Toasts are as flexible as you need and have very little required markup. At a minimum, we require a single element to contain your “toasted” content and strongly encourage a dismiss button.
Toasts are slightly translucent, too, so they blend over whatever they might appear over. For browsers that support the backdrop-filterCSS property, we’ll also attempt to blur the elements under a toast.
For systems that generate more notifications, consider using a wrapping element so they can easily stack.
You can also get fancy with flexbox utilities to align toasts horizontally and/or vertically.