message: Fix: purgable way.
diff: @@ -2,8 +2,8 @@ import classnames from 'classnames';
  import React from 'react';
  type Props = {
  - elevation: number;
  - shadowElevation: number;
  + elevation: 0 | 1 | 2 | 3 | 4 | 5;
  + shadowElevation: 0 | 1 | 2 | 3 | 4 | 5;
  square?: boolean;
  };
  const Paper: React.FC<Props> = ({
  @@ -14,12 +14,23 @@ const Paper: React.FC<Props> = ({
  }) => {
  return (
  <div
  - className={classnames(
  - `text-on-surface bg-surface-0${elevation}dp shadow-0${shadowElevation}dp border border-on-surface-faint`,
  - {
  + className={classnames(`text-on-surface border border-on-surface-faint`, {
  + // Avoid using string concatenation.
  + // @see: https://tailwindcss.com/docs/optimizing-for-production#writing-purgeable-html
  + 'bg-surface-00dp': elevation === 0,
  + 'bg-surface-01dp': elevation === 1,
  + 'bg-surface-02dp': elevation === 2,
  + 'bg-surface-03dp': elevation === 3,
  + 'bg-surface-04dp': elevation === 4,
  + 'bg-surface-05dp': elevation === 5,
  + 'shadow-00dp': shadowElevation === 0,
  + 'shadow-01dp': shadowElevation === 1,
  + 'shadow-02dp': shadowElevation === 2,
  + 'shadow-03dp': shadowElevation === 3,
  + 'shadow-04dp': shadowElevation === 4,
  + 'shadow-05dp': shadowElevation === 5,
  rounded: !square,
  - }
  - )}
  + })}
  >
  {children}
  </div>
  