.container{
  height: 100%;
}
.nav {
    height: 85rpx;
    width: 100%;
    box-sizing: border-box;
    overflow: hidden;
    line-height: 70rpx;
    font-size: 16px;
    white-space: nowrap;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 99;
}
.nav-item {
    width: 33%;
    display: inline-block;
    text-align: center;
}
.active{
    color: green;
    border-bottom: 3rpx solid green;
}

.tab-box{
    padding-top: 85rpx;
    height: 100%;
    box-sizing: border-box;
}
.tab-content{
  overflow-y: scroll;
  width: 100%;
}

.grade{
  background: white;
  padding: 20rpx 10rpx;
  border-bottom: 1rpx solid gray;
}

.grade text{
  margin: 0rpx 20rpx;
}
.time{
  position: fixed;
  right: 180rpx;
}

.mark{
  position: fixed;
  right: 3rpx;
  padding: 3rpx 23rpx;
  width: 45rpx;
  text-align: center;
}
.add{
  color: white;
  background: green;
  border-radius: 12rpx;
}
.delete{
  color: white;
  background: red;
  border-radius: 12rpx;
}