<div class="cp_iptxt">
	<label class="ef">
	<input type="text" placeholder="お名前">
	</label>
</div>

.cp_iptxt {
	position: relative;
	width: 80%;
	margin: 40px 3%;
}
.cp_iptxt input[type='text'] {
	font: 15px/24px sans-serif;
	box-sizing: border-box;
	width: 100%;
	padding: 0.3em;
	transition: 0.3s;
	letter-spacing: 1px;
	color: #aaaaaa;
	border: none;
	border-bottom: 2px solid #1b2538;
	background: transparent;
}
.ef input[type='text']:focus {
	border-bottom: 2px solid #da3c41;
	outline: none;
}