.screen { min-height: 100vh; }

#screen-chat {
  min-height: 100vh;
  background:
    linear-gradient(rgba(26, 25, 22, 0.025) 1px, transparent 1px) 0 0 / 100% 2rem,
    var(--color-paper);
}

#sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  width: var(--sidebar-width);
  display: flex;
  flex-direction: column;
  background: color-mix(in srgb, var(--color-paper) 92%, var(--color-paper-sunken));
  border-right: var(--border-thin);
  z-index: 50;
}

.sidebar-header,
.sidebar-footer {
  padding: var(--space-4);
}

.sidebar-list {
  flex: 1;
  overflow-y: auto;
  padding: 0 var(--space-3) var(--space-4);
}

.sidebar-footer {
  color: var(--color-ink-muted);
  border-top: var(--border-thin);
}

.sidebar-handle { display: none; }

#chat-main {
  min-height: 100vh;
  margin-left: var(--sidebar-width);
  display: flex;
  flex-direction: column;
}

#chat-topbar {
  height: 64px;
  display: grid;
  grid-template-columns: 44px 1fr auto;
  align-items: center;
  gap: var(--space-3);
  padding: 0 var(--space-4);
  border-bottom: var(--border-thin);
  background: color-mix(in srgb, var(--color-paper) 88%, transparent);
  position: sticky;
  top: 0;
  z-index: 20;
}

#conversation-title {
  font-size: var(--text-base);
  font-weight: var(--weight-medium);
  line-height: var(--leading-tight);
  text-align: center;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#conversation-title[contenteditable="true"] {
  outline: 2px solid var(--color-accent);
  background: var(--color-paper-raised);
  border-radius: var(--radius-sm);
  padding: var(--space-1) var(--space-2);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

#chat-input-area {
  position: sticky;
  bottom: 0;
  z-index: 30;
  padding: var(--space-3) var(--space-4) var(--space-4);
  background: linear-gradient(transparent, var(--color-paper) 18%);
}

#chat-input-area > * {
  max-width: var(--chat-max-width);
  margin-left: auto;
  margin-right: auto;
}

.mobile-only { display: none; }

#profile-panel {
  position: fixed;
  inset: 0 0 0 auto;
  width: 320px;
  display: flex;
  flex-direction: column;
  background: var(--color-paper-raised);
  border-left: var(--border-thin);
  box-shadow: var(--shadow-md);
  z-index: 180;
}

.panel-header,
.panel-section,
.panel-footer {
  padding: var(--space-5);
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: var(--border-thin);
}

.panel-section + .panel-section,
.panel-footer {
  border-top: var(--border-thin);
}

.panel-footer { margin-top: auto; }

#sidebar-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.28);
  z-index: 40;
}

@media (max-width: 767px) {
  #sidebar {
    inset: auto 0 0 0;
    width: auto;
    height: 75vh;
    border-right: 0;
    border-top: var(--border-thin);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    transform: translateY(100%);
    transition: transform 300ms cubic-bezier(0.32, 0.72, 0, 1);
    z-index: 200;
  }

  #sidebar.is-open { transform: translateY(0); }

  .sidebar-handle {
    display: block;
    width: 48px;
    height: 4px;
    margin: var(--space-3) auto var(--space-1);
    border-radius: var(--radius-full);
    background: var(--color-ink-faint);
  }

  #chat-main { margin-left: 0; }

  .mobile-only { display: inline-flex; }

  #chat-topbar {
    grid-template-columns: 44px 1fr auto;
  }

  #profile-panel {
    inset: auto 0 0 0;
    width: auto;
    max-height: 92vh;
    border-left: 0;
    border-top: var(--border-thin);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  }
}