在类名前面加个/deep/就可以了

https://www.cnblogs.com/my466879168/p/12091439.html

如：

<style lang="less" scoped>
/deep/.el-form-item__content {
  line-height: 19px;
  margin-left: 0px;
}
/deep/.el-button {
  height: 51px;
  width: 352px;
}
/deep/.el-button--primary {
  background-color: #63c7bb;
  border-color: #63c7bb;
  width: 352px;
  height: 51px;
}
.login_container {
  min-height: 689px;
  width: 100%;
  min-width: 1200px;
  .nav {
    width: 100%;
    height: 90px;
    background: rgba(37, 40, 45, 1);
    padding-top: 11px;
    box-sizing: border-box;
    .w1200 {
      width: 1200px;
      margin: 0 auto;
      img {
        width: 208px;
        height: 67px;
      }
    }
  }
  .main {
    width: 100%;
    height: 1082px;
    background-image: url("../../../static/images/login_bg.png");
    background-size: 100% 100%;
    padding-top: 202px;
    box-sizing: border-box;
    .bgCenter {
      width: 1205px;
      height: 746px;
      background-image: url("../../../static/images/login_bgCenter.png");
      background-size: 100% 100%;
      margin: 0 auto;
      padding-top: 77px;
      padding-left: 97px;
      box-sizing: border-box;
      position: relative;
    }
    .more {
      width: 534px;
      height: 689px;
      background: rgba(255, 255, 255, 1);
      box-shadow: 0px 0px 30px 5px rgba(222, 255, 253, 0.46);
      border-radius: 30px;
      position: absolute;
      right: 55px;
      top: -63px;
      .twoImg {
        margin-left: 300px;
        position: relative;
        div {
          font-size: 14px;
          color: rgba(101, 101, 101, 1);
          position: absolute;
          left: 30px;
          top: 23px;
          .goewm {
            cursor: pointer;
          }
        }
      }
      .tabs {
        width: 378px;
        height: 36px;
        margin: 70px auto 36px;
        display: flex;
        justify-content: center;
        align-items: flex-start;
        border-bottom: 1px solid #e8e8e8;
        .tab {
          width: 135px;
          height: 36px;
          font-size:28px;
          color:rgba(102,102,102,1);
          line-height:4px;
          font-weight:500;
          box-sizing: border-box;
          text-align: center;

        }
        .line {
          width: 1px;
          height: 36px;
          background-color: #e8e8e8;
          margin: 0 29px;
        }
        .active {
          color: #63c7bb;
          border-bottom: 2px solid #63c7bb;
        }
      }
      .demo-ruleForm {
        width: 352px;
        margin: 0 auto;
        position: relative;
        /deep/.el-input__inner {
          height: 43px;
          background: rgba(243, 245, 248, 1);
        }
        /deep/.el-input--suffix .el-input__inner {
          padding-right: 90px;
        }
        .getCode {
          width: 55px;
          height: 24px;
          background: rgba(99, 199, 187, 1);
          box-shadow: 0px 0px 14px 1px rgba(99, 199, 187, 0.15);
          border-radius: 6px;
          text-align: center;
          color: #fff;
          font-size: 12px;
          line-height: 24px;
          position: absolute;
          right: 24px;
          top: 10px;
        }
        .ty {
          margin-top: 29px;
          margin-bottom:8px;
        }
        .ruleForm_gologin{
          font-size: 14px;
          text-align: right;
          color: #63c7bb;
          cursor: pointer;
          padding-bottom: 40px;
          span{
            font-weight:500;
            border-bottom: 1px solid #63c7bb;
          }      
        }
        .loginBox {
          span {
            font-size: 12px;
            a {
              color: #63c7bb;
            }
          }
        }
      }
    }
  }
  </style>

为了避免全局影响，要在前面加上最外层盒子的类名