.aff_title { font-size: 30px; font-weight: 400; color: #4D4D4D; margin: 78px auto 46px; }
.aff_slider { position: relative; padding-top: 60%; }
.item-img { height: auto; }

.btn-group .btn-left, .btn-group .btn-right { position: absolute; width: 50px; height: 50px; line-height: 50px; font-size: 30px; text-align: center; color: #666; background: rgba(255, 255, 255, .5); border-radius: 50%; cursor: pointer; font-family: "宋体"; }

.btn-group .btn-left { left: 80px; top: 50%; margin-top: -25px; }

.btn-group .btn-right { right: 80px; top: 50%; margin-top: -25px; }

.img_list { background: #F5F5F5; padding: 30px 40px; }
.img_item { width: 24%; margin-right: 1%; }
.aff_txt { font-size: 16px; text-indent: 2em; font-weight: 400; color: #4D4D4D; line-height: 32px; padding-bottom:30px }
.mt { margin-top: 44px; }
.mb90 { margin-bottom: 92px; }
@media screen and (max-width:768px) {
    .aff_title { text-align: center; margin-top: 40px; font-size: 26px; }
    .img_list { padding: 20px; }
    .aff_txt { padding: 0 20px; text-align: justify; }
    .btn-group .btn-left, .btn-group .btn-right { position: absolute; width: 25px; height: 25px; line-height: 25px; font-size: 12px; }
    .btn-group .btn-left { left: 30px; margin-top: -12px; }

    .btn-group .btn-right { right: 30px; margin-top: -12px; }
}