diff --git a/packages/install-site.js b/packages/install-site.js
index 91c2b70..d3f65c1 100644
--- a/packages/install-site.js
+++ b/packages/install-site.js
@@ -1,19 +1,13 @@
 import { inject } from 'vue'
 import { Fullscreen, Screen } from './plugins'
-import { omit } from 'lodash-es'
+import { forEach, omit } from 'lodash-es'
 
 const BaseKey = Symbol('Site')
 
-const defaultPlugins = [
-    {
-        name: 'fullscreen',
-        plugin: Fullscreen
-    },
-    {
-        name: 'screen',
-        plugin: Screen
-    }
-]
+const defaultPlugins = {
+    fullscreen: Fullscreen,
+    screen: Screen
+}
 
 function install (app, options) {
     const { config: pluginConfig } = options
@@ -26,7 +20,7 @@ function install (app, options) {
     app.config.globalProperties.$site = $site
     app.provide(BaseKey, $site)
 
-    defaultPlugins.forEach(({ name, plugin }) => {
+    forEach(defaultPlugins, (plugin, name) => {
         const pluginOptions = { ...options, ...pluginConfig[name] }
         plugin.install(app, omit(pluginOptions, ['config']), $site)
         plugin.__installed = true
diff --git a/packages/plugins/screen/index.js b/packages/plugins/screen/index.js
index 8eafb8a..46bd24e 100644
--- a/packages/plugins/screen/index.js
+++ b/packages/plugins/screen/index.js
@@ -3,14 +3,13 @@ import { addClass, getWindowSize, removeClass } from '../../utils/dom'
 import { addEvt } from '../../utils/event'
 import { debounce, pick } from 'lodash-es'
 
-const SIZE_LIST = ['xs', 'sm', 'md', 'lg', 'xl', 'xxl']
+const SIZE_LIST = ['sm', 'md', 'lg', 'xl', 'xxl']
 
 export default createReactivePlugin({
     width: 0,
     height: 0,
     name: 'xs',
     sizes: {
-        xs: 0,
         sm: 576,
         md: 768,
         lg: 992,
@@ -65,10 +64,10 @@ export default createReactivePlugin({
             this.gt.xl = width >= sizes.xxl
 
             this.xs = this.lt.sm
-            this.sm = this.gt.xs === false && this.lt.md === true
-            this.md = this.gt.sm === false && this.lt.lg === true
-            this.lg = this.gt.md === false && this.lt.xl === true
-            this.xl = this.gt.lg === false && this.lt.xxl === true
+            this.sm = this.gt.xs === true && this.lt.md === true
+            this.md = this.gt.sm === true && this.lt.lg === true
+            this.lg = this.gt.md === true && this.lt.xl === true
+            this.xl = this.gt.lg === true && this.lt.xxl === true
             this.xxl = this.gt.xl
 
             const name = (this.xs === true && 'xs')