sass: toc fixed width layout error

sass/src/_toc.scss

@@ -3,13 +3,17 @@
     top: 1rem;
     box-sizing: border-box;
     margin-right: 1.25em;
-    height: calc(120vh - 1rem);
+    height: calc(110vh - 1rem);
+    overflow-y: scroll;
+    overflow-x: hidden;
     margin-left: 1em;
+    width: 250px;
     &-ul {
         position: sticky;
         border-left: 3px solid;
         padding-left: 0;
         border-color: $dark2;
+        max-width: 100%;
     }
     &-li {
         position: relative;