@keyframes rotation{
0% {
transform: translate(-50%, -50%) rotate(0deg);
}
100% {
transform: translate(-50%, -50%) rotate(360deg);
}
}
*, *::before, *::after {
box-sizing: border-box;
}
div.rainbow{
width: 200px;
height: 100px;
display: inline-block;
padding: 10px;
/*border: 1px solid red;*/
position: fixed;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
z-index: 1;
}
/* 這個區塊做出四個背景色 */
div.rainbow::before{
content: "";
display: inline-block;
width: 230%;
height: 230%;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%) rotate(0deg);
/*border: 1px solid blue;*/
z-index: -2;
background-image: linear-gradient(green, green), linear-gradient(blue, blue), linear-gradient(purple, purple), linear-gradient(orange, orange);
background-size: 50% 50%;
background-position: 0% 0%, 100% 0%, 100% 100%, 0% 100%;
background-repeat: no-repeat;
}
div.rainbow::after{
content: "";
display: block;
width: calc(100% - 4px);
height: calc(100% - 4px);
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
z-index: -1;
background-color: white;
/*border: 1px solid brown;*/
}