/* ===== BLACK/WHITE DESIGN ===== */
:root {
  --bg: #000000; --sidebar-bg: #0a0a0a; --surface: #111111; --surface-hover: #1a1a1a;
  --border: #222222; --text-primary: #ffffff; --text-secondary: #999; --text-muted: #999;
  --accent: #ffffff; --accent-hover: #e0e0e0; --accent-bg: rgba(255,255,255,0.08);
  --code-bg: #0a0a0a; --code-header-bg: #141414; --code-inline-bg: rgba(255,255,255,0.08);
  --user-bubble-bg: #ffffff; --user-bubble-text: #000000; --scrollbar-thumb: #333;
  --input-bg: #111111; --danger: #ff4444;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --mono: 'JetBrains Mono', 'Consolas', monospace;
}
[data-theme="light"] {
  --bg: #ffffff; --sidebar-bg: #fafafa; --surface: #f5f5f5; --surface-hover: #efefef;
  --border: #e0e0e0; --text-primary: #000000; --text-secondary: #666; --text-muted: #555;
  --accent: #000000; --accent-hover: #333333; --accent-bg: rgba(0,0,0,0.05);
  --code-bg: #f5f5f5; --code-header-bg: #ebebeb; --code-inline-bg: rgba(0,0,0,0.06);
  --user-bubble-bg: #000000; --user-bubble-text: #ffffff; --scrollbar-thumb: #ccc;
  --input-bg: #ffffff; --danger: #cc0000;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html,body,#root{height:100%;overflow:hidden;position:fixed;width:100%}
body{font-family:var(--font);background:var(--bg);color:var(--text-primary);font-size:14px;line-height:1.5}
a{color:var(--text-primary);text-decoration:none}
button{font-family:var(--font);cursor:pointer;border:none;background:none;color:inherit}
::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--scrollbar-thumb);border-radius:3px}

/* ===== LAYOUT ===== */
.app{display:flex;height:100%;height:100dvh}

/* ===== SIDEBAR — NYT editorial ===== */
.sidebar{width:280px;background:var(--sidebar-bg);border-right:1px solid var(--border);display:flex;flex-direction:column;flex-shrink:0;transition:width .2s ease}
.sidebar-header{padding:20px 20px 16px}
.sidebar-header-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px}
.sidebar-logo{display:flex;align-items:center;gap:8px;font-size:17px;font-weight:700;color:var(--text-primary);letter-spacing:-.03em;font-family:var(--font);min-width:0}
.sidebar-logo svg{width:32px;height:32px;opacity:.5;flex-shrink:0}
.sidebar-logo-text{overflow:hidden;white-space:nowrap}
.sidebar-collapse-btn{width:28px;height:28px;border-radius:6px;display:flex;align-items:center;justify-content:center;color:var(--text-muted);transition:all .12s;flex-shrink:0}
.sidebar-collapse-btn:hover{color:var(--text-primary);background:var(--surface-hover)}
.sidebar-collapse-btn svg{width:16px;height:16px}
.new-chat-btn{display:flex;align-items:center;justify-content:center;gap:8px;width:100%;padding:11px 14px;background:transparent;border:1px solid var(--border);border-radius:6px;font-size:13px;font-weight:500;color:var(--text-primary);transition:all .15s;letter-spacing:.01em;overflow:hidden}
.new-chat-btn:hover{border-color:var(--text-primary);background:var(--accent-bg)}
.new-chat-btn svg{opacity:.5;flex-shrink:0}
.new-chat-label{overflow:hidden;white-space:nowrap}
.sidebar-chats{flex:1;overflow-y:auto;padding:8px 12px}
.chat-group-label{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.1em;color:var(--text-muted);padding:20px 8px 8px;border-bottom:1px solid var(--border);margin-bottom:4px;font-family:var(--font);overflow:hidden;white-space:nowrap}
.chat-item{display:flex;align-items:center;padding:10px 8px;font-size:14px;color:var(--text-secondary);cursor:pointer;transition:all .12s;gap:6px;border-bottom:1px solid transparent;border-radius:0;position:relative}
.chat-item:hover{color:var(--text-primary)}
.chat-item::after{content:'';position:absolute;bottom:0;left:8px;right:8px;border-bottom:1px solid var(--border);opacity:.4}
.chat-item:last-child::after{display:none}
.chat-item.active{color:var(--text-primary);font-weight:600}
.chat-item.active::before{content:'';position:absolute;left:0;top:50%;transform:translateY(-50%);width:3px;height:16px;background:var(--text-primary);border-radius:2px}
.chat-item-title{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-family:var(--font);line-height:1.4}
.chat-item-delete{opacity:0;padding:4px 6px;font-size:14px;line-height:1;color:var(--text-muted);border-radius:4px;transition:all .12s;flex-shrink:0}
.chat-item:hover .chat-item-delete{opacity:1}
.chat-item-delete:hover{color:var(--danger)}

/* ===== SIDEBAR BOTTOM ===== */
.sidebar-bottom{border-top:1px solid var(--border);padding:8px 12px}
.settings-trigger{display:flex;align-items:center;gap:8px;width:100%;padding:10px 8px;font-size:13px;color:var(--text-muted);border-radius:0;transition:color .12s;letter-spacing:.01em;overflow:hidden}
.settings-trigger:hover{color:var(--text-primary)}
.settings-trigger svg{width:15px;height:15px;opacity:.6;flex-shrink:0}
.settings-label{overflow:hidden;white-space:nowrap}

/* ===== SIDEBAR COLLAPSED ===== */
.sidebar.collapsed{width:60px}
.sidebar.collapsed .sidebar-header{padding:14px 10px 12px}
.sidebar.collapsed .sidebar-header-top{justify-content:center;margin-bottom:12px}
.sidebar.collapsed .sidebar-logo-text{display:none}
.sidebar.collapsed .sidebar-logo{gap:0}
.sidebar.collapsed .sidebar-logo svg{display:none}
.sidebar.collapsed .sidebar-collapse-btn{width:32px;height:32px}
.sidebar.collapsed .new-chat-btn{padding:10px;gap:0}
.sidebar.collapsed .new-chat-label{display:none}
.sidebar.collapsed .sidebar-chats{padding:8px 6px}
.sidebar.collapsed .chat-group-label{font-size:0;padding:12px 0 4px;border-bottom:1px solid var(--border)}
.sidebar.collapsed .chat-item{padding:8px 0;justify-content:center}
.sidebar.collapsed .chat-item-title{width:24px;flex:none;font-size:0}
.sidebar.collapsed .chat-item-title::first-letter{font-size:14px}
.sidebar.collapsed .chat-item::after{left:4px;right:4px}
.sidebar.collapsed .chat-item.active::before{left:-2px}
.sidebar.collapsed .chat-item-delete{display:none}
.sidebar.collapsed .sidebar-bottom{padding:8px 6px}
.sidebar.collapsed .settings-trigger{justify-content:center;padding:10px 0}
.sidebar.collapsed .settings-label{display:none}

/* ===== SETTINGS POPUP (modal) ===== */
/* ===== SETTINGS POPUP — editorial style ===== */
.settings-overlay{display:none;position:fixed;inset:0;background:rgba(0,0,0,.5);backdrop-filter:blur(4px);-webkit-backdrop-filter:blur(4px);z-index:500;align-items:center;justify-content:center}
.settings-overlay.open{display:flex}
.settings-modal{background:var(--bg);border:1px solid var(--border);border-radius:16px;width:420px;max-width:calc(100vw - 32px);overflow:hidden;box-shadow:0 24px 80px rgba(0,0,0,.4)}
.settings-modal-header{display:flex;align-items:center;justify-content:space-between;padding:20px 24px;border-bottom:1px solid var(--border)}
.settings-modal-header h3{font-size:15px;font-weight:600;letter-spacing:-.01em}
.settings-modal-close{width:32px;height:32px;border-radius:8px;display:flex;align-items:center;justify-content:center;color:var(--text-muted);transition:all .12s}
.settings-modal-close:hover{background:var(--surface-hover);color:var(--text-primary)}
.settings-modal-close svg{width:18px;height:18px}
.settings-modal-body{padding:8px 0}
.settings-item{display:flex;align-items:center;justify-content:space-between;padding:14px 24px;transition:background .1s}
.settings-item:hover{background:var(--surface-hover)}
.settings-item-left{display:flex;align-items:center;gap:12px}
.settings-item-icon{width:36px;height:36px;border-radius:10px;background:var(--surface);border:1px solid var(--border);display:flex;align-items:center;justify-content:center;color:var(--text-secondary);flex-shrink:0}
.settings-item-icon svg{width:18px;height:18px}
.settings-item-label{font-size:13px;font-weight:500;color:var(--text-primary)}
.settings-item-desc{font-size:11px;color:var(--text-muted);margin-top:1px}
.theme-pills{display:flex;gap:2px;background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:2px}
.theme-pill{padding:6px 16px;border-radius:6px;font-size:12px;font-weight:500;color:var(--text-muted);transition:all .12s;border:none}
.theme-pill.active{background:var(--text-primary);color:var(--bg);box-shadow:0 1px 3px rgba(0,0,0,.2)}
.settings-lang-select{appearance:none;-webkit-appearance:none;background:var(--surface);border:1px solid var(--border);border-radius:8px;padding:6px 32px 6px 12px;font-family:var(--font);font-size:12px;font-weight:500;color:var(--text-primary);cursor:pointer;transition:border-color .12s;background-image:url("data:image/svg+xml,%3Csvg width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23999' stroke-width='2.5' xmlns='http://www.w3.org/2000/svg'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 10px center}
.settings-lang-select:hover{border-color:var(--text-muted)}
.settings-lang-select:focus{outline:none;border-color:var(--text-primary)}
.settings-modal-footer{padding:16px 24px;border-top:1px solid var(--border)}
.clear-btn{width:100%;padding:10px;border-radius:10px;font-size:13px;font-weight:500;color:var(--text-secondary);border:1px solid var(--border);transition:all .15s;text-align:center;display:flex;align-items:center;justify-content:center;gap:8px}
.clear-btn svg{width:16px;height:16px}
.clear-btn:hover{border-color:var(--text-muted);color:var(--text-primary);background:var(--surface-hover)}
.clear-btn.confirm{background:var(--danger);color:#fff;border-color:var(--danger)}
.clear-btn.confirm:hover{opacity:.9}

/* ===== CHAT AREA ===== */
.chat-area{flex:1;display:flex;flex-direction:column;min-width:0;min-height:0;overflow:hidden}

/* ===== TOP BAR — models centered ===== */
.top-bar{padding:10px 16px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:center;gap:6px;flex-shrink:0}
.mobile-burger{display:none;padding:6px;border-radius:6px;flex-shrink:0}
.mobile-burger:hover{background:var(--surface-hover)}
.mobile-burger svg{width:20px;height:20px}
.top-bar-inner{position:relative;display:flex;align-items:center;justify-content:center;gap:6px;width:100%}
.model-pills-wrap{display:flex;gap:2px;background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:3px}
.model-pill{display:flex;align-items:center;gap:5px;padding:6px 14px;border-radius:8px;font-size:12px;font-weight:500;white-space:nowrap;border:none;color:var(--text-muted);transition:all .12s;text-decoration:none;cursor:pointer}
.model-pill:hover{color:var(--text-primary);background:var(--surface-hover)}
.model-pill.active{background:var(--text-primary);color:var(--bg);box-shadow:0 1px 3px rgba(0,0,0,.2);cursor:default}
.model-pill .dot{width:6px;height:6px;border-radius:50%;flex-shrink:0}

/* Mobile model dropdown */
.model-dropdown-trigger{display:none;align-items:center;gap:6px;padding:8px 16px;border:1px solid var(--border);border-radius:8px;font-size:13px;font-weight:500;color:var(--text-primary)}
.model-dropdown-trigger .dot{width:6px;height:6px;border-radius:50%}
.model-dropdown-trigger svg{width:12px;height:12px;color:var(--text-muted)}
.model-dropdown{display:none;position:absolute;top:100%;left:50%;transform:translateX(-50%);margin-top:8px;background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:6px;min-width:200px;z-index:50;box-shadow:0 8px 32px rgba(0,0,0,.3)}
.model-dropdown.open{display:block}
.model-dropdown-item{display:flex;align-items:center;gap:8px;padding:8px 12px;border-radius:6px;font-size:13px;color:var(--text-secondary);transition:all .12s;width:100%;text-align:left}
.model-dropdown-item:hover{background:var(--surface-hover);color:var(--text-primary)}
.model-dropdown-item.active{color:var(--text-primary);font-weight:600}
.model-dropdown-item .dot{width:6px;height:6px;border-radius:50%;flex-shrink:0}

/* ===== MESSAGES ===== */
.messages-wrap{flex:1;overflow-y:auto;padding:24px 16px;min-height:0;-webkit-overflow-scrolling:touch}
.messages-col{max-width:760px;margin:0 auto;display:flex;flex-direction:column;gap:24px}
.msg{display:flex;gap:12px}
.msg-user{justify-content:flex-end}
.msg-user .msg-bubble{background:var(--user-bubble-bg);color:var(--user-bubble-text);border-radius:10px 10px 2px 10px;padding:10px 16px;max-width:75%;font-size:14px;line-height:1.6;white-space:pre-wrap}
.msg-user .msg-avatar{width:28px;height:28px;border-radius:50%;background:var(--text-primary);display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:600;color:var(--bg);flex-shrink:0;order:1}
.msg-assistant{align-items:flex-start}
.msg-assistant .msg-content{max-width:100%;position:relative}
.msg-model-label{font-size:11px;font-weight:600;font-family:var(--mono);color:var(--text-muted);margin-bottom:6px;display:flex;align-items:center;gap:6px}
.msg-model-label .dot{width:6px;height:6px;border-radius:50%}
.msg-actions{display:flex;align-items:center;gap:4px;margin-top:8px}
.msg-action-btn{display:inline-flex;align-items:center;gap:5px;padding:4px 10px;border-radius:6px;font-size:12px;font-weight:500;color:var(--text-muted);background:none;border:none;cursor:pointer;transition:all .12s}
.msg-action-btn:hover{color:var(--text-primary);background:var(--surface-hover)}
.typing-dots{display:flex;gap:4px;padding:8px 0}
.typing-dots span{width:6px;height:6px;border-radius:50%;background:var(--text-muted);animation:dotPulse 1.2s ease-in-out infinite}
.typing-dots span:nth-child(2){animation-delay:.2s}
.typing-dots span:nth-child(3){animation-delay:.4s}
@keyframes dotPulse{0%,100%{opacity:.3;transform:scale(.8)}50%{opacity:1;transform:scale(1)}}

/* ===== EMPTY STATE ===== */
.empty-state{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:40px 16px}
.empty-inner{display:flex;flex-direction:column;align-items:center;gap:24px;width:100%;max-width:680px}
.empty-title{font-size:22px;font-weight:600;color:var(--text-primary)}
.empty-input-box{display:flex;align-items:flex-end;gap:10px;background:var(--surface);border:1px solid var(--border);border-radius:20px;padding:16px 18px;width:100%;transition:all .2s;box-shadow:0 2px 12px rgba(0,0,0,.08)}
.empty-input-box:focus-within{border-color:var(--text-muted);box-shadow:0 4px 20px rgba(0,0,0,.12)}
.empty-input-box textarea{flex:1;border:none;background:transparent;resize:none;outline:none;font-family:var(--font);font-size:16px;color:var(--text-primary);line-height:1.6;max-height:160px;min-height:24px;padding:0;display:block}
.empty-input-box textarea::placeholder{color:var(--text-muted)}
.empty-input-box .send-btn{width:30px;height:30px}
.empty-chips{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}
.empty-chip{padding:8px 16px;border:1px solid var(--border);border-radius:20px;font-size:13px;color:var(--text-secondary);transition:all .15s;cursor:pointer;background:none;font-family:var(--font)}
.empty-chip:hover{border-color:var(--text-primary);color:var(--text-primary);background:var(--accent-bg)}

/* ===== INPUT ===== */
.input-area{padding:0 16px 16px;flex-shrink:0}
.input-col{max-width:760px;margin:0 auto}
.input-box{display:flex;align-items:flex-end;gap:10px;background:var(--surface);border:1px solid var(--border);border-radius:16px;padding:14px 16px;transition:all .2s;box-shadow:0 1px 4px rgba(0,0,0,.06)}
.input-box:focus-within{border-color:var(--text-muted);box-shadow:0 2px 12px rgba(0,0,0,.1)}
.input-box textarea{flex:1;border:none;background:transparent;resize:none;outline:none;font-family:var(--font);font-size:16px;color:var(--text-primary);line-height:1.5;max-height:160px;min-height:24px;padding:0;display:block}
.input-box textarea::placeholder{color:var(--text-muted)}
.send-btn{width:30px;height:30px;border-radius:50%;background:var(--text-primary);display:flex;align-items:center;justify-content:center;flex-shrink:0;transition:all .15s;color:var(--bg)}
.send-btn:disabled{opacity:.12;cursor:not-allowed}
.send-btn:not(:disabled):hover{opacity:.8;transform:scale(1.05)}
.send-btn svg{width:16px;height:16px}
.stop-btn{width:36px;height:36px;border-radius:50%;background:var(--danger);display:flex;align-items:center;justify-content:center;flex-shrink:0;color:#fff;transition:all .15s}
.stop-btn:hover{opacity:.85;transform:scale(1.05)}
.stop-btn svg{width:14px;height:14px}
.input-disclaimer{text-align:center;font-size:11px;color:var(--text-muted);margin-top:10px;letter-spacing:.01em}

/* ===== ERROR ===== */
.msg-error{border:1px solid var(--border);border-radius:8px;padding:10px 14px;font-size:13px;color:var(--text-secondary);display:flex;align-items:center;gap:8px}
.msg-error button{padding:4px 10px;border-radius:4px;font-size:12px;font-weight:500;border:1px solid;margin-left:auto;transition:all .12s}
.msg-error button:hover{opacity:.8}

/* ===== PROSE ===== */
.prose{font-size:15px;line-height:1.7;color:var(--text-primary);overflow-wrap:break-word}
.prose h1{font-size:1.4em;font-weight:600;margin:1.2em 0 .6em}.prose h2{font-size:1.2em;font-weight:600;margin:1em 0 .5em}.prose h3{font-size:1.05em;font-weight:600;margin:.8em 0 .4em}
.prose p{margin:.6em 0}.prose ul,.prose ol{padding-left:1.5em;margin:.5em 0}.prose li{margin:.2em 0}
.prose blockquote{border-left:3px solid var(--border);padding-left:1em;color:var(--text-secondary);margin:.8em 0}
.prose table{border-collapse:collapse;width:100%;margin:.8em 0;font-size:.9em}
.prose th,.prose td{border:1px solid var(--border);padding:6px 12px;text-align:left}
.prose th{background:var(--surface);font-weight:500}.prose tr:nth-child(even) td{background:var(--surface)}
.prose code:not(pre code){background:var(--code-inline-bg);padding:1px 6px;border-radius:4px;font-size:.88em;color:var(--text-primary);font-family:var(--mono)}
.prose pre{background:var(--code-bg);border-radius:8px;overflow:hidden;margin:.8em 0}
.prose pre code{display:block;padding:1em;overflow-x:auto;font-size:.88em;line-height:1.6;font-family:var(--mono)}
.code-block-header{display:flex;justify-content:space-between;align-items:center;padding:6px 12px;background:var(--code-header-bg);font-size:12px;color:var(--text-secondary);font-family:var(--mono)}
.code-copy-btn{padding:2px 8px;border-radius:4px;font-size:11px;color:var(--text-muted);cursor:pointer;transition:color .12s}
.code-copy-btn:hover{color:var(--text-primary)}
.katex-display{margin:.8em 0;overflow-x:auto}.katex{font-size:1em}

/* ===== MOBILE ===== */
.sidebar-overlay{display:none;position:fixed;inset:0;background:rgba(0,0,0,.6);z-index:99}
@media(max-width:768px){
  .sidebar{position:fixed;left:0;top:0;bottom:0;z-index:100;transform:translateX(-100%);width:280px}
  .sidebar.collapsed{width:280px}
  .sidebar.open{transform:translateX(0)}
  .sidebar-overlay.open{display:block}
  .sidebar-collapse-btn{display:none}
  .mobile-burger{display:flex;align-items:center}
  .msg-user .msg-bubble{max-width:90%}
  .top-bar{padding:8px 12px}
  .top-bar-inner{justify-content:space-between}
  .model-pills-wrap{display:none}
  .model-dropdown-trigger{display:flex}
  .model-dropdown{left:auto;right:0;transform:none}
}