Flat UI - http://designmodo.github.io/Flat-UI/
LibreNMS is an autodiscovering PHP/MySQL/SNMP based network monitoring which includes support for a wide range of network hardware and operating systems including Cisco, Linux, FreeBSD, Juniper, Brocade, Foundry, HP and many more.
Documentation can be found in the https://github.com/librenms/librenms/tree/master/doc/ or http://docs.librenms.org/, including instructions for installing and contributing.