improved the semantics for our icon scale, fixed preview, fixed navbar desktop

src/App.scss

src/App.vue

src/components/chat_new/chat_new.vue

src/components/extra_buttons/extra_buttons.vue

src/components/favorite_button/favorite_button.vue

src/components/global_notice_list/global_notice_list.vue

src/components/image_cropper/image_cropper.vue

src/components/login_form/login_form.vue

src/components/mfa_form/recovery_form.vue

src/components/mfa_form/totp_form.vue

src/components/mobile_nav/mobile_nav.vue

src/components/nav_panel/nav_panel.vue

src/components/notification/notification.vue

src/components/password_reset/password_reset.vue

src/components/post_status_form/post_status_form.vue

src/components/react_button/react_button.vue

src/components/reply_button/reply_button.vue

src/components/retweet_button/retweet_button.vue

src/components/scope_selector/scope_selector.vue

src/components/search_bar/search_bar.vue