add styling

assets/stylesheets/pages/_threejs.scss

@@ -0,0 +1,47 @@
+._threejs {
+    // Code blocks
+    pre, code {
+      background-color: #f5f5f5;
+      border-radius: 3px;
+      padding: 0.2em 0.4em;
+    }
+    pre {
+      padding: 1em;
+      margin: 1em 0;
+      overflow: auto;
+      code {
+        background: none;
+        padding: 0;
+      }
+    }
+    // Links
+    a {
+      color: #049EF4;
+      text-decoration: none;
+      &:hover {
+        text-decoration: underline;
+      }
+    }
+    // Headings
+    h2 {
+      margin-top: 2em;
+      padding-bottom: 0.3em;
+      border-bottom: 1px solid #eaecef;
+    }
+    h3 {
+      margin-top: 1.5em;
+    }
+    // Tables
+    table {
+      border-collapse: collapse;
+      margin: 1em 0;
+      width: 100%;
+    }
+    th, td {
+      border: 1px solid #dfe2e5;
+      padding: 6px 13px;
+    }
+    tr:nth-child(2n) {
+      background-color: #f6f8fa;
+    }
+  }