Stick footer to bottom (#369)

* Stick to bottom

* Use variable

Author: jarrodmillman

assets/theme-css/styles.css

@@ -165,6 +165,8 @@ a > code {
 }
 #footer {
   background-color: var(--colorPrimaryDark);
+  position: sticky;
+  top: calc(100vh - var(--spht-footer-height));
 }
 
 .footer-logo-column {

assets/theme-css/vars.css

@@ -2,7 +2,6 @@
 :root {
   --fontFamily: "{{ .Site.Params.font.name }}", "Noto Sans Symbols 2";
 
-  /* First we name the colors of our theme's palette. */
   --colorPrimaryDark: rgb(1, 50, 67);
   --colorPrimary: rgb(77, 119, 207);
   --colorPrimaryLight: rgb(77, 171, 207);
@@ -13,4 +12,6 @@
 
   --colorBrightBlue: rgb(30, 135, 240);
   --colorYellow: rgb(255, 197, 83);
+
+  --spht-footer-height: 6em;
 }