如何模仿与图片相同的设计？

Question

body是flexbox，我不知道右上角和左下角的div怎么显示？

body {
  box-sizing: border-box;
  margin: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #f5f7fb;
  color: #122763;
}

main {
  display: flex;
  flex-direction: column;
  align-items: center;
}

Answer 1

*,
*::before,
*::after {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}
body {
  height: 100vh;
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  background-color: #f5f7fb;
  color: #122763;
}
/**top Right**/
main {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: absolute;
  top: 0;
  right: 0;
}
/**Bottom Left**/
main {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: absolute;
  bottom: 0;
  left: 0;
}

/**No Need to set body position to relative**/

Answer 2

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}


main {
  height: 100vh;
  width: 100%;
  background-color: #f5f7fb;
  color: #122763;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  overflow: hidden;
}

main::before {
  content: '';
  height: 40vh;
  width: 20%;
  margin-right: -9vw;
  margin-top: -18vh;
  align-self: flex-end;
  background-color: #fffad2;
  border-radius: 44%;
}

main::after {
  content: '';
  height: 40vh;
  width: 25%;
  margin-left: -14vw;
  margin-bottom: -18vh;
  align-self: flex-end;
  align-self: flex-start;
  background-color: #deecf9;
  border-radius: 50%;
}
.container {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.container > h1 {
  margin: 1%;
}
.container > p {
  margin: 0.5% 1% 1% 1%;
  font-size: large;
}
.container > button {
  font-size: medium;
  color: white;
  background-color: #4d5b9e;
  border-radius: 1rem;
  width: 95px;
  height: 45px;
  border: 0;
  margin: 2%;
  cursor: pointer;
}

如何模仿与图片相同的设计？

How to mimic same design as the picture?

html

css

flexbox