Document Altair-X layout

Author: bcat

README.md

@@ -25,6 +25,7 @@ canonical ones (preferred for typing and gaming, respectively).
 
 ### Ergo
 
+* [ai03 Altair-X](keyboards/ai03/altair_x/keymaps/bcat)
 * [Lily58 layout](keyboards/lily58/keymaps/bcat)
 * [Unicorne layout](keyboards/yanghu/unicorne/keymaps/bcat)
 

keyboards/ai03/altair_x/keymaps/bcat/README.md

@@ -0,0 +1,33 @@
+# bcat's Altair-X layout
+
+This custom split ergo is essentially a high-profile Crkbd with an extra key on
+each bottom row and three macro keys on each side.
+
+<details>
+<summary>Layout notes</summary>
+
+* Based on [split 3x6+3](/layouts/split_3x6_3/bcat) layout.
+* The leftmost bottom row key is mapped to Alt, enabling easier access to combos
+  like Alt+F4.
+* The rightmost bottom row key is mapped to Super rather than just hiding it in
+  a layer.
+* The left macro keys are mapped to browser zoom hotkeys, which are annoying to
+  press otherwise.
+* The right macro keys are mapped to media keys (play/pause, next, previous).
+</details>
+
+| Default layer ([KLE](https://www.keyboard-layout-editor.com/#/gists/45acb37c9686c23498b04f370aa7ab0e)) |
+| :-: |
+| ![Layout](layer_default.png) |
+
+| Lower layer ([KLE](https://www.keyboard-layout-editor.com/#/gists/dce6f730978a7e1538fd08e21415388d)) |
+| :-: |
+| ![Layout](layer_lower.png) |
+
+| Raise layer ([KLE](https://www.keyboard-layout-editor.com/#/gists/a937f1b889842d7532dd8ba78c1bc2a5)) |
+| :-: |
+| ![Layout](layer_raise.png) |
+
+| Adjust layer (Lower+Raise, [KLE](https://www.keyboard-layout-editor.com/#/gists/437ce871d4e709ce920a5cb39f026ae3)) |
+| :-: |
+| ![Layout](layer_adjust.png) |