Understanding the 'box-sizing' Property in CSS

The 'box-sizing' property in CSS, as correctly identified in the quiz, dictates how the dimensions of a box are calculated. The 'box-sizing' property in CSS plays a huge part in layout design and significantly affects the approach designers use to create grid-like structures and manipulate the size and positioning of all elements on a page.

Box Sizing: Content-Box and Border-Box

The 'box-sizing' property can hold two values: 'content-box' and 'border-box'.

1. content-box: This is the default value for the 'box-sizing' attribute which allows designers to define a box model where the dimensions (width, height) of the box exclude padding and border thickness.

2. border-box: This allows a box model where the defined dimension of a box includes padding and border thickness in addition to the content. Thus, the box's size will remain constant, regardless of changes made to the padding or border thickness.

Here's a simple example to illustrate the two:

.div1 {
  box-sizing: content-box;
  width: 100px;
  padding: 20px;
  border: 5px solid black;
}

.div2 {
  box-sizing: border-box;
  width: 100px;
  padding: 20px;
  border: 5px solid black;
}

With 'content-box', .div1 will have a total width of 150px (100px width + 20px left padding + 20px right padding + 5px left border + 5px right border). However, with 'border-box', .div2 will maintain a width of 100px, since padding and border are included in the width.

Best Practices and Additional Insights

The ‘box-sizing’ property ultimately affects the visual layout and arrangement of elements on a webpage. Therefore, it's essential to consider the impact of the box-sizing value on the overall design during the development process.

In modern web design, using 'box-sizing: border-box' is a common practice, as it offers greater control over element dimensions and makes responsive design easier to implement. This is because it simplifies the calculations for width and height, especially when you're using percentage values or when the padding and border sizes vary.

In conclusion, the power of the 'box-sizing' property lies in understanding its use and the impact it has on the overall layout regime. Using 'box-sizing: border-box' simplifies layout designs and makes responsive web design easier and more fluid. Be sure to leverage this property to your advantage for an optimal web design experience!