content/browser/resources/attribution_reporting/attribution_detail_table.html

<style>
#wrapper, td, th, caption {
  border-color: var(--border-color);
  border-style: solid;
}

#wrapper {
  border-width: 1px;
  max-height: 100%;
  overflow: auto;
}

table {
  border-collapse: separate;
  border-spacing: 0;
  width: 100%;
}

caption {
  background: var(--header-background);
  border-width: 0 0 1px 0;
  position: sticky;
  top: 0;
  z-index: 2;

  div {
    column-gap: 1rem;
    display: inline-flex;
  }
}

caption, td, th {
  font-weight: normal;
  text-align: left;
  vertical-align: top;
}

td {
  border-width: 0 0 1px 0;
}

th {
  background: var(--header-background);
  left: 0;
  position: sticky;
  text-wrap: nowrap;
  z-index: 1;
}

th[scope="row"] {
  border-width: 0 1px 1px 0;
}

tbody.sectioned th[scope="row"] {
  padding-inline-start: calc(1.5 * var(--cell-padding));
}

th[scope="col"] {
  border-width: 0 0 1px 0;
  padding-inline-start: 0;
}

caption div,
th[scope="col"] span {
  left: var(--cell-padding);
  position: sticky;
}

td, th {
  padding-inline: var(--cell-padding);
  text-wrap: nowrap;
}

pre {
  margin: 0;
}
</style>
<div id=wrapper>
  <table>
    <caption>
      <div>
        Details for Selected Row
        <nav>
          <slot name=button></slot>
          <button>Close</button>
        </nav>
      </div>
    </caption>
    <tbody></tbody>
  </table>
</div>