게시판이 찌그러짐 현상?

초보자 고수님들께 질문 좀 드립니다.

그림처럼 게시판이 좁아졌는데...

어느부분을 수정해야 되나요?

/* 중간 레이아웃 */

#wrapper {}

#container_wr:after {display:block;visibility:hidden;clear:both;content:""}

#container_wr {margin:0 auto;height:100%;zoom:1}

#aside {float:right;width:270px;padding:0;height:100%;margin: 20px 0 0 0}

#container {position:relative;float:left;min-height:500px;height:auto !important;margin:20px 0;height:500px;font-size:1em;width:900px;zoom:1}

#container:after {display:block;visibility:hidden;clear:both;content:""}

#container_title {font-size:1.333em;margin:0 auto;font-weight:bold}

#container_title span {margin:0 auto 10px;display:block;line-height:30px}

.lt_wr {width:32%}

.lt_wr:nth-child(3n+1) {clear:both}

.latest_wr {margin-bottom:20px}

.latest_wr:after {display:block;visibility:hidden;clear:both;content:""}

.latest_top_wr {margin:0 -10px 20px}

.latest_top_wr:after {display:block;visibility:hidden;clear:both;content:""}