How does ionic4 develop APP, to adapt different mobile phones?

recently I just learned that the ionic4, page is written normally: px. There is a question, how to deal with the adaptation of different mobile phones? Before I wrote H5, I used rem.

Feb.24,2022

consulted, and the preliminary understanding is that the conversion from px to rem, is similar to that when writing H5

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1ea0074-1aa5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1ea0074-1aa5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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