Ionic 2 SplitPane changing sass variables not working

Hi I’m using split-pane component and want to change the min-width of the left panel according to my requirements .

For this I’m changing the the sass variables provided

but the change is not reflected in the main.css file after doing ionic serve .

First I thought it could be problem with sass but I changed another variable called @background-color and it worked .

Please can anyone help with this?