How to Style a To-Do List with Only CSS (No JavaScript)

In the last tutorial, we built a perfectly semantic to-do list using only HTML. It's functional, but it looks a bit plain. What if we want to make it look great and add interactive states, like a strikethrough on completed items? You don't need JavaScript for that. This tutorial will show you how to style your entire to-do list using only CSS.

We'll use the power of CSS pseudo-selectors like :checked and pseudo-elements like ::before to create a beautiful, custom, and interactive list.

The Starting Point: Our HTML

First, we need our clean, semantic HTML. This is the same structure from our previous HTML-only tutorial. The CSS we write will target these specific tags.

<form>
  <fieldset>
    <legend>My Daily Tasks</legend>
    
    <div class="task-item">
      <input type="checkbox" id="task1" name="task1">
      <label for="task1">Finish this CSS tutorial</label>
    </div>
    
    <div class="task-item">
      <input type="checkbox" id="task2" name="task2">
      <label for="task2">Learn about the :checked selector</label>
    </div>
    
    <div class="task-item">
      <input type="checkbox" id="task3" name="task3">
      <label for="task3">Build a custom checkbox</label>
    </div>
    
  </fieldset>
</form>

    

Part 1: Basic List Styling

Let's start by styling the container. We'll style the <fieldset>, <legend>, and each .task-item div to give our list a clean, modern look.

body {
  background-color: #111827;
  color: #E5E7EB;
  font-family: sans-serif;
  display: grid;
  place-items: center;
  min-height: 100vh;
}

form {
  width: 90%;
  max-width: 400px;
}

fieldset {
  border: 2px solid #374151;
  border-radius: 8px;
  padding: 20px;
}

legend {
  font-size: 1.5rem;
  font-weight: bold;
  padding: 0 10px;
  color: #F9FAFB;
}

.task-item {
  display: block;
  margin-bottom: 12px;
  position: relative;
}

label {
  font-size: 1.125rem;
  line-height: 1.5;
  cursor: pointer;
}

    

Part 2: The "Magic" - Styling the Checked State

This is the key to our CSS-only interactivity. We can use the :checked pseudo-class to detect when the checkbox is clicked. Then, using the adjacent sibling selector (+), we can apply styles to the <label> that comes right after it.

input[type="checkbox"]:checked + label {
  text-decoration: line-through;
  color: #6B7280;
}

    

Just like that, clicking the checkbox will now add a strikethrough to the text, with no JavaScript involved!

(Advanced) Part 3: Creating Custom Checkboxes

The default browser checkboxes are small and ugly. Let's hide them and create our own custom-styled checkbox using pseudo-elements.

/* 1. Hide the original checkbox */
input[type="checkbox"] {
  opacity: 0;
  position: absolute;
  width: 0;
  height: 0;
}

/* 2. Adjust label padding to make space for our box */
label {
  padding-left: 35px; /* 25px box + 10px margin */
}

/* 3. Create the custom box using ::before */
label::before {
  content: '';
  position: absolute;
  left: 0;
  top: 2px;
  width: 22px;
  height: 22px;
  border: 2px solid #6B7280;
  border-radius: 4px;
  background-color: #1F2937;
  transition: all 0.2s ease;
}

/* 4. Style the box when the (hidden) input is checked */
input[type="checkbox"]:checked + label::before {
  background-color: #3B82F6;
  border-color: #3B82F6;
}

/* 5. Create the checkmark using ::after */
label::after {
  content: '';
  position: absolute;
  left: 9px;
  top: 6px;
  width: 6px;
  height: 12px;
  border: solid white;
  border-width: 0 3px 3px 0;
  transform: rotate(45deg);
  opacity: 0;
  transition: opacity 0.2s ease;
}

/* 6. Show the checkmark when the input is checked */
input[type="checkbox"]:checked + label::after {
  opacity: 1;
}

/* 7. Add a focus state for accessibility */
input[type="checkbox"]:focus + label::before {
  box-shadow: 0 0 0 3px #3B82F680;
}