A new theme for the kitty website

Supports dark mode. Also re-organize the documentation
a bit, making it more hierarchical.

Have a nicer landing page

docs/_static/custom.css

@@ -5,118 +5,11 @@
  * Distributed under terms of the MIT license.
  */
 
-.float-left-img {
-    float: left;
-    margin-right: 1em;
-    margin-bottom: 1em;
-}
-
-.float-right-img { float: right; margin-left: 1em; margin-bottom: 1em }
-
-.half-with-img { max-width: 50% }
-
-.fit-img { max-width: 95% }
-
-div.body {
-    min-width: 200px;
-}
-
-pre {
-    white-space: pre-wrap;
-}
-
-pre.pre {
-    white-space: pre;
-}
-
-a[href], input[type="submit"] { cursor: pointer; }
-
-img[style] {
-    /* Used for :scale: images to have them render properly but still popup when clicked */
-    width: auto !important;
-    height: auto !important;
-}
-
-a {
-    text-decoration: none !important;
-    border-bottom: none !important;
-}
-
-body div.document {
-    margin-top: 1ex;
+.sidebar-logo {
+    max-height: 128px;
 }
 
 .major-features li {
-    margin-top: 0.75ex;
     margin-bottom: 0.75ex;
-}
-
-.support-form input[type=submit] {
-    border-radius: 6px;
-    box-shadow: rgb(255, 246, 175) 0px 1px 0px 0px;
-    background: linear-gradient(rgb(255, 236, 100) 5%, rgb(255, 171, 35) 100%) rgb(255, 236, 100);
-    border: 1px solid rgb(255, 170, 34);
-    display: inline-block;
-    color: rgb(51, 51, 51);
-    font-family: Arial;
-    font-size: 15px;
-    font-weight: bold;
-    padding: 6px 24px;
-    text-decoration: none;
-    text-shadow: rgb(255, 238, 102) 0px 1px 0px;
-}
-
-.support-form input[type=submit]:hover {
-    background: linear-gradient(rgb(255, 171, 35) 5%, rgb(255, 236, 100) 100%) rgb(255, 171, 35);
-}
-
-.support-form input[type=submit]:focus {
-    outline: 0;
-}
-
-
-div.sphinxsidebar {
-    font-size: inherit;
-    line-height: inherit;
-    max-height: 100%;
-    overflow-y: auto;
-}
-
-#sidebartoc li {
     margin-top: 0.75ex;
-    margin-bottom: 0.75ex;
-}
-
-#sidebartoc ul {
-    list-style: none !important;
-}
-
-#sidebartoc a[href]:hover {
-    color: red;
-}
-
-
-.green {
-    color: green;
-}
-
-.cyan {
-    color: blue;
-}
-
-.env {
-    font-style: italic;
-}
-
-.italic {
-    font-style: italic;
-}
-
-.bold {
-    font-weight: bold;
-}
-
-.title {
-    font-size: larger;
-    font-weight: bold
 }