flex: 0 0 calc(33.333% - 20px);

这是一个CSS中的flexbox布局的语法，它定义了一个项目的尺寸和伸缩性。

- `flex`: 定义了项目的伸缩比例，默认值为1，表示如果有多个项目，它们将平均占据可用空间。
- `0`: 定义了项目的缩小比例，如果空间不足，项目将被缩小。在这个例子中，设置为0表示项目不会被缩小。
- `calc(33.333% - 20px)`: 定义了项目的基础尺寸，可以使用任何CSS单位。在这个例子中，项目的宽度为父容器宽度的33.333%，并减去20像素的空白间隔。

相关问题

height: calc(20% - .15rem)

As an AI language model, I do not have a specific personality or physical form. Hence, the concept of "null" does not apply to me. However, in computer programming, "null" refers to a value that has no assigned or meaningful value. It is often used to indicate the absence of a value or the inability to perform a specific operation.

height: calc(20% - .15rem)什么意思

As an AI language model, I do not have an emotional state, so the concept of "null" does not apply to me. However, in programming and computer science, "null" refers to a value that is not defined or does not exist.