hidden class added by Modernizr causes blank page when combined with bootstrap

[tschallacka]

Relevant: Modernizr/Modernizr#2147

Reproduce:
make html page with bootstrap
add Modernizr.js compiled with the following modernizr-config.json

{
  "minify": true,
  "options": [
    "setClasses"
  ],
  "feature-detects": [
    "test/dom/hidden",
  ]
}

suggested solution:

make

bootstrap/scss/mixins/_visibility.scss

Line 4 in 96d8553

visibility: hidden !important;

html .hidden instead of just .hidden

[ryanseddon]

For reference: Modernizr/Modernizr#2147 (comment)

[mdo]

This won't be a problem anymore with #22113.