diff --git a/admin/site/themes/afp/assets/sass/main.scss b/admin/site/themes/afp/assets/sass/main.scss
--- a/admin/site/themes/afp/assets/sass/main.scss
+++ b/admin/site/themes/afp/assets/sass/main.scss
@@ -1,1088 +1,1092 @@
 //colors
 $theme: hsl(242, 27%, 24%);
 $theme-hover: hsl(241, 26%, 36%);
 $theme-lightest: hsl(261, 36%, 86%);
 $theme-focus: #acabcf;
 $link: #0645ad;
 $link-hover: #0000ee;
 $link-visited: #42047c;
 $white: #fff;
 $lightest-grey: #f2f2f2;
 $lighter-grey: #ddd;
 $light-grey: #bbb;
 $dark-grey: #777;
 $darker-grey: #555;
 $darkest-grey: #303030;
 $black: #000;
 $black_15: rgba(0, 0, 0, 0.15);
 
 //fonts
 $sans-serif: "Open Sans", sans-serif;
 $monospace: "Consolas", monospace;
 $OpenSans: "Open Sans";
 
 $light: 300;
 $normal: 400;
 $bold: 700;
 
 $border-bottom: 2px $darker-grey solid;
 
 %code {
   font-family: $monospace;
   background-color: $lightest-grey;
   color: $darkest-grey;
 }
 
 %button {
   border: 1px solid $dark-grey;
   font-size: 1rem;
   vertical-align: middle;
   background-color: $white;
   color: $black;
   line-height: 0;
   font-family: $sans-serif;
 }
 
 %button-image {
   position: relative;
   top: 0.12em;
   left: 5px;
   padding-right: 5px;
 }
 
 %sticky {
     position: sticky;
     top: 0;
     background-color: $white;
     margin: 0;
     padding-bottom: 0.5rem;
 }
 
 @font-face {
   font-family: $OpenSans;
   font-display: swap;
   font-style: normal;
   font-weight: 300;
   src: local(""), url("/font/open-sans-v18-latin-300.woff2") format("woff2"),
   url("/font/open-sans-v18-latin-300.woff") format("woff");
 }
 
 @font-face {
   font-family: $OpenSans;
   font-display: swap;
   font-style: normal;
   font-weight: 400;
   src: local(""), url("/font/open-sans-v18-latin-regular.woff2") format("woff2"),
   url("/font/open-sans-v18-latin-regular.woff") format("woff");
 }
 
 @font-face {
   font-family: $OpenSans;
   font-display: swap;
   font-style: italic;
   font-weight: 400;
   src: local(""), url("/font/open-sans-v18-latin-italic.woff2") format("woff2"),
   url("/font/open-sans-v18-latin-italic.woff") format("woff");
 }
 
 @font-face {
   font-family: $OpenSans;
   font-display: swap;
   font-style: normal;
   font-weight: 700;
   src: local(""), url("/font/open-sans-v18-latin-700.woff2") format("woff2"),
   url("/font/open-sans-v18-latin-700.woff") format("woff");
 }
 
 @font-face {
   font-family: $OpenSans;
   font-display: swap;
   font-style: italic;
   font-weight: 700;
   src: local(""), url("/font/open-sans-v18-latin-700italic.woff2") format("woff2"),
   url("/font/open-sans-v18-latin-700italic.woff") format("woff");
 }
 
 *::selection {
   background-color: $theme;
   color: $white;
 }
 
 body {
   color: $black;
   background: $white;
   font-family: $sans-serif;
   display: grid;
   grid-template-columns: #{"max(20%, 200px)"} 1fr;
   grid-template-areas: "sidebar content";
   justify-items: center;
   margin: 0;
 }
 
 aside {
   grid-area: sidebar;
   background-color: $theme;
   width: 20vw;
   margin: 0;
   height: 100%;
   position: fixed;
   top: 0;
   left: 0;
   min-width: 200px;
   word-break: break-all;
   overflow-y: auto;
   color: $white;
 
   nav {
     display: flex;
     flex-direction: column;
     justify-content: space-between;
     height: 100vh;
   }
 
   ul {
     list-style: none;
     padding: 0;
   }
 
   li {
     padding: 0.5em 2rem;
 
     &:hover {
       background-color: $theme-hover;
     }
   }
 
   .active {
     background-color: $theme-hover;
   }
 
   div > a {
     display: block;
     text-align: center;
   }
 
   a:not(.entity_ref) {
     &:link,
     &:visited {
       color: $white;
     }
 
     &:focus {
       outline: 1px $theme-focus solid;
       outline-offset: 3.5px;
     }
   }
 
   hr {
     margin: 2rem;
     border: none;
     border-top: 2px solid $dark-grey;
   }
 }
 
 .logo {
   width: 40%;
   height: auto;
   padding: 10%;
   max-width: 160px;
 }
 
 li {
   margin: 0.25em 0;
 }
 
 header {
   border-bottom: $border-bottom;
   margin-bottom: 20px;
   padding: 0.5rem 0;
 
   > div {
     display: flex;
     justify-content: space-between;
     padding: 0.5rem 0;
   }
 
   form {
     padding: 0.5rem 0;
     float: right;
   }
 
   h1 {
     padding: 0.5rem 0;
     margin: 0;
     clear: both;
     line-height: 2.75rem;
   }
 
   #search-input {
     height: 2rem;
     padding: 7px;
     width: 175px;
   }
 
   #search-button {
     height: 2rem;
     padding: 7px;
     width: 2rem;
 
     &:hover {
       background-color: $lighter-grey;
     }
 
     &:active {
       background-color: $light-grey;
     }
   }
 
   div p {
     margin: 0;
   }
 }
 
 .content {
   grid-area: content;
   margin: 0 auto 2rem;
   width: 50vw;
   min-width: 550px;
 
   div {
     line-height: 1.35em;
     width: 100%;
 
     h1 {
       border-bottom: $border-bottom;
     }
   }
 
   > div {
     form {
       margin: 2rem auto 0;
       width: 50%;
       min-width: 290px;
       padding: 1rem 0;
     }
 
     #search-button {
       height: 2.5rem;
       width: 25%;
       min-width: 70px;
       background: $theme;
       color: $white;
       border: 1px $theme solid;
     }
 
     #search-input {
       height: 2.5rem;
       width: 75%;
     }
   }
 
   .popup {
     background: $white;
     box-shadow: 0 0 8px 0 $black_15, 0 4px 10px 0 $black_15;
     padding: 2.5rem;
     display: block;
     width: auto;
     min-width: 300px;
     max-width: 90vw;
     max-height: 75vh;
     position: fixed;
     left: 50%;
     top: 50%;
     transform: translate(-50%, -50%);
     overflow-y: auto;
   }
 
   .chart {
     min-width: 400px;
     width: 100%;
     min-height: 400px;
     max-height: 50vh;
     background: $white;
     margin: 20px auto 40px;
     border: 1px solid $black;
     position: relative;
   }
 
   .statsnumber {
     text-align: right;
     padding-right: 1rem;
   }
 
   ul {
     list-style-type: none;
   }
 
   li {
     word-break: break-all;
   }
 
   li::before {
     content: "–";
     position: absolute;
     margin-left: -1.3em;
   }
 }
 
 .entries {
   > div {
     display: grid;
     grid-template-columns: 3fr 1fr;
   }
 
   main {
     padding-right: 2%;
     max-width: 90ch;
 
     div {
       margin: 1rem 0;
     }
   }
 
   nav {
     width: 130px;
     margin-left: auto;
 
     h4 {
       color: $darker-grey;
       font-weight: $normal;
     }
   }
 }
 
 .theories {
   grid-template-columns: 20% 80%;
   justify-content: normal;
 
   .collapsible.collapsed {
     display: none;
   }
 
   .invertible.collapsed {
     transform: scale(1,-1);
   }
 
   .collapse-container.collapsed {
     .collapsible {
       display: none;
     }
     .invertible {
       transform: scale(1,-1);
     }
   }
 
   .content {
     min-width: clamp(80ch,50vw, 50vw);
     width: auto;
     max-width: 75vw;
     margin: 0 0 2rem 4vw;
   }
 
   h2 {
     @extend %sticky;
     padding-top: 0.5rem;
     border-bottom: 1px $light-grey solid;
 
     svg {
       height: 2rem;
       width: 20px;
       position: absolute;
       right: 1em;
       stroke: $dark-grey;
       transition: transform 100ms;
     }
   }
 
   main {
       > div {
           margin-bottom: 1rem;
       }
   }
 
   aside {
     word-break: normal;
     z-index: 1;
     overflow-x: hidden;
 
     .logo {
         padding-top: 2rem;
         padding-bottom: 2rem;
         width: 100px;
 
         @media (min-width: 1800px) {
             width: 150px;
         }
     }
 
     > div {
       margin-right: 1rem;
     }
 
     &:hover {
       min-width: fit-content;
       div {
         min-width: fit-content;
       }
     } 
 
     ul {
       margin-left: 1.75rem;
     }
 
     li {
       padding: 0;
 
       &:hover {
         background-color: $theme;
       }
 
       > a:hover {
         background-color: $theme-hover;
       }
 
       a {
         padding: 0.5em 0;
         display: inline-block;
         width: 100%;
       }
     }
   }
 
   @media (max-width: 875px) {
     padding: 0;
     grid-template-columns: 1fr;
 
     .content {
       min-width: 350px;
       max-width: 100vw;
       margin: 80px 0;
     }
 
     nav {
       display: none;
     }
   }
 }
 
 .links {
   button {
     display: inline-block;
     margin: 0.5rem 0;
   }
 
   a {
     display: inline-block;
     margin: 0.5rem 0;
   }
 }
 
 .popup-button:not(.entity_ref) {
   &:visited {
     color: $white;
   }
 
   &:link {
     border: none;
     padding: 0.75rem 0;
     background-color: $theme;
     color: $white;
     cursor: pointer;
     text-align: center;
     transition: background-color 200ms ease, transform 150ms ease;
     font-weight: $bold;
     font-size: 0.9rem;
     width: 130px;
   }
 
   &:active {
     transform: scale(0.98);
   }
 }
 
 a:not(.entity_ref) {
   &:link {
     color: $link;
     text-decoration: none;
     font-weight: $bold;
   }
 
   &:visited {
     color: $link-visited;
   }
 
   &:hover {
     color: $link-hover;
   }
 }
 
 h1 {
   margin: 1.5em 0 0 0;
   font-size: 2em;
   padding-bottom: 20px;
 
   span.first {
     font-size: 2.3rem;
   }
 }
 
 h2 {
   margin: 1.5em 0 0 0;
   padding: 0;
   line-height: normal;
 }
 
 h3 {
   margin: 1.5em 0 0 0;
   font-stretch: normal;
   font-size: larger;
   padding: 0;
   font-weight: $light;
 
   &:first-child {
     margin: 0.5rem 0 0 0;
   }
 }
 
 h4 {
   margin: 1.5em 0 0 0;
   margin-bottom: 0.5ex;
   font-weight: $bold;
 }
 
 .popup {
   h2 {
     margin-top: 0;
   }
 
   .close {
     position: absolute;
     width: 20px;
     height: 20px;
     top: 2rem;
     right: 2rem;
     transition: all 200ms;
     font-size: 24px;
     font-weight: $bold;
     color: $darker-grey;
     text-align: center;
 
     &:hover {
       color: $darkest-grey;
     }
   }
 }
 
 #download-popup {
   a[download] {
     display: block;
     width: 154px;
     margin: 2.5rem auto 0;
   }
 }
 
 .year {
   @extend %sticky;
   padding-top: 2rem;
   border-bottom: $border-bottom;
 }
 
 img {
   max-width: 90%;
 }
 
 pre {
   @extend %code;
   padding: 1rem;
   overflow: auto;
 
   &.bibtex {
     white-space: pre;
     border-width: thin;
     border-style: solid;
   }
 
   &.code {
     white-space: pre;
     padding: 10px 2px;
   }
 }
 
 code {
   padding: 1px 2px 2px;
   @extend %code;
 }
 
 blockquote {
   border: 2px solid $lighter-grey;
   padding: 1rem 2rem;
   margin: auto 0;
 }
 
 tr:nth-child(even) {
   background-color: $lightest-grey;
 }
 
 .nobr {
   white-space: nowrap;
 }
 
 .large-top-margin {
   margin-top: 48px;
 }
 
 .search-page {
   > div {
     display: grid;
     grid-template-columns: 3fr #{"max(25%, 175px)"};
     grid-template-rows: 150px 1fr;
     grid-template-areas:
       "search search"
       "entries sidebar";
   }
 
   form {
     grid-area: search;
   }
 
   #search-main {
     grid-area: entries;
     padding-right: 2rem;
     box-sizing: border-box;
   }
 
   #search-results {
     > div {
       position: relative;
       margin: 1.5rem 0;
       border-bottom: 2px $lighter-grey solid;
       padding-bottom: 1.5rem;
     }
 
     div + div {
       margin-top: 1rem;
     }
 
     .title,
     .subtitle {
       display: flex;
       justify-content: space-between;
       align-items: center;
     }
 
     .subtitle {
       color: $dark-grey;
       font-size: 0.875em;
 
       > p {
         margin: 0;
       }
     }
 
     a[download] {
       padding: 5px 7.5px;
       flex-shrink: 0;
       margin-left: 1em;
     }
   }
 
   #search-sidebar {
     grid-area: sidebar;
   }
 }
 
 a[download] {
   display: inline-block;
   color: $black;
   height: 22px;
   padding: 4px 7px;
   @extend %button;
 
   &:focus {
     outline: none;
     box-shadow: 0 0 0 2px #c5c4ddbb;
   }
 
   &:hover,
   &:active {
     background-color: $light-grey;
     color: $black;
   }
   &:after {
     content: url("/images/download.svg");
     @extend %button-image;
   }
 }
 
 .entry {
   display: flex;
   align-items: center;
   margin-top: 1.35rem;
 
   a[download] {
     position: absolute;
     top: 0;
     right: 0;
   }
 
   .date {
     text-align: right;
     width: 15%;
     min-width: 6ch;
     font-family: $monospace;
   }
 
   h5 {
     font-size: initial;
     display: initial;
   }
 }
 
 .form-container {
   width: 290px;
   text-align: left;
 }
 
 #search-input {
   @extend %button;
   border-right: none;
   font-family: $sans-serif;
   padding: 0.5em;
 }
 
 #search-button:not(.entity_ref) {
   @extend %button;
   cursor: pointer;
 
   &:focus {
     outline: none;
     box-shadow: 0 0 0 2px #c5c4ddbb;
   }
 
   img {
     max-width: 1rem;
   }
 }
 
+.entity_def.active {
+  background-color: $theme-focus;
+}
+
 button {
   @extend %button;
   height: 2rem;
   padding: 7px;
   font-weight: $bold;
   cursor: pointer;
 
   &:hover {
     background-color: $lighter-grey;
   }
 
   &:active {
     background-color: $light-grey;
   }
 
   &:focus {
     outline: none;
     box-shadow: 0 0 0 2px #c5c4ddbb;
   }
 }
 
 button[copy] {
   &:after {
     content: url("/images/copy.svg");
     @extend %button-image;
   }
 }
 
 #search-input-autocomplete-list {
   width: 214px;
   position: absolute;
   margin-bottom: 24px;
   padding: 8px 0;
   background-color: $white;
   border: 1px solid $lighter-grey;
   box-shadow: 0 2px 4px $black_15;
   z-index: 1;
 
   div {
     width: auto;
     padding: 8px 12px;
     line-height: 16px;
     cursor: pointer;
 
     &:hover {
       background: $lighter-grey;
     }
   }
 }
 
 .autocomplete-active {
   background: $lighter-grey;
 }
 
 .item-text {
   width: 85%;
 }
 
 .date {
   color: $darker-grey;
   font-size: 14px;
 }
 
 .overlay {
   position: fixed;
   top: 0;
   bottom: 0;
   left: 0;
   right: 0;
   background: $black_15;
   transition: opacity 200ms;
   visibility: hidden;
   opacity: 0;
 
   .cancel {
     position: absolute;
     width: 100%;
     height: 100%;
     cursor: pointer;
   }
 
   &:target {
     visibility: visible;
     opacity: 1;
   }
 }
 
 .status-ok {
   background-color: #00FF99;
   padding: 8px;
 }
 
 .status-skipped {
   background-color: #FFFF99;
   padding: 8px;
 }
 
 .status-failed {
   background-color: #DD2222;
   padding: 8px;
 }
 
 iframe {
   width: 100%;
   height: 90vh;
 }
 
 .loader {
   margin: 24px 24px 0 0;
   height: 6px;
   position: relative;
   display: block;
   background-color: $theme;
   border-radius: 4px;
   overflow: hidden;
 
   .animation {
     background-color: $light-grey;
 
     &:before {
       content: '';
       position: absolute;
       background-color: inherit;
       top: 0;
       left: 0;
       bottom: 0;
       will-change: left, right;
       animation: loader 2s linear infinite;
     }
   }
 }
 
 @keyframes loader {
   0% {
     left: -20%;
     right: 100%;
   }
   100% {
     left: 100%;
     right: -20%;
   }
 }
 
 #menu-toggle {
   input,
   label {
     display: none;
   }
 
   > .logo-link, img[alt="Search"] {
     display: none;
   }
 
   > #menu {
     box-shadow: 0 .5rem 1rem rgba(0,0,0,.15);
   }
 
   form {
     display: none;
   }
 }
 
 @media (max-width: 650px) {
   .content {
     width: 90%;
     min-width: 350px;
   }
 
   .search-page {
     > div {
       display: grid;
       grid-template-columns: 1fr;
       grid-template-rows: 150px auto auto ;
       grid-template-areas:
         'search'
         'sidebar'
         'entries';
     }
   }
 }
 
 @media (max-width: 875px) {
   body {
     grid-template-columns: 1fr;
     grid-template-areas: 'content';
   }
 
   aside {
     height: 4rem;
     width: 100vw;
     overflow-y: visible;
     z-index: 1;
   }
 
   header {
     form {
       display: none;
     }
   }
 
   .content {
     margin-top: 80px;
   }
 
   .entries {
     > div {
       display: grid;
       grid-template-rows: auto auto;
       grid-template-columns: 1fr;
     }
 
     nav {
       margin-left: 0;
     }
   }
 
     
   .large-top-margin {
     margin-top: 0;
   }
 
   #banner {
     left: 0;
     width: 100vw;
     height: 75px;
 
     p {
       line-height: normal;
       margin: 1rem;
     }
   }
 
   #menu-toggle {
     background: $theme;
     display: block;
     position: relative;
     top: 0;
     left: 0;
     z-index: 1;
     height: 80px;
     user-select: none;
     width: 100vw;
     a {
       text-decoration: none;
       transition: color 0.3s ease;
     }
     .logo-link {
       height: 3rem;
       max-width: 50vw;
       top: 1rem;
       left: 0;
       right: 0;
       margin-left: auto; 
       margin-right: auto;
 
 
       img {
         padding: 0;
         height: 3rem;
         object-fit: contain;
       }
     }
 
     .logo-link, input, label, a[href="/search"] {
       display: block;
       position: absolute;
       z-index: 2;
     }
 
     input, label, a[href="/search"] {
       width: 24px;
       height: 24px;
       top: 28px;
     }
 
     input,label { 
       left: 28px;
       cursor: pointer;
     }
 
     a[href="/search"] {
       right: 28px;
       filter: invert(1);
     }
 
     a[href="/search"] img, label img {
       width: 100%;
     }
 
     input {
       opacity: 0;
       &:checked {
         ~ nav {
           left: 0;
         }
       }
     }
     
     label span {
         display: none;
     }
   }
   #menu {
     height: 100vh;
     position: absolute;
     top: 0;
     left: 0;
     padding-top: 80px;
     box-sizing: border-box;
     min-width: 200px;
     width: 50vw;
     max-width: 350px;
     min-height: 355px;
     background: $theme;
     left: -100%;
     transition: left 0.3s ease;
 
     .logo-link {
       display: none;
     }
   }
 }
diff --git a/admin/site/themes/afp/layouts/partials/theory-navigation.html b/admin/site/themes/afp/layouts/partials/theory-navigation.html
--- a/admin/site/themes/afp/layouts/partials/theory-navigation.html
+++ b/admin/site/themes/afp/layouts/partials/theory-navigation.html
@@ -1,32 +1,32 @@
 {{- $entry_name := .File.BaseFileName -}}
 {{- $site := . -}}
 {{- $path := .Site.Params.afpUrls.html -}}
 {{- if isset .Site.Data "status" -}}
   {{- $path = .Site.Params.afpUrls.htmlDevel -}}
 {{- end -}}
 <div id="menu-toggle">
   <a href="{{- .Site.BaseURL -}}" class='logo-link'>
     <img src="{{- .Site.BaseURL -}}images/afp.png" alt='Logo of the Archive of Formal Proofs' class="logo">
   </a>
   <nav>
   <div>
     <a href="{{- .Site.BaseURL -}}">
       <img src="{{- .Site.BaseURL -}}images/afp.png" alt='Logo of the Archive of Formal Proofs'
         class="logo">
     </a>
     {{ $currentPage := . -}}
     <ul>
-      <li><a href="{{- .Site.BaseURL -}}entries/{{- $entry_name | urlize -}}">Return to entry</a></li>
+      <li><a href="{{- .Site.BaseURL -}}entries/{{- $entry_name -}}.html">Return to entry</a></li>
     </ul>
     <hr>
     <ul id="theory-navbar" class="list-group"></ul>
   </div>
   <ul>
     <li><a href="{{- $path -}}/{{- $entry_name -}}/outline.pdf">Proof
       outline</a></li>
     <li><a href="{{- $path -}}/{{- $entry_name -}}/document.pdf">Proof
       document</a></li>
     <li><a href="{{- $path -}}/{{- $entry_name -}}/session_graph.pdf">Session dependencies</a></li>
   </ul>
   </nav>
 </div>
diff --git a/admin/site/themes/afp/static/js/scroll-spy.js b/admin/site/themes/afp/static/js/scroll-spy.js
--- a/admin/site/themes/afp/static/js/scroll-spy.js
+++ b/admin/site/themes/afp/static/js/scroll-spy.js
@@ -1,130 +1,134 @@
 /**
  * Scrollspy, inspired from bootstrap. Original license:
  * --------------------------------------------------------------------------
  * Bootstrap (v5.1.3): scrollspy.js
  * Licensed under MIT (https://github.com/twbs/bootstrap/blob/main/LICENSE)
  *
  * --------------------------------------------------------------------------
  */
 
 const EVENT_SPY_ACTIVATE = 'activate.spy'
 const CLASS_ACTIVE = 'active'
 const CLASS_SPY_LINK = 'spy-link'
 
 /**
  * Class definition
  */
 
 class ScrollSpy {
-  constructor(element, target, offset = 10) {
+  constructor(element, target, offset = 0.5) {
     ScrollSpy.instance = this
     this._element = element
 
     this._offset = offset
     this._offsets = []
     this._link_ids = []
     this._active_id = null
     this._scrollHeight = 0
     this._target = target
 
     window.onscroll = () => this._process()
 
     this.refresh()
     this._process()
   }
 
   refresh() {
     this._clear()
     this._offsets = []
     this._link_ids = []
     this._scrollHeight = this._getScrollHeight()
 
     const targets = []
     for (const link of document.getElementById(this._target).getElementsByClassName(CLASS_SPY_LINK)) {
       // visible and has id
       if (link.id && !is_collapsed(link)) {
         const target_id = link.getAttribute('href').slice(1)
         const target = document.getElementById(target_id)
 
         if (target) {
           const targetBCR = target.getBoundingClientRect()
           if (targetBCR.width || targetBCR.height) {
             targets.push([targetBCR.top + window.pageYOffset, link.id])
           }
         }
       }
     }
 
     for (const item of targets.sort((a, b) => a[0] - b[0])) {
       this._offsets.push(item[0])
       this._link_ids.push(item[1])
     }
   }
 
   // Private
   _getScrollHeight() {
     return window.scrollHeight || Math.max(
       document.body.scrollHeight,
       document.documentElement.scrollHeight
     )
   }
   _process() {
-    const scrollTop = window.pageYOffset + this._offset
+    const scrollTop = window.pageYOffset + this._offset * window.innerHeight
     const scrollHeight = this._getScrollHeight()
-    const maxScroll = this._offset + scrollHeight - window.innerHeight
+    const maxScroll = this._offset * window.innerHeight + scrollHeight - window.innerHeight
 
     if (this._scrollHeight !== scrollHeight) {
       this.refresh()
     }
 
     if (scrollTop >= maxScroll) {
       const target_id = this._link_ids[this._link_ids.length - 1]
 
       if (this._active_id !== target_id) {
         this._activate(target_id)
       }
 
       return
     }
 
     if (this._active_id && scrollTop < this._offsets[0] && this._offsets[0] > 0) {
       this._clear()
       return
     }
 
     for (let i = this._offsets.length; i--;) {
       const isActiveTarget = this._active_id !== this._link_ids[i] &&
         scrollTop >= this._offsets[i] &&
         (typeof this._offsets[i + 1] === 'undefined' || scrollTop < this._offsets[i + 1])
 
       if (isActiveTarget) {
         this._activate(this._link_ids[i])
       }
     }
   }
 
   _activate(link_id) {
     this._clear()
     this._active_id = link_id
 
     const link = document.getElementById(link_id)
     if (link) {
+      const elem = document.getElementById(link.getAttribute('href').slice(1))
       link.classList.add(CLASS_ACTIVE)
+      elem.classList.add(CLASS_ACTIVE)
 
       const event = new Event(EVENT_SPY_ACTIVATE)
       event.relatedTarget = link
       window.dispatchEvent(event)
     }
   }
 
   _clear() {
     if (this._active_id) {
       const link = document.getElementById(this._active_id)
-      if (link && link.classList.contains(CLASS_ACTIVE)) {
-        link.classList.remove(CLASS_ACTIVE)
+      if (link) {
+        const elem = document.getElementById(link.getAttribute('href').slice(1))
+        if (link.classList.contains(CLASS_ACTIVE)) link.classList.remove(CLASS_ACTIVE)
+        if (elem.classList.contains(CLASS_ACTIVE)) elem.classList.remove(CLASS_ACTIVE)
       }
     }
   }
 
   static instance
 }
\ No newline at end of file