From 1d10f20b48535d732af7821195ff2c59f2d031da Mon Sep 17 00:00:00 2001
From: Adam Wathan <adam.wathan@gmail.com>
Date: Sat, 1 Jun 2019 15:51:02 -0400
Subject: [PATCH] Error when someone tries to use

---
 src/lib/substituteTailwindAtRules.js | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/lib/substituteTailwindAtRules.js b/src/lib/substituteTailwindAtRules.js
index 581ec8001..3aa181d29 100644
--- a/src/lib/substituteTailwindAtRules.js
+++ b/src/lib/substituteTailwindAtRules.js
@@ -13,6 +13,11 @@ export default function(
 ) {
   return function(css) {
     css.walkAtRules('tailwind', atRule => {
+      if (atRule.params === 'preflight') {
+        // prettier-ignore
+        throw atRule.error("`@tailwind preflight` is not a valid at-rule in Tailwind v1.0, use `@tailwind base` instead.", { word: 'preflight' })
+      }
+
       if (atRule.params === 'base') {
         atRule.before(updateSource(pluginBase, atRule.source))
         atRule.remove()