fix($core): theme/styles/index.styl doesn't work

Author: ulivz

packages/@vuepress/core/lib/internal-plugins/style/index.js

@@ -1,12 +1,12 @@
 const { fs, path, logger, chalk } = require('@vuepress/shared-utils')
 
-module.exports = (options, context) => ({
+module.exports = (options, ctx) => ({
   name: '@vuepress/internal-style',
 
   enhanceAppFiles: [path.resolve(__dirname, 'client.js')],
 
   async ready () {
-    const { sourceDir, writeTemp } = context
+    const { sourceDir, writeTemp } = ctx
 
     const overridePath = path.resolve(sourceDir, '.vuepress/override.styl')
     const hasUserOverride = fs.existsSync(overridePath)
@@ -15,10 +15,17 @@ module.exports = (options, context) => ({
       logger.tip(`${chalk.magenta('override.styl')} has been deprecated from v1.0.0, using ${chalk.cyan('.vuepress/style/palette.styl')} instead.\n`)
     }
 
-    // style.styl API.
-    const stylePath = path.resolve(sourceDir, '.vuepress/styles/index.styl')
-    const hasUserStyle = fs.existsSync(stylePath)
-    await writeTemp('style.styl', hasUserStyle ? `@import(${JSON.stringify(stylePath)})` : '')
+    const themeStyle = path.resolve(ctx.themePath, 'styles/index.styl')
+    const userStyle = path.resolve(sourceDir, '.vuepress/styles/index.styl')
+
+    const themeStyleContent = fs.existsSync(themeStyle)
+      ? `@import(${JSON.stringify(themeStyle)})`
+      : ''
+    const userStyleContent = fs.existsSync(userStyle)
+      ? `@import(${JSON.stringify(userStyle)})`
+      : ''
+
+    const styleContent = themeStyleContent + userStyleContent
+    await writeTemp('style.styl', styleContent)
   }
 })
-