feat: add a switch to toggle light/dark theme

Add script for restoring preferred theme setting.
Update config for newer `mkdocs-material`.
Use native `mkdocs-material` styles where possible.

Closes: #45 #63

docs/css/styles.css

@@ -4,7 +4,7 @@
 
 article img {
     border: 1px solid #eee;
-    box-shadow: 0 0 1em #ccc;
+    box-shadow: 0 0 1em rgba(0, 0, 0, .6);
     margin: 30px auto 10px;
 }
 
@@ -24,30 +24,17 @@ article img.emojione {
     background-color: #0d9cec !important;
 }
 
-@font-face{
-    font-family: "Geomanist";
-    src: url("../fonts/hinted-Geomanist-Book.ttf")
+.md-header__button.md-logo img,
+.md-nav__title .md-nav__button.md-logo img {
+    height: 1.4rem;
+    width: auto;
 }
 
-body {
-    font-family: "Open Sans", sans-serif;
-    font-size: 15px;
-    font-weight: normal;
-    font-style: normal;
-    font-stretch: normal;
-    line-height: 1.5;
-    letter-spacing: normal;
-    color: #577482;
-}
-
-h1, h2, h3, h4, .md-footer-nav__inner, .md-header-nav__title, footer.md-footer {
-    font-family: Geomanist;
-}
-
-.md-header-nav__title {
-    line-height: 2.9rem;
+.md-nav__title .md-nav__button img {
+    height: 30px;
+    margin-top: 10px;
 }
 
 .md-header-nav__button img {
     width: 145px;
-}
+}

docs/index.md

@@ -1,2 +0,0 @@
-redirect: /tutorial/
-

docs/js/index.js

@@ -0,0 +1,4 @@
+const settings = JSON.parse(localStorage.getItem(__prefix('__palette')));
+const scheme = settings?.color.scheme || (matchMedia('(prefers-color-scheme: dark)').matches ? 'slate' : 'default' );
+
+document.body.setAttribute('data-md-color-scheme', scheme);