2 directories seem to use a different HTML template:
No CSS, non empty:
http://www.avidemux.org/nightly/osx_snow_leopard_qt4/ (http://www.avidemux.org/nightly/osx_snow_leopard_qt4/)
No CSS, empty:
http://www.avidemux.org/nightly/win32_ffmpeg31/ (http://www.avidemux.org/nightly/win32_ffmpeg31/)
(CSS, empty):
http://www.avidemux.org/nightly/win32_debug/ (http://www.avidemux.org/nightly/win32_debug/)
http://www.avidemux.org/nightly/win64_debug/ (http://www.avidemux.org/nightly/win64_debug/)