:root {
  --color-bg: #f2f8fb;
  --color-surface: #ffffff;
  --color-surface-alt: rgba(255, 255, 255, 0.72);
  --color-text: #0e2740;
  --color-muted: #456072;
  --color-accent: #1e9bd7;
  --color-accent-strong: #116a9a;
  --color-highlight: #74e0dd;
  --shadow-soft: 0 16px 40px rgba(14, 39, 64, 0.12);
  --shadow-hover: 0 20px 48px rgba(14, 39, 64, 0.18);
  --radius-lg: 28px;
  --radius-md: 20px;
  --radius-sm: 14px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  background-image:
    radial-gradient(140% 90% at 10% 10%, rgba(116, 224, 221, 0.28), transparent 60%),
    radial-gradient(120% 80% at 90% 0%, rgba(30, 155, 215, 0.18), transparent 70%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.6), transparent 40%);
  background-attachment: fixed;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

main {
  display: flex;
  flex-direction: column;
  gap: 80px;
  padding: 0 0 80px;
}

.container {
  width: min(1100px, 100%);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--color-surface-alt) 80%, transparent);
  backdrop-filter: blur(12px) saturate(140%);
  border-bottom: 1px solid color-mix(in srgb, var(--color-text) 8%, transparent);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 18px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 16px;
  text-decoration: none;
  color: inherit;
}

.brand__mark {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 35% 30%, rgba(255, 255, 255, 0.95), rgba(255, 255, 255, 0) 60%),
    radial-gradient(circle at 70% 75%, rgba(116, 224, 221, 0.7), transparent 70%),
    linear-gradient(135deg, rgba(30, 155, 215, 0.9), rgba(17, 106, 154, 0.9));
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.5);
  position: relative;
}

.brand__mark::after {
  content: "";
  position: absolute;
  inset: 12px;
  border-radius: 60% 40% 60% 40%;
  background: rgba(255, 255, 255, 0.85);
  transform: rotate(-12deg);
  opacity: 0.8;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand__title {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 0.02em;
}

.brand__tagline {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.primary-nav {
  display: none;
  align-items: center;
  gap: 20px;
  font-size: 0.95rem;
}

.primary-nav a {
  color: var(--color-muted);
  text-decoration: none;
  position: relative;
  padding-block: 4px;
  transition: color 0.2s ease;
}

.primary-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  border-radius: 999px;
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.2s ease, background 0.2s ease;
  background: linear-gradient(90deg, var(--color-accent), var(--color-highlight));
}

.primary-nav a:hover,
.primary-nav a:focus-visible {
  color: var(--color-accent-strong);
}

.primary-nav a:hover::after,
.primary-nav a:focus-visible::after {
  transform: scaleX(1);
}

/* Hero */
.hero {
  position: relative;
  padding: 120px 0 110px;
  overflow: hidden;
}

.hero__background {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(135deg, rgba(14, 39, 64, 0.78), rgba(14, 39, 64, 0.35)),
    url('../Banner.jpg');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.hero__content {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.hero__text {
  max-width: 520px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  color: var(--color-surface);
  text-shadow: 0 18px 40px rgba(6, 31, 48, 0.35);
}

.hero__eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.24em;
  font-size: 0.8rem;
  font-weight: 600;
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.4rem, 6vw, 3.8rem);
  line-height: 1.05;
}

.hero__lead {
  margin: 0;
  font-size: 1.08rem;
  color: rgba(255, 255, 255, 0.85);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.button {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
  padding: 14px 26px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.button--primary {
  color: #ffffff;
  background: linear-gradient(120deg, var(--color-accent), var(--color-highlight));
  box-shadow: 0 12px 30px rgba(14, 39, 64, 0.24);
}

.button--ghost {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.6);
  text-shadow: 0 8px 20px rgba(14, 39, 64, 0.24);
}

.button--primary:hover,
.button--primary:focus-visible,
.button--ghost:hover,
.button--ghost:focus-visible {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

.button--ghost:hover,
.button--ghost:focus-visible {
  background: rgba(255, 255, 255, 0.24);
  border-color: rgba(255, 255, 255, 0.8);
}

.hero__badge {
  align-self: flex-start;
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 18px;
  background: rgba(255, 255, 255, 0.88);
  color: var(--color-text);
  padding: 20px 24px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
}

.badge__play {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent), var(--color-highlight));
  border: none;
  color: rgba(255, 255, 255, 0.92);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
  box-shadow: 0 10px 24px rgba(14, 39, 64, 0.25);
  margin-top: auto;
  margin-bottom: auto;
}

.badge__play svg {
  width: 26px;
  height: 26px;
  display: block;
}

.badge__play:hover,
.badge__play:focus-visible {
  transform: translateY(-2px) scale(1.02);
  box-shadow: var(--shadow-hover);
}

.badge__play:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.85);
  outline-offset: 3px;
}

.hero__badge audio {
  display: none;
}

.badge__label {
  margin: 0;
  font-weight: 600;
  font-size: 0.95rem;
}

.badge__detail {
  margin: 4px 0 0;
  font-size: 0.9rem;
  color: var(--color-muted);
}

/* Gateway section */
.gateway {
  position: relative;
}

.section-header {
  display: flex;
  flex-direction: column;
  gap: 12px;
  text-align: left;
  margin-bottom: 36px;
}

.section-header h2 {
  margin: 0;
  font-size: clamp(1.8rem, 3.4vw, 2.4rem);
}

.section-header p {
  margin: 0;
  color: var(--color-muted);
  max-width: 640px;
}

.tile-grid {
  display: grid;
  gap: 24px;
}

.tile {
  display: block;
  text-decoration: none;
  background: var(--color-surface);
  color: inherit;
  padding: 32px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  position: relative;
  overflow: hidden;
}

.tile::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 80% 0%, rgba(30, 155, 215, 0.1), transparent 55%);
  pointer-events: none;
}

.tile--education::after {
  background: radial-gradient(circle at 80% 0%, rgba(116, 224, 221, 0.18), transparent 60%);
}

.tile--games::after {
  background: radial-gradient(circle at 75% 0%, rgba(30, 155, 215, 0.22), transparent 65%);
}

.tile:hover,
.tile:focus-visible {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.tile__icon {
  width: 72px;
  height: 72px;
  border-radius: 20px;
  background: rgba(30, 155, 215, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent-strong);
  margin-bottom: 20px;
}

.tile--education .tile__icon {
  background: rgba(116, 224, 221, 0.18);
}

.tile h3 {
  margin: 0 0 12px;
  font-size: 1.4rem;
}

.tile p {
  margin: 0 0 20px;
  color: var(--color-muted);
  font-size: 0.98rem;
}

.tile__cta {
  font-weight: 600;
  color: var(--color-accent-strong);
}

.tile[aria-disabled="true"] {
  pointer-events: none;
  opacity: 0.65;
}

/* Echolocation lesson block */
.section-eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-accent-strong);
}

.echolocation,
.sensory-anatomy,
.environmental-challenges {
  padding: 72px 0;
}

.echolocation {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(116, 224, 221, 0.12));
}

.echolocation-steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.step-card {
  position: relative;
  display: grid;
  gap: 18px;
  padding: 28px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
  height: 100%;
}

.step-card img {
  width: 92px;
  height: auto;
}

.step-card__body h3 {
  margin: 0 0 8px;
  font-size: 1.2rem;
}

.step-card__body p {
  margin: 0;
  color: var(--color-muted);
}

.step-card__number {
  position: absolute;
  top: 24px;
  right: 24px;
  font-size: 2rem;
  font-weight: 700;
  color: color-mix(in srgb, var(--color-accent-strong) 65%, transparent);
}

.echolocation .section-header {
  grid-area: header;
}

.echolocation-steps {
  grid-area: steps;
}

.echolocation .mini-reflection {
  grid-area: reflection;
}

.echolocation .quick-facts {
  grid-area: facts;
}

.mini-reflection {
  margin: 40px 0 0;
  padding: 24px 28px;
  border-radius: var(--radius-md);
  background: color-mix(in srgb, var(--color-highlight) 28%, rgba(255, 255, 255, 0.92));
  border-left: 6px solid var(--color-accent-strong);
  box-shadow: var(--shadow-soft);
}

.mini-reflection h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
}

.mini-reflection p {
  margin: 0;
  color: var(--color-text);
  font-weight: 500;
}

.quick-facts {
  margin: 40px 0 0;
  padding: 28px;
  border-radius: var(--radius-md);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
  display: grid;
  gap: 18px;
}

.quick-facts h3 {
  margin: 0;
  font-size: 1.1rem;
}

.quick-facts ul {
  margin: 0;
  padding-left: 22px;
  display: grid;
  gap: 8px;
  color: var(--color-muted);
  font-size: 0.98rem;
}

/* Sensory anatomy */
.sensory-anatomy {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.85), rgba(30, 155, 215, 0.08));
}

.anatomy-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.anatomy-card {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-soft);
  display: grid;
  gap: 20px;
  height: 100%;
}

.anatomy-card img {
  width: 88px;
  height: auto;
}

.anatomy-card__body h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.anatomy-card__body p {
  margin: 0;
  color: var(--color-muted);
}

.sensory-anatomy .section-header {
  grid-area: header;
}

.anatomy-grid {
  grid-area: grid;
}

.sensory-anatomy .mini-reflection {
  grid-area: reflection;
}

.sensory-anatomy .quick-facts {
  grid-area: facts;
}

/* Environmental challenges */
.environmental-challenges {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(14, 39, 64, 0.08));
}

.challenge-layout {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.challenge-card {
  display: grid;
  gap: 20px;
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: 26px;
  box-shadow: var(--shadow-soft);
  height: 100%;
}

.challenge-card img {
  width: 88px;
  height: auto;
}

.challenge-card__body h3 {
  margin: 0 0 8px;
  font-size: 1.18rem;
}

.challenge-card__body p {
  margin: 0;
  color: var(--color-muted);
}

.environmental-challenges .section-header {
  grid-area: header;
}

.challenge-layout {
  grid-area: grid;
}

.environmental-challenges .mini-reflection {
  grid-area: reflection;
}

.environmental-challenges .quick-facts {
  grid-area: facts;
}

/* Facts section */
.facts {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.9), rgba(116, 224, 221, 0.15));
  padding: 72px 0;
}

.facts__grid {
  display: grid;
  gap: 24px;
}

.info-card {
  background: var(--color-surface);
  border-radius: var(--radius-md);
  padding: 28px;
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  gap: 16px;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.info-card:hover,
.info-card:focus-within {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.info-card__icon {
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background: rgba(30, 155, 215, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-accent-strong);
}

.info-card h3 {
  margin: 0;
  font-size: 1.2rem;
}

.info-card p {
  margin: 0;
  color: var(--color-muted);
}

/* Learn page */
.learn-hero {
  padding: 140px 0 80px;
}

.learn-hero__inner {
  display: grid;
  gap: 36px;
  align-items: start;
}

.learn-hero__content {
  display: grid;
  gap: 20px;
  max-width: 560px;
}

.learn-hero__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-accent-strong);
}

.learn-hero__lead {
  margin: 0;
  font-size: 1.15rem;
  color: var(--color-muted);
}

.learn-hero__cta {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 10px;
}

.learn-hero__primary {
  padding-inline: 26px;
}

.learn-hero__microcopy {
  margin: 0;
  font-size: 0.95rem;
  color: color-mix(in srgb, var(--color-muted) 80%, transparent);
}

.lesson-hero {
  padding: 140px 0 80px;
}

.lesson-hero__inner {
  display: grid;
  gap: 28px;
}

.lesson-hero__copy {
  display: grid;
  gap: 18px;
  max-width: 640px;
}

.lesson-hero__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-accent-strong);
}

.lesson-hero__copy h1 {
  margin: 0;
  font-size: clamp(2.2rem, 4.8vw, 3rem);
  line-height: 1.08;
}

.lesson-hero__lead {
  margin: 0;
  font-size: 1.1rem;
  color: var(--color-muted);
}

.lesson-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.lesson-hero .button--ghost {
  color: var(--color-accent-strong);
  background: color-mix(in srgb, var(--color-accent) 10%, white 90%);
  border: 1px solid color-mix(in srgb, var(--color-accent) 30%, transparent);
  text-shadow: none;
}

.lesson-hero .button--ghost:hover,
.lesson-hero .button--ghost:focus-visible {
  background: color-mix(in srgb, var(--color-accent) 16%, white 84%);
  border-color: color-mix(in srgb, var(--color-accent) 45%, transparent);
}

.learn-hero__panel {
  display: grid;
  gap: 16px;
  padding: 28px;
  border-radius: var(--radius-lg);
  border: 1px solid color-mix(in srgb, var(--color-text) 10%, transparent);
  background: var(--color-surface);
  box-shadow: 0 18px 36px rgba(14, 39, 64, 0.08);
  min-width: 0;
}

.learn-hero__panel-heading {
  margin: 0;
  font-weight: 600;
  font-size: 1rem;
  color: var(--color-text);
}

.learn-hero__chip-row {
  display: flex;
  gap: 12px;
  overflow-x: auto;
  padding-bottom: 6px;
  scroll-snap-type: x proximity;
}

.learn-hero__chip-row::-webkit-scrollbar {
  height: 6px;
}

.learn-hero__chip-row::-webkit-scrollbar-thumb {
  background: rgba(14, 39, 64, 0.18);
  border-radius: 999px;
}

.chip {
  border: 1px solid color-mix(in srgb, var(--color-accent) 45%, white 55%);
  border-radius: 999px;
  padding: 9px 18px;
  font: inherit;
  background: color-mix(in srgb, var(--color-accent) 8%, white 92%);
  color: var(--color-accent-strong);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;
  scroll-snap-align: start;
  white-space: nowrap;
}

.chip:hover,
.chip:focus-visible {
  background: color-mix(in srgb, var(--color-accent) 20%, white 80%);
  transform: translateY(-1px);
}

.chip.is-active {
  background: var(--color-accent-strong);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 12px 24px rgba(17, 106, 154, 0.24);
}

.chip.is-active:hover,
.chip.is-active:focus-visible {
  background: color-mix(in srgb, var(--color-accent-strong) 90%, white 10%);
}

.learn-hero__ask {
  display: grid;
  gap: 12px;
}

.learn-hero__ask-label {
  font-weight: 600;
  font-size: 0.95rem;
}

.learn-hero__ask-field {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid color-mix(in srgb, var(--color-text) 12%, transparent);
  background: var(--color-surface);
  box-shadow: 0 12px 24px rgba(17, 106, 154, 0.08);
}

.learn-hero__ask-field svg {
  width: 22px;
  height: 22px;
  color: var(--color-accent-strong);
  flex-shrink: 0;
}

.learn-hero__ask-field input {
  flex: 1;
  border: none;
  outline: none;
  font: inherit;
  color: inherit;
  background: transparent;
}

.learn-hero__ask-field input::placeholder {
  color: color-mix(in srgb, var(--color-muted) 60%, transparent);
}

.learn-hero__ask-submit {
  white-space: nowrap;
}

.learn-hero__ask-hint {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-muted);
}

.learn-hero__response {
  margin-top: 16px;
  padding: 16px;
  border-radius: var(--radius-sm);
  border: 1px solid color-mix(in srgb, var(--color-text) 10%, transparent);
  background: color-mix(in srgb, var(--color-accent) 8%, white 92%);
  display: grid;
  gap: 8px;
}

.learn-hero__response-label {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-accent-strong);
}

.learn-hero__response-question {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
}

.learn-hero__response-answer {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-muted);
}

.topics {
  padding: 0 0 100px;
}

.topics__intro {
  display: grid;
  gap: 16px;
  max-width: 640px;
  margin-bottom: 48px;
}

.topics__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-accent-strong);
}

.topic-grid {
  display: grid;
  gap: 28px;
}

.topic-card {
  display: flex;
  flex-direction: column;
  gap: 24px;
  border-radius: var(--radius-md);
  border: 1px solid color-mix(in srgb, var(--color-text) 8%, transparent);
  background: var(--color-surface);
  box-shadow: 0 12px 28px rgba(14, 39, 64, 0.08);
  padding: 28px;
  text-decoration: none;
  color: inherit;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  cursor: default;
}

.topic-card:hover,
.topic-card:focus-visible {
  transform: translateY(-6px);
  box-shadow: 0 20px 40px rgba(14, 39, 64, 0.14);
}

.topic-card__figure {
  position: relative;
  border-radius: var(--radius-sm);
  padding: 18px;
  background: linear-gradient(135deg, rgba(30, 155, 215, 0.18), rgba(116, 224, 221, 0.32));
  color: var(--color-accent-strong);
  display: grid;
  place-items: center;
  aspect-ratio: 3 / 2;
  overflow: hidden;
}

.topic-card:nth-of-type(2) .topic-card__figure {
  background: linear-gradient(135deg, rgba(17, 106, 154, 0.2), rgba(116, 224, 221, 0.28));
}

.topic-card:nth-of-type(3) .topic-card__figure {
  background: linear-gradient(135deg, rgba(30, 155, 215, 0.14), rgba(116, 224, 221, 0.36));
}

.topic-card:nth-of-type(4) .topic-card__figure {
  background: linear-gradient(135deg, rgba(14, 39, 64, 0.22), rgba(116, 224, 221, 0.26));
}

.topic-card:nth-of-type(5) .topic-card__figure {
  background: linear-gradient(135deg, rgba(30, 155, 215, 0.2), rgba(17, 106, 154, 0.3));
}

.topic-card__figure svg {
  width: 100%;
  height: auto;
  max-width: 220px;
}

.topic-card__badge {
  position: absolute;
  top: 14px;
  left: 14px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-accent-strong);
}

.topic-card__body {
  display: grid;
  gap: 16px;
}

.topic-card__body h3 {
  margin: 0;
  font-size: 1.3rem;
}

.topic-card__body p {
  margin: 0;
  color: var(--color-muted);
}

.topic-card__benefits {
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 6px;
  color: color-mix(in srgb, var(--color-text) 85%, transparent);
  font-size: 0.95rem;
}

.topic-card__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  font-size: 0.95rem;
  color: color-mix(in srgb, var(--color-muted) 90%, transparent);
}

.topic-card__status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.topic-card__status svg {
  width: 18px;
  height: 18px;
  color: var(--color-accent-strong);
}

.topic-card__status span {
  font-size: 0.9rem;
}

.topic-card__cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 22px;
  border-radius: 999px;
  background: var(--color-accent-strong);
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  width: fit-content;
}

.topic-card__cta::after {
  content: "\2192";
  font-size: 1.1em;
}

.topic-card__cta:hover,
.topic-card__cta:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(17, 106, 154, 0.32);
}

.topics__empty {
  margin-top: 32px;
  padding: 20px;
  border-radius: var(--radius-sm);
  border: 1px dashed color-mix(in srgb, var(--color-text) 16%, transparent);
  background: color-mix(in srgb, var(--color-surface) 70%, transparent);
  color: var(--color-muted);
  text-align: center;
}

.learn-path {
  padding: 0 0 100px;
}

.learn-path__inner {
  display: grid;
  gap: 28px;
  padding: 32px;
  border-radius: var(--radius-lg);
  border: 1px solid color-mix(in srgb, var(--color-text) 10%, transparent);
  background: linear-gradient(135deg, rgba(116, 224, 221, 0.14), rgba(30, 155, 215, 0.12));
}

.learn-path__header {
  display: grid;
  gap: 12px;
  max-width: 520px;
}

.learn-path__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-accent-strong);
}

.learn-path__header h2 {
  margin: 0;
}

.learn-path__header p {
  margin: 0;
  color: var(--color-muted);
}

.learn-path__steps {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 18px;
}

.learn-path__steps li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px;
  align-items: center;
  padding: 16px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.8);
  border: 1px solid rgba(14, 39, 64, 0.06);
}

.learn-path__step-number {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-accent-strong);
  color: #ffffff;
  font-weight: 600;
}

.learn-path__step-title {
  margin: 0;
  font-weight: 600;
}

.learn-path__step-desc {
  margin: 2px 0 0;
  color: var(--color-muted);
  font-size: 0.95rem;
}

.learn-path__summary {
  display: flex;
  flex-direction: column;
  gap: 12px;
  font-size: 0.95rem;
  color: var(--color-muted);
  grid-column: 1 / -1;
}

.learn-path__meter-track {
  display: block;
  width: 100%;
  height: 10px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(14, 39, 64, 0.1);
  overflow: hidden;
}

.learn-path__meter-fill {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-strong));
  transition: width 0.3s ease;
}

.learn-path__meter-caption {
  margin: 8px 0 0;
  font-size: 0.85rem;
  color: color-mix(in srgb, var(--color-muted) 80%, transparent);
}

.learn-quick {
  padding: 0 0 100px;
}

.learn-quick__inner {
  display: grid;
}

.learn-quick__tile {
  padding: 36px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(30, 155, 215, 0.18), rgba(17, 106, 154, 0.28));
  color: #ffffff;
  display: grid;
  gap: 16px;
  box-shadow: 0 20px 40px rgba(14, 39, 64, 0.18);
}

.learn-quick__label {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-weight: 600;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.8);
}

.learn-quick__tile h2 {
  margin: 0;
}

.learn-quick__tile p {
  margin: 0;
  color: rgba(255, 255, 255, 0.9);
}

.learn-quick__cta {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 24px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.18);
  color: #ffffff;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid rgba(255, 255, 255, 0.4);
  width: fit-content;
  transition: background 0.2s ease, transform 0.2s ease;
}

.learn-quick__cta::after {
  content: "\2192";
  font-size: 1.1em;
}

.learn-quick__cta:hover,
.learn-quick__cta:focus-visible {
  background: rgba(255, 255, 255, 0.28);
  transform: translateY(-2px);
}

.learn-support {
  padding: 0 0 100px;
}

.learn-support__inner {
  display: grid;
  gap: 32px;
}

.learn-support__header {
  display: grid;
  gap: 12px;
  max-width: 600px;
}

.learn-support__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--color-accent-strong);
}

.learn-support__header p {
  margin: 0;
  color: var(--color-muted);
}

.learn-support__grid {
  display: grid;
  gap: 24px;
}

.support-card {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 18px;
  padding: 24px;
  border-radius: var(--radius-md);
  border: 1px solid color-mix(in srgb, var(--color-text) 10%, transparent);
  background: var(--color-surface);
  text-decoration: none;
  color: inherit;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  box-shadow: 0 14px 30px rgba(14, 39, 64, 0.08);
}

.support-card:hover,
.support-card:focus-visible {
  transform: translateY(-4px);
  box-shadow: 0 20px 40px rgba(14, 39, 64, 0.12);
}

.support-card__icon {
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background: rgba(30, 155, 215, 0.12);
  display: grid;
  place-items: center;
  color: var(--color-accent-strong);
}

.support-card__icon svg {
  width: 30px;
  height: 30px;
}

.support-card__body {
  display: grid;
  gap: 8px;
}

.support-card__body h3 {
  margin: 0;
  font-size: 1.1rem;
}

.support-card__body p {
  margin: 0;
  color: var(--color-muted);
}

.learn-credibility {
  padding: 0 0 120px;
}

.learn-credibility__inner {
  border-radius: var(--radius-lg);
  border: 1px solid color-mix(in srgb, var(--color-text) 10%, transparent);
  background: rgba(255, 255, 255, 0.9);
  padding: 36px;
  display: grid;
  gap: 16px;
  text-align: center;
  box-shadow: 0 18px 36px rgba(14, 39, 64, 0.1);
}

.learn-credibility__stat {
  margin: 0;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--color-accent-strong);
}

.learn-credibility__quote {
  margin: 0;
  font-style: italic;
  color: var(--color-muted);
}

.learn-credibility__quote span {
  display: block;
  font-style: normal;
  margin-top: 6px;
  color: color-mix(in srgb, var(--color-text) 75%, transparent);
}

.learn-credibility__about {
  margin: 0;
  color: color-mix(in srgb, var(--color-text) 90%, transparent);
  font-size: 0.95rem;
}

[hidden] {
  display: none !important;
}

/* Footer */
.site-footer {
  padding: 48px 0 60px;
  background: var(--color-surface);
  border-top: 1px solid color-mix(in srgb, var(--color-text) 8%, transparent);
}

.footer__content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  text-align: center;
  color: var(--color-muted);
}

.footer__link {
  color: var(--color-accent-strong);
  text-decoration: none;
  font-weight: 600;
}

.footer__link:hover,
.footer__link:focus-visible {
  text-decoration: underline;
}

.footer__tagline {
  margin: 0;
}

/* Responsive */
@media (min-width: 640px) {
  .primary-nav {
    display: inline-flex;
  }

  .learn-hero__inner {
    grid-template-columns: minmax(0, 1fr) minmax(320px, 380px);
  }

  .topic-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .learn-path__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: start;
  }

  .learn-path__header {
    grid-column: 1 / 2;
  }

  .learn-path__steps {
    grid-column: 1 / -1;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .learn-path__steps li {
    height: 100%;
  }

  .learn-path__summary {
    grid-column: 2 / 3;
    align-self: end;
  }

  .learn-support__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .hero__content {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }

  .hero__badge {
    margin-top: 40px;
  }

  .tile-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .facts__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .anatomy-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .challenge-layout {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .topic-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .learn-support__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .learn-path__inner {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  }

  .learn-path__steps {
    grid-column: 1 / -1;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .echolocation > .container,
  .sensory-anatomy > .container,
  .environmental-challenges > .container {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    grid-template-rows: auto auto auto;
    gap: 48px 32px;
    align-items: start;
  }

  .echolocation > .container {
    grid-template-areas:
      "header header"
      "steps steps"
      "reflection facts";
  }

  .sensory-anatomy > .container {
    grid-template-areas:
      "header header"
      "grid grid"
      "reflection facts";
  }

  .environmental-challenges > .container {
    grid-template-areas:
      "header header"
      "grid grid"
      "reflection facts";
  }

  .echolocation-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .anatomy-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .echolocation .mini-reflection,
  .sensory-anatomy .mini-reflection,
  .environmental-challenges .mini-reflection,
  .echolocation .quick-facts,
  .sensory-anatomy .quick-facts,
  .environmental-challenges .quick-facts {
    margin-top: 0;
  }
}

@media (max-width: 639px) {
  body {
    background-attachment: scroll;
  }

  .site-header {
    position: static;
  }

  .hero {
    padding: 96px 0 80px;
  }

  .hero__badge {
    grid-template-columns: 1fr;
    text-align: left;
  }

  .learn-hero {
    padding: 110px 0 60px;
  }

  .learn-hero__panel {
    padding: 24px;
  }

  .lesson-hero {
    padding: 110px 0 60px;
  }

  .lesson-hero__actions {
    flex-direction: column;
    align-items: stretch;
  }

  .chip {
    padding: 9px 16px;
  }

  .topic-card {
    padding: 24px;
  }

  .support-card {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .button,
  .tile,
  .info-card {
    transition: none !important;
  }
}

/* Communication lesson page */
.lesson-hero {
  padding: 120px 0 80px;
}

.lesson-hero__inner {
  display: grid;
  gap: 40px;
  align-items: start;
}

.lesson-hero__content {
  display: flex;
  flex-direction: column;
  gap: 20px;
  background: color-mix(in srgb, var(--color-surface) 88%, rgba(116, 224, 221, 0.15));
  padding: 40px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
}

.lesson-hero__eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.78rem;
  color: var(--color-accent-strong);
  margin: 0;
}

.lesson-hero__lead {
  margin: 0;
  font-size: 1.1rem;
}

.lesson-hero__highlights {
  margin: 0;
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  color: var(--color-muted);
}

.lesson-hero__aside {
  background: linear-gradient(135deg, rgba(30, 155, 215, 0.12), rgba(116, 224, 221, 0.32));
  padding: 32px;
  border-radius: var(--radius-md);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.6);
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 420px;
}

.lesson-hero__aside-label {
  font-weight: 600;
  margin: 0;
  color: var(--color-accent-strong);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.75rem;
}

.lesson-hero__aside-text {
  margin: 0;
}

.experience-preview {
  padding: 40px 0 20px;
}

.experience-preview__inner {
  display: grid;
  gap: 40px;
  align-items: center;
}

.experience-preview__card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  padding: 40px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.experience-preview__eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-size: 0.75rem;
  color: var(--color-accent-strong);
  margin: 0;
}

.experience-preview__list {
  margin: 0;
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  color: var(--color-muted);
}

.experience-preview__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: center;
}

.experience-preview__link {
  color: var(--color-accent-strong);
  font-weight: 600;
  text-decoration: none;
}

.experience-preview__link:hover,
.experience-preview__link:focus-visible {
  text-decoration: underline;
}

.experience-preview__figure {
  position: relative;
  min-height: 280px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: linear-gradient(160deg, rgba(17, 106, 154, 0.9), rgba(116, 224, 221, 0.6));
  box-shadow: var(--shadow-soft);
}

.experience-preview__pulse {
  position: absolute;
  inset: 50% auto auto 50%;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.6);
  transform: translate(-50%, -50%);
  animation: sonarPulse 4s ease-in-out infinite;
}

.experience-preview__pulse--two {
  animation-delay: 1.2s;
  width: 180px;
  height: 180px;
}

.experience-preview__pulse--three {
  animation-delay: 2.4s;
  width: 240px;
  height: 240px;
}

.experience-preview__dolphin {
  position: absolute;
  inset: 55% auto auto 20%;
  width: 140px;
  height: 70px;
  border-radius: 50% 50% 40% 40%;
  background: rgba(255, 255, 255, 0.8);
  transform: rotate(-8deg);
  filter: drop-shadow(0 16px 24px rgba(6, 31, 48, 0.25));
}

@keyframes sonarPulse {
  0% {
    transform: translate(-50%, -50%) scale(0.6);
    opacity: 0.8;
  }
  70% {
    opacity: 0.1;
  }
  100% {
    transform: translate(-50%, -50%) scale(1.1);
    opacity: 0;
  }
}

.audio-lab {
  padding: 40px 0 60px;
}

.audio-lab__inner {
  display: flex;
  flex-direction: column;
  gap: 32px;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 48px;
  box-shadow: var(--shadow-soft);
}

.audio-lab__header {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.audio-lab__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  font-size: 0.75rem;
  color: var(--color-accent-strong);
}

.audio-comparison {
  display: grid;
  gap: 24px;
}

.audio-comparison__track {
  border: 1px solid color-mix(in srgb, var(--color-accent) 20%, transparent);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 16px;
  background: color-mix(in srgb, var(--color-surface) 92%, rgba(30, 155, 215, 0.12));
}

.audio-comparison__description {
  margin: 0;
  color: var(--color-muted);
}

.audio-toggle {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  border: none;
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-strong));
  color: #ffffff;
  font-weight: 600;
  padding: 12px 20px;
  border-radius: 999px;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.audio-toggle:hover,
.audio-toggle:focus-visible {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

.audio-toggle[aria-pressed='true'] {
  background: linear-gradient(135deg, var(--color-highlight), var(--color-accent));
  color: var(--color-text);
}

.audio-toggle__icon svg {
  width: 20px;
  height: 20px;
}

.audio-lab__note {
  margin: 0;
  color: var(--color-muted);
  font-size: 0.95rem;
}

.worksheet-callout {
  padding: 20px 0 120px;
}

.worksheet-callout__inner {
  display: grid;
  gap: 24px;
  align-items: center;
  background: linear-gradient(120deg, rgba(30, 155, 215, 0.14), rgba(116, 224, 221, 0.25));
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-soft);
}

.worksheet-callout__icon {
  width: 88px;
  height: 88px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--color-surface);
  color: var(--color-accent-strong);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.7);
}

.worksheet-callout__icon svg {
  width: 44px;
  height: 44px;
}

.worksheet-callout__content {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.worksheet-callout__eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.75rem;
  color: var(--color-accent-strong);
}

@media (min-width: 768px) {
  .lesson-hero__inner {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
  }

  .experience-preview__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .audio-comparison {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .worksheet-callout__inner {
    grid-template-columns: auto minmax(0, 1fr);
  }
}

@media (max-width: 600px) {
  .lesson-hero {
    padding-top: 90px;
  }

  .lesson-hero__content,
  .experience-preview__card,
  .audio-lab__inner,
  .worksheet-callout__inner {
    padding: 28px;
  }
}