using bootstrap classes in style.less

hello
first i want to say thank's for you'r good job

i have a question about mixins
i want to use classes like well,panel,... in style.less but it dosen't work,or i want to use img-thumbnail in style.less

this is a sample

in templates\t3_bs3_blank\less\style.less

.t3-content .blog .item
{
.well();
}