How does the width of Wechat's built-in browser reach 100%?

is working on a service number project, in which some web pages have backgrounds close to the bottom or side, but there will be some blank seams, as shown in figure

how to solve this problem?

Css
Oct.09,2021

* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
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-64f5-1eb1912-2367.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1eb1912-2367.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?