Refactor `Button` component styling

Handling any deviation from default styling of `Button` components
has been painful, and these changes make it an all or nothing affair:
the `Button` component will apply default styling only in the absence
of a `className` prop. When a `className` prop is present, that will
supersede any component default styling.

These changes make button SCSS mixins clearer and easier to reuse and
extend.

`usePrimaryStyle`, `useCompactStyle`, `useInputStyle` props removed
from `Button` in preference of mixins to reduce `Button` complexity and
confusion over CSS precedence.

Components that use `Button`, and their styles, have been updated here
as needed.

src/sidebar/components/annotation-publish-control.js

@@ -102,7 +102,7 @@ function AnnotationPublishControl({
         icon="cancel"
         buttonText="Cancel"
         onClick={onCancel}
-        useCompactStyle
+        className="annotation-publish-control__btn-cancel"
       />
     </div>
   );

src/sidebar/components/annotation-share-control.js

@@ -87,7 +87,12 @@ function AnnotationShareControl({
 
   return (
     <div className="annotation-share-control" ref={shareRef}>
-      <Button icon="share" title="Share" onClick={toggleSharePanel} />
+      <Button
+        icon="share"
+        title="Share"
+        onClick={toggleSharePanel}
+        isExpanded={isOpen}
+      />
       {isOpen && (
         <div className="annotation-share-panel">
           <div className="annotation-share-panel__header">
@@ -109,8 +114,7 @@ function AnnotationShareControl({
                 icon="copy"
                 title="Copy share link to clipboard"
                 onClick={copyShareLink}
-                useInputStyle
-                useCompactStyle
+                className="annotation-share-panel__icon-button"
               />
             </div>
             <div className="annotation-share-panel__permissions">

src/sidebar/components/button.js

-import classnames from 'classnames';
 import { createElement } from 'preact';
 import propTypes from 'prop-types';
 
 import SvgIcon from '../../shared/components/svg-icon';
 
 /**
- * A button, one of three base types depending on provided props:
- * - Icon-only button: `icon` present, `buttonText` missing
- * - Text-only button: `buttonText` present, `icon` missing
- * - Icon and text: both `icon` and `buttonText` present
+ * A button.
  *
- * Buttons may be additionally styled with 0 to n of (none are mutually exclusive):
- * - `useCompactStyle`: for fitting into tighter spaces
- * - `useInputStyle`: for placing an icon-only button next to an input field
- * - `usePrimaryStyle`: for applying "primary action" styling
- * - `className`: arbitrary additional class name(s) to apply
+ * By default, styling will be applied for the button based on its general
+ * "type" (e.g. an icon-only button, a labeled button). The presence of a
+ * `className` prop will disable all default styling.
  */
 export default function Button({
   buttonText = '',
@@ -26,15 +20,14 @@ export default function Button({
   onClick = () => null,
   style = {},
   title,
-  useCompactStyle = false,
-  useInputStyle = false,
-  usePrimaryStyle = false,
 }) {
   // If `buttonText` is provided, the `title` prop is optional and the `button`'s
   // `title` attribute will be set from the `buttonText`
   title = title || buttonText;
 
-  const baseClassName = buttonText ? 'button--labeled' : 'button--icon-only';
+  const buttonModifier = buttonText ? 'labeled' : 'icon-only';
+  // `className` overrides default class naming when present
+  const baseClassName = className || `button--${buttonModifier}`;
 
   const extraProps = {};
 
@@ -54,23 +47,13 @@ export default function Button({
 
   return (
     <button
-      className={classnames(
-        'button',
-        baseClassName,
-        {
-          'button--compact': useCompactStyle,
-          'button--input': useInputStyle,
-          'button--primary': usePrimaryStyle,
-          'is-active': isPressed,
-        },
-        className
-      )}
+      className={baseClassName}
       onClick={onClick}
       style={style}
       disabled={disabled}
       {...extraProps}
     >
-      {icon && <SvgIcon name={icon} className="button__icon" />}
+      {icon && <SvgIcon name={icon} />}
       {buttonText}
     </button>
   );
@@ -108,9 +91,8 @@ Button.propTypes = {
   buttonText: propTypes.string,
 
   /**
-   * optional CSS classes to add to the `button` element. These classes may
-   * control color, etc., but should not define padding or layout, which are
-   * owned by this component
+   * When present, this will be used as the base class name and will override
+   * all styling. See `buttons` SCSS mixins module for more details.
    */
   className: propTypes.string,
 
@@ -146,16 +128,4 @@ Button.propTypes = {
    * `title`, used for button `title`, is required unless `buttonText` is present
    */
   title: requiredStringIfButtonTextMissing,
-
-  /** Allows a variant of button that takes up less space */
-  useCompactStyle: propTypes.bool,
-
-  /** Allows a variant of button that can sit right next to an input field */
-  useInputStyle: propTypes.bool,
-
-  /**
-   * Does this button represent the "primary" action available? If so,
-   * differentiating styles will be applied.
-   */
-  usePrimaryStyle: propTypes.bool,
 };

src/sidebar/components/login-prompt-panel.js

@@ -30,9 +30,8 @@ export default function LoginPromptPanel({ onLogin, onSignUp }) {
         />
         <Button
           buttonText="Log in"
-          className="sidebar-panel__button"
+          className="sidebar-panel__button--primary"
           onClick={onLogin}
-          usePrimaryStyle
         />
       </div>
     </SidebarPanel>

src/sidebar/components/new-note-btn.js

@@ -30,11 +30,10 @@ function NewNoteButton({ annotationsService, settings }) {
     <div className="new-note-button">
       <Button
         buttonText="New note"
+        className="button--primary"
         icon="add"
         onClick={onNewNoteBtnClick}
         style={applyTheme(['ctaBackgroundColor'], settings)}
-        useCompactStyle
-        usePrimaryStyle
       />
     </div>
   );

src/sidebar/components/search-input.js

@@ -66,7 +66,6 @@ export default function SearchInput({ alwaysExpanded, query, onSearch }) {
           icon="search"
           onClick={() => input.current.focus()}
           title="Search annotations"
-          useCompactStyle
         />
       )}
       {isLoading && <Spinner className="top-bar__btn" title="Loading…" />}

src/sidebar/components/search-status-bar.js

@@ -145,8 +145,7 @@ function SearchStatusBar({ rootThread }) {
             icon="cancel"
             buttonText="Clear search"
             onClick={actions.clearSelection}
-            useCompactStyle
-            usePrimaryStyle
+            className="search-status-bar__button"
           />
           <span className="search-status-bar__filtered-text">
             {modeText.filtered}
@@ -165,8 +164,7 @@ function SearchStatusBar({ rootThread }) {
           <Button
             buttonText={modeText.selected}
             onClick={actions.clearSelection}
-            useCompactStyle
-            usePrimaryStyle
+            className="search-status-bar__button"
           />
         </div>
       )}

src/sidebar/components/share-annotations-panel.js

@@ -80,7 +80,7 @@ function ShareAnnotationsPanel({ analytics, toastMessenger }) {
               icon="copy"
               onClick={copyShareLink}
               title="Copy share link"
-              useInputStyle
+              className="share-annotations-panel__icon-button"
             />
           </div>
           <p>

src/sidebar/components/sidebar-content-error.js

 import { createElement } from 'preact';
+import classnames from 'classnames';
 import propTypes from 'prop-types';
 
 import useStore from '../store/use-store';
@@ -50,17 +51,18 @@ export default function SidebarContentError({
           {showClearSelection && (
             <Button
               buttonText="Show all annotations"
-              className="sidebar-content-error__button"
+              className={classnames({
+                'sidebar-content-error__button': !isLoggedIn,
+                'sidebar-content-error__button--primary': isLoggedIn,
+              })}
               onClick={clearSelection}
-              usePrimaryStyle={isLoggedIn}
             />
           )}
           {!isLoggedIn && (
             <Button
               buttonText="Log in"
-              className="sidebar-content-error__button"
+              className="sidebar-content-error__button--primary"
               onClick={onLoginRequest}
-              usePrimaryStyle
             />
           )}
         </div>

src/sidebar/components/sidebar-panel.js

@@ -57,12 +57,7 @@ export default function SidebarPanel({
           )}
           <h2 className="sidebar-panel__title u-stretch">{title}</h2>
           <div>
-            <Button
-              icon="cancel"
-              buttonText="Close"
-              onClick={closePanel}
-              useCompactStyle
-            />
+            <Button icon="cancel" buttonText="Close" onClick={closePanel} />
           </div>
         </div>
         <div className="sidebar-panel__content">{children}</div>

src/sidebar/components/test/button-test.js

@@ -30,12 +30,6 @@ describe('Button', () => {
     $imports.$restore();
   });
 
-  it('adds active className if `isPressed` is `true`', () => {
-    const wrapper = createComponent({ isPressed: true });
-
-    assert.isTrue(wrapper.find('button').hasClass('is-active'));
-  });
-
   it('renders `SvgIcon` for associated icon', () => {
     const wrapper = createComponent();
     assert.equal(wrapper.find('SvgIcon').prop('name'), 'fakeIcon');
@@ -115,28 +109,26 @@ describe('Button', () => {
     assert.calledOnce(fakeOnClick);
   });
 
-  it('adds additional class name passed in `className` prop', () => {
-    const wrapper = createComponent({ className: 'my-class' });
-
-    assert.isTrue(wrapper.hasClass('my-class'));
-  });
-
-  it('sets compact style if `useCompactStyle` is set`', () => {
-    const wrapper = createComponent({ useCompactStyle: true });
+  it('applies icon-only class if no visible label present', () => {
+    const wrapper = createComponent();
 
-    assert.isTrue(wrapper.find('button').hasClass('button--compact'));
+    assert.isTrue(wrapper.find('button').hasClass('button--icon-only'));
+    assert.isFalse(wrapper.find('button').hasClass('button--labeled'));
   });
 
-  it('sets input style if `useInputStyle` is set', () => {
-    const wrapper = createComponent({ useInputStyle: true });
+  it('applies labeled class if any visible label present', () => {
+    const wrapper = createComponent({ buttonText: 'Some text' });
 
-    assert.isTrue(wrapper.find('button').hasClass('button--input'));
+    assert.isTrue(wrapper.find('button').hasClass('button--labeled'));
+    assert.isFalse(wrapper.find('button').hasClass('button--icon-only'));
   });
 
-  it('sets primary style if `usePrimaryStyle` is set`', () => {
-    const wrapper = createComponent({ usePrimaryStyle: true });
+  it('applies class passed in `className` prop', () => {
+    const wrapper = createComponent({ className: 'my-class' });
 
-    assert.isTrue(wrapper.find('button').hasClass('button--primary'));
+    assert.isTrue(wrapper.find('button').hasClass('my-class'));
+    assert.isFalse(wrapper.hasClass('button--icon-only'));
+    assert.isFalse(wrapper.hasClass('button--labeled'));
   });
 
   it('disables the button when `disabled` prop is true', () => {

src/sidebar/components/test/sidebar-content-error-test.js

@@ -36,9 +36,7 @@ describe('SidebarContentError', () => {
   });
 
   const findButtonByText = (wrapper, text) => {
-    return wrapper
-      .find('.sidebar-content-error__button')
-      .filter({ buttonText: text });
+    return wrapper.find('Button').filter({ buttonText: text });
   };
 
   const errorText = wrapper => {

src/sidebar/components/top-bar.js

@@ -108,7 +108,6 @@ function TopBar({
             isExpanded={currentActivePanel === uiConstants.PANEL_HELP}
             onClick={requestHelp}
             title="Help"
-            useCompactStyle
           />
           {loginControl}
         </div>
@@ -126,7 +125,6 @@ function TopBar({
               title={`Show ${pendingUpdateCount} new/updated ${
                 pendingUpdateCount === 1 ? 'annotation' : 'annotations'
               }`}
-              useCompactStyle
             />
           )}
           <SearchInput query={filterQuery} onSearch={setFilterQuery} />
@@ -140,7 +138,6 @@ function TopBar({
               }
               onClick={toggleSharePanel}
               title="Share annotations on this page"
-              useCompactStyle
             />
           )}
           <Button
@@ -149,7 +146,6 @@ function TopBar({
             isExpanded={currentActivePanel === uiConstants.PANEL_HELP}
             onClick={requestHelp}
             title="Help"
-            useCompactStyle
           />
           {loginControl}
         </div>

src/styles/mixins/buttons.scss

+/**
+ * Button mixins for use by the `Button` component or any component that wishes
+ * to override default `Button`-component styling. These mixins are meant to be
+ * applied to `<button>` HTML elements, with an optional contained icon
+ * (i.e. `SvgIcon` component or `<svg>` element).
+ *
+ * To customize default `Button` styling, start with an appropriate button mixin
+ * and extend or or override rules as necessary in your component's SCSS module.
+ *
+ * e.g., let's pretend you wish the `Button` used in `MyComponent`
+ * to have a pink background. In `my-component.scss`, you might do something like:
+ *
+ * .my-component-button {
+ *    @include button--labeled;
+ *    background-color: pink;
+ * }
+ *
+ * And pass 'my-component-button' as the `className` prop to `Button`.
+ */
 @use "./focus";
 @use "../variables" as var;
 
 @mixin reset-native-btn-styles {
   @include focus.outline-on-keyboard-focus;
 
-  padding: 0px;
-  margin: 0px;
+  padding: 0;
+  margin: 0;
   background-color: transparent;
   border-style: none;
 }
 
 /**
- * Basic color, sizing, padding and hover for any button
+ * Basic color, sizing, padding and hover for buttons.
  */
-@mixin button-base {
+@mixin button {
   @include reset-native-btn-styles;
   padding: 0.5em;
-  color: var.$grey-mid;
 
-  &__icon {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  border-radius: 2px;
+  border: none;
+
+  // Icon
+  svg {
     width: 16px;
     height: 16px;
   }
@@ -27,8 +52,18 @@
     transition: 0.2s ease-out;
     color: var.$grey-7;
   }
+}
 
-  &.is-active {
+/* A button with an icon and no displayed text */
+@mixin button--icon-only {
+  @include button;
+  color: var.$grey-mid;
+  @media (pointer: coarse) {
+    min-width: var.$touch-target-size;
+    min-height: var.$touch-target-size;
+  }
+  &[aria-expanded='true'],
+  &[aria-pressed='true'] {
     color: var.$color-brand;
 
     &:hover {
@@ -37,28 +72,29 @@
   }
 }
 
-/**
- * A button with background color, layout rules to allow an icon, and text settings
- */
-@mixin button-basic {
-  display: flex;
-  align-items: center;
-  border-radius: 2px;
-  border: none;
-  background-color: var.$grey-1;
-  font-weight: 700;
+/* A button with displayed text. It may or may not have an icon. */
+@mixin button--labeled {
+  @include button;
   color: var.$grey-mid;
-
-  padding-right: 0.75em;
-  padding-left: 0.75em;
+  font-weight: 700;
+  background-color: var.$grey-1;
 
   &:hover {
     background-color: var.$grey-2;
   }
+
+  // Icon
+  svg {
+    margin: 0 5px 0 0;
+  }
 }
 
-/* colors for a "primary" button */
-@mixin button-primary {
+/**
+ * A labeled button that is a primary action.
+ */
+@mixin button--primary {
+  @include button;
+  @include button--labeled;
   color: var.$grey-1;
   background-color: var.$grey-mid;
 
@@ -67,3 +103,35 @@
     background-color: var.$grey-6;
   }
 }
+
+/**
+ * An icon-only button that sits to the right of a text-input field
+ * (e.g. "copy to clipboard" button in share panels)
+ */
+@mixin button--input {
+  @include button;
+  color: var.$grey-mid;
+  padding: 0.5em 0.75em;
+  background-color: var.$grey-1;
+
+  border-radius: 0; // Turn off border-radius to align with <input> edges
+  border: 1px solid var.$grey-3;
+  border-left: 0; // Avoid double border with the <input>
+
+  &:hover {
+    background-color: var.$grey-2;
+  }
+}
+
+/**
+ * A button that is styled roughly like an `<a>` element (link-like)
+ */
+@mixin button--link {
+  @include button;
+  color: var.$grey-mid;
+  padding: 0;
+  &:hover {
+    color: var.$color-link-hover;
+    text-decoration: underline;
+  }
+}

src/styles/mixins/panel.scss

-@use "buttons";
 @use "../variables" as var;
+@use "./buttons";
 
 /**
  * Base styles for a "panel"-like element, with appropriate
@@ -46,6 +46,12 @@
   }
 
   &__button {
+    @include buttons.button--labeled;
+    margin-left: 1em;
+  }
+
+  &__button--primary {
+    @include buttons.button--primary;
     margin-left: 1em;
   }
 

src/styles/sidebar/components/annotation-body.scss

 @use '../../variables' as var;
+@use "../../mixins/buttons";
 
 .annotation-body {
   @include var.font-normal;
@@ -38,6 +39,7 @@
   justify-content: flex-end;
 
   .annotation-body__collapse-toggle-button {
+    @include buttons.button--labeled;
     padding: 0.5em;
     background-color: transparent;
   }

src/styles/sidebar/components/annotation-header.scss

+@use "../../mixins/buttons";
 @use "../../mixins/forms";
 @use "../../variables" as var;
 
@@ -17,14 +18,9 @@
     color: var.$color-text;
   }
 
-  &__reply-toggle.button {
+  &__reply-toggle {
+    @include buttons.button--link;
     padding: 0 0.5em;
-    font-weight: 400;
-    background-color: transparent;
-    &:hover {
-      background-color: transparent;
-      color: var.$color-link-hover;
-    }
   }
 
   // Timestamps are right aligned in a flex row

src/styles/sidebar/components/annotation-publish-control.scss

+@use "../../mixins/buttons";
 @use "../../mixins/forms";
 @use "../../variables" as var;
 
@@ -31,6 +32,16 @@
       min-width: 100%;
     }
 
+    &-cancel {
+      @include buttons.button--labeled;
+      padding-right: 0.5em;
+      padding-left: 0.5em;
+
+      &__icon {
+        margin: 0;
+      }
+    }
+
     &-primary {
       @include forms.primary-action-btn;
 

src/styles/sidebar/components/annotation-share-control.scss

+@use '../../mixins/buttons';
 @use '../../mixins/links';
 @use '../../mixins/panel';
 @use "../../variables" as var;
@@ -19,6 +20,15 @@
     display: flex;
   }
 
+  &__icon-button {
+    @include buttons.button--input;
+    padding: 0.25em 0.5em;
+
+    &__icon {
+      margin: 0;
+    }
+  }
+
   & .form-input {
     padding: 0.5em;
     border-radius: 0;

src/styles/sidebar/components/annotation.scss

+@use "../../mixins/buttons";
 @use "../../variables" as var;
 
 // FIXME These hover-related rules should live elsewhere
@@ -37,15 +38,8 @@
     }
   }
 
-  &__reply-toggle.button {
-    background-color: transparent;
-    padding: 0;
-    font-weight: 400;
-
-    &:hover {
-      background-color: transparent;
-      text-decoration: underline;
-    }
+  &__reply-toggle {
+    @include buttons.button--link;
   }
 
   &__controls {

src/styles/sidebar/components/button.scss

@@ -2,73 +2,23 @@
 @use "../../variables" as var;
 
 /**
- * Expected button markup structure:
+ * Button markup structure as generated by the `<Button>` component when
+ * default styles are not overridden:
  *
- * <button class="button <button--icon-only|button--labeled> [button--compact] [button--primary] [is-active]">
- *   [<SvgIcon class="button__icon" />]
+ * <button class="<button--icon-only|button--labeled>">
+ *   [<SvgIcon />]
  *   [<span>label</span>]
  * </button>
  */
-.button {
-  @include buttons.button-base;
-}
-
-.button--labeled {
-  @include buttons.button-basic;
-
-  // Need a little space around the icon if a label is next to it
-  .button__icon {
-    margin: 0 5px;
-  }
-}
-
-/* A button that sits right next to a (text) input and feels "at one" with it */
-.button--input {
-  @include buttons.button-basic;
-  padding: 10px;
-  border-radius: 0; // Turn off border-radius to align with <input> edges
-  border: 1px solid var.$grey-3;
-  border-left: 0px; // Avoid double border with the <input>
-}
-
-// In a few cases, it's necessary to squeeze buttons into tight spots
-.button--compact {
-  // e.g. in the top bar, need to have icons right next to each other
-  &.button--icon-only {
-    padding: 0.25em;
-  }
-
-  // e.g. when next to an input field in a small/tight component
-  &.button--input {
-    padding: 0.25em 0.5em;
-  }
-
-  // e.g. the "close" button for sidebar panels, other tighter spaces
-  &.button--labeled {
-    padding-right: 0.5em;
-    padding-left: 0.5em;
 
-    .button__icon {
-      margin: 0;
-    }
-  }
+.button {
+  @include buttons.button;
 }
 
-.button--primary {
-  @include buttons.button-primary;
+.button--icon-only {
+  @include buttons.button--icon-only;
 }
 
-@media (pointer: coarse) {
-  .button {
-    min-width: var.$touch-target-size;
-    min-height: var.$touch-target-size;
-  }
-
-  // Until the top bar can be refactored to allow for breathing room around
-  // the search interface, we can't spare the room for comfortable tap targets
-  // on touchscreen devices. This overrides `Button`'s larger tap targets.
-  .button--compact {
-    min-width: auto;
-    min-height: auto;
-  }
+.button--labeled {
+  @include buttons.button--labeled;
 }

src/styles/sidebar/components/logged-out-message.scss

+@use "../../mixins/buttons";
 @use "../../variables" as var;
 
 .logged-out-message {
@@ -10,17 +11,11 @@
 }
 
 .logged-out-message__link {
+  @include buttons.button--link;
   padding: 0;
   display: inline;
   color: var.$color-text;
-  background-color: transparent;
   text-decoration: underline;
-  font-weight: 400;
-
-  &:hover {
-    color: var.$color-text;
-    text-decoration: none;
-  }
 }
 
 .logged-out-message__logo {

src/styles/sidebar/components/menu.scss

@@ -23,6 +23,10 @@
     transition: 0.2s ease-out;
     color: var.$color-text;
   }
+  &[aria-expanded='true'],
+  &:hover[aria-expanded='true'] {
+    color: var.$color-brand;
+  }
 }
 
 .menu__toggle-wrapper {
@@ -45,6 +49,7 @@
   &.is-open {
     // Flip the indicator when the menu is open.
     transform: rotateX(180deg);
+    color: var.$color-text;
   }
 }
 

src/styles/sidebar/components/search-status-bar.scss

+@use '../../mixins/buttons';
+
 .search-status-bar {
   display: flex;
   align-items: center;
   margin-bottom: 10px;
 }
 
-.search-status-bar > button {
+.search-status-bar__button {
+  @include buttons.button--primary;
+  padding-right: 0.75em;
   margin-right: 10px;
 }

src/styles/sidebar/components/share-annotations-panel.scss

 @use "../../variables" as var;
-
+@use "../../mixins/buttons";
 @use "../../mixins/links";
 
 .share-annotations-panel {
@@ -23,6 +23,10 @@
     height: 1em;
   }
 
+  &__icon-button {
+    @include buttons.button--input;
+  }
+
   .share-annotations-panel-links {
     @include links.footer-links;
 

src/styles/sidebar/components/tag-editor.scss

@@ -32,7 +32,8 @@
   }
 
   &__delete {
-    @include buttons.button-base;
+    @include buttons.button;
+    color: var.$grey-mid;
     background-color: var.$grey-1;
     padding: 0 0.5em;
     border: 1px solid var.$grey-3;

src/styles/sidebar/components/thread.scss

+@use "../../mixins/buttons";
 @use "../../variables" as var;
 
 .thread {
@@ -30,29 +31,29 @@
     }
   }
 
-  // TODO These styles should be consolidated with other `Button` styles
   &__collapse-button {
+    @include buttons.button;
+    color: var.$grey-mid;
     margin-right: -1.25em;
     padding: 0.25em 0.75em 0.75em 0.75em;
     // Need a non-transparent background so that the dashed border line
     // does not show through the button
     background-color: var.$white;
 
-    .button__icon {
+    svg {
       width: 12px;
       height: 12px;
       color: var.$grey-4;
     }
 
-    &:hover {
-      .button__icon {
+    &:hover &__icon {
       color: var.$grey-6;
     }
   }
-  }
   &__hidden-toggle-button {
     // This makes the vertical alignment with thread-collapse chevrons
     // more precise
+    @include buttons.button--labeled;
     margin-top: -0.25em;
   }
 

src/styles/sidebar/components/top-bar.scss

@@ -3,6 +3,7 @@
 @use "../../variables" as var;
 
 .top-bar {
+  color: var.$grey-mid;
   background: var.$white;
   border-bottom: solid 1px var.$grey-3;
   height: var.$top-bar-height;
@@ -18,8 +19,19 @@
   // the window is scrolled.
   transform: translate3d(0, 0, 0);
 
-  &__icon-button,
-  &__menu-icon {
+  &__icon-button {
+    @include buttons.button--icon-only;
+    padding: 0.25em;
+    @media (pointer: coarse) {
+      // Until the top bar can be refactored to allow for breathing room around
+      // the search interface, we can't spare the room for comfortable tap targets
+      // on touchscreen devices. This overrides `Button`'s larger tap targets.
+      min-width: auto;
+      min-height: auto;
+    }
+  }
+
+  &__icon-button {
     color: var.$grey-mid;
 
     &.is-active {
@@ -48,16 +60,20 @@
   border-bottom: none;
 }
 
-.top-bar__login-button.button {
+.top-bar__login-button {
+  @include buttons.button;
   padding: 0 0.25em;
-  background-color: transparent;
   color: var.$color-brand;
   font-size: var.$body2-font-size;
-  font-weight: 400;
 
   &:hover {
     color: var.$color-link-hover;
   }
+
+  @media (pointer: coarse) {
+    min-width: inherit;
+    min-height: inherit;
+  }
 }
 
 .top-bar__login-links {

src/styles/sidebar/components/version-info.scss

 @use "../../variables" as var;
 
-@use "../../mixins/buttons";
-
 .version-info {
   margin-top: 0.5em;