diff --git a/app/javascript/mastodon/components/callout/callout.stories.tsx b/app/javascript/mastodon/components/callout/callout.stories.tsx
new file mode 100644
index 0000000000..f9bba1ec14
--- /dev/null
+++ b/app/javascript/mastodon/components/callout/callout.stories.tsx
@@ -0,0 +1,93 @@
+import type { Meta, StoryObj } from '@storybook/react-vite';
+import { action } from 'storybook/actions';
+
+import { Callout } from '.';
+
+const meta = {
+  title: 'Components/Callout',
+  args: {
+    children: 'Contents here',
+    title: 'Title',
+    onPrimary: action('Primary action clicked'),
+    primaryLabel: 'Primary',
+    onSecondary: action('Secondary action clicked'),
+    secondaryLabel: 'Secondary',
+    onClose: action('Close clicked'),
+  },
+  component: Callout,
+  render(args) {
+    return (
+      <div style={{ minWidth: 'min(400px, calc(100vw - 2rem))' }}>
+        <Callout {...args} />
+      </div>
+    );
+  },
+} satisfies Meta<typeof Callout>;
+
+export default meta;
+
+type Story = StoryObj<typeof meta>;
+
+export const Default: Story = {
+  args: {
+    variant: 'default',
+  },
+};
+
+export const NoIcon: Story = {
+  args: {
+    icon: false,
+  },
+};
+
+export const NoActions: Story = {
+  args: {
+    onPrimary: undefined,
+    onSecondary: undefined,
+  },
+};
+
+export const OnlyText: Story = {
+  args: {
+    onClose: undefined,
+    onPrimary: undefined,
+    onSecondary: undefined,
+    icon: false,
+  },
+};
+
+// export const Subtle: Story = {
+//   args: {
+//     variant: 'subtle',
+//   },
+// };
+
+export const Feature: Story = {
+  args: {
+    variant: 'feature',
+  },
+};
+
+export const Inverted: Story = {
+  args: {
+    variant: 'inverted',
+  },
+};
+
+export const Success: Story = {
+  args: {
+    variant: 'success',
+  },
+};
+
+export const Warning: Story = {
+  args: {
+    variant: 'warning',
+  },
+};
+
+export const Error: Story = {
+  args: {
+    variant: 'error',
+  },
+};
diff --git a/app/javascript/mastodon/components/callout/dismissible.tsx b/app/javascript/mastodon/components/callout/dismissible.tsx
new file mode 100644
index 0000000000..70a5c850b6
--- /dev/null
+++ b/app/javascript/mastodon/components/callout/dismissible.tsx
@@ -0,0 +1,27 @@
+import { useCallback } from 'react';
+import type { FC } from 'react';
+
+import { useDismissible } from '@/mastodon/hooks/useDismissible';
+
+import { Callout } from '.';
+import type { CalloutProps } from '.';
+
+type DismissibleCalloutProps = CalloutProps & {
+  id: string;
+};
+
+export const DismissibleCallout: FC<DismissibleCalloutProps> = (props) => {
+  const { dismiss, wasDismissed } = useDismissible(props.id);
+
+  const { onClose } = props;
+  const handleClose = useCallback(() => {
+    dismiss();
+    onClose?.();
+  }, [dismiss, onClose]);
+
+  if (wasDismissed) {
+    return null;
+  }
+
+  return <Callout {...props} onClose={handleClose} />;
+};
diff --git a/app/javascript/mastodon/components/callout/index.tsx b/app/javascript/mastodon/components/callout/index.tsx
new file mode 100644
index 0000000000..e7ab410a9c
--- /dev/null
+++ b/app/javascript/mastodon/components/callout/index.tsx
@@ -0,0 +1,150 @@
+import type { FC, ReactNode } from 'react';
+
+import { useIntl } from 'react-intl';
+
+import classNames from 'classnames';
+
+import CheckIcon from '@/material-icons/400-24px/check.svg?react';
+import CloseIcon from '@/material-icons/400-24px/close.svg?react';
+import ErrorIcon from '@/material-icons/400-24px/error.svg?react';
+import InfoIcon from '@/material-icons/400-24px/info.svg?react';
+import WarningIcon from '@/material-icons/400-24px/warning.svg?react';
+
+import type { IconProp } from '../icon';
+import { Icon } from '../icon';
+import { IconButton } from '../icon_button';
+
+import classes from './styles.module.css';
+
+export interface CalloutProps {
+  variant?:
+    | 'default'
+    // | 'subtle'
+    | 'feature'
+    | 'inverted'
+    | 'success'
+    | 'warning'
+    | 'error';
+  title?: ReactNode;
+  children: ReactNode;
+  className?: string;
+  /** Set to false to hide the icon. */
+  icon?: IconProp | boolean;
+  onPrimary?: () => void;
+  primaryLabel?: string;
+  onSecondary?: () => void;
+  secondaryLabel?: string;
+  onClose?: () => void;
+  id?: string;
+}
+
+const variantClasses = {
+  default: classes.variantDefault as string,
+  // subtle: classes.variantSubtle as string,
+  feature: classes.variantFeature as string,
+  inverted: classes.variantInverted as string,
+  success: classes.variantSuccess as string,
+  warning: classes.variantWarning as string,
+  error: classes.variantError as string,
+} as const;
+
+export const Callout: FC<CalloutProps> = ({
+  className,
+  variant = 'default',
+  title,
+  children,
+  icon,
+  onPrimary: primaryAction,
+  primaryLabel,
+  onSecondary: secondaryAction,
+  secondaryLabel,
+  onClose,
+  id,
+}) => {
+  const intl = useIntl();
+
+  return (
+    <aside
+      className={classNames(
+        className,
+        classes.wrapper,
+        variantClasses[variant],
+      )}
+      data-variant={variant}
+      id={id}
+    >
+      <CalloutIcon variant={variant} icon={icon} />
+      <div className={classes.content}>
+        <div className={classes.body}>
+          {title && <h3>{title}</h3>}
+          {children}
+        </div>
+
+        {(primaryAction ?? secondaryAction) && (
+          <div className={classes.actionWrapper}>
+            {secondaryAction && (
+              <button
+                type='button'
+                onClick={secondaryAction}
+                className={classes.action}
+              >
+                {secondaryLabel ?? 'Click'}
+              </button>
+            )}
+
+            {primaryAction && (
+              <button
+                type='button'
+                onClick={primaryAction}
+                className={classes.action}
+              >
+                {primaryLabel ?? 'Click'}
+              </button>
+            )}
+          </div>
+        )}
+      </div>
+
+      {onClose && (
+        <IconButton
+          icon='close'
+          title={intl.formatMessage({
+            id: 'callout.dismiss',
+            defaultMessage: 'Dismiss',
+          })}
+          iconComponent={CloseIcon}
+          className={classes.close}
+          onClick={onClose}
+        />
+      )}
+    </aside>
+  );
+};
+
+const CalloutIcon: FC<Pick<CalloutProps, 'variant' | 'icon'>> = ({
+  variant = 'default',
+  icon,
+}) => {
+  if (icon === false) {
+    return null;
+  }
+
+  if (!icon || icon === true) {
+    switch (variant) {
+      case 'inverted':
+      case 'success':
+        icon = CheckIcon;
+        break;
+      case 'warning':
+        icon = WarningIcon;
+        break;
+      case 'error':
+        icon = ErrorIcon;
+        break;
+      default:
+        icon = InfoIcon;
+    }
+  }
+
+  return <Icon id={variant} icon={icon} className={classes.icon} />;
+};
diff --git a/app/javascript/mastodon/components/callout/styles.module.css b/app/javascript/mastodon/components/callout/styles.module.css
new file mode 100644
index 0000000000..5e6e28d122
--- /dev/null
+++ b/app/javascript/mastodon/components/callout/styles.module.css
@@ -0,0 +1,125 @@
+.wrapper {
+  display: flex;
+  align-items: start;
+  padding: 12px;
+  gap: 8px;
+  background-color: var(--color-bg-brand-softer);
+  color: var(--color-text-primary);
+  border-radius: 12px;
+}
+
+.icon {
+  padding: 4px;
+  border-radius: 9999px;
+  width: 1rem;
+  height: 1rem;
+}
+
+.content {
+  display: flex;
+  gap: 8px;
+  flex-direction: column;
+  flex-grow: 1;
+}
+
+@media screen and (width >= 630px) {
+  .content {
+    flex-direction: row;
+  }
+}
+
+.icon + .content,
+.wrapper:has(.close) .content {
+  margin-top: 2px;
+}
+
+.body {
+  flex-grow: 1;
+
+  h3 {
+    font-weight: 500;
+  }
+}
+
+.actionWrapper {
+  display: flex;
+  gap: 8px;
+  align-items: start;
+}
+
+.action {
+  appearance: none;
+  background: none;
+  border: none;
+  color: inherit;
+  font-weight: 500;
+  padding: 0;
+  text-decoration: underline;
+  transition: color 0.1s ease-in-out;
+
+  &:hover {
+    color: var(--color-text-brand-soft);
+  }
+}
+
+.close {
+  color: inherit;
+
+  svg {
+    width: 20px;
+    height: 20px;
+  }
+}
+
+.variantDefault {
+  .icon {
+    background-color: var(--color-bg-brand-soft);
+  }
+}
+
+/* .variantSubtle {
+  border: 1px solid var(--color-bg-brand-softer);
+  background-color: var(--color-bg-primary);
+
+  .icon {
+    background-color: var(--color-bg-brand-softer);
+  }
+} */
+
+.variantFeature {
+  background-color: var(--color-bg-brand-base);
+  color: var(--color-text-on-brand-base);
+
+  button:hover {
+    color: color-mix(var(--color-text-on-brand-base), transparent 20%);
+  }
+}
+
+.variantInverted {
+  background-color: var(--color-bg-inverted);
+  color: var(--color-text-on-inverted);
+}
+
+.variantSuccess {
+  background-color: var(--color-bg-success-softer);
+
+  .icon {
+    background-color: var(--color-bg-success-soft);
+  }
+}
+
+.variantWarning {
+  background-color: var(--color-bg-warning-softer);
+
+  .icon {
+    background-color: var(--color-bg-warning-soft);
+  }
+}
+
+.variantError {
+  background-color: var(--color-bg-error-softer);
+
+  .icon {
+    background-color: var(--color-bg-error-soft);
+  }
+}
diff --git a/app/javascript/mastodon/locales/en.json b/app/javascript/mastodon/locales/en.json
index 3020e0d34e..72ab261702 100644
--- a/app/javascript/mastodon/locales/en.json
+++ b/app/javascript/mastodon/locales/en.json
@@ -187,6 +187,7 @@
   "bundle_modal_error.close": "Close",
   "bundle_modal_error.message": "Something went wrong while loading this screen.",
   "bundle_modal_error.retry": "Try again",
+  "callout.dismiss": "Dismiss",
   "carousel.current": "<sr>Slide</sr> {current, number} / {max, number}",
   "carousel.slide": "Slide {current, number} of {max, number}",
   "closed_registrations.other_server_instructions": "Since Mastodon is decentralized, you can create an account on another server and still interact with this one.",
diff --git a/app/javascript/material-icons/400-24px/error-fill.svg b/app/javascript/material-icons/400-24px/error-fill.svg
new file mode 100644
index 0000000000..5125e9acce
--- /dev/null
+++ b/app/javascript/material-icons/400-24px/error-fill.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="24" viewBox="0 -960 960 960" width="24"><path d="M480-280q17 0 28.5-11.5T520-320q0-17-11.5-28.5T480-360q-17 0-28.5 11.5T440-320q0 17 11.5 28.5T480-280Zm-40-160h80v-240h-80v240Zm40 360q-83 0-156-31.5T197-197q-54-54-85.5-127T80-480q0-83 31.5-156T197-763q54-54 127-85.5T480-880q83 0 156 31.5T763-763q54 54 85.5 127T880-480q0 83-31.5 156T763-197q-54 54-127 85.5T480-80Z"/></svg>
\ No newline at end of file
diff --git a/app/javascript/material-icons/400-24px/error.svg b/app/javascript/material-icons/400-24px/error.svg
new file mode 100644
index 0000000000..86c4555326
--- /dev/null
+++ b/app/javascript/material-icons/400-24px/error.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="24" viewBox="0 -960 960 960" width="24"><path d="M480-280q17 0 28.5-11.5T520-320q0-17-11.5-28.5T480-360q-17 0-28.5 11.5T440-320q0 17 11.5 28.5T480-280Zm-40-160h80v-240h-80v240Zm40 360q-83 0-156-31.5T197-197q-54-54-85.5-127T80-480q0-83 31.5-156T197-763q54-54 127-85.5T480-880q83 0 156 31.5T763-763q54 54 85.5 127T880-480q0 83-31.5 156T763-197q-54 54-127 85.5T480-80Zm0-80q134 0 227-93t93-227q0-134-93-227t-227-93q-134 0-227 93t-93 227q0 134 93 227t227 93Zm0-320Z"/></svg>
\ No newline at end of file
diff --git a/eslint.config.mjs b/eslint.config.mjs
index a9dc9732bf..c7ba755d67 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -399,6 +399,7 @@ export default tseslint.config([
           allowNumber: true,
         },
       ],
+      '@typescript-eslint/non-nullable-type-assertion-style': 'off',
     },
   },
   {