Эффект для кнопки

@keyframes shine { 
	from { 
		opacity: 0; 
		left: 0; 
	} 
 
	50% { 
		opacity: 1; 
	} 
 
	to { 
		opacity: 0; 
		left: 100%; 
	} 
} 
 
.btn { 
	position: relative; 
	overflow: hidden; 
} 
 
.btn:after { 
	content: ''; 
	display: block; 
	width: 0; 
	height: 86%; 
	position: absolute; 
	top: 7%; 
	left: 0; 
	opacity: 0; 
	background-color: red; 
	box-shadow: 0 0 25px 5px red; 
	transform: skewX(-20deg); 
} 
 
.btn:hover { 
	transition: all 0.2s ease-out; 
} 
 
.btn:hover:after { 
	animation: shine 0.5s 0s linear; 
}

<button class="btn">Send message</button>