今天好累，我新增了圖案淡入淡出的效果:

$item-count: 3
$bg-color: null

@if $item-count == 1
  $bg-color: #e74c3c
@else if $item-count == 2
  $bg-color: #f1c40f
@else
  $bg-color: #2ecc71

@keyframes fadeInOut
  0%
    opacity: 0
  50%
    opacity: 1
  100%
    opacity: 0

.container
  display: flex
  justify-content: center
  align-items: center
  height: 100vh
  background-color: $bg-color

.item
  background-color: #fff
  padding: 20px
  color: #333
  font-size: 1.5rem
  border-radius: 8px
  margin: 10px
  opacity: 0
  animation: fadeInOut 2s infinite

明天再繼續。
加油!