.left {
  float: left;
  width: 45%;
}
.right {
  float: right;
  width: 45%;
}

h1 {
  text-align: left;
  padding: 0.2em;
  color: white;
  font-family: "Roboto", sans-serif;
  background-color: #4CAF50;
}
.next_button {
  float: right;
  background: #4CAF50;
}
.previous_button {
  float: left;
  background: #FF0000;
}
.previous_button:hover,.previous_button:active,.previous_button:focus {
  background: #cc0000;
}
.next_button:hover,.next_button:active,.next_button:focus {
  background: #43A047;
}

.home_page {
  width: 900px;
  margin: auto;
  display: flex;
}
.form {
  position: relative;
  background: #FFFFFF;
  min-width: 250px;
  max-width: 900px;
  margin: 0 auto 100px;
  padding: 45px;
  box-shadow: 0 0 20px 0 rgba(0, 0, 0, 0.2), 0 5px 5px 0 rgba(0, 0, 0, 0.24);
  display: none;
  
}
.challengeRequired, .challengeRequired_list {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 49%;
  border: 0;
  margin: 0;/*  0 15px; */
  padding: 10px;
  box-sizing: border-box;
  font-size: 14px;
  border-bottom: 3px solid #ff0000;
}

.challenge, .challenge_list {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 49%;
  border: 0;
  margin: 0;/*  0 15px; */
  padding: 10px;
  box-sizing: border-box;
  font-size: 14px;
}
.res_forma {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 32%;
  border: 0;
  margin: 0;/*  0 15px; */
  padding: 10px;
  box-sizing: border-box;
  font-size: 14px;
}
.notRequired {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 100%;
  border: 0;
  margin: 0 0 15px;
  padding: 15px;
  box-sizing: border-box;
  font-size: 14px;
}
.radio_select {
  margin-bottom: 15px;
  width: 100%;
}
select {
  width: 100%;
}
.radio_required {
  font-family: "Roboto", sans-serif;
  display: inline-block;
  padding-left: 0px;
  padding-right: 0px;
  box-sizing: border-box;
  font-size: 14px;
  border: 0;
  border-bottom: 3px solid #ff0000;
}
.radio__not_required {
  font-family: "Roboto", sans-serif;
  display: inline-block;
  padding-left: 0px;
  padding-right: 0px;
  box-sizing: border-box;
  font-size: 14px;
  border: 0;
}
.placeholder_select {
  color: red;
}
.required_list {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 100%;
  margin: 0 0 15px;
  padding: 15px;
  box-sizing: border-box;
  font-size: 14px;
  border: 0;
  border-bottom: 3px solid #ff0000;
}

.required {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 100%;
  margin: 0 0 15px;
  padding: 15px;
  box-sizing: border-box;
  font-size: 14px;
  border: 0;
  border-bottom: 3px solid #ff0000;
}
.other {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 100%;
  margin: 0 0 15px;
  padding: 15px;
  box-sizing: border-box;
  font-size: 14px;
  border: 0;
  display: none;
}

.form .hide_form  {
  display: none;
}

.formBody {
  padding-top: 100px;
  width: 900px;
  margin: auto;
  display: flex;
}