.cta-mail-banner {
  padding: 20px 0;

  background: #f0f0f0;
  border-radius: 5px;
  border: 1px solid #e6e6e6;
}

.cta-mail-text {
  margin: 0 0 15px;

  font-size: 18px;
  text-align: center;
}

.cta-mail-form {
  display: flex;
  justify-content: center;
}

.cta-mail-field {
  width: 400px;
  margin-right: 15px;
  padding: 9px 10px;

  border: 1px solid #ccc;
  border-radius: 5px;
}

.cta-mail-button {
  padding: 10px 20px;

  background: #ef5350;
  border: 0;
  border-radius: 5px;

  color: #fff;
}
.cta-mail-banner {
  padding: 10px;

  background: #f0f0f0;
  border-radius: 5px;
  border: 1px solid #e6e6e6;
}

.cta-mail-text {
  margin: 0 0 15px;

  font-size: 16px;
  text-align: center;
}

.cta-mail-field {
  width: 100%;
  padding: 9px 10px;

  border: 1px solid #ccc;
  border-radius: 5px;
}

.cta-mail-button {
  display: block;
  width: 100%;
  margin-top: 10px;
  padding: 10px 20px;

  background: #ef5350;
  border: 0;
  border-radius: 5px;

  color: #fff;
}

@media only screen and (min-width: 680px) {
  .cta-mail-banner {
    padding: 20px;
  }

  .cta-mail-text {
    font-size: 18px;
  }

  .cta-mail-form {
    display: flex;
    justify-content: center;
  }

  .cta-mail-field {
    width: 400px;
    margin-right: 15px;
  }

  .cta-mail-button {
    display: inline-block;
    width: auto;
    margin-top: 0;
  }
}
Fix cta in small screens
Fix cta in small screens
