CSS percentage minus pixels
CSS Percentages Minus Pixels
In CSS, we can use percentages and pixels to set the size and position of elements. Percentages are relative to the size of the parent element, while pixels are a fixed unit. In some cases, we may need to subtract pixels from percentages, which is particularly useful when designing responsive web layouts.
Why Subtract Pixels from Percentages
In web design, we often encounter situations where we need to resize elements based on the page width. Percentages are a good choice for these situations, as they automatically adjust to the size of the parent element. However, sometimes we want to slightly reduce the size of an element. In this case, we can achieve this by subtracting pixels from the percentage.
How to Subtract Pixels from Percentages in CSS
In CSS, we can use calculation functions to subtract pixels from percentages. CSS3 introduced the calc() function, which allows us to perform mathematical operations on CSS properties. By combining percentages with pixels and the calc() function, we can subtract pixels from percentages.
.element {
width: calc(50% - 10px);
}
In the example above, we set the width of an element to 50% of its parent’s width and then subtracted 10 pixels. This effectively subtracts pixels from a percentage.
Example Code
Let’s use a simple example to demonstrate how to subtract pixels from a percentage in CSS.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Percentage Minus Pixels</title>
<style>
.container {
width: 80%;
margin: 0 auto;
background-color: lightgray;
padding: 20px;
}
.box {
width: calc(50% - 20px);
height: 100px;
background-color: skyblue;
margin-top: 10px;
}
</style>
</head>
<body>
<div class="container">
<div class="box"></div>
</div>
</body>
</html>
In the example above, we create a container element .container that is 80% of the page width and is centered. Then, within this container, a blue box .box is created with a width equal to 50% of the parent element’s width minus 20 pixels. This effectively subtracts pixels from a percentage.
Running the example code in a browser, you’ll see that the container’s width is 80% of the page width and contains a blue box with a width equal to 50% minus 20 pixels. This effectively subtracts pixels from a percentage.
By mastering the use of calculation functions in CSS to subtract pixels from percentages, we can design responsive web layouts with greater flexibility, ensuring that pages display well across different devices.