Convert site to Jekyll

- Add Jekyll configuration (_config.yml)
- Create default layout with proper HTML structure
- Extract CSS to separate file (assets/css/main.css)
- Convert index.html to Jekyll format (index.md)
- Move image to assets directory
- Add Gemfile for Jekyll dependencies
- Backup original index.html

The site now uses Jekyll static site generator while maintaining
the same visual appearance and functionality as the original.

assets/css/main.css

@@ -0,0 +1,45 @@
+/* Main styles for resist.is */
+body {
+    background-color: black;
+    margin: 0;
+    padding: 0;
+    font-family: Arial, sans-serif;
+}
+
+p {
+    color: white;
+}
+
+div {
+    max-width: 700px;
+    margin-left: auto;
+    margin-right: auto;
+}
+
+.main-container {
+    text-align: center;
+}
+
+.content-wrapper {
+    text-align: center;
+}
+
+.bold-text {
+    font-weight: bold;
+    margin: 0;
+}
+
+.no-margin {
+    margin: 0;
+}
+
+.link {
+    text-align: center;
+    color: royalblue;
+    text-decoration: none;
+}
+
+.link:hover {
+    text-decoration: underline;
+}
+