"Log files do not contain pages; they contain a series of log records."
now what is this 'series of log records'? are they not saved in any files/pages?
No. The disc has a number of blocks that, combined, contain the log file. The log file contains log records. The disc also has a whole load more blocks that, combined, contain the data file, and that data file contains its data stored in SQL Server-allocated logical chunks called pages.
A log file doesn't contain pages any more than a text file does. Of course, if that text file or log file is opened up into memory, a number of memory pages will be allocated to hold the data that makes up the file. However, even then, it's the OS pages that hold the file, not the other way round.
Semper in excretia, sumus solum profundum variat