/* REA-520: the lesson visual shares the page shell and canonical wordmark. */
.section--lesson-visual { padding-top: 1rem; padding-bottom: 1.5rem; }
.lesson-visual { --lesson-screen-height: clamp(420px, 38vw, 520px); position: relative; isolation: isolate; overflow: clip; border: 1px solid var(--line); border-radius: var(--radius-xl); background: radial-gradient(ellipse at 75% 58%, color-mix(in srgb, var(--teal) 5%, transparent), transparent 54%), var(--bg); }
.lesson-visual-scene { position: absolute; z-index: -1; inset: 0 0 auto; height: 340px; overflow: hidden; }
.lesson-visual-scene img { display: block; width: 100%; height: 100%; object-fit: cover; object-position: center 34%; }
.lesson-visual-scene::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 32%, var(--bg) 100%), linear-gradient(90deg, transparent 24%, var(--bg) 44%, var(--bg) 56%, transparent 76%); }
.lesson-visual-intro { min-height: 250px; display: flex; flex-direction: column; align-items: center; justify-content: flex-start; padding: 28px 20px 24px; text-align: center; }
.lesson-visual-intro .brand-name { font-size: 1.24rem; line-height: 1.65; }
.lesson-visual-title { margin: 20px 0 0; font-size: clamp(1.7rem, 3.2vw, 2.6rem); line-height: 1.14; letter-spacing: -.04em; font-weight: 600; }
.lesson-visual-title span { display: block; }
.lesson-visual-title span:last-child { color: var(--teal); }
.lesson-visual-stages { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); align-items: stretch; gap: clamp(16px, 2vw, 24px); padding: 0 clamp(16px, 2.8vw, 36px); }
.lesson-visual-stage { min-width: 0; padding: clamp(18px, 2vw, 24px); border: 1px solid color-mix(in srgb, var(--line-strong) 78%, transparent); border-radius: 22px; background: linear-gradient(155deg, color-mix(in srgb, var(--surface-raised) 58%, var(--surface)), var(--surface) 64%); box-shadow: 0 15px 38px #0002, inset 0 1px 0 color-mix(in srgb, var(--text) 7%, transparent); }
.lesson-visual-stage--after { border-color: color-mix(in srgb, var(--teal) 55%, var(--line)); background: radial-gradient(ellipse at 60% 30%, color-mix(in srgb, var(--teal) 11%, transparent), transparent 72%), linear-gradient(155deg, color-mix(in srgb, var(--teal) 7%, var(--surface-raised)), var(--surface) 68%); box-shadow: 0 18px 42px #0002, 0 0 34px color-mix(in srgb, var(--teal) 9%, transparent), inset 0 1px 0 color-mix(in srgb, var(--teal) 18%, transparent); }
.lesson-visual-label { display: flex; align-items: center; gap: 12px; }
.lesson-visual-label h3 { margin: 0; font-size: clamp(1.2rem, 2vw, 1.5rem); letter-spacing: -.025em; line-height: 1.3; }
.lesson-visual-number { display: grid; place-items: center; flex: 0 0 30px; height: 30px; border: 1px solid var(--line-strong); border-radius: 50%; color: var(--teal); font-size: .8rem; }
.lesson-visual-purpose { margin: 10px 0 14px; min-height: 3em; color: var(--muted-strong); font-size: .95rem; line-height: 1.5; }
.lesson-visual-screen-heading { min-height: 26px; margin-bottom: 10px; display: flex; justify-content: space-between; gap: 10px; align-items: center; color: var(--text); font-size: .95rem; font-weight: 650; }
.lesson-visual-counter { flex-shrink: 0; padding: 4px 9px; border: 1px solid color-mix(in srgb, var(--teal) 24%, transparent); border-radius: 999px; background: color-mix(in srgb, var(--teal) 8%, transparent); color: var(--text-soft); font-size: .7rem; letter-spacing: .12em; font-variant-numeric: tabular-nums; }
.lesson-visual-image { display: flex; height: var(--lesson-screen-height); align-items: center; justify-content: center; overflow: hidden; border: 1px solid color-mix(in srgb, var(--line-strong) 68%, transparent); border-radius: 15px; background: radial-gradient(ellipse at 50% 42%, color-mix(in srgb, var(--teal) 8%, var(--surface-raised)), var(--surface) 72%); }
.lesson-visual-image img { display: block; width: auto; height: auto; max-width: 100%; max-height: 100%; border-radius: 10px; border: 1px solid var(--line-strong); box-shadow: 0 16px 36px #0004; }
.lesson-visual-carousel { position: relative; padding-right: 16px; }
.lesson-visual-panel[hidden] { display: none; }
.lesson-visual-panel { animation: lesson-visual-appear .2s ease-out; }
.lesson-visual-facts { margin: 16px 0 0; min-height: 3em; color: var(--text-soft); font-size: .875rem; line-height: 1.5; }
.lesson-visual-dots { position: absolute; right: -14px; top: 36px; height: var(--lesson-screen-height); display: flex; flex-direction: column; justify-content: center; }
.lesson-visual-dot { position: relative; display: grid; place-items: center; width: 44px; height: 48px; border: 0; padding: 0; border-radius: 50%; background: transparent; color: var(--text); cursor: pointer; }
.lesson-visual-dot::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--muted); opacity: .65; transition: background .2s, box-shadow .2s; }
.lesson-visual-dot[aria-selected="true"]::before { height: 22px; border-radius: 999px; background: var(--teal); opacity: 1; box-shadow: 0 0 0 6px color-mix(in srgb, var(--teal) 10%, transparent), 0 0 18px color-mix(in srgb, var(--teal) 35%, transparent); }
.lesson-visual-dot:focus-visible { outline: 2px solid var(--teal); outline-offset: 1px; }
.lesson-visual-dot-label { pointer-events: none; position: absolute; z-index: 2; right: 40px; width: max-content; max-width: 220px; padding: 6px 10px; border: 1px solid var(--line-strong); border-radius: 8px; background: var(--surface-raised); color: var(--text); font-size: .75rem; opacity: 0; transition: opacity .15s; box-shadow: 0 5px 18px #0003; }
.lesson-visual-dot:hover .lesson-visual-dot-label, .lesson-visual-dot:focus-visible .lesson-visual-dot-label { opacity: 1; }
.lesson-visual-hint { margin: 10px 0 0; color: var(--muted-strong); font-size: .75rem; line-height: 1.5; }
.lesson-visual-source { margin: 17px 20px 20px; color: var(--muted); text-align: center; font-size: .7rem; line-height: 1.6; }
@keyframes lesson-visual-appear { from { opacity: .4; transform: translateY(3px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) { .lesson-visual-panel { animation: none; } .lesson-visual-dot::before, .lesson-visual-dot-label { transition: none; } }
@media (max-width: 900px) {
  .section--lesson-visual { padding-top: .5rem; }
  .section--lesson-visual > .section-shell { padding-inline: 12px; }
  .lesson-visual { border-radius: 24px; }
  .lesson-visual-intro { min-height: 245px; padding-top: 24px; }
  .lesson-visual-scene { height: 270px; }
  .lesson-visual-scene img { object-position: center; }
  .lesson-visual-title { margin-top: 22px; font-size: 1.7rem; }
  .lesson-visual-stages { grid-template-columns: minmax(0, 1fr); gap: 16px; padding-inline: clamp(12px, 3vw, 24px); }
  .lesson-visual-stage { padding: clamp(16px, 3vw, 22px); border-radius: 18px; }
  .lesson-visual-purpose { min-height: 0; }
  .lesson-visual { --lesson-screen-height: clamp(390px, 105vw, 510px); }
  .lesson-visual-facts { min-height: 0; }
  .lesson-visual-carousel { padding-right: 34px; }
  .lesson-visual-dots { right: -12px; }
}
@media (max-width: 400px) { .lesson-visual-intro .brand-name { font-size: 1rem; } }