The orientation CSS descriptor controls the orientation of a document defined by @viewport.
/* Keyword values */ orientation: auto; orientation: portrait; orientation: landscape;
For a UA/device where the orientation is changed upon tilting the device, an author can use this descriptor to inhibit the orientation change.
autoportraitlandscape| Related at-rule | @viewport | 
|---|---|
| Initial value | auto | 
| Percentages | refer to the size of bounding box | 
| Computed value | as specified | 
auto | portrait | landscape
@viewport {
  orientation: landscape;
} | Specification | Status | Comment | 
|---|---|---|
| CSS Device Adaptation The definition of '"orientation" descriptor' in that specification.  |  Working Draft | Initial definition | 
| Desktop | ||||||
|---|---|---|---|---|---|---|
orientation descriptor | 
No | 12 — 79
  | 
No |  10
  | 
No | No | 
| Mobile | ||||||
|---|---|---|---|---|---|---|
orientation descriptor | 
No | No | No | 11.1 — 14
  | 
No | No | 
    © 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
    https://developer.mozilla.org/en-US/docs/Web/CSS/@viewport/orientation