ionic-framework/ionic/components/form/form.scss

// Forms
// --------------------------------------------------


form {
  margin: 0 0 2.4rem;
}

label,
input,
select,
textarea {
  line-height: normal;
  font-family: inherit;
}


// Form Controls
// -------------------------------

.item-input {

  // text inputs
  textarea,
  input[type="text"],
  input[type="password"],
  input[type="datetime"],
  input[type="datetime-local"],
  input[type="date"],
  input[type="month"],
  input[type="time"],
  input[type="week"],
  input[type="number"],
  input[type="email"],
  input[type="url"],
  input[type="search"],
  input[type="tel"],
  input[type="color"] {
    display: block;
    background: transparent;
    border: 0;
    width: 100%;
  }

  // tap inputs
  input[type="radio"],
  input[type="checkbox"] {
    margin: 0;
  }

  input[type="file"],
  input[type="image"],
  input[type="submit"],
  input[type="reset"],
  input[type="button"],
  input[type="radio"],
  input[type="checkbox"] {
    width: auto;
  }
}

textarea {
  height: auto;
  padding: 0;
}

.platform-mobile textarea {
  resize: none;
}


// Placeholder
// -------------------------------
input,
textarea {
  @include placeholder();
}


// DISABLED STATE
// -------------------------------

// Disabled and read-only inputs
input[disabled],
select[disabled],
textarea[disabled],
select[readonly] {
  cursor: not-allowed;
}
// Explicitly reset the colors here
input[type="radio"][disabled],
input[type="checkbox"][disabled],
input[type="radio"][readonly],
input[type="checkbox"][readonly] {
  background-color: transparent;
}