宽度和高度 100% 不适用于弹出图像

Question

我有一个与我联系的按钮，但是，每当有人将鼠标悬停在该按钮上时，我希望出现一个全屏图像背景。但是，此图像不是全屏的。

a {
  text-decoration: none;
  color: white;
  /*Let's Chat colour*/
}

.Oval {
  position: relative;
  font-family: 'Open Sans', sans-serif;
  top: 510px;
  text-align: center;
  font-size: 25px;
  text-color: white;
  left: 30%;
  z-index: 75;
  background-color: orange;
  width: 140px;
  height: auto;
  background: #162129;
  border-radius: 40px;
  padding: 0px;
  text-decoration: none;
}

.Oval:hover {
  position: relative;
}

.Oval:hover:after {
  content: url(Lightning1.JPG);
  display: block;
  position: absolute;
  center: 100%;
  top: -510px;
  opacity: 0.5;
  z-index: -10;
  height: 100%;
  width: 100%;
}

<div class="Oval"><a href="mailto:">Let's Chat</a></div>

Answer 1

您需要在.Oval:hover:after 上添加pointer-events: none;+z-index: -1; 属性，类似于下面的sn-p。

希望下面的sn-p能帮到你。

a {
  text-decoration: none;
  color: white;
}
.Oval {
  position: relative;
  font-family: 'Open Sans', sans-serif;
  top: 100px;
  text-align: center;
  font-size: 25px;
  color: white;
  left: 50%;
  margin-left: -70px;
  background-color: orange;
  width: 140px;
  height: auto;
  background: #162129;
  border-radius: 40px;
  padding: 0px;
  text-decoration: none;
}
.Oval:hover:after {
  content:'';
  background: url(https://i.imgur.com/QgfTfOU.jpg);
  background-size: cover;
  display: block;
  position: fixed;
  top: 0;
  left: 0;
  z-index: -1;
  height: 100%;
  width: 100%;
  pointer-events: none;
}

<div class="Oval"><a href="mailto:">Let's Chat</a></div>

Answer 2

CSS 属性position:absolute 确切地说：

相对于其最近的祖先定位

1. 如果你想让背景图片占据所有屏幕空间， 那么它可以通过CSS属性position:fixed来实现 使用它，您可以将其放置在相对于视口的位置。 然后将顶部、底部、左侧、右侧值精确到0 以获得 元素到所有视口。

例如：

a {
  text-decoration: none;
  color: white;
  /*Let's Chat colour*/
}

.Oval {
  position: relative;
  font-family: 'Open Sans', sans-serif;
  top: 510px;
  text-align: center;
  font-size: 25px;
  text-color: white;
  left: 30%;
  z-index: 75;
  background-color: orange;
  width: 140px;
  height: auto;
  background: #162129;
  border-radius: 40px;
  padding: 0px;
  text-decoration: none;
}

.Oval:hover {
  position: relative;
}

/* Original
.Oval:hover:after {
  content: url(Lightning1.JPG);
  display: block;
  position: absolute;
  center: 100%;
  top: -510px;
  opacity: 0.5;
  z-index: -10;
  height: 100%;
  width: 100%;
}
*/

.Oval:hover::after {

    content: url(https://i.imgur.com/QgfTfOU.jpg);
    display: block;
    position: fixed;
    opacity: 0.5;
    z-index: -10;
    top: 0;
    border: 0;
    left: 0;
    right: 0;

}

<div class="Oval"><a href="mailto:">Let's Chat</a></div>

---

---

1. 如果你只想在div.Oval上使用背景图片，那么你应该使用CSS属性position:absolute

a {
  text-decoration: none;
  color: white;
  /*Let's Chat colour*/
}

.Oval {
  position: relative;
  font-family: 'Open Sans', sans-serif;
  top: 510px;
  text-align: center;
  font-size: 25px;
  text-color: white;
  left: 30%;
  z-index: 75;
  background-color: orange;
  width: 140px;
  height: auto;
  background: #162129;
  border-radius: 40px;
  padding: 0px;
  text-decoration: none;
  clip-path: border-box; /* Added */
  overflow: hidden; /* Added */
}

/* Original
.Oval:hover {
  position: relative;
}
*/

/* Original
.Oval:hover:after {
  content: url(Lightning1.JPG);
  display: block;
  position: absolute;
  center: 100%;
  top: -510px;
  opacity: 0.5;
  z-index: -10;
  height: 100%;
  width: 100%;
}
*/

/* Added */
.Oval:hover::after {
  content: '';
  background: url(https://i.imgur.com/QgfTfOU.jpg);
  background-size: auto;
  background-size: cover;
  display: block;
  position: absolute;
  opacity: 0.5;
  z-index: -10;
  top: 0;
  border: 0;
  left: 0;
  right: 0;
  bottom: 0;
}

<div class="Oval"><a href="mailto:">Let's Chat</a></div>

Answer 3

a {
  text-decoration: none;
  color: white;
  /*Let's Chat colour*/
}

.Oval {
  position: relative;
  font-family: 'Open Sans', sans-serif;
  top: 510px;
  text-align: center;
  font-size: 25px;
  text-color: white;
  left: 30%;
  z-index: 75;
  background-color: orange;
  width: 140px;
  height: auto;
  background: #162129;
  border-radius: 40px;
  padding: 0px;
  text-decoration: none;
}

.Oval:hover {
  position: inherit;
  left:0;
}
.Oval:hover a{display:none;}

.Oval:hover:after {
  content:'';
  background: url(https://i.imgur.com/QgfTfOU.jpg);
  background-size:cover;
  display: block;
  position: absolute;
  center: 100%;
  top:0;
  left:0;
  opacity: 0.5;
  z-index: 1;
  height: 100%;
  width: 100%;
}

<div class="Oval"><a href="mailto:">Let's Chat</a></div>