CSS Mask Div with Another Div- Complete Guide

🔍 What Is CSS Masking?

CSS masking is the process of applying a mask to an element to control which parts of it are visible. The mask can be:

• A solid color block (like another
  )
• An image
• An SVG shape

This technique is commonly used to create layered visual effects, highlight content, or craft unique UI elements without relying on image editing software.

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🎯 Why Use CSS Masking?

• Create dynamic visuals without heavy images
• Add interactive reveal effects
• Animate masked areas for engaging UX
• Achieve complex designs with clean code

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🛠️ Masking a

with Another

To mask one div with another, we’ll create two elements:

1. A content div that holds the visible content.
2. A mask div that overlays and controls what part of the content is visible.

✅ HTML Structure:

⛶

class="content">
  This is the content you want to mask.
   class="mask">

✅ CSS:

⛶

.content {
  position: relative;
  z-index: 1;
}

.mask {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: black;
  opacity: 0.5;
  z-index: 2;
  pointer-events: none;
}

💡 Setting pointer-events: none ensures the mask doesn't block clicks on the content behind it.

🎨 Result:

The mask div will appear on top of the content with 50% opacity, giving a masked effect. Adjust the opacity for more or less visibility.

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🚀 Advanced CSS Masking Techniques

1. Using an Image as a Mask

Instead of a solid overlay, you can use an image as a mask:


⛶

.content {
  -webkit-mask-image: url('mask.png');
  -webkit-mask-size: cover;
  mask-image: url('mask.png');
  mask-size: cover;
}

This will apply the shape of the image to reveal or hide portions of the content.

🧠 Use images with transparent areas to define the visible sections of the masked element.

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2. Combining Multiple Masks

You can stack multiple masks to create layered effects:


⛶

.content {
  mask-image: url('mask1.png'), url('mask2.png');
  mask-composite: add;
  -webkit-mask-image: url('mask1.png'), url('mask2.png');
  -webkit-mask-composite: add;
}

Different mask-composite values like add, intersect, exclude, or subtract let you control how the masks interact.

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3. SVG Masks for Complex Shapes

SVG offers precise control over shapes and gradients. Here’s a simple SVG mask:


⛶

width="0" height="0">
   id="circle-mask">
     cx="50" cy="50" r="40" fill="white" />
  


 class="svg-mask">This is masked

⛶

.svg-mask {
  mask: url(#circle-mask);
  -webkit-mask: url(#circle-mask);
}

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🧪 Tips for Experimenting with CSS Masking

• Try different mask-size values: contain, cover, or exact dimensions
• Use mask-repeat and mask-position for control
• Combine with transform, hover, or animation for interactivity
• Use dev tools to preview mask layering and stacking

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✅ Conclusion

CSS masking opens up a world of creative possibilities in front-end design. Whether you're building slick UI transitions, interactive elements, or layered backgrounds, masking gives you fine-grained control without heavy resources.

Start simple by masking one div with another, and scale up using images, SVGs, and composites to push your designs to the next level.

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❓ FAQs

What is CSS masking?

CSS masking is the process of hiding parts of an element using another element or image as a mask.

Can I use a

to mask another

?

Yes, you can overlay a

with styles like background-color and opacity to create a mask effect.

Can I use an image as a mask in CSS?

Absolutely. Use the mask-image property to apply any transparent image as a mask.

How do I layer multiple masks?

Use mask-image with comma-separated URLs and control how they interact with mask-composite.

What’s the best use case for CSS masking?

CSS masking is perfect for visual effects, hover transitions, custom reveals, and non-rectangular UI components.

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