So erstellen Sie mehrere Grenzen mit Box Shadow in CSS

.many_borders {
  box-shadow:
    0 0 0 10px red,
    0 0 0 15px blue,
    0 0 0 20px red,
    0 0 0 25px blue;
}

/* 
	Here the fourth parameter is called the spread and it basically means after how many
	pixels the shadow should start spreading
*/
Smiling Skunk