fix: fixed VuePress container width

Author: NataliaTepluhina

src/.vuepress/styles/index.styl

@@ -1,7 +1,3 @@
-.theme-default-content:not(.custom) {
-  max-width 960px
-}
-
 .demo {
   font-family: sans-serif;
   border: 1px solid #eee;
@@ -11,4 +7,4 @@
   margin-bottom: 40px;
   user-select: none;
   overflow-x: auto;
-}
+}