A question of BFC

BFC has a feature: child elements in the BFC container do not affect the outer elements, and vice versa;

however, as shown in the following picture, the blue box floats to the left and the orange box does not float. The blue box affects the orange box, covers the orange box, and makes the contents of the orange box move 100px to the right. It does not match the description of the above characteristics. Why? do I understand it wrong?

Code:

<style>
  body {
    width: 300px;
  }
  .aside {
    width: 100px;
    height: 150px;
    float: left;
    background: blue;
  }
  .main {
    height: 200px;
    background: orange;
  }
</style>
<body>
  <div class="aside"></div>
  <div class="main"></div>
</body>
Css
Mar.12,2021
The child elements in the

BFC container do not affect the elements outside this container .

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-64f5-1b33305-2be81.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b33305-2be81.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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