Refactor and restyle documentation

docs/src/docs/asciidoc/css/page.css

@@ -0,0 +1,74 @@
+body {
+    background: linear-gradient(rgba(0, 0, 0, 0.8), rgba(0, 0, 0, 0.85));
+    color: white;
+}
+
+#grabbit-logo {
+    position: absolute;
+    right: 0;
+    top: 0;
+    width: 150px;
+}
+
+#toc {
+    background: none !important;
+}
+
+#toc > #toctitle {
+    color: #ffc107;
+}
+
+#header > h1:first-child {
+    color: white;
+    font-weight: 600;
+}
+
+#header>.details {
+    color: white;
+}
+
+#preamble>.sectionbody>[class="paragraph"]:first-of-type p {
+    color: white;
+}
+
+h2, h3, h4, .title {
+    color: #ffc107 !important;
+}
+
+p {
+    color: white;
+}
+
+a {
+    color: #00a8cd;
+}
+
+a:hover {
+    color: #ffc107;
+}
+
+.listingblock >.content>pre:not(.highlight) {
+    color: white;
+    background: none;
+    border: 1px solid #ffc107;
+    border-radius: 4px;
+}
+
+:not(pre):not([class^=L])>code {
+    background: #00758F;
+    color: white;
+}
+
+.admonitionblock td.icon .icon-tip::before,
+.admonitionblock td.icon .icon-note::before,
+.admonitionblock td.icon .icon-warning::before {
+    color: white;
+}
+
+.admonitionblock>table td.content {
+    color: white;
+}
+
+#footer {
+    background: rgba(0, 0, 0, 0.2);
+}

docs/src/docs/asciidoc/docinfo-footer.html

@@ -1,7 +1,8 @@
 <link rel="stylesheet" href="css/multi-lang-sample.css">
+<link rel="stylesheet" href="css/page.css">
 <script src="js/multi-lang-sample.js"></script>
 <div id="footer">
     <div id="footer-text">
-        <img src="img/GraalVM-rgb.svg" alt="GraalVM"> (c) {docyear}. Licensed under the Universal Permissive License (UPL), Version 1.0
+        <img src="css/images/GraalVM-rgb.svg" alt="GraalVM"> (c) {docyear}. Licensed under the Universal Permissive License (UPL), Version 1.0
     </div>
 </div>

docs/src/docs/asciidoc/docinfo-header.html

@@ -0,0 +1,3 @@
+<div id="grabbit-logo">
+    <img src="css/images/Grabbit.svg" alt="">
+</div>