img {
	display: block;
	width: 100%;
}

.wrapper {
	text-align: center;
	margin: 0 auto;
}

.show {
}

/* 當螢幕寬度為1200px */
@media screen and (min-width: 1200px) {
	.wrapper {
		width: 1200px;
	}
	.w720 {
		display: none;
	}
	.w320 {
		display: none;
	}
}

/*當螢幕寬度在481px~850px之間*/
@media all and (min-width: 481px) and (max-width: 1199px){
	.wrapper {
		width: 720px;
	}
	.w1200 {
		display: none;
	}
	.w320 {
		display: none;
	}

}

/*當螢幕最小寬度為480px*/
@media all and (max-width: 480px){
	.wrapper {
		width: 320px;
	}
	.w1200 {
		display: none;
	}
	.w720 {
		display: none;
	}
}