diff --git a/app.js b/app.js
index ab737a6002..e07e141161 100644
--- a/app.js
+++ b/app.js
@@ -1,195 +1,167 @@
-//Document is the DOM can be accessed in the console with document.window.
-// Tree is from the top, html, body, p etc.
-
-//Problem: User interaction does not provide the correct results.
-//Solution: Add interactivity so the user can manage daily tasks.
-//Break things down into smaller steps and take each step at a time.
-
-
-// Event handling, user interaction is what starts the code execution.
-
-var taskInput=document.getElementById("new-task");//Add a new task.
-var addButton=document.getElementsByTagName("button")[0];//first button
-var incompleteTaskHolder=document.getElementById("incompleteTasks");//ul of #incompleteTasks
-var completedTasksHolder=document.getElementById("completed-tasks");//completed-tasks
-
-
-//New task list item
-var createNewTaskElement=function(taskString){
-
-    var listItem=document.createElement("li");
-
-    //input (checkbox)
-    var checkBox=document.createElement("input");//checkbx
-    //label
-    var label=document.createElement("label");//label
-    //input (text)
-    var editInput=document.createElement("input");//text
-    //button.edit
-    var editButton=document.createElement("button");//edit button
-
-    //button.delete
-    var deleteButton=document.createElement("button");//delete button
-    var deleteButtonImg=document.createElement("img");//delete button image
-
-    label.innerText=taskString;
-    label.className='task';
-
-    //Each elements, needs appending
-    checkBox.type="checkbox";
-    editInput.type="text";
-    editInput.className="task";
-
-    editButton.innerText="Edit"; //innerText encodes special characters, HTML does not.
-    editButton.className="edit";
-
-    deleteButton.className="delete";
-    deleteButtonImg.src='./remove.svg';
-    deleteButton.appendChild(deleteButtonImg);
-
-
-    //and appending.
-    listItem.appendChild(checkBox);
-    listItem.appendChild(label);
-    listItem.appendChild(editInput);
-    listItem.appendChild(editButton);
-    listItem.appendChild(deleteButton);
-    return listItem;
+// ---------------------------
+// Get necessary DOM elements
+// ---------------------------
+const taskInput = document.getElementById("new-task");
+// In your HTML, the add button has class "todo-app__add-button"
+const addButton = document.querySelector(".todo-app__add-button");
+// ID in the HTML: "incomplete-tasks"
+const incompleteTaskHolder = document.getElementById("incomplete-tasks");
+// ID in the HTML: "completed-tasks"
+const completedTasksHolder = document.getElementById("completed-tasks");
+
+// -------------------------------------------------------
+// Function to create a new task list item (<li> element)
+// -------------------------------------------------------
+function createNewTaskElement(taskText) {
+  // Create a new <li> element with the "todo-app__item" class
+  const listItem = document.createElement("li");
+  listItem.className = "todo-app__item";
+
+  // Create a checkbox (type="checkbox") with "todo-app__checkbox" class
+  const checkBox = document.createElement("input");
+  checkBox.type = "checkbox";
+  checkBox.className = "todo-app__checkbox";
+
+  // Create a <label> with the text content and "todo-app__label" class
+  const label = document.createElement("label");
+  label.innerText = taskText;
+  label.className = "todo-app__label";
+
+  // Create an <input> for editing (type="text") with "todo-app__text-input" class
+  const editInput = document.createElement("input");
+  editInput.type = "text";
+  editInput.className = "todo-app__text-input";
+
+  // Create an Edit button with "todo-app__edit-button" class
+  const editButton = document.createElement("button");
+  editButton.innerText = "Edit";
+  editButton.className = "todo-app__edit-button";
+
+  // Create a Delete button with "todo-app__delete-button" class
+  const deleteButton = document.createElement("button");
+  deleteButton.className = "todo-app__delete-button";
+
+  // Add an <img> to the delete button
+  const deleteButtonImg = document.createElement("img");
+  deleteButtonImg.src = "./remove.svg";
+  deleteButtonImg.alt = "Remove";
+  deleteButton.appendChild(deleteButtonImg);
+
+  // Append all created elements into the <li>
+  listItem.appendChild(checkBox);
+  listItem.appendChild(label);
+  listItem.appendChild(editInput);
+  listItem.appendChild(editButton);
+  listItem.appendChild(deleteButton);
+
+  return listItem;
 }
 
+// -----------------------------
+// Function to add a new task
+// -----------------------------
+function addTask() {
+  // Prevent adding an empty string
+  if (!taskInput.value) return;
 
+  // Create the new <li> element
+  const listItem = createNewTaskElement(taskInput.value);
 
-var addTask=function(){
-    console.log("Add Task...");
-    //Create a new list item with the text from the #new-task:
-    if (!taskInput.value) return;
-    var listItem=createNewTaskElement(taskInput.value);
-
-    //Append listItem to incompleteTaskHolder
-    incompleteTaskHolder.appendChild(listItem);
-    bindTaskEvents(listItem, taskCompleted);
-
-    taskInput.value="";
-
-}
-
-//Edit an existing task.
-
-var editTask=function(){
-    console.log("Edit Task...");
-    console.log("Change 'edit' to 'save'");
-
-
-    var listItem=this.parentNode;
+  // Append the new task to the "incomplete tasks" list
+  incompleteTaskHolder.appendChild(listItem);
 
-    var editInput=listItem.querySelector('input[type=text]');
-    var label=listItem.querySelector("label");
-    var editBtn=listItem.querySelector(".edit");
-    var containsClass=listItem.classList.contains("editMode");
-    //If class of the parent is .editmode
-    if(containsClass){
-
-        //switch to .editmode
-        //label becomes the inputs value.
-        label.innerText=editInput.value;
-        editBtn.innerText="Edit";
-    }else{
-        editInput.value=label.innerText;
-        editBtn.innerText="Save";
-    }
-
-    //toggle .editmode on the parent.
-    listItem.classList.toggle("editMode");
-};
-
-
-//Delete task.
-var deleteTask=function(){
-    console.log("Delete Task...");
-
-    var listItem=this.parentNode;
-    var ul=listItem.parentNode;
-    //Remove the parent list item from the ul.
-    ul.removeChild(listItem);
+  // Bind event handlers (e.g., edit, delete, checkbox)
+  bindTaskEvents(listItem, markTaskCompleted);
 
+  // Clear the input field
+  taskInput.value = "";
 }
 
-
-//Mark task completed
-var taskCompleted=function(){
-    console.log("Complete Task...");
-
-    //Append the task list item to the #completed-tasks
-    var listItem=this.parentNode;
-    completedTasksHolder.appendChild(listItem);
-    bindTaskEvents(listItem, taskIncomplete);
-
+// -----------------------------
+// Function to edit a task
+// -----------------------------
+function editTask() {
+  const listItem = this.parentNode;
+  const editInput = listItem.querySelector('input[type="text"]');
+  const label = listItem.querySelector("label");
+  const editBtn = this;
+
+  // Check if <li> currently has the "todo-app__item--edit-mode" class
+  const isInEditMode = listItem.classList.contains("todo-app__item--edit-mode");
+
+  if (isInEditMode) {
+    // If already in edit mode, save the input value into the label
+    label.innerText = editInput.value;
+    editBtn.innerText = "Edit";
+  } else {
+    // If not in edit mode, switch to edit mode and populate input with label text
+    editInput.value = label.innerText;
+    editBtn.innerText = "Save";
+  }
+
+  // Toggle the edit mode class
+  listItem.classList.toggle("todo-app__item--edit-mode");
 }
 
-
-var taskIncomplete=function(){
-    console.log("Incomplete Task...");
-//Mark task as incomplete.
-    //When the checkbox is unchecked
-    //Append the task list item to the #incompleteTasks.
-    var listItem=this.parentNode;
-    incompleteTaskHolder.appendChild(listItem);
-    bindTaskEvents(listItem,taskCompleted);
+// -----------------------------
+// Function to delete a task
+// -----------------------------
+function deleteTask() {
+  const listItem = this.parentNode;
+  const ul = listItem.parentNode;
+  ul.removeChild(listItem);
 }
 
+// ------------------------------------------------------
+// Function to mark a task as completed (checkbox checked)
+// ------------------------------------------------------
+function markTaskCompleted() {
+  const listItem = this.parentNode;
+  // Move the task <li> to the completed tasks list
+  completedTasksHolder.appendChild(listItem);
 
-
-var ajaxRequest=function(){
-    console.log("AJAX Request");
+  // Re-bind events to handle "markTaskIncomplete" when checkbox is unchecked
+  bindTaskEvents(listItem, markTaskIncomplete);
 }
 
-//The glue to hold it all together.
-
-
-//Set the click handler to the addTask function.
-addButton.onclick=addTask;
-addButton.addEventListener("click",addTask);
-addButton.addEventListener("click",ajaxRequest);
+// ---------------------------------------------------------
+// Function to mark a task as incomplete (checkbox unchecked)
+// ---------------------------------------------------------
+function markTaskIncomplete() {
+  const listItem = this.parentNode;
+  // Move the task <li> back to the "Todo" list
+  incompleteTaskHolder.appendChild(listItem);
 
-
-var bindTaskEvents=function(taskListItem,checkBoxEventHandler){
-    console.log("bind list item events");
-//select ListItems children
-    var checkBox=taskListItem.querySelector("input[type=checkbox]");
-    var editButton=taskListItem.querySelector("button.edit");
-    var deleteButton=taskListItem.querySelector("button.delete");
-
-
-    //Bind editTask to edit button.
-    editButton.onclick=editTask;
-    //Bind deleteTask to delete button.
-    deleteButton.onclick=deleteTask;
-    //Bind taskCompleted to checkBoxEventHandler.
-    checkBox.onchange=checkBoxEventHandler;
+  // Re-bind events to handle "markTaskCompleted" when checkbox is checked
+  bindTaskEvents(listItem, markTaskCompleted);
 }
 
-//cycle over incompleteTaskHolder ul list items
-//for each list item
-for (var i=0; i<incompleteTaskHolder.children.length;i++){
-
-    //bind events to list items chldren(tasksCompleted)
-    bindTaskEvents(incompleteTaskHolder.children[i],taskCompleted);
+// -------------------------------------------------
+// Function to bind all event handlers for one <li>
+// -------------------------------------------------
+function bindTaskEvents(taskListItem, checkBoxHandler) {
+  const checkBox = taskListItem.querySelector('input[type="checkbox"]');
+  const editButton = taskListItem.querySelector(".todo-app__edit-button");
+  const deleteButton = taskListItem.querySelector(".todo-app__delete-button");
+
+  editButton.onclick = editTask;
+  deleteButton.onclick = deleteTask;
+  checkBox.onchange = checkBoxHandler;
 }
 
+// -----------------------------
+// Initial code execution
+// -----------------------------
 
+// Add task when the "Add" button is clicked
+addButton.addEventListener("click", addTask);
 
-
-//cycle over completedTasksHolder ul list items
-for (var i=0; i<completedTasksHolder.children.length;i++){
-    //bind events to list items chldren(tasksIncompleted)
-    bindTaskEvents(completedTasksHolder.children[i],taskIncomplete);
+// Bind existing items in the "incomplete tasks" list
+for (let i = 0; i < incompleteTaskHolder.children.length; i++) {
+  bindTaskEvents(incompleteTaskHolder.children[i], markTaskCompleted);
 }
 
-
-
-
-// Issues with usability don't get seen until they are in front of a human tester.
-
-//prevent creation of empty tasks.
-
-//Change edit to save when you are in edit mode.
\ No newline at end of file
+// Bind existing items in the "completed tasks" list
+for (let j = 0; j < completedTasksHolder.children.length; j++) {
+  bindTaskEvents(completedTasksHolder.children[j], markTaskIncomplete);
+}
diff --git a/index.html b/index.html
index ef4aa1f60c..7d7f82e843 100644
--- a/index.html
+++ b/index.html
@@ -1,19 +1,92 @@
-<html>
-<HEAD><title>Todo App</title>
-<link href='https://fonts.googleapis.com/css?family=Lato:300,400,700' rel='stylesheet' type='text/css'>
-<link rel="stylesheet" href="style.css" type="text/css" MEDIA="screen" charset="utf-8">
-</HEAD>
-<body>
-<div class="aaa"><img src="./eisenhower-matrix.jpg"><a class='more_inf' href="https://goal-life.com/page/method/matrix-eisenhower">Want more details&quest;</a></div>
-<div class="centered-main-page-element"><p id='topSectionForAddingElementToList'><label for="new-task">Add Item</label><div class="task-row-wrapper"><input id='new-task'class="task" type="text"><button>Add</button></div>
-</p><h3>Todo</h3>
-<ul id='incompleteTasks'>
-<li><input type='checkbox'><label class="task">Pay Bills</label><input type="text" class="task"><button class="edit">Edit</button><button class="delete"><img src="./remove.svg"></button></li>
-<li class="editMode"><input type="checkbox"><label class="task">Go Shopping</label><input type="text" value="Go Shopping" class="task"><button class='edit'>Save</button><button class="delete"><img src="./remove.svg"></button></li>
-</ul><h3>Completed</h3><ul id="completed-tasks"><li><input type="checkbox" checked><label class="task">See the Doctor</label><input type="text" class="task"><button class="edit">Edit</button><button class="delete"><img src="./remove.svg"></button>
-</li>
-</ul>
-</div>
-<script type="text/javascript" SRC="app.js"></script>
-</body>
-</html>
\ No newline at end of file
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <title>Todo App</title>
+    <link
+      href="https://fonts.googleapis.com/css?family=Lato:300,400,700"
+      rel="stylesheet"
+    />
+    <link rel="stylesheet" href="style.css" />
+  </head>
+  <body>
+    <header class="matrix-info">
+      <img
+        src="./eisenhower-matrix.jpg"
+        alt="Eisenhower matrix example"
+        class="matrix-info__image"
+      />
+      <a
+        class="matrix-info__link"
+        href="https://goal-life.com/page/method/matrix-eisenhower"
+      >
+        Want more details?
+      </a>
+    </header>
+
+    <main class="todo-app">
+      <!-- Section for adding a new task -->
+      <section class="todo-app__new-task">
+        <label class="todo-app__new-task-label" for="new-task">
+          Add Item
+        </label>
+        <div class="todo-app__new-task-row">
+          <input
+            id="new-task"
+            type="text"
+            class="todo-app__input"
+            placeholder="What do you need to do?"
+          />
+          <button class="todo-app__add-button">Add</button>
+        </div>
+      </section>
+
+      <!-- Section for uncompleted tasks -->
+      <section class="todo-app__section">
+        <h2 class="todo-app__title">Todo</h2>
+        <ul id="incomplete-tasks" class="todo-app__list">
+          <li class="todo-app__item">
+            <input type="checkbox" class="todo-app__checkbox" />
+            <label class="todo-app__label">Pay Bills</label>
+            <input type="text" class="todo-app__text-input" />
+            <button class="todo-app__edit-button">Edit</button>
+            <button class="todo-app__delete-button">
+              <img src="./remove.svg" alt="Remove" />
+            </button>
+          </li>
+          <li class="todo-app__item todo-app__item--edit-mode">
+            <input type="checkbox" class="todo-app__checkbox" />
+            <label class="todo-app__label">Go Shopping</label>
+            <input
+              type="text"
+              value="Go Shopping"
+              class="todo-app__text-input"
+            />
+            <button class="todo-app__edit-button">Save</button>
+            <button class="todo-app__delete-button">
+              <img src="./remove.svg" alt="Remove" />
+            </button>
+          </li>
+        </ul>
+      </section>
+
+      <!-- Section for completed tasks -->
+      <section class="todo-app__section">
+        <h2 class="todo-app__title">Completed</h2>
+        <ul id="completed-tasks" class="todo-app__list">
+          <li class="todo-app__item todo-app__item--completed">
+            <input type="checkbox" class="todo-app__checkbox" checked />
+            <label class="todo-app__label">See the Doctor</label>
+            <input type="text" class="todo-app__text-input" />
+            <button class="todo-app__edit-button">Edit</button>
+            <button class="todo-app__delete-button">
+              <img src="./remove.svg" alt="Remove" />
+            </button>
+          </li>
+        </ul>
+      </section>
+    </main>
+
+    <script src="app.js"></script>
+  </body>
+</html>
diff --git a/style.css b/style.css
index ab36227705..41d7b0b984 100644
--- a/style.css
+++ b/style.css
@@ -1,148 +1,155 @@
-/* Basic Style */
+/* Global styles */
 body {
-    background-color: #f8f8f8;
-    color: #333;
-    font-family: Lato, sans-serif;
-}
-.aaa {
-    width: 500px;
-    margin: 0 auto;
-    display: block;
-    text-align: right;
+  margin: 0;
+  padding: 0;
+  background-color: #f8f8f8;
+  color: #333;
+  font-family: Lato, sans-serif;
 }
-.aaa img {
-    width: 100%;
-}
-.aaa .more_inf {
-    font-family: fantasy, cursive;
-}
-
-@media (max-width:768px) {
-.aaa { text-align: center;
-}
-}
-.centered-main-page-element {
-    display: block;
-    width: 500px;
-    margin: 0 auto 0;
-}
-.task {
-    width: 56%;
-    display: inline-block;
-    flex-grow: 1
-}
-.task-row-wrapper {
-    display: flex;
+
+/* Hat with matrix */
+.matrix-info {
+  max-width: 500px;
+  margin: 0 auto;
+  text-align: right;
+  padding: 1rem;
 }
-ul {
-    margin:0;
-    padding: 0px;
+
+.matrix-info__image {
+  width: 100%;
+  height: auto;
+  display: block;
 }
-li, h3 {
-    list-style:none;
+
+.matrix-info__link {
+  display: inline-block;
+  margin-top: 0.5rem;
+  font-family: fantasy, cursive; /* If desired, we leave */
+  color: #333;
+  text-decoration: none;
 }
-input,button{
-    outline:none;
+
+.matrix-info__link:hover {
+  text-decoration: underline;
 }
-button {
-    background: none;
-    border: 0px;
-    color: #888;
-    font-size: 15px;
-    width: 60px;
-    font-family: Lato, sans-serif;
-    cursor: pointer;
+
+/* Main Application */
+.todo-app {
+  max-width: 500px;
+  margin: 0 auto;
+  padding: 1rem;
 }
-button:hover {
-    color: #3a3A3a;
+
+/* Block for adding a new task */
+.todo-app__new-task {
+  margin-bottom: 2rem;
 }
-/* Heading */
-h3,
-label[for='new-task'] {
-    color: #333;
-    font-weight: 700;
-    font-size: 15px;
-    border-bottom: 2px solid #333;
-    padding: 30px 0 10px;
-    margin: 0;
-    text-transform: uppercase;
+
+.todo-app__new-task-label {
+  display: block;
+  margin-bottom: 0.5rem;
+  font-weight: bold;
+  text-transform: uppercase;
 }
-input[type="text"] {
-    margin: 0;
-    font-size: 18px;
-    line-height: 18px;
-    height: 21px;
-    padding: 0 9px;
-    border: 1px solid #dDd;
-    background: #FFF;
-    border-radius: 6px;
-    font-family: Lato, sans-serif;
-    color: #888;
+
+.todo-app__new-task-row {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
 }
-input[type="text"]:focus {
-    color: #333;
+
+/* Universal elements */
+.todo-app__input,
+.todo-app__text-input {
+  width: 100%;
+  padding: 0.5rem;
+  border: 1px solid #ddd;
+  border-radius: 4px;
+  font-size: 1rem;
+  color: #888;
+  box-sizing: border-box;
 }
 
-/* New Task */
-label[for='new-task'] {
-    display: block;
-    margin: 0 0 20px;
+.todo-app__input:focus,
+.todo-app__text-input:focus {
+  color: #333;
+  outline: 1px solid #333;
 }
-input#new-task {
-    width: 318px;
+
+.todo-app__add-button,
+.todo-app__edit-button,
+.todo-app__delete-button {
+  background: none;
+  border: 0;
+  color: #888;
+  font-size: 1rem;
+  cursor: pointer;
+  padding: 0.5rem 1rem;
 }
 
-/* Task list */
-li {
-    overflow: hidden;
-    padding: 20px 0;
-    border-bottom: 1px solid #eee;
+.todo-app__add-button:hover,
+.todo-app__edit-button:hover,
+.todo-app__delete-button:hover {
+  color: #555;
+}
 
-    display: flex;
-    justify-content: space-between;
-    align-items: center;
+/* Section Headings */
+.todo-app__section {
+  margin-bottom: 2rem;
 }
-li > * {
-    vertical-align: middle;
+
+.todo-app__title {
+  margin: 0 0 1rem;
+  font-weight: bold;
+  text-transform: uppercase;
+  border-bottom: 2px solid #333;
+  padding-bottom: 0.5rem;
 }
 
-li > input[type="checkbox"] {
-    margin: 0 10px;
+/* List of tasks */
+.todo-app__list {
+  list-style: none;
+  margin: 0;
+  padding: 0;
 }
-li > label {
-    padding-left: 10px;
-    box-sizing: border-box;
-    font-size: 18px;
-    width: 226px;
+
+.todo-app__item {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  padding: 1rem 0;
+  border-bottom: 1px solid #eee;
 }
-li >    input[type="text"] {
-    width: 226px
+
+.todo-app__label {
+  flex-grow: 1;
+  font-size: 1rem;
 }
-button.delete img {
-    height: 2em;
-    transform: rotateZ(45deg);
-    transition: transform 200ms ease-in;
+
+.todo-app__checkbox {
+  margin-right: 0.5rem;
 }
-button.delete img:hover {
-    transform: rotateZ(0);
+
+.todo-app__delete-button img {
+  width: 1.5rem;
+  height: 1.5rem;
+  transition: transform 0.2s ease-in;
 }
 
-/* Completed */
-ul#completed-tasks label {
-    text-decoration: line-through
-    color: #888;
+.todo-app__delete-button:hover img {
+  transform: rotate(45deg);
 }
 
-/* Edit Task */
-ul li input[type=text] {
-    display:none
+/* Modifiers */
+.todo-app__item--edit-mode .todo-app__label {
+  display: none;
 }
 
-ul li.editMode input[type=text] {
-    display:inline-block;
-    width:224px
+.todo-app__item--edit-mode .todo-app__text-input {
+  display: block;
 }
 
-ul li.editMode label {
-    display:none;
-}
\ No newline at end of file
+.todo-app__item--completed .todo-app__label {
+  text-decoration: line-through;
+  color: #888;
+}