.contact-form .form-control {
  width: 100%;        /* full width on small screens */
  max-width: 500px;   /* fixed width on large screens */
  margin: 0 auto;     /* center the input when max-width applies */
  padding: 12px 15px;
  font-size: 16px;
  display: block;
  resize: none;
}

.contact-form .form-group {
  margin-bottom: 20px;
  text-align: center; /* centers inputs horizontally */
}

.mail-send {
  color: white;
  background-color: var(--blue-btn) !important;
  box-shadow:0 15px 35px rgba(0,0,0,0.08);
  padding: 9px 30px;
  border-radius: .5rem;
  font-family: "Roboto", sans-serif;
  transition: .5s;
  font-size: 1.2rem;
}

.mail-send:hover {
  opacity: .8;
  color: white;
}

@media only screen and (max-width: 600px) {
  .mail-send {
    width: 100%;
  }
}