如你所愿 仪表盘页面只有一列布局，所以在customer_account_index 布局句柄，因为这是用于客户帐户仪表板布局.

As you want One column layout for Dashboard Page only, so Make your changes in customer_account_index Layout handle as this is for Customer account dashboard layout.

如果您将在 customer_account 句柄上进行更改，如果未在特定句柄上更新，它将应用于所有客户页面.

And if you will make your changes on customer_account handle it will apply on all the customer pages if not updated on particular handle.

希望对您有所帮助！！