framework/less/common/FormControl.less

.FormControl {
  --transition: border-color .15s, background .15s;
  display: block;
  width: 100%;
  height: 36px;
  padding: 8px 13px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--control-color);
  background-color: var(--control-bg);
  border: 2px solid transparent;
  border-radius: var(--border-radius);
  transition: var(--transition);
  -webkit-appearance: none;

  &:focus {
    background-color: var(--body-bg);
    color: var(--text-color);
    border-color: var(--primary-color);
    outline: none;
  }

  // Placeholder
  .placeholder(var(--control-color));

  // Disabled and read-only inputs
  &[disabled],
  &[readonly],
  fieldset[disabled] & {
    opacity: 0.5;
  }

  &[disabled],
  fieldset[disabled] & {
    cursor: not-allowed;
  }

  textarea& {
    height: auto;
  }

  @media @phone {
    font-size: 16px; // minimum font-size required to prevent page zoom on focus in iOS 10
  }
}

.helpText {
  font-size: 12px;
  line-height: 1.5em;
  margin-bottom: 10px;
  color: var(--muted-color);
}