/* Chat and calls. Loaded after components.css; same cascade layer, so the shared
   primitives (.avatar, .btn, .icon-btn, .nav-badge) still apply here. */

@layer components {
  /* ------------------------------------------------------------------ shell */
  /* Three columns: conversation rail, open conversation, details. The details
     column only exists while it is open — [hidden] removes it from the grid. */
  .chat-shell {
    position: relative;
    display: grid;
    grid-template-columns: 320px minmax(0, 1fr);
    block-size: clamp(28rem, calc(100dvh - 14rem), 48rem);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xs);
    overflow: hidden;
  }
  .chat-shell.has-details {
    grid-template-columns: 320px minmax(0, 1fr) 300px;
  }

  /* ------------------------------------------------------------------- rail */
  .chat-rail {
    display: flex;
    flex-direction: column;
    min-block-size: 0;
    background: var(--color-surface);
    border-inline-end: 1px solid var(--color-border);
  }
  .chat-rail__head {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-3) var(--space-3) var(--space-2);
  }
  .chat-rail__title {
    flex: 1;
    font-size: 1.05rem;
    font-weight: 700;
    letter-spacing: -0.02em;
  }
  .chat-rail__tools {
    display: flex;
    gap: 2px;
  }
  .chat-rail__search {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    margin-inline: var(--space-3);
    padding-inline: var(--space-2);
    border: 1px solid transparent;
    border-radius: var(--radius-pill);
    background: var(--color-surface-3);
    color: var(--color-muted);
    transition:
      background-color var(--transition),
      border-color var(--transition),
      box-shadow var(--transition);
  }
  .chat-rail__search input {
    flex: 1;
    min-inline-size: 0;
    padding-block: 0.5rem;
    border: 0;
    background: transparent;
    color: var(--color-text);
    font: inherit;
    font-size: 0.88rem;
  }
  .chat-rail__search input:focus {
    outline: none;
  }
  .chat-rail__search:focus-within {
    background: var(--color-surface);
    border-color: var(--color-primary);
    box-shadow: var(--focus-ring);
  }
  .chat-rail__empty {
    padding: var(--space-3);
    color: var(--color-muted);
    font-size: 0.88rem;
    text-align: center;
  }

  .chat-tabs {
    display: flex;
    gap: var(--space-1);
    padding: var(--space-2) var(--space-3);
  }
  .chat-tab {
    flex: 1;
    padding: 0.35rem 0.5rem;
    border: 0;
    border-radius: var(--radius-pill);
    background: transparent;
    color: var(--color-muted);
    font: inherit;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition:
      background-color var(--transition),
      color var(--transition);
  }
  .chat-tab:hover {
    background: var(--color-surface-3);
    color: var(--color-text);
  }
  .chat-tab.is-active {
    background: var(--color-primary-soft);
    color: var(--color-primary);
  }

  .chat-conv {
    flex: 1;
    min-block-size: 0;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 2px;
    padding: 0 var(--space-2) var(--space-2);
  }
  .chat-conv__item {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    inline-size: 100%;
    padding: 0.6rem var(--space-2);
    border: 0;
    border-radius: var(--radius);
    background: transparent;
    color: var(--color-text);
    font: inherit;
    text-align: start;
    cursor: pointer;
    transition: background-color var(--transition);
  }
  .chat-conv__item:hover {
    background: var(--color-surface-2);
  }
  .chat-conv__item.is-active {
    background: var(--color-primary-soft);
  }
  .chat-conv__body {
    flex: 1;
    min-inline-size: 0;
    display: flex;
    flex-direction: column;
    gap: 1px;
  }
  .chat-conv__top {
    display: flex;
    align-items: baseline;
    gap: var(--space-1);
  }
  .chat-conv__name {
    flex: 1;
    min-inline-size: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.9rem;
    font-weight: 600;
  }
  .chat-conv__time {
    flex: none;
    color: var(--color-muted);
    font-size: 0.7rem;
    font-variant-numeric: tabular-nums;
  }
  .chat-conv__preview {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: var(--color-muted);
    font-size: 0.8rem;
  }
  .chat-conv__item.is-unread .chat-conv__name {
    font-weight: 700;
  }
  .chat-conv__item.is-unread .chat-conv__preview {
    color: var(--color-text);
  }

  /* ------------------------------------------------------------------ panel */
  /* The thread canvas sits a step below --color-surface in both schemes (the page
     background is darker than a card in dark mode and lighter in light mode), so
     bubbles always read as raised above it. */
  .chat-panel {
    position: relative;
    display: flex;
    flex-direction: column;
    min-inline-size: 0;
    min-block-size: 0;
    background: var(--color-bg);
  }
  .chat-head {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    background: var(--color-surface);
    border-block-end: 1px solid var(--color-border);
  }
  .chat-head__back {
    display: none;
  }
  .chat-head__meta {
    flex: 1;
    min-inline-size: 0;
    display: flex;
    flex-direction: column;
    line-height: 1.3;
  }
  .chat-head__title {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.98rem;
    font-weight: 700;
    letter-spacing: -0.01em;
  }
  .chat-head__sub {
    font-size: 0.78rem;
  }
  .chat-head__actions {
    display: flex;
    gap: 2px;
  }

  .chat-blank {
    margin: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-4);
    text-align: center;
  }
  .chat-blank__icon {
    inline-size: 3rem;
    block-size: 3rem;
    color: var(--color-muted);
    opacity: 0.45;
  }
  .chat-blank h3 {
    font-size: 1.1rem;
    font-weight: 700;
  }
  .chat-blank__actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-2);
    margin-block-start: var(--space-1);
  }

  /* ----------------------------------------------------------------- thread */
  .chat-thread {
    flex: 1;
    min-block-size: 0;
    overflow-y: auto;
    overscroll-behavior: contain;
    display: flex;
    flex-direction: column;
    padding: var(--space-3);
  }
  .chat-thread.is-dropping {
    outline: 2px dashed var(--color-primary);
    outline-offset: -10px;
    background: var(--color-primary-soft);
  }
  .chat-thread__intro {
    margin: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-2);
    text-align: center;
  }

  .chat-row {
    display: flex;
    align-items: flex-end;
    gap: var(--space-2);
    max-inline-size: min(78%, 44rem);
  }
  .chat-row + .chat-row {
    margin-block-start: var(--space-2);
  }
  /* Same person, same few minutes: tighten the gap and drop the repeated avatar
     (kept in the layout, just invisible, so the stack stays aligned). */
  .chat-row.is-continued {
    margin-block-start: 2px;
  }
  .chat-row.is-continued .chat-row__avatar {
    visibility: hidden;
  }
  .chat-row--mine {
    align-self: flex-end;
    flex-direction: row-reverse;
  }
  .chat-row__stack {
    display: flex;
    flex-direction: column;
    gap: 2px;
    min-inline-size: 0;
  }
  .chat-row--mine .chat-row__stack {
    align-items: flex-end;
  }
  .chat-row__author {
    padding-inline: 0.25rem;
    color: var(--color-muted);
    font-size: 0.74rem;
    font-weight: 600;
  }

  .chat-bubble {
    display: flex;
    flex-direction: column;
    gap: 1px;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    background: var(--color-surface);
    box-shadow: var(--shadow-xs);
    font-size: 0.92rem;
    overflow-wrap: anywhere;
  }
  .chat-bubble__text {
    white-space: pre-wrap;
  }
  .chat-bubble__time {
    align-self: flex-end;
    color: var(--color-muted);
    font-size: 0.65rem;
    font-variant-numeric: tabular-nums;
    line-height: 1.4;
  }
  /* Squared-off bottom corner on the avatar side reads as the bubble's tail. */
  .chat-row--theirs .chat-bubble {
    border-end-start-radius: 5px;
  }
  .chat-row--mine .chat-bubble {
    border-color: transparent;
    border-end-end-radius: 5px;
    background-image: linear-gradient(
      140deg,
      color-mix(in oklab, var(--color-primary) 90%, white),
      var(--color-primary-strong)
    );
    color: #fff;
    box-shadow: 0 6px 16px -10px color-mix(in oklab, var(--color-primary) 80%, transparent);
  }
  .chat-row--mine .chat-bubble__time {
    color: oklch(100% 0 0 / 0.72);
  }
  .chat-bubble .mention {
    font-weight: 700;
    text-decoration: underline;
    text-underline-offset: 2px;
  }

  .chat-day {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    margin-block: var(--space-3) var(--space-2);
    color: var(--color-muted);
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.07em;
  }
  .chat-day::before,
  .chat-day::after {
    content: "";
    flex: 1;
    border-block-start: 1px solid var(--color-border);
  }
  /* Server-written notice: "… added …", "… left the group". */
  .chat-system {
    align-self: center;
    max-inline-size: 80%;
    margin-block: var(--space-2);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-pill);
    background: var(--color-surface-3);
    color: var(--color-muted);
    font-size: 0.76rem;
    text-align: center;
  }
  .chat-seen {
    align-self: flex-end;
    margin-block-start: 2px;
    color: var(--color-muted);
    font-size: 0.68rem;
    font-weight: 600;
  }

  .chat-attach-img {
    display: block;
    max-inline-size: min(260px, 100%);
    max-block-size: 240px;
    border-radius: var(--radius-sm);
    margin-block-end: 4px;
  }
  .chat-attach-file {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    max-inline-size: 100%;
    padding: 0.35rem 0.6rem;
    margin-block-end: 4px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-surface-2);
    color: var(--color-text);
    font-size: 0.85rem;
    text-decoration: none;
  }
  .chat-attach-file span {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  .chat-attach-file:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    text-decoration: none;
  }
  .chat-row--mine .chat-attach-file {
    background: oklch(100% 0 0 / 0.18);
    border-color: transparent;
    color: #fff;
  }

  /* Typing indicator: three dots that fade in sequence. */
  .chat-typing {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: 0 var(--space-3) var(--space-1);
    color: var(--color-muted);
    font-size: 0.78rem;
  }
  .chat-dots {
    display: inline-flex;
    gap: 3px;
  }
  .chat-dots i {
    inline-size: 5px;
    block-size: 5px;
    border-radius: 50%;
    background: var(--color-primary);
    animation: chat-dot 1.1s ease-in-out infinite;
  }
  .chat-dots i:nth-child(2) {
    animation-delay: 0.15s;
  }
  .chat-dots i:nth-child(3) {
    animation-delay: 0.3s;
  }
  @keyframes chat-dot {
    0%,
    60%,
    100% {
      opacity: 0.25;
      transform: translateY(0);
    }
    30% {
      opacity: 1;
      transform: translateY(-3px);
    }
  }

  /* --------------------------------------------------------------- composer */
  .chat-composer {
    display: flex;
    align-items: flex-end;
    gap: var(--space-1);
    padding: var(--space-2) var(--space-3) var(--space-3);
    background: var(--color-surface);
    border-block-start: 1px solid var(--color-border);
  }
  .chat-composer textarea {
    flex: 1;
    min-inline-size: 0;
    max-block-size: 160px;
    padding: 0.6rem 0.9rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-surface-2);
    color: var(--color-text);
    font: inherit;
    font-size: 0.92rem;
    line-height: 1.45;
    resize: none;
    transition:
      border-color var(--transition),
      box-shadow var(--transition),
      background-color var(--transition);
  }
  .chat-composer textarea:focus-visible {
    outline: none;
    border-color: var(--color-primary);
    background: var(--color-surface);
    box-shadow: var(--focus-ring);
  }
  .chat-send {
    display: inline-grid;
    place-items: center;
    flex: none;
    inline-size: 2.5rem;
    block-size: 2.5rem;
    border: 0;
    border-radius: 50%;
    background-color: var(--color-primary);
    background-image: linear-gradient(
      140deg,
      color-mix(in oklab, var(--color-primary) 88%, white),
      var(--color-primary-strong)
    );
    color: #fff;
    cursor: pointer;
    box-shadow: 0 6px 16px -8px color-mix(in oklab, var(--color-primary) 80%, transparent);
    transition:
      transform 0.08s var(--ease),
      box-shadow var(--transition);
  }
  .chat-send:hover {
    transform: translateY(-1px);
    box-shadow: 0 11px 22px -10px color-mix(in oklab, var(--color-primary) 80%, transparent);
  }
  .chat-send:active {
    transform: translateY(0);
  }

  /* @mention autocomplete, anchored above the composer. */
  .mention-pop {
    position: absolute;
    inset-block-end: 4.6rem;
    inset-inline-start: var(--space-3);
    inline-size: min(320px, calc(100% - 2 * var(--space-3)));
    max-block-size: 240px;
    overflow-y: auto;
    padding: var(--space-1);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    z-index: 30;
  }
  .mention-item {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    inline-size: 100%;
    padding: 0.4rem var(--space-2);
    border: 0;
    border-radius: var(--radius-sm);
    background: none;
    color: var(--color-text);
    font: inherit;
    font-size: 0.88rem;
    text-align: start;
    cursor: pointer;
  }
  .mention-item:hover,
  .mention-item.is-active {
    background: var(--color-surface-2);
  }

  /* ---------------------------------------------------------------- details */
  .chat-details {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    min-block-size: 0;
    overflow-y: auto;
    padding: var(--space-3);
    background: var(--color-surface);
    border-inline-start: 1px solid var(--color-border);
  }
  .chat-details__head {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  .chat-details__head h3 {
    font-size: 0.95rem;
    font-weight: 700;
  }
  .chat-details__hero {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-1);
    text-align: center;
  }
  .chat-details__hero strong {
    font-size: 0.98rem;
  }
  .chat-details__hero .muted {
    font-size: 0.8rem;
  }
  .chat-details__rename {
    display: flex;
    align-items: flex-end;
    gap: var(--space-1);
  }
  .chat-details__rename .field {
    flex: 1;
    margin-block-end: 0;
  }
  .chat-details__section-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-2);
    margin-block-end: var(--space-1);
  }
  .chat-details__section-head h4 {
    color: var(--color-muted);
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.07em;
  }
  .chat-members {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 2px;
  }
  .chat-member {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: 0.3rem;
    border-radius: var(--radius-sm);
  }
  .chat-member:hover {
    background: var(--color-surface-2);
  }
  .chat-member__body {
    flex: 1;
    min-inline-size: 0;
    display: flex;
    flex-direction: column;
    line-height: 1.25;
  }
  .chat-member__name {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.86rem;
    font-weight: 600;
  }
  .chat-member__handle {
    font-size: 0.74rem;
  }

  /* --------------------------------------------------------- people pickers */
  .people-search {
    margin-block-end: var(--space-1);
  }
  .people-list {
    display: flex;
    flex-direction: column;
    gap: 2px;
    max-block-size: 15rem;
    overflow-y: auto;
    margin-block-end: var(--space-2);
  }
  .people-row {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: 0.4rem var(--space-1);
    border-radius: var(--radius-sm);
    cursor: pointer;
  }
  .people-row:hover {
    background: var(--color-surface-2);
  }
  .people-row:has(input:checked) {
    background: var(--color-primary-soft);
  }
  .people-row__body {
    display: flex;
    flex-direction: column;
    min-inline-size: 0;
    line-height: 1.25;
  }
  .people-row__name {
    font-size: 0.88rem;
    font-weight: 600;
  }
  .people-row__meta {
    font-size: 0.74rem;
  }

  /* ------------------------------------------------------------- call dock */
  /* Calls float above the dashboard so the rest of the app stays usable. The
     dock is deliberately dark in both themes: it reads as an overlay, not as
     another panel of the page. */
  .call-dock {
    position: fixed;
    inset-block-end: var(--space-3);
    inset-inline-end: var(--space-3);
    z-index: 150;
    inline-size: min(340px, calc(100vw - 2 * var(--space-3)));
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding-block-end: var(--space-2);
    background: oklch(19% 0.025 265 / 0.92);
    color: oklch(96% 0.01 265);
    border: 1px solid oklch(100% 0 0 / 0.12);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    -webkit-backdrop-filter: blur(14px);
    backdrop-filter: blur(14px);
    animation: call-in 0.22s var(--ease);
  }
  .call-dock__head {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-2) 0;
  }
  .call-dock__dot {
    inline-size: 8px;
    block-size: 8px;
    flex: none;
    border-radius: 50%;
    background: var(--color-success);
    box-shadow: 0 0 0 0 color-mix(in oklab, var(--color-success) 60%, transparent);
    animation: call-live 2s ease-out infinite;
  }
  .call-dock__title {
    flex: 1;
    min-inline-size: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.88rem;
    font-weight: 600;
  }
  .call-dock__timer {
    color: oklch(100% 0 0 / 0.7);
    font-size: 0.76rem;
    font-variant-numeric: tabular-nums;
  }
  .call-dock__collapse {
    display: inline-grid;
    place-items: center;
    inline-size: 1.75rem;
    block-size: 1.75rem;
    border: 0;
    border-radius: var(--radius-sm);
    background: transparent;
    color: oklch(100% 0 0 / 0.7);
    cursor: pointer;
    transition:
      background-color var(--transition),
      transform var(--transition);
  }
  .call-dock__collapse:hover {
    background: oklch(100% 0 0 / 0.12);
    color: #fff;
  }
  .call-dock.is-collapsed .call-dock__collapse {
    transform: rotate(180deg);
  }
  .call-dock.is-collapsed .call-stage {
    display: none;
  }

  .call-stage {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 4px;
    padding-inline: var(--space-2);
  }
  .call-tile {
    position: relative;
    display: grid;
    place-items: center;
    aspect-ratio: 4 / 3;
    overflow: hidden;
    border-radius: var(--radius-sm);
    background: oklch(12% 0.02 265);
  }
  .call-tile video {
    inline-size: 100%;
    block-size: 100%;
    object-fit: cover;
  }
  .call-tile.is-camera-off video {
    visibility: hidden;
  }
  .call-tile__name {
    position: absolute;
    inset-block-end: 4px;
    inset-inline-start: 4px;
    max-inline-size: calc(100% - 8px);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    padding: 1px 6px;
    border-radius: var(--radius-sm);
    background: oklch(0 0 0 / 0.55);
    color: #fff;
    font-size: 0.7rem;
  }
  /* Voice calls show people, not black rectangles. */
  .call-dock[data-mode="audio"] .call-tile {
    aspect-ratio: 3 / 2;
    background: oklch(100% 0 0 / 0.06);
  }

  .call-dock__controls {
    display: flex;
    justify-content: center;
    gap: var(--space-2);
    padding-inline: var(--space-2);
  }
  .call-btn {
    display: inline-grid;
    place-items: center;
    inline-size: 2.5rem;
    block-size: 2.5rem;
    border: 0;
    border-radius: 50%;
    background: oklch(100% 0 0 / 0.14);
    color: #fff;
    cursor: pointer;
    transition:
      background-color var(--transition),
      transform 0.08s var(--ease);
  }
  .call-btn:hover {
    background: oklch(100% 0 0 / 0.24);
    transform: translateY(-1px);
  }
  .call-btn.is-off {
    background: var(--color-danger-bg);
    color: color-mix(in oklab, var(--color-danger) 40%, white);
  }
  .call-btn.is-active {
    background: var(--color-primary);
  }
  .call-btn--end {
    background: var(--color-danger);
  }
  .call-btn--end:hover {
    background: color-mix(in oklab, var(--color-danger) 85%, black);
  }
  .call-btn--accept {
    background: var(--color-success);
  }
  .call-btn--accept:hover {
    background: color-mix(in oklab, var(--color-success) 85%, black);
  }

  /* -------------------------------------------------------------- incoming */
  .call-ring {
    position: fixed;
    /* Clears the sticky topbar, so answering never means clicking over the
       account controls. */
    inset-block-start: 4.75rem;
    inset-inline-end: var(--space-3);
    z-index: 160;
    display: flex;
    align-items: center;
    gap: var(--space-3);
    inline-size: min(360px, calc(100vw - 2 * var(--space-3)));
    padding: var(--space-3);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    animation: call-in 0.25s var(--ease);
  }
  .call-ring__pulse {
    position: relative;
    display: inline-grid;
    place-items: center;
    flex: none;
  }
  .call-ring__pulse::after {
    content: "";
    position: absolute;
    inset: -5px;
    border: 2px solid var(--color-primary);
    border-radius: 50%;
    animation: call-pulse 1.6s ease-out infinite;
  }
  .call-ring__meta {
    flex: 1;
    min-inline-size: 0;
    display: flex;
    flex-direction: column;
    line-height: 1.35;
  }
  .call-ring__meta strong {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  .call-ring__meta .muted {
    font-size: 0.8rem;
  }
  .call-ring__actions {
    display: flex;
    gap: var(--space-1);
  }

  @keyframes call-in {
    from {
      opacity: 0;
      transform: translateY(12px) scale(0.97);
    }
  }
  @keyframes call-pulse {
    to {
      opacity: 0;
      transform: scale(1.5);
    }
  }
  @keyframes call-live {
    70%,
    100% {
      box-shadow: 0 0 0 7px transparent;
    }
  }

  /* ------------------------------------------------------------ responsive */
  /* Not enough width for three columns: the details panel slides over the
     conversation instead of squeezing it. */
  @media (max-width: 1080px) {
    .chat-shell.has-details {
      grid-template-columns: 320px minmax(0, 1fr);
    }
    .chat-details {
      position: absolute;
      inset-block: 0;
      inset-inline-end: 0;
      z-index: 20;
      inline-size: min(300px, 85%);
      box-shadow: var(--shadow);
    }
  }

  /* Phones: one column at a time, the way every messenger does it. The rail is
     the landing view; opening a conversation swaps it for the thread. */
  @media (max-width: 760px) {
    .chat-shell {
      grid-template-columns: minmax(0, 1fr);
      block-size: calc(100dvh - 11rem);
    }
    .chat-shell.has-details,
    .chat-shell.is-open {
      grid-template-columns: minmax(0, 1fr);
    }
    .chat-panel {
      display: none;
    }
    .chat-shell.is-open .chat-rail {
      display: none;
    }
    .chat-shell.is-open .chat-panel {
      display: flex;
    }
    .chat-head__back {
      display: inline-grid;
    }
    .chat-row {
      max-inline-size: 88%;
    }
    .call-dock {
      inline-size: calc(100vw - 2 * var(--space-2));
      inset-inline: var(--space-2);
      inset-block-end: var(--space-2);
    }
    .call-ring {
      inset-inline: var(--space-2);
      inline-size: auto;
    }
  }
}