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                <form class="grid">
  <h1>Secure Checkout</h1>
  <div class="warning card">Warning stuff</div>
  <fieldset class="card">
    <h3>Your details</h3>
    <label for="name">First Name</label>
    <input type="text" id="name" />
  <fieldset class="card">
    <h3>Other stuff</h3>
    <label for="thing">Thing</label>
    <input type="text" id="thing" />
  <div class="sidebar">
    <div class="card">
      <h3>The sidebar</h3>
      <p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Architecto, nulla.</p>
      <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Rerum, fuga. Consectetur pariatur quidem veniam illum cum. Expedita voluptate quibusdam sed nobis, ut quod ipsum nostrum ducimus dolores commodi et sequi recusandae ad, accusamus minus, perspiciatis corrupti modi reiciendis suscipit. Et qui, fugit iusto consequuntur repellat nihil saepe quos exercitationem ducimus dolorem, laudantium porro odit. Tempore, natus totam praesentium rem excepturi reiciendis soluta ipsa minus deserunt nostrum voluptas, sequi voluptates cupiditate dolores laudantium officia, atque repellat suscipit saepe voluptatibus molestias maiores non! Voluptatem cupiditate totam deleniti dicta doloribus quibusdam. Laudantium aperiam explicabo assumenda eius voluptate quia fugiat possimus eum cupiditate eaque!</p>
  <button type="submit">Submit</button>


                .grid {
  margin: 2rem auto;
  height: 100%;
  & > * + * {
    margin-top: 1rem;
  @media(min-width: 40em) {
    max-width: 60rem;
    margin: 4rem auto;
    display: grid;
    align-content: start;
    grid-template-columns: 1fr 20rem;
    column-gap: 2rem;
    & > * {
      grid-column: 1;

.card {
  padding: 1rem;
  border: 1px solid grey;

.sidebar {
  @media(min-width: 40em) {
    margin-top: 0;
    grid-column: 2;
    grid-row: 1 / 100;
    position: sticky;
    top: 1rem;

.warning {
  background-color: skyblue;

* {
  margin: 0;
  box-sizing: border-box;

body {
  height: 150vh;

h1 {
  margin: 0;

button {
  display: block;
  width: 100%;
  background: none;
  border: 1px solid;
  font-family: inherit;
  font-size: inherit;
  padding: 0.5rem;

fieldset {
  border: 0;
  padding: 0;
  margin: 0;