add base scss file

src/assets/scss/main.scss

@@ -0,0 +1,4 @@
+html, body, #app, main {
+  height: 100%;
+  margin: 0;
+}

src/main.js

@@ -5,6 +5,7 @@ import router from './router'
 import store from './store'
 
 import App from './App'
+import '@/assets/scss/main.scss'
 
 
 Vue.use(Meta)