* {box-sizing: border-box}

  input[type=text] {
  width: 100%;
  padding: 15px;
  margin: 5px 0 22px 0;
  display: inline-block;
  border: none;
  background: #f1f1f1;
}

input[type=text]:focus {
  background-color: #ddd;
  outline: none;
}

hr {
  border: 1px solid #f1f1f1;
  margin-bottom: 25px;
}


button {
  background-color: #4CAF50;
  color: white;
  padding: 14px 20px;
  margin: 8px 0;
  border: none;
  cursor: pointer;
  width: 100%;
  opacity: 0.9;
}

button:hover {
  opacity:1;
}

.btnvalider {
  float: left;
  width: 25%;
   margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.container {
  padding: 16px;
  
}

.clearfix::after {
  content: "";
  clear: both;
  display: table;
 margin-left: auto;
  margin-right: auto;}

@media screen and (max-width: 300px) {
  .btnvalider {
    width: 100%;
     margin-left: auto;
  margin-right: auto;
  }
}