body {
    background-color: rgb(0,170,255);
    margin-top: 0%;
    text-align: center;
}

.titulo {
  padding-top: 4%;
  padding-bottom: 4%;
}

.caixa {
    margin-top: 2%;
    padding-bottom: 2%;
    background: skyblue;
    width: 25%;
    border: 3px solid rgba(255, 255, 255, .3);
    border-radius: 15px;
}

.formulario {
    width: 88%;
    border-radius:15px;
    text-align: center;
    border: 2px solid rgba(0, 0, 0, .6);
    background-color: rgb(160, 240, 200);
}

.botao {
    display: inline-block;
    border: 2px solid rgba(0, 0, 0, .6);
    width: 45%;
}

input::placeholder {
    text-align:center
}

h4  {
    color: green;
}

ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #404050;
}

li {
  float: left;
  border-right: 1px solid #bbb;
}

li a {
  display: inline-block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

li a:hover {
  background-color: red;
}