How to add a box shadow in CSS
To add box shadows, use the box-shadow attribute; 1. The basic syntax is box-shadow: horizontal offset vertical offset blur radius expansion radius shadows in color; 2. The first three values are required, and the rest are optional; 3. Use rgba() or hsla() to achieve transparent effect; 4. The positive expansion radius expands shadows and the negative value is reduced; 5. Multiple shadows can be added by commas separated; 6. Overuse should be avoided to ensure that visibility is tested on different backgrounds; this attribute is well supported by the browser, and reasonable use can improve the design texture.
To add a box shadow in CSS, use the box-shadow
property. It lets you apply one or more shadow effects to an element's frame. Here's how to use it effectively.

Basic Syntax
The box-shadow
property uses this format:
box-shadow: horizontal-offset vertical-offset blur-radius spread-radius color inset;
Only the first three values are required. The rest are optional and default to 0
if not specified.

Common Examples
Simple drop shadow :
.card { box-shadow: 2px 4px 8px rgba(0, 0, 0, 0.2); }
This creates a shadow 2px to the right, 4px down, with 8px blur and a slightly transparent black color.
Inset shadow (inside the element) :
.input-field { box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1); }
Useful for giving input fields a pressed or received look.
Multiple shadows : You can apply more than one shadow by separating them with commas:
.button { box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(255, 255, 255, 0.5); }
This adds a subtle drop shadow and a light inner border effect.
Key Tips
- Use
rgba()
orhsla()
colors for transparency instead of opaque black or white. - Larger
blur-radius
values create softer, more diffused shadows. - Positive
spread-radius
expands the shadow; negative values shrink it. - Always test shadows on different backgrounds to ensure visibility and contrast.
It's widely supported across browsers, so you can use it reliable. Just avoid overdoing it—subtle shadows often look more professional.
Basically, just pick your offset, tweak the blur, and choose a color that fits your design.
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