.hello {

  background-color: orangered;

  background-clip: padding-box;

  border-bottom: 40px solid;  

  border-image-source: linear-gradient(to bottom right, orangered 50%, transparent 50%);

  border-image-slice: 0 0 100% 0;

}

​

.world {

  background-color: deepskyblue;

  border-image-source: radial-gradient(closest-corner at 50% -150px, deepskyblue 100%, transparent);

  border-width: 75px;

}

​

​

​

​

​

html {

  background: #333;

  text-align: center;

}

.hello {

  display: inline-flex;

  justify-content: center;

  align-items: center;

  font: 3em sans-serif;

  color: #222;

  height: 75px;

  width: 200px;

  margin: 50px 15px;

}