.ptPic {
	height: 475px; width: 100%; overflow: hidden;
}
	.ptImg {
		height: 475px; width: 1400px; overflow: hidden;
		display: none;
	}
	.ptTip {
		display: none;
	}


.ptNavBox {
	margin: 80px auto 55px; padding: 0;
	height: 140px; width: 100%; overflow: hidden;
}
	.ptNav {
		margin: 0 auto; padding: 0;
		height: 140px; width: 1400px; overflow: hidden;
	}
		.ptnUl {
			display: block;
			margin: 0 auto; padding: 0;
			height: 140px; width: 1400px; overflow: hidden;
		}
			.ptnLi {
				display: block;
				height: 140px; width: 680px; overflow: hidden;
				cursor: pointer;
			}
				.ptnPic {
					display: block;
					height: 140px; width: 680px; overflow: hidden;
				}
					.ptnImg {
						display: block;
						height: 140px; width: 680px; overflow: hidden;
					}
					.ptnTip {
						display: none;
					}

.productBox {
	min-height: 1300px; width: 100%; overflow: hidden;
	margin: 0; padding: 0;
}
	.product {
		min-height: 1300px; width: 1400px; overflow: hidden;
		margin: 0 auto; padding: 0;
	}
		.list {
			display: block; margin: 0; padding: 0;
			min-height: 1300px; width: 1400px; overflow: hidden;
		}
			.ptLi {
				display: block; margin: 0 0 60px; 
				height: 648px; width: 684px; overflow: hidden;
				border: 3px solid #f3f3f3; 
				background-color: #f3f3f3;
			}
			.ptLi:nth-child(2n+1) {
				float: left;
				padding: 0;
			}
			.ptLi:nth-child(2n) {
				padding: 0;
				float: right;
			}
				.ptDl {
					display: block; margin: 0; padding: 0;
				}
				.ptDt {
					display: block; margin: 0; padding: 0;

				}
					.ptdPic {
						display: block; margin: 0; padding: 0;
						height: 460px; width: 684px; overflow: hidden;
						position: relative;
					}
						.ptdImg {
							display: block; margin: 0; padding: 0;
							height: 460px; width: 684px; overflow: hidden;
						}
						.ptdTip {
							display: none;
						}
						.ptdPic:hover .ptdTip {
							display: block;
							position: absolute; left: 0; top: 0; z-index: 3;
							height: 460px; width: 684px; overflow: hidden;
							background: url('../img/product_demo_2_cur.png') no-repeat left top;
							background-size: 684px 460px;
						}
				.ptTitle {
					display: block; margin: 20px auto 0; padding: 0;
					height: 75px; width: 90%; overflow: hidden;
					font-size: 40px; line-height: 75px;
					color: #333333;
				}
				.ptDd {
					display: block; margin: 0 auto; padding: 0;
					height: 55px; width: 90%; overflow: hidden;
					font-size: 25px; line-height: 55px;
					color: #999999;
				}
					.ptTitle:hover,
					.ptDd:hover {
	    				color: #1752a3;
					}