:root{
  --bg:#121015;--bg2:#0b0a0d;--panel:rgba(255,255,255,.06);
  --border:rgba(255,255,255,.08);--text:#e5e7eb;--muted:#8b8b93;
  --accent:#34d399;--accent-2:#efbf5a;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;color:var(--text);
  background: radial-gradient(60% 80% at 50% 0%, #2A1E33 0%, #121015 55%, #0b0a0d 100%);
  font:14px/1.5 ui-sans-serif,system-ui,Segoe UI,Roboto,Helvetica,Arial;
}

/* 顶栏 */
.topbar{
  position:sticky;top:0;z-index:10;
  display:flex;align-items:center;justify-content:space-between;
  height:56px;padding:0 16px;border-bottom:1px solid var(--border);
  backdrop-filter:saturate(1.4) blur(8px);background:rgba(0,0,0,.35);
}
.brand{display:flex;align-items:center;gap:8px;font-weight:600}
.logo{width:40px;height:40px;border-radius:10px;background-image:url('./robot.png');background-size:cover;background-position:center;background-repeat:no-repeat}
.toolbar{display:flex;align-items:center;gap:8px}

/* 提升模型下拉可读性：深色背景 + 高亮文字 + 绿色描边 */
.select{
  appearance:none;
  background:#0f172a; /* 与页面背景拉开对比 */
  border:1px solid #34d39966;
  color:#e2e8f0;
  font-weight:700;
  padding:8px 12px;
  border-radius:10px;
  transition:border-color .2s, box-shadow .2s, background .2s;
}
.select:hover{border-color:#34d39999}
.select:focus{outline:0;border-color:#34d399;box-shadow:0 0 0 3px rgba(52,211,153,.25)}
.select option{background:#0f172a;color:#e2e8f0}

/* 按钮与布局 */
.btn{background:transparent;border:1px solid var(--border);color:var(--text);padding:6px 12px;border-radius:10px;cursor:pointer}
.btn:hover{border-color:#ffffff33;background:#ffffff0f}
.btn.block{width:100%}
.btn.primary{background:var(--accent);border-color:transparent;color:#0b0a0d}
.btn.primary:hover{filter:brightness(1.1)}

.layout{display:grid;grid-template-columns:280px 1fr;min-height:calc(100vh - 56px)}
.sidebar{border-right:1px solid var(--border);display:flex;flex-direction:column}
.sidebar-header{padding:12px;border-bottom:1px solid var(--border)}
.search{display:flex;align-items:center;gap:6px;margin-top:8px;background:var(--panel);border:1px solid var(--border);padding:6px 8px;border-radius:10px}
.search .icon{color:var(--muted)}
.search input{flex:1;background:transparent;border:0;outline:0;color:var(--text)}
.session-list{padding:8px;overflow:auto}
.session-item{display:flex;align-items:center;gap:6px;padding:6px;border-radius:8px}
.session-item:hover{background:#ffffff0a}
.session-item.active{background:#ffffff14}
.session-main{flex:1;background:transparent;border:0;color:inherit;text-align:left;cursor:pointer}
.session-item .title{font-size:13px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.session-item .meta{font-size:11px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.icon-btn{background:transparent;border:0;color:var(--muted);cursor:pointer;padding:6px;border-radius:8px}
.icon-btn:hover{background:#ffffff14;color:#fff}

/* 聊天区 */
.chat{display:flex;flex-direction:column;min-height:100%;position:relative}
.hero{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:56vh;padding:24px;text-align:center}
.hero-logo{width:36px;height:36px;border-radius:10px;background:linear-gradient(135deg,var(--accent-2),#f43f5e);margin-bottom:12px}
.hero h1{margin:6px 0 4px 0}
.hero p{color:var(--muted);max-width:640px}
.hero-input{margin-top:24px;display:flex;gap:8px;width:100%;max-width:640px;background:var(--panel);border:1px solid var(--border);padding:8px;border-radius:99px}
.hero-input input{flex:1;background:transparent;border:0;outline:0;color:var(--text);padding:2px 6px}

.messages{padding:18px;max-width:720px;margin:0 auto;width:100%}
.msg-card{position:relative;background:var(--panel);border:1px solid var(--border);backdrop-filter:blur(6px);border-radius:14px;padding:12px 14px;margin:10px 0;max-width:85%}
.msg-card.assistant{margin-right:auto}
.msg-card.user{margin-left:auto;border-color:rgba(52,211,153,.35);background:rgba(52,211,153,.08)}
.msg-text{white-space:pre-wrap;word-break:break-word}
.msg-actions{position:absolute;right:8px;top:8px;display:flex;gap:4px}

.composer{position:sticky;bottom:0;padding:12px 16px;border-top:1px solid var(--border);background:rgba(0,0,0,.35);backdrop-filter:blur(8px)}
.composer textarea{width:100%;max-width:720px;display:block;margin:0 auto;min-height:68px;resize:vertical;background:var(--panel);border:1px solid var(--border);color:var(--text);border-radius:12px;padding:10px;outline:none}
.composer .btn{display:block;margin:8px auto 0}

.muted{color:var(--muted)}
.hidden{display:none!important}

/* 弹窗 */
.modal{position:fixed;inset:0;background:rgba(0,0,0,.45);display:flex;align-items:center;justify-content:center;padding:16px}
.modal-content{width:100%;max-width:440px;background:#121015;border:1px solid var(--border);border-radius:12px;padding:16px}
.modal-content h3{margin:0 0 6px 0}
.modal-content input{width:100%;margin-top:10px;background:var(--panel);border:1px solid var(--border);color:var(--text);border-radius:10px;padding:8px;outline:none}
.help{font-size:12px;margin:6px 0 0 0;color:var(--muted)}
.modal-actions{margin-top:12px;display:flex;justify-content:flex-end;gap:8px}

/* 悬浮二维码按钮（页面左下角 + 列表底部内联版） */
.qr-fab{
  width:44px;height:44px;border-radius:9999;
  background:var(--panel);border:1px solid var(--border);
  display:flex;align-items:center;justify-content:center;
  position:relative;cursor:pointer
}
.qr-fab.fixed{position:fixed;left:16px;bottom:16px;z-index:50}
.qr-fab.inline{position:relative;margin:12px 0 0 4px}
.qr-icon{width:22px;height:22px;display:block}
.qr-pop{
  position:absolute;left:52px;bottom:0;width:160px;
  background:#121015;border:1px solid var(--border);border-radius:10px;
  padding:6px;display:none;box-shadow:0 6px 28px rgba(0,0,0,.45)
}
.qr-pop{max-width:min(60vw,180px);height:auto}
.qr-fab:hover .qr-pop{display:block}

/* 响应式 */
@media (max-width: 900px){
  .layout{grid-template-columns:1fr}
  .sidebar{display:none}
  .composer textarea{max-width:100%}
  .messages{max-width:100%}
}