calc() is a unique CSS function that allows for simple math calculations within stylesheets.
rem represents the Root EM unit, which is based on the root font-size
. Typically, most browsers have a default font size of 16px. Therefore, 1.25rem would be equivalent to 20px (1.25 x 16px).
vw refers to view width and is a percentage relative to the browser window's width. For example, if a browser is in full screen mode on a 1920x1080px monitor, the viewport width would be 1920px, resulting in 5.76px at 0.003 of the total width.
When combining the calc function with these units, the resulting width would be 25.76px (20px + 5.76px). Keep in mind that these values are responsive and may vary on different screens and font sizes.