body
{
background-image: url('back11.gif');
background-attachment: fixed;
color: #800000;
}
<!--
a:link {
text-decoration:underline;
color:#0000EE;
}
a:visited {
text-decoration:underline;
color:#551A8B;
}
a:hover {
text-decoration: none;
color:#008000;
position:relative;top:2px;left:2px;
}
a:active {
text-decoration:underline;
color:#FF0000;
}
-->
*,
*:before,
*:after {
  -webkit-box-sizing: inherit;
  box-sizing: inherit;
}

html {
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
  font-size: 60%;
}

.btn,
a.btn,
button.btn {
  font-size: 1.3rem;
  font-weight: 700;
  line-height: 0.5;
  position: relative;
  display: inline-block;
  padding: 1rem 1rem;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  -webkit-transition: all 0.3s;
  transition: all 0.3s;
  text-align: center;
  vertical-align: middle;
  text-decoration: none;
  letter-spacing: 0.05em;
  color: #252921;
  border-radius: 0.5rem;
}

a.btn-gradient {
  font-weight: normal;

  color: #00fcff;
  border-radius: 0;
  background-image: -webkit-gradient(
    linear,
    left top,
    right top,
    color-stop(40%, #0000ff),
    to(#a800ff)
  );
  background-image: -webkit-linear-gradient(left, #0000ff 40%, #a800ff 100%);
  background-image: linear-gradient(90deg, #0000ff 40%, #a800ff 100%);
}

a.btn-gradient:after {
  position: absolute;
  top: 0;
  left: 0;

  width: 100%;
  height: 100%;

  content: "";
  -webkit-transition: all 0.5s;
  transition: all 0.5s;

  background-image: -webkit-gradient(
    linear,
    left top,
    right top,
    from(#0000ff),
    color-stop(#a800ff),
    to(#ff00f0)
  );

  background-image: -webkit-linear-gradient(left, #0000ff, #a800ff, #ff00f0);

  background-image: linear-gradient(90deg, #0000ff, #a800ff, #ff00f0);
}

a.btn-gradient span {
  position: relative;
  z-index: 1;
}

a.btn-gradient:hover {
  color: #ffffff;
}

a.btn-gradient:hover:after {
  opacity: 0;
}

a.btn-gradient {
  border-radius: 100vh;
}