new-templane/resources/sass/base/_fonts.scss

@mixin font-face($font-family, $file-path, $weight: normal, $style: normal) {
  @font-face {
    font-family: $font-family;
    font-weight: $weight;
    font-style: $style;
    font-display: swap;

    // Порядок: сначала woff2, потом woff, потом ttf
    src: url('#{$file-path}.woff2') format('woff2'),
         //url('#{$file-path}.woff')  format('woff'),
         //url('#{$file-path}.ttf')   format('truetype');
  }
}

@include font-face("Montserrat", "../fonts/Montserrat-Regular", 400);
@include font-face("Montserrat", "../fonts/Montserrat-SemiBold", 600);
@include font-face("Montserrat", "../fonts/Montserrat-Bold", 700);