.course-development-box {
  display: block;
}

.course-development-box {
  padding-top: 100px;
  height: 780px;
  background: url(404.png) no-repeat center center;
  background-size: cover;
  overflow: hidden;
}

.course-development-box img {
  vertical-align: middle;
  max-width: 100%;
  height: auto;
}

.course-development-box * {
  box-sizing: border-box;
}

.course-development-box > h3 {
  margin-bottom: 25px;
  color: #000000;
  text-align: center;
  letter-spacing: 4px;
  font-size: 2.1875rem;
  font-family: sans-serif;
}

.even-box {
  position: relative;
  padding-top: 90px;
  height: 440px;
  width: 100%;
  margin-top: 100px;
}

.event-list {
  margin-bottom: 50px;
  height: 200px;
}

.event-list:before {
  width: 100%;
  position: absolute;
  top: 89px;
  left: 0;
  z-index: -1;
  height: 2px;
  background: #999;
  box-shadow: 0 0 1px #000;
  display: block;
  content: ' ';
}


.even-box .page {
  position: relative;
  left: 50%;
  margin-left: -228px;
  width: 340px;
  height: 55px;
  text-align: center;
  font-size: 1.125rem;
  line-height: 55px;
}

.even-box .page .prev {
  background-color: #c5c5c5;
  color: rgba(255, 255, 255, 0.7);
  font-family: number;
}

.even-box .page .next {
  background-color: #337FE5;
  color: rgba(255, 255, 255, 0.7);
  font-family: number;
}

.even-box .page .prev *, .even-box .page .next * {
  pointer-events: none;
}

.even-box .page div {
  float: left;
  width: 50%;
  letter-spacing: 5px;
  font-family: sans-serif;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

.even-box .show-box {
  position: absolute;
  right: 50%;
  bottom: 40px;
  overflow: hidden;
  margin-right: 230px;
  width: 420px;
  height: 430px;
  background-color: #fff;
  -webkit-box-shadow: 0PX 20px 70px #c5c5c5;
  box-shadow: 0PX 20px 70px #c5c5c5;
}

.show-box ul {
  height: 360px;
  -webkit-transition: all 0.5s;
  transition: all 0.5s;
  list-style: none;
  padding: 0;
  margin: 0;
}

.show-box li {
  float: left;
  padding: 10px;
  width: 500px;
  height: 100%;
}

.show-box li .pic {
  position: relative;
  overflow: hidden;
  margin-bottom: 24px;
}

.show-box li .p1 {
  text-align: center;
  color: #555;
  font-size: 14px;
  line-height: 1.5;
}

.event-list ul {
  position: relative;
  padding: 0;
  margin: 0;
  margin-left: 50%;
  height: 1px;
  background-color: #999;
  -webkit-box-shadow: 0 0 1px #000;
  box-shadow: 0 0 1px #000;
  -webkit-transition: all 0.5s;
  transition: all 0.5s;
  list-style: none;
}

.event-list ul li {
  position: absolute;
  width: 140px;
  height: 100px;
  color: #4c4c4c;
  text-align: center;
  font-size: 3.75rem;
  transition: all 500ms;
}

.event-list ul li.on .dian i {
  background-color: #337FE5;
}

.event-list ul li .dian {
  position: absolute;
  left: 50%;
  z-index: 3;
  display: block;
  margin-left: -10px;
  width: 20px;
  height: 20px;
  border-radius: 100%;
  background-color: #fff;
  -webkit-box-shadow: 0 0 8px #bbb;
  box-shadow: 0 0 8px #bbb;
}

.event-list ul li.on::before {
  opacity: 1;
}

.event-list ul li::before {
  position: absolute;
  left: 50%;
  z-index: 2;
  display: block;
  width: 400px;
  height: 1px;
  background-color: #337FE5;
  -webkit-box-shadow: 0 0 1px #337FE5;
  box-shadow: 0 0 1px #337FE5;
  content: '';
  opacity: 0;
}

.event-list ul li.on .year {
  color: #337FE5;
  text-shadow: 0 6px 16px rgb(132 186 81 / 40%);
}

.event-list ul li .year {
  position: absolute;
  right: 0;
  left: 0;
  display: block;
  width: 100%;
  letter-spacing: 3px;
  font-family: number;
  cursor: pointer;
}

.event-list ul li .dian i {
  display: block;
  margin: 5px;
  width: 10px;
  height: 10px;
  border-radius: 100%;
  background-color: #4d4d4d;
}

.event-list ul li:last-child::before {
  right: 50%;
  left: auto;
}

.event-list ul li:nth-child(even) {
  top: -100px;
}

.event-list ul li:nth-child(odd) {
  bottom: -100px;
}

.event-list ul li:nth-child(odd)::before {
  top: 0;
}

.event-list ul li:nth-child(even)::before {
  bottom: -1px;
}

.event-list ul li:nth-child(odd) .year {
  bottom: 0;
}

.event-list ul li:nth-child(even) .year {
  top: 0;
}

.event-list ul li:nth-child(even) .dian {
  bottom: -10px;
}

.event-list ul li:nth-child(odd) .dian {
  top: -10px;
}

.event-list ul li:nth-child(odd) .text_overflow {
  top: -90px;
}

.event-list ul li:nth-child(even) .text_overflow {
  bottom: -90px;
}

.event-list ul li .text_overflow {
  position: absolute;
  left: 50%;
  margin-left: -150px;
  width: 350px;
  text-align: center;
  letter-spacing: 2px;
  font-size: 1rem;
  cursor: pointer;
  height: 80px;

  -webkit-box-orient: vertical;
  text-overflow: ellipsis;
  -webkit-line-clamp: 2;
  color: #4c4c4c;
  font-size: 14px;

}