body {
  font-family: sans-serif;
  font-weight: 300;
  font-size: 18px;
}

div {
  margin: 5;
}

.form_beschikbaar {
  display: flex; /* or inline-flex */
  flex-direction: column;
  text-align: center;
}

.form_2 {
  display: flex; /* or inline-flex */
  flex-direction: row;
  text-align: center;
}

.form_date {
  margin-top: 20px;
  margin-bottom: 20px;
}

.form_cijfer {
  margin-top: 20px;
  margin-bottom: 20px;
}

.form_cijfer_input {
  border-radius: 5px;
  padding: 8px;
  margin-left: 15px;
}

.form_submit {
  border-radius: 5px;
  padding: 10px;
}