diff --git a/README.md b/README.md
index 16712cb15..3e0742314 100644
--- a/README.md
+++ b/README.md
@@ -23,11 +23,14 @@ Diagramming and documentation costs precious developer time and gets outdated qu
 But not having diagrams or docs ruins productivity and hurts organizational learning.<br/>
 Mermaid addresses this problem by enabling users to create easily modifiable diagrams, it can also be made part of production scripts (and other pieces of code).<br/>
  <br/>
+
 Mermaid allows even non-programmers to easily create detailed diagrams through the [Mermaid Live Editor](https://mermaid-js.github.io/mermaid-live-editor/).<br/>
 [Tutorials](./docs/Tutorials.md) has video tutorials.
 Use Mermaid with your favorite applications, check out the list of [Integrations and Usages of Mermaid](./docs/integrations.md).
 
-For a more detailed introduction to Mermaid and some of its more basic uses, look to the [Beginner's Guide](./docs/n00b-overview.md) and [Usage](./docs/usage.md).
+You can also use Mermaid within [GitHub](https://github.blog/2022-02-14-include-diagrams-markdown-files-mermaid/) as well many of your other favorite applications, check out the list of [Integrations and Usages of Mermaid](./docs/integrations.md).
+
+For a more detailed introduction to Mermaid and some of its more basic uses, look to the [Beginner's Guide](./docs/n00b-overview.md), [Usage](./docs/usage.md) and [Tutorials](./docs/Tutorials.md).
 
 🌐 [CDN](https://unpkg.com/mermaid/) | 📖 [Documentation](https://mermaidjs.github.io) | 🙌 [Contribution](https://github.com/mermaid-js/mermaid/blob/develop/CONTRIBUTING.md) | 📜 [Changelog](./docs/CHANGELOG.md)
 
diff --git a/docs/integrations.md b/docs/integrations.md
index b1787c93c..8fa05f637 100644
--- a/docs/integrations.md
+++ b/docs/integrations.md
@@ -6,7 +6,10 @@ They also serve as proof of concept, for the variety of things that can be built
 
 
 ## Productivity
-
+- [GitHub](https://github.com) (**Native support**)
+  - [Using code blocks](https://github.blog/2022-02-14-include-diagrams-markdown-files-mermaid/) (**Native support**)
+  - [GitHub action: Compile mermaid to image](https://github.com/neenjaw/compile-mermaid-markdown-action)
+  - [svg-generator](https://github.com/SimonKenyonShepard/mermaidjs-github-svg-generator)
 - [GitLab](https://docs.gitlab.com/ee/user/markdown.html#diagrams-and-flowcharts) (**Native support**)
 - [Gitea](https://gitea.io) (**Native support**)
 - [Azure Devops](https://docs.microsoft.com/en-us/azure/devops/project/wiki/wiki-markdown-guidance?view=azure-devops#add-mermaid-diagrams-to-a-wiki-page) (**Native support**)
@@ -14,10 +17,6 @@ They also serve as proof of concept, for the variety of things that can be built
 - [Joplin](https://joplinapp.org) (**Native support**)
 - [Notion](https://notion.so) (**Native support**)
 - [Observable](https://observablehq.com/@observablehq/mermaid) (**Native support**)
-- [GitHub](https://github.com) (**Native support**)
-  - [GitHub action: Compile mermaid to image](https://github.com/neenjaw/compile-mermaid-markdown-action)
-  - [svg-generator](https://github.com/SimonKenyonShepard/mermaidjs-github-svg-generator)
-  - [Using code blocks](https://github.blog/2022-02-14-include-diagrams-markdown-files-mermaid/) (**Native support**)
 - [GitBook](http://gitbook.com)
   - [Mermaid Plugin](https://github.com/JozoVilcek/gitbook-plugin-mermaid)
   - [Markdown with Mermaid CLI](https://github.com/miao1007/gitbook-plugin-mermaid-cli)
diff --git a/src/config.js b/src/config.js
index a9fca15e8..7ae58cc32 100644
--- a/src/config.js
+++ b/src/config.js
@@ -27,7 +27,7 @@ export const updateCurrentConfig = (siteCfg, _directives) => {
 
   cfg = assignWithDepth(cfg, sumOfDirectives);
 
-  if (sumOfDirectives.theme) {
+  if (sumOfDirectives.theme && theme[sumOfDirectives.theme]) {
     const tmpConfigFromInitialize = assignWithDepth({}, configFromInitialize);
     const themeVariables = assignWithDepth(
       tmpConfigFromInitialize.themeVariables || {},
@@ -59,7 +59,7 @@ export const setSiteConfig = (conf) => {
   siteConfig = assignWithDepth({}, defaultConfig);
   siteConfig = assignWithDepth(siteConfig, conf);
 
-  if (conf.theme) {
+  if (conf.theme && theme[conf.theme]) {
     siteConfig.themeVariables = theme[conf.theme].getThemeVariables(conf.themeVariables);
   }