.lesson-main {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  padding: clamp(3.5rem, 8vw, 7.5rem) 0 7rem;
}

.lesson-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(280px, 0.75fr);
  gap: clamp(2rem, 7vw, 7rem);
  align-items: end;
  padding-bottom: clamp(2.5rem, 6vw, 5rem);
  border-bottom: 1px solid var(--line);
}

.lesson-hero h1 {
  max-width: 850px;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(3.2rem, 7.4vw, 6.8rem);
  font-weight: 600;
  letter-spacing: -0.055em;
  line-height: 0.93;
}

.lesson-hero h1 em { color: var(--teal-deep); font-weight: 400; }
.lesson-deck {
  max-width: 760px;
  margin: 1.6rem 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(1.16rem, 2vw, 1.45rem);
  line-height: 1.5;
}

.lesson-promise {
  margin: 0;
  padding: 1.3rem 0 0 1.35rem;
  border-left: 2px solid var(--coral);
  color: var(--ink-soft);
}
.lesson-promise strong { display: block; margin-bottom: 0.35rem; color: var(--ink); }

.lesson-workbench {
  margin: clamp(2.5rem, 6vw, 5rem) 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 2rem;
  background: color-mix(in srgb, var(--card) 93%, var(--teal) 7%);
  box-shadow: var(--shadow);
}

.workbench-bar {
  display: flex;
  gap: 1rem;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--paper-deep) 58%, transparent);
}
.workbench-bar p { margin: 0; color: var(--ink-soft); font-size: 0.82rem; }
.workbench-status { display: inline-flex; gap: 0.5rem; align-items: center; color: var(--teal-deep); font-size: 0.75rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; }
.workbench-status::before { width: 0.55rem; height: 0.55rem; border-radius: 50%; background: var(--teal); content: ""; box-shadow: 0 0 0 5px color-mix(in srgb, var(--teal) 16%, transparent); }

.workbench-grid {
  display: grid;
  grid-template-columns: minmax(245px, 0.7fr) minmax(360px, 1.3fr);
  min-height: 530px;
}
.workbench-controls { padding: clamp(1.25rem, 3vw, 2rem); border-right: 1px solid var(--line); }
.workbench-stage { position: relative; display: grid; min-width: 0; place-items: center; padding: clamp(1.25rem, 4vw, 3rem); background: radial-gradient(circle at 50% 42%, color-mix(in srgb, var(--teal) 10%, transparent), transparent 46%); }

.control-group + .control-group { margin-top: 1.6rem; }
.control-label { display: block; margin-bottom: 0.55rem; color: var(--ink); font-size: 0.78rem; font-weight: 800; letter-spacing: 0.06em; text-transform: uppercase; }
.segmented { display: flex; flex-wrap: wrap; gap: 0.45rem; }
.segmented button,
.lesson-button {
  min-height: 2.55rem;
  padding: 0.48rem 0.78rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 750;
}
.segmented button:hover, .lesson-button:hover { border-color: var(--teal); color: var(--teal-deep); }
.segmented button[aria-pressed="true"], .lesson-button.is-active { border-color: var(--ink); background: var(--ink); color: var(--paper); }
.lesson-button:focus-visible, .segmented button:focus-visible, .pixel-input:focus-visible, .lesson-select:focus-visible, .lesson-range:focus-visible { outline: 3px solid color-mix(in srgb, var(--teal) 42%, transparent); outline-offset: 2px; }

.range-row { display: grid; grid-template-columns: 1fr 4.3rem; gap: 0.8rem; align-items: center; }
.lesson-range { width: 100%; accent-color: var(--teal-deep); }
.range-value { padding: 0.35rem 0.5rem; border: 1px solid var(--line); border-radius: 0.55rem; background: var(--card); color: var(--ink); font-variant-numeric: tabular-nums; text-align: center; }
.lesson-select { width: 100%; min-height: 2.8rem; padding: 0.48rem 0.72rem; border: 1px solid var(--line); border-radius: 0.7rem; background: var(--card); color: var(--ink); }
.control-note { margin: 0.55rem 0 0; color: var(--ink-soft); font-size: 0.78rem; line-height: 1.5; }

.pixel-editor { display: grid; grid-template-columns: repeat(3, minmax(3.2rem, 1fr)); gap: 0.35rem; }
.pixel-cell { position: relative; display: grid; aspect-ratio: 1; place-items: center; overflow: hidden; border: 1px solid var(--line); border-radius: 0.65rem; }
.pixel-cell::before { position: absolute; inset: 0; background: rgb(var(--pixel), var(--pixel), var(--pixel)); content: ""; }
.pixel-input { position: relative; z-index: 1; width: 100%; height: 100%; padding: 0; border: 0; background: transparent; color: var(--pixel-ink); font-size: 0.76rem; font-weight: 850; text-align: center; text-shadow: 0 1px 2px rgba(0,0,0,.22); }
.pixel-input::-webkit-inner-spin-button { display: none; }

.scharr-stage { width: min(100%, 660px); }
.scharr-visual { display: grid; grid-template-columns: minmax(160px, 0.8fr) minmax(180px, 1fr); gap: clamp(1rem, 4vw, 2.5rem); align-items: center; }
.kernel-pair { display: grid; gap: 1rem; }
.kernel-card { padding: 1rem; border: 1px solid var(--line); border-radius: 1rem; background: color-mix(in srgb, var(--card) 88%, transparent); }
.kernel-card h3 { margin: 0 0 0.65rem; font-family: var(--serif); font-size: 1rem; }
.kernel-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.18rem; }
.kernel-grid span { display: grid; min-height: 2.05rem; place-items: center; border-radius: 0.32rem; background: color-mix(in srgb, var(--paper-deep) 74%, transparent); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.78rem; }
.kernel-card.is-x .kernel-grid span:nth-child(3n+1) { color: var(--coral); }
.kernel-card.is-x .kernel-grid span:nth-child(3n) { color: var(--teal-deep); }
.kernel-card.is-y .kernel-grid span:nth-child(-n+3) { color: var(--coral); }
.kernel-card.is-y .kernel-grid span:nth-child(n+7) { color: var(--teal-deep); }

.gradient-dial { width: 100%; overflow: visible; }
.dial-ring { fill: color-mix(in srgb, var(--card) 82%, transparent); stroke: var(--line); stroke-width: 1.5; }
.dial-axis { stroke: var(--line); stroke-width: 1; }
.dial-arrow { stroke: var(--coral); stroke-width: 6; stroke-linecap: round; }
.dial-arrowhead { fill: var(--coral); }
.dial-edge { stroke: var(--teal-deep); stroke-width: 4; stroke-linecap: round; stroke-dasharray: 7 7; }
.dial-label { fill: var(--ink-soft); font: 700 12px var(--sans); }
.dial-origin { fill: var(--ink); }

.readout-grid { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line); }
.readout-item { min-width: 0; padding: 1.15rem 1.2rem; border-right: 1px solid var(--line); }
.readout-item:last-child { border-right: 0; }
.readout-item span { display: block; color: var(--ink-soft); font-size: 0.69rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; }
.readout-item strong { display: block; margin-top: 0.2rem; overflow-wrap: anywhere; font-family: var(--serif); font-size: clamp(1.15rem, 2.4vw, 1.7rem); font-variant-numeric: tabular-nums; line-height: 1.2; }

.equation-strip { padding: 1.1rem 1.25rem; border-top: 1px solid var(--line); color: var(--ink-soft); font-family: var(--serif); font-size: 1rem; text-align: center; }
.equation-strip strong { color: var(--ink); }

.lesson-sections { display: grid; grid-template-columns: repeat(12, 1fr); gap: 1.2rem; }
.lesson-card { grid-column: span 4; padding: clamp(1.35rem, 3vw, 2.2rem); border: 1px solid var(--line); border-radius: 1.4rem; background: color-mix(in srgb, var(--card) 85%, transparent); }
.lesson-card.is-wide { grid-column: span 8; }
.lesson-card.is-full { grid-column: 1 / -1; }
.lesson-card h2 { margin: 0 0 0.75rem; font-family: var(--serif); font-size: clamp(1.4rem, 2.4vw, 2rem); line-height: 1.15; }
.lesson-card p { margin: 0; color: var(--ink-soft); }
.lesson-card p + p, .lesson-card ul + p { margin-top: 0.85rem; }
.lesson-card ul { margin: 0.8rem 0 0; padding-left: 1.2rem; color: var(--ink-soft); }
.lesson-card li + li { margin-top: 0.45rem; }
.formula { display: block; margin: 1rem 0; padding: 0.8rem 1rem; overflow-x: auto; border-left: 3px solid var(--teal); background: color-mix(in srgb, var(--teal) 8%, transparent); color: var(--ink); font-family: var(--serif); font-size: clamp(1rem, 2vw, 1.2rem); }
.lesson-card .cue { color: var(--coral); font-size: 0.72rem; font-weight: 850; letter-spacing: 0.09em; text-transform: uppercase; }

.canvas-stage { width: 100%; max-width: 760px; }
.lesson-canvas { display: block; width: 100%; height: auto; min-height: 320px; border: 1px solid var(--line); border-radius: 1.2rem; background: color-mix(in srgb, var(--card) 88%, transparent); }
.stage-caption { display: flex; flex-wrap: wrap; gap: 0.75rem 1.2rem; justify-content: center; margin: 0.8rem 0 0; color: var(--ink-soft); font-size: 0.76rem; }
.legend-swatch { display: inline-block; width: 0.72rem; height: 0.72rem; margin-right: 0.35rem; border-radius: 50%; vertical-align: -0.04rem; }
.swatch-teal { background: var(--teal); }
.swatch-coral { background: var(--coral); }
.swatch-gold { background: var(--gold); }
.matrix-readout { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.35rem; margin-top: 0.7rem; }
.matrix-readout span { display: grid; min-height: 2.3rem; place-items: center; border-radius: 0.48rem; background: color-mix(in srgb, var(--paper-deep) 70%, transparent); font-family: var(--serif); font-size: 1.05rem; font-variant-numeric: tabular-nums; }
.control-heading { margin: 0 0 0.3rem; font-family: var(--serif); font-size: 1.3rem; line-height: 1.2; }
.control-equation { margin: 0 0 1rem; color: var(--ink-soft); font-family: var(--serif); }

.complex-stage { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; width: 100%; }
.complex-panel { min-width: 0; }
.complex-panel h3 { margin: 0 0 0.45rem; color: var(--ink-soft); font-size: 0.75rem; letter-spacing: 0.08em; text-align: center; text-transform: uppercase; }
.complex-canvas { display: block; width: 100%; aspect-ratio: 1; border: 1px solid var(--line); border-radius: 1rem; background: color-mix(in srgb, var(--card) 90%, transparent); }
.formula-display { margin: 0.9rem 0 0; color: var(--ink); font-family: var(--serif); font-size: clamp(1rem, 2vw, 1.25rem); text-align: center; }

.watch-stage { width: min(100%, 780px); }
.watch-diagram { width: 100%; overflow: visible; }
.watch-flow { fill: none; stroke: var(--line); stroke-width: 5; stroke-linecap: round; }
.watch-flow.is-live { stroke: var(--gold); }
.watch-node { cursor: pointer; }
.watch-node circle, .watch-node path, .watch-node rect { transition: fill 180ms ease, stroke 180ms ease, opacity 180ms ease; }
.watch-node.is-active circle, .watch-node.is-active path, .watch-node.is-active rect { stroke: var(--coral); stroke-width: 4; }
.watch-node text { fill: var(--ink); font: 750 13px var(--sans); pointer-events: none; text-anchor: middle; }
.watch-node .watch-sub { fill: var(--ink-soft); font-size: 10px; font-weight: 600; }
.watch-energy-track { fill: color-mix(in srgb, var(--paper-deep) 80%, transparent); stroke: var(--line); }
.watch-energy-fill { fill: var(--teal); transition: width 180ms ease; }
.watch-detail { min-height: 5.5rem; margin-top: 1rem; padding: 1rem 1.1rem; border: 1px solid var(--line); border-radius: 1rem; background: color-mix(in srgb, var(--card) 86%, transparent); }
.watch-detail strong { display: block; margin-bottom: 0.25rem; font-family: var(--serif); font-size: 1.15rem; }
.watch-detail p { margin: 0; color: var(--ink-soft); font-size: 0.84rem; }
.watch-stage.is-playing .watch-rotor { animation: watch-spin 3.6s linear infinite; transform-box: fill-box; transform-origin: center; }
.watch-stage.is-playing .watch-gear-fast { animation: watch-spin 1.2s linear infinite reverse; transform-box: fill-box; transform-origin: center; }
.watch-stage.is-playing .watch-gear-slow { animation: watch-spin 2.4s linear infinite; transform-box: fill-box; transform-origin: center; }
.watch-stage.is-playing .watch-balance { animation: watch-swing 0.5s ease-in-out infinite alternate; transform-box: fill-box; transform-origin: center; }
@keyframes watch-spin { to { transform: rotate(360deg); } }
@keyframes watch-swing { from { transform: rotate(-22deg); } to { transform: rotate(22deg); } }

.atlas-layout { display: grid; grid-template-columns: minmax(250px, 0.65fr) minmax(0, 1.35fr); min-height: 650px; }
.atlas-controls { padding: clamp(1.25rem, 3vw, 2rem); border-right: 1px solid var(--line); }
.atlas-results { max-height: 720px; overflow: auto; padding: clamp(1rem, 2vw, 1.5rem); }
.atlas-search { width: 100%; min-height: 3rem; padding: 0.65rem 0.85rem; border: 1px solid var(--line); border-radius: 0.8rem; background: var(--card); color: var(--ink); }
.atlas-protocol { margin: 1.5rem 0 0; padding: 1rem; border-left: 3px solid var(--coral); background: color-mix(in srgb, var(--coral) 6%, transparent); }
.atlas-protocol strong { display: block; margin-bottom: 0.45rem; font-family: var(--serif); }
.atlas-protocol ol { margin: 0; padding-left: 1.2rem; color: var(--ink-soft); font-size: 0.82rem; }
.atlas-result-count { margin: 0 0 0.9rem; color: var(--ink-soft); font-size: 0.78rem; }
.atlas-list { display: grid; gap: 0.65rem; }
.atlas-item { padding: 1rem 1.05rem; border: 1px solid var(--line); border-radius: 1rem; background: color-mix(in srgb, var(--card) 88%, transparent); }
.atlas-item-header { display: flex; gap: 0.8rem; align-items: start; }
.atlas-number { display: grid; flex: 0 0 2.2rem; height: 2.2rem; place-items: center; border-radius: 50%; background: var(--ink); color: var(--paper); font-family: var(--serif); font-weight: 800; }
.atlas-item h3 { margin: 0; font-family: var(--serif); font-size: 1.08rem; line-height: 1.25; }
.atlas-domain { display: block; margin-top: 0.15rem; color: var(--teal-deep); font-size: 0.68rem; font-weight: 850; letter-spacing: 0.08em; text-transform: uppercase; }
.atlas-item p { margin: 0.65rem 0 0 3rem; color: var(--ink-soft); font-size: 0.85rem; }
.atlas-empty { padding: 3rem 1rem; color: var(--ink-soft); text-align: center; }

.lesson-footer-nav { display: flex; flex-wrap: wrap; gap: 0.8rem; justify-content: space-between; margin-top: 3rem; padding-top: 2rem; border-top: 1px solid var(--line); }
.lesson-footer-nav a { color: var(--teal-deep); font-weight: 750; }

@media (max-width: 860px) {
  .lesson-hero { grid-template-columns: 1fr; }
  .workbench-grid { grid-template-columns: 1fr; }
  .workbench-controls { border-right: 0; border-bottom: 1px solid var(--line); }
  .workbench-stage { min-height: 430px; }
  .lesson-card, .lesson-card.is-wide { grid-column: span 6; }
  .atlas-layout { grid-template-columns: 1fr; }
  .atlas-controls { border-right: 0; border-bottom: 1px solid var(--line); }
}

@media (max-width: 640px) {
  .lesson-main { width: min(100% - 24px, 1180px); padding-top: 2.4rem; }
  .site-header { position: relative; width: min(100% - 24px, 1180px); flex-wrap: wrap; gap: 0.8rem; }
  .site-nav { width: 100%; gap: 0.65rem; justify-content: space-between; }
  .site-nav > a { font-size: 0.7rem; }
  .theme-label { display: none; }
  .lesson-hero h1 { font-size: clamp(2.8rem, 14vw, 4.3rem); }
  .lesson-workbench { border-radius: 1.2rem; }
  .workbench-bar { align-items: flex-start; flex-direction: column; }
  .scharr-visual { grid-template-columns: 1fr; }
  .kernel-pair { grid-template-columns: 1fr 1fr; }
  .gradient-dial { max-width: 300px; margin: 0 auto; }
  .readout-grid { grid-template-columns: 1fr 1fr; }
  .readout-item:nth-child(2) { border-right: 0; }
  .readout-item:nth-child(-n+2) { border-bottom: 1px solid var(--line); }
  .lesson-card, .lesson-card.is-wide { grid-column: 1 / -1; }
  .complex-stage { grid-template-columns: 1fr; }
  .atlas-results { max-height: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}