CSS动画与背景颜色冲突

Question

我对动画相当陌生，不能弄清楚为什么这个按钮不会工作，只要我添加背景颜色或背景url。第一个管用，第二个不行。我认为，这与课后按钮设置的背景有些冲突。我只是不太了解动画，不知道为什么会有冲突。任何帮助都会很感激。谢谢!在这里输入链接描述

a.animated-button:link, a.animated-button:visited {
position: relative;
display: block;
margin: 30px auto 0;
padding: 14px 15px;
color: #fff;
font-size:14px;
font-weight: bold;
text-align: center;
text-decoration: none;
text-transform: uppercase;
overflow: hidden;
letter-spacing: .08em;
border-radius: 0;
text-shadow: 0 0 1px rgba(0, 0, 0, 0.2), 0 1px 0 rgba(0, 0, 0, 0.2);
-webkit-transition: all 1s ease;
-moz-transition: all 1s ease;
-o-transition: all 1s ease;
transition: all 1s ease;
}
a.animated-button:link:after, a.animated-button:visited:after {
content: "";
position: absolute;
height: 0%;
left: 50%;
top: 50%;
width: 150%;
z-index: -1;
-webkit-transition: all 0.75s ease 0s;
-moz-transition: all 0.75s ease 0s;
-o-transition: all 0.75s ease 0s;
transition: all 0.75s ease 0s;
}
a.animated-button:link:hover, a.animated-button:visited:hover {
color: #FFF;
text-shadow: none;
}
a.animated-button:link:hover:after, a.animated-button:visited:hover:after {
height: 450%;
}
a.animated-button:link, a.animated-button:visited {
position: relative;
display: block;
margin: 30px auto 0;
padding: 14px 15px;
color: #fff;
font-size:14px;
border-radius: 0;
font-weight: bold;
text-align: center;
text-decoration: none;
text-transform: uppercase;
overflow: hidden;
letter-spacing: .08em;
text-shadow: 0 0 1px rgba(0, 0, 0, 0.2), 0 1px 0 rgba(0, 0, 0, 0.2);
-webkit-transition: all 1s ease;
-moz-transition: all 1s ease;
-o-transition: all 1s ease;
transition: all 1s ease;
}
/* Victoria Buttons */
a.animated-button.victoria-one {
border: 2px solid #D24D57;
}
a.animated-button.victoria-one:after {
background: #D24D57;
-moz-transform: translateX(-50%) translateY(-50%) rotate(-25deg);
-ms-transform: translateX(-50%) translateY(-50%) rotate(-25deg);
-webkit-transform: translateX(-50%) translateY(-50%) rotate(-25deg);
transform: translateX(-50%) translateY(-50%) rotate(-25deg);
}

<div> <a href="#" class="animated-button victoria-one">Sign up</a> </div>
<div style="background-color:black;"> <a href="#" class="animated-button victoria-one">Sign up</a> </div>

Answer 1

put z-index:1

a.animated-button:link, a.animated-button:visited {
position: relative;
z-index:1;
display: block;
margin: 30px auto 0;
padding: 14px 15px;
color: #fff;
font-size:14px;
font-weight: bold;
text-align: center;
text-decoration: none;
text-transform: uppercase;
overflow: hidden;
letter-spacing: .08em;
border-radius: 0;
text-shadow: 0 0 1px rgba(0, 0, 0, 0.2), 0 1px 0 rgba(0, 0, 0, 0.2);
-webkit-transition: all 1s ease;
-moz-transition: all 1s ease;
-o-transition: all 1s ease;
transition: all 1s ease;
}
a.animated-button:link:after, a.animated-button:visited:after {
content: "";
position: absolute;
height: 0%;
left: 50%;
top: 50%;
width: 150%;
z-index: -1;
-webkit-transition: all 0.75s ease 0s;
-moz-transition: all 0.75s ease 0s;
-o-transition: all 0.75s ease 0s;
transition: all 0.75s ease 0s;
}
a.animated-button:link:hover, a.animated-button:visited:hover {
color: #FFF;
text-shadow: none;
}
a.animated-button:link:hover:after, a.animated-button:visited:hover:after {
height: 450%;
}
a.animated-button:link, a.animated-button:visited {
position: relative;
display: block;
margin: 30px auto 0;
padding: 14px 15px;
color: #fff;
font-size:14px;
border-radius: 0;
font-weight: bold;
text-align: center;
text-decoration: none;
text-transform: uppercase;
overflow: hidden;
letter-spacing: .08em;
text-shadow: 0 0 1px rgba(0, 0, 0, 0.2), 0 1px 0 rgba(0, 0, 0, 0.2);
-webkit-transition: all 1s ease;
-moz-transition: all 1s ease;
-o-transition: all 1s ease;
transition: all 1s ease;
}
/* Victoria Buttons */
a.animated-button.victoria-one {
border: 2px solid #D24D57;
}
a.animated-button.victoria-one:after {
background: #D24D57;
-moz-transform: translateX(-50%) translateY(-50%) rotate(-25deg);
-ms-transform: translateX(-50%) translateY(-50%) rotate(-25deg);
-webkit-transform: translateX(-50%) translateY(-50%) rotate(-25deg);
transform: translateX(-50%) translateY(-50%) rotate(-25deg);
}

<div> <a href="#" class="animated-button victoria-one">Sign up</a> </div>
<div style="background-color:black;"> <a href="#" class="animated-button victoria-one">Sign up</a> </div>