Themeing docs

docs/latest/essentials/themeing.md

@@ -1 +1,59 @@
 # Themeing
+
+Themeing is currently accomplished with color variables that are defined within
+the [`:root`](https://css-tricks.com/almanac/selectors/r/root/) selector
+(allowing them to cascade across all elements). This repository's components,
+and the ones we consume from our
+[React Viewerbase component library](https://react.ohif.org/styling-and-theming)
+utilize them. We are interested in pursuing more robust themeing options, and
+open to pull requests and discussion issues.
+
+```css
+:root {
+  /* Interface UI Colors */
+  --default-color: #9ccef9;
+  --hover-color: #ffffff;
+  --active-color: #20a5d6;
+  --ui-border-color: #44626f;
+  --ui-border-color-dark: #3c5d80;
+  --ui-border-color-active: #00a4d9;
+  --primary-background-color: #000000;
+  --box-background-color: #3e5975;
+
+  --text-primary-color: #ffffff;
+  --text-secondary-color: #91b9cd;
+  --input-background-color: #2c363f;
+  --input-placeholder-color: #d3d3d3;
+
+  --table-hover-color: #2c363f;
+  --table-text-primary-color: #ffffff;
+  --table-text-secondary-color: #91b9cd;
+
+  --large-numbers-color: #6fbde2;
+
+  --state-error: #ffcccc;
+  --state-error-border: #ffcccc;
+  --state-error-text: #ffcccc;
+
+  /* Common palette */
+  --ui-yellow: #e29e4a;
+  --ui-sky-blue: #6fbde2;
+
+  /* State palette */
+  --ui-state-error: #ffcccc;
+  --ui-state-error-border: #993333;
+  --ui-state-error-text: #661111;
+  --ui-gray-lighter: #436270;
+  --ui-gray-light: #516873;
+  --ui-gray: #263340;
+  --ui-gray-dark: #16202b;
+  --ui-gray-darker: #151a1f;
+  --ui-gray-darkest: #14202a;
+
+  --calendar-day-color: #d3d3d3;
+  --calendar-day-border-color: #d3d3d3;
+  --calendar-day-active-hover-background-color: #516873;
+  --calendar-main-color: #263340;
+  --viewport-border-thickness: 1px;
+}
+```