docs: fix rendering and ensure tidytree layout is applied

on-behalf-of: @Mermaid-Chart <hello@mermaidchart.com>

packages/mermaid/src/diagrams/mindmap/mindmapDb.ts

@@ -37,6 +37,7 @@ export class MindmapDB {
   private nodes: MindmapNode[] = [];
   private count = 0;
   private elements: Record<number, D3Element> = {};
+  private baseLevel?: number;
   public readonly nodeType: typeof nodeType;
 
   constructor() {
@@ -54,6 +55,7 @@ export class MindmapDB {
     this.nodes = [];
     this.count = 0;
     this.elements = {};
+    this.baseLevel = undefined;
   }
 
   public getParent(level: number): MindmapNode | null {
@@ -72,6 +74,17 @@ export class MindmapDB {
   public addNode(level: number, id: string, descr: string, type: number): void {
     log.info('addNode', level, id, descr, type);
 
+    let isRoot = false;
+
+    if (this.nodes.length === 0) {
+      this.baseLevel = level;
+      level = 0;
+      isRoot = true;
+    } else if (this.baseLevel !== undefined) {
+      level = level - this.baseLevel;
+      isRoot = false;
+    }
+
     const conf = getConfig();
     let padding = conf.mindmap?.padding ?? defaultConfig.mindmap.padding;
 
@@ -92,6 +105,7 @@ export class MindmapDB {
       children: [],
       width: conf.mindmap?.maxNodeWidth ?? defaultConfig.mindmap.maxNodeWidth,
       padding,
+      isRoot,
     };
 
     const parent = this.getParent(level);
@@ -99,7 +113,7 @@ export class MindmapDB {
       parent.children.push(node);
       this.nodes.push(node);
     } else {
-      if (this.nodes.length === 0) {
+      if (isRoot) {
         this.nodes.push(node);
       } else {
         throw new Error(
@@ -204,8 +218,7 @@ export class MindmapDB {
     // Build CSS classes for the node
     const cssClasses = ['mindmap-node'];
 
-    // Add section-specific classes
-    if (node.level === 0) {
+    if (node.isRoot === true) {
       // Root node gets special classes
       cssClasses.push('section-root', 'section--1');
     } else if (node.section !== undefined) {

packages/mermaid/src/diagrams/mindmap/mindmapTypes.ts

@@ -15,6 +15,7 @@ export interface MindmapNode {
   icon?: string;
   x?: number;
   y?: number;
+  isRoot?: boolean;
 }
 
 export type FilledMindMapNode = RequiredDeep<MindmapNode>;

packages/mermaid/src/docs/.vitepress/theme/mermaid.ts

@@ -1,7 +1,13 @@
 import mermaid, { type MermaidConfig } from 'mermaid';
 import zenuml from '../../../../../mermaid-zenuml/dist/mermaid-zenuml.core.mjs';
+import tidyTreeLayout from '../../../../../mermaid-layout-tidy-tree/dist/mermaid-layout-tidy-tree.core.mjs';
+import layouts from '../../../../../mermaid-layout-elk/dist/mermaid-layout-elk.core.mjs';
 
-const init = mermaid.registerExternalDiagrams([zenuml]);
+const init = Promise.all([
+  mermaid.registerExternalDiagrams([zenuml]),
+  mermaid.registerLayoutLoaders(layouts),
+  mermaid.registerLayoutLoaders(tidyTreeLayout),
+]);
 mermaid.registerIconPacks([
   {
     name: 'logos',