:root{
  --bg:#ffffff;
  --bg-soft:#fafafa;
  --bg-hover:#f4f4f5;
  --line:#ececec;
  --line-2:#e2e2e2;
  --tx:#16181d;
  --tx-2:#5b616e;
  --tx-3:#9aa0aa;
  --accent:#16181d;
  --radius:12px;
  --shadow:0 1px 2px rgba(16,24,40,.04),0 8px 24px rgba(16,24,40,.06);
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;font-family:var(--font);background:var(--bg);color:var(--tx);
  font-size:15px;line-height:1.6;-webkit-font-smoothing:antialiased;
}
button,input,textarea,select{font-family:inherit;font-size:inherit;color:inherit}
a{color:inherit}

/* ---------- 登录 ---------- */
.gate{min-height:100vh;display:flex;align-items:center;justify-content:center;background:var(--bg-soft)}
.gate-card{width:340px;background:#fff;border:1px solid var(--line);border-radius:16px;padding:34px 30px;box-shadow:var(--shadow)}
.gate-logo{width:44px;height:44px;border-radius:12px;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:600;font-size:18px;margin-bottom:18px}
.gate h1{font-size:19px;margin:0 0 6px;font-weight:600}
.gate p{margin:0 0 22px;color:var(--tx-3);font-size:13px}
.gate input{width:100%;height:44px;border:1px solid var(--line-2);border-radius:10px;padding:0 14px;outline:none;background:#fff;transition:.15s}
.gate input:focus{border-color:#111;box-shadow:0 0 0 3px rgba(0,0,0,.05)}
.gate button{width:100%;height:44px;margin-top:12px;border:0;border-radius:10px;background:var(--accent);color:#fff;font-weight:500;cursor:pointer;transition:.15s}
.gate button:hover{opacity:.88}
.gate .err{color:#d93025;font-size:13px;margin-top:10px;min-height:18px}
.gate .hint{margin-top:18px;font-size:12px;color:var(--tx-3);text-align:center}

/* ---------- 主布局 ---------- */
.app{display:flex;height:100vh;overflow:hidden}
.side{width:268px;flex:0 0 268px;background:var(--bg-soft);border-right:1px solid var(--line);display:flex;flex-direction:column}
.side-top{padding:16px 16px 10px;display:flex;align-items:center;gap:10px}
.brand{display:flex;align-items:center;gap:9px;font-weight:600;font-size:15px}
.brand .dot{width:26px;height:26px;border-radius:8px;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:700}
.side-sec{padding:8px 12px 4px;font-size:11px;letter-spacing:.06em;text-transform:uppercase;color:var(--tx-3);font-weight:600}
.side-body{flex:1;overflow-y:auto;padding-bottom:16px}
.field{padding:6px 12px}
.field label{display:block;font-size:12px;color:var(--tx-2);margin-bottom:5px}
.select-wrap{position:relative}
.select-wrap::after{content:"";position:absolute;right:12px;top:50%;width:7px;height:7px;border-right:1.6px solid var(--tx-3);border-bottom:1.6px solid var(--tx-3);transform:translateY(-70%) rotate(45deg);pointer-events:none}
select{width:100%;appearance:none;-webkit-appearance:none;height:38px;border:1px solid var(--line-2);border-radius:9px;background:#fff;padding:0 30px 0 11px;outline:none;cursor:pointer;transition:.15s}
select:focus{border-color:#111}
select:disabled{background:#f5f5f5;color:var(--tx-3);cursor:not-allowed}

.btn-new{margin:6px 12px 2px;width:calc(100% - 24px);height:40px;border:1px solid var(--line-2);border-radius:10px;background:#fff;cursor:pointer;display:flex;align-items:center;justify-content:center;gap:7px;font-weight:500;transition:.15s}
.btn-new:hover{background:var(--bg-hover);border-color:#d5d5d5}

.convs{padding:4px 8px}
.conv{padding:9px 11px;border-radius:9px;cursor:pointer;font-size:13.5px;color:var(--tx-2);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;transition:.12s}
.conv:hover{background:var(--bg-hover);color:var(--tx)}
.conv.active{background:#ececec;color:var(--tx);font-weight:500}
.conv .t{display:block;overflow:hidden;text-overflow:ellipsis}

.side-foot{padding:10px 14px;border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;font-size:12px;color:var(--tx-3)}
.side-foot a{cursor:pointer;text-decoration:none;padding:4px 8px;border-radius:7px;transition:.15s}
.side-foot a:hover{background:var(--bg-hover);color:var(--tx)}

/* ---------- 聊天区 ---------- */
.main{flex:1;display:flex;flex-direction:column;min-width:0}
.topbar{height:56px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 22px;gap:14px;flex:0 0 auto}
.topbar .crumb{font-size:13.5px;color:var(--tx-2);display:flex;align-items:center;gap:8px;min-width:0}
.chip{display:inline-flex;align-items:center;gap:6px;height:26px;padding:0 10px;border-radius:999px;background:var(--bg-soft);border:1px solid var(--line);font-size:12px;color:var(--tx-2);white-space:nowrap}
.chip b{color:var(--tx);font-weight:600}
.topbar .right{display:flex;align-items:center;gap:8px}
.tbtn{height:32px;padding:0 12px;border:1px solid var(--line-2);border-radius:9px;background:#fff;cursor:pointer;font-size:13px;color:var(--tx-2);transition:.15s}
.tbtn:hover{background:var(--bg-hover);color:var(--tx)}

.chat{flex:1;overflow-y:auto;padding:28px 0}
.chat-inner{max-width:800px;margin:0 auto;padding:0 22px}
.welcome{text-align:center;padding:14vh 0 0;color:var(--tx-3)}
.welcome .big{width:56px;height:56px;border-radius:16px;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-size:22px;font-weight:700;margin:0 auto 18px}
.welcome h2{color:var(--tx);font-size:20px;margin:0 0 8px;font-weight:600}
.welcome p{margin:0;font-size:13.5px}
.hints{display:grid;grid-template-columns:1fr 1fr;gap:10px;max-width:560px;margin:26px auto 0}
.hint-card{border:1px solid var(--line);border-radius:11px;padding:12px 14px;text-align:left;cursor:pointer;background:#fff;transition:.15s}
.hint-card:hover{border-color:#d0d0d0;box-shadow:var(--shadow)}
.hint-card b{display:block;font-size:13px;margin-bottom:2px;color:var(--tx)}
.hint-card span{font-size:12.5px;color:var(--tx-3)}

.msg{display:flex;gap:14px;margin-bottom:24px;align-items:flex-start}
.msg .av{width:30px;height:30px;flex:0 0 30px;border-radius:9px;display:flex;align-items:center;justify-content:center;font-size:12.5px;font-weight:600}
.msg.user .av{background:#f0f0f0;color:#555}
.msg.ai .av{background:var(--accent);color:#fff}
.msg .bubble{flex:1;min-width:0;padding-top:3px}
.msg .who{font-size:12px;color:var(--tx-3);margin-bottom:5px}
.msg .body{white-space:pre-wrap;word-wrap:break-word;overflow-wrap:anywhere}
.msg.ai .body{white-space:normal}
.msg .body p{margin:0 0 10px}
.msg .body p:last-child{margin-bottom:0}
.msg .body pre{background:#f7f7f8;border:1px solid var(--line);border-radius:10px;padding:12px 14px;overflow-x:auto;font-size:13px;line-height:1.5;margin:8px 0}
.msg .body code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:13px;background:#f2f2f4;padding:1px 5px;border-radius:5px}
.msg .body pre code{background:none;padding:0}
.msg .meta{font-size:11.5px;color:var(--tx-3);margin-top:7px}
.msg .acts{margin-top:8px;display:flex;gap:6px;opacity:0;transition:.15s}
.msg:hover .acts{opacity:1}
.msg .acts button{border:1px solid var(--line);background:#fff;border-radius:7px;padding:3px 9px;font-size:12px;color:var(--tx-2);cursor:pointer}
.msg .acts button:hover{background:var(--bg-hover)}
.cursor{display:inline-block;width:7px;height:16px;background:#111;vertical-align:-2px;animation:blink 1s steps(2) infinite;margin-left:2px}
@keyframes blink{0%,50%{opacity:1}51%,100%{opacity:0}}
.typing{color:var(--tx-3);font-size:13px}

/* ---------- 输入 ---------- */
.composer{flex:0 0 auto;padding:10px 22px 22px;background:linear-gradient(to top,#fff 60%,rgba(255,255,255,0))}
.composer-inner{max-width:800px;margin:0 auto}
.box{border:1px solid var(--line-2);border-radius:15px;background:#fff;box-shadow:var(--shadow);transition:.15s;overflow:hidden}
.box:focus-within{border-color:#c9c9c9}
.box textarea{width:100%;border:0;outline:none;resize:none;padding:15px 16px 4px;max-height:200px;min-height:24px;background:transparent;line-height:1.6}
.box-bar{display:flex;align-items:center;justify-content:space-between;padding:6px 10px 9px 14px;gap:10px}
.box-bar .left{font-size:12px;color:var(--tx-3);display:flex;gap:10px;align-items:center;min-width:0}
.box-bar .left .m{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.send{height:34px;min-width:76px;padding:0 16px;border:0;border-radius:9px;background:var(--accent);color:#fff;font-weight:500;cursor:pointer;transition:.15s}
.send:disabled{background:#dcdcdc;cursor:not-allowed}
.send:not(:disabled):hover{opacity:.88}
.tip{text-align:center;font-size:11.5px;color:var(--tx-3);margin-top:9px}

.err-bar{max-width:800px;margin:0 auto 10px;background:#fff5f5;border:1px solid #ffd7d7;color:#c0392b;border-radius:10px;padding:9px 13px;font-size:13px}
.err-bar.hide{display:none}
.toast{position:fixed;left:50%;bottom:34px;transform:translateX(-50%);background:#16181d;color:#fff;padding:9px 16px;border-radius:10px;font-size:13px;opacity:0;pointer-events:none;transition:.25s;z-index:99}
.toast.show{opacity:1}

.hamb{display:none}
@media(max-width:820px){
  .side{position:fixed;z-index:40;left:0;top:0;bottom:0;transform:translateX(-100%);transition:.2s;box-shadow:var(--shadow)}
  .side.open{transform:none}
  .hamb{display:flex;align-items:center;justify-content:center;width:34px;height:34px;border:1px solid var(--line-2);border-radius:9px;background:#fff;cursor:pointer}
  .hints{grid-template-columns:1fr}
}