.guided-lesson { --lesson-accent: #b9e9cd; --card-footer-color: #95b9ab; display: flex; flex-direction: column; gap: var(--card-footer-gap); width: 100%; height: 100%; min-height: 0; padding: var(--format-top) max(var(--edge), env(safe-area-inset-right)) var(--content-bottom) max(var(--edge), env(safe-area-inset-left)); color: #f3f8ee; background: radial-gradient(ellipse at 85% 10%, #3b6f5b44, transparent 65%), #173b3a; }
.guided-lesson button, .guided-lesson input { font: inherit; -webkit-tap-highlight-color: transparent; }
.guided-lesson button { cursor: pointer; }
.guided-lesson button:focus-visible, .guided-lesson input:focus-visible, .guided-lesson__scroll:focus-visible { outline: 2px solid #edcf91; outline-offset: 3px; }
.guided-lesson button:disabled { cursor: default; opacity: .45; }
.guided-lesson__scroll { flex: 1; min-height: 0; overflow-y: auto; scrollbar-width: thin; scrollbar-color: #5b8574 transparent; }
.guided-lesson__scroll.is-scrollable { touch-action: pan-y; }
.guided-lesson__body { display: flex; flex-direction: column; gap: 14px; width: 100%; max-width: 600px; min-height: 100%; margin-inline: auto; padding: 8px 0 2px; }
.guided-lesson__intro { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.guided-lesson__intro > div { min-width: 0; }
.guided-lesson__step-nav { display: flex; align-items: center; gap: 10px; min-height: 12px; margin-bottom: 8px; }
.guided-lesson__eyebrow { margin: 0; color: #a4c8b6; font-size: 9px; font-weight: 650; line-height: 12px; letter-spacing: .12em; }
.guided-lesson__title { margin: 0; font-size: clamp(25px, 3.4vw, 34px); font-weight: 650; line-height: 1.15; letter-spacing: -.04em; overflow-wrap: anywhere; }
.guided-lesson__title:focus { outline: none; }
.guided-lesson__voice { flex: none; display: grid; place-items: center; width: 44px; height: 44px; padding: 10px; border: 1px solid #709a8466; border-radius: 50%; background: transparent; color: #cce4d5; }
.guided-lesson__voice svg { width: 22px; height: 22px; }
.guided-lesson__voice[aria-pressed="false"] { color: #90afa0; }
.guided-lesson__progress { display: grid; grid-auto-flow: column; grid-auto-columns: 1fr; gap: 5px; }
.guided-lesson__dot { height: 3px; border-radius: 3px; background: #527265; }
.guided-lesson__dot.is-past { background: #89b99e; }
.guided-lesson__dot[aria-current] { background: #d3ecc0; }
.guided-lesson__stage { display: flex; flex: 1; flex-direction: column; justify-content: center; gap: 20px; padding-block: 12px; }
.guided-lesson__text { margin: 0; color: #ebf3e8; font-size: clamp(17px, 2vw, 20px); line-height: 1.5; letter-spacing: -.015em; text-wrap: pretty; }
.guided-lesson__figure { margin: 0; padding: 13px 12px 4px; border-radius: 20px; background: #f5f8f0; color: #295b4d; }
.guided-lesson__equation { margin: 0; text-align: center; font: 500 clamp(22px, 4vw, 27px)/1.3 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; letter-spacing: -.04em; }
.guided-lesson .graph-lab__plot { display: block; width: 100%; height: 230px; max-height: 29dvh; min-height: 0; }
.guided-lesson .graph-lab__line { stroke: #177f62; stroke-width: 3; }
.guided-lesson .graph-lab__triangle { stroke: #177f62; stroke-width: 2; }
.guided-lesson .graph-lab__reference { stroke: #81988b; }
.guided-lesson[data-focus="origin"] .graph-lab__intercept-point, .guided-lesson[data-focus="intercept"] .graph-lab__intercept-point { r: 7px; stroke: #e9c580; stroke-width: 4; }
.guided-lesson__assessment { display: grid; gap: 8px; margin: 0; padding: 0; border: 0; min-width: 0; }
.guided-lesson__choice { display: flex; align-items: center; gap: 10px; min-height: 46px; padding: 10px 12px; border: 1px solid #658c79; border-radius: 12px; color: #d3e9d8; font-size: 13px; line-height: 1.35; cursor: pointer; }
.guided-lesson__choice input { flex: none; width: 16px; height: 16px; margin: 0; accent-color: #b9e9cd; }
.guided-lesson__choice.is-selected { background: #b9e9cd20; border-color: #b9e9cd; }
.guided-lesson__choice.is-answer { background: #b9e9cd; border-color: #b9e9cd; color: #173b3a; }
.guided-lesson__choice.is-answer input { accent-color: #285f48; }
.guided-lesson.is-checked .guided-lesson__choice:not(.is-selected):not(.is-answer) { display: none; }
.guided-lesson__dock { display: grid; gap: 12px; padding-top: 14px; border-top: 1px solid #b9e9cd29; }
.guided-lesson__feedback strong { display: block; color: #9ec6b2; font-size: 10px; font-weight: 650; letter-spacing: .04em; }
.guided-lesson__feedback-heading { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.guided-lesson__feedback p { margin: 5px 0 0; color: #c3dac8; font-size: 13px; line-height: 1.5; }
.guided-lesson__feedback[data-result="understood"] strong { color: #d7edb8; font-size: 16px; }
.guided-lesson__feedback[data-result="retry"] strong { color: #edcf91; font-size: 16px; }
.guided-lesson__controls { display: flex; align-items: center; gap: 12px; }
.guided-lesson__tutor { flex: none; width: 56px; height: 56px; }
.guided-lesson__tutor svg { display: block; width: 100%; height: 100%; }
.guided-lesson__mouth, .guided-lesson__halo { transform-box: fill-box; transform-origin: center; }
.guided-lesson__halo { opacity: .2; }
.guided-lesson.is-speaking .guided-lesson__halo { animation: lesson-tutor-speaking 1.6s ease-in-out infinite; }
.guided-lesson.is-speaking .guided-lesson__mouth { animation: lesson-tutor-mouth .32s ease-in-out infinite alternate; }
.guided-lesson__actions { display: grid; flex: 1; min-width: 0; grid-template-columns: minmax(0, 1fr); }
.guided-lesson__back { display: inline-flex; flex: none; align-items: center; justify-content: center; gap: 3px; min-width: 24px; min-height: 24px; margin-block: -6px; padding: 0; border: 0; border-radius: 4px; background: transparent; color: #c3dac8; font-size: 10px !important; line-height: 1 !important; }
.guided-lesson__back svg { width: 15px; height: 15px; }
.guided-lesson__back:hover { color: #f3f8ee; }
.guided-lesson__next { min-height: 48px; padding: 10px 12px; border: 1px solid #cbe8b5; border-radius: 14px; background: #cbe8b5; color: #1d4335; font-size: 14px !important; font-weight: 650 !important; }
.guided-lesson__reveal { justify-self: end; min-height: 44px; padding: 6px 3px; border: 0; background: transparent; color: #e8d5aa; font-size: 12px !important; text-decoration: underline; text-underline-offset: 4px; }
.guided-lesson__error { margin: 0; color: #f6d7b1; font-size: 12px; line-height: 1.5; }
.guided-lesson.is-question .graph-lab__plot { height: 170px; max-height: 23dvh; }
.guided-lesson.is-question .guided-lesson__stage { gap: 12px; padding-block: 4px; }
@keyframes lesson-tutor-speaking { 0%, 100% { opacity: .2; transform: scale(.96); } 50% { opacity: .7; transform: scale(1.025); } }
@keyframes lesson-tutor-mouth { from { transform: scaleY(.55); } to { transform: scaleY(1.4); } }
@media (max-height: 740px) {
  .guided-lesson__body { gap: 10px; padding-top: 3px; }
  .guided-lesson__title { font-size: 24px; }
  .guided-lesson__step-nav { margin-bottom: 8px; }
  .guided-lesson__stage { gap: 12px; padding-block: 4px; }
  .guided-lesson__text { font-size: 16px; }
  .guided-lesson .graph-lab__plot { height: 170px; max-height: 26dvh; }
  .guided-lesson__assessment { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 6px; }
  .guided-lesson__choice { flex-direction: column; justify-content: center; gap: 6px; padding: 10px 6px; text-align: center; font-size: 11px; }
  .guided-lesson.is-checked .guided-lesson__assessment { display: flex; }
  .guided-lesson.is-checked .guided-lesson__choice { flex: 1; flex-direction: row; min-height: 44px; }
  .guided-lesson.is-question .graph-lab__plot { height: 125px; }
  .guided-lesson__dock { gap: 9px; padding-top: 10px; }
  .guided-lesson__feedback p { font-size: 12px; }
  .guided-lesson__tutor { width: 48px; height: 48px; }
  .guided-lesson.is-checked .graph-lab__plot { height: 90px; }
}
@media (max-height: 600px) {
  .guided-lesson__body { gap: 8px; }
  .guided-lesson__title { font-size: 22px; }
  .guided-lesson__text { font-size: 14px; }
  .guided-lesson__figure { padding: 8px 8px 0; }
  .guided-lesson .graph-lab__plot { height: 130px; }
  .guided-lesson.is-question .graph-lab__plot { height: 95px; }
  .guided-lesson.is-checked .graph-lab__plot { height: 70px; }
  .guided-lesson__equation { font-size: 21px; }
  .guided-lesson__choice { min-height: 44px; padding: 7px 5px; }
  .guided-lesson__dock { gap: 8px; padding-top: 8px; }
  .guided-lesson__feedback p { font-size: 11px; line-height: 1.4; }
  .guided-lesson__feedback strong { font-size: 9px; }
  .guided-lesson__feedback[data-result="understood"] strong, .guided-lesson__feedback[data-result="retry"] strong { font-size: 14px; }
  .guided-lesson__next { min-height: 44px; }
  .guided-lesson.is-checked .guided-lesson__body { gap: 5px; }
  .guided-lesson.is-checked .guided-lesson__stage { gap: 8px; }
}
@media (prefers-reduced-motion: reduce) { .guided-lesson.is-speaking .guided-lesson__halo, .guided-lesson.is-speaking .guided-lesson__mouth { animation: none; } }