CSS gradients are rendered natively by the browser engine, which means they are resolution-independent and require zero HTTP requests -- unlike image-based backgrounds that must be downloaded. The linear-gradient() function creates a color transition along a straight line defined by an angle (e.g., 135deg) or direction keyword (e.g., to bottom right). The radial-gradient() function radiates colors outward from a center point in an elliptical or circular shape. The newer conic-gradient() sweeps colors around a center point like a color wheel. Each function accepts color stops that define which colors appear at which positions along the gradient line.

A common problem with gradients is visible banding -- the appearance of discrete color steps instead of a smooth transition. This typically occurs when transitioning between colors that are far apart in hue or when the gradient covers a large area. The fix is to add intermediate color stops at midpoints between your start and end colors. For example, when blending from deep blue to bright orange, inserting a purple or mauve midpoint creates a perceptually smoother transition. Some designers also add a subtle noise overlay to further mask banding artifacts, though this requires an additional CSS layer.

From a performance perspective, CSS gradients are composited on the GPU and are significantly cheaper than equivalent image backgrounds. They do not trigger layout recalculations and are repainted efficiently. However, extremely complex gradients with many color stops or animations that change gradient values on every frame can cause paint-heavy operations. For animated effects, consider using CSS custom properties to transition specific stop positions rather than rewriting the entire gradient declaration. This lets the browser optimize the repaint region.

Practical gradient patterns include image overlays (a semi-transparent gradient over a background image to improve text readability), text backgrounds using background-clip: text, frosted glass effects combining gradients with backdrop-filter, and decorative accent strips. When designing gradients for production, always test on multiple screen types -- gradients that look smooth on a high-DPI retina display may exhibit banding on lower-quality panels. This tool lets you experiment with all these parameters in real time and copy the resulting CSS directly into your stylesheet.