RichTextBox for UWP supports many CSS properties. The following table lists CSS properties by name and media group and notes whether they are supported by RichTextBox for UWP.
| Name | Media Groups | Supported | Comments |
| azimuth | aural | NO | |
| background-attachment | visual | NO | |
| background-color | visual | YES | |
| background-image | visual | YES | The image is not repeated. |
| background-position | visual | NO | |
| background-repeat | visual | NO | |
| background | visual | YES | Only supports color and image. |
| borer-collapse | visual | YES | |
| border-color | visual | YES | |
| border-spacing | visual | YES | |
| border-style | visual | YES | Supports 'none', 'hidden', and solid. Other values are treated as solid. |
| border-top border-right border-bottom border-left | visual | YES | |
| border-top-color border-right-color border-bottom-color border-left-color | visual | YES | |
| border-top-style border-right-style border-bottom-style border-left-style | visual | YES | |
| border-top-width border-right-width border-bottom-width border-left-width | visual | YES | |
| borer-width | visual | YES | |
| border | visual | YES | |
| bottom | visual | YES | |
| caption-side | visual | NO | |
| clear | visual | NO | |
| clip | visual | NO | |
| color | visual | YES | |
| content | all | NO | |
| counter-increment | all | NO | |
| counter-reset | all | NO | |
| cue-after | aural | NO | |
| cue-before | aural | NO | |
| cue | aural | NO | |
| cursor | visual, interactive | YES | All values except crosshair, move, progress, help, and <uri>. |
| direction | visual | NO | |
| display all | all | YES | All values except run-in, inline-block, inline-table, and table-caption. |
| elevation | aural | NO | |
| empty-cells | visual | NO | |
| float | visual | NO | |
| font-family | visual | YES | |
| font-size | visual | YES | |
| font-style | visual | YES | |
| font-variant | visual | NO | |
| font-weight | visual | YES | |
| font | visual | YES | |
| height | visual | YES | Only in img elements. |
| left | visual | YES | |
| letter-spacing | visual | NO | |
| line-height | visual | NO | |
| list-style-image | visual | YES | |
| list-style-position | visual | YES | |
| list-style-type | visual | NO | All values except Georgian, Armenian, and lower-Greek. |
| list-style | visual | YES | |
| margin-right margin-left | visual | YES | |
| margin-top margin-bottom | visual | YES | |
| margin | visual | YES | |
| max-height | visual | NO | |
| max-width | visual | NO | |
| min-height | visual | NO | |
| min-width | visual | NO | |
| orphans | visual, paged | NO | |
| outline-color | visual, interactive | NO | |
| outline-style | visual, interactive | NO | |
| outline-width | visual, interactive | NO | |
| outline | visual, interactive | NO | |
| overflow | visual | NO | |
| padding-top padding-right padding-bottom padding-left | visual | YES | |
| padding | visual | YES | |
| page-break-after | visual, paged | NO | |
| page-break-before | visual, paged | NO | |
| page-break-inside | visual, paged | NO | |
| pause-after | aural | NO | |
| pause-before | aural | NO | |
| pause | aural | NO | |
| pitch-range | aural | NO | |
| pitch | aural | NO | |
| play-during | aural | NO | |
| position | visual | NO | |
| quotes | visual | NO | |
| richness | aural | NO | |
| right | visual | NO | |
| speak-header | aural | NO | |
| speak-numeral | aural | NO | |
| speak-punctuation | aural | NO | |
| speak | aural | NO | |
| speech-rate | aural | NO | |
| stress | aural | NO | |
| table-layout | visual | NO | |
| text-align | visual | YES | |
| text-decoration | visual | YES | |
| text-indent | visual | YES | |
| text-transform | visual | NO | |
| top | visual | NO | |
| unicode-bidi | visual | NO | |
| vertical-align | visual | YES | All values except <percentage> and <length>. |
| visibility | visual | YES | |
| voice-family | aural | NO | |
| volume | aural | NO | |
| white-space | visual | YES | Nowrap and pre are treated like normal and pre-wrap. |
| windows | visual, paged | NO | |
| width | visual | YES | Only in img elements. |
| word-spacing | visual | NO | |
| z-index | visual | NO |
