# 3.21 關於不透明度 opacity

## 不透明度 opacity

一個元素的不透明度，可以設定的值為 0 \~ 1的小數點。

* 0 代表完全透明。
* 1 代表完全不透明。
* 寫小數點的時候，零可以省略不寫，例： `0.5` 可以簡寫成 `.5` 。

範例：

{% embed url="<https://codepen.io/carlos411/pen/KKPyjaB>" %}

結果如圖：

![opacity 不透明度](/files/-Lo-YmFcteOphXtQ_88C)


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