.kc-hub{--bg: #0A0915;--bg-soft: #0F0E1C;--surface-1: #15132480;--surface-1-solid:#151324;--surface-2: #1B1930;--surface-3: #23213C;--border: rgba(255,255,255,.08);--border-strong: rgba(255,255,255,.16);--text-1: #F6F5FB;--text-2: #B4B1C6;--text-3: #7B7891;--primary-900:#0E2A47;--primary-700:#12508B;--primary-500:#2E8FE8;--primary-400:#57A7EE;--primary-300:#8BC4F5;--primary-100:#D8ECFC;--secondary-900:#28125A;--secondary-700:#4E1FA6;--secondary-500:#8348EB;--secondary-300:#BBA1F4;--secondary-100:#EAE0FC;--grad-brand: linear-gradient(120deg,#4E9BFF 0%, #9857F2 100%);--grad-brand-soft: linear-gradient(120deg, rgba(78,155,255,.16) 0%, rgba(152,87,242,.16) 100%);--success:#33D399;--success-soft:rgba(51,211,153,.14);--error: #F1595F;--error-soft:rgba(241,89,95,.14);--alert: #F5A73C;--alert-soft:rgba(245,167,60,.14);--info: #4FB4FF;--info-soft:rgba(79,180,255,.14);--pink:#F16FA8;--yellow:#F6CB3E;--orange:#F2924A;--lime:#8FE05C;--teal:#33D3C0;--r-sm:8px;--r-md:14px;--r-lg:20px;--r-pill:999px;--font:"Inter",-apple-system,BlinkMacSystemFont,sans-serif;--shadow-1: 0 1px 2px rgba(0,0,0,.4);--shadow-2: 0 8px 24px rgba(0,0,0,.45);--shadow-glow: 0 0 0 1px rgba(152,87,242,.25), 0 8px 30px rgba(152,87,242,.18)}.kc-hub ::selection{background:var(--secondary-500);color:#fff}.kc-hub a{color:inherit;text-decoration:none}.kc-hub button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}.kc-hub input{font-family:inherit}.kc-hub ::-webkit-scrollbar{width:10px;height:10px}.kc-hub ::-webkit-scrollbar-thumb{background:var(--surface-3);border-radius:99px}.kc-hub .demo-switch{position:sticky;top:0;z-index:100;display:flex;align-items:center;gap:8px;padding:10px 20px;background:#0d0c18ee;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--border)}.kc-hub .demo-switch span{font-size:12px;color:var(--text-3);margin-right:6px;letter-spacing:.02em}.kc-hub .demo-tab{padding:7px 14px;border-radius:var(--r-pill);font-size:13px;font-weight:600;color:var(--text-2);border:1px solid var(--border)}.kc-hub .demo-tab.active{background:var(--grad-brand);color:#fff;border-color:transparent}.kc-hub .screen{display:none}.kc-hub .screen.active{display:block}.kc-hub .nav{position:sticky;top:41px;z-index:90;display:flex;align-items:center;justify-content:space-between;padding:14px 32px;background:#0a0915d9;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);border-bottom:1px solid var(--border)}.kc-hub .nav-left{display:flex;align-items:center;gap:36px}.kc-hub .logo{display:flex;align-items:center;gap:9px;font-weight:800;font-size:18px;letter-spacing:-.01em}.kc-hub .logo-mark{width:26px;height:26px;border-radius:8px;background:var(--grad-brand);display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:800;color:#fff}.kc-hub .nav-links{display:flex;gap:26px}.kc-hub .nav-links a{font-size:14px;font-weight:500;color:var(--text-2)}.kc-hub .nav-links a.current{color:var(--text-1)}.kc-hub .nav-right{display:flex;align-items:center;gap:14px}.kc-hub .icon-btn{width:36px;height:36px;border-radius:var(--r-pill);display:flex;align-items:center;justify-content:center;border:1px solid var(--border);color:var(--text-2)}.kc-hub .avatar{width:34px;height:34px;border-radius:50%;background:var(--grad-brand);display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:700;color:#fff;border:2px solid var(--border-strong)}.kc-hub .btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:11px 22px;border-radius:var(--r-pill);font-size:14px;font-weight:600;transition:transform .15s ease,box-shadow .15s ease,background .15s ease,border-color .15s ease;white-space:nowrap}.kc-hub .btn-primary{background:var(--grad-brand);color:#fff;box-shadow:0 4px 18px #8348eb59}.kc-hub .btn-primary:hover{transform:translateY(-1px);box-shadow:0 8px 26px #8348eb7a}.kc-hub .btn-secondary{background:var(--surface-2);color:var(--text-1);border:1px solid var(--border-strong)}.kc-hub .btn-secondary:hover{background:var(--surface-3)}.kc-hub .btn-ghost{color:var(--text-2);padding:11px 14px}.kc-hub .btn-ghost:hover{color:var(--text-1)}.kc-hub .btn-sm{padding:7px 14px;font-size:12.5px}.kc-hub .breadcrumb{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--text-3)}.kc-hub .breadcrumb a:hover{color:var(--text-2)}.kc-hub .breadcrumb .sep{opacity:.5}.kc-hub .breadcrumb .current{color:var(--text-1);font-weight:500}.kc-hub .wrap{max-width:1180px;margin:0 auto;padding:0 32px}.kc-hub .section{padding:40px 0}.kc-hub .chip{display:inline-flex;align-items:center;gap:6px;padding:5px 12px;border-radius:var(--r-pill);font-size:12px;font-weight:600;border:1px solid var(--border-strong);color:var(--text-2);background:var(--surface-2)}.kc-hub .chip-dot{width:6px;height:6px;border-radius:50%}.kc-hub .chip-domain{background:var(--info-soft);color:var(--info);border-color:transparent}.kc-hub .chip-domain.math{background:var(--secondary-500)22;color:var(--secondary-300)}.kc-hub .chip-time{background:var(--surface-2);color:var(--text-2);font-variant-numeric:tabular-nums}.kc-hub .badge{display:inline-flex;align-items:center;gap:5px;padding:3px 9px;border-radius:var(--r-pill);font-size:11px;font-weight:700;letter-spacing:.02em;text-transform:uppercase}.kc-hub .badge-success{background:var(--success-soft);color:var(--success)}.kc-hub .badge-info{background:var(--info-soft);color:var(--info)}.kc-hub .badge-neutral{background:var(--surface-3);color:var(--text-3)}.kc-hub .hero{border-radius:var(--r-lg);padding:44px;background:linear-gradient(135deg,var(--surface-1-solid) 0%,#181530 100%);border:1px solid var(--border);position:relative;overflow:hidden}.kc-hub .hero:after{content:"";position:absolute;top:0;right:0;bottom:0;left:0;background:radial-gradient(500px 260px at 85% 0%,rgba(152,87,242,.2),transparent 65%);pointer-events:none}.kc-hub .hero-eyebrow{display:flex;align-items:center;gap:8px;font-size:12.5px;font-weight:700;color:var(--secondary-300);text-transform:uppercase;letter-spacing:.06em;margin-bottom:14px}.kc-hub .hero-eyebrow .dot{width:6px;height:6px;border-radius:50%;background:var(--secondary-500)}.kc-hub .hero h1{font-size:38px;line-height:1.12;font-weight:800;letter-spacing:-.02em;max-width:640px}.kc-hub .hero p{margin-top:14px;font-size:16px;color:var(--text-2);max-width:520px;line-height:1.6}.kc-hub .hero-actions{display:flex;gap:12px;margin-top:26px;position:relative;z-index:1}.kc-hub .hero-stats{position:absolute;right:44px;top:44px;z-index:1;display:flex;flex-direction:column;align-items:center;gap:6px;background:var(--surface-2);border:1px solid var(--border-strong);border-radius:var(--r-lg);padding:18px 22px}.kc-hub .ring{position:relative;width:74px;height:74px}.kc-hub .ring svg{transform:rotate(-90deg)}.kc-hub .ring-track{stroke:var(--surface-3)}.kc-hub .ring-progress{stroke:url(#ringGrad);stroke-linecap:round}.kc-hub .ring-label{position:absolute;top:0;right:0;bottom:0;left:0;display:flex;align-items:center;justify-content:center;font-size:15px;font-weight:800;font-variant-numeric:tabular-nums}.kc-hub .hero-stats .cap{font-size:11px;color:var(--text-3);font-weight:600;text-transform:uppercase;letter-spacing:.04em}.kc-hub .grid-2{display:grid;grid-template-columns:1fr 1fr;gap:18px}.kc-hub .subject-card{border-radius:var(--r-lg);padding:26px;border:1px solid var(--border);background:var(--surface-1-solid);display:flex;flex-direction:column;gap:16px;transition:border-color .15s,transform .15s;position:relative}.kc-hub .subject-card:hover{border-color:var(--border-strong);transform:translateY(-2px)}.kc-hub .subject-card.math{background:linear-gradient(160deg,#171530,var(--surface-1-solid))}.kc-hub .subject-top{display:flex;align-items:flex-start;justify-content:space-between}.kc-hub .subject-icon{width:44px;height:44px;border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:19px;background:var(--grad-brand-soft);border:1px solid var(--border)}.kc-hub .subject-card h3{font-size:19px;font-weight:700;margin-top:2px}.kc-hub .subject-card .count{font-size:13px;color:var(--text-3);margin-top:2px}.kc-hub .bar{height:8px;border-radius:99px;background:var(--surface-3);overflow:hidden}.kc-hub .bar-fill{height:100%;border-radius:99px;background:var(--grad-brand)}.kc-hub .subject-meta{display:flex;align-items:center;justify-content:space-between;font-size:12.5px;color:var(--text-3)}.kc-hub .subject-foot{display:flex;align-items:center;justify-content:space-between;margin-top:4px}.kc-hub .explorer-head{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;margin-bottom:18px}.kc-hub .tabs{display:flex;padding:4px;background:var(--surface-2);border:1px solid var(--border);border-radius:var(--r-pill);gap:2px}.kc-hub .tab-item{padding:8px 16px;border-radius:var(--r-pill);font-size:13px;font-weight:600;color:var(--text-2)}.kc-hub .tab-item.active{background:var(--grad-brand);color:#fff}.kc-hub .search-box{display:flex;align-items:center;gap:8px;padding:9px 14px;border-radius:var(--r-pill);background:var(--surface-2);border:1px solid var(--border);min-width:230px}.kc-hub .search-box input{background:none;border:none;outline:none;color:var(--text-1);font-size:13px;width:100%}.kc-hub .search-box input::placeholder{color:var(--text-3)}.kc-hub .filter-row{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:22px}.kc-hub .filter-chip{padding:7px 14px;border-radius:var(--r-pill);border:1px solid var(--border-strong);font-size:12.5px;font-weight:600;color:var(--text-2);background:var(--surface-1);display:flex;align-items:center;gap:6px}.kc-hub .filter-chip.active{background:var(--secondary-500)26;border-color:var(--secondary-500);color:var(--secondary-300)}.kc-hub .filter-chip svg{width:12px;height:12px}.kc-hub .view-toggle{display:flex;border:1px solid var(--border);border-radius:var(--r-sm);overflow:hidden;margin-left:auto}.kc-hub .view-toggle button{padding:8px 10px;color:var(--text-3)}.kc-hub .view-toggle button.active{background:var(--surface-3);color:var(--text-1)}.kc-hub .tile-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.kc-hub .tile{border-radius:var(--r-md);padding:20px;background:var(--surface-1-solid);border:1px solid var(--border);display:flex;flex-direction:column;gap:12px;transition:border-color .15s,transform .15s,box-shadow .15s}.kc-hub .tile:hover{border-color:var(--border-strong);transform:translateY(-3px);box-shadow:var(--shadow-2)}.kc-hub .tile-top{display:flex;align-items:center;justify-content:space-between}.kc-hub .tile-icon{width:36px;height:36px;border-radius:10px;display:flex;align-items:center;justify-content:center;font-size:16px}.kc-hub .status-dot{width:20px;height:20px;border-radius:50%;display:flex;align-items:center;justify-content:center;border:2px solid var(--surface-3)}.kc-hub .status-dot.done{background:var(--success);border-color:var(--success)}.kc-hub .status-dot.progress{border-color:var(--info);background:conic-gradient(var(--info) 0 55%,transparent 55% 100%)}.kc-hub .status-dot.todo{border-color:var(--border-strong)}.kc-hub .tile h4{font-size:15.5px;font-weight:700;letter-spacing:-.005em}.kc-hub .tile p{font-size:13px;color:var(--text-2);line-height:1.5;min-height:38px}.kc-hub .tile-foot{display:flex;align-items:center;justify-content:space-between;margin-top:2px}.kc-hub .tile-meta{display:flex;gap:6px;align-items:center}.kc-hub .tile-link{font-size:13px;font-weight:700;color:var(--primary-400);display:flex;align-items:center;gap:4px}.kc-hub .section-head{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:18px}.kc-hub .section-head h2{font-size:20px;font-weight:700;letter-spacing:-.01em}.kc-hub .section-head .sub{font-size:13px;color:var(--text-3)}.kc-hub .concept-layout{display:grid;grid-template-columns:1fr 260px;gap:40px;align-items:start}.kc-hub .concept-main{display:flex;flex-direction:column;gap:36px}.kc-hub .concept-header{display:flex;flex-direction:column;gap:14px;padding-top:10px}.kc-hub .concept-tags{display:flex;gap:8px;align-items:center}.kc-hub .concept-header h1{font-size:34px;font-weight:800;letter-spacing:-.02em}.kc-hub .concept-header .promise{font-size:15.5px;color:var(--text-2);max-width:600px;line-height:1.55}.kc-hub .concept-header-meta{display:flex;gap:10px;margin-top:2px}.kc-hub .concept-header-actions{display:flex;gap:12px;margin-top:8px}.kc-hub .card{background:var(--surface-1-solid);border:1px solid var(--border);border-radius:var(--r-lg);padding:26px}.kc-hub .card-head{display:flex;align-items:center;justify-content:between;gap:10px;margin-bottom:16px}.kc-hub .card-head h3{font-size:15px;font-weight:700;display:flex;align-items:center;gap:8px}.kc-hub .card-head h3 .n{width:22px;height:22px;border-radius:6px;background:var(--grad-brand-soft);color:var(--secondary-300);display:flex;align-items:center;justify-content:center;font-size:11.5px;font-weight:800}.kc-hub .snapshot-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px 26px}.kc-hub .snap-item .label{font-size:11px;text-transform:uppercase;letter-spacing:.06em;color:var(--text-3);font-weight:700;margin-bottom:6px}.kc-hub .snap-item .val{font-size:14px;color:var(--text-1);line-height:1.55}.kc-hub .snap-item.full{grid-column:1/-1}.kc-hub .formula-pill{display:inline-block;background:var(--surface-2);border:1px solid var(--border-strong);padding:8px 14px;border-radius:var(--r-sm);font-size:14.5px;font-weight:600;color:var(--primary-300)}.kc-hub .visual-toggle{display:flex;gap:2px;background:var(--surface-2);border:1px solid var(--border);border-radius:var(--r-pill);padding:3px;width:fit-content;margin-bottom:18px}.kc-hub .visual-toggle button{padding:6px 14px;border-radius:var(--r-pill);font-size:12.5px;font-weight:600;color:var(--text-2)}.kc-hub .visual-toggle button.active{background:var(--surface-3);color:var(--text-1)}.kc-hub .graph-wrap{background:var(--surface-2);border:1px solid var(--border);border-radius:var(--r-md);padding:20px}.kc-hub .pattern-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.kc-hub .pattern-card{background:var(--surface-2);border:1px solid var(--border);border-radius:var(--r-md);padding:16px;display:flex;flex-direction:column;gap:8px}.kc-hub .pattern-card .tag{font-size:11px;font-weight:700;color:var(--info);text-transform:uppercase;letter-spacing:.04em}.kc-hub .pattern-card h4{font-size:14px;font-weight:700}.kc-hub .pattern-card p{font-size:12.5px;color:var(--text-2);line-height:1.5}.kc-hub .pattern-card .clue{font-size:11.5px;color:var(--alert);font-weight:600;margin-top:2px}.kc-hub .steps{display:flex;flex-direction:column;gap:8px}.kc-hub .step{border:1px solid var(--border);border-radius:var(--r-md);overflow:hidden;background:var(--surface-2)}.kc-hub .step-head{display:flex;align-items:center;gap:12px;padding:14px 16px}.kc-hub .step-num{width:26px;height:26px;border-radius:50%;background:var(--surface-3);display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:800;flex-shrink:0}.kc-hub .step.open .step-num{background:var(--grad-brand);color:#fff}.kc-hub .step-head span{font-size:13.5px;font-weight:600;flex:1}.kc-hub .step-head svg{transition:transform .2s;color:var(--text-3)}.kc-hub .step.open .step-head svg{transform:rotate(180deg)}.kc-hub .step-body{max-height:0;overflow:hidden;transition:max-height .25s ease}.kc-hub .step.open .step-body{max-height:200px}.kc-hub .step-body-in{padding:0 16px 16px 54px;font-size:13px;color:var(--text-2);line-height:1.6}.kc-hub .qcard{display:flex;flex-direction:column;gap:16px}.kc-hub .qtext{font-size:14.5px;line-height:1.6}.kc-hub .qtext b{color:var(--text-1)}.kc-hub .options{display:flex;flex-direction:column;gap:10px}.kc-hub .option{display:flex;align-items:center;gap:14px;padding:13px 16px;border-radius:var(--r-md);border:1px solid var(--border-strong);background:var(--surface-2);transition:.15s;text-align:left}.kc-hub .option:hover{border-color:var(--primary-400)}.kc-hub .bubble{width:26px;height:26px;border-radius:50%;border:2px solid var(--border-strong);flex-shrink:0;display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:800;color:var(--text-3)}.kc-hub .option-label{font-size:13.5px;color:var(--text-1)}.kc-hub .option.correct{border-color:var(--success);background:var(--success-soft)}.kc-hub .option.correct .bubble{background:var(--success);border-color:var(--success);color:#08160f}.kc-hub .option.wrong{border-color:var(--error);background:var(--error-soft)}.kc-hub .option.wrong .bubble{background:var(--error);border-color:var(--error);color:#1a0808}.kc-hub .feedback{display:none;border-radius:var(--r-md);padding:16px 18px;font-size:13.5px;line-height:1.6;border:1px solid var(--border)}.kc-hub .feedback.show{display:block}.kc-hub .feedback.success{background:var(--success-soft);border-color:var(--success);color:#dffbee}.kc-hub .feedback.error{background:var(--error-soft);border-color:var(--error);color:#fde3e4}.kc-hub .feedback .ftitle{font-weight:800;margin-bottom:4px;display:flex;align-items:center;gap:8px}.kc-hub .trap-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.kc-hub .trap-card{background:var(--surface-2);border:1px solid var(--border);border-radius:var(--r-md);padding:16px}.kc-hub .trap-card .k{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;margin-bottom:6px}.kc-hub .trap-card p{font-size:12.5px;color:var(--text-2);line-height:1.5}.kc-hub .trap-card.t1 .k{color:var(--alert)}.kc-hub .trap-card.t2 .k{color:var(--error)}.kc-hub .trap-card.t3 .k{color:var(--success)}.kc-hub .video-wrap{display:flex;gap:20px}.kc-hub .video-thumb{width:230px;height:130px;flex-shrink:0;border-radius:var(--r-md);background:linear-gradient(135deg,var(--secondary-900),var(--primary-900));display:flex;align-items:center;justify-content:center;position:relative;border:1px solid var(--border-strong)}.kc-hub .play-btn{width:44px;height:44px;border-radius:50%;background:#ffffff24;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);display:flex;align-items:center;justify-content:center;border:1px solid rgba(255,255,255,.3)}.kc-hub .video-info h4{font-size:15px;font-weight:700;margin-bottom:6px}.kc-hub .video-info p{font-size:13px;color:var(--text-2);margin-bottom:10px}.kc-hub .timestamps{display:flex;gap:8px;flex-wrap:wrap}.kc-hub .related-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.kc-hub .rel-card{background:var(--surface-2);border:1px solid var(--border);border-radius:var(--r-md);padding:16px;display:flex;flex-direction:column;gap:8px}.kc-hub .rel-card .k{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.04em;color:var(--text-3)}.kc-hub .rel-card h4{font-size:14px;font-weight:700}.kc-hub .rel-card .go{font-size:12px;font-weight:700;color:var(--primary-400);margin-top:auto}.kc-hub .rail{position:sticky;top:130px;display:flex;flex-direction:column;gap:18px}.kc-hub .toc{background:var(--surface-1-solid);border:1px solid var(--border);border-radius:var(--r-lg);padding:18px}.kc-hub .toc .t{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--text-3);margin-bottom:12px}.kc-hub .toc-item{display:flex;align-items:center;gap:10px;font-size:13px;color:var(--text-2);border-left:2px solid transparent;padding:8px 0 8px 10px;margin-left:-10px}.kc-hub .toc-item.active{color:var(--text-1);font-weight:600;border-left-color:var(--secondary-500)}.kc-hub .toc-item .dot{width:5px;height:5px;border-radius:50%;background:var(--text-3)}.kc-hub .toc-item.active .dot{background:var(--secondary-500)}.kc-hub .progress-card{background:linear-gradient(160deg,#181530,var(--surface-1-solid));border:1px solid var(--border);border-radius:var(--r-lg);padding:18px;text-align:center}.kc-hub .progress-card .ring{margin:0 auto 10px}.kc-hub .progress-card p{font-size:12px;color:var(--text-3);line-height:1.5}.kc-hub .mobile-bar{display:none}.kc-hub .pn{display:flex;justify-content:space-between;border-top:1px solid var(--border);padding-top:24px;margin-top:8px}.kc-hub .pn a{font-size:13px;color:var(--text-2);display:flex;align-items:center;gap:8px}.kc-hub .pn a:hover{color:var(--text-1)}.kc-hub .pn .lbl{font-size:10.5px;text-transform:uppercase;color:var(--text-3);letter-spacing:.05em;display:block;margin-bottom:3px}@media(max-width:900px){.kc-hub .tile-grid{grid-template-columns:1fr 1fr}.kc-hub .grid-2,.kc-hub .concept-layout{grid-template-columns:1fr}.kc-hub .rail{display:none}.kc-hub .pattern-grid,.kc-hub .trap-grid,.kc-hub .related-grid{grid-template-columns:1fr}.kc-hub .nav-links{display:none}.kc-hub .hero h1{font-size:28px}.kc-hub .hero-stats{position:static;margin-top:20px;flex-direction:row;justify-content:center}}@media(max-width:600px){.kc-hub .tile-grid{grid-template-columns:1fr}.kc-hub .wrap{padding:0 16px}}.kc-hub .demo-switch{display:none}.kc-hub .nav{top:0}.kc-hub .tile{color:inherit}.kc-hub .option:disabled{cursor:default}.kc-hub .vis-note{font-size:12.5px;color:var(--text-3);margin-top:10px;line-height:1.5}.kc-hub .vis-note b{font-weight:600}.kc-hub .annot-legend{display:flex;gap:14px;margin-bottom:16px;flex-wrap:wrap;font-size:11.5px;font-weight:700}.kc-hub .annot-legend span{display:flex;align-items:center;gap:6px}.kc-hub .annot-legend i{width:10px;height:10px;border-radius:3px;display:inline-block}.kc-hub .annot-text{font-size:15px;line-height:2;color:var(--text-2);margin:0}.kc-hub .annot-text mark{color:var(--text-1);padding:2px 4px;border-radius:4px}.kc-hub .gram-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}.kc-hub .gram-card{border-radius:var(--r-md);padding:20px;border:1px solid}.kc-hub .gram-card.bad{background:var(--error-soft);border-color:var(--error)}.kc-hub .gram-card.good{background:var(--success-soft);border-color:var(--success)}.kc-hub .gram-card p{font-size:14.5px;line-height:1.7;margin:0}.kc-hub .gram-card.bad p{color:#fde3e4}.kc-hub .gram-card.good p{color:#dffbee}.kc-hub .gram-k{font-size:11px;font-weight:800;text-transform:uppercase;letter-spacing:.04em;margin-bottom:10px}.kc-hub .gram-mark{padding:1px 6px;border-radius:4px;font-weight:800;margin:0 2px;font-style:normal}.kc-hub .gram-mark.bad{background:var(--error);color:#1a0808}.kc-hub .gram-mark.good{background:var(--success);color:#08160f}.kc-hub .bar-row{display:grid;grid-template-columns:110px 1fr 40px;gap:10px;align-items:center;margin-bottom:12px}.kc-hub .bar-row span{font-size:12.5px;color:var(--text-2)}.kc-hub .bar-row i{display:block;height:18px;border-radius:5px;background:linear-gradient(90deg,#4e9bff,#9857f2)}.kc-hub .bar-row b{font-size:12.5px;font-variant-numeric:tabular-nums}.kc-hub .rel-card{color:inherit}.kc-hub .toc-item{cursor:pointer}.kc-hub .concept-header-meta .chip{white-space:nowrap}@media(max-width:900px){.kc-hub .gram-grid{grid-template-columns:1fr}}.kc-hub .toolkit-banner{position:relative;overflow:hidden;padding:24px;border-radius:var(--r-lg);background:linear-gradient(125deg,#4e9bff21,#9857f221);border:1px solid rgba(139,196,245,.18)}.kc-hub .toolkit-banner:after{content:"";position:absolute;width:220px;height:220px;border-radius:50%;right:-80px;top:-110px;background:#9857f21f;filter:blur(2px)}.kc-hub .toolkit-top{display:flex;justify-content:space-between;gap:18px;align-items:flex-start;position:relative;z-index:1}.kc-hub .toolkit-kicker{font-size:11px;font-weight:800;text-transform:uppercase;letter-spacing:.08em;color:var(--primary-300);margin-bottom:8px}.kc-hub .toolkit-banner h2{font-size:20px;letter-spacing:-.01em;margin-bottom:7px}.kc-hub .toolkit-banner p{font-size:13.5px;line-height:1.55;color:var(--text-2);max-width:620px}.kc-hub .resource-count{display:flex;align-items:center;gap:7px;white-space:nowrap;font-size:11.5px;font-weight:700;color:var(--success);background:var(--success-soft);border:1px solid rgba(51,211,153,.25);padding:7px 11px;border-radius:var(--r-pill)}.kc-hub .resource-count i{display:block;width:7px;height:7px;border-radius:50%;background:var(--success)}.kc-hub .toolkit-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:18px;position:relative;z-index:1}.kc-hub .audio-card{padding:16px;border-radius:var(--r-md);background:#151324c7;border:1px solid var(--border-strong)}.kc-hub .audio-card-top{display:flex;align-items:center;gap:12px;margin-bottom:13px}.kc-hub .audio-play{width:42px;height:42px;border-radius:50%;display:flex;align-items:center;justify-content:center;background:var(--grad-brand);box-shadow:0 6px 18px #8348eb4d;flex-shrink:0}.kc-hub .audio-copy{min-width:0;flex:1}.kc-hub .audio-copy h4{font-size:13.5px;margin-bottom:3px}.kc-hub .audio-copy p{font-size:11.5px;color:var(--text-3);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.kc-hub .audio-time{font-size:11.5px;font-variant-numeric:tabular-nums;color:var(--text-2)}.kc-hub .audio-track{height:4px;border-radius:99px;background:var(--surface-3);overflow:hidden}.kc-hub .audio-track i{display:block;height:100%;width:0;background:var(--grad-brand);transition:width .2s}.kc-hub .audio-card.playing .audio-track i{animation:kc-audioDemo 18s linear forwards}.kc-hub .audio-card.playing .audio-play{animation:kc-pulsePlay 1.6s ease-in-out infinite}.kc-hub .audio-actions{display:flex;align-items:center;justify-content:space-between;margin-top:10px}.kc-hub .audio-actions button{font-size:11.5px;font-weight:700;color:var(--primary-300)}.kc-hub .ai-note{font-size:10.5px!important;color:var(--text-3)!important}.kc-hub .ai-note:before{content:"✦ ";color:var(--secondary-300)}.kc-hub .mindmap{display:grid;grid-template-columns:1fr 1.1fr 1fr;gap:14px;align-items:center;padding:8px 0}.kc-hub .mind-col{display:flex;flex-direction:column;gap:10px}.kc-hub .mind-node{padding:13px 14px;border-radius:var(--r-md);border:1px solid var(--border);background:var(--surface-2);font-size:12.5px;line-height:1.45;color:var(--text-2)}.kc-hub .mind-node b{display:block;color:var(--text-1);font-size:12px;margin-bottom:3px}.kc-hub .mind-core{text-align:center;padding:22px 16px;background:var(--grad-brand-soft);border:1px solid rgba(152,87,242,.32);border-radius:var(--r-lg)}.kc-hub .mind-core .symbol{font-size:27px;margin-bottom:7px}.kc-hub .mind-core h4{font-size:14px}.kc-hub .mind-core p{font-size:11.5px;color:var(--text-2);margin-top:5px;line-height:1.45}.kc-hub .equiv-flow{display:grid;grid-template-columns:1fr auto 1fr;gap:14px;align-items:center}.kc-hub .equiv-box{padding:22px 18px;text-align:center;border-radius:var(--r-md);border:1px solid var(--border-strong);background:var(--surface-2)}.kc-hub .equiv-box .form{font-size:20px;font-weight:800;color:var(--text-1);letter-spacing:.01em}.kc-hub .equiv-box small{display:block;margin-top:7px;color:var(--text-3);font-size:11px}.kc-hub .equiv-arrow{font-size:24px;color:var(--secondary-300)}.kc-hub .identity-row{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:12px}.kc-hub .identity{padding:12px 14px;border-radius:var(--r-sm);font-size:12.5px;line-height:1.5;background:var(--grad-brand-soft);border:1px solid rgba(152,87,242,.2);color:var(--text-2)}.kc-hub .identity b{color:var(--primary-300)}.kc-hub .flashcard-toolbar{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px}.kc-hub .flash-progress{font-size:12px;color:var(--text-3);font-variant-numeric:tabular-nums}.kc-hub .flash-scene{perspective:900px;height:230px}.kc-hub .flash-card{height:100%;position:relative;transform-style:preserve-3d;transition:transform .45s;cursor:pointer}.kc-hub .flash-card.flipped{transform:rotateY(180deg)}.kc-hub .flash-face{position:absolute;top:0;right:0;bottom:0;left:0;backface-visibility:hidden;border-radius:var(--r-lg);border:1px solid var(--border-strong);display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:30px;background:linear-gradient(145deg,var(--surface-2),#1c1934)}.kc-hub .flash-face.back{transform:rotateY(180deg);background:linear-gradient(145deg,#171b32,#1c1836)}.kc-hub .flash-label{font-size:10.5px;font-weight:800;text-transform:uppercase;letter-spacing:.08em;color:var(--secondary-300);margin-bottom:14px}.kc-hub .flash-face h4{font-size:19px;line-height:1.35;max-width:520px}.kc-hub .flash-face p{font-size:14px;color:var(--text-2);line-height:1.65;max-width:560px}.kc-hub .flash-hint{position:absolute;bottom:15px;font-size:10.5px;color:var(--text-3)}.kc-hub .flash-nav{display:flex;justify-content:center;align-items:center;gap:10px;margin-top:14px}.kc-hub .flash-nav .btn{min-width:92px}.kc-hub .quiz-intro{display:flex;justify-content:space-between;gap:16px;align-items:center;margin-bottom:18px}.kc-hub .quiz-intro p{font-size:13px;line-height:1.55;color:var(--text-2)}.kc-hub .quiz-dots{display:flex;gap:6px}.kc-hub .quiz-dot{width:8px;height:8px;border-radius:50%;background:var(--surface-3)}.kc-hub .quiz-dot.active{background:var(--primary-400)}.kc-hub .quiz-dot.done{background:var(--success)}.kc-hub .quiz-result{text-align:center;padding:24px;border-radius:var(--r-md);background:var(--grad-brand-soft);border:1px solid rgba(152,87,242,.3)}.kc-hub .quiz-score{font-size:36px;font-weight:800;letter-spacing:-.03em}.kc-hub .quiz-result p{font-size:13px;color:var(--text-2);margin:8px auto 16px;max-width:480px;line-height:1.55}.kc-hub .downloads-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}.kc-hub .download-item{display:flex;align-items:center;gap:13px;padding:15px;border:1px solid var(--border);border-radius:var(--r-md);background:var(--surface-2)}.kc-hub .download-icon{width:38px;height:38px;border-radius:10px;display:flex;align-items:center;justify-content:center;background:var(--grad-brand-soft);color:var(--primary-300);font-size:17px}.kc-hub .download-copy{flex:1}.kc-hub .download-copy h4{font-size:13px;margin-bottom:3px}.kc-hub .download-copy p{font-size:11px;color:var(--text-3)}.kc-hub .download-item button{font-size:11.5px;font-weight:700;color:var(--primary-300)}.kc-hub .transcript-box{border:1px solid var(--border);border-radius:var(--r-md);overflow:hidden;background:var(--surface-2)}.kc-hub .transcript-head{width:100%;display:flex;align-items:center;gap:12px;padding:15px 16px;text-align:left}.kc-hub .transcript-head span:nth-child(2){flex:1;font-size:13px;font-weight:700}.kc-hub .transcript-head small{font-size:10.5px;color:var(--text-3)}.kc-hub .transcript-body{display:none;padding:0 16px 18px}.kc-hub .transcript-body.open{display:block}.kc-hub .transcript-body p{font-size:12.5px;color:var(--text-2);line-height:1.7;margin-top:12px}.kc-hub .transcript-stamp{color:var(--primary-300);font-weight:700;margin-right:8px}.kc-hub .ask-card{display:flex;gap:18px;align-items:center;padding:20px;border-radius:var(--r-md);background:linear-gradient(120deg,#4e9bff1c,#9857f21f);border:1px solid rgba(139,196,245,.18)}.kc-hub .ask-mark{width:48px;height:48px;border-radius:14px;background:var(--grad-brand);display:flex;align-items:center;justify-content:center;font-size:21px;flex-shrink:0}.kc-hub .ask-copy{flex:1}.kc-hub .ask-copy h4{font-size:14px;margin-bottom:5px}.kc-hub .ask-copy p{font-size:12px;color:var(--text-2);line-height:1.5}.kc-hub .toast{position:fixed;left:50%;bottom:28px;transform:translate(-50%,20px);opacity:0;pointer-events:none;z-index:200;padding:12px 18px;border-radius:var(--r-pill);background:#29263f;border:1px solid var(--border-strong);box-shadow:var(--shadow-2);font-size:12.5px;color:var(--text-1);transition:.2s}.kc-hub .toast.show{opacity:1;transform:translate(-50%)}@media print{.kc-hub .nav,.kc-hub .rail,.kc-hub .concept-header-actions,.kc-hub .toolkit-banner,.kc-hub .mobile-bar,.kc-hub .pn,.kc-hub .btn,.kc-hub .toast{display:none!important}.kc-hub .concept-layout{display:block}.kc-hub .concept-main{gap:18px}.kc-hub .card{break-inside:avoid;background:#fff!important;color:#111;border:1px solid #ddd}.kc-hub .card *{color:#111!important}.kc-hub .wrap{max-width:none}.kc-hub .section{padding:12px 0}}@media(max-width:760px){.kc-hub .toolkit-grid,.kc-hub .downloads-grid,.kc-hub .identity-row{grid-template-columns:1fr}.kc-hub .toolkit-top,.kc-hub .quiz-intro,.kc-hub .ask-card{align-items:flex-start;flex-direction:column}.kc-hub .resource-count{align-self:flex-start}.kc-hub .mindmap{grid-template-columns:1fr}.kc-hub .mind-core{order:-1}.kc-hub .equiv-flow{grid-template-columns:1fr}.kc-hub .equiv-arrow{transform:rotate(90deg);text-align:center}.kc-hub .flash-scene{height:280px}.kc-hub .video-wrap{flex-direction:column}.kc-hub .video-thumb{width:100%}.kc-hub .concept-header-actions,.kc-hub .concept-header-meta{flex-wrap:wrap}}@keyframes kc-audioDemo{0%{width:0}to{width:100%}}@keyframes kc-pulsePlay{50%{box-shadow:0 0 0 7px #8348eb26}}.kc-hub,.kc-hub *{box-sizing:border-box}.kc-hub{margin:0;padding:0;background:var(--bg);color:var(--text-1);font-family:var(--font);-webkit-font-smoothing:antialiased}html:has(.kc-hub),body:has(.kc-hub){overflow-x:clip}.kc-hub{text-align:left;line-height:normal}.kc-hub *,.kc-hub *:before,.kc-hub *:after{box-sizing:border-box;margin:0;padding:0}.kc-hub ul,.kc-hub ol{list-style:none}.kc-hub .card-head h2{font-size:15px;font-weight:700;display:flex;align-items:center;gap:8px}.kc-hub .card-head h2 .n{width:22px;height:22px;border-radius:6px;background:var(--grad-brand-soft);color:var(--secondary-300);display:flex;align-items:center;justify-content:center;font-size:11.5px;font-weight:800;flex:none}.kc-hub .kc-sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.kc-hub a:focus-visible,.kc-hub button:focus-visible,.kc-hub input:focus-visible,.kc-hub [tabindex]:focus-visible{outline:3px solid var(--secondary-300);outline-offset:2px;border-radius:var(--r-sm)}.kc-hub .btn{min-height:44px;display:inline-flex;align-items:center;justify-content:center}.kc-hub .btn-sm{min-height:40px}.kc-hub .step-body{display:grid;grid-template-rows:0fr;max-height:none;overflow:hidden;transition:grid-template-rows .25s ease}.kc-hub .step.open .step-body{grid-template-rows:1fr;max-height:none}.kc-hub .step-body>*{min-height:0}.kc-hub .step-body-in{padding-bottom:0;transition:padding-bottom .25s ease}.kc-hub .step.open .step-body-in{padding-bottom:16px}.kc-hub .kc-toc-toggle{display:block;width:100%;text-align:left;background:none;border:0;padding:0;cursor:default;font:inherit;font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--text-3);margin-bottom:12px}@media(max-width:900px){.kc-hub .rail{display:flex;position:static;order:-1;margin-bottom:18px}.kc-hub .rail .progress-card{display:none}.kc-hub .kc-toc-toggle{cursor:pointer;margin-bottom:0}.kc-hub .kc-toc-toggle:after{content:" ▾"}.kc-hub .toc.open .kc-toc-toggle:after{content:" ▴"}.kc-hub .kc-toc-items{display:none}.kc-hub .toc.open .kc-toc-items{display:block;margin-top:12px}}@media(max-width:600px){.kc-hub .mobile-bar{display:flex;gap:10px;position:fixed;left:0;right:0;bottom:0;z-index:40;padding:10px 16px calc(10px + env(safe-area-inset-bottom));background:var(--surface-1-solid);border-top:1px solid var(--border-strong)}.kc-hub .mobile-bar .btn{flex:1}.kc-hub .concept-layout{padding-bottom:72px}}.kc-hub .flash-card.kc-no-flip{transform-style:flat;transition:none}.kc-hub .flash-card.kc-no-flip.flipped{transform:none}.kc-hub .flash-card.kc-no-flip .flash-face{backface-visibility:visible;transition:opacity .12s linear}.kc-hub .flash-card.kc-no-flip .flash-face.back{transform:none;opacity:0}.kc-hub .flash-card.kc-no-flip.flipped .flash-face.front{opacity:0}.kc-hub .flash-card.kc-no-flip.flipped .flash-face.back{opacity:1}@media(prefers-reduced-motion:reduce){.kc-hub *,.kc-hub *:before,.kc-hub *:after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}.kc-hub .btn:hover,.kc-hub .tile:hover{transform:none}}.kc-hub .tile h3{font-size:15.5px;font-weight:700;letter-spacing:-.005em}.kc-hub .pattern-card h3{font-size:14px;font-weight:700}.kc-hub .video-info h3{font-size:15px;font-weight:700;margin-bottom:6px}.kc-hub .rel-card h3{font-size:14px;font-weight:700}.kc-hub .audio-copy h3{font-size:13.5px;margin-bottom:3px}.kc-hub .mind-core h3{font-size:14px}.kc-hub .flash-face h3{font-size:19px;line-height:1.35;max-width:520px}.kc-hub .download-item h3{font-size:13px;margin-bottom:3px}.kc-hub .ask-copy h3{font-size:14px;margin-bottom:5px}.kc-hub .subject-card h2{font-size:18px;font-weight:700;letter-spacing:-.01em}.kc-hub button.flash-card{display:block;width:100%;padding:0;border:0;background:none;font:inherit;color:inherit;text-align:inherit}.kc-hub .audio-card.playing .audio-track i,.kc-hub input.audio-track{animation:none}.kc-hub input.audio-track{-webkit-appearance:none;-moz-appearance:none;appearance:none;width:100%;height:4px;margin:10px 0 0;padding:0;border-radius:99px;background:var(--surface-3);cursor:pointer}.kc-hub input.audio-track::-webkit-slider-thumb{-webkit-appearance:none;-moz-appearance:none;appearance:none;width:12px;height:12px;border:0;border-radius:50%;background:var(--secondary-300)}.kc-hub input.audio-track::-moz-range-thumb{width:12px;height:12px;border:0;border-radius:50%;background:var(--secondary-300)}.kc-hub input.audio-track::-moz-range-track{height:4px;border-radius:99px;background:var(--surface-3)}.kc-hub .audio-card-top{flex-wrap:wrap}.kc-hub .audio-card-top input.audio-track{flex:1 0 100%;order:10}.kc-hub .audio-time{font-variant-numeric:tabular-nums;white-space:nowrap}