css: Use SCSS nesting for `.landing-page` in portico.scss.
css: Use SCSS nesting for `.landing-page` in portico.scss.

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