How the SVG icon dynamically modifies the icon color

how the SVG icon dynamically modifies the icon color, or how to change the icon color when hover

< H1 > functionButtonGroup svg:hover {< / H1 >
fill:red 

}
I wrote such a code, but it didn"t work

Mar.11,2021
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-64f5-1e5ab06-455db.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e5ab06-455db.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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