After updating to Magento 2.1.16 on my staging server with nginx server and php7.0 I am facing issue in compiling less and css files.
styles-m.css are missing - not generated.
During static contend deploy I get errors:
Compilation from source: /srv/www/rmstaging/public_html/vendor/magento/theme-frontend-blank/web/css/styles-l.less
Compilation from source: frontend/Smartwave/porto_rtl/en_US/css/styles-l.less variable @modal-popup-breakpoint-screen__m is undefined in file /srv/www/rmstaging/public_html/var/view_preprocessed/css/frontend/Smartwave/porto_rtl/en_US/Magento_Checkout/css/source/module/checkout/_tooltip.less in _tooltip.less on line 11, column 41
I tried many solution including on given in https://stackoverflow.com/questions/50764127/magento-2-less-compilation-error-while-setupstatic-contentdeploy-and-frontend given by @Ashsih Raj. But did not work either.
I had the same issue on localhost but that was fixed mysteriously. I think the only change is that on my localhost I compiles using PHP7.1