css: Use SCSS nesting in app_components.scss for `.overlay`.
css: Use SCSS nesting in app_components.scss for `.overlay`.

andersk/zulip,tommyip/zulip,kou/zulip,brainwane/zulip,brainwane/zulip,hackerkid/zulip,shubhamdhama/zulip,andersk/zulip,punchagan/zulip,shubhamdhama/zulip,andersk/zulip,brainwane/zulip,punchagan/zulip,rishig/zulip,tommyip/zulip,kou/zulip,brainwane/zulip,synicalsyntax/zulip,punchagan/zulip,andersk/zulip,synicalsyntax/zulip,shubhamdhama/zulip,hackerkid/zulip,rht/zulip,showell/zulip,hackerkid/zulip,zulip/zulip,eeshangarg/zulip,andersk/zulip,rht/zulip,rishig/zulip,synicalsyntax/zulip,kou/zulip,kou/zulip,shubhamdhama/zulip,rht/zulip,shubhamdhama/zulip,rht/zulip,eeshangarg/zulip,rishig/zulip,rht/zulip,rht/zulip,punchagan/zulip,eeshangarg/zulip,timabbott/zulip,punchagan/zulip,punchagan/zulip,eeshangarg/zulip,synicalsyntax/zulip,zulip/zulip,hackerkid/zulip,timabbott/zulip,eeshangarg/zulip,showell/zulip,andersk/zulip,shubhamdhama/zulip,rishig/zulip,timabbott/zulip,tommyip/zulip,timabbott/zulip,tommyip/zulip,synicalsyntax/zulip,timabbott/zulip,synicalsyntax/zulip,eeshangarg/zulip,timabbott/zulip,zulip/zulip,zulip/zulip,showell/zulip,kou/zulip,zulip/zulip,showell/zulip,showell/zulip,punchagan/zulip,brainwane/zulip,kou/zulip,tommyip/zulip,zulip/zulip,rishig/zulip,tommyip/zulip,shubhamdhama/zulip,timabbott/zulip,synicalsyntax/zulip,andersk/zulip,eeshangarg/zulip,brainwane/zulip,hackerkid/zulip,tommyip/zulip,showell/zulip,rishig/zulip,hackerkid/zulip,kou/zulip,zulip/zulip,hackerkid/zulip,rht/zulip,rishig/zulip,brainwane/zulip,showell/zulip