There are many ways to convert pixels to rem units, but this is the simplest and most accurate method:

// Define a function called 'toRem' to convert pixels to rem units
@function toRem($value) {

  // Divide the pixel value by 16 to get the rem value and multiply by 1rem to set the unit
  $remValue: ($value / 16) * 1rem;
  
  // Return the calculated rem value
  @return $remValue;
}

The accuracy of this method lies in using a mathematical operation to convert a px value to rem. Here, the $value is divided by 16 to convert it into rem units. By multiplying with 1rem, SCSS automatically applies the correct unit conversion, ensuring proper scaling."

This approach is both simple and accurate, making it ideal for responsive design foundations.