/*  * Material for MkDocs renders each diagram into a NEW div.mermaid and puts
 * the SVG inside a CLOSED Shadow DOM. External JavaScript cannot inspect that
 * SVG. The viewer therefore scales the accessible host element itself.
 * Mermaid color variables are inherited by the closed shadow tree, so the
 * diagram stays neutral while the surrounding course UI remains green.
 */

.mermaid {
  --md-mermaid-font-family: var(--md-text-font-family), sans-serif;
  --md-mermaid-label-fg-color: var(--md-default-fg-color);
  --md-mermaid-label-bg-color: var(--md-default-bg-color);
  --md-mermaid-node-fg-color: var(--md-default-fg-color--light);
  --md-mermaid-node-bg-color: var(--md-code-bg-color);
  --md-mermaid-edge-color: var(--md-default-fg-color--light);

  --md-mermaid-sequence-actor-bg-color: var(--md-code-bg-color);
  --md-mermaid-sequence-actor-border-color: var(--md-default-fg-color--lighter);
  --md-mermaid-sequence-actor-fg-color: var(--md-default-fg-color);
  --md-mermaid-sequence-actor-line-color: var(--md-default-fg-color--light);
  --md-mermaid-sequence-actorman-bg-color: var(--md-default-bg-color);
  --md-mermaid-sequence-actorman-line-color: var(--md-default-fg-color--light);
  --md-mermaid-sequence-message-line-color: var(--md-default-fg-color--light);
  --md-mermaid-sequence-message-fg-color: var(--md-default-fg-color);
  --md-mermaid-sequence-note-bg-color: var(--md-code-bg-color);
  --md-mermaid-sequence-note-border-color: var(--md-default-fg-color--lighter);
  --md-mermaid-sequence-note-fg-color: var(--md-default-fg-color);
  --md-mermaid-sequence-loop-fg-color: var(--md-default-fg-color);
  --md-mermaid-sequence-loop-bg-color: transparent;
  --md-mermaid-sequence-loop-border-color: var(--md-default-fg-color--lighter);
  --md-mermaid-sequence-label-bg-color: var(--md-default-bg-color);
  --md-mermaid-sequence-label-fg-color: var(--md-default-fg-color);
  --md-mermaid-sequence-number-bg-color: var(--md-default-fg-color--light);
  --md-mermaid-sequence-number-fg-color: var(--md-default-bg-color);
  --md-mermaid-sequence-box-bg-color: color-mix(in srgb, var(--md-code-bg-color) 86%, var(--md-default-bg-color));
  --md-mermaid-sequence-box-fg-color: var(--md-default-fg-color);
}

.opt-mermaid-frame {
  position: relative;
  margin: 1.2rem 0;
  border: 1px solid var(--md-default-fg-color--lightest);
  border-radius: .5rem;
  background: var(--md-default-bg-color);
  overflow: hidden;
}

.opt-mermaid-toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .35rem;
  min-height: 2.65rem;
  padding: .35rem .5rem;
  border-bottom: 1px solid var(--md-default-fg-color--lightest);
  background: var(--md-default-bg-color);
  position: relative;
  z-index: 2;
  user-select: none;
}

.opt-mermaid-tool {
  appearance: none;
  min-width: 2.15rem;
  height: 2rem;
  padding: 0 .55rem;
  border: 1px solid var(--opt-brand);
  border-radius: .3rem;
  background: var(--md-default-bg-color);
  color: var(--opt-brand-dark);
  font: inherit;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  transition: background-color .15s ease, border-color .15s ease, color .15s ease;
}

.opt-mermaid-tool:hover,
.opt-mermaid-tool:focus-visible {
  border-color: var(--opt-brand-dark);
  background: var(--opt-brand-dark);
  color: #fff;
}

.opt-mermaid-zoom-label {
  min-width: 3.8rem;
  text-align: center;
  font-variant-numeric: tabular-nums;
  font-size: .78rem;
  font-weight: 600;
  color: var(--md-default-fg-color);
}

.opt-mermaid-help {
  margin-left: auto;
  color: var(--md-default-fg-color--light);
  font-size: .68rem;
  white-space: nowrap;
}

.opt-mermaid-viewport {
  position: relative;
  overflow: auto;
  max-height: min(72vh, 52rem);
  min-height: 12rem;
  padding: .8rem;
  scrollbar-gutter: stable both-edges;
  overscroll-behavior: contain;
  background: var(--md-default-bg-color);
  cursor: grab;
}

.opt-mermaid-viewport.is-dragging {
  cursor: grabbing;
  user-select: none;
}

.opt-mermaid-stage {
  position: relative;
  min-width: 100%;
  min-height: 100%;
  margin: 0 auto;
}

/* Scale the Material host. Its SVG remains untouched inside the CLOSED
   shadow root. The stage carries the scaled dimensions, so native horizontal
   and vertical scrollbars work normally. */
.opt-mermaid-stage > div.mermaid {
  position: absolute;
  inset: 0 auto auto 0;
  margin: 0;
  padding: 0;
  background: transparent;
  overflow: visible;
  transform-origin: 0 0;
  will-change: transform;
}

.opt-mermaid-frame:fullscreen,
.opt-mermaid-frame.is-fullscreen {
  width: 100vw;
  height: 100vh;
  margin: 0;
  border: 0;
  border-radius: 0;
  background: var(--md-default-bg-color);
}

.opt-mermaid-frame:fullscreen .opt-mermaid-viewport,
.opt-mermaid-frame.is-fullscreen .opt-mermaid-viewport {
  height: calc(100vh - 3rem);
  max-height: none;
  min-height: 0;
}

@media (max-width: 720px) {
  .opt-mermaid-help { display: none; }
  .opt-mermaid-viewport {
    max-height: 68vh;
    min-height: 10rem;
    padding: .4rem;
  }
}