Cut Corners using CSS

Question

I\'m looking to \"cut\" the top left corner of a div, like if you had folded the corner of a page down.

I\'d like to do it in pure CSS, are there any methods?

Answer 1

Another one solution: html:

  
Hello world!

css:

.background {
  position: relative;
  width: 50px;
  height: 50px;
  border-right: 150px solid lightgreen;
  border-bottom: 150px solid lightgreen;
  border-radius: 10px;
}
.background::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 0;
  border: 25px solid lightgreen;
  border-top-color: transparent;
  border-left-color: transparent;
}
.container {
  position: absolute;
  padding-left: 25px;
  padding-top: 25px;
  font-size: 38px;
  font-weight: bolder;
}

https://codepen.io/eggofevil/pen/KYaMjV