:root{color-scheme:light;--bg:#ffffff;--sidebar:#fbfbfa;--text:#1d211c;--muted:#737b84;--line:#ecefeb;--soft-line:#f4f5f3;--panel:#ffffff;--accent:#d8423a;--accent-dark:#ba332d;--green:#123f2b;--shadow:0 14px 36px rgba(21,27,23,0.08)}*{box-sizing:border-box}body,html{margin:0;min-height:100%;background:var(--bg);color:var(--text);font-family:Inter,Arial,Microsoft YaHei,sans-serif}button,input,textarea{font:inherit}button{cursor:pointer}.app-shell{display:grid;grid-template-columns:270px minmax(0,1fr);min-height:100vh;background:var(--bg)}.app-shell.sidebar-closed{grid-template-columns:0 minmax(0,1fr)}.sidebar{overflow:hidden;border-right:1px solid var(--line);background:var(--sidebar);padding:30px 22px;transition:width .2s ease,padding .2s ease}.sidebar-closed .sidebar{width:0;padding-left:0;padding-right:0;border-right:0}.brand{display:flex;align-items:center;gap:10px;font-size:22px;font-weight:800}.avatar{display:grid;place-items:center;border-radius:50%;background:var(--accent);color:#fff;box-shadow:inset 0 -10px 18px rgba(0,0,0,.12)}.avatar.small{width:36px;height:36px;font-size:13px}.avatar.large{width:74px;height:74px;margin:0 auto 20px;border:5px solid #fff;font-size:22px;box-shadow:0 10px 28px rgba(216,66,58,.22)}.new-chat{display:inline-flex;align-items:center;gap:9px;margin:46px 0 34px;border:1px solid var(--line);border-radius:8px;padding:14px 18px;background:#fff;color:var(--text);font-size:17px;box-shadow:0 8px 20px rgba(21,27,23,.06)}.new-chat span{font-size:20px;line-height:1}.history{display:grid;grid-gap:8px;gap:8px}.empty-history,.history-label{margin:0;color:var(--muted);font-size:13px}.history-item{border:0;border-radius:8px;padding:10px 8px;background:transparent;color:var(--text);text-align:left;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.history-item.active,.history-item:hover{background:#f0f1ef}.workspace{min-width:0;display:grid;grid-template-rows:58px minmax(0,1fr);min-height:100vh}.topbar{display:flex;align-items:center;border-bottom:1px solid var(--line);padding:0 28px;background:#fff}.icon-button,.send-button,.tool-button{display:grid;place-items:center;border:0;border-radius:50%;background:transparent;color:#5d6670}.icon-button{width:34px;height:34px;font-size:20px}.welcome{display:flex;flex-direction:column;align-items:center;padding:min(17vh,140px) 24px 48px;text-align:center}.welcome h1{margin:0;font-size:28px;font-weight:500;letter-spacing:0}.welcome p{max-width:660px;margin:16px auto 48px;color:#27312b;font-size:16px;line-height:1.75}.composer{width:min(760px,calc(100vw - 40px));margin:0 auto;border:1px solid var(--line);border-radius:16px;background:var(--panel);box-shadow:var(--shadow);overflow:hidden}.composer-centered{margin-bottom:28px}.composer textarea{display:block;width:100%;min-height:74px;resize:none;border:0;outline:none;padding:18px 22px 8px;color:var(--text);background:transparent;line-height:1.5}.composer textarea::placeholder{color:#a0a7ae}.composer-footer{display:flex;align-items:center;gap:10px;padding:8px 12px 12px}.composer-spacer{flex:1 1}.tool-button{width:36px;height:36px;font-size:25px}.tool-button:hover{background:#f2f4f3}.send-button{width:42px;height:42px;background:#e7ebee;color:#73808a;font-size:24px}.send-button:not(:disabled){background:#e5e9ec;color:#6c7881}.send-button:hover:not(:disabled){background:var(--green);color:#fff}.send-button:disabled{opacity:.6;cursor:not-allowed}.notice{color:#8a5b12;font-size:12px}.suggestions{width:min(760px,calc(100vw - 40px));display:flex;flex-wrap:wrap;gap:10px;justify-content:flex-start;margin:0 auto;text-align:left}.suggestions span{flex-basis:100%;color:#a1a7ad;font-size:13px}.suggestions button{border:1px solid var(--line);border-radius:8px;background:#fff;color:#68717a;padding:10px 14px;text-align:left}.suggestions button:hover{border-color:#cfd6d1;color:var(--text)}.chat-panel{min-height:0;display:grid;grid-template-rows:minmax(0,1fr) auto;padding:0 0 24px}.messages{overflow:auto;padding:34px 34px 22px}.message{display:grid;grid-gap:8px;gap:8px;max-width:890px;margin:0 0 24px}.message.user{margin-left:auto;max-width:720px}.role{color:var(--muted);font-size:13px;font-weight:700}.user .role{text-align:right}.bubble{white-space:pre-wrap;line-height:1.75;border:1px solid var(--line);border-radius:8px;padding:18px;background:var(--panel);box-shadow:0 10px 30px rgba(23,32,27,.05)}.assistant .bubble{border-left:4px solid #198251}.user .bubble{background:var(--green);color:#fff;border-color:var(--green)}.attachments{display:grid;grid-gap:8px;gap:8px;padding:12px 12px 0}.attachment{display:grid;grid-template-columns:44px minmax(0,1fr) 28px;align-items:center;grid-gap:10px;gap:10px;border:1px solid var(--soft-line);border-radius:10px;padding:8px;background:#fafbf9;text-align:left}.attachment img,.file-icon{width:44px;height:44px;border-radius:8px;object-fit:cover}.file-icon{display:grid;place-items:center;background:#eef2f0;color:#67736c;font-size:11px;font-weight:700}.attachment strong{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:13px}.attachment small{color:var(--muted);font-size:12px}.attachment button{width:26px;height:26px;border:0;border-radius:50%;background:transparent;color:#89929a;font-size:18px}.attachment button:hover{background:#eef1ef;color:var(--text)}.message-files{display:flex;flex-wrap:wrap;gap:6px;margin-top:12px}.message-files span{border-radius:999px;background:rgba(255,255,255,.14);padding:4px 8px;font-size:12px}@media (max-width:860px){.app-shell,.app-shell.sidebar-closed{grid-template-columns:1fr}.sidebar{display:none}.welcome{padding-top:60px}.messages{padding:22px 16px}}