b) Accompany the object code with a copy of the GNU GPL and this license
   document.

  4. Combined Works.

  You may convey a Combined Work under terms of your choice that,
taken together, effectively do not restrict modification of the
portions of the Library contained in the Combined Work and reverse
engineering for debugging such modifications, if you also do each of
the following:

\"active\" buttons to the front to overlay\n    // the borders properly\n    @include hover() {\n      z-index: 1;\n    }\n    &:focus,\n    &:active,\n    &.active {\n      z-index: 1;\n    }\n  }\n}\n\n// Optional: Group multiple button groups together for a toolbar\n.btn-toolbar {\n  display: flex;\n  flex-wrap: wrap;\n  justify-content: flex-start;\n\n  .input-group {\n    width: auto;\n  }\n}\n\n.btn-group {\n  // Prevent double borders when buttons are next to each other\n  > .btn:not(:first-child),\n...