fix: ie compatibility

package.json

@@ -15,7 +15,7 @@
     "dev": "parcel ./example/dev.html --open --port 2235",
     "build:index": "rollup -c",
     "build:locale": "rollup -c rollup.locale.config.js",
-    "build:css": "sass --style=compressed --no-source-map src/style/index.scss index.css",
+    "build:css": "sass --style=compressed --no-source-map src/style/index.scss index.css && postcss index.css --use autoprefixer -o index.css",
     "build": "npm run lint && npm run test && npm run clean && npm run build:index && npm run build:css && npm run build:locale",
     "clean": "rimraf locale index.*",
     "lint": "eslint src/**/*.{js,vue}",
@@ -48,7 +48,10 @@
   },
   "devDependencies": {
     "@babel/core": "^7.5.5",
+    "@babel/plugin-transform-object-assign": "^7.2.0",
+    "@babel/plugin-transform-runtime": "^7.6.2",
     "@babel/preset-env": "^7.5.5",
+    "@babel/runtime": "^7.7.2",
     "@commitlint/cli": "^8.2.0",
     "@commitlint/config-conventional": "^8.2.0",
     "@vue/babel-helper-vue-jsx-merge-props": "^1.0.0",
@@ -56,6 +59,7 @@
     "@vue/component-compiler-utils": "^3.0.0",
     "@vue/test-utils": "^1.0.0-beta.29",
     "acorn": "^7.0.0",
+    "autoprefixer": "^9.7.1",
     "babel-core": "^7.0.0-bridge.0",
     "babel-eslint": "^10.0.2",
     "babel-helper-vue-jsx-merge-props": "^2.0.3",
@@ -77,6 +81,7 @@
     "lint-staged": "^9.4.2",
     "marked": "^0.7.0",
     "parcel-bundler": "^1.12.3",
+    "postcss-cli": "^6.1.3",
     "rimraf": "^3.0.0",
     "rollup": "^1.26.0",
     "rollup-plugin-auto-external": "^2.0.0",