Use https when possible.

13 files changed, 17 insertions, 17 deletions

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 0aaa1bb949..e6a20558d0 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -178,7 +178,7 @@ included in the project:
    ```
 
 4. Commit your changes in logical chunks. Please adhere to these [git commit
-   message guidelines](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
+   message guidelines](https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
    or your code is unlikely be merged into the main project. Use Git's
    [interactive rebase](https://help.github.com/articles/about-git-rebase/)
    feature to tidy up your commits before making them public.
@@ -229,7 +229,7 @@ includes code changes) and under the terms of the
 [Adhere to the Code Guide.](http://codeguide.co/#css)
 
 - When feasible, default color palettes should comply with [WCAG color contrast guidelines](https://www.w3.org/TR/WCAG20/#visual-audio-contrast).
-- Except in rare cases, don't remove default `:focus` styles (via e.g. `outline: none;`) without providing alternative styles. See [this A11Y Project post](http://a11yproject.com/posts/never-remove-css-outlines/) for more details.
+- Except in rare cases, don't remove default `:focus` styles (via e.g. `outline: none;`) without providing alternative styles. See [this A11Y Project post](https://a11yproject.com/posts/never-remove-css-outlines/) for more details.
 
 ### JS
 
diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index 660428d8fd..9d9922f25f 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -40,7 +40,7 @@ Project maintainers who do not follow or enforce the Code of Conduct in good fai
 
 ## Attribution
 
-This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [http://contributor-covenant.org/version/1/4][version]
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [https://www.contributor-covenant.org/version/1/4/code-of-conduct.html][version]
 
-[homepage]: http://contributor-covenant.org
-[version]: http://contributor-covenant.org/version/1/4/
+[homepage]: https://www.contributor-covenant.org/
+[version]: https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
diff --git a/README.md b/README.md
index e12ed23ae4..9de9b357e2 100644
--- a/README.md
+++ b/README.md
@@ -148,7 +148,7 @@ Get updates on Bootstrap's development and chat with the project maintainers and
 
 ## Versioning
 
-For transparency into our release cycle and in striving to maintain backward compatibility, Bootstrap is maintained under [the Semantic Versioning guidelines](http://semver.org/). Sometimes we screw up, but we'll adhere to those rules whenever possible.
+For transparency into our release cycle and in striving to maintain backward compatibility, Bootstrap is maintained under [the Semantic Versioning guidelines](https://semver.org/). Sometimes we screw up, but we'll adhere to those rules whenever possible.
 
 See [the Releases section of our GitHub project](https://github.com/twbs/bootstrap/releases) for changelogs for each release version of Bootstrap. Release announcement posts on [the official Bootstrap blog](https://blog.getbootstrap.com/) contain summaries of the most noteworthy changes made in each release.
 
diff --git a/_data/translations.yml b/_data/translations.yml
index 44a1608d7c..38b5771c48 100644
--- a/_data/translations.yml
+++ b/_data/translations.yml
@@ -6,12 +6,12 @@
 - name: Chinese
   code: zh
   description: Bootstrap 4 · 全球最流行的 HTML、CSS 和 JS 工具库。
-  url: http://code.z01.com/v4
+  url: https://code.z01.com/v4
 
 - name: Chinese
   code: zh
   description: Bootstrap 4 中文文档教程
-  url: http://wiki.jikexueyuan.com/project/bootstrap4/
+  url: https://wiki.jikexueyuan.com/project/bootstrap4/
 
 - name: Brazilian Portuguese
   code: pt-BR
diff --git a/docs/4.0/extend/icons.md b/docs/4.0/extend/icons.md
index 761628f891..d32ee49d24 100644
--- a/docs/4.0/extend/icons.md
+++ b/docs/4.0/extend/icons.md
@@ -25,5 +25,5 @@ While we haven't tried these out, they do look promising and provide multiple fo
 - [Feather](https://feathericons.com/)
 - [Dripicons](http://demo.amitjakhu.com/dripicons/)
 - [Ikons](http://ikons.piotrkwiatkowski.co.uk/)
-- [Glyph](http://glyph.smarticons.co/)
+- [Glyph](https://glyph.smarticons.co/)
 - [Icons8](https://icons8.com/)
diff --git a/docs/4.0/getting-started/accessibility.md b/docs/4.0/getting-started/accessibility.md
index d4381aa21e..5a0c0b0ebe 100644
--- a/docs/4.0/getting-started/accessibility.md
+++ b/docs/4.0/getting-started/accessibility.md
@@ -50,7 +50,7 @@ Bootstrap includes support for the [`prefers-reduced-motion` media feature](http
 ## Additional resources
 
 - [Web Content Accessibility Guidelines (WCAG) 2.0](https://www.w3.org/TR/WCAG20/)
-- [The A11Y Project](http://a11yproject.com/)
+- [The A11Y Project](https://a11yproject.com/)
 - [MDN accessibility documentation](https://developer.mozilla.org/en-US/docs/Web/Accessibility)
 - [Tenon.io Accessibility Checker](https://tenon.io/)
 - [Colour Contrast Analyser (CCA)](https://developer.paciellogroup.com/resources/contrastanalyser/)
diff --git a/docs/4.0/getting-started/build-tools.md b/docs/4.0/getting-started/build-tools.md
index 3a569af24a..0185b374a4 100644
--- a/docs/4.0/getting-started/build-tools.md
+++ b/docs/4.0/getting-started/build-tools.md
@@ -28,7 +28,7 @@ Our [package.json]({{ site.repo }}/blob/v{{ site.current_version }}/package.json
 
 | Task | Description |
 | --- | --- |
-| `npm run dist` | `npm run dist` creates the `/dist` directory with compiled files. **Uses [Sass](http://sass-lang.com/), [Autoprefixer][autoprefixer], and [UglifyJS](https://github.com/mishoo/UglifyJS2).** |
+| `npm run dist` | `npm run dist` creates the `/dist` directory with compiled files. **Uses [Sass](https://sass-lang.com/), [Autoprefixer][autoprefixer], and [UglifyJS](https://github.com/mishoo/UglifyJS2).** |
 | `npm test` | Same as `npm run dist` plus it runs tests locally |
 | `npm run docs` | Builds and lints CSS and JavaScript for docs. You can then run the documentation locally via `npm run docs-serve`. |
 
diff --git a/docs/4.0/getting-started/download.md b/docs/4.0/getting-started/download.md
index 4e893e8c69..d9dbd5777b 100644
--- a/docs/4.0/getting-started/download.md
+++ b/docs/4.0/getting-started/download.md
@@ -60,7 +60,7 @@ npm install bootstrap
 
 Bootstrap's `package.json` contains some additional metadata under the following keys:
 
-- `sass` - path to Bootstrap's main [Sass](http://sass-lang.com/) source file
+- `sass` - path to Bootstrap's main [Sass](https://sass-lang.com/) source file
 - `style` - path to Bootstrap's non-minified CSS that's been precompiled using the default settings (no customization)
 
 ### RubyGems
diff --git a/docs/4.0/migration.md b/docs/4.0/migration.md
index f0cacc4c1d..b03250eadf 100644
--- a/docs/4.0/migration.md
+++ b/docs/4.0/migration.md
@@ -80,7 +80,7 @@ Here are the big ticket items you'll want to be aware of when moving from v3 to
 ### Global changes
 
 - **Flexbox is enabled by default.** In general this means a move away from floats and more across our components.
-- Switched from [Less](http://lesscss.org/) to [Sass](http://sass-lang.com/) for our source CSS files.
+- Switched from [Less](http://lesscss.org/) to [Sass](https://sass-lang.com/) for our source CSS files.
 - Switched from `px` to `rem` as our primary CSS unit, though pixels are still used for media queries and grid behavior as device viewports are not affected by type size.
 - Global font-size increased from `14px` to `16px`.
 - Revamped grid tiers to add a fifth option (addressing smaller devices at `576px` and below) and removed the `-xs` infix from those classes. Example: `.col-6.col-sm-4.col-md-3`.
diff --git a/js/tests/README.md b/js/tests/README.md
index 3f033e1dc4..1ba3d694e8 100644
--- a/js/tests/README.md
+++ b/js/tests/README.md
@@ -6,7 +6,7 @@ Bootstrap uses [QUnit](https://qunitjs.com/) and [Sinon](http://sinonjs.org/). E
 * `vendor/` contains third-party testing-related code (QUnit, jQuery and Sinon).
 * `visual/` contains "visual" tests which are run interactively in real browsers and require manual verification by humans.
 
-To run the unit test suite via [Karma](http://karma-runner.github.io/), run `npm run js-test`.
+To run the unit test suite via [Karma](https://karma-runner.github.io/), run `npm run js-test`.
 
 To run the unit test suite via a real web browser, open `index.html` in the browser.
 
diff --git a/scss/_custom-forms.scss b/scss/_custom-forms.scss
index 2d65dcbc92..54fa8751ce 100644
--- a/scss/_custom-forms.scss
+++ b/scss/_custom-forms.scss
@@ -157,7 +157,7 @@
 // Select
 //
 // Replaces the browser default select with a custom one, mostly pulled from
-// http://primercss.io.
+// https://primer.github.io/.
 //
 
 .custom-select {
diff --git a/scss/_print.scss b/scss/_print.scss
index 98163eb10a..0c13de2781 100644
--- a/scss/_print.scss
+++ b/scss/_print.scss
@@ -5,7 +5,7 @@
 // ==========================================================================
 // Print styles.
 // Inlined to avoid the additional HTTP request:
-// http://www.phpied.com/delay-loading-your-print-css/
+// https://www.phpied.com/delay-loading-your-print-css/
 // ==========================================================================
 
 @if $enable-print-styles {
diff --git a/scss/mixins/_screen-reader.scss b/scss/mixins/_screen-reader.scss
index f9cd35cffe..812591bc5e 100644
--- a/scss/mixins/_screen-reader.scss
+++ b/scss/mixins/_screen-reader.scss
@@ -1,6 +1,6 @@
 // Only display content to screen readers
 //
-// See: http://a11yproject.com/posts/how-to-hide-content/
+// See: https://a11yproject.com/posts/how-to-hide-content/
 // See: https://hugogiraudel.com/2016/10/13/css-hide-and-seek/
 
 @mixin sr-only {