Extend part .less file

Question

I'm new to magento and couldn't find an answer for the following question: Is it posible to extend only a part/property of the parent .less file?

So when the original for example looks like:

    ...more 'less'
    .media-width(@extremum, @break) when (@extremum = 'min') and (@break = @screen__m) {
        .block-search {
            float: right;
            padding-left: 15px;
            position: relative;
            width: 250px;
            z-index: 4;

            .label {
                &:extend(.abs-visually-hidden-desktop all);
            }
}
     ...more 'less'

And I only want to change the float:right; to float:left; it doesn't seems to work to create the same file (and structure) in my own theme (that has this parent set) and in that less file only set:

.media-width(@extremum, @break) when (@extremum = 'min') and (@break = @screen__m) {
    .block-search {
        float: left;
}
}

Answer 1

Try putting your code in theme_dir/web/css/source/_extend.less instead.