样式出界是什么属性的配置问题？

Question

样式出界如图所示，当前页面的样式如下。

<style lang="scss">
.board {
  width: 1000px;
  margin-left: 20px;
  display: flex;
  overflow-x: auto;
  justify-content: space-around;
  flex-direction: row;
  align-items: flex-start;
}
.kanban {
  &.todo {
    .board-column-header {
      background: #4A9FF9;
    }
  }
  &.working {
    .board-column-header {
      background: #f9944a;
    }
  }
  &.done {
    .board-column-header {
      background: #2ac06d;
    }
  }
}.board-column {
  min-width: 300px;
  min-height: 100px;
  height: auto;
  overflow-x: auto;
  background: #f0f0f0;
  border-radius: 3px;

  .board-column-header {
    .el-input{
      .el-input__inner {
        color: white;
        border: none;
        background: transparent;
      }
    }
    height: 50px;
    line-height: 50px;
    overflow: hidden;
    padding: 0 20px;
    margin: 0 3% 0 0;
    text-align: center;
    background: #333;
    color: #fff;
    border-radius: 3px 3px 0 0;
  }

  .board-column-content {
    height: auto;
    overflow: hidden;
    border: 10px solid transparent;
    min-height: 60px;
    display: flex;
    overflow-y: auto;
    justify-content: flex-start;
    flex-direction: column;
    align-items: center;

    .board-item {
      .el-input{
        .el-input__inner {
          border: none;
        }
      }
      .el-textarea{
        .el-textarea__inner {
          border: none;
        }
      }

      cursor: pointer;
      width: 100%;
      height: 64px;
      margin: 5px 0;
      background-color: #fff;
      text-align: left;
      line-height: 54px;
      padding: 5px 10px;
      box-sizing: border-box;
      box-shadow: 0px 1px 3px 0 rgba(0, 0, 0, 0.2);
    }
  }
}
</style>