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120px);padding:30px 0 32px;display:grid}.hero-copy h1{letter-spacing:0;max-width:700px;margin:0;font-size:clamp(52px,5.8vw,86px);line-height:1.12}.headline-line{white-space:nowrap;padding-bottom:.08em;line-height:1.04;display:block}.stage-column{min-width:0}.math-stage{background:0 0;border-radius:0;min-height:min(560px,62vh);position:relative;overflow:hidden}.math-stage canvas{cursor:crosshair;width:100%;height:100%;position:absolute;inset:0;-webkit-mask-image:radial-gradient(#000 56%,#000000d6 76%,#0000 100%);mask-image:radial-gradient(#000 56%,#000000d6 76%,#0000 100%)}.module-section{padding:24px 0 34px}.section-head{justify-content:space-between;align-items:end;gap:24px;margin-bottom:18px;display:flex}.section-head--count-only{justify-content:flex-end}.section-head h2{letter-spacing:0;margin:0;font-size:clamp(28px,3vw,44px);line-height:1.06}.section-head p{max-width:760px;color:var(--muted);margin:12px 0 0;font-size:15px;line-height:1.65}.section-count{border:1px solid rgba(var(--accent-rgb), .28);min-height:42px;color:var(--accent-2);background:rgba(var(--accent-rgb), .09);white-space:nowrap;border-radius:8px;justify-content:center;padding:0 14px;font-weight:900}.module-grid{grid-template-columns:repeat(3,minmax(230px,1fr));gap:14px;display:grid}.module-card{border:1px solid var(--line);background:#0a141db8;border-radius:8px;transition:transform .18s,border-color .18s,background .18s}.module-card:hover{border-color:rgba(var(--module-rgb), .42);background:#0e1c26f5;transform:translateY(-4px)}.module-link{z-index:1;width:100%;min-height:230px;color:inherit;grid-template-rows:auto 1fr auto;grid-template-columns:auto auto 1fr;gap:11px;padding:18px;display:grid;position:relative}.card-index{color:#ecf7fb6b;font-variant-numeric:tabular-nums;font-size:12px;font-weight:900}.card-icon{background:rgba(var(--module-rgb), .1);width:36px;height:36px;color:var(--module-color);border:1px solid;border-radius:8px;grid-column:2;justify-content:center;align-items:center;display:inline-flex}.card-body{flex-direction:column;grid-column:1/-1;align-self:end;gap:10px;display:flex}.card-category{color:var(--muted);font-size:12px;font-weight:850}.card-body strong{color:#f5fbfd;font-size:clamp(20px,1.7vw,27px);line-height:1.18}.card-body span:last-child{color:#a9bdc8;font-size:13px;line-height:1.58}.formula{border:1px solid rgba(var(--module-rgb), .44);background:rgba(var(--module-rgb), .08);color:var(--module-color);border-radius:7px;grid-column:1/-1;justify-self:start;margin-top:2px;padding:7px 9px;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:13px}.lesson-shell{min-height:calc(100vh - 100px);padding:18px 0 0}.lesson-head{z-index:2;border:1px solid rgba(var(--accent-rgb), .24);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);background:#0a141dc2;border-radius:8px;grid-template-columns:auto minmax(0,1fr) auto;align-items:center;gap:18px;margin-bottom:14px;padding:14px;display:grid;position:relative;box-shadow:0 18px 48px #00000038}.back-button,.open-raw{border:1px solid rgba(var(--accent-rgb), .28);background:rgba(var(--accent-rgb), .09);min-height:42px;color:var(--accent-2);cursor:pointer;border-radius:8px;justify-content:center;gap:8px;padding:0 13px;font-size:14px;font-weight:850}.lesson-title{min-width:0}.lesson-title span{color:var(--accent);font-size:12px;font-weight:950}.lesson-title h1{color:#f5fbfd;letter-spacing:0;margin:3px 0 0;font-size:clamp(24px,2.7vw,42px);line-height:1.06}.lesson-title p{max-width:860px;color:var(--muted);margin:8px 0 0;font-size:14px;line-height:1.55}.lesson-frame-wrap{z-index:1;height:calc(100vh - 190px);min-height:640px;box-shadow:none;background:0 0;border:0;border-radius:0;position:relative;overflow:hidden}.lesson-frame-wrap iframe{background:#fff;border:0;width:100%;height:100%}.lesson-glow{z-index:0;pointer-events:none;width:60vw;height:60vw;position:fixed;bottom:-30vh;right:-18vw}.site-footer{border-top:1px solid var(--line);justify-content:center;margin-top:30px;padding:24px 0 2px;display:flex}.beian-link{color:var(--muted);border-radius:6px;align-items:center;gap:8px;font-size:14px;line-height:1.5;transition:color .18s;display:inline-flex}.beian-link img{object-fit:contain;flex:none;width:18px;height:20px;display:block}.beian-link:hover{color:var(--ink)}.beian-link:focus-visible{outline:2px solid var(--accent);outline-offset:5px}@media (width<=1180px){.topbar{grid-template-columns:1fr}.hero{grid-template-columns:1fr;min-height:auto}.module-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media (width<=760px){.app-shell{padding:14px 14px 28px}.subject-nav{grid-template-columns:1fr;display:grid}.subject-nav button{min-height:48px}.hero-copy h1{font-size:42px}.math-stage{min-height:430px}.section-head,.lesson-head{flex-direction:column;align-items:stretch;display:flex}.module-grid{grid-template-columns:1fr}.module-link{min-height:210px}.lesson-frame-wrap{height:72vh;min-height:520px}.back-button,.open-raw{width:100%}}@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,:before,:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}