Reset border styles in Tailwind compatibility package (#3132)

Author: HiDeoo

.changeset/dull-penguins-pump.md

@@ -0,0 +1,5 @@
+---
+'@astrojs/starlight-tailwind': patch
+---
+
+Fixes an issue where all border styles were not reset by the Starlight’s Tailwind compatibility package like in [Tailwind base styles](https://tailwindcss.com/docs/preflight#border-styles-are-reset).

packages/tailwind/__tests__/tailwind.test.ts

@@ -14,6 +14,10 @@ test('generates base and utilities CSS layers and defines default theme values',
 		"@layer theme;
 
 		@layer base {
+		  *, :after, :before {
+		    border: 0 solid;
+		  }
+
 		  html, :host {
 		    font-family: var(--font-sans);
 		  }

packages/tailwind/tailwind.css

@@ -29,6 +29,12 @@
 
 @layer base {
 	/* Restore crucial styles from Tailwind Preflight: https://tailwindcss.com/docs/preflight */
+	/* Allow adding a border to an element by just adding a border-width. (https://github.com/tailwindcss/tailwindcss/pull/116) */
+	*,
+	::after,
+	::before {
+		border: 0 solid;
+	}
 	/* Keep base font-family styles even in non-Starlight pages. */
 	html,
 	:host {