:root{
  --bg:#f4f7f8;
  --panel:#ffffff;
  --accent:#0d9488;
  --accent-d:#0f766e;
  --accent-soft:#ccfbf1;
  --text:#0f172a;
  --muted:#64748b;
  --border:#e2e8f0;
  --user-grad:linear-gradient(135deg,#0d9488,#14b8a6);
  --shadow:0 1px 3px rgba(15,23,42,.08);
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html,body{margin:0;height:100%;}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--text);
  overscroll-behavior:none;
}
.app{
  display:flex;flex-direction:column;
  height:100dvh;max-width:560px;margin:0 auto;
  background:var(--bg);
}
/* topbar */
.topbar{
  display:flex;align-items:center;justify-content:space-between;
  padding:calc(env(safe-area-inset-top) + 10px) 14px 10px;
  background:var(--panel);border-bottom:1px solid var(--border);
  position:sticky;top:0;z-index:5;
}
.brand{display:flex;align-items:center;gap:10px;}
.logo{font-size:26px;line-height:1;}
.brand-name{font-weight:700;font-size:17px;}
.brand-sub{font-size:11px;color:var(--muted);}
.top-actions{display:flex;align-items:center;gap:8px;}
.chip-toggle{
  border:1px solid var(--border);background:#fff;color:var(--muted);
  font-size:13px;padding:6px 10px;border-radius:999px;cursor:pointer;transition:.15s;
}
.chip-toggle.on{background:var(--accent-soft);color:var(--accent-d);border-color:var(--accent);}
.icon-btn{
  width:34px;height:34px;border-radius:50%;border:none;cursor:pointer;
  background:var(--user-grad);color:#fff;font-size:20px;line-height:1;
  display:flex;align-items:center;justify-content:center;
}
/* messages */
.messages{
  flex:1;overflow-y:auto;padding:16px 12px 8px;
  display:flex;flex-direction:column;gap:14px;
}
.msg{display:flex;gap:8px;align-items:flex-start;max-width:100%;}
.msg.user{flex-direction:row-reverse;}
.avatar{
  width:32px;height:32px;flex:0 0 32px;border-radius:50%;
  background:#e2e8f0;display:flex;align-items:center;justify-content:center;font-size:18px;
}
.msg.user .avatar{background:var(--accent-soft);}
.bubble{
  max-width:78%;background:var(--panel);border:1px solid var(--border);
  border-radius:16px;padding:10px 13px;box-shadow:var(--shadow);
  font-size:15px;line-height:1.65;word-break:break-word;
}
.msg.user .bubble{
  background:var(--user-grad);color:#fff;border:none;border-bottom-right-radius:4px;
}
.msg.assistant .bubble{border-top-left-radius:4px;}
.body{white-space:normal;}
.body br{display:block;content:"";margin:.3em 0;}
.body ul,.body ol{margin:.4em 0;padding-left:1.3em;}
.body li{margin:.2em 0;}
.body code{background:rgba(15,23,42,.06);padding:1px 5px;border-radius:5px;font-size:.92em;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;}
.msg.user .bubble .body code{background:rgba(255,255,255,.22);}
.body pre{background:rgba(15,23,42,.06);padding:10px 12px;border-radius:10px;overflow:auto;margin:.5em 0;}
.body pre code{background:none;padding:0;}
.err{color:#dc2626;font-size:14px;}
.thinking{
  background:rgba(13,148,136,.06);border:1px dashed var(--accent);
  border-radius:12px;padding:6px 10px;margin-bottom:8px;font-size:13px;color:var(--muted);
}
.thinking summary{cursor:pointer;color:var(--accent-d);font-weight:600;outline:none;}
.thinking-body{margin-top:6px;line-height:1.6;}
/* typing */
.typing{display:inline-flex;gap:4px;padding:4px 2px;}
.typing span{width:7px;height:7px;border-radius:50%;background:var(--accent);opacity:.5;animation:blink 1.2s infinite;}
.typing span:nth-child(2){animation-delay:.2s;}
.typing span:nth-child(3){animation-delay:.4s;}
@keyframes blink{0%,80%,100%{opacity:.3;transform:translateY(0);}40%{opacity:1;transform:translateY(-3px);}}
/* suggestions */
.suggest{padding:4px 14px 10px;}
.suggest-title{font-size:12px;color:var(--muted);margin-bottom:8px;}
.platform-title{margin-top:12px;}
.chip-platform{background:#f8fafc;border-color:#cbd5e1;}
.chips{display:flex;flex-wrap:wrap;gap:8px;}
.chip{
  border:1px solid var(--border);background:#fff;color:var(--text);
  font-size:13px;padding:8px 12px;border-radius:14px;cursor:pointer;
  box-shadow:var(--shadow);transition:.15s;
}
.chip:active{transform:scale(.97);}
/* composer */
.composer{
  display:flex;flex-wrap:wrap;align-items:flex-end;gap:8px;padding:10px 12px calc(env(safe-area-inset-bottom) + 10px);
  background:var(--panel);border-top:1px solid var(--border);
}
#input{
  flex:1;resize:none;border:1px solid var(--border);border-radius:18px;
  padding:11px 14px;font-size:15px;line-height:1.4;max-height:140px;
  font-family:inherit;background:#f8fafc;outline:none;
}
#input:focus{border-color:var(--accent);background:#fff;}
.send-btn{
  width:42px;height:42px;flex:0 0 42px;border-radius:50%;border:none;cursor:pointer;
  background:var(--user-grad);color:#fff;font-size:20px;line-height:1;
  display:flex;align-items:center;justify-content:center;
}
.send-btn:disabled{opacity:.5;}

/* ---- 识图：选图按钮 / 预览 / 消息内图片 ---- */
.img-btn{
  width:42px;height:42px;flex:0 0 42px;border-radius:50%;border:1px solid var(--border);
  cursor:pointer;background:#f8fafc;color:var(--accent-d);font-size:19px;line-height:1;
  display:flex;align-items:center;justify-content:center;transition:.15s;
}
.img-btn:active{transform:scale(.94);background:var(--accent-soft);}
.img-btn:disabled{opacity:.5;}
.img-btn svg{display:block;}
.chip-image{border-color:var(--accent);color:var(--accent-d);background:var(--accent-soft);}
.image-preview{
  flex:0 0 100%;display:flex;align-items:center;gap:10px;
  padding:8px 10px;margin-bottom:2px;border:1px dashed var(--accent);
  border-radius:12px;background:rgba(13,148,136,.05);
}
.image-preview[hidden]{display:none;}
.image-preview img{
  width:52px;height:52px;object-fit:cover;border-radius:8px;
  border:1px solid var(--border);background:#fff;flex:0 0 52px;
}
.image-hint{font-size:12px;color:var(--accent-d);flex:1;}
.remove-image{
  width:26px;height:26px;flex:0 0 26px;border:none;border-radius:50%;cursor:pointer;
  background:rgba(15,23,42,.08);color:var(--text);font-size:19px;line-height:1;
  display:flex;align-items:center;justify-content:center;
}
.msg-image{margin:0 0 6px;}
.msg-image img{
  display:block;max-width:100%;max-height:240px;border-radius:10px;cursor:zoom-in;
  object-fit:contain;background:rgba(255,255,255,.15);
}
.msg-image-ph{
  font-size:12px;opacity:.75;margin-bottom:6px;
  border:1px dashed currentColor;border-radius:8px;padding:4px 8px;display:inline-block;
}
.lightbox{
  position:fixed;inset:0;z-index:50;background:rgba(0,0,0,.88);
  display:flex;align-items:center;justify-content:center;padding:16px;cursor:zoom-out;
}
.lightbox[hidden]{display:none;}
.lightbox img{max-width:100%;max-height:100%;object-fit:contain;border-radius:6px;}
.toast{
  position:fixed;left:50%;bottom:88px;transform:translateX(-50%);
  z-index:60;background:rgba(15,23,42,.9);color:#fff;font-size:13px;
  padding:9px 16px;border-radius:999px;max-width:86vw;text-align:center;
  box-shadow:0 4px 16px rgba(0,0,0,.2);pointer-events:none;
}