17.css

body {
    font-family: 'Anton';font-size: 22px;
    background-image: url('back2.jpg');
    margin: auto;
    margin-top: 70px;
    width: 60%; 
    padding: 10px;
    text-align: center;
}
hr {
            position: absolute;
            border: none;
            height: 10px;
            display: block;
            background: black;
            margin: 0px;
        }

        .container .btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  background-color: #555;
  color: white;
  font-size: 16px;
  padding: 12px 24px;
  border: none;
  cursor: pointer;
  border-radius: 5px;
  text-align: center;
  }


  .start {
      width: 60px;
      height: 30px;
      left-margin: 20px;
      right-margin: 10px;
      top-margin: 15px;
      bottom-margin: 20px;
  }

        .center {
          display: block;
          margin-left: auto;
          margin-right: auto;
          width: 50%;
        }
        img {
            max-width: 400px;
            max-height: 400px;
        }