/* Tutor switch */
.tsw{display:flex;gap:4px;padding:4px;margin:0 0 12px;border-radius:16px;background:var(--s2);border:1px solid var(--bd)}
.tsw button{flex:1;min-height:44px;border:0;border-radius:12px;background:none;font-weight:700;font-size:14.5px;color:var(--mu);white-space:nowrap}
.tsw button.on{background:var(--s1);color:var(--tx);box-shadow:var(--sh2);outline:1.5px solid color-mix(in srgb,var(--pri) 45%,transparent)}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
/* layout */
.tcw{display:grid;grid-template-columns:minmax(0,1fr);gap:14px}.tcmain,.tcside{min-width:0}
.tcside{display:none;background:var(--s1);border:1px solid var(--bd);border-radius:var(--r);padding:10px;box-shadow:var(--sh2)}
.tcw.side .tcside{display:block}.tcw.side .tcmain{display:none}
.tcsh{display:flex;align-items:center;justify-content:space-between;padding:4px 4px 8px}
.tclist{display:flex;flex-direction:column;gap:4px;max-height:70vh;overflow:auto}
.tci{display:flex;align-items:stretch;border-radius:12px}.tci.on{background:var(--s2)}
.tco{flex:1;min-width:0;text-align:left;background:none;border:0;padding:9px 10px;border-radius:12px}
.tco b{display:block;font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.tco small{color:var(--mu);font-size:12px}
.tcx{min-width:40px;background:none;border:0;color:var(--mu);border-radius:10px}.tcx:hover{color:var(--no)}
.tcmain{display:flex;flex-direction:column;min-height:calc(100dvh - 300px)}
.tcbar{display:flex;gap:8px;align-items:center;margin-bottom:10px}
.tcsrc{flex:1;min-width:0}.tcsrc select{width:100%;-webkit-appearance:none;appearance:none;padding-right:34px!important;background-image:linear-gradient(45deg,transparent 50%,var(--mu) 50%),linear-gradient(135deg,var(--mu) 50%,transparent 50%)!important;background-position:calc(100% - 18px) 50%,calc(100% - 13px) 50%!important;background-size:5px 5px!important;background-repeat:no-repeat!important;min-height:44px;border-radius:14px;padding:0 12px;font-weight:600;font-size:14.5px;background:var(--s1);color:var(--tx);border:1px solid var(--bd)}
.tcbar .chip{min-height:44px;white-space:nowrap}
.tchint{font-size:13.5px;color:var(--mu);background:var(--s2);border-radius:12px;padding:8px 12px;margin-bottom:10px}
.tcmsgs{flex:1;display:flex;flex-direction:column;gap:12px;padding:4px 0 10px}
.tcm{display:flex;gap:8px;align-items:flex-start;min-width:0}.tcm.me{justify-content:flex-end}
.tcb{min-width:0;max-width:100%;padding:11px 14px;border-radius:18px;background:var(--s1);border:1px solid var(--bd);box-shadow:var(--sh2);overflow-wrap:break-word}
.tcm.ai .tcb{flex:1;border-top-left-radius:6px}
.tcm.me .tcb{max-width:85%;background:var(--accent);color:#fff;border:0;border-top-right-radius:6px;white-space:pre-wrap}
.tcb.md p{margin:.35em 0}.tcb.md ul,.tcb.md ol{padding-left:1.2em;margin:.35em 0}.tcb.md .tscroll{margin:.5em -4px}
.tcb.err{border-color:var(--no)}
.tcav{width:34px;height:34px;flex:none;border-radius:50%;display:grid;place-items:center;background:var(--accent);color:#fff;font-weight:800;box-shadow:0 4px 12px color-mix(in srgb,var(--pri) 40%,transparent)}
.tcav.sm{width:28px;height:28px;font-size:13px;margin-top:4px}
.tcempty{text-align:center;padding:18px 8px}.tcempty .tcav{width:56px;height:56px;font-size:24px;margin:0 auto 10px}
.tcempty p{max-width:520px;margin:.5em auto 1em}.tcst{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}
.tcst .chip{text-align:left;min-height:40px;white-space:normal;max-width:100%;flex:0 1 auto}
.cite{display:inline-flex;align-items:center;min-height:24px;padding:0 8px;margin:0 2px;border-radius:999px;border:1px solid color-mix(in srgb,var(--pri) 45%,transparent);background:color-mix(in srgb,var(--pri) 14%,transparent);color:var(--pri-tx);font-size:12px;font-weight:700;vertical-align:1px}
.tcfoot{display:flex;flex-wrap:wrap;gap:8px;align-items:center;justify-content:space-between;margin-top:8px;padding-top:8px;border-top:1px dashed var(--bd)}
.tcsrcl{font-size:12.5px;color:var(--mu);font-weight:600;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.tcsay{min-height:36px;padding:0 12px;border-radius:999px;border:1px solid var(--bd);background:var(--s2);font-size:13px;font-weight:700;margin-left:auto}.tcsay.on{background:var(--accent);color:#fff;border:0}
.typing{display:flex;gap:5px;flex:0 0 auto!important;padding:14px 16px}.typing i{width:8px;height:8px;border-radius:50%;background:var(--pri);animation:tcb 1s infinite ease-in-out}
.typing i:nth-child(2){animation-delay:.15s}.typing i:nth-child(3){animation-delay:.3s}@keyframes tcb{0%,80%,100%{opacity:.3;transform:translateY(0)}40%{opacity:1;transform:translateY(-4px)}}
.tcchips{display:flex;gap:8px;overflow-x:auto;padding:6px 2px 8px;scrollbar-width:none;-webkit-overflow-scrolling:touch}.tcchips::-webkit-scrollbar{display:none}
.tchip{flex:none;min-height:40px;white-space:nowrap;display:inline-flex;gap:6px;align-items:center}
.tccomp{position:sticky;bottom:calc(76px + env(safe-area-inset-bottom));display:flex;gap:8px;align-items:flex-end;padding:8px;border-radius:22px;background:var(--s1);border:1px solid var(--bd);box-shadow:var(--sh)}
.tccomp textarea{flex:1;min-width:0;min-height:44px;max-height:140px;resize:none;border:0;background:none;color:var(--tx);font:16px/1.4 inherit;font-family:inherit;padding:11px 4px;outline:none}
.tcmic,.tcsend{flex:none;width:44px;height:44px;min-height:44px;border-radius:50%;padding:0;display:grid;place-items:center;font-size:18px}
.tcmic{border:1px solid var(--bd);background:var(--s2)}.tcmic.on{background:var(--no);color:#fff;animation:tcp 1.2s infinite}
@keyframes tcp{0%{box-shadow:0 0 0 0 rgba(244,63,94,.5)}100%{box-shadow:0 0 0 12px rgba(244,63,94,0)}}
/* quiz */
.tcqh{font-size:12.5px;font-weight:800;text-transform:uppercase;letter-spacing:.04em;color:var(--pri-tx);margin-bottom:4px}
.tcopts{display:flex;flex-direction:column;gap:8px;margin:10px 0}
.tcopt{display:flex;gap:10px;align-items:flex-start;text-align:left;min-height:48px;padding:10px 12px;border-radius:14px;border:1.5px solid var(--bd);background:var(--s2);font-size:15px}
.tcopt b{flex:none;width:26px;height:26px;border-radius:50%;display:grid;place-items:center;background:var(--s3);font-size:13px}
.tcopt span{min-width:0}.tcopt small{display:block;color:var(--mu);font-size:13px;margin-top:4px}
.tcopt:not(:disabled):hover{border-color:var(--pri)}
.tcopt.ok{border-color:var(--ok);background:color-mix(in srgb,var(--ok) 13%,var(--s1))}.tcopt.ok b{background:var(--ok);color:#fff}
.tcopt.no{border-color:var(--no);background:color-mix(in srgb,var(--no) 12%,var(--s1))}.tcopt.no b{background:var(--no);color:#fff}
.tcopt.dim{opacity:.75}.tcopt:disabled{cursor:default;color:var(--tx)}
.tcfb{padding:10px 12px;border-radius:12px;margin:6px 0 10px;font-weight:600}.tcfb>div{font-weight:400;margin-top:4px}
.tcfb.ok{background:color-mix(in srgb,var(--ok) 14%,transparent)}.tcfb.no{background:color-mix(in srgb,var(--no) 12%,transparent)}
.tcb .row{display:flex;flex-wrap:wrap;gap:8px;margin-top:6px}
.tccard{display:flex;flex-direction:column;gap:2px;padding:9px 11px;border-radius:12px;background:var(--s2);margin:6px 0}.tccard span{color:var(--mu);font-size:14px}
.tcpop{position:fixed;inset:auto 12px calc(90px + env(safe-area-inset-bottom)) 12px;max-width:560px;margin:0 auto;z-index:30;background:var(--s1);border:1px solid var(--bd);border-radius:18px;padding:14px;box-shadow:0 18px 50px rgba(0,0,0,.35);max-height:55vh;overflow:auto}
.tcpt{white-space:pre-wrap;font-size:14.5px;margin:6px 0 10px}
.tcplan{margin-bottom:12px}.tcpi{display:flex;gap:10px;align-items:center;min-height:44px;border-bottom:1px solid var(--bd)}.tcpi span{flex:1}.tcpi small{color:var(--mu)}
.tcpi input:checked+span{text-decoration:line-through;color:var(--mu)}
@media (min-width:900px){main.v-chat{max-width:1100px}.v-chat .tcw{grid-template-columns:280px minmax(0,1fr)}.v-chat .tcw .tcside,.v-chat .tcw.side .tcside{display:block;position:sticky;top:90px;align-self:start}
 .v-chat .tcw.side .tcmain{display:flex}.tcthr{display:none!important}.tccomp{bottom:calc(84px + env(safe-area-inset-bottom))}}
@media (max-width:420px){.tcbar .tcthr span{display:none}.tsw button{font-size:13.5px}}