.header{
    position: fixed;
    top:0;
    left: 0;
    height: 60px;
    width: 100%;
    background-color: #00A7EA;
    box-shadow: 0 0 10px #aaaaaa;
    max-width: 1680px;
    padding: 20px 20px;
}

.header-left{
    float: left;
}

.header-center{
    float: center;
    font-family:Noto Sans JP;
}

.header-rigth{
    float: right;
}

.header-rigth a:hover{
    background-color: aqua;
}

.header-logo{
    height: 48px;
}

body {
    background-color: #c5c5c5;
    color: #000000;
    font-family: "Noto Sans JP","Open Sans", "Helvetica Neue";
}

.form-group{
    background-color: #ffffff;
    border-radius: 30px;;
    position: absolute;
    top: 100px;
    right: 0px;
    bottom: 0px;
    left: 0px;
    margin: auto;
    width: 400px;
    height: 300px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.btn {
  display: inline-block;
  max-width: 180px;
  text-align: left;
  background-color: #ffa300;
  font-size: 16px;
  color: #FFF;
  text-decoration: none;
  font-weight: bold;
  padding: 10px 18px;
  border-radius: 4px;
  border-bottom: 4px solid #d37800;
}

.btn:active {
    transform: translateY(4px);
    border-bottom: none;
}