我可以将CSS背景定位到“底部减去x像素”吗？

介绍

// This two-value declarationbackground-position: center bottom// Is equivalent of this four-value declarationbackground-position: center 0px bottom 0px

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在你的情况下

因此,您可以将背景定位为“底部减去100px”：

background-position: center bottom -100px

例：

.container {  height: 190px;  padding: 1em;  margin: 0 auto 1em;  border: 1px solid #333;  text-align: center;    background-image: url('http://lorempixel.com/200/140/city/4');  background-repeat: no-repeat;  background-position: center bottom;}.plus {  background-position: center bottom 20px;}.minus {  background-position: center bottom -20px;}

    background-position:
    center bottom
    background-position:
    center bottom 20px
    background-position:
    center bottom -20px

见MDN documentation