- Add Step Progress Bar.

- Prefix partials with `_`.

scss/elements/_sidebar.scss

@@ -0,0 +1,89 @@
+#wrapper {
+  display: flex;
+}
+
+.sidebar {
+  display: flex;
+  flex-direction: column;
+  flex-shrink: 0;
+
+  min-height: 100vh;
+  width: 200px;
+  padding: 5px 10px;
+
+  background-color: $white;
+
+  transition: none;
+
+  &-brand {
+    margin: 10px;
+    font-size: 1.125rem;
+    text-decoration: none;
+
+    &:hover {
+      text-decoration: none;
+    }
+  }
+
+  &-header {
+    margin: 10px 10px 5px;
+    font-weight: bold;
+    color: $secondary;
+  }
+
+  &-link {
+    padding: 10px 10px;
+    border-radius: 5px;
+    color: $secondary;
+    text-decoration: none;
+
+    &:hover {
+      color: $primary;
+      background-color: $primary-lightest;
+      text-decoration: none;
+    }
+  }
+
+  &-btn-collapse {
+    margin-top: 10px;
+  }
+
+  .sidebar-collapsed-shown {
+    display: none;
+  }
+}
+
+.sidebar-collapsed {
+  width: 60px;
+  padding: 5px 5px;
+  overflow-y: overlay;
+
+  transition: width 0.25s;
+
+  .sidebar-brand {
+    text-align: center;
+
+    span {
+      display: none;
+    }
+  }
+
+  .sidebar-header {
+    display: none;
+  }
+
+  .sidebar-link {
+    padding: 10px 15px;
+
+    span {
+      display: none;
+    }
+  }
+
+  .sidebar-collapsed-hidden {
+    display: none;
+  }
+  .sidebar-collapsed-shown {
+    display: inline;
+  }
+}