I improved the modal's functionality by dividing it into two distinct sections: one for counting guests and the other dedicated to cost calculation. This separation was aimed at simplifying the user interface, making it more intuitive.
All types of costs were grouped together to create a calculator-like experience, with main sums displayed at the bottom.
I introduced a clear distinction in the presentation of costs – fixed sums were placed under the 'fixed' label and sums divided per guest under the 'per guest' label. The selector changes the input states (from active to disabled) to reduce user confusion, while ensuring all information is visible by default.
Additionally, I separated the costs added before the event from the final ones to provide a clearer financial overview.