multica/packages/views/editor/styles/mermaid.css

/* Mermaid diagrams */

/* The outer container does NOT scroll — `.mermaid-diagram-scroll` inside it
   does. That split is what keeps the toolbar pinned: when the container itself
   was the scroller, the absolutely-positioned toolbar scrolled away with wide
   diagrams and left no visible way to open or copy them. */
.rich-text-editor .mermaid-diagram {
  background: var(--muted);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 0.75rem 0;
  overflow: hidden;
  padding: 1rem;
  position: relative;
}

.rich-text-editor .mermaid-diagram-scroll {
  display: flex;
  /* Small diagrams sit centered at natural size; only oversized ones scroll.
     Upscaling a small diagram to fill the column would just coarsen it. */
  justify-content: center;
  overflow-x: auto;
  overflow-y: hidden;
  cursor: zoom-in;
  /* Dragging a diagram would otherwise start a native text selection: the
     iframe is a replaced element, so the whole diagram box gets painted with
     the selection highlight, and the drag runs on into the surrounding
     comment text. Selecting prose *through* the diagram still works — this
     only stops a selection from starting on the diagram itself. */
  user-select: none;
}

.rich-text-editor .mermaid-diagram-frame {
  border: 0;
  display: block;
  /* Natural width, never shrunk to the column: a wide diagram must keep a
     readable font size and scroll sideways instead of being squashed until the
     labels are unreadable. `flex: none` stops the flex parent from shrinking
     it; a `max-width` here would defeat the scroll entirely. */
  flex: none;
  /* The iframe cannot forward clicks to this document, so it would swallow
     the click-to-open gesture. Disabling pointer events hands wheel, click,
     and drag to the scroll container instead. */
  pointer-events: none;
}

/* Edge fades: a hint that the diagram continues past the container. Driven by
   data attributes the component sets from scroll position, so a diagram that
   fits shows no fade, and a scrolled-to-the-end one fades only on the left. */
.rich-text-editor .mermaid-diagram::before,
.rich-text-editor .mermaid-diagram::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: 2rem;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  z-index: 1;
}

.rich-text-editor .mermaid-diagram::before {
  left: 0;
  background: linear-gradient(to right, var(--muted), transparent);
}

.rich-text-editor .mermaid-diagram::after {
  right: 0;
  background: linear-gradient(to left, var(--muted), transparent);
}

.rich-text-editor .mermaid-diagram[data-overflow-start]::before,
.rich-text-editor .mermaid-diagram[data-overflow-end]::after {
  opacity: 1;
}

.rich-text-editor .mermaid-diagram-loading,
.rich-text-editor .mermaid-diagram-error p {
  color: var(--muted-foreground);
  font-size: 0.8125rem;
  margin: 0;
}

.rich-text-editor .mermaid-diagram-error-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.rich-text-editor .mermaid-diagram-error-head button {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 1.75rem;
  height: 1.75rem;
  border-radius: calc(var(--radius) - 2px);
  color: var(--muted-foreground);
  flex: none;
}

.rich-text-editor .mermaid-diagram-error-head button:hover {
  background: var(--secondary);
  color: var(--foreground);
}

.rich-text-editor .mermaid-diagram-error-detail {
  font-family: var(--font-mono, monospace);
  font-size: 0.75rem;
  margin: 0.375rem 0 0;
  white-space: pre-wrap;
  word-break: break-word;
}

/* The error state has no inner scroller, and the container clips; without its
   own overflow a long source line would be cut off with no way to read it. */
.rich-text-editor .mermaid-diagram-error pre {
  margin-bottom: 0;
  overflow-x: auto;
}

/* Mermaid toolbar — dark pill, top-right corner */
.rich-text-editor .mermaid-diagram-toolbar {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  display: flex;
  gap: 1px;
  padding: 0.25rem;
  background: color-mix(in srgb, black 75%, transparent);
  backdrop-filter: blur(8px);
  border-radius: var(--radius);
  transition: opacity 0.15s;
  z-index: 2;
}

/* Reveal-on-hover only where hovering exists. On touch there is no hover
   state to enter, so the toolbar would have been permanently invisible and
   the diagram effectively un-openable. */
@media (hover: hover) {
  .rich-text-editor .mermaid-diagram-toolbar {
    opacity: 0;
  }

  .rich-text-editor .mermaid-diagram:hover .mermaid-diagram-toolbar,
  .rich-text-editor .mermaid-diagram-toolbar:focus-within {
    opacity: 1;
  }
}

.rich-text-editor .mermaid-diagram-toolbar button {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 1.75rem;
  height: 1.75rem;
  border-radius: calc(var(--radius) - 2px);
  color: white;
  transition: background 0.15s;
}

.rich-text-editor .mermaid-diagram-toolbar button:hover {
  background: color-mix(in srgb, white 15%, transparent);
}

/* Full-screen viewer canvas. Not scoped to .rich-text-editor: the viewer is
   portaled to document.body by the Dialog and never renders inside the editor
   subtree. */
.mermaid-viewer-canvas {
  position: relative;
  width: 100%;
  /* Flex owns the height: the header is shrink-0 and the canvas takes the rest.
     `min-height: 0` is what allows it to shrink below content size instead of
     pushing the toolbar out of the dialog. */
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
  background: var(--muted);
  cursor: grab;
  /* Claim every touch gesture: browser pan/pinch would otherwise scroll or
     zoom the page underneath instead of moving the diagram. */
  touch-action: none;
  /* A pan that leaves the canvas would otherwise start a native text selection
     and highlight the toolbar text plus the whole iframe box. Done in CSS
     rather than by preventDefault-ing pointerdown, which would also suppress
     the default focus and silently kill the keyboard controls. */
  user-select: none;
  outline: none;
}

.mermaid-viewer-canvas:focus-visible {
  outline: 2px solid var(--ring);
  outline-offset: -2px;
}

.mermaid-viewer-canvas.is-panning {
  cursor: grabbing;
}

.mermaid-viewer-content {
  position: absolute;
  top: 0;
  left: 0;
  transform-origin: 0 0;
  will-change: transform;
}

/* Only discrete controls (toolbar buttons, +/-/0, arrow keys) ease between
   states. Drag and wheel/pinch set `is-animated` off so the diagram tracks the
   input exactly — easing direct manipulation reads as lag, not polish. */
.mermaid-viewer-content.is-animated {
  transition: transform 150ms ease-out;
}

@media (prefers-reduced-motion: reduce) {
  .mermaid-viewer-content.is-animated {
    transition: none;
  }
}

.mermaid-viewer-frame {
  border: 0;
  display: block;
  background: transparent;
  /* Same reason as the inline frame: interaction is owned by the canvas in
     this document, so the sandbox never has to be relaxed to allow zooming. */
  pointer-events: none;
}