我正在跟隨一個在線教程，感覺我做了和那個教書的人一樣的事情，但是看起來不是這樣。如果不明顯，我用的是Bootstrap(按鈕類- btn-light)。

body,
html {
  width: 100%;
  height: 100%;
  font-family: 'Montserrat', sans-serif;
  background: url(header.jpg) no-repeat center center fixed;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

h1 {
  color: white;
  font-size: 2.5rem;
  text-align: center;
  padding-top: 170px;
}

.btn {
  margin-top: -60px;
  position: absolute;
  top: 50%;
  left: 50%;
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
  font-weight: 1000;
  border-radius: 50px;
}

.btn-light {
  background-color: aqua;
  border-color: white;
}

.btn-light:hover {
  background-color: red;
  border-color: white;
}

.btn-xl {
  padding: 1rem 1.2rem;
}

<link  rel="stylesheet">
<link  rel="stylesheet" integrity="sha384-iYQeCzEYFbKjA/T2uDLTpkwGzCiq6soy8tYaI1GyVh/UjpbCx/TYkiZhlZB6+fzT" crossorigin="anonymous">
<h1 class="text-uppercase"><strong>The Biggest International Startup Of The Year</strong></h1>
<button class="btn btn-light btn-xl">More details</button>