/* ============================================================
   KATANA Chat — Sample UI
   Design system inherited from ../katana-ui
   Light theme by default; dark theme via [data-theme="dark"]
   ============================================================ */

:root {
  /* Base */
  --bg-primary: #ffffff;
  --bg-secondary: #f7f7f8;
  --bg-tertiary: #ececf1;
  --bg-card: #ffffff;
  --bg-sidebar: #f5f5f7;
  --bg-hover: rgba(0, 128, 128, 0.06);
  --bg-active: rgba(0, 128, 128, 0.12);

  /* Text */
  --text-primary: #1a1a1a;
  --text-secondary: #5a5a6a;
  --text-muted: #8a8a9a;

  /* Border */
  --border-primary: #e2e2e6;
  --border-strong: #d0d0d8;

  /* Accent (KATANA teal) */
  --color-focus: #008080;
  --color-focus-hover: #009999;
  --color-focus-soft: rgba(0, 128, 128, 0.15);

  /* Signal */
  --color-danger: #cc0033;
  --color-warning: #cc8800;
  --color-success: #009944;

  /* Shadow */
  --shadow-card: 0 2px 10px rgba(0, 0, 0, 0.06);
  --shadow-popover: 0 12px 32px rgba(0, 0, 0, 0.12), 0 4px 8px rgba(0, 0, 0, 0.06);
  --shadow-glow: 0 0 15px rgba(0, 128, 128, 0.2);

  /* Font */
  --font-display: 'Orbitron', 'Rajdhani', sans-serif;
  --font-body: 'Noto Sans JP', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Metrics */
  --sidebar-width: 272px;
  --sidebar-collapsed-width: 0px;
  --composer-maxw: min(1440px, 94vw);
  --stream-maxw: min(1440px, 94vw);
  --topbar-h: 48px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
}

[data-theme="dark"] {
  --bg-primary: #0f0f14;
  --bg-secondary: #17171f;
  --bg-tertiary: #1e1e28;
  --bg-card: #17171f;
  --bg-sidebar: #0c0c11;
  --bg-hover: rgba(0, 255, 255, 0.08);
  --bg-active: rgba(0, 255, 255, 0.16);
  --text-primary: #f5f5f7;
  --text-secondary: #a0a0b0;
  --text-muted: #6a6a7a;
  --border-primary: #262633;
  --border-strong: #303040;
  --color-focus: #00e5e5;
  --color-focus-hover: #33ffff;
  --color-focus-soft: rgba(0, 255, 255, 0.15);
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-popover: 0 12px 32px rgba(0, 0, 0, 0.5), 0 4px 8px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(0, 255, 255, 0.2);
}

/* -------- Reset -------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
}
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
input, textarea { font: inherit; color: inherit; }
ul { list-style: none; }
a { color: var(--color-focus); text-decoration: none; }

/* -------- App Shell -------- */
.app {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  height: 100vh;
  min-height: 0;
  transition: grid-template-columns 0.25s ease;
}
.app.app--collapsed {
  grid-template-columns: var(--sidebar-collapsed-width) 1fr;
}

/* ============================================================
   SIDEBAR
   ============================================================ */
.sidebar {
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-primary);
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.app.app--collapsed .sidebar {
  border-right: 0;
  width: 0;
}

.sidebar__top {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 12px 8px;
}
.sidebar__collapse {
  width: 32px;
  height: 32px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
}
.sidebar__collapse:hover { background: var(--bg-hover); color: var(--text-primary); }

.sidebar__brand {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding-left: 4px;
}
.sidebar__logo {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--color-focus);
  letter-spacing: 0.1em;
}
.sidebar__logo-sub {
  font-family: var(--font-display);
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.18em;
}

.sidebar__new {
  margin: 4px 12px 10px;
  padding: 9px 12px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  background: var(--bg-card);
  color: var(--text-primary);
  font-size: 13.5px;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: border-color .15s, background .15s, color .15s;
}
.sidebar__new:hover {
  border-color: var(--color-focus);
  color: var(--color-focus);
  background: var(--bg-hover);
}

.sidebar__search {
  margin: 0 12px 8px;
  padding: 6px 10px;
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  background: var(--bg-primary);
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--text-muted);
}
.sidebar__search:focus-within {
  border-color: var(--color-focus);
  box-shadow: 0 0 0 3px var(--color-focus-soft);
}
.sidebar__search input {
  flex: 1;
  min-width: 0;
  border: 0;
  background: transparent;
  outline: 0;
  color: var(--text-primary);
  font-size: 13px;
}
.sidebar__search input::placeholder { color: var(--text-muted); }
.sidebar__search-clear {
  width: 18px;
  height: 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  border-radius: 4px;
  flex-shrink: 0;
  transition: background .12s, color .12s;
}
.sidebar__search-clear:hover {
  background: rgba(0, 0, 0, 0.06);
  color: var(--text-primary);
}
[data-theme="dark"] .sidebar__search-clear:hover {
  background: rgba(255, 255, 255, 0.08);
}

.sidebar__empty {
  padding: 16px 10px;
  color: var(--text-muted);
  font-size: 12.5px;
  text-align: center;
  line-height: 1.6;
}

.sidebar__history {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  padding: 6px 8px 12px;
}
.sidebar__history::-webkit-scrollbar { width: 6px; }
.sidebar__history::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 3px; }
.sidebar__history::-webkit-scrollbar-track { background: transparent; }

.sidebar__list { padding: 0; }
.sidebar__item {
  position: relative;
  padding: 7px 32px 7px 10px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 13.5px;
  cursor: pointer;
  overflow: hidden;
  transition: background .15s, color .15s;
  margin-bottom: 1px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}
.sidebar__item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}
.sidebar__item--active {
  background: var(--bg-active);
  color: var(--text-primary);
  font-weight: 500;
}
.sidebar__item-title {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  display: block;
}
.sidebar__item-time {
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--text-muted);
  letter-spacing: 0.02em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.sidebar__item--active .sidebar__item-time {
  color: var(--text-secondary);
}
.sidebar__item-title[contenteditable="true"] {
  outline: none;
  background: var(--bg-primary);
  border: 1px solid var(--color-focus);
  border-radius: 4px;
  padding: 1px 4px;
  margin: -2px -4px;
  cursor: text;
}
.sidebar__item-menu {
  position: absolute;
  right: 6px;
  top: 8px;
  width: 22px;
  height: 22px;
  display: none;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  border-radius: 4px;
  transition: background .12s, color .12s;
}
.sidebar__item:hover .sidebar__item-menu,
.sidebar__item--active .sidebar__item-menu,
.sidebar__item-menu[aria-expanded="true"] {
  display: inline-flex;
}
.sidebar__item-menu:hover {
  background: rgba(0, 0, 0, 0.06);
  color: var(--text-primary);
}
[data-theme="dark"] .sidebar__item-menu:hover {
  background: rgba(255, 255, 255, 0.08);
}

/* ============================================================
   USER MENU (bottom left)
   ============================================================ */
.user-menu {
  position: relative;
  border-top: 1px solid var(--border-primary);
  padding: 8px;
  flex-shrink: 0;
}

.user-menu__trigger {
  width: 100%;
  padding: 8px 10px;
  border-radius: var(--radius-md);
  display: grid;
  grid-template-columns: 32px 1fr auto;
  align-items: center;
  gap: 10px;
  text-align: left;
  transition: background .15s;
}
.user-menu__trigger:hover { background: var(--bg-hover); }
.user-menu__trigger[aria-expanded="true"] { background: var(--bg-active); }

.user-menu__avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-focus), #00b3a4);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 12.5px;
  letter-spacing: 0.02em;
  flex-shrink: 0;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.15);
}
.user-menu__avatar--lg {
  width: 40px;
  height: 40px;
  font-size: 15px;
}

.user-menu__meta {
  min-width: 0;
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}
.user-menu__name {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--text-primary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.user-menu__sub {
  font-size: 11px;
  color: var(--text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-family: var(--font-mono);
}
.user-menu__caret {
  color: var(--text-muted);
  transition: transform .2s;
}
.user-menu__trigger[aria-expanded="true"] .user-menu__caret {
  transform: rotate(180deg);
}

/* Popover */
.user-menu__popover {
  position: absolute;
  bottom: calc(100% + 6px);
  left: 8px;
  right: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-popover);
  padding: 6px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: opacity .15s ease, transform .15s ease, visibility .15s;
  z-index: 20;
}
.user-menu__popover[aria-hidden="false"] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.user-menu__popover-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px 10px;
}
.user-menu__popover-meta { min-width: 0; }
.user-menu__popover-name {
  font-weight: 600;
  font-size: 13.5px;
  color: var(--text-primary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.user-menu__popover-mail {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.user-menu__divider {
  height: 1px;
  background: var(--border-primary);
  margin: 4px 2px;
}

.user-menu__list { display: flex; flex-direction: column; gap: 1px; }

.user-menu__item {
  width: 100%;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13.5px;
  color: var(--text-primary);
  text-align: left;
  transition: background .12s;
}
.user-menu__item svg { color: var(--text-secondary); flex-shrink: 0; }
.user-menu__item:hover { background: var(--bg-hover); }
.user-menu__item:hover svg { color: var(--color-focus); }

.user-menu__item--danger { color: var(--color-danger); }
.user-menu__item--danger svg { color: var(--color-danger); }
.user-menu__item--danger:hover {
  background: rgba(204, 0, 51, 0.08);
}
.user-menu__item--danger:hover svg { color: var(--color-danger); }

.user-menu__badge {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--text-muted);
  border: 1px solid var(--border-primary);
  padding: 1px 6px;
  border-radius: 3px;
}

/* ============================================================
   CHAT AREA
   ============================================================ */
.chat {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  background: var(--bg-primary);
}

.chat__topbar {
  height: var(--topbar-h);
  border-bottom: 1px solid var(--border-primary);
  display: flex;
  align-items: center;
  padding: 0 16px;
  gap: 8px;
  flex-shrink: 0;
  background: var(--bg-primary);
}
.chat__topbar-toggle {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  display: none;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.chat__topbar-toggle:hover { background: var(--bg-hover); color: var(--text-primary); }

/* サイドバーが閉じているときだけ、チャット側のトグルを表示 */
.app.app--collapsed .chat__topbar-toggle {
  display: inline-flex;
}

.chat__topbar-title {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: background .15s;
  min-width: 0;
  max-width: 60%;
}
.chat__topbar-title:hover { background: var(--bg-hover); }
.chat__topbar-title[aria-expanded="true"] { background: var(--bg-active); }
.chat__topbar-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.chat__topbar-name[contenteditable="true"] {
  outline: none;
  background: var(--bg-primary);
  border: 1px solid var(--color-focus);
  border-radius: 4px;
  padding: 1px 4px;
  margin: -2px -4px;
  cursor: text;
}
.chat__topbar-spacer { flex: 1; }
.chat__topbar-model {
  font-family: var(--font-mono);
  color: var(--text-muted);
  font-size: 12px;
  letter-spacing: 0.02em;
  padding: 3px 8px;
  border: 1px solid var(--border-primary);
  border-radius: 999px;
}

/* -------- Token Usage Warning (README §11.3: 50/75/80/95%・100%以上) -------- */
.usage-warning {
  padding: 8px 20px;
  font-size: 13px;
  border-bottom: 1px solid var(--border-primary);
}
.usage-warning--info {
  background: var(--bg-secondary);
  color: var(--text-secondary);
}
.usage-warning--warning {
  background: rgba(204, 136, 0, 0.12);
  color: var(--color-warning);
}
.usage-warning--danger {
  background: rgba(204, 0, 51, 0.12);
  color: var(--color-danger);
  font-weight: 500;
}

/* -------- Scrollable Message Stream -------- */
.chat__scroll {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  scroll-behavior: smooth;
}
.chat__scroll::-webkit-scrollbar { width: 10px; }
.chat__scroll::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 5px;
  border: 2px solid var(--bg-primary);
}
.chat__scroll::-webkit-scrollbar-track { background: transparent; }

.chat__stream {
  max-width: var(--stream-maxw);
  width: 100%;
  margin: 0 auto;
  padding: 32px 32px 40px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

/* -------- Messages -------- */
.msg {
  display: grid;
  gap: 12px;
}
.msg--assistant {
  grid-template-columns: 34px 1fr;
}
.msg--user {
  grid-template-columns: 1fr 34px;
}

.msg__avatar {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 12.5px;
  letter-spacing: 0.02em;
}
.msg__avatar--assistant {
  background: linear-gradient(135deg, #0a3d3d, var(--color-focus));
  color: #fff;
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.1) inset;
}
.msg__avatar--user {
  background: linear-gradient(135deg, var(--color-focus), #00b3a4);
  color: #fff;
}
.msg__avatar--thinking {
  animation: avatarPulse 1.4s ease-in-out infinite;
}
@keyframes avatarPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}

.msg__body {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.msg--user .msg__body { align-items: flex-end; }

.msg__meta {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 11.5px;
  color: var(--text-muted);
}
.msg__author {
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 12.5px;
}
.msg__time {
  font-family: var(--font-mono);
  font-size: 11px;
}

.msg__content {
  background: transparent;
  color: var(--text-primary);
  font-size: 15px;
  line-height: 1.75;
  max-width: 100%;
}
.msg--user .msg__content {
  background: var(--bg-active);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: 12px 16px;
  max-width: 76%;
}

.msg__content p { margin: 0 0 0.5em; }
.msg__content p:last-child { margin-bottom: 0; }
.msg__content ul,
.msg__content ol { margin: 0.4em 0 0.6em 1.25em; }
.msg__content li { margin-bottom: 0.15em; }
.msg__content code {
  font-family: var(--font-mono);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-primary);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 0.86em;
  color: var(--color-focus);
}
.msg__content pre {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  margin: 0.6em 0;
}
.msg__content pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 1em;
  color: inherit;
}
.msg__content strong { font-weight: 700; color: var(--text-primary); }
.msg__content h1,
.msg__content h2,
.msg__content h3 {
  margin: 0.8em 0 0.4em;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.4;
}
.msg__content h1 { font-size: 1.25em; }
.msg__content h2 { font-size: 1.15em; }
.msg__content h3 { font-size: 1.05em; }
.msg__content hr {
  border: none;
  border-top: 1px solid var(--border-primary);
  margin: 0.8em 0;
}
.msg__content blockquote {
  margin: 0.4em 0 0.6em;
  padding: 4px 12px;
  border-left: 3px solid var(--border-primary);
  color: var(--text-secondary);
}

.msg__content--thinking {
  font-size: 12.5px;
  color: var(--text-muted);
}

/* Table inside message */
.table-wrap {
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin: 0.6em 0;
  background: var(--bg-card);
}
.table-wrap table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
}
.table-wrap th, .table-wrap td {
  padding: 10px 12px;
  text-align: left;
  border-bottom: 1px solid var(--border-primary);
}
.table-wrap thead th {
  /* bg-secondary はダークモードで bg-card(表の背景)と同色になり見分けがつかないため、
     ライト/ダークどちらでも表の背景とはっきり差が出る bg-tertiary を使う。 */
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 12.5px;
}
.table-wrap tbody tr:last-child td { border-bottom: 0; }
.table-wrap tbody tr:hover { background: var(--bg-hover); }
.td-highlight {
  color: var(--color-focus);
  font-weight: 600;
}
.mono { font-family: var(--font-mono); font-size: 12.5px; color: var(--text-secondary); }

/* Message actions */
.msg__actions {
  display: flex;
  gap: 2px;
  opacity: 0;
  transition: opacity .15s;
}
.msg:hover .msg__actions { opacity: 1; }
.msg__action {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background .12s, color .12s;
}
.msg__action:hover { background: var(--bg-hover); color: var(--color-focus); }

/* ============================================================
   COMPOSER
   ============================================================ */
.composer {
  border-top: 1px solid var(--border-primary);
  background: var(--bg-primary);
  padding: 14px 16px 12px;
  flex-shrink: 0;
}
.composer__inner {
  max-width: var(--composer-maxw);
  width: 100%;
  margin: 0 auto;
}
.composer__form {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: end;
  gap: 6px;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 8px 10px;
  transition: border-color .15s, box-shadow .15s;
}
.composer__form:focus-within {
  border-color: var(--color-focus);
  box-shadow: 0 0 0 3px var(--color-focus-soft);
}

.composer__input {
  width: 100%;
  min-height: 40px;
  max-height: 200px;
  padding: 10px 4px;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text-primary);
  resize: none;
  line-height: 1.55;
  font-size: 15px;
  font-family: var(--font-body);
}
.composer__input::placeholder { color: var(--text-muted); }

.composer__tools {
  display: flex;
  align-items: center;
  gap: 6px;
}

.composer__send {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background: var(--color-focus);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background .15s, transform .1s, box-shadow .15s;
}
.composer__send:hover {
  background: var(--color-focus-hover);
  box-shadow: var(--shadow-glow);
}
.composer__send:active { transform: scale(0.97); }
.composer__send:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  background: var(--text-muted);
  box-shadow: none;
}
.composer__send-icon--stop { display: none; }
.composer__send--stop .composer__send-icon--send { display: none; }
.composer__send--stop .composer__send-icon--stop { display: inline-flex; }
/* 停止ボタンは応答中でも常に押せるため、送信中の disabled 見た目を打ち消す */
.composer__send--stop:disabled {
  opacity: 1;
  cursor: pointer;
  background: var(--color-focus);
}

.composer__disclaimer {
  margin: 8px 4px 0;
  font-size: 11.5px;
  color: var(--text-muted);
  text-align: center;
}
.composer__disclaimer-warning {
  margin-top: 2px;
  color: var(--color-danger);
  font-weight: 600;
}
.composer__disclaimer-warning:not([hidden]) {
  display: block;
}

/* ============================================================
   CONTEXT MENU (rename / delete)
   ============================================================ */
.context-menu {
  position: fixed;
  z-index: 1000;
  min-width: 168px;
  background: var(--bg-card);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-popover);
  padding: 6px;
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.context-menu[hidden] { display: none; }
.context-menu__item {
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13.5px;
  color: var(--text-primary);
  text-align: left;
  width: 100%;
}
.context-menu__item svg { color: var(--text-secondary); flex-shrink: 0; }
.context-menu__item:hover { background: var(--bg-hover); }
.context-menu__item:hover svg { color: var(--color-focus); }
.context-menu__item--danger { color: var(--color-danger); }
.context-menu__item--danger svg { color: var(--color-danger); }
.context-menu__item--danger:hover {
  background: rgba(204, 0, 51, 0.08);
}
.context-menu__item--danger:hover svg { color: var(--color-danger); }

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 900px) {
  :root { --sidebar-width: 260px; }
  .app {
    grid-template-columns: 0 1fr;
  }
  .app:not(.app--mobile-open) .sidebar { display: none; }
  .app:not(.app--mobile-open) .chat__topbar-toggle { display: inline-flex; }
  .chat__stream { padding: 20px 16px 32px; }
  .msg--user .msg__content { max-width: 92%; }
}