.solver{--solver-cycle:40s;--solver-slot:8s;border:2px solid var(--color-line);border-radius:var(--radius-lg);background:var(--color-surface);box-shadow:0 6px 0 var(--color-line-deep);margin:0;padding:1.5rem 1.5rem 2rem;position:relative}.solver-deck{min-width:0;display:grid}.solver-slide{min-width:0;animation:solver-slide var(--solver-cycle) linear infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot));flex-direction:column;grid-area:1/1;gap:1rem;display:flex}.solver-topic{color:var(--color-muted-soft);animation:solver-rise var(--solver-cycle) ease-out infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot) + .15s);font-size:.9375rem;font-weight:800}.solver-progress{background:var(--color-line);border-radius:1rem;height:1rem;overflow:hidden}.solver-progress span{border-radius:inherit;background:var(--color-leaf);width:100%;height:100%;box-shadow:inset 0 -4px 0 var(--color-leaf-deep);transform-origin:0;animation:solver-fill var(--solver-cycle) linear infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot) + .3s);display:block}.solver-prompt{animation:solver-rise var(--solver-cycle) ease-out infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot) + .45s);font-size:clamp(1.25rem,1rem + 1.5vw,1.75rem);overflow:auto hidden}.solver-steps{color:var(--color-ink-dim);flex-direction:column;gap:.5rem;padding-inline-start:1rem;font-size:1.125rem;display:flex;position:relative}.solver-steps:before,.solver-steps:after{content:"";border-radius:3px;width:3px;position:absolute;inset-block:0;inset-inline-start:0}.solver-steps:before{background:var(--color-sky-edge)}.solver-steps:after{background:var(--color-leaf);transform-origin:top;animation:solver-rail var(--solver-cycle) linear infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot) + 1.4s)}.solver-steps li{animation:solver-step var(--solver-cycle) ease-out infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot) + 1.4s + var(--step) * 1.3s)}.solver-answer{border:2px solid var(--color-leaf-deep);border-radius:var(--radius-md);background:var(--color-leaf-night);width:fit-content;color:var(--color-leaf-light);transform-origin:0;animation:solver-pop var(--solver-cycle) ease-out infinite backwards;animation-delay:calc(var(--slide) * var(--solver-slot) + 5s);flex-wrap:wrap;align-items:center;gap:.75rem;padding:.75rem 1rem;font-size:1.25rem;display:flex}.solver-answer-label{font-size:1rem;font-weight:900}.solver-mascot{inset-inline-end:1rem;width:4.5rem;animation:solver-nod var(--solver-slot) ease-in-out infinite;position:absolute;bottom:-1.25rem}.solver-mascot svg{width:100%;height:auto}@keyframes solver-slide{0%{opacity:0;transform:translateY(12px)}1.5%,17.5%{opacity:1;transform:none}20%,to{opacity:0;transform:translateY(-10px)}}@keyframes solver-rise{0%{opacity:0;transform:translateY(8px)}1.6%,50%{opacity:1;transform:none}51%,to{opacity:0;transform:translateY(8px)}}@keyframes solver-step{0%{opacity:0;transform:translateY(8px)}1.6%{opacity:1;filter:brightness(1.35);transform:none}3.2%{opacity:1;filter:brightness(1.35)}5%,50%{opacity:.62;filter:none;transform:none}51%,to{opacity:0;transform:translateY(8px)}}@keyframes solver-fill{0%{transform:scaleX(0)}16%,50%{transform:scaleX(1)}51%,to{transform:scaleX(0)}}@keyframes solver-rail{0%{transform:scaleY(0)}7.8%,50%{transform:scaleY(1)}51%,to{transform:scaleY(0)}}@keyframes solver-pop{0%{opacity:0;transform:scale(.9)}1.1%{opacity:1}1.7%{transform:scale(1.05)}2.8%,50%{opacity:1;transform:scale(1)}51%,to{opacity:0;transform:scale(.9)}}@keyframes solver-nod{0%,62%{transform:none}67%{transform:translateY(-7px)rotate(-6deg)}72%{transform:translateY(0)rotate(4deg)}78%,to{transform:none}}@media (prefers-reduced-motion:reduce){.hero{align-items:start}.solver-deck{grid-auto-flow:row;gap:2rem}.solver-slide{grid-area:auto}.solver-slide,.solver-topic,.solver-prompt,.solver-steps li,.solver-answer,.solver-mascot{opacity:1;animation-name:none;transform:none}.solver-progress span{animation-name:none;transform:scaleX(1)}.solver-steps:after{animation-name:none;transform:scaleY(1)}}.hero{align-items:center;gap:2.5rem;padding-block-start:1rem;display:grid}.hero-copy{gap:1.5rem}.facts ul{gap:1rem;display:grid}.facts li{border-inline-start:3px solid var(--color-leaf);color:var(--color-ink-soft);padding-inline-start:1rem;font-weight:700}.how-grid,.proof-grid{gap:1.5rem;display:grid}.how-item{flex-direction:column;gap:.75rem;display:flex}.section-rail{gap:1.5rem;display:grid}.rail-group{flex-direction:column;gap:.75rem;display:flex}.rail-group h3{color:var(--color-muted-soft);font-size:1rem}.chip-list{flex-wrap:wrap;gap:.625rem;display:flex}.chip{border:2px solid var(--color-line);min-height:2.75rem;box-shadow:0 3px 0 var(--color-line);color:var(--color-ink-soft);border-radius:999px;align-items:center;padding:.5rem 1rem;text-decoration:none;display:inline-flex}.chip:hover{border-color:var(--color-sky-edge);color:var(--color-ink)}.proof-quote{border-radius:var(--radius-lg);background:var(--color-surface);flex-direction:column;gap:1rem;height:100%;margin:0;padding:1.5rem;font-size:1.125rem;display:flex}.proof-note{font-size:.9375rem}@media (width>=40rem){.facts ul,.how-grid{grid-template-columns:repeat(2,1fr)}}@media (width>=64rem){.hero{grid-template-columns:1.1fr 1fr;gap:4rem}.facts ul,.how-grid,.proof-grid{grid-template-columns:repeat(4,1fr)}.proof-grid{grid-template-columns:repeat(3,1fr)}}.unit-layout{gap:2.5rem;display:grid}.lesson-list{flex-direction:column;gap:.5rem;display:flex}.lesson-row{border:2px solid var(--color-line-deep);border-radius:var(--radius-md);align-items:center;gap:1rem;padding:.75rem 1rem;display:flex}.lesson-text{flex-direction:column;display:flex}.lesson-title{font-weight:800}.lesson-meta{font-size:.9375rem}.example-grid{gap:1.5rem;display:grid}.example-card{border:2px solid var(--color-line);border-radius:var(--radius-lg);background:var(--color-surface);flex-direction:column;gap:1rem;min-width:0;padding:1.5rem;display:flex}.example-prompt{font-size:1.25rem;overflow:auto hidden}.example-steps h3{color:var(--color-muted-soft);font-size:.9375rem}.example-steps ol{border-inline-start:3px solid var(--color-sky-edge);color:var(--color-ink-dim);flex-direction:column;gap:.375rem;padding-inline-start:1rem;display:flex;overflow:auto hidden}@media (width>=64rem){.unit-layout{grid-template-columns:2fr 1fr}.example-grid{grid-template-columns:repeat(3,1fr)}}