Move yoga docs into docs folder on master branch

Summary: Move yoga docs into master branch so that pull requests are able to include doc updates as part of other changes.

Reviewed By: JoelMarcey

Differential Revision: D4365700

fbshipit-source-id: 2f46a88974104c454c00bcdf1257abb5c4075a68

docs/_sass/_yoga.scss

@@ -0,0 +1,98 @@
+.yoga {
+  box-sizing: border-box;
+  position: relative;
+  border: 0 solid black;
+  margin: 0;
+  padding: 0;
+  display: flex;
+  flex-direction: column;
+  align-items: stretch;
+  justify-content: flex-start;
+  flex-shrink: 0;
+}
+
+.yoga span {
+  display: flex;
+  color: white;
+  align-self: center;
+  justify-content: center;
+  flex: 1;
+}
+
+.yoga.sample {
+  border: 1px solid #ccc;
+  border-radius: 3px;
+  margin: 50px;
+  margin-left: 0px;
+  margin-right: 0px;
+  max-width: 100%;
+}
+
+.gist {
+  width: 600px;
+  margin: 50px;
+  margin-left: 0px;
+  margin-right: 0px;
+  max-width: 100%;
+}
+
+.gist .gist-meta {
+  display: none;
+}
+
+.gist .gist-data {
+  border-bottom-width: 0px !important;
+}
+
+.gist .gist-file {
+  border-color: #ccc !important;
+  margin-bottom: 0px !important;
+}
+
+.blockContent {
+  width: 600px;
+  max-width: 100%;
+}
+
+.layoutsample {
+  align-items: flex-end;
+  margin-right: 50px;
+}
+
+.gistsample {
+  align-items: flex-start;
+  margin-left: 50px;
+}
+
+.imageAlignSide .blockContent {
+  display: flex;
+	flex: 1 1;
+  flex-direction: column;
+  justify-content: center;
+}
+
+@media only screen and (max-width: 1320px) {
+  .imageAlignSide .blockContent {
+    flex-direction: row;
+    justify-content: center;
+    align-items: center;
+  }
+
+  .layoutsample {
+    flex-direction: row;
+    justify-content: center;
+    align-items: center;
+    margin-right: 0px;
+  }
+
+  .gistsample {
+    margin-left: 0px;
+  }
+
+  .gridBlock .imageAlignSide {
+    display: flex;
+    flex: 1 1;
+    flex-direction: column;
+    justify-content: center;
+  }
+}