ion-stepper__step:last-child {
  padding-bottom: 0;
}

/*
 * The connector. Drawn by CSS after every step but the last, so it is
 * decoration that never enters the accessibility tree. It turns primary once
 * the step before it is complete, which is the "how far have I got" reading.
 *
 * A border, not a background: the contrast gate reads `background-color` on a
 * `::after` as the ground for the whole step, and measured the check glyph
 * against its own connector at 1:1. It is a line, so it is drawn as one.
 */
.ion-stepper--horizontal .ion-stepper__step:not(:last-child)::after {
  content: '';
  flex: 1 1 var(--spacing-16);
  min-width: var(--spacing-16);

  /* Centred on the indicator, not on a step that may carry a description. */
  margin-top: calc((var(--icon-size-lg) - var(--border-width-thick)) / 2);
  border-top: var(--border-width-thick) solid var(--border-default);
}

.ion-stepper--vertical .ion-stepper__step:not(:last-child)::after {
  content: '';
  position: absolute;
  top: calc(var(--icon-size-lg) + var(--spacing-4));
  bottom: var(--spacing-4);

  /* Centred under the indicator. */
  inset-inline-start: calc(
    (var(--icon-size-lg) - var(--border-width-thick)) / 2
  );
  border-inline-start: var(--border-width-thick) solid var(--border-default);
}

.ion-stepper__trigger {
  display: inline-flex;
  align-items: flex-start;
  gap: var(--spacing-8);
  min-width: 0;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: var(--radius-xs);
  background: none;
  color: inherit;
  font: inherit;
  text-align: start;
  text-decoration: none;
}

a.ion-stepper__trigger,
button.ion-stepper__trigger {
  cursor: pointer;
}

a.ion-stepper__trigger:focus-visible,
button.ion-stepper__trigger:focus-visible {
  outline: var(--border-width-thick) solid var(--border-focus);
  outline-offset: 2px;
}

a.ion-stepper__trigger:hover .ion-stepper__label,
button.ion-stepper__trigger:hover .ion-stepper__label {
  color: var(--text-default);
  text-decoration: underline;
}

.ion-stepper__indicator {
  display: inline-flex;
  flex: none;
  align-items: center;
  justify-content: center;
  width: var(--icon-size-lg);
  height: var(--icon-size-lg);
  border: var(--border-width-thick) solid var(--border-strong);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-size: var(--type-caption);
  font-weight: var(--font-weight-semibold);
  line-height: var(--type-caption-line-height);
}

.ion-stepper__indicator svg {
  width: var(--icon-size-sm);
  height: var(--icon-size-sm);
}

.ion-stepper__text {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
  min-width: 0;

  /* Aligns the label's first line with the 24px indicator. */
  padding-top: var(--spacing-2);
}

.ion-stepper__description {
  color: var(--text-tertiary);
  font-size: var(--type-caption);
  line-height: var(--type-caption-line-height);
}

/* complete — a primary check in a primary ring, and a primary connector. */
.ion-stepper .ion-stepper__step--complete:not(:last-child)::after {
  border-color: var(--border-primary);
}

.ion-stepper__step--complete .ion-stepper__indicator {
  border-color: var(--border-primary);
  color: var(--icon-primary);
}

/* error — the same ring in error, with a different glyph. */
.ion-stepper__step--error {
  color: var(--text-error);
}

.ion-stepper__step--error .ion-stepper__indicator {
  border-color: var(--border-error);
  color: var(--icon-error);
}

/*
 * current — the one filled indicator on the row, so the position reads at a
 * glance. The label goes to the strongest text colour for the same reason
 * Breadcrumb's current crumb does.
 */
.ion-stepper__step--current {
  color: var(--text-default);
}

.ion-stepper__step--current .ion-stepper__indicator {
  border-color: var(--surface-primary);
  background-color: var(--surface-primary);
  color: var(--text-on-color);
}

.ion-stepper__step--current.ion-stepper__step--error {
  color: var(--text-error);
}

.ion-stepper__step--current.ion-stepper__step--error .ion-stepper__indicator {
  border-color: var(--surface-error);
  background-color: var(--surface-error);
  color: var(--text-on-color);
}

/*
 * Narrow containers: a horizontal stepper keeps every indicator and only the
 * current step's label. The other labels are hidden visually, NOT removed, so
 * "Step 2 of 5: Shipping, Completed" is still read for each of them.
 */
@container (max-width: 40rem) {
  .ion-stepper--horizontal .ion-stepper__step--current {
    flex: 0 1 auto;
  }

  .ion-stepper--horizontal
    .ion-stepper__step:not(.ion-stepper__step--current)
    .ion-stepper__text {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
  }
}

/*
 * Forced colours throw the primary fill away, which would leave the current
 * step looking like every other. A heavier ring survives, because width is
 * not a colour. (Not `Highlight` + `forced-color-adjust: none`: the contrast
 * gate flattens at-rules, and a system colour here replaced the real fill in
 * its model, so the white-on-primary pairing silently went unmeasured.)
 */
@media (forced-colors: active) {
  .ion-stepper__step--current .ion-stepper__indicator {
    border-width: var(--border-width-thicker);
  }
}