[blog] Fix 404 link in base introduction

Reported in https://app.ahrefs.com/site-audit/3992793/4/data-explorer?columns=pageRating%2Curl%2Ctraffic%2ChttpCode%2Cdepth%2Ccompliant%2CincomingAllLinks%2Corigin&filterCollapsed=true&filterId=91013c8aafad4fe1f7a0ad504eccad42&issueId=c64da643-d0f4-11e7-8ed1-001e67ed4656&sorting=-pageRating

docs/pages/blog/introducing-mui-base.md

@@ -42,7 +42,7 @@ MUI Base offers two kinds of building blocks: unstyled components and hooks.
 Components are more straightforward to use of the two.
 Place a component on a page, add your own styles, and it's ready to go!
 It's important to note that you are not limited to the styling options available in Material UI.
-You can, of course, still use [MUI System](https://mui.com/system/](https://mui.com/system/getting-started/overview/), but if you prefer Emotion, Tailwind CSS, plain CSS, or any other styling engine, they are available too!
+You can, of course, still use [MUI System](https://mui.com/system/getting-started/overview/), but if you prefer Emotion, Tailwind CSS, plain CSS, or any other styling engine, they are available too!
 Check out the [Working with Tailwind CSS guide](/base/guides/working-with-tailwind-css/) for an example of using this library.
 
 In contrast to Material UI, MUI Base's components do not have any default styles.