Boostrp latest source code, can study.

bootstrap-3.3.5
...............\.editorconfig
...............\.gitattributes
...............\.gitignore
...............\.travis.yml
...............\CNAME
...............\CONTRIBUTING.md
...............\Gruntfile.js
...............\LICENSE
...............\README.md
...............\_config.yml
...............\bower.json
...............\composer.json
...............\dist
...............\....\css
...............\....\...\bootstrap-theme.css
...............\....\...\bootstrap-theme.css.map
...............\....\...\bootstrap-theme.min.css
...............\....\...\bootstrap.css
...............\....\...\bootstrap.css.map
...............\....\...\bootstrap.min.css
...............\....\fonts
...............\....\.....\glyphicons-halflings-regular.eot
...............\....\.....\glyphicons-halflings-regular.svg
...............\....\.....\glyphicons-halflings-regular.ttf
...............\....\.....\glyphicons-halflings-regular.woff
...............\....\.....\glyphicons-halflings-regular.woff2
...............\....\js
...............\....\..\bootstrap.js
...............\....\..\bootstrap.min.js
...............\....\..\npm.js
...............\docs
...............\....\LICENSE
...............\....\_data
...............\....\.....\browser-bugs.yml
...............\....\.....\core-team.yml
...............\....\.....\glyphicons.yml
...............\....\.....\sass-team.yml
...............\....\.....\showcase.yml
...............\....\.....\translations.yml
...............\....\_includes
...............\....\.........\ads.html
...............\....\.........\components
...............\....\.........\..........\alerts.html
...............\....\.........\..........\badges.html
...............\....\.........\..........\breadcrumbs.html
...............\....\.........\..........\button-dropdowns.html
...............\....\.........\..........\button-groups.html
...............\....\.........\..........\dropdowns.html
...............\....\.........\..........\glyphicons.html
...............\....\.........\..........\input-groups.html
...............\....\.........\..........\jumbotron.html
...............\....\.........\..........\labels.html
...............\....\.........\..........\list-group.html
...............\....\.........\..........\media.html
...............\....\.........\..........\navbar.html
...............\....\.........\..........\navs.html
...............\....\.........\..........\page-header.html
...............\....\.........\..........\pagination.html
...............\....\.........\..........\panels.html
...............\....\.........\..........\progress-bars.html
...............\....\.........\..........\responsive-embed.html
...............\....\.........\..........\thumbnails.html
...............\....\.........\..........\wells.html
...............\....\.........\css
...............\....\.........\...\buttons.html
...............\....\.........\...\code.html
...............\....\.........\...\forms.html
...............\....\.........\...\grid.html
...............\....\.........\...\helpers.html
...............\....\.........\...\images.html
...............\....\.........\...\less.html
...............\....\.........\...\overview.html
...............\....\.........\...\responsive-utilities.html
...............\....\.........\...\sass.html
...............\....\.........\...\tables.html
...............\....\.........\...\type.html
...............\....\.........\customizer-variables.html
...............\....\.........\footer.html
...............\....\.........\getting-started
...............\....\.........\...............\accessibility.html
...............\....\.........\...............\browser-device-support.html
...............\....\.........\...............\community.html
...............\....\.........\...............\disabling-responsiveness.html
...............\....\.........\...............\download.html
...............\....\.........\...............\examples.html
...............\....\.........\...............\grunt.html
...............\....\.........\...............\license.html
...............\....\.........\...............\t

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