/* M02K10 · 1D → 2D → 3D propagation */
.spreading-chapter{padding-top:74px;padding-bottom:50px}.k10-header{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(280px,.6fr);gap:34px;align-items:end}.k10-header h2{margin:.12em 0 .22em;font-size:clamp(3.05rem,6.8vw,6.55rem);line-height:.9;letter-spacing:-.055em}.k10-header h2 em{font-weight:400;color:var(--accent)}.k10-header .lead{max-width:850px}.k10-index{padding:24px;border:1px solid var(--line);border-radius:var(--radius);background:linear-gradient(145deg,color-mix(in srgb,var(--accent-2) 10%,var(--panel)),var(--panel));box-shadow:var(--shadow)}.k10-index>span{display:block;color:var(--accent);font-size:.75rem;text-transform:uppercase;letter-spacing:.13em}.k10-index>strong{display:block;margin:10px 0;font-family:"Cambria Math","STIX Two Math",Georgia,serif;font-size:clamp(1.75rem,2.8vw,2.55rem);font-weight:500}.k10-index p{margin:0;color:var(--muted);font-size:.88rem}
.spreading-conservation,.spreading-combined,.spreading-interpretation{padding-top:58px;padding-bottom:58px}.spreading-equation-grid,.spreading-dimension-grid,.spreading-combined-grid,.spreading-interpret-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.spreading-equation-card,.spreading-dimension-card,.spreading-combined-card,.spreading-interpret-card{padding:23px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--panel)}.spreading-equation-card>span,.spreading-dimension-card>span,.spreading-combined-card>span,.spreading-interpret-card>span{display:block;color:var(--accent);font-size:.73rem;text-transform:uppercase;letter-spacing:.11em}.spreading-equation-card strong,.spreading-dimension-card strong,.spreading-combined-card strong,.spreading-interpret-card strong{display:block;margin:10px 0 7px}.spreading-equation-card p,.spreading-dimension-card p,.spreading-combined-card p,.spreading-interpret-card p{margin:12px 0 0;color:var(--muted);font-size:.86rem}.spreading-equation-card .equation,.spreading-dimension-card .equation,.spreading-combined-card .equation{margin-top:14px}.spreading-equation-card.primary,.spreading-dimension-card.key,.spreading-combined-card.primary,.spreading-interpret-card.key{border-color:color-mix(in srgb,var(--accent) 38%,var(--line));background:linear-gradient(145deg,color-mix(in srgb,var(--accent) 8%,var(--panel)),var(--panel))}.spreading-dimensions{padding:58px 0;background:color-mix(in srgb,var(--panel) 44%,transparent);border-block:1px solid var(--line)}
.spreading-lab-section{padding:62px 0;background:linear-gradient(180deg,color-mix(in srgb,var(--panel) 36%,transparent),transparent 24%,transparent 76%,color-mix(in srgb,var(--panel) 32%,transparent));border-block:1px solid var(--line)}.spreading-lab-shell{display:grid;grid-template-columns:minmax(235px,290px) minmax(0,1fr);gap:16px;align-items:start}.spreading-controls{position:sticky;top:88px;display:grid;gap:14px;padding:18px;border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);box-shadow:var(--shadow)}.spreading-dimension-buttons,.spreading-preset-row{display:grid;grid-template-columns:repeat(3,1fr);gap:7px}.spreading-preset-row{grid-template-columns:1fr 1fr}.spreading-dimension-buttons button,.spreading-preset-row button{min-height:36px;padding:7px;border:1px solid var(--line);border-radius:9px;background:var(--panel-2);color:var(--muted);font:inherit;font-size:.72rem;cursor:pointer}.spreading-dimension-buttons button:hover,.spreading-dimension-buttons button:focus-visible,.spreading-preset-row button:hover,.spreading-preset-row button:focus-visible{border-color:var(--accent);color:var(--text)}.spreading-dimension-buttons button.active{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 14%,var(--panel-2));color:var(--text)}.spreading-actions{display:grid;grid-template-columns:1fr 1fr;gap:8px}.spreading-main{display:grid;gap:12px;min-width:0}.spreading-panel{border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);overflow:hidden}.spreading-panel-head{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:16px 18px;border-bottom:1px solid var(--line)}.spreading-panel-head>div>span{display:block;color:var(--muted);font-size:.72rem;text-transform:uppercase;letter-spacing:.1em}.spreading-panel-head>div>strong{display:block;margin-top:4px}.spreading-status{display:flex;align-items:center;gap:7px;color:var(--muted);font-size:.74rem}.spreading-status i{width:8px;height:8px;border-radius:50%;background:var(--accent-3);box-shadow:0 0 12px color-mix(in srgb,var(--accent-3) 70%,transparent)}
.spreading-geometry-svg,.spreading-decay-svg{display:block;width:100%;height:auto;background:radial-gradient(circle at 32% 45%,color-mix(in srgb,var(--accent-2) 6%,transparent),transparent 52%)}.spread-front{fill:none;stroke:var(--accent);stroke-width:1.7;vector-effect:non-scaling-stroke}.spread-front.secondary{stroke:var(--accent-2);opacity:.58}.spread-meridian{fill:none;stroke:var(--accent-2);stroke-width:1.1;stroke-dasharray:5 5;opacity:.68;vector-effect:non-scaling-stroke}.spread-source{fill:var(--warm);stroke:var(--bg);stroke-width:2;vector-effect:non-scaling-stroke}.spread-reference{fill:none;stroke:var(--accent-3);stroke-width:2;stroke-dasharray:7 5;vector-effect:non-scaling-stroke}.spread-probe{stroke:var(--warm);stroke-width:1.45;stroke-dasharray:4 5;vector-effect:non-scaling-stroke}.spread-probe-dot{fill:var(--warm);stroke:var(--bg);stroke-width:2;vector-effect:non-scaling-stroke}.spread-axis{stroke:var(--line-strong);stroke-width:1;vector-effect:non-scaling-stroke}.spread-geometry-label{fill:var(--text);font:700 13px/1.2 Inter,system-ui,sans-serif}.spread-geometry-muted{fill:var(--muted);font:12px/1.2 Inter,system-ui,sans-serif}.spread-geometry-warm{fill:var(--warm);font:700 13px/1.2 Inter,system-ui,sans-serif}.spreading-telemetry{display:grid;grid-template-columns:repeat(6,1fr);border-top:1px solid var(--line)}.spreading-telemetry>div{padding:13px 11px;border-right:1px solid var(--line);min-width:0}.spreading-telemetry>div:last-child{border-right:0}.spreading-telemetry span{display:block;color:var(--muted);font-size:.68rem;line-height:1.25}.spreading-telemetry strong{display:block;margin-top:5px;font-size:.82rem;font-variant-numeric:tabular-nums;white-space:nowrap}
.spreading-detail-grid{display:grid;grid-template-columns:minmax(0,1.08fr) minmax(0,.92fr);gap:12px}.spreading-decay-axis{stroke:var(--line-strong);stroke-width:1}.spreading-decay-geo,.spreading-decay-amplitude,.spreading-decay-intensity{fill:none;stroke-linecap:round;stroke-linejoin:round}.spreading-decay-geo{stroke:var(--muted);stroke-width:1.6;stroke-dasharray:4 6}.spreading-decay-amplitude{stroke:var(--accent);stroke-width:3}.spreading-decay-intensity{stroke:var(--warm);stroke-width:2.2;stroke-dasharray:7 5}.spreading-decay-probe{stroke:var(--accent-3);stroke-width:1.2;stroke-dasharray:4 4}.spreading-decay-muted{fill:var(--muted);font:12px/1.2 Inter,system-ui,sans-serif}.spreading-legend{display:flex;gap:16px;flex-wrap:wrap;padding:10px 16px;border-top:1px solid var(--line);color:var(--muted);font-size:.72rem}.spreading-legend span{display:flex;align-items:center;gap:7px}.spreading-legend i{width:22px;height:0;border-top:2px solid}.spreading-legend i.geo{border-color:var(--muted);border-top-style:dashed}.spreading-legend i.amp{border-color:var(--accent)}.spreading-legend i.int{border-color:var(--warm);border-top-style:dashed}
.spreading-budget{display:grid;gap:17px;padding:22px 18px}.spread-budget-row>div:first-child{display:flex;justify-content:space-between;gap:12px;align-items:baseline}.spread-budget-row span{color:var(--muted);font-size:.76rem}.spread-budget-row strong{font-size:.78rem;font-weight:600;font-variant-numeric:tabular-nums}.spread-budget-track{height:8px;margin-top:7px;border-radius:99px;background:var(--panel-2);overflow:hidden;border:1px solid var(--line)}.spread-budget-track i{display:block;height:100%;width:100%;border-radius:inherit;background:linear-gradient(90deg,var(--accent),var(--accent-3));transform-origin:left}.spreading-scale-grid{display:grid;grid-template-columns:1fr 1fr;border-top:1px solid var(--line)}.spreading-scale-grid>div{padding:13px 16px;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.spreading-scale-grid>div:nth-child(2n){border-right:0}.spreading-scale-grid>div:nth-last-child(-n+2){border-bottom:0}.spreading-scale-grid span{display:block;color:var(--muted);font-size:.7rem}.spreading-scale-grid strong{display:block;margin-top:5px;font-size:.84rem;font-variant-numeric:tabular-nums}.spreading-reading-card{padding:21px 22px;border:1px solid var(--line);border-radius:var(--radius);background:linear-gradient(145deg,color-mix(in srgb,var(--accent-2) 6%,var(--panel)),var(--panel))}.spreading-reading-card h3{margin:7px 0 0}.spreading-reading-card p{margin:12px 0 0;color:var(--muted);font-size:.88rem}.spreading-next{margin-top:10px}
@media(max-width:1120px){.spreading-lab-shell{grid-template-columns:1fr}.spreading-controls{position:static;grid-template-columns:repeat(2,minmax(0,1fr))}.spreading-dimension-buttons,.spreading-preset-row,.spreading-actions{align-self:end}.spreading-telemetry{grid-template-columns:repeat(3,1fr)}.spreading-telemetry>div:nth-child(3){border-right:0}.spreading-telemetry>div:nth-child(-n+3){border-bottom:1px solid var(--line)}}
@media(max-width:980px){.k10-header{grid-template-columns:1fr}.k10-index{max-width:680px}.spreading-equation-grid,.spreading-dimension-grid,.spreading-combined-grid,.spreading-interpret-grid{grid-template-columns:1fr 1fr}.spreading-equation-card.primary,.spreading-combined-card.primary{grid-column:1/-1}.spreading-detail-grid{grid-template-columns:1fr}.spreading-interpret-card:last-child{grid-column:1/-1}}
@media(max-width:680px){.spreading-chapter{padding-top:56px;padding-bottom:42px}.k10-header h2{font-size:clamp(2.35rem,11.5vw,4.3rem)}.spreading-conservation,.spreading-dimensions,.spreading-combined,.spreading-lab-section,.spreading-interpretation{padding-top:44px;padding-bottom:44px}.spreading-equation-grid,.spreading-dimension-grid,.spreading-combined-grid,.spreading-interpret-grid{grid-template-columns:1fr}.spreading-equation-card.primary,.spreading-combined-card.primary,.spreading-interpret-card:last-child{grid-column:auto}.spreading-controls{grid-template-columns:1fr}.spreading-panel-head{align-items:flex-start}.spreading-status{padding-top:3px}.spreading-telemetry{grid-template-columns:1fr 1fr}.spreading-telemetry>div{border-right:1px solid var(--line);border-bottom:1px solid var(--line)}.spreading-telemetry>div:nth-child(2n){border-right:0}.spreading-telemetry>div:nth-last-child(-n+2){border-bottom:0}.spreading-geometry-svg{min-height:245px}.spreading-decay-svg{min-height:215px}}
@media(max-width:390px){.k10-index,.spreading-equation-card,.spreading-dimension-card,.spreading-combined-card,.spreading-reading-card{padding:18px}.spreading-controls{padding:14px}.spreading-dimension-buttons button,.spreading-preset-row button{min-height:34px}.spreading-panel-head{padding:13px 14px}.spreading-panel-head>div>strong{font-size:.84rem}.spreading-telemetry>div{padding:11px 9px}.spreading-telemetry strong{font-size:.75rem}.spreading-geometry-svg{min-height:235px}.spread-geometry-label,.spread-geometry-warm{font-size:16px}.spread-geometry-muted,.spreading-decay-muted{font-size:15px}.spreading-decay-svg{min-height:210px}.spreading-budget{padding:18px 14px}.spread-budget-row>div:first-child{display:block}.spread-budget-row strong{display:block;margin-top:3px}.spreading-scale-grid>div{padding:11px 12px}.spreading-actions .button{padding-inline:8px}}