body {
  max-width: 320px;
  margin: auto;
  padding: 30px 20px;
  font-family: sans-serif;
  font-size: 14px;
}

/* Titres */
h1 {
  text-align: center;
  font-size: 20px;
}

/* Formulaires */
.btn,
button,
[type="submit"] {
  display: block;
  width: 200px;
  margin: 10px auto auto;
  padding: 8px 0;
  text-align: center;
  color: blue;
  border: 1px solid blue;
  border-radius: 4px;
  background-color: white;
}

label,
input {
  display: inline;
}

/* Apparence */
section:not(:last-of-type) {
  margin-bottom: 30px;
}

input[type="text"], input[type="email"] {
  border:0;
  border-bottom:1px solid black;
  line-height:60%;
}

.toggle-field {
  color: blue;
  cursor: pointer;
  text-decoration: underline;
}

.overlay {
  background: rgba(1, 1, 1, .3);
  height: 100%;
  top: 0;
  left: 0;
  position: absolute;
  width: 100%;
  z-index: 5;
}

.modal {
  background: #fff;
  top: 10%;
  left: 40%;
  padding: 10px;
  position: absolute;
  z-index: 10;
}