diff --git a/src/components/markdown-renderer/slideshow.scss b/src/components/markdown-renderer/slideshow.scss
index 1e8dadfe0..c8a98232c 100644
--- a/src/components/markdown-renderer/slideshow.scss
+++ b/src/components/markdown-renderer/slideshow.scss
@@ -7,8 +7,3 @@
 @import "../../../node_modules/reveal.js/css/reveal";
 @import "../../../node_modules/reveal.js/dist/theme/fonts/league-gothic/league-gothic.css";
 @import "slide-theme";
-
-//Fix to make transitions work with bootstrap
-.reveal [hidden] {
-  display: block !important;
-}
diff --git a/src/style/bootstrap-vendor/_reboot.scss b/src/style/bootstrap-vendor/_reboot.scss
new file mode 100644
index 000000000..2cf1b8fb5
--- /dev/null
+++ b/src/style/bootstrap-vendor/_reboot.scss
@@ -0,0 +1,486 @@
+/*!
+ * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+// stylelint-disable declaration-no-important, selector-no-qualifying-type, property-no-vendor-prefix
+
+// Reboot
+//
+// Normalization of HTML elements, manually forked from Normalize.css to remove
+// styles targeting irrelevant browsers while applying new styles.
+//
+// Normalize is licensed MIT. https://github.com/necolas/normalize.css
+
+
+// Document
+//
+// 1. Change from `box-sizing: content-box` so that `width` is not affected by `padding` or `border`.
+// 2. Change the default font family in all browsers.
+// 3. Correct the line height in all browsers.
+// 4. Prevent adjustments of font size after orientation changes in IE on Windows Phone and in iOS.
+// 5. Change the default tap highlight to be completely transparent in iOS.
+
+*,
+*::before,
+*::after {
+  box-sizing: border-box; // 1
+}
+
+html {
+  font-family: sans-serif; // 2
+  line-height: 1.15; // 3
+  -webkit-text-size-adjust: 100%; // 4
+  -webkit-tap-highlight-color: rgba($black, 0); // 5
+}
+
+// Shim for "new" HTML5 structural elements to display correctly (IE10, older browsers)
+// TODO: remove in v5
+// stylelint-disable-next-line selector-list-comma-newline-after
+article, aside, figcaption, figure, footer, header, hgroup, main, nav, section {
+  display: block;
+}
+
+// Body
+//
+// 1. Remove the margin in all browsers.
+// 2. As a best practice, apply a default `background-color`.
+// 3. Set an explicit initial text-align value so that we can later use
+//    the `inherit` value on things like `<th>` elements.
+
+body {
+  margin: 0; // 1
+  font-family: $font-family-base;
+  @include font-size($font-size-base);
+  font-weight: $font-weight-base;
+  line-height: $line-height-base;
+  color: $body-color;
+  text-align: left; // 3
+  background-color: $body-bg; // 2
+}
+
+// Future-proof rule: in browsers that support :focus-visible, suppress the focus outline
+// on elements that programmatically receive focus but wouldn't normally show a visible
+// focus outline. In general, this would mean that the outline is only applied if the
+// interaction that led to the element receiving programmatic focus was a keyboard interaction,
+// or the browser has somehow determined that the user is primarily a keyboard user and/or
+// wants focus outlines to always be presented.
+//
+// See https://developer.mozilla.org/en-US/docs/Web/CSS/:focus-visible
+// and https://developer.paciellogroup.com/blog/2018/03/focus-visible-and-backwards-compatibility/
+[tabindex="-1"]:focus:not(:focus-visible) {
+  outline: 0 !important;
+}
+
+
+// Content grouping
+//
+// 1. Add the correct box sizing in Firefox.
+// 2. Show the overflow in Edge and IE.
+
+hr {
+  box-sizing: content-box; // 1
+  height: 0; // 1
+  overflow: visible; // 2
+}
+
+
+//
+// Typography
+//
+
+// Remove top margins from headings
+//
+// By default, `<h1>`-`<h6>` all receive top and bottom margins. We nuke the top
+// margin for easier control within type scales as it avoids margin collapsing.
+// stylelint-disable-next-line selector-list-comma-newline-after
+h1, h2, h3, h4, h5, h6 {
+  margin-top: 0;
+  margin-bottom: $headings-margin-bottom;
+}
+
+// Reset margins on paragraphs
+//
+// Similarly, the top margin on `<p>`s get reset. However, we also reset the
+// bottom margin to use `rem` units instead of `em`.
+p {
+  margin-top: 0;
+  margin-bottom: $paragraph-margin-bottom;
+}
+
+// Abbreviations
+//
+// 1. Duplicate behavior to the data-* attribute for our tooltip plugin
+// 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
+// 3. Add explicit cursor to indicate changed behavior.
+// 4. Remove the bottom border in Firefox 39-.
+// 5. Prevent the text-decoration to be skipped.
+
+abbr[title],
+abbr[data-original-title] { // 1
+  text-decoration: underline; // 2
+  text-decoration: underline dotted; // 2
+  cursor: help; // 3
+  border-bottom: 0; // 4
+  text-decoration-skip-ink: none; // 5
+}
+
+address {
+  margin-bottom: 1rem;
+  font-style: normal;
+  line-height: inherit;
+}
+
+ol,
+ul,
+dl {
+  margin-top: 0;
+  margin-bottom: 1rem;
+}
+
+ol ol,
+ul ul,
+ol ul,
+ul ol {
+  margin-bottom: 0;
+}
+
+dt {
+  font-weight: $dt-font-weight;
+}
+
+dd {
+  margin-bottom: .5rem;
+  margin-left: 0; // Undo browser default
+}
+
+blockquote {
+  margin: 0 0 1rem;
+}
+
+b,
+strong {
+  font-weight: $font-weight-bolder; // Add the correct font weight in Chrome, Edge, and Safari
+}
+
+small {
+  @include font-size(80%); // Add the correct font size in all browsers
+}
+
+//
+// Prevent `sub` and `sup` elements from affecting the line height in
+// all browsers.
+//
+
+sub,
+sup {
+  position: relative;
+  @include font-size(75%);
+  line-height: 0;
+  vertical-align: baseline;
+}
+
+sub { bottom: -.25em; }
+sup { top: -.5em; }
+
+
+//
+// Links
+//
+
+a {
+  color: $link-color;
+  text-decoration: $link-decoration;
+  background-color: transparent; // Remove the gray background on active links in IE 10.
+
+  @include hover() {
+    color: $link-hover-color;
+    text-decoration: $link-hover-decoration;
+  }
+}
+
+// And undo these styles for placeholder links/named anchors (without href).
+// It would be more straightforward to just use a[href] in previous block, but that
+// causes specificity issues in many other styles that are too complex to fix.
+// See https://github.com/twbs/bootstrap/issues/19402
+
+a:not([href]):not([class]) {
+  color: inherit;
+  text-decoration: none;
+
+  @include hover() {
+    color: inherit;
+    text-decoration: none;
+  }
+}
+
+
+//
+// Code
+//
+
+pre,
+code,
+kbd,
+samp {
+  font-family: $font-family-monospace;
+  @include font-size(1em); // Correct the odd `em` font sizing in all browsers.
+}
+
+pre {
+  // Remove browser default top margin
+  margin-top: 0;
+  // Reset browser default of `1em` to use `rem`s
+  margin-bottom: 1rem;
+  // Don't allow content to break outside
+  overflow: auto;
+  // Disable auto-hiding scrollbar in IE & legacy Edge to avoid overlap,
+  // making it impossible to interact with the content
+  -ms-overflow-style: scrollbar;
+}
+
+
+//
+// Figures
+//
+
+figure {
+  // Apply a consistent margin strategy (matches our type styles).
+  margin: 0 0 1rem;
+}
+
+
+//
+// Images and content
+//
+
+img {
+  vertical-align: middle;
+  border-style: none; // Remove the border on images inside links in IE 10-.
+}
+
+svg {
+  // Workaround for the SVG overflow bug in IE10/11 is still required.
+  // See https://github.com/twbs/bootstrap/issues/26878
+  overflow: hidden;
+  vertical-align: middle;
+}
+
+
+//
+// Tables
+//
+
+table {
+  border-collapse: collapse; // Prevent double borders
+}
+
+caption {
+  padding-top: $table-cell-padding;
+  padding-bottom: $table-cell-padding;
+  color: $table-caption-color;
+  text-align: left;
+  caption-side: bottom;
+}
+
+// 1. Removes font-weight bold by inheriting
+// 2. Matches default `<td>` alignment by inheriting `text-align`.
+// 3. Fix alignment for Safari
+
+th {
+  font-weight: $table-th-font-weight; // 1
+  text-align: inherit; // 2
+  text-align: -webkit-match-parent; // 3
+}
+
+
+//
+// Forms
+//
+
+label {
+  // Allow labels to use `margin` for spacing.
+  display: inline-block;
+  margin-bottom: $label-margin-bottom;
+}
+
+// Remove the default `border-radius` that macOS Chrome adds.
+//
+// Details at https://github.com/twbs/bootstrap/issues/24093
+button {
+  // stylelint-disable-next-line property-disallowed-list
+  border-radius: 0;
+}
+
+// Explicitly remove focus outline in Chromium when it shouldn't be
+// visible (e.g. as result of mouse click or touch tap). It already
+// should be doing this automatically, but seems to currently be
+// confused and applies its very visible two-tone outline anyway.
+
+button:focus:not(:focus-visible) {
+  outline: 0;
+}
+
+input,
+button,
+select,
+optgroup,
+textarea {
+  margin: 0; // Remove the margin in Firefox and Safari
+  font-family: inherit;
+  @include font-size(inherit);
+  line-height: inherit;
+}
+
+button,
+input {
+  overflow: visible; // Show the overflow in Edge
+}
+
+button,
+select {
+  text-transform: none; // Remove the inheritance of text transform in Firefox
+}
+
+// Set the cursor for non-`<button>` buttons
+//
+// Details at https://github.com/twbs/bootstrap/pull/30562
+[role="button"] {
+  cursor: pointer;
+}
+
+// Remove the inheritance of word-wrap in Safari.
+//
+// Details at https://github.com/twbs/bootstrap/issues/24990
+select {
+  word-wrap: normal;
+}
+
+
+// 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
+//    controls in Android 4.
+// 2. Correct the inability to style clickable types in iOS and Safari.
+button,
+[type="button"], // 1
+[type="reset"],
+[type="submit"] {
+  -webkit-appearance: button; // 2
+}
+
+// Opinionated: add "hand" cursor to non-disabled button elements.
+@if $enable-pointer-cursor-for-buttons {
+  button,
+  [type="button"],
+  [type="reset"],
+  [type="submit"] {
+    &:not(:disabled) {
+      cursor: pointer;
+    }
+  }
+}
+
+// Remove inner border and padding from Firefox, but don't restore the outline like Normalize.
+button::-moz-focus-inner,
+[type="button"]::-moz-focus-inner,
+[type="reset"]::-moz-focus-inner,
+[type="submit"]::-moz-focus-inner {
+  padding: 0;
+  border-style: none;
+}
+
+input[type="radio"],
+input[type="checkbox"] {
+  box-sizing: border-box; // 1. Add the correct box sizing in IE 10-
+  padding: 0; // 2. Remove the padding in IE 10-
+}
+
+
+textarea {
+  overflow: auto; // Remove the default vertical scrollbar in IE.
+  // Textareas should really only resize vertically so they don't break their (horizontal) containers.
+  resize: vertical;
+}
+
+fieldset {
+  // Browsers set a default `min-width: min-content;` on fieldsets,
+  // unlike e.g. `<div>`s, which have `min-width: 0;` by default.
+  // So we reset that to ensure fieldsets behave more like a standard block element.
+  // See https://github.com/twbs/bootstrap/issues/12359
+  // and https://html.spec.whatwg.org/multipage/#the-fieldset-and-legend-elements
+  min-width: 0;
+  // Reset the default outline behavior of fieldsets so they don't affect page layout.
+  padding: 0;
+  margin: 0;
+  border: 0;
+}
+
+// 1. Correct the text wrapping in Edge and IE.
+// 2. Correct the color inheritance from `fieldset` elements in IE.
+legend {
+  display: block;
+  width: 100%;
+  max-width: 100%; // 1
+  padding: 0;
+  margin-bottom: .5rem;
+  @include font-size(1.5rem);
+  line-height: inherit;
+  color: inherit; // 2
+  white-space: normal; // 1
+}
+
+progress {
+  vertical-align: baseline; // Add the correct vertical alignment in Chrome, Firefox, and Opera.
+}
+
+// Correct the cursor style of increment and decrement buttons in Chrome.
+[type="number"]::-webkit-inner-spin-button,
+[type="number"]::-webkit-outer-spin-button {
+  height: auto;
+}
+
+[type="search"] {
+  // This overrides the extra rounded corners on search inputs in iOS so that our
+  // `.form-control` class can properly style them. Note that this cannot simply
+  // be added to `.form-control` as it's not specific enough. For details, see
+  // https://github.com/twbs/bootstrap/issues/11586.
+  outline-offset: -2px; // 2. Correct the outline style in Safari.
+  -webkit-appearance: none;
+}
+
+//
+// Remove the inner padding in Chrome and Safari on macOS.
+//
+
+[type="search"]::-webkit-search-decoration {
+  -webkit-appearance: none;
+}
+
+//
+// 1. Correct the inability to style clickable types in iOS and Safari.
+// 2. Change font properties to `inherit` in Safari.
+//
+
+::-webkit-file-upload-button {
+  font: inherit; // 2
+  -webkit-appearance: button; // 1
+}
+
+//
+// Correct element displays
+//
+
+output {
+  display: inline-block;
+}
+
+summary {
+  display: list-item; // Add the correct display in all browsers
+  cursor: pointer;
+}
+
+template {
+  display: none; // Add the correct display in IE
+}
+
+// Removed a rule that clashes with reveal.js. It was only used in IE anyway.
diff --git a/src/style/bootstrap.scss b/src/style/bootstrap-vendor/bootstrap.scss
similarity index 97%
rename from src/style/bootstrap.scss
rename to src/style/bootstrap-vendor/bootstrap.scss
index 8ac60c182..ebf505667 100644
--- a/src/style/bootstrap.scss
+++ b/src/style/bootstrap-vendor/bootstrap.scss
@@ -11,7 +11,7 @@ Copy of the main bootstrap scss file but without transitions.scss because that c
 @import "~bootstrap/scss/variables";
 @import "~bootstrap/scss/mixins";
 @import "~bootstrap/scss/root";
-@import "~bootstrap/scss/reboot";
+@import "reboot";
 @import "~bootstrap/scss/type";
 @import "~bootstrap/scss/images";
 @import "~bootstrap/scss/code";
diff --git a/src/style/index.scss b/src/style/index.scss
index 9f47c70b3..47fce208c 100644
--- a/src/style/index.scss
+++ b/src/style/index.scss
@@ -6,7 +6,7 @@
 
 @import "variables";
 @import "variables.light";
-@import "bootstrap";
+@import "bootstrap-vendor/bootstrap";
 @import '../../node_modules/react-bootstrap-typeahead/css/Typeahead';
 @import "../../node_modules/@fontsource/source-sans-pro/index";
 @import "../../node_modules/twemoji-colr-font/twemoji";