diff --git a/web/chat/chat-input-bar.css b/web/chat/chat-input-bar.css
index 4313ea27e..6a21cb9f4 100644
--- a/web/chat/chat-input-bar.css
+++ b/web/chat/chat-input-bar.css
@@ -1,105 +1,85 @@
 div.inputBar {
   display: flex;
   flex-direction: column;
   border-top: 1px solid var(--border-color);
 }
 div.inputBarWrapper {
   padding: 16px;
   display: flex;
   flex-direction: row;
   align-items: center;
 }
 div.inputBarTextInput {
   display: flex;
   background: var(--text-input-bg);
   border-radius: 4px;
   padding: 8px;
   align-items: center;
   flex-grow: 1;
 }
 div.inputBarTextInput > textarea {
   flex: 1;
   display: flex;
   border: none;
   resize: none;
   background: var(--text-input-bg);
   color: var(--fg);
 }
 div.inputBarTextInput > textarea:focus {
   outline: none;
 }
 div.joinButtonContainer {
   background: var(--join-bg);
   padding-top: 8px;
   padding-bottom: 8px;
   display: flex;
   flex-direction: row;
   width: 100%;
   justify-content: center;
 }
-button.joinButton {
-  display: flex;
-  align-items: center;
-  border: none;
-  padding: 12px 24px;
-  border-radius: 4px;
-  color: var(--fg);
-  font-size: var(--m-font-16);
-  font-weight: var(--semi-bold);
-  cursor: pointer;
-}
-
-button.joinButton {
-  display: flex;
-  border-radius: 4px;
-  justify-content: center;
-  cursor: pointer;
-}
 p.joinButtonText {
-  font-size: var(--m-font-16);
   font-weight: var(--semi-bold);
-  color: var(--fg);
   padding-left: 8px;
 }
 span.explanation {
   color: var(--permission-color);
   text-align: center;
   padding-top: 20px;
   padding-bottom: 8px;
 }
 a.multimediaUpload {
   cursor: pointer;
   position: relative;
   padding-right: 12px;
 }
 a.multimediaUpload > input[type='file'] {
   visibility: hidden;
   position: absolute;
   top: 0;
   bottom: 0;
   left: 0;
   right: 0;
   margin: 0;
   padding: 0;
 }
 a.multimediaUpload:hover > svg {
   opacity: 0.8;
 }
 
 div.previews {
   display: flex;
   overflow-x: auto;
   white-space: nowrap;
 }
 div.previews > span.multimedia {
   margin: 10px;
 }
 div.previews > span.multimedia > span.multimediaImage > img {
   max-height: 200px;
   max-width: 200px;
 }
 
 a.sendButton {
   padding: 8px 0 0 10px;
   cursor: pointer;
 }
diff --git a/web/chat/chat-input-bar.react.js b/web/chat/chat-input-bar.react.js
index 2647a858a..cb9d7463d 100644
--- a/web/chat/chat-input-bar.react.js
+++ b/web/chat/chat-input-bar.react.js
@@ -1,483 +1,483 @@
 // @flow
 
 import invariant from 'invariant';
 import _difference from 'lodash/fp/difference';
 import * as React from 'react';
 
 import {
   joinThreadActionTypes,
   joinThread,
   newThreadActionTypes,
 } from 'lib/actions/thread-actions';
 import { createLoadingStatusSelector } from 'lib/selectors/loading-selectors';
 import { localIDPrefix, trimMessage } from 'lib/shared/message-utils';
 import {
   threadHasPermission,
   viewerIsMember,
   threadFrozenDueToViewerBlock,
   threadActualMembers,
   checkIfDefaultMembersAreVoiced,
 } from 'lib/shared/thread-utils';
 import type { CalendarQuery } from 'lib/types/entry-types';
 import type { LoadingStatus } from 'lib/types/loading-types';
 import { messageTypes } from 'lib/types/message-types';
 import {
   type ThreadInfo,
   threadPermissions,
   type ClientThreadJoinRequest,
   type ThreadJoinPayload,
 } from 'lib/types/thread-types';
 import { type UserInfos } from 'lib/types/user-types';
 import {
   type DispatchActionPromise,
   useServerCall,
   useDispatchActionPromise,
 } from 'lib/utils/action-utils';
 
+import Button from '../components/button.react';
 import {
   type InputState,
   type PendingMultimediaUpload,
 } from '../input/input-state';
 import LoadingIndicator from '../loading-indicator.react';
 import { allowedMimeTypeString } from '../media/file-utils';
 import Multimedia from '../media/multimedia.react';
 import { useSelector } from '../redux/redux-utils';
 import { nonThreadCalendarQuery } from '../selectors/nav-selectors';
 import SWMansionIcon from '../SWMansionIcon.react';
 import css from './chat-input-bar.css';
 
 type BaseProps = {
   +threadInfo: ThreadInfo,
   +inputState: InputState,
 };
 type Props = {
   ...BaseProps,
   // Redux state
   +viewerID: ?string,
   +joinThreadLoadingStatus: LoadingStatus,
   +threadCreationInProgress: boolean,
   +calendarQuery: () => CalendarQuery,
   +nextLocalID: number,
   +isThreadActive: boolean,
   +userInfos: UserInfos,
   // Redux dispatch functions
   +dispatchActionPromise: DispatchActionPromise,
   // async functions that hit server APIs
   +joinThread: (request: ClientThreadJoinRequest) => Promise<ThreadJoinPayload>,
 };
 class ChatInputBar extends React.PureComponent<Props> {
   textarea: ?HTMLTextAreaElement;
   multimediaInput: ?HTMLInputElement;
 
   componentDidMount() {
     this.updateHeight();
     if (this.props.isThreadActive) {
       this.addReplyListener();
     }
   }
 
   componentWillUnmount() {
     if (this.props.isThreadActive) {
       this.removeReplyListener();
     }
   }
 
   componentDidUpdate(prevProps: Props) {
     if (this.props.isThreadActive && !prevProps.isThreadActive) {
       this.addReplyListener();
     } else if (!this.props.isThreadActive && prevProps.isThreadActive) {
       this.removeReplyListener();
     }
 
     const { inputState } = this.props;
     const prevInputState = prevProps.inputState;
     if (inputState.draft !== prevInputState.draft) {
       this.updateHeight();
     }
     const curUploadIDs = ChatInputBar.unassignedUploadIDs(
       inputState.pendingUploads,
     );
     const prevUploadIDs = ChatInputBar.unassignedUploadIDs(
       prevInputState.pendingUploads,
     );
     if (
       this.multimediaInput &&
       _difference(prevUploadIDs)(curUploadIDs).length > 0
     ) {
       // Whenever a pending upload is removed, we reset the file
       // HTMLInputElement's value field, so that if the same upload occurs again
       // the onChange call doesn't get filtered
       this.multimediaInput.value = '';
     } else if (
       this.textarea &&
       _difference(curUploadIDs)(prevUploadIDs).length > 0
     ) {
       // Whenever a pending upload is added, we focus the textarea
       this.textarea.focus();
       return;
     }
 
     if (this.props.threadInfo.id !== prevProps.threadInfo.id && this.textarea) {
       this.textarea.focus();
     }
   }
 
   static unassignedUploadIDs(
     pendingUploads: $ReadOnlyArray<PendingMultimediaUpload>,
   ) {
     return pendingUploads
       .filter(
         (pendingUpload: PendingMultimediaUpload) => !pendingUpload.messageID,
       )
       .map((pendingUpload: PendingMultimediaUpload) => pendingUpload.localID);
   }
 
   updateHeight() {
     const textarea = this.textarea;
     if (textarea) {
       textarea.style.height = 'auto';
       const newHeight = Math.min(textarea.scrollHeight, 150);
       textarea.style.height = `${newHeight}px`;
     }
   }
 
   addReplyListener() {
     invariant(
       this.props.inputState,
       'inputState should be set in addReplyListener',
     );
     this.props.inputState.addReplyListener(this.focusAndUpdateText);
   }
 
   removeReplyListener() {
     invariant(
       this.props.inputState,
       'inputState should be set in removeReplyListener',
     );
     this.props.inputState.removeReplyListener(this.focusAndUpdateText);
   }
 
   render() {
     const isMember = viewerIsMember(this.props.threadInfo);
     const canJoin = threadHasPermission(
       this.props.threadInfo,
       threadPermissions.JOIN_THREAD,
     );
 
     let joinButton = null;
     if (!isMember && canJoin && !this.props.threadCreationInProgress) {
       let buttonContent;
       if (this.props.joinThreadLoadingStatus === 'loading') {
         buttonContent = (
           <LoadingIndicator
             status={this.props.joinThreadLoadingStatus}
             size="medium"
             color="white"
           />
         );
       } else {
         buttonContent = (
           <>
             <SWMansionIcon icon="plus" size={24} />
             <p className={css.joinButtonText}>Join Chat</p>
           </>
         );
       }
       joinButton = (
         <div className={css.joinButtonContainer}>
-          <button
+          <Button
+            variant="filled"
+            buttonColor={{ backgroundColor: `#${this.props.threadInfo.color}` }}
             onClick={this.onClickJoin}
-            className={css.joinButton}
-            style={{ backgroundColor: `#${this.props.threadInfo.color}` }}
           >
             {buttonContent}
-          </button>
+          </Button>
         </div>
       );
     }
 
     const { pendingUploads, cancelPendingUpload } = this.props.inputState;
     const multimediaPreviews = pendingUploads.map(pendingUpload => (
       <Multimedia
         uri={pendingUpload.uri}
         pendingUpload={pendingUpload}
         remove={cancelPendingUpload}
         multimediaCSSClass={css.multimedia}
         multimediaImageCSSClass={css.multimediaImage}
         key={pendingUpload.localID}
       />
     ));
     const previews =
       multimediaPreviews.length > 0 ? (
         <div className={css.previews}>{multimediaPreviews}</div>
       ) : null;
 
     let content;
     // If the thread is created by somebody else while the viewer is attempting
     // to create it, the threadInfo might be modified in-place and won't
     // list the viewer as a member, which will end up hiding the input. In
     // this case, we will assume that our creation action will get translated,
     // into a join and as long as members are voiced, we can show the input.
     const defaultMembersAreVoiced = checkIfDefaultMembersAreVoiced(
       this.props.threadInfo,
     );
 
     let sendButton;
     if (this.props.inputState.draft.length) {
       sendButton = (
         <a onClick={this.onSend} className={css.sendButton}>
           <SWMansionIcon
             icon="send-2"
             size={22}
             color={`#${this.props.threadInfo.color}`}
           />
         </a>
       );
     }
 
     if (
       threadHasPermission(this.props.threadInfo, threadPermissions.VOICED) ||
       (this.props.threadCreationInProgress && defaultMembersAreVoiced)
     ) {
       content = (
         <div className={css.inputBarWrapper}>
           <a className={css.multimediaUpload} onClick={this.onMultimediaClick}>
             <input
               type="file"
               onChange={this.onMultimediaFileChange}
               ref={this.multimediaInputRef}
               accept={allowedMimeTypeString}
               multiple
             />
             <SWMansionIcon
               icon="image-1"
               size={22}
               color={`#${this.props.threadInfo.color}`}
               disableFill
             />
           </a>
           <div className={css.inputBarTextInput}>
             <textarea
               rows="1"
               placeholder="Type your message"
               value={this.props.inputState.draft}
               onChange={this.onChangeMessageText}
               onKeyDown={this.onKeyDown}
               ref={this.textareaRef}
               autoFocus
             />
           </div>
           {sendButton}
         </div>
       );
     } else if (
       threadFrozenDueToViewerBlock(
         this.props.threadInfo,
         this.props.viewerID,
         this.props.userInfos,
       ) &&
       threadActualMembers(this.props.threadInfo.members).length === 2
     ) {
       content = (
         <span className={css.explanation}>
           You can&apos;t send messages to a user that you&apos;ve blocked.
         </span>
       );
     } else if (isMember) {
       content = (
         <span className={css.explanation}>
           You don&apos;t have permission to send messages.
         </span>
       );
     } else if (defaultMembersAreVoiced && canJoin) {
       content = null;
     } else {
       content = (
         <span className={css.explanation}>
           You don&apos;t have permission to send messages.
         </span>
       );
     }
 
     return (
       <div className={css.inputBar}>
         {joinButton}
         {previews}
         {content}
       </div>
     );
   }
 
   textareaRef = (textarea: ?HTMLTextAreaElement) => {
     this.textarea = textarea;
     if (textarea) {
       textarea.focus();
     }
   };
 
   onChangeMessageText = (event: SyntheticEvent<HTMLTextAreaElement>) => {
     this.props.inputState.setDraft(event.currentTarget.value);
   };
 
   focusAndUpdateText = (text: string) => {
     // We need to call focus() first on Safari, otherwise the cursor
     // ends up at the start instead of the end for some reason
     const { textarea } = this;
     invariant(textarea, 'textarea should be set');
     textarea.focus();
 
     // We reset the textarea to an empty string at the start so that the cursor
     // always ends up at the end, even if the text doesn't actually change
     textarea.value = '';
     const currentText = this.props.inputState.draft;
     if (!currentText.startsWith(text)) {
       const prependedText = text.concat(currentText);
       this.props.inputState.setDraft(prependedText);
       textarea.value = prependedText;
     } else {
       textarea.value = currentText;
     }
 
     // The above strategies make sure the cursor is at the end,
     // but we also need to make sure that we're scrolled to the bottom
     textarea.scrollTop = textarea.scrollHeight;
   };
 
   onKeyDown = (event: SyntheticKeyboardEvent<HTMLTextAreaElement>) => {
     if (event.keyCode === 13 && !event.shiftKey) {
       event.preventDefault();
       this.send();
     }
   };
 
   onSend = (event: SyntheticEvent<HTMLAnchorElement>) => {
     event.preventDefault();
     this.send();
   };
 
   send() {
     let { nextLocalID } = this.props;
 
     const text = trimMessage(this.props.inputState.draft);
     if (text) {
       // TODO we should make the send button appear dynamically
       // iff trimmed text is nonempty, just like native
       this.dispatchTextMessageAction(text, nextLocalID);
       nextLocalID++;
     }
     if (this.props.inputState.pendingUploads.length > 0) {
       this.props.inputState.createMultimediaMessage(
         nextLocalID,
         this.props.threadInfo,
       );
     }
   }
 
   dispatchTextMessageAction(text: string, nextLocalID: number) {
     this.props.inputState.setDraft('');
 
     const localID = `${localIDPrefix}${nextLocalID}`;
     const creatorID = this.props.viewerID;
     invariant(creatorID, 'should have viewer ID in order to send a message');
 
     this.props.inputState.sendTextMessage(
       {
         type: messageTypes.TEXT,
         localID,
         threadID: this.props.threadInfo.id,
         text,
         creatorID,
         time: Date.now(),
       },
       this.props.threadInfo,
     );
   }
 
   multimediaInputRef = (multimediaInput: ?HTMLInputElement) => {
     this.multimediaInput = multimediaInput;
   };
 
   onMultimediaClick = () => {
     if (this.multimediaInput) {
       this.multimediaInput.click();
     }
   };
 
   onMultimediaFileChange = async (
     event: SyntheticInputEvent<HTMLInputElement>,
   ) => {
     const result = await this.props.inputState.appendFiles([
       ...event.target.files,
     ]);
     if (!result && this.multimediaInput) {
       this.multimediaInput.value = '';
     }
   };
 
-  onClickJoin = (event: SyntheticEvent<HTMLAnchorElement>) => {
-    event.preventDefault();
+  onClickJoin = () => {
     this.props.dispatchActionPromise(joinThreadActionTypes, this.joinAction());
   };
 
   async joinAction() {
     const query = this.props.calendarQuery();
     return await this.props.joinThread({
       threadID: this.props.threadInfo.id,
       calendarQuery: {
         startDate: query.startDate,
         endDate: query.endDate,
         filters: [
           ...query.filters,
           { type: 'threads', threadIDs: [this.props.threadInfo.id] },
         ],
       },
     });
   }
 }
 
 const joinThreadLoadingStatusSelector = createLoadingStatusSelector(
   joinThreadActionTypes,
 );
 const createThreadLoadingStatusSelector = createLoadingStatusSelector(
   newThreadActionTypes,
 );
 
 const ConnectedChatInputBar: React.ComponentType<BaseProps> = React.memo<BaseProps>(
   function ConnectedChatInputBar(props) {
     const viewerID = useSelector(
       state => state.currentUserInfo && state.currentUserInfo.id,
     );
     const nextLocalID = useSelector(state => state.nextLocalID);
     const isThreadActive = useSelector(
       state => props.threadInfo.id === state.navInfo.activeChatThreadID,
     );
     const userInfos = useSelector(state => state.userStore.userInfos);
     const joinThreadLoadingStatus = useSelector(
       joinThreadLoadingStatusSelector,
     );
     const createThreadLoadingStatus = useSelector(
       createThreadLoadingStatusSelector,
     );
     const threadCreationInProgress = createThreadLoadingStatus === 'loading';
     const calendarQuery = useSelector(nonThreadCalendarQuery);
     const dispatchActionPromise = useDispatchActionPromise();
     const callJoinThread = useServerCall(joinThread);
 
     return (
       <ChatInputBar
         {...props}
         viewerID={viewerID}
         joinThreadLoadingStatus={joinThreadLoadingStatus}
         threadCreationInProgress={threadCreationInProgress}
         calendarQuery={calendarQuery}
         nextLocalID={nextLocalID}
         isThreadActive={isThreadActive}
         userInfos={userInfos}
         dispatchActionPromise={dispatchActionPromise}
         joinThread={callJoinThread}
       />
     );
   },
 );
 
 export default ConnectedChatInputBar;