.mailbox-read .mailmsg-body:not(:has(> .mailmsg-html)) {
  max-width: 72ch;
}

/* A conversation is read before it is filed. Keep the generic record links
   and action tiles available without letting their record-screen treatment
   compete with the message. Native details/summary supplies disclosure state
   and keyboard semantics; the mailbox flow already owns summary activation on
   phone layouts. */
.mailbox-read .mail-related {
  margin: 16px 0 0;
  border-top: 1px solid var(--line);
}
.mailbox-read .mail-related > summary {
  box-sizing: border-box;
  min-height: 44px;
  padding: 12px 4px;
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  color: var(--muted);
  font-size: 13px;
  font-weight: 600;
  line-height: 20px;
  list-style: none;
}
.mailbox-read .mail-related > summary::-webkit-details-marker { display: none; }
.mailbox-read .mail-related > summary::marker { content: ""; }
.mailbox-read .mail-related > summary::before {
  content: "›";
  flex: 0 0 auto;
  font-size: 20px;
  line-height: 1;
  transition: transform 120ms ease;
}
.mailbox-read .mail-related[open] > summary::before { transform: rotate(90deg); }
.mailbox-read .mail-related > summary:hover,
.mailbox-read .mail-related[open] > summary { color: var(--ink); }
.mailbox-read .mail-related > summary:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}
.mailbox-read .mail-related-body { padding: 0 0 8px 20px; }
.mailbox-read .mail-related-body > h2 {
  margin: 4px 0 6px;
  color: var(--muted);
  font-size: 12px;
}
.mailbox-read .mail-related-body > .emptynote:not(.withheldnote) {
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  color: var(--muted);
  font-size: 13px;
}
.mailbox-read .mail-related .allactions {
  margin: 12px 0 0;
  padding: 12px 0 0;
  border-top: 1px solid var(--line);
}
.mailbox-read .mail-related .allactions > h2 {
  margin: 0 0 6px;
  color: var(--muted);
  font-size: 13px;
}
.mailbox-read .mail-related .tiles {
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  margin: 0;
}
.mailbox-read .mail-related .tile {
  min-height: 44px;
  padding: 8px 10px;
}

.mailbox-mobile-nav { display: none; }

.mailbox-check-status { margin: 0; padding: 8px 12px; color: var(--muted); font-size: 13px; }
.mailbox-check-status[hidden] { display: none; }
.mail-conversation-head { display: flex; flex-wrap: wrap; align-items: start; gap: 12px 20px;
  padding-bottom: 18px; margin-bottom: 18px; border-bottom: 1px solid var(--line); }
.mail-conversation-head > .read-title { flex: 1 1 280px; margin: 0; line-height: 1.4;
  font-size: 21px; color: var(--ink); letter-spacing: normal; }
.mail-conversation-head > .next { border: 0; padding: 0; margin: 0; background: none; }
.mail-conversation-head > .next > h2 { position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.mailbox-read .mailmsgs { margin: 0 0 24px; }
.mailbox-read .mailmsg { padding: 20px 0; }
.mailbox-read .mailmsg:first-child { padding-top: 0; }
.mailbox-read .mailmsg[data-state="unread"] { border-left: 0; }
.mailbox-read .mailmsg-body { font-size: 16px; line-height: 1.7; color: var(--ink); }
.mailbox-read .mailmsg-head { margin-bottom: 12px; }
.mailbox-read .mailfacts { margin-top: 20px; }

.mailbox-refresh-note {
  margin: 0 12px 8px;
  padding: 6px 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface-hover);
  color: var(--muted);
  font-size: 13px;
}
.mailbox-refresh-note[hidden] { display: none; }
.mailbox-refresh-note button {
  flex: 0 0 auto;
  min-height: 44px;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--ink);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}
.mailbox-refresh-note button:hover { background: var(--surface-hover); }
.mailbox-refresh-note button:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

@media (min-width: 768px) {
  /* Mailbox choices sit above the working list and message. The office
     navigation already occupies a rail; a second rail squeezed real mail. */
  .mailbox {
    grid-template-columns: minmax(270px, .9fr) minmax(0, 1.6fr);
    grid-template-rows: auto minmax(0, 1fr);
  }
  .mailbox > .mailbox-folders,
  .mailbox.mailbox-wide > .mailbox-folders {
    grid-column: 1 / -1; grid-row: 1;
    display: flex; flex-wrap: wrap; align-items: center; gap: 6px 12px;
    padding: 10px 12px; overflow: visible;
    border-right: 0; border-bottom: 1px solid var(--line);
  }
  .mailbox-folders > .mailbox-compose {
    flex: 0 0 auto; margin: 0; padding: 0; border: 0;
  }
  .mailbox-folders > ul {
    display: flex; flex: 1 1 160px; flex-wrap: wrap; gap: 4px;
    min-width: 0;
  }
  .mailbox-folders .folder { min-width: 120px; min-height: 38px; box-sizing: border-box; }
  .mailbox-folders > .mailbox-check { padding: 0; }
  .mailbox-folders > .mailbox-check button {
    background: transparent; color: var(--ink); border: 1px solid var(--line);
  }
  .mailbox-folders > .mailbox-aux {
    display: flex; flex-direction: row; flex-wrap: wrap; gap: 4px; margin: 0; padding: 0; border: 0;
  }
  .mailbox-folders > .mailbox-aux button { width: auto; min-height: 40px; padding: 8px 10px; }
  .mailbox-folders > .mailbox-keyhint { display: none; }
  .mailbox-folders > :is(.mailbox-note, .mail-receive-status) {
    flex-basis: 100%;
  }
  .mailbox > .mailbox-list { grid-column: 1; grid-row: 2; }
  .mailbox > .mailbox-read { grid-column: 2; grid-row: 2; padding: 20px 24px; }
  .mailbox.mailbox-wide { grid-template-columns: minmax(0, 1fr); }
  .mailbox.mailbox-wide > .mailbox-read {
    grid-column: 1; grid-row: 3; max-height: 60vh;
    border-top: 1px solid var(--line);
  }
  section#pane:has(> #surface-out > .mailbox) { padding: 20px 24px; }
  section#pane:has(> #surface-out > .mailbox) > #surface-out {
    max-width: none;
  }
  /* The flow keeps reader data below a navigation sibling. Preserve the
     established auxiliary-wide empty-reader rule through that wrapper. */
  .mailbox.mailbox-wide .mailbox-read:has(> .mailbox-read-content > .emptynote) {
    display: none;
  }
  /* Preserve the desktop mail-specific treatment of the declared next step. */
  .mailbox-read > .mailbox-read-content > .next {
    border: 0; background: none; padding: 0; margin: 0 0 12px;
  }
  .mailbox-read > .mailbox-read-content > .next > h2 {
    position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0;
    border: 0; overflow: hidden; white-space: nowrap; clip-path: inset(50%);
  }
}

@media (max-width: 767px) {
  .mailbox-refresh-note { flex-wrap: wrap; }
  .mailbox-mobile-nav {
    display: flex;
    position: sticky;
    top: 0;
    z-index: 2;
    margin: -12px -12px 12px;
    padding: 8px 12px;
    background: var(--surface);
    border-bottom: 1px solid var(--line);
  }
  .mailbox-mobile-nav button {
    min-height: 44px;
    padding: 8px 12px;
    border: 1px solid var(--line);
    border-radius: 8px;
    color: var(--ink);
    background: var(--surface);
    font: inherit;
    font-weight: 700;
    cursor: pointer;
  }
  .mailbox-mobile-nav button:hover { background: var(--surface-hover); }
  .mailbox-mobile-nav button:focus-visible {
    outline: 3px solid var(--focus);
    outline-offset: 2px;
  }

  .mailbox > [data-pane] { display: none; }
  .mailbox[data-mail-pane="folders"] > .mailbox-folders,
  .mailbox[data-mail-pane="list"] > .mailbox-list,
  .mailbox[data-mail-pane="read"] > .mailbox-read {
    display: block;
    order: 1;
    max-height: calc(100dvh - var(--tabbar-h) - 24px);
    overflow-y: auto;
  }
}