Fixed width columns

Getting tired of using ratios to define st.columns since it all falls apart as soon as the user resizes their screen. Anyone had luck creating fixed + variable width columns in Streamlit? For example, a list of [100, 0.8, 0.2] would create 3 columns, first with a fixed width of 100px, 2nd fills 80% of the remaining space and the 3rd fills the final 20%.

Been trying to implement this using just st.columns + CSS but it is impossible to target the correct set of columns on the page (if streamlit added a class arg to all components that would massively simplify so much with custom CSS…).