Today, we begin our journey into adaptive web design. Our goal is to create websites that adapt to a multitude of screen sizes.

Adaptive design involves the use of static layout designs that are tailored to suit different screen sizes. This stands in stark contrast to responsive design, which adjusts the layout fluidly to accommodate any screen size.

Consider the example of reading an eBook on various devices. The layout of the book intuitively adapts to different screen sizes, ensuring an optimal reading experience. This is the essence of adaptive design — it prioritizes usability and is focus-driven, ensuring that website visitors can navigate with ease, read text without straining, and interact with elements effortlessly.

The layout of a website can significantly differ depending on whether it's being viewed on desktops, tablets, or mobile devices.

• When viewed on desktops, both the content and the navigation menu can comfortably coexist side by side.
• On tablets, designers often resort to a simplified navigation approach using the hamburger (☰) menus, which expand when clicked.
• On mobile devices, due to the stringent space constraints, minimalism takes center stage in layout design.

We utilize the capabilities of HTML and CSS to ensure seamless adaptive navigation.

<!-- A simple navigation list example -->
<nav>
  <ul>
    <li><a href="#home">Home</a></li>
    <li><a href="#about">About</a></li>
    <li><a href="#contact">Contact</a></li>
  </ul>
</nav>

In this piece of code, we're using a navigation (<nav>) element housing an unordered list (<ul>) of links (<a>). This list, coupled with the appropriate use of CSS, adapts with ease to a wide range of screen sizes.

Dynamic menus, such as dropdowns and toggles, add an element of interactivity to website navigation. This interactivity is made possible by using CSS for design purposes and JavaScript for adding interactive elements.

<!-- An example of a simple dropdown menu -->
<div class="dropdown">
  <button class="dropdown-button">Menu</button>
  <div class="dropdown-content">
    <a href="#">Option 1</a>
    <a href="#">Option 2</a>
    <a href="#">Option 3</a>
  </div>
</div>

<!-- The accompanying CSS for the dropdown menu -->
<style>
.dropdown-content {
  display: none;
  position: absolute;
}
.dropdown:hover .dropdown-content {
  display: block;
}
</style>

In this code snippet, the dropdown menu is made invisible by default using CSS. Upon hovering over the menu, its items are revealed. By implementing JavaScript to enhance this design layout, we can significantly increase the level of dynamism and interactivity in the dropdown menu.