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                <article id="content">
  <p id="fakescroll"><i></i></p>
  <h1>HTML Ipsum Presents</h1>

    <aside id="note1"><b>senectus</b> Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue.</aside>

    <p><strong>Pellentesque habitant morbi tristique</strong> senectus<a href="#note1">(*)</a> et netus et malesuada fames ac turpis egestas. Vestibulum tortor quam, feugiat vitae, ultricies eget, tempor sit amet, ante. Donec eu libero sit amet quam egestas semper. <em>Aenean ultricies mi vitae est.</em> Mauris placerat eleifend leo. Quisque sit amet est et sapien ullamcorper pharetra. Vestibulum erat wisi, condimentum sed, <code>commodo vitae</code>, ornare sit amet, wisi. Aenean fermentum, elit eget tincidunt condimentum, eros ipsum rutrum orci, sagittis tempus lacus enim ac dui. <a href="#">Donec non enim</a> in turpis pulvinar facilisis. Ut felis.</p>

  <h2>Header Level 2</h2>

    <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
    <li>Aliquam tincidunt mauris eu risus.</li>
      <p>Lorem ipsum dolor sit amet<a href="#note2">(*)</a>, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est.</p>
    <aside id="#note2" class="right">
      Hello , another note.<br>too long ?<br>too long ?<br>too long ?<br>too long ?<br>too long ?<br>too long ?<br>too long ?

  <h3>Header Level 3</h3>

    <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
    <li>Aliquam tincidunt mauris eu risus.</li>

#header h1 a {
  display: block;
  width: 300px;
  height: 80px;


                * {
  margin: 0;
  padding: 0;
  box-sizing: border-box;

body {
  min-width: 1200px;
  position: relative;
#content {
  height: 100vh;
  overflow: auto;
article {
  background: linear-gradient(
      to right,
      blue 2px,
      lightgray 2px,
      lightgray calc(100% - 2px),
      blue calc(100% - 2px)
    no-repeat center / 820px 100%;

section {
  display: grid;
  grid-template-columns: 1fr 800px 1fr;
  gap: 0px;
section {
  grid-column: 1 / span 3;
article > :not(aside):not(section),
section > :not(aside) {
  grid-column: 2;
  padding:0.15em 1em;
aside {
  grid-column: 1;
  height: 0;
  min-height: 100%;
  overflow: auto;
  border: solid;
  margin: 0 1em 0 auto;
aside.right {
  grid-column: 3;
  margin: 0 auto 0 2.4em;
#fakescroll {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  margin: 0;
  transform: translate(375px, 0);
  overflow-y: auto;
  width: 1em;
  height: 100vh;
  box-sizing: border-box; 
#fakescroll i {
  display: block;
  height: 100%;



                window.onload = resetH;
window.onresize = resetH;

function resetH() {
  let scrollH = document.querySelector("#content").scrollHeight;// on recupere la hauteur de #content
  let myScroll = document.querySelector("#fakescroll i");//on recupere l'element qui va etre redimensionné pour déclanché l'apparition de la barre de scroll = scrollH + "px";// on ajoute un padding a sa hauteur initiale pour l'étiré

// synchro des scrolls
let s1 = document.querySelector("#content");
let s2 = document.querySelector("#fakescroll");
function select_scroll_1(e) {
  s2.scrollTop = s1.scrollTop;
function select_scroll_2(e) {
  s1.scrollTop = s2.scrollTop;
s1.addEventListener("scroll", select_scroll_1, false);
s2.addEventListener("scroll", select_scroll_2, false);