.hero-copy h1{font-size:clamp(2.3rem,4.7vw,4.7rem);line-height:1.08;max-width:16ch}.hero-actions{order:2}.hero-copy{display:flex;flex-direction:column;align-items:flex-start}.hero-copy .eyebrow,.hero-copy h1,.hero-copy .lead,.hero-copy .intro{order:0}.hero-copy #quick-start{order:1;background:#163f36;color:#fff;border:2px solid #163f36;border-radius:12px;padding:16px 22px;margin:8px 0;font-size:1.1rem;font-weight:750}.hero-actions .primary{background:transparent;color:#163f36;border:2px solid #163f36}.hero-copy .trust,.hero-copy #resume{order:3}.course-entry{background:#e8eddc;border:1px solid #829373;border-radius:22px;padding:28px;margin:32px auto;display:flex;gap:24px;align-items:center;justify-content:space-between}.course-entry h2{margin:6px 0}.course-entry p{max-width:65ch}.course-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;list-style:none;padding:0}.course-card{border:1px solid #829373;border-radius:18px;padding:24px;background:#fff}.course-card h2{font-size:1.45rem;margin:8px 0}.course-card p{line-height:1.8}.course-day{font-weight:700;color:#38543d}.course-card [data-course-done]{display:inline-block;background:#dcebd5;border-radius:20px;padding:3px 10px;margin-inline:10px}.course-card [hidden]{display:none}.course-actions{display:flex;gap:15px;flex-wrap:wrap;align-items:center;margin-top:16px}.course-progress{padding:20px;border:1px solid #829373;border-radius:14px;background:#eef3e7}.course-progress p{margin:5px 0}.course-result{margin-block:22px}.lesson-extra{border-block-start:1px solid #829373;margin-block:28px;padding-block:20px}.lesson-extra details{border:1px solid #829373;border-radius:12px;padding:15px;margin:10px 0}.lesson-extra summary{cursor:pointer;font-weight:700}.solution-steps{margin:18px 0;border:1px solid #6e836c;border-radius:14px;padding:16px;background:#f7f9f2;color:#19382d}.solution-steps summary{font-weight:750;cursor:pointer}.solution-steps ol{padding-inline-start:24px}.solution-steps li{padding:10px 4px;border-bottom:1px solid #a4b39a}.solution-steps h3{font-size:1rem}.solution-steps button,.fold-controls button{padding:10px 16px;border:1px solid #42613f;background:#fff;color:#163f36;border-radius:8px;margin:6px;cursor:pointer;font:inherit}.solution-steps button:disabled{opacity:.65;cursor:default}.solution-formula{font-family:Arial,sans-serif;font-size:1.5rem;overflow-wrap:anywhere;text-align:center}.solution-grid{border-collapse:collapse;margin:15px auto;font-family:Arial,sans-serif}.solution-grid caption{font-size:.85rem;padding:5px}.solution-grid td{border:2px solid #47633c;padding:9px;min-width:38px;text-align:center;font-weight:700}.filled-cell{background:#d5e5c8}.empty-cell{background:#fff}.fold-scene{height:310px;display:grid;place-items:center;perspective:800px;overflow:hidden;--fold:0deg;direction:ltr}.fold-base{position:relative;transform:rotateX(25deg) rotateY(-20deg);transform-style:preserve-3d}.fold-base,.fold-face{width:60px;height:60px;border:2px solid #163f36;background:rgba(190,217,165,.94);display:grid;place-items:center;font:700 24px Arial;color:#163f36;box-sizing:border-box}.fold-face{position:absolute;transform-style:preserve-3d;transition:transform .6s}.face-a{bottom:100%;left:0;transform-origin:bottom;transform:rotateX(calc(-1 * var(--fold)))}.face-b{right:100%;top:0;transform-origin:right;transform:rotateY(var(--fold))}.face-d,.face-e{left:100%;top:0;transform-origin:left;transform:rotateY(calc(-1 * var(--fold)))}.face-f{top:100%;left:0;transform-origin:top;transform:rotateX(var(--fold))}.fold-controls{display:flex;justify-content:center;flex-wrap:wrap}.fold-controls [aria-pressed=true]{background:#163f36;color:white}.language-links{display:flex;gap:12px;flex-wrap:wrap;margin:16px 0}.language-links a{padding:7px;text-decoration:underline}.a11y-contrast .course-card,.a11y-contrast .course-entry,.a11y-contrast .course-progress,.a11y-contrast .solution-steps{background:#000;color:#fff;border-color:#fff}.a11y-contrast .course-day{color:#fff}.a11y-contrast .filled-cell{color:#163f36}.a11y-contrast .empty-cell{color:#000}@media(max-width:700px){.course-grid{grid-template-columns:1fr}.course-entry{display:block;padding:20px}.hero-copy h1{max-width:none}.course-card{padding:18px}.hero-copy #quick-start{width:100%}.fold-scene{height:270px}}@media(prefers-reduced-motion:reduce){.fold-face{transition:none}}.a11y-motion .fold-face{transition:none}

.language-links{margin-inline:auto}.fold-base,.fold-face{background:#bed9a5}.fold-base>span,.fold-face>span{backface-visibility:hidden}.fold-base:after,.fold-face:after{content:attr(data-letter);position:absolute;inset:0;display:grid;place-items:center;transform:rotateY(180deg) translateZ(.1px);backface-visibility:hidden;color:#163f36}
.a11y-contrast .course-card [data-course-done]{background:#000;color:#fff;border:1px solid #fff}.footer .brand{white-space:normal;flex-wrap:wrap;max-width:100%;overflow-wrap:anywhere}
.hero-art .orbit{inset:12px;transform:none}.hero-art .orbit-two{inset:40px 30px}

/* Search landing content and accessible document hierarchy. */
.seo-intro{padding-block:3rem;border-top:1px solid var(--line,#d6ddd7)}.seo-intro p{max-width:76ch;line-height:1.8}.seo-intro .lesson-actions{flex-wrap:wrap;gap:1rem 1.5rem}.lesson-breadcrumb{display:flex;flex-wrap:wrap;gap:.4rem;line-height:1.6;margin-bottom:1.5rem}.lesson-breadcrumb [aria-current]{overflow-wrap:anywhere}