:root{--bg:#f5f6f8;--surface:#fff;--ink:#1e2430;--muted:#5c6575;--line:#dfe3ea;--accent:#2f5bea;--accent-soft:#e8edfc;--amber:#b8690f;--amber-soft:#fbf1e3;--green:#237d54;--green-soft:#e4f3eb;--red:#c2402a;--red-soft:#fbeae6}@media (prefers-color-scheme:dark){:root{--bg:#12151c;--surface:#1a1f29;--ink:#e8eaf0;--muted:#98a1b3;--line:#2a3140;--accent:#7e97ff;--accent-soft:#232b44;--amber:#e09a46;--amber-soft:#332818;--green:#4fbf8f;--green-soft:#16291f;--red:#e0664d;--red-soft:#33201b}}*{box-sizing:border-box}body{background:var(--bg);color:var(--ink);margin:0;font:15px/1.75 Noto Sans SC,PingFang SC,Microsoft YaHei,system-ui,sans-serif}.topbar{background:var(--surface);border-bottom:1px solid var(--line)}.topbar-inner{max-width:960px;margin:0 auto;padding:12px 20px 0}.brand-row{align-items:center;gap:12px;display:flex}.brand{font-size:17px;font-weight:700}.brand span{color:var(--accent)}.brand-spacer{flex:1}.key-dot{background:var(--line);vertical-align:middle;border-radius:50%;width:8px;height:8px;margin-left:4px;display:inline-block}.key-dot.on{background:var(--green)}.key-panel{background:var(--bg);border:1px solid var(--line);border-radius:10px;margin-top:10px;padding:12px 14px}.key-panel input{flex:1;min-width:240px}.nav{gap:2px;margin-top:8px;display:flex}.nav button{color:var(--muted);font:inherit;cursor:pointer;background:0 0;border:none;border-bottom:2px solid #0000;padding:8px 14px;font-size:14px;font-weight:500}.nav button.on{color:var(--accent);border-bottom-color:var(--accent);font-weight:700}.nav .nav-admin{margin-left:auto;font-size:13px}.stage{max-width:960px;margin:0 auto;padding:24px 20px 72px}button:focus-visible,.opt:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.btn{background:var(--accent);color:#fff;font:inherit;cursor:pointer;border:none;border-radius:9px;padding:10px 20px;font-weight:700}.btn.ghost{background:var(--surface);color:var(--accent);border:1px solid var(--accent)}.btn.sm{padding:5px 12px;font-size:13px;font-weight:500}.btn:disabled{opacity:.45;cursor:not-allowed}.link{color:var(--accent);font:inherit;cursor:pointer;background:0 0;border:none;padding:0;font-size:13px}.link.danger{color:var(--red)}.link:disabled{opacity:.35;cursor:default}.card{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:16px 18px}.pill{color:var(--muted);background:var(--bg);border:1px solid var(--line);border-radius:999px;padding:1px 10px;font-size:12px;font-weight:700;display:inline-block}.answer-pick{flex-wrap:wrap;align-items:center;gap:4px;display:inline-flex}.answer-pick button.pill{font:inherit;cursor:pointer;font-size:12px}.pill.b{color:var(--accent);background:var(--accent-soft);border-color:#0000}.pill.g{color:var(--green);background:var(--green-soft);border-color:#0000}.pill.a{color:var(--amber);background:var(--amber-soft);border-color:#0000}.pill.r{color:var(--red);background:var(--red-soft);border-color:#0000}.muted{color:var(--muted)}.small{font-size:13px}.panel-error{color:var(--red);font-size:13.5px}.dash-head{flex-wrap:wrap;justify-content:space-between;align-items:baseline;gap:8px;display:flex}.dash-head h2{margin:0;font-size:20px}.count-down{color:var(--muted);font-size:14px}.count-down b{color:var(--amber);font-variant-numeric:tabular-nums;font-size:20px}.domain-bars{flex-direction:column;gap:12px;margin:18px 0;display:flex}.dbar{grid-template-columns:120px 1fr 52px 56px;align-items:center;gap:12px;font-size:14px;display:grid}.dbar-name{text-overflow:ellipsis;white-space:nowrap;overflow:hidden}.dbar .track{background:var(--line);border-radius:999px;height:10px;overflow:hidden}.dbar .fill{background:var(--accent);border-radius:999px;height:100%;transition:width .2s;display:block}.dbar .fill.warn{background:var(--amber)}.dbar .pct{text-align:right;font-variant-numeric:tabular-nums;font-weight:700}.dbar .pct.warn{color:var(--amber)}.dbar-count{color:var(--muted);text-align:right;font-variant-numeric:tabular-nums;font-size:12px}.dash-grid{grid-template-columns:1.4fr 1fr;gap:14px;margin-top:6px;display:grid}@media (width<=720px){.dash-grid{grid-template-columns:1fr}}.cta-card{background:var(--accent-soft);border:1px solid var(--accent);border-radius:12px;flex-direction:column;gap:10px;padding:18px;display:flex}.cta-card h3{margin:0;font-size:16px}.side-list{flex-direction:column;gap:12px;display:flex}.side-item{justify-content:space-between;align-items:center;gap:8px;font-size:14px;display:flex}.quiz-top{justify-content:space-between;align-items:center;margin-bottom:14px;font-size:14px;display:flex}.stem{max-width:40em;margin:0 0 16px;font-size:16.5px;font-weight:500;line-height:1.75}.stem-imgs{flex-wrap:wrap;gap:8px;margin:0 0 16px;display:flex}.stem-imgs img{border:1px solid var(--line);background:#fff;border-radius:8px;max-width:100%;max-height:280px}.stem-imgs.sm{margin:6px 0;display:flex}.stem-imgs.sm img{max-height:120px}.opts{flex-direction:column;gap:10px;max-width:620px;display:flex}.opt{text-align:left;background:var(--surface);border:1.5px solid var(--line);font:inherit;color:var(--ink);cursor:pointer;border-radius:10px;padding:11px 14px}.opt:hover:not(:disabled){border-color:var(--accent)}.opt:disabled{cursor:default}.opt.picked{border-color:var(--accent);background:var(--accent-soft)}.opt-box{opacity:.7;width:1.4em;display:inline-block}.opt.correct{border-color:var(--green);background:var(--green-soft);font-weight:700}.opt.wrong{border-color:var(--red);background:var(--red-soft)}.explain{max-width:620px;margin-top:16px}.verdict-line{margin-bottom:6px;font-weight:700}.verdict-line.ok{color:var(--green)}.verdict-line.no{color:var(--red)}.explain-text{color:var(--muted);white-space:pre-wrap;font-size:14px}.source-chip{color:var(--accent);background:var(--accent-soft);border-radius:6px;margin-top:8px;padding:2px 8px;font-size:12px;display:inline-block}.quiz-actions{flex-wrap:wrap;align-items:center;gap:10px;margin-top:14px;display:flex}.ai-thread{flex-direction:column;gap:8px;max-width:620px;margin-top:12px;display:flex}.bub{white-space:pre-wrap;word-break:break-word;border-radius:10px;max-width:92%;padding:8px 12px;font-size:14px}.bub.me{background:var(--accent-soft);border:1px solid var(--accent);align-self:flex-end}.bub.ai{background:var(--surface);border:1px solid var(--line)}.bub-fail{color:var(--red);margin-top:6px;font-size:13px}.bub-tools{gap:12px;margin-top:6px;font-size:13px;display:flex}:is(.stage:has(.quiz-layout),.stage:has(.mm-layout)){max-width:1360px;padding:16px 24px}.quiz-layout{grid-template-columns:minmax(0,1fr) minmax(420px,46%);align-items:stretch;gap:24px;height:calc(100dvh - 178px);min-height:320px;display:grid}.quiz-main{min-width:0;padding-right:2px;overflow-y:auto}.tutor-panel{background:var(--surface);border:1px solid var(--line);border-radius:12px;flex-direction:column;min-height:0;display:flex;overflow:hidden}.tutor-head{border-bottom:1px solid var(--line);justify-content:space-between;align-items:baseline;gap:8px;padding:10px 12px;font-size:14px;font-weight:600;display:flex}.tutor-thread{flex-direction:column;flex:1;gap:8px;padding:12px;display:flex;overflow-y:auto}.tutor-thread>.btn{align-self:flex-start}.tutor-empty{text-align:center;flex-direction:column;gap:10px;max-width:24em;margin:auto;display:flex}.tutor-empty p{margin:0}.preset-bar{border-top:1px solid var(--line);flex-wrap:wrap;gap:6px;padding:8px 10px 0;display:flex}.preset-bar .preset-btn{padding:4px 10px;font-size:12px}.preset-btn{background:var(--bg);border:1px solid var(--line);font:inherit;color:var(--ink);cursor:pointer;border-radius:999px;padding:6px 14px;font-size:13px}.preset-btn:hover:not(:disabled){border-color:var(--accent);color:var(--accent)}.preset-btn:disabled{opacity:.45;cursor:not-allowed}.tutor-input{gap:8px;padding:8px 10px 10px;display:flex}.tutor-input input{flex:1;min-width:0}.src-row{flex-wrap:wrap;gap:6px;margin-top:6px;display:flex}.src-row .source-chip{cursor:help;margin-top:0}@media (width<=900px){.quiz-layout{grid-template-columns:1fr;height:auto}.tutor-panel{height:clamp(320px,42dvh,460px)}}@media (width<=720px){.tutor-panel{height:clamp(420px,66dvh,640px)}.tutor-thread{min-height:200px}}.typing{color:var(--muted);align-items:baseline;gap:3px;display:inline-flex}.typing i{background:currentColor;border-radius:50%;width:4px;height:4px;animation:1.2s infinite both typing-blink}.typing i:nth-child(2){animation-delay:.2s}.typing i:nth-child(3){animation-delay:.4s}@keyframes typing-blink{0%,80%,to{opacity:.25}40%{opacity:1}}.practice-done{text-align:center;padding:48px 0}.practice-done h2{margin:0 0 8px;font-size:22px}.wrong-list{flex-direction:column;gap:10px;margin-top:14px;display:flex}.wrong-item{background:var(--surface);border:1px solid var(--line);border-radius:10px;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:10px;padding:10px 14px;font-size:14px;display:flex}.wb-tabs{border-bottom:1px solid var(--line);gap:2px;margin:16px 0 14px;display:flex}.wb-tabs button{color:var(--muted);font:inherit;cursor:pointer;background:0 0;border:none;border-bottom:2px solid #0000;padding:6px 12px;font-size:13.5px}.wb-tabs button.on{color:var(--accent);border-bottom-color:var(--accent);font-weight:700}.dropzone{border:2px dashed var(--line);text-align:center;color:var(--muted);cursor:pointer;border-radius:12px;margin-bottom:16px;padding:22px;font-size:14px}.dropzone.drag{border-color:var(--accent);background:var(--accent-soft)}.dropzone b{color:var(--accent)}.ingest-table{border-collapse:collapse;width:100%;font-size:14px}.ingest-table th,.ingest-table td{text-align:left;border-bottom:1px solid var(--line);vertical-align:top;padding:9px 10px}.ingest-table th{letter-spacing:.06em;color:var(--muted);font-size:12px;font-weight:700}.rq{background:var(--bg);border:1px solid var(--line);border-radius:10px;justify-content:space-between;align-items:flex-start;gap:10px;margin-top:8px;padding:10px 14px;font-size:14px;display:flex}.rq.dropped{opacity:.45}.rq.dropped>span{text-decoration:line-through}.row-list{flex-direction:column;gap:8px;margin-top:12px;display:flex}.row-item{background:var(--surface);border:1px solid var(--line);border-radius:10px;flex-wrap:wrap;justify-content:space-between;align-items:flex-start;gap:10px;padding:10px 14px;font-size:14px;display:flex}.row-item .grow{flex:auto;min-width:0}.form-col{flex-direction:column;gap:8px;margin-top:14px;display:flex}.form-row{flex-wrap:wrap;align-items:center;gap:8px;display:flex}input[type=text],input[type=date],input[type=search],input[type=email],input[type=password],input:not([type]),textarea,select{background:var(--surface);color:inherit;border:1px solid var(--line);font:inherit;border-radius:8px;padding:8px 10px;font-size:14px}.form-col input,.form-col textarea{width:100%}.form-row input[type=text],.form-row input:not([type]){flex:1}textarea{resize:vertical}.search-hit{border:1px dashed var(--line);border-radius:8px;margin-top:8px;padding:8px 10px;font-size:13px}.search-hit p{white-space:pre-wrap;color:var(--muted);margin:4px 0 0}.hit-source{color:var(--accent);font-size:12px}.notice{border-radius:10px;margin-bottom:12px;padding:10px 14px;font-size:13.5px}.notice.amber{background:var(--amber-soft);border:1px solid var(--amber);color:var(--amber)}.notice.red{background:var(--red-soft);border:1px solid var(--red);color:var(--red)}.banner-error{background:var(--red-soft);border:1px solid var(--red);max-width:960px;color:var(--red);border-radius:8px;margin:12px auto 0;padding:10px 14px;font-size:14px}.mm-layout{align-items:flex-start;gap:14px;display:flex}.mm-toc{flex:0 0 200px;max-height:calc(100vh - 180px);padding:10px 8px;overflow-y:auto}.mm-toc-head{margin:0 0 6px 8px}.mm-toc-item{text-align:left;width:100%;color:var(--ink);cursor:pointer;text-overflow:ellipsis;white-space:nowrap;background:0 0;border:none;border-radius:8px;padding:7px 10px;font-size:13px;display:block;overflow:hidden}.mm-toc-item:hover{color:var(--accent)}.mm-toc-item.on{color:var(--accent);background:var(--accent-soft);font-weight:700}.mm-main{flex:1;min-width:0}.mm-layout .tutor-panel{flex:0 0 340px;height:calc(100dvh - 178px)}.mm-select{width:100%;margin-bottom:10px;display:none}.mm-main .mindmap-svg{height:calc(100vh - 230px);min-height:360px}@media (width<=900px){.mm-toc{display:none}.mm-select{display:block}.mm-main .mindmap-svg{height:calc(100vh - 260px)}.mm-layout{flex-direction:column}.mm-layout .tutor-panel{flex:none;width:100%}}.mm-stage{padding:8px}.mm-wrap{height:100%;position:relative}.mindmap-svg{width:100%;height:64vh;min-height:320px;color:var(--ink);display:block}.mm-fit{color:var(--muted);background:var(--surface);border:1px solid var(--line);cursor:pointer;opacity:.85;border-radius:8px;padding:4px 10px;font-size:12px;position:absolute;bottom:10px;right:10px}.mm-fit:hover{color:var(--accent);opacity:1}.mm-side{flex-wrap:wrap;align-items:stretch;gap:12px;margin-top:10px;display:flex}.mm-side .mm-stage{border:1px solid var(--line);border-radius:10px;flex:360px;min-width:280px}.mm-side .mindmap-svg{height:420px;min-height:260px}.mm-source{border:1px solid var(--line);background:#fff;border-radius:10px;flex:0 320px;max-height:420px;overflow:auto}.mm-source img{width:100%;display:block}.acct{align-items:center;gap:10px;display:flex}.acct-email{text-overflow:ellipsis;white-space:nowrap;max-width:180px;color:var(--muted);overflow:hidden}.acct-email:hover{color:var(--accent)}.acct-email-short{display:none}.credit-pill{color:var(--accent);background:var(--accent-soft);white-space:nowrap;border-radius:999px;align-items:center;gap:4px;padding:2px 10px;font-size:12.5px;font-weight:700;display:inline-flex}.credit-pill.warn{color:var(--amber);background:var(--amber-soft)}.banner-info{background:var(--green-soft);max-width:960px;color:var(--green);border-radius:10px;justify-content:space-between;align-items:center;gap:12px;margin:12px auto 0;padding:10px 14px;font-size:14px;display:flex}.modal-backdrop{z-index:50;background:#14182073;justify-content:center;align-items:center;padding:20px;display:flex;position:fixed;inset:0}.modal{background:var(--surface);border:1px solid var(--line);border-radius:14px;width:100%;max-height:calc(100vh - 40px);padding:18px 20px 20px;overflow-y:auto;box-shadow:0 20px 60px #00000040}.modal-head{justify-content:space-between;align-items:center;margin-bottom:10px;font-size:16px;display:flex}.auth-form{flex-direction:column;gap:10px;display:flex}.auth-form input{width:100%}.pack-card{border:1px solid var(--accent);background:var(--accent-soft);border-radius:10px;justify-content:space-between;align-items:center;padding:12px 14px;display:flex}.pack-price{color:var(--accent);font-size:20px;font-weight:700}.pay-types{gap:8px;margin-top:12px;display:flex}.pay-type{border:1px solid var(--line);background:var(--surface);color:inherit;font:inherit;cursor:pointer;border-radius:9px;flex:1;padding:8px}.pay-type.on{border-color:var(--accent);color:var(--accent);background:var(--accent-soft);font-weight:700}.pay-qr{border:1px solid var(--line);background:#fff;border-radius:10px;width:220px;height:220px}.guest-home{grid-template-columns:1.4fr 1fr;gap:14px;display:grid}@media (width<=720px){.guest-home{grid-template-columns:1fr}}.tutor-lock{text-align:center;flex-direction:column;align-items:center;gap:10px;max-width:24em;margin:auto;display:flex}.tutor-lock p{margin:0}.sys-grid{flex-direction:column;gap:14px;display:flex}.table-wrap{overflow-x:auto}.sys-table{border-collapse:collapse;white-space:nowrap;width:100%;font-size:13.5px}.sys-table th,.sys-table td{text-align:left;border-bottom:1px solid var(--line);padding:7px 10px}.sys-table th{letter-spacing:.06em;color:var(--muted);font-size:12px;font-weight:700}:root{--accent-2:#5b8bff;--radius:14px;--shadow:0 1px 2px #141e3c0a, 0 8px 24px #141e3c0f;--shadow-lg:0 12px 40px #141e3c29}@media (prefers-color-scheme:dark){:root{--accent-2:#9db2ff;--shadow:0 1px 2px #0000004d, 0 8px 24px #00000059;--shadow-lg:0 16px 48px #0000008c}}body{background:radial-gradient(1100px 460px at 50% -220px, var(--accent-soft), transparent 70%), var(--bg);-webkit-font-smoothing:antialiased}.mono{font-variant-numeric:tabular-nums}.topbar{z-index:20;background:color-mix(in srgb, var(--surface) 86%, transparent);-webkit-backdrop-filter:saturate(160%)blur(12px);border-bottom-color:color-mix(in srgb, var(--line) 70%, transparent);position:sticky;top:0}.topbar-inner{padding:10px 20px 0}.brand{letter-spacing:-.01em;align-items:center;gap:8px;display:inline-flex}.brand:before{content:"AI";background:linear-gradient(135deg, var(--accent), var(--accent-2));color:#fff;letter-spacing:0;border-radius:8px;place-items:center;width:26px;height:26px;font-size:12px;font-weight:800;display:inline-grid}.nav{scrollbar-width:none;gap:4px;margin-top:6px;padding-bottom:8px;overflow-x:auto}.nav::-webkit-scrollbar{display:none}.nav button{white-space:nowrap;border:none;border-radius:999px;padding:6px 14px;transition:background .12s,color .12s}.nav button.on{background:var(--accent-soft);color:var(--accent);border-bottom-color:#0000}.nav button:hover:not(.on){background:var(--bg);color:var(--ink)}.stage{padding:28px 20px 80px}.btn{background:linear-gradient(135deg, var(--accent), var(--accent-2));box-shadow:0 6px 16px color-mix(in srgb, var(--accent) 26%, transparent);border-radius:12px;transition:transform .12s,box-shadow .12s,background .12s}.btn:hover:not(:disabled){box-shadow:0 10px 22px color-mix(in srgb, var(--accent) 32%, transparent);transform:translateY(-1px)}.btn:active:not(:disabled){transform:translateY(0)}.btn.ghost{background:var(--surface);box-shadow:none}.btn.ghost:hover:not(:disabled){background:var(--accent-soft);box-shadow:none}.btn.sm{box-shadow:none;border-radius:9px}.btn.lg{border-radius:14px;padding:13px 26px;font-size:16px}input[type=text],input[type=date],input[type=datetime-local],input[type=search],input[type=email],input[type=password],input:not([type]),textarea,select{border-radius:10px;padding:9px 12px;transition:border-color .12s,box-shadow .12s}input:focus,textarea:focus,select:focus{border-color:var(--accent);box-shadow:0 0 0 3px color-mix(in srgb, var(--accent) 18%, transparent);outline:none}.auth-form input,.auth-form .form-row input{padding:12px 14px;font-size:15px}.auth-form .btn{padding:12px 20px;font-size:15px}.card,.tutor-panel,.cta-card,.feature,.offer-card,.wrong-item{border-radius:var(--radius);box-shadow:var(--shadow)}.cta-card{background:linear-gradient(135deg, var(--accent-soft), var(--surface))}.modal{box-shadow:var(--shadow-lg);border-radius:18px;padding:22px 24px 24px}.modal-backdrop{-webkit-backdrop-filter:blur(4px)}.opt{border-radius:12px}.dash-head h2{letter-spacing:-.01em;font-size:22px}.hero-wrap{flex-direction:column;gap:22px;display:flex}.hero{max-width:640px;padding:30px 0 4px}.hero-kicker{color:var(--accent);background:var(--accent-soft);border-radius:999px;margin-bottom:14px;padding:3px 12px;font-size:13px;font-weight:700;display:inline-block}.hero h1{letter-spacing:-.02em;margin:0 0 14px;font-size:clamp(30px,5vw,44px);line-height:1.2}.hero-accent{background:linear-gradient(135deg, var(--accent), var(--accent-2));color:#0000;-webkit-background-clip:text;background-clip:text}.hero-sub{color:var(--muted);max-width:34em;margin:0 0 22px;font-size:16px}.hero-cta{flex-wrap:wrap;gap:12px;display:flex}.hero-note{margin:12px 0 0}.feature-grid{grid-template-columns:repeat(3,1fr);gap:12px;display:grid}.feature{background:var(--surface);border:1px solid var(--line);flex-direction:column;gap:3px;padding:16px 18px;display:flex}.feature-icon{width:40px;height:40px;color:var(--accent);background:var(--accent-soft);border-radius:12px;place-items:center;margin-bottom:6px;display:inline-grid}.acct .btn,.hero-cta .btn{white-space:nowrap}@media (width<=720px){.feature-grid{grid-template-columns:1fr}.feature{flex-direction:row;align-items:center;gap:12px}.feature-icon{flex:none;margin:0}.feature b{flex:none;min-width:6.5em;display:block}.feature>b+span{display:block}.hero{padding-top:14px}.hero-cta{flex-direction:column}.hero-cta .btn{text-align:center;width:100%}}.offer-card{background:var(--surface);border:1px solid var(--line);justify-content:space-between;align-items:center;gap:12px;padding:16px 18px;display:flex}.offer-card.promo{border-color:color-mix(in srgb, var(--amber) 50%, transparent);background:linear-gradient(135deg, var(--amber-soft), var(--surface))}.offer-card.clickable{cursor:pointer;transition:transform .15s,box-shadow .15s}.offer-card.clickable:hover,.offer-card.clickable:focus-visible{box-shadow:var(--shadow-lg,var(--shadow));outline:none;transform:translateY(-1px)}.offer-side{flex-wrap:wrap;justify-content:flex-end;align-items:center;gap:14px;display:flex}.offer-title{font-size:15px;font-weight:700}.offer-price,.pack-price-col{align-items:baseline;gap:8px;display:flex}.pack-price-col{flex-direction:column;align-items:flex-end;gap:0;line-height:1.15}.pack-price{color:var(--accent);letter-spacing:-.02em;font-size:28px;font-weight:800}.offer-card.promo .pack-price,.pack-card.promo .pack-price{color:var(--red)}.pack-original{color:var(--muted);font-size:14px}.pack-card{border-radius:14px;align-items:center}.pack-card.promo{border-color:color-mix(in srgb, var(--red) 40%, transparent);background:linear-gradient(135deg, var(--red-soft), var(--surface))}.pack-name{font-size:15px;font-weight:700}.promo-strip{color:var(--amber);background:var(--amber-soft);text-align:center;border-radius:10px;margin-top:10px;padding:8px 12px;font-size:13px}.promo-strip.urgent{color:var(--red);background:var(--red-soft)}.pay-type{border-radius:12px;padding:10px;font-weight:600}.pay-done-icon{background:var(--green-soft);width:56px;height:56px;color:var(--green);border-radius:50%;place-items:center;margin:0 auto;font-size:28px;font-weight:800;display:grid}.sys-row{grid-template-columns:1fr 1fr;gap:14px;display:grid}@media (width<=720px){.sys-row{grid-template-columns:1fr}}.tutor-thread:has(.tutor-lock){justify-content:safe center}.tutor-lock{margin:0 auto;padding:12px 0}.quiz-top{flex-wrap:wrap;gap:6px 12px}.hero-perks{color:var(--muted);flex-wrap:wrap;gap:6px 18px;margin:14px 0 0;padding:0;font-size:13.5px;list-style:none;display:flex}.hero-perks li:before{content:"✓";color:var(--green);margin-right:6px;font-weight:800}.brand{flex:none}.brand-divider{background:var(--line);flex:none;width:1px;height:18px;margin:0 2px}.course-switcher{flex:none;position:relative}.course-name{color:var(--ink);letter-spacing:-.01em;white-space:nowrap;font-size:16px;font-weight:700}.course-trigger{color:var(--ink);font:inherit;cursor:pointer;background:0 0;border:none;border-radius:9px;align-items:center;gap:4px;margin-left:-8px;padding:4px 6px 4px 8px;transition:background .12s;display:inline-flex}.course-trigger:hover,.course-trigger.open{background:var(--accent-soft)}.course-trigger:hover .course-name,.course-trigger.open .course-name{color:var(--accent)}.course-chevron{color:var(--muted);flex:none;transition:transform .15s}.course-trigger.open .course-chevron{color:var(--accent);transform:rotate(180deg)}.course-menu{z-index:30;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);min-width:280px;max-width:min(380px,100vw - 32px);box-shadow:var(--shadow-lg);outline:none;padding:6px;animation:.12s ease-out course-menu-in;position:absolute;top:calc(100% + 8px);left:-8px}@keyframes course-menu-in{0%{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}.course-menu-title{color:var(--muted);padding:6px 10px 4px;font-size:12px}.course-option{cursor:pointer;border-radius:10px;align-items:center;gap:10px;padding:8px 10px;display:flex}.course-option.active{background:var(--bg)}.course-option.selected .course-option-title{color:var(--accent)}.course-option-body{flex-direction:column;flex:1;min-width:0;line-height:1.4;display:flex}.course-option-title{font-size:14px;font-weight:600}.course-option-sub{color:var(--muted);text-overflow:ellipsis;white-space:nowrap;font-size:12px;overflow:hidden}.course-check{color:var(--accent);flex:none}.acct{flex:none}@media (width<=900px){.acct-email-full{display:none}.acct-email-short{display:inline}}@media (width<=720px){.brand{gap:0;font-size:0}.brand:before{font-size:12px}.brand-divider{display:none}.course-name{font-size:15px}.brand-row{flex-wrap:wrap;gap:6px 8px}.acct{gap:8px}.brand-row{position:relative}.course-switcher{position:static}.course-menu{min-width:0;max-width:none;top:calc(100% + 6px);left:0;right:0}}.seg{background:var(--bg);border-radius:12px;gap:4px;margin:0 0 14px;padding:4px;display:flex}.seg button{color:var(--muted);font:inherit;cursor:pointer;background:0 0;border:none;border-radius:9px;flex:1;padding:7px 10px;font-size:14px;font-weight:500;transition:background .12s,color .12s}.seg button.on{background:var(--surface);color:var(--ink);box-shadow:var(--shadow);font-weight:600}.acct-facts{grid-template-columns:auto 1fr;gap:6px 14px;margin:0 0 18px;font-size:14px;display:grid}.acct-facts dt{color:var(--muted)}.acct-facts dd{word-break:break-all;margin:0}.pwd-nudge{flex-wrap:wrap}.pwd-nudge-actions{flex:none;align-items:center;gap:12px;display:inline-flex}.pwd-card{border:1px solid var(--accent);background:var(--accent-soft);border-radius:var(--radius);margin:0 0 18px;padding:16px}.pwd-title{font-size:16px}.pwd-card+.acct-facts{margin-bottom:0}@media (width<=720px){.pwd-btn{padding-left:8px;padding-right:8px}.pwd-btn-text{display:none}}.fb-btn{white-space:nowrap;flex:none}@media (width<=720px){.fb-btn-text{display:none}}.fb-cats{flex-wrap:wrap;gap:6px;display:flex}.fb-cats button{border:1px solid var(--line);background:var(--surface);color:var(--muted);font:inherit;cursor:pointer;border-radius:999px;padding:5px 12px;font-size:13px;transition:background .12s,color .12s}.fb-cats button:hover{color:var(--ink);background:var(--bg)}.fb-cats button.on{color:var(--accent);background:var(--accent-soft);border-color:#0000;font-weight:600}.auth-form textarea{width:100%;font-size:15px;line-height:1.5}.fb-done{text-align:center;flex-direction:column;align-items:center;gap:8px;padding:8px 0 4px;display:flex}.fb-done-icon{background:var(--green-soft);width:48px;height:48px;color:var(--green);border-radius:50%;place-items:center;font-size:24px;font-weight:800;display:grid}.muted-link{color:var(--muted);font-size:13px}.tab-badge{background:var(--red);color:#fff;text-align:center;border-radius:999px;min-width:18px;margin-left:6px;padding:0 5px;font-size:11px;font-weight:700;line-height:18px;display:inline-block}.fb-seg{margin:0}.fb-table{white-space:normal}.fb-table td{vertical-align:top}.fb-time{white-space:nowrap}.fb-content{min-width:260px;max-width:520px}.fb-text{white-space:pre-wrap;word-break:break-word;line-height:1.5}.fb-ctx{margin-top:4px}.fb-id{opacity:.6;font-family:ui-monospace,monospace;font-size:11px}.fb-from{word-break:break-all;min-width:140px;line-height:1.5}.fb-actions{white-space:nowrap}.fb-resolved .fb-text,.fb-resolved .fb-from{color:var(--muted)}.redeem-input{box-sizing:border-box;text-align:center;letter-spacing:.12em;text-transform:uppercase;width:100%;padding:12px 10px;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:22px}.redeem-input::placeholder{letter-spacing:.12em;opacity:.4}.redeem-card{background:var(--surface);border:1px dashed var(--line);border-radius:var(--radius);cursor:pointer;justify-content:space-between;align-items:center;gap:12px;margin-top:14px;padding:14px 18px;display:flex}.redeem-card:hover,.redeem-card:focus-visible{border-color:var(--accent);outline:none}.redeem-card b{font-size:15px}.codes-fresh{background:var(--green-soft);border-radius:12px;margin-top:12px;padding:10px 12px}.codes-box{box-sizing:border-box;resize:vertical;letter-spacing:.06em;width:100%;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:14px;line-height:1.5}.code-cell{letter-spacing:.06em;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}