当 flexbox 内容垂直居中时，如何修复滚动？

Question

我想要实现的是当视口比内容高时，内容应该垂直居中。当viewport不够高导致内容溢出时，parent应该提供垂直滚动条。

当我将 flexbox 内容对齐到中间并将内容设置为滚动时，它不仅会忽略内容边距，还会在顶部截断（假设视口比内容短）。有办法解决这个问题吗？

html, body {
    height: 100%;
}
body {
    display: flex;
    flex-wrap: nowrap;
    flex-direction: row;
    overflow: hidden;
}
.container {
    overflow-y: auto;
    display: flex;
    flex-wrap: nowrap;
    flex-direction: row;
    align-items: center;
}

.content {
    border: 1px solid grey;
    background-color: lightgrey;
    padding: 10px;
    margin: 10px;
    border-radius: 10px;
}

<div class="container">
    <div class="content">
        Start of the content
        <br />
        <br />
        Middle of the content
        <br />
        <br />
        End of the content
    </div>
</div>
<div class="container">
    <div class="content">
        Start of the content :(((
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        Middle of the content
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        End of the content
    </div>
</div>

Answer 1

align-items: safe center 应避免儿童开箱。

https://developer.mozilla.org/en-US/docs/Web/CSS/align-items

safe

Used alongside an alignment keyword. If the chosen keyword means that the item overflows the alignment container causing data loss, the item is instead aligned as if the alignment mode were start.

html, body {
    height: 100%;
}
body {
    display: flex;
    flex-wrap: nowrap;
    flex-direction: row;
    overflow: hidden;
}
.container {
    overflow-y: auto;
    display: flex;
    flex-wrap: nowrap;
    flex-direction: row;
    align-items: safe center;
}

.content {
    border: 1px solid grey;
    background-color: lightgrey;
    padding: 10px;
    margin: 10px;
    border-radius: 10px;
}

<div class="container">
    <div class="content">
        Start of the content
        <br />
        <br />
        Middle of the content
        <br />
        <br />
        End of the content
    </div>
</div>
<div class="container">
    <div class="content">
        Start of the content :(((
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        Middle of the content
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        End of the content
    </div>
</div>

如果您的浏览器不支持 safe/unsafe 关键字对齐，那么您可以使用自动边距：

html, body {
    height: 100%;
}
body {
    display: flex;
    flex-wrap: nowrap;
    flex-direction: row;
    overflow: hidden;
}
.container {
    overflow-y: auto;
    display: flex;
    flex-wrap: nowrap;
    flex-direction: row; 
    padding:10px 0;
}

.content {
    border: 1px solid grey;
    background-color: lightgrey;
    padding: 10px;
    margin:auto 10px;
    border-radius: 10px;
}

<div class="container">
    <div class="content">
        Start of the content
        <br />
        <br />
        Middle of the content
        <br />
        <br />
        End of the content
    </div>
</div>
<div class="container">
    <div class="content">
        Start of the content :(((
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        Middle of the content
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        <br />
        End of the content
    </div>
</div>

当 flexbox 内容垂直居中时，如何修复滚动？

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css

scroll

vertical-alignment