8 files changed, 1056 insertions, 0 deletions
diff --git a/assets/sass/@primer/css/forms/README.md b/assets/sass/@primer/css/forms/README.md
new file mode 100644
index 0000000..e092504
--- /dev/null
+++ b/assets/sass/@primer/css/forms/README.md
@@ -0,0 +1,25 @@
+---
+bundle: "forms"
+generated: true
+---
+
+# Primer CSS: `forms` bundle
+
+## Usage
+
+Primer CSS source files are written in [SCSS]. To include this Primer CSS module in your own build, ensure that your `node_modules` directory is listed in your Sass include paths, then import it with:
+
+```scss
+@import "@primer/css/forms/index.scss";
+```
+
+## Build
+
+The `@primer/css` npm package includes a standalone CSS build of this module in `dist/forms.css`.
+
+## License
+
+[MIT](https://github.com/primer/css/blob/master/LICENSE) &copy; [GitHub](https://github.com/)
+
+
+[scss]: https://sass-lang.com/documentation/syntax#scss
diff --git a/assets/sass/@primer/css/forms/form-control.scss b/assets/sass/@primer/css/forms/form-control.scss
new file mode 100644
index 0000000..778f320
--- /dev/null
+++ b/assets/sass/@primer/css/forms/form-control.scss
@@ -0,0 +1,259 @@
+// Needs refactoring
+// stylelint-disable selector-no-qualifying-type, selector-max-compound-selectors
+// stylelint-disable selector-max-type
+// Base form controls
+//
+// Overrides for common inputs for easier styling.
+
+fieldset {
+  padding: 0;
+  margin: 0;
+  border: 0;
+}
+
+label {
+  font-weight: $font-weight-bold;
+}
+
+.form-control,
+.form-select {
+  min-height: 34px;
+  // stylelint-disable-next-line primer/spacing
+  padding: 6px $spacer-2;
+  font-size: $h4-size;
+  // stylelint-disable-next-line primer/typography
+  line-height: 20px;
+  color: $text-gray-dark;
+  vertical-align: middle;
+  background-color: $bg-white;
+  background-repeat: no-repeat; // Repeat and position set for form states (success, error, etc)
+  background-position: right 8px center; // For form validation. This keeps images 8px from right and centered vertically.
+  border: $border-width $border-style $border-gray-dark;
+  border-radius: $border-radius;
+  outline: none;
+  box-shadow: $form-control-shadow;
+
+  &.focus,
+  &:focus {
+    // stylelint-disable-next-line primer/borders
+    border-color: $blue-400;
+    outline: none;
+    box-shadow: $form-control-shadow, $btn-input-focus-shadow;
+  }
+
+  // Ensures inputs don't zoom on mobile but are body-font size on desktop
+  @include breakpoint(md) {
+    font-size: $body-font-size;
+  }
+}
+
+// Inputs with contrast for easy light gray backgrounds against white.
+.input-contrast {
+  background-color: $bg-gray-light;
+
+  &:focus { background-color: $bg-white; }
+}
+
+// Inputs to be used against dark backgrounds.
+.input-dark {
+  color: $text-white;
+  // stylelint-disable-next-line primer/colors
+  background-color: $white-fade-15;
+  border-color: transparent;
+
+  &::placeholder {
+    color: inherit;
+    opacity: 0.6; // inceases contrast ratio to 4.52
+  }
+
+  &.focus,
+  &:focus {
+    // stylelint-disable-next-line primer/borders
+    border-color: $black-fade-30;
+    // stylelint-disable-next-line primer/box-shadow
+    box-shadow: 0 0 0 0.2em rgba($blue-300, 0.4);
+  }
+}
+
+// Custom styling for HTML5 validation bubbles (WebKit only)
+::placeholder {
+  color: $text-gray-light;
+}
+
+// Mini inputs, to match .minibutton
+.input-sm {
+  min-height: 28px;
+  // stylelint-disable-next-line primer/spacing
+  padding-top: 3px;
+  // stylelint-disable-next-line primer/spacing
+  padding-bottom: 3px;
+  font-size: $font-size-small;
+  // stylelint-disable-next-line primer/typography
+  line-height: 20px;
+}
+
+// Large inputs
+.input-lg {
+  padding: $spacer-1 10px;
+  font-size: $h4-size;
+}
+
+// Full-width inputs
+.input-block {
+  display: block;
+  width: 100%;
+}
+
+// Inputs with monospace text
+.input-monospace {
+  font-family: $mono-font;
+}
+
+// Hide the icon that tries to autofill contact info in webkit
+.input-hide-webkit-autofill {
+  &::-webkit-contacts-auto-fill-button {
+    position: absolute;
+    right: 0;
+    display: none !important;
+    pointer-events: none;
+    visibility: hidden;
+  }
+}
+
+// Checkboxes and Radiobuttons
+//
+// For checkboxes and radio button selections.
+.form-checkbox {
+  // stylelint-disable-next-line primer/spacing
+  padding-left: 20px;
+  // stylelint-disable-next-line primer/spacing
+  margin: 15px 0;
+  vertical-align: middle;
+
+  label {
+    em.highlight {
+      position: relative;
+      left: -$spacer-1;
+      // stylelint-disable-next-line primer/spacing
+      padding: 2px $spacer-1;
+      font-style: normal;
+      // stylelint-disable-next-line primer/colors
+      background: $yellow-100;
+      border-radius: $border-radius;
+    }
+  }
+
+  input[type=checkbox],
+  input[type=radio] {
+    float: left;
+    // stylelint-disable-next-line primer/spacing
+    margin: 5px 0 0 -20px;
+    vertical-align: middle;
+  }
+
+  .note {
+    display: block;
+    margin: 0;
+    font-size: $font-size-small;
+    font-weight: $font-weight-normal;
+    color: $text-gray;
+  }
+}
+
+.form-checkbox-details {
+  display: none;
+}
+
+.form-checkbox-details-trigger {
+  &:checked {
+    // child of sibling or sibling
+    ~ * .form-checkbox-details,
+    ~ .form-checkbox-details { // eslint-disable selector-combinator-space-before
+      display: block;
+    }
+  }
+}
+
+// Field groups
+//
+// Wrap field groups in `<div.hfields>` to lay them out horizontally - great for
+// the top of pages with autosave.
+.hfields {
+  // stylelint-disable-next-line primer/spacing
+  margin: 15px 0;
+  @include clearfix;
+
+  .form-group {
+    float: left;
+    // stylelint-disable-next-line primer/spacing
+    margin: 0 30px 0 0;
+
+    dt, // TODO: Deprecate
+    .form-group-header {
+      label {
+        display: inline-block;
+        // stylelint-disable-next-line primer/spacing
+        margin: 5px 0 0;
+        color: $text-gray;
+      }
+
+      img {
+        position: relative;
+        top: -2px;
+      }
+    }
+  }
+
+  .btn {
+    float: left;
+    // stylelint-disable-next-line primer/spacing
+    margin: 28px 25px 0 -20px;
+  }
+
+  // stylelint-disable-next-line primer/spacing
+  .form-select { margin-top: 5px; }
+}
+
+// Hide the up/down buttons in <input type="number"> in the login form, the
+// input is used for two-factor auth codes, type="number" makes it more usable
+// on phones
+input::-webkit-outer-spin-button,
+input::-webkit-inner-spin-button {
+  margin: 0;
+  appearance: none;
+}
+
+// Input groups
+
+.form-actions {
+  @include clearfix;
+
+  .btn {
+    float: right;
+
+    + .btn {
+      // stylelint-disable-next-line primer/spacing
+      margin-right: 5px;
+    }
+  }
+}
+
+.form-warning {
+  padding: $spacer-2 10px;
+  // stylelint-disable-next-line primer/spacing
+  margin: 10px 0;
+  font-size: $h5-size;
+  // stylelint-disable-next-line primer/colors
+  color: $yellow-900;
+  // stylelint-disable-next-line primer/colors
+  background: $yellow-100;
+  border: $border-width $border-style $border-yellow;
+  border-radius: $border-radius;
+
+  p {
+    margin: 0;
+    line-height: $lh-default;
+  }
+
+  a { font-weight: $font-weight-bold; }
+}
diff --git a/assets/sass/@primer/css/forms/form-group.scss b/assets/sass/@primer/css/forms/form-group.scss
new file mode 100644
index 0000000..c8db050
--- /dev/null
+++ b/assets/sass/@primer/css/forms/form-group.scss
@@ -0,0 +1,265 @@
+// stylelint-disable selector-max-compound-selectors
+// stylelint-disable selector-max-type
+
+// Form groups
+//
+// Usage:
+//
+// <div class="form-group">
+//   <div class="form-group-header"> containing the label
+//   <div class="form-group-body"> containing the form elements
+// </div>
+
+.form-group {
+  // stylelint-disable-next-line primer/spacing
+  margin: 15px 0;
+
+  // Text fields
+  .form-control {
+    width: 440px;
+    max-width: 100%;
+    // stylelint-disable-next-line primer/spacing
+    margin-right: 5px;
+    background-color: $bg-gray-light;
+
+    &:focus {
+      background-color: $bg-white;
+    }
+
+    &.shorter { width: 130px; }
+
+    &.short { width: 250px; }
+
+    &.long { width: 100%; }
+  }
+
+  // Textarea
+  // stylelint-disable selector-no-qualifying-type
+  textarea.form-control {
+    width: 100%;
+    height: 200px;
+    min-height: 200px;
+
+    &.short {
+      height: 50px;
+      min-height: 50px;
+    }
+  }
+  // stylelint-enable selector-no-qualifying-type
+
+  // The Label
+  dt, // TODO: Deprecate
+  .form-group-header {
+    // stylelint-disable-next-line primer/spacing
+    margin: 0 0 6px;
+  }
+
+  label {
+    position: relative;
+  }
+
+  &.flattened dt, // TODO: Deprecate
+  &.flattened .form-group-header {
+    float: left;
+    margin: 0;
+    // stylelint-disable-next-line primer/typography
+    line-height: 32px;
+  }
+
+  &.flattened dd, // TODO: Deprecate
+  &.flattened .form-group-body {
+    // stylelint-disable-next-line primer/typography
+    line-height: 32px;
+  }
+
+  //
+  // Form Elements
+  //
+  // stylelint-disable selector-no-qualifying-type
+  dd, // TODO: Deprecate
+  .form-group-body {
+    h4 {
+      margin: $spacer-1 0 0;
+
+      &.is-error { color: $text-red; }
+
+      &.is-success { color: $text-green; }
+
+      + .note {
+        margin-top: 0;
+      }
+    }
+  }
+  // stylelint-enable selector-no-qualifying-type
+
+  //
+  // Variants
+  //
+
+  &.required {
+    dt label::after, // TODO: Deprecate
+    .form-group-header label::after {
+      // stylelint-disable-next-line primer/spacing
+      padding-left: 5px;
+      color: $text-red;
+      content: "*";
+    }
+  }
+
+  // Form AJAX states
+  //
+  // Form fields that need feedback for AJAX loading, success
+  // states and errored states.
+  .success,
+  .error,
+  .indicator {
+    display: none;
+    font-size: $font-size-small;
+    font-weight: $font-weight-bold;
+  }
+
+  &.loading {
+    opacity: 0.5;
+
+    .indicator {
+      display: inline;
+    }
+
+    .spinner {
+      display: inline-block;
+      vertical-align: middle;
+    }
+  }
+
+  &.successful {
+    .success {
+      display: inline;
+      color: $text-green;
+    }
+  }
+
+  // Form validation
+  //
+  // Our inline errors
+
+  &.successed,
+  &.warn,
+  &.errored {
+    .success,
+    .warning,
+    .error {
+      position: absolute;
+      z-index: 10;
+      display: block; // Show up in errored/warn state
+      max-width: 450px; // Keep our long errors readable
+      // stylelint-disable-next-line primer/spacing
+      padding: 5px $spacer-2;
+      margin: $spacer-1 0 0;
+      // stylelint-disable-next-line primer/typography
+      font-size: 13px;
+      font-weight: $font-weight-normal;
+      border-style: $border-style;
+      border-width: $border-width;
+      border-radius: $border-radius;
+
+      &::after,
+      &::before {
+        position: absolute;
+        bottom: 100%;
+        left: 10px;
+        z-index: 15;
+        width: 0;
+        height: 0;
+        pointer-events: none;
+        content: " ";
+        // stylelint-disable-next-line primer/borders
+        border: $border-style transparent;
+      }
+
+      &::after {
+        // stylelint-disable-next-line primer/borders
+        border-width: 5px;
+      }
+
+      &::before {
+        // stylelint-disable-next-line primer/spacing
+        margin-left: -1px;
+        // stylelint-disable-next-line primer/borders
+        border-width: 6px;
+      }
+    }
+  }
+
+  &.successed {
+    .success {
+      // stylelint-disable-next-line primer/colors
+      color: $green-900;
+      // stylelint-disable-next-line primer/colors
+      background-color: $green-100;
+      border-color: $border-green;
+
+      &::after {
+        // stylelint-disable-next-line primer/borders
+        border-bottom-color: $green-100;
+      }
+
+      &::before {
+        border-bottom-color: $border-green;
+      }
+    }
+  }
+
+  &.warn {
+    .warning {
+      // stylelint-disable-next-line primer/colors
+      color: $yellow-900;
+      // stylelint-disable-next-line primer/colors
+      background-color: $yellow-100;
+      border-color: $border-yellow;
+
+      &::after {
+        // stylelint-disable-next-line primer/borders
+        border-bottom-color: $yellow-100;
+      }
+
+      &::before {
+        border-bottom-color: $border-yellow;
+      }
+    }
+  }
+
+  &.errored {
+    label {
+      color: $text-red;
+    }
+
+    .error {
+      // stylelint-disable-next-line primer/colors
+      color: $red-900;
+      background-color: $bg-red-light;
+      border-color: $border-red-light;
+
+      &::after {
+        // stylelint-disable-next-line primer/borders
+        border-bottom-color: $bg-red-light;
+      }
+
+      &::before {
+        border-bottom-color: $border-red-light;
+      }
+    }
+  }
+}
+
+.note {
+  min-height: 17px;
+  margin: $spacer-1 0 2px;
+  font-size: $font-size-small;
+  color: $text-gray;
+
+  .spinner {
+    // stylelint-disable-next-line primer/spacing
+    margin-right: 3px;
+    vertical-align: middle;
+  }
+}
diff --git a/assets/sass/@primer/css/forms/form-select.scss b/assets/sass/@primer/css/forms/form-select.scss
new file mode 100644
index 0000000..ac98967
--- /dev/null
+++ b/assets/sass/@primer/css/forms/form-select.scss
@@ -0,0 +1,39 @@
+// Custom select
+//
+// Apply `.select` to any `<select>` element for custom styles.
+.form-select {
+  display: inline-block;
+  max-width: 100%;
+  height: 34px;
+  padding-right: $spacer-4;
+  background-color: $bg-white;
+  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAUCAMAAACzvE1FAAAADFBMVEUzMzMzMzMzMzMzMzMKAG/3AAAAA3RSTlMAf4C/aSLHAAAAPElEQVR42q3NMQ4AIAgEQTn//2cLdRKppSGzBYwzVXvznNWs8C58CiussPJj8h6NwgorrKRdTvuV9v16Afn0AYFOB7aYAAAAAElFTkSuQmCC");
+  background-repeat: no-repeat;
+  background-position: right 8px center;
+  background-size: 8px 10px;
+  appearance: none;
+
+  // Hides the default caret in IE11
+  &::-ms-expand {
+    opacity: 0;
+  }
+
+  &[multiple] {
+    height: auto;
+  }
+}
+
+.select-sm {
+  height: 28px;
+  min-height: 28px;
+  // stylelint-disable-next-line primer/spacing
+  padding-top: 3px;
+  // stylelint-disable-next-line primer/spacing
+  padding-bottom: 3px;
+  font-size: $font-size-small;
+
+  &[multiple] {
+    height: auto;
+    min-height: 0;
+  }
+}
diff --git a/assets/sass/@primer/css/forms/form-validation.scss b/assets/sass/@primer/css/forms/form-validation.scss
new file mode 100644
index 0000000..a6b49c8
--- /dev/null
+++ b/assets/sass/@primer/css/forms/form-validation.scss
@@ -0,0 +1,365 @@
+// Needs refactoring
+// stylelint-disable selector-no-qualifying-type, selector-max-type
+dl.form-group > dd, // TODO: Deprecate
+.form-group > .form-group-body {
+  .form-control {
+    &.is-autocheck-loading,
+    &.is-autocheck-successful,
+    &.is-autocheck-errored {
+      // stylelint-disable-next-line primer/spacing
+      padding-right: 30px; // Leave some space for our validation icons
+    }
+
+    &.is-autocheck-loading {
+      background-image: url("/images/spinners/octocat-spinner-16px.gif");
+    }
+
+    &.is-autocheck-successful {
+      background-image: url("/images/modules/ajax/success.png");
+    }
+
+    &.is-autocheck-errored {
+      background-image: url("/images/modules/ajax/error.png");
+    }
+  }
+}
+
+// Retinization of form validation icons that aren't octicons yet
+@include retina-media-query {
+  dl.form-group > dd, // TODO: Deprecate
+  .form-group > .form-group-body {
+    .form-control {
+      &.is-autocheck-loading,
+      &.is-autocheck-successful,
+      &.is-autocheck-errored {
+        background-size: 16px 16px;
+      }
+
+      &.is-autocheck-loading {
+        background-image: url("/images/spinners/octocat-spinner-32.gif");
+      }
+
+      &.is-autocheck-successful {
+        background-image: url("/images/modules/ajax/success@2x.png");
+      }
+
+      &.is-autocheck-errored {
+        background-image: url("/images/modules/ajax/error@2x.png");
+      }
+    }
+  }
+}
+
+// Inline verification
+// This overrides primer's inline form stuff
+.status-indicator {
+  display: inline-block;
+  width: 16px;
+  height: 16px;
+  // stylelint-disable-next-line primer/spacing
+  margin-left: 5px;
+
+  .octicon {
+    display: none;
+  }
+}
+
+.status-indicator-success {
+  // Override primer
+  &::before {
+    content: "";
+  }
+
+  .octicon-check {
+    display: inline-block;
+    // stylelint-disable-next-line primer/colors
+    color: $green;
+    fill: $green;
+  }
+
+  .octicon-x {
+    display: none;
+  }
+}
+
+.status-indicator-failed {
+  // Override primer
+  &::before {
+    content: "";
+  }
+
+  .octicon-check {
+    display: none;
+  }
+
+  .octicon-x {
+    display: inline-block;
+    color: $text-red;
+    fill: $red;
+  }
+}
+
+.status-indicator-loading {
+  width: 16px;
+  background-image: url("/images/spinners/octocat-spinner-32-EAF2F5.gif");
+  background-repeat: no-repeat;
+  background-position: 0 0;
+  background-size: 16px;
+}
+
+.inline-form {
+  display: inline-block;
+
+  .btn-plain {
+    background-color: transparent;
+    border: 0;
+  }
+}
+
+// Drag and drop
+//
+// Previously part of `_forms.scss` in Primer. Needs accounting for.
+
+.drag-and-drop {
+  // stylelint-disable-next-line primer/spacing
+  padding: 7px 10px;
+  margin: 0;
+  // stylelint-disable-next-line primer/typography
+  font-size: 13px;
+  // stylelint-disable-next-line primer/typography
+  line-height: 16px;
+  color: $text-gray;
+  background-color: $bg-gray-light;
+  // stylelint-disable-next-line primer/borders
+  border: $border-width $border-style darken($gray-300, 5%);
+  border-top: 0;
+  border-bottom-right-radius: $border-radius;
+  border-bottom-left-radius: $border-radius;
+
+  .default,
+  .loading,
+  .error {
+    display: none;
+  }
+
+  .error {
+    color: $text-red;
+  }
+
+  // Spinner
+  img {
+    vertical-align: top;
+  }
+}
+
+.is-default .drag-and-drop .default {
+  display: inline-block;
+}
+
+.is-uploading .drag-and-drop .loading {
+  display: inline-block;
+}
+
+.is-bad-file .drag-and-drop .bad-file {
+  display: inline-block;
+}
+
+.is-duplicate-filename .drag-and-drop .duplicate-filename {
+  display: inline-block;
+}
+
+.is-too-big .drag-and-drop .too-big {
+  display: inline-block;
+}
+
+.is-hidden-file .drag-and-drop .hidden-file {
+  display: inline-block;
+}
+
+.is-empty .drag-and-drop .empty {
+  display: inline-block;
+}
+
+.is-bad-permissions .drag-and-drop .bad-permissions {
+  display: inline-block;
+}
+
+.is-repository-required .drag-and-drop .repository-required {
+  display: inline-block;
+}
+
+.drag-and-drop-error-info {
+  font-weight: $font-weight-normal;
+  color: $text-gray;
+
+  a {
+    color: $text-blue;
+  }
+}
+
+.is-failed .drag-and-drop .failed-request {
+  display: inline-block;
+}
+
+.manual-file-chooser {
+  position: absolute;
+  width: 240px;
+  // stylelint-disable-next-line primer/spacing
+  padding: 5px;
+  // stylelint-disable-next-line primer/spacing
+  margin-left: -80px;
+  cursor: pointer;
+  opacity: 0.0001;
+}
+
+.manual-file-chooser:hover + .manual-file-chooser-text {
+  text-decoration: underline;
+}
+
+.btn {
+  // align manual-file-chooser inside a button
+  .manual-file-chooser {
+    top: 0;
+    padding: 0;
+    // stylelint-disable-next-line primer/typography
+    line-height: 34px;
+  }
+}
+
+// Focused Textarea styles
+.upload-enabled {
+  textarea {
+    display: block;
+    // stylelint-disable-next-line primer/borders
+    border-bottom: $border-width dashed lighten($gray-300, 5%);
+    border-bottom-right-radius: 0;
+    border-bottom-left-radius: 0;
+  }
+
+  &.focused {
+    border-radius: $border-radius;
+    box-shadow: $form-control-shadow, $btn-input-focus-shadow;
+
+    .form-control {
+      box-shadow: none;
+    }
+
+    .drag-and-drop {
+      // stylelint-disable-next-line primer/borders
+      border-color: lighten($blue-400, 8%);
+    }
+  }
+}
+
+// Dropping a file on top
+.dragover textarea,
+.dragover .drag-and-drop {
+  // stylelint-disable-next-line primer/box-shadow
+  box-shadow: rgba(#c9ff00, 1) 0 0 3px;
+}
+
+.write-content {
+  position: relative;
+}
+
+// Form style with a write and a preview tab
+.previewable-comment-form {
+  position: relative;
+
+  .tabnav {
+    position: relative;
+    padding: $spacer-2 $spacer-2 0;
+  }
+
+  .comment {
+    // stylelint-disable-next-line primer/borders
+    border: $border-width $border-style darken($gray-300, 5%);
+  }
+
+  .comment-form-error { margin-bottom: $spacer-2; }
+
+  .write-content,
+  .preview-content {
+    display: none;
+    margin: 0 $spacer-2 $spacer-2;
+  }
+
+  &.write-selected .write-content,
+  &.preview-selected .preview-content {
+    display: block;
+  }
+
+  textarea {
+    display: block;
+    width: 100%;
+    min-height: 100px;
+    max-height: 500px;
+    padding: $spacer-2;
+    resize: vertical;
+  }
+}
+
+// Used in our boxed-group-less form styles. Give the sumbit button enough space
+// to breathe without the need for the extra hr.
+.form-action-spacious {
+  // stylelint-disable-next-line primer/spacing
+  margin-top: 10px;
+}
+
+// A two column form, with a .main and a .sidebar column
+//
+// Override some `.timeline-comment-wrapper` defaults.
+// The `div` is needed to be more specific than the other class.
+div.composer {
+  margin-top: 0;
+  border: 0;
+}
+
+// Override the previewable comment form defaults
+.composer .comment-form-textarea {
+  height: 200px;
+  min-height: 200px;
+}
+
+// stylelint-disable-next-line primer/spacing
+.composer .tabnav { margin: 0 0 10px; }
+
+// Misc CSS
+//
+// Previously part of `_forms.scss` in Primer. Needs accounting for.
+
+h2.account {
+  // stylelint-disable-next-line primer/spacing
+  margin: 15px 0 0;
+  // stylelint-disable-next-line primer/typography
+  font-size: 18px;
+  font-weight: $font-weight-normal;
+  color: $text-gray;
+}
+
+p.explain {
+  position: relative;
+  font-size: $font-size-small;
+  color: $text-gray;
+
+  strong {
+    color: $text-gray-dark;
+  }
+
+  .octicon {
+    // stylelint-disable-next-line primer/spacing
+    margin-right: 5px;
+    // stylelint-disable-next-line primer/colors
+    color: $gray-400;
+  }
+
+  .minibutton {
+    top: -4px;
+    float: right;
+  }
+}
+
+// fix for chrome bug, see https://github.com/github/github/issues/53931
+.form-group label {
+  position: static;
+}
diff --git a/assets/sass/@primer/css/forms/index.scss b/assets/sass/@primer/css/forms/index.scss
new file mode 100644
index 0000000..aab50b7
--- /dev/null
+++ b/assets/sass/@primer/css/forms/index.scss
@@ -0,0 +1,7 @@
+@import "../support/index.scss";
+@import "./form-control.scss";
+@import "./form-select.scss";
+@import "./form-group.scss";
+@import "./form-validation.scss";
+@import "./input-group.scss";
+@import "./radio-group.scss";
diff --git a/assets/sass/@primer/css/forms/input-group.scss b/assets/sass/@primer/css/forms/input-group.scss
new file mode 100644
index 0000000..7cae4ee
--- /dev/null
+++ b/assets/sass/@primer/css/forms/input-group.scss
@@ -0,0 +1,53 @@
+.input-group {
+  display: table;
+
+  .form-control {
+    position: relative;
+    width: 100%;
+
+    &:focus {
+      z-index: 2;
+    }
+
+    + .btn {
+      margin-left: 0;
+    }
+  }
+
+  // For when you want the input group to behave like inline-block.
+  &.inline {
+    display: inline-table;
+  }
+}
+
+.input-group .form-control,
+.input-group-button {
+  display: table-cell;
+}
+
+.input-group-button {
+  width: 1%;
+  vertical-align: middle; // Match the inputs
+}
+
+.input-group .form-control:first-child,
+.input-group-button:first-child .btn {
+  border-top-right-radius: 0;
+  border-bottom-right-radius: 0;
+}
+
+.input-group-button:first-child .btn {
+  // stylelint-disable-next-line primer/spacing
+  margin-right: -1px;
+}
+
+.input-group .form-control:last-child,
+.input-group-button:last-child .btn {
+  border-top-left-radius: 0;
+  border-bottom-left-radius: 0;
+}
+
+.input-group-button:last-child .btn {
+  // stylelint-disable-next-line primer/spacing
+  margin-left: -1px;
+}
diff --git a/assets/sass/@primer/css/forms/radio-group.scss b/assets/sass/@primer/css/forms/radio-group.scss
new file mode 100644
index 0000000..fb6c0cd
--- /dev/null
+++ b/assets/sass/@primer/css/forms/radio-group.scss
@@ -0,0 +1,43 @@
+// Tab like radio group
+
+.radio-group {
+  @include clearfix;
+}
+
+.radio-label {
+  float: left;
+  // stylelint-disable-next-line primer/spacing
+  padding: 6px $spacer-3 6px ($spacer-3 + 12px + $spacer-2); // 12px is the size of the radio-input
+  // stylelint-disable-next-line primer/spacing
+  margin-left: -1px;
+  font-size: $body-font-size;
+  // stylelint-disable-next-line primer/typography
+  line-height: 20px; // Specifically not inherit our `<body>` default
+  color: $text-gray-dark;
+  cursor: pointer;
+  border: $border-width $border-style $border-gray-dark;
+
+  :checked + & {
+    position: relative;
+    z-index: 1;
+    border-color: $border-blue;
+  }
+
+  &:first-of-type {
+    margin-left: 0;
+    border-top-left-radius: $border-radius;
+    border-bottom-left-radius: $border-radius;
+  }
+
+  &:last-of-type {
+    border-top-right-radius: $border-radius;
+    border-bottom-right-radius: $border-radius;
+  }
+}
+
+.radio-input {
+  z-index: 3;
+  float: left;
+  // stylelint-disable-next-line primer/spacing
+  margin: 10px (-$spacer-5) 0 $spacer-3;
+}