/* ═══════════════════════════════════════════════════════════════
   style.css  —  AI Chat Interface v2
   Aesthetic: refined dark-first, editorial type, geometric accents
   ═══════════════════════════════════════════════════════════════ */

/* ── 1. CSS CUSTOM PROPERTIES ─────────────────────────────────── */

:root {
  /* Layout */
  --sidebar-w:      260px;
  --header-h:       58px;
  --input-bar-h:    90px;

  /* Radii */
  --r-bubble:  18px;
  --r-sm:      8px;
  --r-input:   14px;
  --r-avatar:  50%;

  /* Typography */
  --font-display: 'Syne',    sans-serif;
  --font-body:    'DM Sans', sans-serif;

  /* Motion */
  --ease:       cubic-bezier(.4,0,.2,1);
  --ease-spring:cubic-bezier(.22,1,.36,1);
  --t:          .22s;
}

/* ── DARK theme ── */
[data-theme="dark"] {
  --bg-app:           #0d0e12;
  --bg-sidebar:       #111318;
  --bg-header:        rgba(13,14,18,.85);
  --bg-main:          #0d0e12;
  --bg-input-bar:     #111318;
  --bg-input:         #1a1c25;
  --bg-bubble-ai:     #1a1c25;
  --bg-bubble-user:   #4f6ef7;
  --bg-conv-hover:    rgba(255,255,255,.055);
  --bg-conv-active:   rgba(79,110,247,.14);
  --bg-avatar-user:   #4f6ef7;
  --bg-avatar-ai:     #25273a;
  --border:           rgba(255,255,255,.07);
  --border-input:     rgba(255,255,255,.09);
  --text-primary:     #e4e5f0;
  --text-secondary:   #6b6e87;
  --text-muted:       #3e4057;
  --text-placeholder: #42445a;
  --text-user:        #ffffff;
  --text-ai:          #d0d2e4;
  --accent:           #4f6ef7;
  --accent-hover:     #6a85ff;
  --accent-dim:       rgba(79,110,247,.18);
  --dot:              #555770;
  --kbd-bg:           #22243a;
  --kbd-border:       rgba(255,255,255,.1);
  --copy-hover:       rgba(255,255,255,.08);
  --danger:           #e05c5c;
  --danger-hover:     rgba(224,92,92,.12);
  --logo-mark:        #4f6ef7;
  --code-bg:          #12131a;
  --code-border:      rgba(255,255,255,.06);
  --blockquote-bar:   #4f6ef7;
  --shadow-md:        0 4px 20px rgba(0,0,0,.3);
  --shadow-sm:        0 2px 8px  rgba(0,0,0,.25);
}

/* ── LIGHT theme ── */
[data-theme="light"] {
  --bg-app:           #f0f0f5;
  --bg-sidebar:       #ffffff;
  --bg-header:        rgba(255,255,255,.88);
  --bg-main:          #f0f0f5;
  --bg-input-bar:     #ffffff;
  --bg-input:         #ececf1;
  --bg-bubble-ai:     #ffffff;
  --bg-bubble-user:   #4f6ef7;
  --bg-conv-hover:    rgba(0,0,0,.04);
  --bg-conv-active:   rgba(79,110,247,.1);
  --bg-avatar-user:   #4f6ef7;
  --bg-avatar-ai:     #e8e9f6;
  --border:           rgba(0,0,0,.07);
  --border-input:     rgba(0,0,0,.09);
  --text-primary:     #1a1b28;
  --text-secondary:   #7a7d98;
  --text-muted:       #b0b3cc;
  --text-placeholder: #b5b8d0;
  --text-user:        #ffffff;
  --text-ai:          #1a1b28;
  --accent:           #4f6ef7;
  --accent-hover:     #3a59e8;
  --accent-dim:       rgba(79,110,247,.1);
  --dot:              #aeb1cc;
  --kbd-bg:           #e4e5ef;
  --kbd-border:       rgba(0,0,0,.1);
  --copy-hover:       rgba(0,0,0,.06);
  --danger:           #d94f4f;
  --danger-hover:     rgba(217,79,79,.08);
  --logo-mark:        #4f6ef7;
  --code-bg:          #f5f5fa;
  --code-border:      rgba(0,0,0,.07);
  --blockquote-bar:   #4f6ef7;
  --shadow-md:        0 4px 20px rgba(0,0,0,.1);
  --shadow-sm:        0 2px 8px  rgba(0,0,0,.07);
}

/* ── 2. GLOBAL RESET ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; -webkit-font-smoothing: antialiased; }

body {
  font-family: var(--font-body);
  background: var(--bg-app);
  color: var(--text-primary);
  height: 100dvh;
  overflow: hidden;
  transition: background var(--t) var(--ease), color var(--t) var(--ease);
}

button { font-family: inherit; cursor: pointer; border: none; background: none; }
a      { color: var(--accent); text-underline-offset: 3px; }

/* ── 3. APP SHELL  (sidebar + main side-by-side) ─────────────── */
.app-shell {
  display: flex;
  height: 100dvh;
  overflow: hidden;
}

/* ── 4. SIDEBAR ───────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  transition: background var(--t) var(--ease),
              border-color var(--t) var(--ease),
              transform .3s var(--ease);
  z-index: 200;
  overflow: hidden;
}

/* ── Sidebar header ── */
.sidebar__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 14px 12px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.sidebar__brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Rotating geometric logo mark */
.logo-mark {
  display: block;
  width: 26px; height: 26px;
  border-radius: 7px;
  background: var(--logo-mark);
  position: relative;
  animation: logoSpin 8s linear infinite;
  flex-shrink: 0;
}
.logo-mark::after {
  content: '';
  position: absolute;
  inset: 5px;
  border-radius: 3px;
  background: var(--bg-sidebar);
  transition: background var(--t) var(--ease);
}
@keyframes logoSpin {
  0%,25%  { transform: rotate(0deg);  }
  50%,75% { transform: rotate(45deg); }
  100%    { transform: rotate(90deg); }
}

.sidebar__brand-name {
  font-family: var(--font-display);
  font-size: .9rem;
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--text-primary);
  transition: color var(--t);
}

/* ── Conversation list ── */
.sidebar__nav {
  flex: 1;
  overflow-y: auto;
  padding: 8px 8px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.sidebar__nav::-webkit-scrollbar       { width: 3px; }
.sidebar__nav::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

/* Section label ("Today", "Yesterday") */
.conv-group-label {
  font-size: .65rem;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 10px 8px 4px;
}

/* Individual conversation item */
.conv-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 10px;
  border-radius: var(--r-sm);
  cursor: pointer;
  position: relative;
  transition: background var(--t) var(--ease);
  overflow: hidden;
}
.conv-item:hover              { background: var(--bg-conv-hover); }
.conv-item.active             { background: var(--bg-conv-active); }
.conv-item.active .conv-title { color: var(--accent); }

/* Chat bubble icon in conv item */
.conv-item__icon {
  width: 18px; height: 18px;
  flex-shrink: 0;
  color: var(--text-secondary);
  transition: color var(--t);
}
.conv-item.active .conv-item__icon { color: var(--accent); }

.conv-title {
  flex: 1;
  font-size: .83rem;
  font-weight: 400;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: color var(--t);
}

/* Per-item delete button (appears on hover) */
.conv-delete {
  opacity: 0;
  width: 24px; height: 24px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  flex-shrink: 0;
  transition: opacity .15s, background .15s, color .15s;
}
.conv-item:hover .conv-delete { opacity: 1; }
.conv-delete:hover {
  background: var(--danger-hover);
  color: var(--danger);
}
.conv-delete svg { width: 13px; height: 13px; }

/* ── Sidebar footer (theme toggle) ── */
.sidebar__foot {
  padding: 10px 10px 14px;
  border-top: 1px solid var(--border);
  flex-shrink: 0;
}

.theme-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 10px;
  border-radius: var(--r-sm);
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: .82rem;
  font-weight: 400;
  cursor: pointer;
  transition: background var(--t), border-color var(--t),
              color var(--t), transform .15s;
}
.theme-toggle:hover {
  background: var(--bg-conv-hover);
  color: var(--text-primary);
  border-color: var(--accent);
}
.theme-toggle:active { transform: scale(.97); }

.icon { width: 16px; height: 16px; flex-shrink: 0; }
[data-theme="dark"]  .icon--sun  { display: block; }
[data-theme="dark"]  .icon--moon { display: none;  }
[data-theme="light"] .icon--sun  { display: none;  }
[data-theme="light"] .icon--moon { display: block; }

/* ── 5. SIDEBAR OVERLAY (mobile) ─────────────────────────────── */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.55);
  z-index: 190;
  opacity: 0;
  transition: opacity .3s var(--ease);
}
.sidebar-overlay.active { opacity: 1; }

/* ── 6. MAIN PANEL ────────────────────────────────────────────── */
.main-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--bg-main);
  transition: background var(--t) var(--ease);
  min-width: 0; /* allow flex child to shrink */
}

/* ── 7. HEADER ────────────────────────────────────────────────── */
.header {
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0 20px;
  background: var(--bg-header);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  transition: background var(--t), border-color var(--t);
  z-index: 10;
}

.header__title {
  flex: 1;
  font-family: var(--font-display);
  font-size: .95rem;
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: color var(--t);
}

/* ── 8. ICON BUTTON (shared style) ────────────────────────────── */
.btn-icon {
  width: 34px; height: 34px;
  border-radius: var(--r-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  background: transparent;
  border: none;
  flex-shrink: 0;
  transition: background .15s, color .15s, transform .15s;
}
.btn-icon svg { width: 17px; height: 17px; }
.btn-icon:hover { background: var(--bg-conv-hover); color: var(--text-primary); }
.btn-icon:active { transform: scale(.91); }

.btn-delete:hover { background: var(--danger-hover); color: var(--danger); }
.btn-hamburger { display: none; }   /* visible only on mobile */

/* New-chat button in sidebar head */
#btnNewChat { color: var(--accent); }
#btnNewChat:hover { background: var(--accent-dim); color: var(--accent-hover); }

/* ── 9. CHAT MESSAGES AREA ────────────────────────────────────── */
.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 28px 0 16px;
  display: flex;
  flex-direction: column;
  scroll-behavior: smooth;
}
.chat-messages::-webkit-scrollbar       { width: 4px; }
.chat-messages::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

/* ── 10. MESSAGE ROW ──────────────────────────────────────────── */
/* Full-width row, centred content up to 760px */
.message-row {
  width: 100%;
  padding: 6px 20px;
  display: flex;
  gap: 12px;
  animation: msgIn .38s var(--ease-spring) both;
}

/* AI → left-aligned */
.message-row--ai   { justify-content: flex-start;  align-items: flex-start; }
/* User → right-aligned, reversed */
.message-row--user { justify-content: flex-end;    align-items: flex-start; flex-direction: row-reverse; }

/* Limit inner content width */
.message-row--ai   .msg-body,
.message-row--user .msg-body { max-width: min(680px, 75%); }

/* ── Appear animation ── */
@keyframes msgIn {
  from { opacity: 0; transform: translateY(14px) scale(.97); }
  to   { opacity: 1; transform: translateY(0)    scale(1);   }
}

/* ── 11. AVATAR ───────────────────────────────────────────────── */
.avatar {
  width: 32px; height: 32px;
  border-radius: var(--r-avatar);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .75rem;
  font-weight: 700;
  font-family: var(--font-display);
  letter-spacing: -.01em;
  user-select: none;
  margin-top: 2px;
  /* Subtle pop animation */
  animation: avatarPop .4s var(--ease-spring) both;
}
@keyframes avatarPop {
  from { transform: scale(.7); opacity: 0; }
  to   { transform: scale(1);  opacity: 1; }
}

.avatar--user {
  background: var(--bg-avatar-user);
  color: #fff;
}
.avatar--ai {
  background: var(--bg-avatar-ai);
  color: var(--accent);
  border: 1px solid var(--border);
  /* AI avatar: little sparkle SVG */
}

/* SVG icon inside AI avatar */
.avatar--ai svg { width: 16px; height: 16px; }

/* ── 12. MESSAGE BODY  (label + bubble + timestamp) ───────────── */
.msg-body {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

/* Sender label */
.msg-label {
  font-size: .68rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--text-secondary);
  padding: 0 4px;
}

/* ── 13. BUBBLE ───────────────────────────────────────────────── */
.bubble-wrap {
  position: relative;   /* anchor for copy button */
  display: flex;
  align-items: flex-end;
  gap: 6px;
}

/* Reverse so copy btn sits on outside for user messages */
.message-row--user .bubble-wrap { flex-direction: row-reverse; }

.bubble {
  padding: 11px 15px;
  border-radius: var(--r-bubble);
  font-size: .9rem;
  line-height: 1.65;
  word-break: break-word;
  box-shadow: var(--shadow-sm);
  transition: background var(--t), color var(--t),
              box-shadow var(--t), transform .15s;
  position: relative;
}
/* Subtle lift on hover */
.bubble:hover { box-shadow: var(--shadow-md); transform: translateY(-1px); }

.message-row--ai .bubble {
  background: var(--bg-bubble-ai);
  color: var(--text-ai);
  border: 1px solid var(--border);
  border-bottom-left-radius: 4px;
}
.message-row--user .bubble {
  background: var(--bg-bubble-user);
  color: var(--text-user);
  border-bottom-right-radius: 4px;
}

/* ── 14. COPY BUTTON ──────────────────────────────────────────── */
.copy-btn {
  width: 28px; height: 28px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  background: transparent;
  border: none;
  flex-shrink: 0;
  margin-bottom: 2px;
  /* Hidden until bubble-wrap is hovered */
  opacity: 0;
  transform: scale(.85);
  transition: opacity .15s, transform .15s, background .15s, color .15s;
}
.bubble-wrap:hover .copy-btn {
  opacity: 1;
  transform: scale(1);
}
.copy-btn:hover { background: var(--copy-hover); color: var(--text-primary); }
.copy-btn:active { transform: scale(.88); }
.copy-btn svg { width: 13px; height: 13px; }

/* "Copied!" flash state */
.copy-btn.copied { color: #3ecf8e; }

/* ── 15. TIMESTAMP ─────────────────────────────────────────────── */
.msg-time {
  font-size: .66rem;
  color: var(--text-secondary);
  padding: 0 4px;
  font-style: italic;
  font-weight: 300;
}
.message-row--user .msg-time { text-align: right; }

/* ── 16. DATE DIVIDER ─────────────────────────────────────────── */
.date-divider {
  align-self: center;
  font-size: .67rem;
  font-weight: 600;
  letter-spacing: .07em;
  text-transform: uppercase;
  color: var(--text-secondary);
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 99px;
  padding: 3px 12px;
  margin: 8px 0;
  transition: background var(--t), color var(--t);
}

/* ── 17. MARKDOWN INSIDE BUBBLES ──────────────────────────────── */
/* Scoped to .bubble so prose styles don't leak */

.bubble p        { margin-bottom: .55em; }
.bubble p:last-child { margin-bottom: 0; }
.bubble ul, .bubble ol { padding-left: 1.4em; margin-bottom: .55em; }
.bubble li       { margin-bottom: .2em; }

.bubble h1,.bubble h2,.bubble h3,.bubble h4 {
  font-family: var(--font-display);
  font-weight: 700;
  margin: .6em 0 .3em;
  line-height: 1.25;
}
.bubble h1 { font-size: 1.15em; }
.bubble h2 { font-size: 1.05em; }
.bubble h3 { font-size: .95em; }

/* Inline code */
.bubble code {
  font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  font-size: .82em;
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: 5px;
  padding: 1px 5px;
}

/* Code block */
.bubble pre {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: 10px;
  padding: 12px 14px;
  overflow-x: auto;
  margin: .6em 0;
}
.bubble pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: .8em;
  color: var(--text-primary);
}

/* Blockquote */
.bubble blockquote {
  border-left: 3px solid var(--blockquote-bar);
  padding-left: 12px;
  margin: .5em 0;
  color: var(--text-secondary);
  font-style: italic;
}

/* Table */
.bubble table {
  border-collapse: collapse;
  width: 100%;
  font-size: .85em;
  margin: .6em 0;
}
.bubble th, .bubble td {
  border: 1px solid var(--border);
  padding: 5px 10px;
  text-align: left;
}
.bubble th { font-weight: 600; background: var(--code-bg); }

/* Horizontal rule */
.bubble hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: .7em 0;
}

/* User bubble — invert some elements so they stay readable on blue */
.message-row--user .bubble code {
  background: rgba(255,255,255,.18);
  border-color: rgba(255,255,255,.2);
  color: #fff;
}
.message-row--user .bubble pre {
  background: rgba(0,0,0,.25);
  border-color: rgba(255,255,255,.1);
}
.message-row--user .bubble pre code { color: #d6e0ff; }
.message-row--user .bubble blockquote { color: rgba(255,255,255,.7); border-left-color: rgba(255,255,255,.5); }
.message-row--user .bubble th { background: rgba(0,0,0,.15); }
.message-row--user .bubble th,
.message-row--user .bubble td { border-color: rgba(255,255,255,.2); }

/* Strong / em */
.bubble strong { font-weight: 600; }
.bubble em     { font-style: italic; }
.bubble a      { color: var(--accent); }
.message-row--user .bubble a { color: #c8d9ff; }

/* ── 18. TYPING INDICATOR ─────────────────────────────────────── */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 13px 17px;
  background: var(--bg-bubble-ai);
  border: 1px solid var(--border);
  border-radius: var(--r-bubble);
  border-bottom-left-radius: 4px;
  width: fit-content;
  box-shadow: var(--shadow-sm);
  animation: msgIn .3s var(--ease-spring) both;
}
.typing-indicator span {
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--dot);
  display: block;
  animation: dotBounce 1.3s ease-in-out infinite;
}
.typing-indicator span:nth-child(2) { animation-delay: .16s; }
.typing-indicator span:nth-child(3) { animation-delay: .32s; }

@keyframes dotBounce {
  0%,60%,100% { transform: translateY(0);    opacity: .4; }
  30%          { transform: translateY(-6px); opacity: 1;  }
}

/* ── 19. SCROLL FAB ───────────────────────────────────────────── */
.scroll-fab {
  position: absolute;
  bottom: calc(var(--input-bar-h) + 12px);
  right: 28px;
  width: 36px; height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-bubble-ai);
  color: var(--text-secondary);
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity .2s, transform .2s, background var(--t), color var(--t);
  z-index: 10;
}
.scroll-fab.visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
.scroll-fab:hover   { color: var(--accent); }
.scroll-fab svg     { width: 17px; height: 17px; }

.main-panel { position: relative; } /* anchor FAB */

/* ── 20. INPUT BAR ────────────────────────────────────────────── */
.input-bar {
  background: var(--bg-input-bar);
  border-top: 1px solid var(--border);
  padding: 12px 20px 8px;
  flex-shrink: 0;
  transition: background var(--t), border-color var(--t);
}

.input-bar__inner {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  background: var(--bg-input);
  border: 1px solid var(--border-input);
  border-radius: var(--r-input);
  padding: 9px 9px 9px 15px;
  transition: border-color .2s, box-shadow .2s, background var(--t);
}
.input-bar__inner:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.input-bar__textarea {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  resize: none;
  font-family: var(--font-body);
  font-size: .9rem;
  color: var(--text-primary);
  line-height: 1.55;
  max-height: 160px;
  overflow-y: auto;
  transition: color var(--t);
}
.input-bar__textarea::placeholder { color: var(--text-placeholder); }
.input-bar__textarea::-webkit-scrollbar       { width: 3px; }
.input-bar__textarea::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

.send-btn {
  width: 34px; height: 34px;
  border-radius: 9px;
  border: none;
  background: var(--accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background .2s, transform .15s, opacity .2s;
}
.send-btn svg   { width: 15px; height: 15px; }
.send-btn:hover:not(:disabled)  { background: var(--accent-hover); transform: scale(1.07); }
.send-btn:active:not(:disabled) { transform: scale(.9); }
.send-btn:disabled              { opacity: .3; cursor: not-allowed; }

.input-bar__hint {
  margin-top: 6px;
  font-size: .67rem;
  color: var(--text-secondary);
  text-align: right;
  font-weight: 300;
}
kbd {
  font-family: var(--font-body);
  font-size: .63rem;
  background: var(--kbd-bg);
  border: 1px solid var(--kbd-border);
  border-radius: 4px;
  padding: 1px 5px;
  transition: background var(--t);
}

/* ── 21. EMPTY STATE ──────────────────────────────────────────── */
.empty-state {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 40px 24px;
  text-align: center;
  animation: msgIn .5s var(--ease-spring) both;
}
.empty-state__icon {
  width: 52px; height: 52px;
  border-radius: 14px;
  background: var(--bg-bubble-ai);
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--accent);
}
.empty-state__icon svg { width: 24px; height: 24px; }
.empty-state__title {
  font-family: var(--font-display);
  font-size: 1.1rem; font-weight: 700;
  color: var(--text-primary);
}
.empty-state__sub {
  font-size: .85rem; color: var(--text-secondary);
  max-width: 270px; line-height: 1.6;
}

/* ── 22. RESPONSIVE — MOBILE ──────────────────────────────────── */
@media (max-width: 700px) {
  /* Sidebar slides off-screen by default */
  .sidebar {
    position: fixed;
    top: 0; left: 0; bottom: 0;
    transform: translateX(-100%);
  }
  .sidebar.open      { transform: translateX(0); }
  .sidebar-overlay   { display: block; }
  .btn-hamburger     { display: flex !important; }

  .header { padding: 0 14px; }
  .chat-messages { padding: 16px 0 12px; }
  .message-row   { padding: 5px 12px; }
  .input-bar     { padding: 10px 14px 6px; }
  .input-bar__hint { display: none; }
  .scroll-fab    { right: 14px; }
}

@media (max-width: 480px) {
  .message-row--ai   .msg-body,
  .message-row--user .msg-body { max-width: 90%; }
}