portico: Add hover behaviour to `Take the tour` button on /hello.
portico: Add hover behaviour to `Take the tour` button on /hello.

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