fix GBK: GBK error in _tools.responsive.scss

error _tools.responsive.scss (Line 23, 31, 34, 48: Invalid GBK character
"\xE2")
Revert "fix GBK: GBK error in _tools.responsive.scss"

This reverts commit 0ce316476a93b9559d4cc4ec9c2aaa77e9c0c8aa.