:root{
  --bg:#f5f5f7; --surface:#ffffff; --surface2:#f0f0f5; --surface3:#e8e8ef;
  --border:rgba(0,0,0,.09); --border-h:rgba(0,0,0,.16);
  --accent:#5b4de0; --accent-glow:rgba(91,77,224,.18); --accent2:#e8805a;
  --green:#16a34a;
  --text-1:#111118; --text-2:#52525e; --text-3:#9090a0;
  --user-bub:#5b4de0; --ai-bub:#f0f0f5;
  --sidebar-w:300px; --header-h:62px;
  --sat:env(safe-area-inset-top,0px);
  --sab:env(safe-area-inset-bottom,0px);
}
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box;-webkit-tap-highlight-color:transparent;touch-action:manipulation;}
html,body{height:100%;overflow:hidden;overscroll-behavior:none;}
body{background:var(--bg);font-family:'DM Sans',sans-serif;color:var(--text-1);display:flex;align-items:stretch;justify-content:center;}
body::before{content:'';position:fixed;inset:0;pointer-events:none;z-index:0;background:radial-gradient(ellipse 55% 45% at 15% 8%,rgba(91,77,224,.06) 0%,transparent 60%),radial-gradient(ellipse 40% 55% at 82% 85%,rgba(232,128,90,.05) 0%,transparent 60%);}

/* App shell */
.app{position:relative;z-index:1;display:flex;width:min(900px,100%);height:100dvh;background:var(--surface);overflow:hidden;}
@media(min-width:861px){.app{border-left:1px solid var(--border);border-right:1px solid var(--border);box-shadow:0 0 40px rgba(0,0,0,.1);}}

/* Overlay */
.overlay{display:none;position:absolute;inset:0;z-index:15;background:rgba(0,0,0,.30);backdrop-filter:blur(3px);-webkit-backdrop-filter:blur(3px);opacity:0;transition:opacity .3s;border-radius:inherit;}
.overlay.show{opacity:1;display:block;}

/* Sidebar */
.sidebar{position:absolute;top:0;left:0;bottom:0;z-index:20;width:var(--sidebar-w);display:flex;flex-direction:column;background:var(--surface);border-right:1px solid var(--border);transform:translateX(-100%);transition:transform .32s cubic-bezier(.16,1,.3,1),box-shadow .32s;overscroll-behavior:contain;}
.sidebar.open{transform:translateX(0);box-shadow:8px 0 40px rgba(0,0,0,.12);}
.sb-header{flex-shrink:0;display:flex;align-items:center;justify-content:space-between;padding:0 18px;padding-top:var(--sat);height:calc(var(--header-h) + var(--sat));border-bottom:1px solid var(--border);gap:10px;}
.sb-brand{display:flex;align-items:center;gap:10px;font-family:'Instrument Serif',serif;font-size:17px;letter-spacing:.01em;}
.sb-logo{width:32px;height:32px;border-radius:10px;background:linear-gradient(135deg,var(--accent),var(--accent2));display:flex;align-items:center;justify-content:center;box-shadow:0 0 12px var(--accent-glow);flex-shrink:0;}
.sb-logo svg{width:15px;height:15px;}
.sb-close{min-width:44px;min-height:44px;border-radius:10px;border:1px solid var(--border);background:transparent;color:var(--text-3);display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background .2s,color .2s;}
.sb-close:hover{background:var(--surface2);color:var(--text-2);}
.sb-close svg{width:16px;height:16px;pointer-events:none;}
.sb-search{flex-shrink:0;padding:12px 14px 8px;}
.search-row{display:flex;align-items:center;gap:8px;background:var(--surface2);border:1px solid var(--border);border-radius:99px;padding:9px 14px;transition:border-color .2s;}
.search-row:focus-within{border-color:rgba(91,77,224,.4);}
.search-row svg{width:14px;height:14px;color:var(--text-3);flex-shrink:0;}
.search-input{flex:1;min-width:0;background:transparent;border:none;outline:none;color:var(--text-1);font-family:'DM Sans',sans-serif;font-size:16px;}
.search-input::placeholder{color:var(--text-3);}
.sb-section{flex-shrink:0;padding:8px 18px 4px;font-size:10px;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--text-3);}
.sb-list{flex:1;min-height:0;overflow-y:auto;padding:4px 8px 12px;display:flex;flex-direction:column;gap:2px;}
.sb-list::-webkit-scrollbar{width:3px;}
.sb-list::-webkit-scrollbar-thumb{background:var(--border);border-radius:99px;}
.hist-item{display:flex;align-items:center;gap:10px;min-height:52px;padding:10px;border-radius:12px;cursor:pointer;transition:background .18s;position:relative;}
.hist-item:hover{background:var(--surface2);}
.hist-item.active{background:rgba(91,77,224,.12);}
.hist-item.active::before{content:'';position:absolute;left:0;top:50%;transform:translateY(-50%);width:3px;height:60%;border-radius:99px;background:var(--accent);}
.hist-icon{width:36px;height:36px;border-radius:10px;display:flex;align-items:center;justify-content:center;flex-shrink:0;font-size:15px;border:1px solid var(--border);background:var(--surface2);}
.hist-info{flex:1;min-width:0;}
.hist-title{font-size:13px;font-weight:500;color:var(--text-1);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
.hist-preview{font-size:12px;color:var(--text-3);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-top:2px;}
.hist-time{font-size:10px;color:var(--text-3);flex-shrink:0;}
.sb-new{flex-shrink:0;padding:10px 14px;border-top:1px solid var(--border);}
.sb-new-btn{width:100%;min-height:48px;padding:12px 0;border-radius:12px;border:1px dashed rgba(91,77,224,.3);background:rgba(91,77,224,.05);color:var(--accent);font-family:'DM Sans',sans-serif;font-size:14px;font-weight:500;display:flex;align-items:center;justify-content:center;gap:7px;cursor:pointer;transition:background .2s,border-color .2s;}
.sb-new-btn:hover{background:rgba(91,77,224,.12);border-color:rgba(91,77,224,.5);}
.sb-new-btn svg{width:15px;height:15px;pointer-events:none;}
.sb-footer{flex-shrink:0;border-top:1px solid var(--border);padding:12px 14px;display:flex;align-items:center;gap:10px;padding-bottom:calc(12px + var(--sab));}
.user-av{width:36px;height:36px;border-radius:50%;background:linear-gradient(135deg,#c7c4f0,#a09bdc);display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:600;color:#fff;flex-shrink:0;border:1px solid var(--border);}
.user-info{flex:1;min-width:0;}
.user-name{font-size:13px;font-weight:500;color:var(--text-1);}
.user-plan{font-size:11px;color:var(--accent);}

/* Chat panel */
.chat-panel{flex:1;min-width:0;display:flex;flex-direction:column;background:var(--surface);}
.chat-header{flex-shrink:0;height:var(--header-h);display:flex;align-items:center;justify-content:space-between;padding:0 16px;border-bottom:1px solid var(--border);background:rgba(255,255,255,.85);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);gap:10px;}
.chat-header-left{display:flex;align-items:center;gap:10px;min-width:0;flex:1;}
.toggle-btn{min-width:44px;min-height:44px;border-radius:10px;border:1px solid var(--border);background:transparent;color:var(--text-2);display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background .2s,color .2s;flex-shrink:0;}
.toggle-btn:hover,.toggle-btn.active{background:var(--surface2);color:var(--text-1);}
.toggle-btn.active{background:rgba(91,77,224,.12);color:var(--accent);border-color:rgba(91,77,224,.3);}
.toggle-btn svg{width:16px;height:16px;pointer-events:none;}
.avatar-ring{width:36px;height:36px;border-radius:50%;background:linear-gradient(135deg,var(--accent),var(--accent2));display:flex;align-items:center;justify-content:center;box-shadow:0 0 12px var(--accent-glow);position:relative;flex-shrink:0;}
.avatar-ring::after{content:'';position:absolute;inset:-2px;border-radius:50%;border:1.5px solid rgba(91,77,224,.4);animation:pulse-ring 2.5s ease-in-out infinite;}
@keyframes pulse-ring{0%,100%{transform:scale(1);opacity:.5}50%{transform:scale(1.12);opacity:0}}
.chat-title{font-family:'Instrument Serif',serif;font-size:15px;letter-spacing:.01em;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
.chat-status{font-size:11px;color:var(--accent);display:flex;align-items:center;gap:5px;margin-top:1px;}
.status-dot{width:5px;height:5px;border-radius:50%;background:var(--green);box-shadow:0 0 6px var(--green);animation:blink 2s ease-in-out infinite;flex-shrink:0;}
@keyframes blink{0%,100%{opacity:1}50%{opacity:.4}}
.chat-header-right{display:flex;gap:4px;flex-shrink:0;}
.icon-btn{min-width:44px;min-height:44px;border-radius:10px;border:1px solid var(--border);background:transparent;color:var(--text-3);display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background .2s,color .2s;}
.icon-btn:hover{background:var(--surface2);color:var(--text-2);}
.icon-btn svg{width:15px;height:15px;pointer-events:none;}

/* Messages */
.messages{flex:1;min-height:0;overflow-y:auto;overflow-x:hidden;-webkit-overflow-scrolling:touch;overscroll-behavior-y:contain;padding:20px 16px;display:flex;flex-direction:column;gap:16px;scroll-behavior:smooth;}
.messages::-webkit-scrollbar{width:3px;}
.messages::-webkit-scrollbar-thumb{background:var(--border);border-radius:99px;}

/* Empty state */
.empty-state{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;animation:fadeIn .7s ease both .2s;padding:0 16px;min-height:60%;}
@keyframes fadeIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.empty-icon{width:54px;height:54px;border-radius:16px;background:linear-gradient(135deg,rgba(91,77,224,.18),rgba(232,128,90,.10));border:1px solid rgba(91,77,224,.2);display:flex;align-items:center;justify-content:center;box-shadow:0 8px 24px rgba(91,77,224,.14);}
.empty-icon svg{width:24px;height:24px;}
.empty-title{font-family:'Instrument Serif',serif;font-size:clamp(19px,5vw,23px);text-align:center;line-height:1.2;}
.empty-title em{font-style:italic;color:var(--accent);}
.empty-sub{font-size:13px;color:var(--text-3);text-align:center;line-height:1.6;max-width:260px;}
.chips{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-top:4px;width:100%;}
.chip{padding:10px 16px;border-radius:99px;border:1px solid var(--border);background:var(--surface2);font-size:13px;color:var(--text-2);cursor:pointer;user-select:none;transition:background .18s,border-color .18s,color .18s;}
.chip:hover,.chip:active{border-color:var(--accent);color:var(--text-1);background:rgba(91,77,224,.08);}

/* Bubbles */
.message-group{display:flex;flex-direction:column;max-width:min(80%,420px);gap:4px;animation:msgIn .3s cubic-bezier(.16,1,.3,1) both;}
@keyframes msgIn{from{opacity:0;transform:translateY(9px)}to{opacity:1;transform:none}}
.message-group.user{align-self:flex-end;align-items:flex-end;}
.message-group.assistant{align-self:flex-start;align-items:flex-start;}
.bubble{padding:11px 15px;border-radius:18px;font-size:14px;line-height:1.65;word-break:break-word;}
.message-group.user .bubble{background:var(--user-bub);border-bottom-right-radius:4px;color:#fff;box-shadow:0 4px 14px rgba(91,77,224,.22);}
.message-group.assistant .bubble{background:var(--ai-bub);border:1px solid var(--border);border-bottom-left-radius:4px;color:var(--text-1);}
.message-group.error .bubble{background:rgba(220,38,38,.06);border:1px solid rgba(220,38,38,.18);color:#dc2626;border-radius:14px;}
.timestamp{font-size:10px;color:var(--text-3);margin-top:2px;padding:0 4px;}
.message-group.user .timestamp{text-align:right;}

/* TTS replay button removed */

/* Typing */
.typing-indicator{display:flex;align-items:center;gap:5px;padding:13px 17px;background:var(--surface2);border:1px solid var(--border);border-radius:18px;border-bottom-left-radius:4px;width:fit-content;align-self:flex-start;}
.typing-dot{width:6px;height:6px;border-radius:50%;background:var(--accent);animation:bounce 1.2s ease-in-out infinite;}
.typing-dot:nth-child(2){animation-delay:.2s;}
.typing-dot:nth-child(3){animation-delay:.4s;}
@keyframes bounce{0%,60%,100%{transform:translateY(0)}30%{transform:translateY(-5px)}}

/* Input area */
.input-area{flex-shrink:0;padding:10px 14px;padding-bottom:calc(10px + var(--sab));border-top:1px solid var(--border);}
.input-row{display:flex;align-items:center;gap:8px;background:var(--surface2);border:1px solid var(--border);border-radius:99px;padding:5px 5px 5px 16px;transition:border-color .2s,box-shadow .2s;}
.input-row:focus-within{border-color:rgba(91,77,224,.45);box-shadow:0 0 0 3px rgba(91,77,224,.07);}
.chat-input{flex:1;min-width:0;background:transparent;border:none;outline:none;color:var(--text-1);font-family:'DM Sans',sans-serif;font-size:16px;caret-color:var(--accent);}
.chat-input::placeholder{color:var(--text-3);}
.mic-btn,.send-btn{width:44px;height:44px;border-radius:50%;flex-shrink:0;display:flex;align-items:center;justify-content:center;cursor:pointer;border:none;transition:transform .2s,box-shadow .2s,background .2s;}
.mic-btn{background:transparent;border:1px solid var(--border);color:var(--text-3);}
.mic-btn:hover{color:var(--accent);border-color:rgba(91,77,224,.4);background:rgba(91,77,224,.05);}
.mic-btn.recording{background:rgba(239,68,68,.12);border-color:rgba(239,68,68,.45);color:#f87171;animation:mic-glow 1s ease-in-out infinite;}
@keyframes mic-glow{0%,100%{box-shadow:0 0 0 0 rgba(239,68,68,0)}50%{box-shadow:0 0 0 8px rgba(239,68,68,.12)}}
.send-btn{background:linear-gradient(135deg,var(--accent),#8b7cf7);color:#fff;box-shadow:0 4px 12px rgba(91,77,224,.28);}
.send-btn:hover:not(:disabled){transform:scale(1.06);box-shadow:0 6px 20px rgba(91,77,224,.40);}
.send-btn:active:not(:disabled){transform:scale(.93);}
.send-btn:disabled{background:var(--surface3);box-shadow:none;color:var(--text-3);cursor:not-allowed;}
.mic-btn svg,.send-btn svg{width:16px;height:16px;pointer-events:none;}
.send-btn svg{margin-left:1px;}
.input-hint{font-size:11px;color:var(--text-3);text-align:center;margin-top:8px;}
.input-hint kbd{background:var(--surface3);border:1px solid var(--border);border-radius:4px;padding:1px 5px;font-size:10px;font-family:inherit;}
@media(pointer:coarse){.input-hint{display:none}}

/* Mobile */
@media(max-width:600px){
  .chat-header{padding-top:var(--sat);height:calc(var(--header-h) + var(--sat));}
  .sidebar{width:min(300px,85vw);}
  .message-group{max-width:88%;}
}