.chapter_box {
  position: relative;
  width: 1200px;
}
.chapter {
  width: 765px;
  height: 56px;
  margin: 0 auto;
  background: url("https://image-storage.oss-cn-hangzhou.aliyuncs.com/image/173uu/encyclopedias/pianzhangqiehuan.png");
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.chapter_left {
  font-size: 18px;
  color: #f4dec8;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
  margin-left: 117px;
}
.chapter_right {
  font-size: 18px;
  color: #fde051;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
  margin-right: 32px;
  cursor: pointer;
}
.chapter_right_txt {
  display: inline-block;
  width: 180px;
  text-align: center;
  margin-right: 12px;
}
.chapter_right img {
  position: relative;
  top: -2px;
}
.chapter_right img:last-of-type {
  display: none;
}
.drop_down {
  position: absolute;
  width: 180px;
  background: url("https://image-storage.oss-cn-hangzhou.aliyuncs.com/image/173uu/encyclopedias/pianzhangxialabeijing.png");
  background-repeat: repeat-y;
  background-size: cover;
  top: 56px;
  box-sizing: border-box;
  right: 282px;
  border: 1px solid #692b21;
  z-index: 100;
  display: none;
}
.drop_down.is_large {
  width: 1200px;
  right: 0px;
  padding: 0 0 0 12px;
  flex-wrap: wrap;
}
.drop_down.is_large a {
  font-size: 14px;
}
.drop_down a {
  font-size: 16px;
  color: #f4dec8;
  line-height: 32px;
  display: inline-block;
  width: 100%;
  text-align: center;
}
.drop_down a:hover,
.drop_down li.current a {
  background: #340902;
  color: #fde051;
}
.drop_down li {
  border-top: 1px solid #692b21;
  padding: 6px 0;
  width: 100%;
}
.drop_down li:first-of-type {
  border-top: none;
}
.drop_down.is_large li {
  width: 144px;
  padding-right: 3px;
  border-top: none;
  border-bottom: 1px solid #692b21;
  float: left;
  margin-bottom: -1px;
}
.drop_down.is_large li:nth-of-type(8n) {
  margin-right: 0;
}