feat(theme): support title-less custom containers

docs/en/guide/what-is-vitepress.md

@@ -2,11 +2,9 @@
 
 VitePress is a [Static Site Generator](https://en.wikipedia.org/wiki/Static_site_generator) (SSG) designed for building fast, content-centric websites. In a nutshell, VitePress takes your source content written in [Markdown](https://en.wikipedia.org/wiki/Markdown), applies a theme to it, and generates static HTML pages that can be easily deployed anywhere.
 
-<div class="tip custom-block" style="padding-top: 8px">
-
+::: tip {.no-title}
 Just want to try it out? Skip to the [Quickstart](./getting-started).
-
-</div>
+:::
 
 ## Use Cases
 

src/client/theme-default/styles/components/custom-block.css

@@ -206,3 +206,12 @@
   font-size: var(--vp-custom-block-font-size);
   color: inherit;
 }
+
+.custom-block.no-title {
+  padding-top: 0px;
+  padding-bottom: 0px;
+}
+
+.custom-block.no-title .custom-block-title {
+  display: none;
+}