place-content

 place-content 属性是align-content 和 justify-content的简写. 使用这两个属性的值可以用于任何的布局情况。

/* Positional alignment */
/* align-content does not take left and right values */
place-content: center start;
place-content: start center;
place-content: end left;
place-content: flex-start center;
place-content: flex-end center;

/* Baseline alignment */
/* justify-content does not take baseline values */
place-content: baseline center;
place-content: first baseline space-evenly;
place-content: last baseline right;

/* Distributed alignment */
place-content: space-between space-evenly;
place-content: space-around space-evenly;
place-content: space-evenly stretch;
place-content: stretch space-evenly;

/* Global values */
place-content: inherit;
place-content: initial;
place-content: unset;

第一个值为 align-content 属性, 第二个值为 justify-content .

start

所有的子元素堆叠在父元素上合适的轴线上的起点对齐。

end

所有的子元素堆叠在父元素上合适的轴线上的终点对齐

flex-start

所有的子元素堆叠在父元素的主轴或交叉轴上起点对齐，主要取决于flex-direction的设置。
仅适用于flex布局的子元素.。如果父元素没有设置为flex，flex-start将被视为start

flex-end

所有的子元素堆叠在父元素的主轴或交叉轴上终点对齐，主要取决于flex-direction的设置。
仅适用于flex布局的子元素.。如果父元素没有设置为flex，flex-end将被视为end

center

所有的子元素堆叠在父元素的中间对齐

left

The items are packed flush to each other toward the left edge of the alignment container. If the property’s axis is not parallel with the inline axis, this value behaves like start.

right

The items are packed flush to each other toward the right edge of the alignment container in the appropriate axis. If the property’s axis is not parallel with the inline axis, this value behaves like start.

space-between

The items are evenly distributed within the alignment container. The spacing between each pair of adjacent items is the same. The first item is flush with the main-start edge, and the last item is flush with the main-end edge.

baseline
first baseline
last baseline

Specifies participation in first- or last-baseline alignment: aligns the alignment baseline of the box’s first or last baseline set with the corresponding baseline in the shared first or last baseline set of all the boxes in its baseline-sharing group.
The fallback alignment for first baseline is start, the one for last baseline is end.

space-around

The items are evenly distributed within the alignment container. The spacing between each pair of adjacent items is the same. The empty space before the first and after the last item equals half of the space between each pair of adjacent items.

space-evenly

The items are evenly distributed within the alignment container. The spacing between each pair of adjacent items, the main-start edge and the first item, and the main-end edge and the last item, are all exactly the same.

stretch

If the combined size of the items is less than the size of the alignment container, any auto-sized items have their size increased equally (not proportionally), while still respecting the constraints imposed by max-height/max-width (or equivalent functionality), so that the combined size exactly fills the alignment container

<'align-content'> <'justify-content'>?

#container {
  display: flex;
  height:240px;
  width: 240px;
  flex-wrap: wrap;
  background-color: #8c8c8c;
  writing-mode: horizontal-tb; /* Can be changed in the live sample */
  direction: ltr; /* Can be changed in the live sample */
  place-content: flex-end center; /* Can be changed in the live sample */
}

div > div {
  border: 2px solid #8c8c8c;
  width: 50px;
  background-color: #a0c8ff;
}

.small {
  font-size: 12px;
  height: 40px;
}

.large {
  font-size: 14px;
  height: 50px;
}

<div id="container">
  <div class="small">Lorem</div>
  <div class="small">Lorem<br/>ipsum</div>
  <div class="large">Lorem</div>
  <div class="large">Lorem<br/>impsum</div>
  <div class="large"></div>
  <div class="large"></div>
</div>

• CSS Flexbox Guide: Basic Concepts of Flexbox
• CSS Flexbox Guide: Aligning items in a flex container
• CSS Grid Guide: Box alignment in CSS Grid layouts
• CSS Box Alignment
• The align-content property
• The justify-content property