Unable to save custom theme CSS 12.0.8

Worked in Version 12.0.4

But when i tried to copy paste the theme css code to 12.0.8 , unable to save it . gets below error

/home/frappe/frappe-bench/apps/frappe/generate_bootstrap_theme.js:26
...get_options_for_scss()
^^^

SyntaxError: Unexpected token ...
at createScript (vm.js:56:10)
at Object.runInThisContext (vm.js:97:10)
at Module._compile (module.js:542:28)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
at Module.runMain (module.js:604:10)
at run (bootstrap_node.js:389:7)
at startup (bootstrap_node.js:149:9)