To reproduce:

https://lesscss.org/less-preview/#eyJjb2RlIjoiQGNvbnRhaW5lciBzdHlsZSgtLXRoZW1lOiBkYXJrKXtcbiAgLm1haW57XG4gICAgY29sb3I6IzAwMDtcbiAgfVxufVxuXG4iLCJhY3RpdmVWZXJzaW9uIjoiNC4yLjAiLCJtYXRoIjoicGFyZW5zLWRpdmlzaW9uIiwic3RyaWN0VW5pdHMiOmZhbHNlfQ==

@container style(--theme: dark){
  .main{
    color: #000;
  }
}

Current behavior:
There's a space between "style" and the bracket.

@container style (--theme: dark)

Expected behavior:
No space between "style" and the bracket.

@container style(--theme: dark)

Environment information:

• less version: 4.2.0