/* Public learning invitation; shared DTC tokens remain the visual owner. */
/* The small existing copyright text must remain readable at mobile size. */
.site-footer > p { color: var(--ui-muted, var(--muted)); }
.site-header .header-entry-actions { display: flex; align-items: stretch; gap: 10px; flex-shrink: 0; }
.site-header .header-entry-actions > a { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; border-radius: var(--ui-control-radius, 12px); line-height: 1.5; text-decoration: none; transition: background-color 150ms ease, border-color 150ms ease; }
.site-header .header-register { text-align: center; }
.site-header .header-register:hover { background: var(--ui-ink, var(--navy-2)); }
.header-playground { gap: 8px; padding: 9px 15px; border: 1px solid var(--brand-blue, var(--navy)); background: var(--ui-surface, var(--white)); color: var(--brand-blue, var(--navy)); font-size: 14px; font-weight: 850; }
.header-playground-letter { font-family: var(--ui-title-font, inherit); font-size: 25px; line-height: 1; color: var(--ui-focus, var(--magenta)); }
.header-playground:hover { background: var(--ui-tint, var(--mint-soft)); }
.site-header .header-entry-actions > a:active { background: var(--ui-line, var(--line)); color: var(--ui-ink, var(--navy)); }
.site-header .header-entry-actions > a:focus-visible, .playground-open:focus-visible { outline: 3px solid var(--ui-focus, var(--magenta)); outline-offset: 4px; }

.playground-section { width: min(1160px, calc(100% - 44px)); margin: 0 auto; padding-block: 92px 28px; display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: clamp(30px, 5vw, 76px); align-items: center; }
.playground-copy, .playground-preview { min-width: 0; }
.playground-copy .eyebrow { letter-spacing: 0; }
.playground-copy h2 { margin: 0; font-family: var(--ui-title-font, inherit); font-size: clamp(36px, 4.5vw, 58px); line-height: 1.35; color: var(--ui-ink, var(--navy)); }
.playground-tagline { margin: 9px 0 0; color: var(--brand-blue, var(--navy)); font-size: clamp(20px, 2vw, 25px); font-weight: 750; line-height: 1.7; }
.playground-intro { margin: 18px 0 22px; color: var(--ui-muted, var(--muted)); font-size: 17px; line-height: 1.95; }
.playground-features { display: grid; gap: 17px; margin: 0 0 28px; padding: 0; list-style: none; }
.playground-features li { padding-inline-start: 16px; border-inline-start: 3px solid var(--brand-green, var(--lime)); }
.playground-features li:nth-child(2) { border-color: var(--brand-blue, var(--navy)); }
.playground-features li:nth-child(3) { border-color: var(--brand-magenta, var(--magenta)); }
.playground-features strong, .playground-features span { display: block; }
.playground-features strong { font-size: 16px; line-height: 1.65; color: var(--ui-ink, var(--navy)); }
.playground-features span { margin-top: 3px; font-size: 14px; line-height: 1.8; color: var(--ui-muted, var(--muted)); }
.playground-open { display: inline-flex; align-items: center; justify-content: center; gap: 24px; min-height: 54px; padding: 12px 22px; border: 1px solid transparent; border-radius: var(--ui-control-radius, 12px); color: var(--ui-surface, var(--white)); background: var(--brand-blue, var(--navy)); font-size: 16px; font-weight: 850; line-height: 1.5; text-decoration: none; transition: background-color 150ms ease; }
.playground-open > span { color: var(--brand-green, var(--lime)); font-size: 23px; }
.playground-open:hover { background: var(--ui-ink, var(--navy-2)); }
.playground-open:active { background: var(--ui-focus, var(--magenta)); }
.playground-note { max-width: 460px; margin: 14px 0 0; color: var(--ui-muted, var(--muted)); font-size: 12px; line-height: 1.9; }

.playground-preview { margin: 0; padding: clamp(20px, 3vw, 36px); border: 1px solid var(--ui-line, var(--line)); border-radius: 32px; background: var(--ui-tint, var(--mint-soft)); }
.playground-preview-art { padding-block: 8px 30px; }
.playground-preview-label { color: var(--brand-blue, var(--navy)); font-size: 15px; font-weight: 750; margin-bottom: 24px; }
.playground-letter-tiles { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; align-items: center; }
.playground-letter-tiles > span { display: grid; place-items: center; aspect-ratio: 1 / 1.15; border: 1px solid var(--ui-line, var(--line)); border-radius: 24px; background: var(--ui-surface, var(--white)); color: var(--brand-blue, var(--navy)); font-family: var(--ui-title-font, inherit); font-size: clamp(64px, 7vw, 98px); line-height: 1.45; box-shadow: 0 6px 0 var(--ui-line, var(--line)); }
.playground-letter-tiles > span:first-child { transform: rotate(5deg); }
.playground-letter-tiles > span:nth-child(2) { transform: translateY(-10px); color: var(--ui-success, var(--mint)); border-color: var(--brand-green, var(--lime)); }
.playground-letter-tiles > span:last-child { transform: rotate(-5deg); color: var(--ui-focus, var(--magenta)); }
.playground-word-trail { display: flex; align-items: center; justify-content: space-between; gap: 14px; margin-top: 38px; padding: 16px 4px; border-block-end: 2px dashed var(--ui-line, var(--line)); font-family: var(--ui-title-font, inherit); }
.playground-word-parts { color: var(--brand-blue, var(--navy)); font-size: clamp(23px, 3vw, 35px); white-space: nowrap; }
.playground-word-parts i { font: inherit; color: var(--ui-muted, var(--muted)); }
.playground-trail-arrow { color: var(--ui-success, var(--mint)); font-size: 28px; }
.playground-word-trail > strong { font-size: clamp(38px, 4vw, 58px); line-height: 1.5; color: var(--ui-ink, var(--navy)); }
.playground-preview figcaption strong, .playground-preview figcaption span { display: block; }
.playground-preview figcaption strong { font-size: 20px; line-height: 1.7; color: var(--ui-ink, var(--navy)); }
.playground-preview figcaption span { margin-top: 5px; font-size: 14px; line-height: 1.8; color: var(--ui-muted, var(--muted)); }

@media (max-width: 1100px) {
  .site-header { gap: 18px; }
  .site-header nav { gap: 16px; }
  .site-header .header-entry-actions { gap: 8px; }
  .header-playground { padding-inline: 12px; }
}
@media (max-width: 920px) {
  .playground-section { grid-template-columns: minmax(0, 1fr) minmax(0, .8fr); gap: 28px; padding-top: 64px; }
  .playground-preview { padding: 22px; border-radius: 24px; }
  .playground-letter-tiles { gap: 7px; }
  .playground-letter-tiles > span { font-size: 58px; border-radius: 18px; }
  .playground-word-trail { gap: 8px; }
  .playground-word-parts { font-size: 22px; }
  .playground-word-trail > strong { font-size: 38px; }
}
@media (max-width: 700px) {
  .site-header { height: auto; min-height: 86px; flex-wrap: wrap; padding-block: 10px; gap: 10px; }
  .site-header .brand { flex: 1 1 100%; }
  .site-header .header-entry-actions { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); width: 100%; }
  .site-header .header-entry-actions > a { min-height: 48px; padding: 9px 8px; font-size: 13px; }
  .header-playground-letter { font-size: 22px; }
  .playground-section { grid-template-columns: minmax(0, 1fr); gap: 32px; width: calc(100% - 32px); padding-block: 54px 0; }
  .playground-intro { font-size: 16px; }
  .playground-preview { width: 100%; max-width: 500px; justify-self: center; }
  .playground-letter-tiles > span { font-size: clamp(62px, 15vw, 92px); }
  .playground-preview-art { padding-bottom: 24px; }
  .playground-word-parts { font-size: clamp(25px, 6vw, 35px); }
  .playground-word-trail > strong { font-size: clamp(40px, 10vw, 54px); }
  .playground-open { width: 100%; }
}
@media (prefers-reduced-motion: reduce) {
  .site-header .header-entry-actions > a, .playground-open { transition: none; }
}
@media (forced-colors: active) {
  .site-header .header-entry-actions > a, .playground-preview, .playground-letter-tiles > span, .playground-open { border-color: CanvasText; }
  .site-header .header-entry-actions > a:focus-visible, .playground-open:focus-visible { outline-color: Highlight; }
  .playground-letter-tiles > span { box-shadow: none; }
}