**Summary** **What kind of change does this PR introduce?** (check at least one) - [ ] Bugfix - [ ] Feature - [ ] Code style update - [ ] Refactor - [ ] Docs - [ ] Build-related changes - [ ] Other, please describe: If changing the UI of default theme, please provide the **before/after** screenshot: **Does this PR introduce a breaking change?** (check one) - [ ] Yes - [ ] No If yes, please describe the impact and migration path for existing applications: **The PR fulfills these requirements:** - [ ] When resolving a specific issue, it's referenced in the PR's title (e.g. `fix #xxx[,#xxx]`, where "xxx" is the issue number) You have tested in the following browsers: (Providing a detailed version will be better.) - [ ] Chrome - [ ] Firefox - [ ] Safari - [ ] Edge - [ ] IE If adding a **new feature**, the PR's description includes: - [ ] A convincing reason for adding this feature - [ ] Related documents have been updated - [ ] Related tests have been updated To avoid wasting your time, it's best to open a **feature request issue** first and wait for approval before working on it. **Other information:**