― This CSS warning box can be used anytime you want to add a warning message or a note in your blog post & even in your blogger pages. This is my simple and humble creation for the day. This CSS warning box has a border shadow effect just for adding a little twist when someone hovers on your warning box. The installation of this CSS box is very easy. There are two ways of installing this on blogger, you can go to your Template section and Edit HTML or you can Choose Customize right beside the [...].