Image Comparison Slider in CSS Only (without using JavaScript)

In this tutorial, we will create an image comparison slider using CSS without JavaScript. We start by creating an input range slider and two divs with class names '.front' and '.back' inside a parent div with the class name '.img-before-after'. We then assign an inline CSS variable to the input range style, which is "--timeline:--_slider" with a value of "50". Next, we create CSS for the elements img-before-after, input-range, and input-slider-thumb. We also add background images for both .front and .back divs and assign the width property value to var(--width). The .back div is sent behind the .front div with a z-index and made grayscale. The final output shows the image comparison slider with a grayscale effect on the .back div.