CSS框/阴影重叠问题z-index [英] CSS Box/shadow overlapping issue z-index

问题描述

请参阅以下代码段： http://codepen.io/anon/pen/JItLa

我试图在一行中显示不同数量项目的2行块。
悬停事件应该显示CSS阴影，但有一个问题：阴影的右边界与下一个块重叠。
你会说这里可能的解决方案是使用display：inline-block，它留下块之间的间隙，但我不需要间隙。

  html，body {margin ：0; padding：0} .wrapper {width：100％; margin-top：20px} .tile，.tile2 {float：left;背景：＃f2f2f2} .tile {width：25％}。tile2 {width：33.3％; border-left：1px solid #ddd} .tile：hover，.tile2：hover {-webkit-box-shadow：0 0 2px rgba（255，255，190，.75），0 0 23px 1px＃000; -moz-box-shadow：0 0 2px rgba（255，255，190，.75），0 0 23px 1px＃000; box-shadow：0 0 2px rgba（255，255，190，.75），0 0 23px 1px＃000} .header {padding：20px 0px 10px; text-align：center} .clear {clear：both}  

 < div class =wrapper> < div class =tile> < div class =header>一些文字< / div> < / div> < div class =tile> < div class =header>一些文字< / div> < / div> < div class =tile> < div class =header>一些文字< / div> < / div> < div class =tile> < div class =header>一些文字< / div> < / div> < div class =clear>< / div>< / div>< div class =wrapper> < div class =tile2> < div class =header>一些文字< / div> < / div> < div class =tile2> < div class =header>一些文字< / div> < / div> < div class =tile2> < div class =header>一些文字< / div> < / div> < div class =clear>< / div>< / div>  

这是怎么可能的？

这里还有一个问题：当我在块之间添加边框时，最后一个块移动到下一行不行。请参阅上述示例中的第2行。

解决方案

添加 z-index 此外，元素还必须按 z-index 因此，也要添加 position：relative 。

9.9.1指定堆栈级别：'z-index'属性

每个方块都有三维空间位置。除了它们的水平和垂直位置，盒子沿着z轴放置，并且一个在另一个的顶部格式化。当箱子在视觉上重叠时，Z轴位置特别相关。本节讨论如何沿z轴放置框。

更新Codepen - 现在可以正常工作。

  .tile：hover，.tile2：hover {
 z-index：1; 
 position：relative; 
} 
  

为了解决您的第二个问题，元素出现在一个新行，宽度不会相加，因为边框会减少 1px 。

33.3％ + + 33.3％ / code>！= 100％

您有几个不同的选项：




• 使用从< - c $ c>减去 1px width：calc（33.3％ - 1px）




• 更改框模型以在元素宽度计算中包含边框< > 盒尺寸

如果您选择使用 盒尺寸 ，如果您需要在所有浏览器上支持，则需要相应的供应商/前端。我会使用像：

  .tile2 {
 width：33.3％; 
 border-left：1px solid #ddd; 
 box-sizing：border-box; 
 -webkit-box-sizing：border-box; 
 -moz-box-sizing：border-box; 
} 
  

更新后的Codepen 。 box-sizing 。

Please take a look at the code snippet: http://codepen.io/anon/pen/JItLa

I'm trying to show 2 rows of blocks with different amount of items in a row. The hover event should reveal the CSS shadow, but there is a problem: the right border of the shadow is overlapped with the next block. You would say the possible solution here is to use display:inline-block which leaves the gaps between the blocks, but I don't need the gaps. The blocks should stay sticky to each other but the right shadow should overlap the next block onhover.

html,
body {
  margin: 0;
  padding: 0
}
.wrapper {
  width: 100%;
  margin-top: 20px
}
.tile,
.tile2 {
  float: left;
  background: #f2f2f2
}
.tile {
  width: 25%
}
.tile2 {
  width: 33.3%;
  border-left: 1px solid #ddd
}
.tile:hover,
.tile2:hover {
  -webkit-box-shadow: 0 0 2px rgba(255, 255, 190, .75), 0 0 23px 1px #000;
  -moz-box-shadow: 0 0 2px rgba(255, 255, 190, .75), 0 0 23px 1px #000;
  box-shadow: 0 0 2px rgba(255, 255, 190, .75), 0 0 23px 1px #000
}
.header {
  padding: 20px 0px 10px;
  text-align: center
}
.clear {
  clear: both
}

<div class="wrapper">
  <div class="tile">
    <div class="header">some text</div>
  </div>
  <div class="tile">
    <div class="header">some text</div>
  </div>
  <div class="tile">
    <div class="header">some text</div>
  </div>
  <div class="tile">
    <div class="header">some text</div>
  </div>
  <div class="clear"></div>
</div>
<div class="wrapper">
  <div class="tile2">
    <div class="header">some text</div>
  </div>
  <div class="tile2">
    <div class="header">some text</div>
  </div>
  <div class="tile2">
    <div class="header">some text</div>
  </div>
  <div class="clear"></div>
</div>

How is that possible?

There is another problem here: when I add the border between the blocks the last blocks moves to the next line which is not OK. See the 2nd row in the example given above.

解决方案

Add a z-index to the element on hover.

Additionally, the element also has to be positioned in order for the z-index property to work. Therefore add position:relative too.

9.9.1 Specifying the stack level: the 'z-index' property

z-index: Applies to: positioned elements

Each box has a position in three dimensions. In addition to their horizontal and vertical positions, boxes lie along a "z-axis" and are formatted one on top of the other. Z-axis positions are particularly relevant when boxes overlap visually. This section discusses how boxes may be positioned along the z-axis.

Updated Codepen - it works now.

.tile:hover, .tile2:hover {
    z-index: 1;
    position: relative;
}

To address your second issue, the elements are appearing on a new line because their widths do not add up, as it is 1px off due to the border.

33.3% + 33.3% + 33.3% + 1px != 100%

You have a few different options:

• Use calc() to subtract 1px from the width - width: calc(33.3% - 1px)

• Change the box model to include the border in the element's width calculation - box-sizing

If you choose to use box-sizing, you need appropriate vendors/prexes if you want support across all browsers. I would use something like:

.tile2 {
    width: 33.3%;
    border-left: 1px solid #ddd;
    box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
}

Updated Codepen using box-sizing.

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