/* A lesson is a screen: only its reading area scrolls, never its action. */
#study[data-lesson="true"] {
  height: 100vh;
  height: 100dvh;
  min-height: 0;
}
#study[data-lesson="true"] #study-root {
  height: 100%;
  min-height: 0;
  margin: 0;
  padding: 0;
}
#study .acquisition-reader {
  --lesson-success: var(--subject-biology);
  box-sizing: border-box;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  height: 100%;
  max-width: 820px;
  min-height: 0;
  padding: max(12px, env(safe-area-inset-top)) 24px 0;
}
#study .acquisition-reader .lesson-header {
  min-width: 0;
}
#study .acquisition-reader .lesson-top {
  flex-wrap: nowrap;
  gap: 10px;
}
#study .acquisition-reader .lesson-top .app-icon-button {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
}
#study .acquisition-reader .lesson-top .text-link {
  text-align: left;
  line-height: 1.2;
}
#study .acquisition-reader progress {
  margin: 10px 0 14px;
  height: 5px;
}
#study .acquisition-reader .lesson-scroll {
  min-height: 0;
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  padding: 2px 6px 16px 2px;
  scroll-padding-block: 12px;
}
#study .acquisition-reader .lesson-scroll:focus-visible {
  outline: 2px solid var(--app-accent);
  outline-offset: -2px;
  border-radius: 8px;
}
#study .acquisition-reader .lesson-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px 14px;
}
#study .acquisition-reader .lesson-meta p {
  margin: 0;
  font-size: 0.75rem;
  line-height: 1.5;
}
#study .acquisition-reader .lesson-meta .muted {
  color: var(--subject);
  font-weight: 600;
  font-size: 0.8125rem;
}
#study .acquisition-reader h1 {
  margin: 6px 0 14px;
  font-size: clamp(1.2rem, 2.1vw, 1.6rem);
  line-height: 1.25;
}
#study .acquisition-reader .lesson-stage {
  min-height: 0;
  margin: 0;
}
#study .acquisition-reader .lesson-stage > .eyebrow {
  display: block;
  margin-bottom: 8px;
  font-size: 0.75rem;
}
#study .acquisition-reader .lesson-prose {
  font-size: 1.0625rem;
  line-height: 1.55;
}
#study .acquisition-reader .lesson-prose p {
  margin: 0 0 12px;
}
#study .acquisition-reader .options {
  margin: 16px 0 8px;
  gap: 8px;
}
#study .acquisition-reader .option {
  padding: 12px 16px;
  min-height: 52px;
  border-radius: 16px;
  align-items: center;
}
#study .acquisition-reader .option .lesson-prose {
  font-size: 1rem;
  line-height: 1.4;
}
#study .acquisition-reader .option-text {
  flex: 1;
  min-width: 0;
}
#study .acquisition-reader .option-result {
  font-size: 0.75rem;
  font-weight: 650;
  color: var(--lesson-success);
  white-space: nowrap;
}
#study .acquisition-reader .option.is-correct,
#study .acquisition-reader input.is-correct {
  border-color: var(--lesson-success);
  background: color-mix(in srgb, var(--lesson-success) 12%, var(--app-surface));
}
#study .acquisition-reader .option.is-correct .option-key {
  color: var(--lesson-success);
}
#study .acquisition-reader .lesson-feedback:not(:empty) {
  margin-top: 12px;
  padding: 14px 16px;
  border: 1px solid var(--app-separator);
  border-radius: 16px;
}
#study .acquisition-reader .lesson-feedback[data-result="correct"] {
  border-color: color-mix(in srgb, var(--lesson-success) 45%, transparent);
  background: color-mix(in srgb, var(--lesson-success) 12%, var(--app-surface));
  animation: lesson-feedback-arrive 180ms ease-out both;
}
#study .acquisition-reader .lesson-feedback[data-result="correct"] strong {
  color: var(--lesson-success);
}
#study .acquisition-reader .lesson-feedback strong {
  display: flex;
  gap: 8px;
  align-items: center;
}
#study .acquisition-reader .lesson-feedback .lesson-prose {
  margin-top: 6px;
  font-size: 0.9375rem;
  line-height: 1.5;
}
#study .acquisition-reader .lesson-success-check {
  display: inline-grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--lesson-success);
  color: var(--app-bg);
  font-size: 15px;
}
#study .acquisition-reader .lesson-earlier {
  margin: 0 0 14px;
}
#study .acquisition-reader .lesson-earlier summary {
  display: list-item;
  min-height: 32px;
  font-size: 0.8125rem;
}
#study .acquisition-reader .lesson-help-anchor {
  margin-top: 12px;
}
#study .acquisition-reader .lesson-block-hint {
  font-size: 0.8125rem;
  margin: 8px 0 0;
  line-height: 1.45;
}
#study .acquisition-reader .lesson-block-hint:empty {
  display: none;
}
#study .acquisition-reader .lesson-controls {
  position: static;
  display: grid;
  gap: 6px;
  padding: 12px 0 max(8px, env(safe-area-inset-bottom));
  border-top: 1px solid var(--app-separator);
  background: var(--app-bg);
}
#study .acquisition-reader .lesson-controls > .primary {
  min-height: 52px;
  padding: 12px 20px;
  font-size: 1rem;
  border-radius: 16px;
}
#study .acquisition-reader .save-note {
  margin: 0;
  min-height: 20px;
  line-height: 20px;
  font-size: 0.75rem;
  text-align: center;
}
#study .acquisition-reader .worked-step {
  margin: 12px 0;
}
@media (max-width: 600px) {
  #study .acquisition-reader {
    padding-inline: 16px;
  }
  #study .acquisition-reader .lesson-prose {
    font-size: 1rem;
  }
  #study .acquisition-reader .option {
    gap: 10px;
    padding: 12px;
  }
}
@media (max-height: 600px) {
  #study .acquisition-reader {
    padding-top: 6px;
  }
  #study .acquisition-reader progress {
    margin: 4px 0 8px;
  }
  #study .acquisition-reader .lesson-controls {
    padding-top: 6px;
  }
}
@keyframes lesson-feedback-arrive {
  from {
    opacity: 0.5;
    transform: translateY(3px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  #study .acquisition-reader .lesson-feedback[data-result="correct"] {
    animation: none;
  }
}

/* Explicit lesson reports are available independently of analytics preferences. */
#study .lesson-report-flag { min-width:44px; min-height:44px; padding:10px; }
#study .lesson-report-form { display:grid; gap:10px; }
#study .lesson-report-form p { margin:0 0 8px; }
#study .lesson-report-form label { font-weight:600; }
#study .lesson-report-form select,
#study .lesson-report-form textarea { box-sizing:border-box; width:100%; min-width:0; min-height:44px; padding:10px; font:inherit; border:1px solid var(--app-separator); border-radius:12px; }
#study .lesson-report-form textarea { resize:vertical; }
#study .lesson-report-form .button { min-height:44px; }
#study .lesson-report-note { overflow-wrap:anywhere; }