position: fixed with a semi-transparent background.

• Category: CSS Questions — part of the CSS Tutorial on GoCareerGo
• Read the short summary above, then check the linked docs for full syntax/behaviour
• Interview tip: be ready to explain "How to Create a Full-Page Overlay?" in one sentence, then back it up with a tiny example

/* How to Create a Full-Page Overlay? */
.example {
  /* see the property reference on MDN for full syntax */
}