.form-floating { position: relative; > .form-control, > .form-control-plaintext, > .form-select { height: $form-floating-height; line-height: $form-floating-line-height; } > label { position: absolute; top: 0; left: 0; height: 100%; // allow textareas padding: $form-floating-padding-y $form-floating-padding-x; pointer-events: none; border: $input-border-width solid transparent; // Required for aligning label's text with the input as it affects inner box model transform-origin: 0 0; @include transition($form-floating-transition); } > .form-control, > .form-control-plaintext { padding: $form-floating-padding-y $form-floating-padding-x; &::placeholder { color: transparent; } &:focus, &:not(:placeholder-shown) { padding-top: $form-floating-input-padding-t; padding-bottom: $form-floating-input-padding-b; } // Duplicated because `:-webkit-autofill` invalidates other selectors when grouped &:-webkit-autofill { padding-top: $form-floating-input-padding-t; padding-bottom: $form-floating-input-padding-b; } } > .form-select { padding-top: $form-floating-input-padding-t; padding-bottom: $form-floating-input-padding-b; } > .form-control:focus, > .form-control:not(:placeholder-shown), > .form-control-plaintext, > .form-select { ~ label { opacity: $form-floating-label-opacity; transform: $form-floating-label-transform; } } // Duplicated because `:-webkit-autofill` invalidates other selectors when grouped > .form-control:-webkit-autofill { ~ label { opacity: $form-floating-label-opacity; transform: $form-floating-label-transform; } } > .form-control-plaintext { ~ label { border-width: $input-border-width 0; // Required to properly position label text - as explained above } } }