Hello Marcos -
UPDATE, IT WORKS : When I dug up the page source for one of the broken pages (the installer yielded a broken install again) and manually accessed the CSS files (I could), I had to make a "security exception" because of the expired certificate on my webserver.
Once I did this, it worked.
1) Here's the contents of INSTALLDIR/apache2/logs/error_log
[Mon Dec 28 10:45:55.531242 2015] [ssl:warn] [pid 7593] AH01909: localhost:8443:0 server certificate does NOT include an ID which matches the server name
[Mon Dec 28 10:45:55.625581 2015] [ssl:warn] [pid 7604] AH01909: localhost:8443:0 server certificate does NOT include an ID which matches the server name
[Mon Dec 28 10:45:55.625863 2015] [lbmethod_heartbeat:notice] [pid 7604] AH02282: No slotmem from mod_heartmonitor
[Mon Dec 28 10:45:55.669840 2015] [mpm_prefork:notice] [pid 7604] AH00163: Apache/2.4.17 (Unix) OpenSSL/1.0.1q PHP/5.5.30 configured -- resuming normal operations
[Mon Dec 28 10:45:55.669914 2015] [core:notice] [pid 7604] AH00094: Command line: '/home/apourati/servers/phabricator/apache2/bin/httpd.bin -f /home/apourati/servers/phabricator/apache2/conf/httpd.conf'
[Mon Dec 28 10:46:03.118690 2015] [mpm_prefork:notice] [pid 7604] AH00169: caught SIGTERM, shutting down
[Mon Dec 28 10:46:05.935794 2015] [ssl:warn] [pid 8265] AH01909: localhost:8443:0 server certificate does NOT include an ID which matches the server name
[Mon Dec 28 10:46:06.028819 2015] [ssl:warn] [pid 8275] AH01909: localhost:8443:0 server certificate does NOT include an ID which matches the server name
[Mon Dec 28 10:46:06.029135 2015] [lbmethod_heartbeat:notice] [pid 8275] AH02282: No slotmem from mod_heartmonitor
[Mon Dec 28 10:46:06.075179 2015] [mpm_prefork:notice] [pid 8275] AH00163: Apache/2.4.17 (Unix) OpenSSL/1.0.1q PHP/5.5.30 configured -- resuming normal operations
[Mon Dec 28 10:46:06.075244 2015] [core:notice] [pid 8275] AH00094: Command line: '/home/apourati/servers/phabricator/apache2/bin/httpd.bin -f /home/apourati/servers/phabricator/apache2/conf/httpd.conf'
[Mon Dec 28 10:46:37.494805 2015] [mpm_prefork:notice] [pid 8275] AH00169: caught SIGTERM, shutting down
[Mon Dec 28 10:46:40.247911 2015] [ssl:warn] [pid 10343] AH01909: localhost:8443:0 server certificate does NOT include an ID which matches the server name
[Mon Dec 28 10:46:40.337990 2015] [ssl:warn] [pid 10352] AH01909: localhost:8443:0 server certificate does NOT include an ID which matches the server name
[Mon Dec 28 10:46:40.338291 2015] [lbmethod_heartbeat:notice] [pid 10352] AH02282: No slotmem from mod_heartmonitor
[Mon Dec 28 10:46:40.384330 2015] [mpm_prefork:notice] [pid 10352] AH00163: Apache/2.4.17 (Unix) OpenSSL/1.0.1q PHP/5.5.30 configured -- resuming normal operations
[Mon Dec 28 10:46:40.384391 2015] [core:notice] [pid 10352] AH00094: Command line: '/home/apourati/servers/phabricator/apache2/bin/httpd.bin -f /home/apourati/servers/phabricator/apache2/conf/httpd.conf'
Thank you for your time,