Moved from Sass to CSS with custom properties, allowing for dynamic theme changes.

src/web/stylesheets/components/_list.css

@@ -0,0 +1,43 @@
+/**
+ * Operation list styles
+ *
+ * @author n1474335 [n1474335@gmail.com]
+ * @copyright Crown Copyright 2017
+ * @license Apache-2.0
+ */
+
+.op-list {
+    list-style-type: none;
+    margin: 0;
+    padding: 0;
+}
+
+.category-title {
+    display: block;
+    padding: 10px;
+    background-color: var(--secondary-background-colour);
+    border-bottom: 1px solid var(--secondary-border-colour);
+    font-weight: var(--title-weight);
+}
+
+.category-title[href='#catFavourites'] {
+    border-bottom-color: var(--primary-border-colour);
+}
+
+.category-title[aria-expanded=true] {
+    border-bottom-color: var(--primary-border-colour);
+}
+
+.category-title.collapsed {
+    border-bottom-color: var(--secondary-border-colour);
+}
+
+.category-title:hover {
+    color: var(--op-list-operation-font-colour);
+}
+
+.category {
+    margin: 0 !important;
+    border-radius: 0 !important;
+    border: none;
+}