.wpcf7 {
  max-width: 600px;
  margin: 0 auto;
}

.wpcf7-form {
  padding: 1.5rem;
}

.wpcf7 label, .wpcf7 input, .wpcf7 textarea {
  font-size: 16px;
}

.wpcf7 label {
  font-weight: bold;
  color: #545454;
}

.wpcf7 input, .wpcf7 textarea {
  width: 100%;
  -webkit-appearance: none;
          appearance: none;
  border-radius: 8px;
  border: 3px solid #81ccd4;
  padding: 12px;
  color: #545454;
  font-family:'ヒラギノ角ゴ Pro W3','Hiragino Kaku Gothic Pro','メイリオ',Meiryo,'ＭＳ Ｐゴシック',sans-serif;
}

.wpcf7 input[type="submit"] {
  max-width: 200px;
  margin: 0 auto;
  display: block;
  background: #81ccd4;
  transition-property: all;
  transition: 0.2s ease-in;
}

.wpcf7 input[type="submit"]:hover {
  background: #2a9ba7;
  border-color: #2a9ba7;
  color: #fff;
}

span{
color:red;
}

.back{
margin: 0 auto;
width:100px;
}