siyuan/app/src/assets/scss/_form.scss

.b3-form {
  &__space {
    margin: 16px 24px;

    &--small {
      margin: 8px 16px;
    }
  }

  &__icon {
    position: relative;
    color: var(--b3-theme-on-surface);

    &-icon {
      position: absolute;
      left: 9px;
      top: 7px;
      height: 16px;
      width: 16px;

      &--current {
        color: var(--b3-theme-primary);
        background-color: var(--b3-theme-surface);
      }
    }

    &-action {
      right: 9px;
      top: 5px;
      border-radius: 2px;
      text-align: center;
      padding: 2px;
      position: absolute;
      height: 16px;
      width: 16px;

      &:hover {
        background-color: var(--b3-theme-surface);
        color: var(--b3-theme-primary);
      }
    }

    &-input {
      padding-left: 35px !important;
    }

    &--small {
      .b3-form__icon-icon {
        left: 5px;
        top: 4px;
        height: 14px;
        width: 14px;
      }

      .b3-form__icon-input {
        padding-left: 25px !important;
      }
    }
  }

  &__img {
    position: relative;

    img {
      position: absolute;
      left: 1px;
      top: 1px;
      height: 28px;
      border-radius: 3px 0 0 3px;
    }

    input {
      padding-left: 93px;
    }
  }

  &__upload {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    opacity: .001;
    overflow: hidden;
    cursor: pointer
  }
}

.b3-label {
  border-bottom: 1px solid var(--b3-border-color);
  padding: 16px 24px;
  line-height: 20px;

  &__text {
    color: var(--b3-theme-on-surface) !important;
    font-size: 14px !important;
    margin-top: 4px;
    overflow: hidden !important;
  }

  &:last-child {
    border-bottom: 0;
  }
}