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CSS

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JavaScript

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HTML 

              
                <div class="container">
	<div class="input">
		<input class="input-control" type="email" name="email" placeholder="Email" id="email" autocomplete="off" required />
		<label class="input-label" for="email">Email</label>
		<label class="input-back" for="email"></label>
	</div>
</div>
!

CSS 

              
                $goldenRatio: 1.618

$input-color-background: #F5F5F5
$input-color-label-empty: #4A4A4A
$input-color-label-filled: #9B9B9B
$input-color-label-disabled: lighten($input-color-label-empty, 20)
$input-color-control: $input-color-label-empty
$input-color-control-disabled: $input-color-label-disabled
$input-color-selection-background: $input-color-control
$input-color-selection-font: $input-color-background
$input-color-error: #FF6666
$input-duration-focus: .3s
$input-lineHeight: 1em * $goldenRatio
$input-label-scaleFactor: 1 / $goldenRatio
$input-height: 2 * $input-lineHeight
$input-padding-horizontal: ($input-height - $input-lineHeight) / 2


.input
	height: $input-height
	position: relative
	display: flex
	align-items: center
	font-family: 'Open Sans', sans-serif
	font-size: 1em

	&-control,
	&-label
		height: $input-lineHeight
		line-height: $input-lineHeight
		font-size: inherit

		&::selection
			color: $input-color-selection-font
			background: $input-color-selection-background

	&-control
		color: $input-color-control
		position: relative
		flex: 1
		z-index: 2
		padding: 0 0 0 $input-padding-horizontal
		transition: transform $input-duration-focus
		background: transparent
		border: none

		// We have our own focus effect
		&:focus 
			outline: none

		// Hack: disable the yellow webkit auto-fill background
		&:-webkit-autofill
			-webkit-box-shadow: 0 0 0 60em $input-color-background inset !important
			&,
			&:hover,
			&:focus,
			&:active
				transition-delay: 9999s
				transition-property: background-color, color

	&-label
		position: absolute
		top: 50%
		right: 0
		bottom: 0
		left: $input-padding-horizontal
		z-index: 1
		display: none // Hide this for old browsers
		transition-duration: $input-duration-focus
		transition-property: transform, color
		transform-origin: top left
		pointer-events: none
		text-align: left

	&-back,
	&-label
		margin: 0

	&-back
		position: absolute
		top: 0
		right: 0
		bottom: 0
		left: 0
		z-index: 0
		background: $input-color-background

		// Fake border using box-shadow. We animate its opacity (as opposed to the shadow itself) for performance reasons.
		&::before
			position: absolute
			top: 0
			right: 0
			bottom: 0
			left: 0
			content: ''
			display: block
			opacity: 0
			box-shadow: 0 0 0 .125em darken($input-color-background, 10)
			transition: opacity $input-duration-focus

	> *
		cursor: text

	&-control:focus ~ &-back::before
		opacity: 1

	&-control[disabled]
		color: $input-color-control-disabled
	&-control[disabled] ~ &-label
		color: $input-color-label-disabled
	&-control[disabled],
	&-control[disabled] ~ &-label,
	&-control[disabled] ~ &-back
		cursor: not-allowed

	// #### The trick ####

	// We rely on the actual placeholder in old browsers so we set its color
	&-control::placeholder
		color: $input-color-label-empty

	// But override it in newer browsers
	&-control:placeholder-shown::placeholder
		color: transparent

	// Make the first selector invalid in older browsers & match nothing in newer
	// Apply the second in browsers that support :placeholder-shown
	\:not(*):placeholder-shown,
	&-label
		display: block
		transform: translateY(-100% * $input-label-scaleFactor) scale($input-label-scaleFactor)
		color: $input-color-label-empty

	&-control:placeholder-shown ~ &-label
		transform: translateY(-50%)
		color: $input-color-label-filled

	&-control:placeholder-shown
		transform: translateY(0)

	\:not(*):placeholder-shown,
	&-control
		transform: translateY(50% * $input-label-scaleFactor)


	// Firefox-only validation:
	&-control:-moz-ui-invalid
		box-shadow: none
	&-control:-moz-ui-invalid ~ &-back::before
		box-shadow: 0 0 0 .125em $input-color-error
		opacity: 1
	&-control:-moz-ui-invalid:focus ~ &-back::before
		box-shadow: 0 0 0 .125em darken($input-color-error, 8)



// General styles
.container
	max-width: 30em
	margin: 2em auto
!

JS
!
999px

Console