/* ===========================================================================
   Kidwings design system
   ---------------------------------------------------------------------------
   Two surfaces, deliberately: "paper" for reading (lessons, prose, marketing)
   and "night" for the labs, because an owl lab should feel like dusk and a
   dark stage makes bone and feather photography read far better. Both are
   driven by the same token set, so a component can sit on either.
   ========================================================================= */

/* --- Tokens -------------------------------------------------------------- */
:root {
  /* Brand teal, sampled from the Kidwings wordmark. */
  --teal-900: #062f34;
  --teal-800: #0a464e;
  --teal-700: #0d6068;
  --teal-600: #10757f;
  --teal-500: #168d99;
  --teal-300: #6fc0c8;
  --teal-100: #d3ecef;

  /* Amber, sampled from Sherlock Bones' plumage. */
  --amber-600: #c96a1f;
  --amber-500: #e8883a;
  --amber-400: #f5a623;
  --amber-200: #fbd79a;
  --amber-100: #fdeed3;

  --paper: #fbf7f0;
  --paper-warm: #f5ede0;
  --white: #ffffff;
  --ink: #14241f;
  --ink-soft: #40544f;
  --ink-faint: #6e837d;
  --line: #e2dacb;

  --night-900: #05161a;
  --night-800: #0a2126;
  --night-700: #0f2f35;
  --night-600: #16424a;
  --night-line: #1d4e57;
  --night-text: #dcecee;
  --night-soft: #93b3b8;

  --good: #2f9e6b;
  --bad: #c4483f;

  /* Type */
  --display: "Fraunces", ui-serif, Georgia, serif;
  --sans: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, monospace;

  /* A 1.2 modular scale that shrinks gracefully on phones. */
  --step--1: clamp(0.83rem, 0.8rem + 0.15vw, 0.9rem);
  --step-0: clamp(1rem, 0.96rem + 0.2vw, 1.08rem);
  --step-1: clamp(1.2rem, 1.12rem + 0.4vw, 1.4rem);
  --step-2: clamp(1.45rem, 1.3rem + 0.75vw, 1.85rem);
  --step-3: clamp(1.75rem, 1.5rem + 1.25vw, 2.45rem);
  --step-4: clamp(2.1rem, 1.65rem + 2.2vw, 3.25rem);
  --step-5: clamp(2.5rem, 1.7rem + 3.6vw, 4.35rem);

  --sp-1: 0.35rem;
  --sp-2: 0.7rem;
  --sp-3: 1.1rem;
  --sp-4: 1.6rem;
  --sp-5: 2.4rem;
  --sp-6: 3.4rem;
  --sp-7: 5rem;

  --r-sm: 8px;
  --r-md: 14px;
  --r-lg: 22px;
  --r-xl: 32px;
  --r-pill: 999px;

  --shadow-sm: 0 1px 2px rgb(6 47 52 / 0.07), 0 2px 8px rgb(6 47 52 / 0.05);
  --shadow-md: 0 3px 6px rgb(6 47 52 / 0.07), 0 12px 28px rgb(6 47 52 / 0.09);
  --shadow-lg: 0 8px 18px rgb(6 47 52 / 0.1), 0 28px 60px rgb(6 47 52 / 0.14);

  --wrap: 1180px;
  --wrap-narrow: 760px;
  --nav-h: 72px;
}

/* --- Reset --------------------------------------------------------------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 1rem);
}

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: var(--step-0);
  line-height: 1.65;
  font-synthesis-weight: none;
  -webkit-font-smoothing: antialiased;
}

/* The UA rule is only `[hidden] { display: none }`, which any explicit
   `display` in this file outranks — `.btn` is inline-flex, so hiding a button
   with `el.hidden = true` silently did nothing. */
[hidden] { display: none !important; }

img, svg, video { max-width: 100%; height: auto; display: block; }
button, input, select, textarea { font: inherit; color: inherit; }
a { color: var(--teal-700); text-decoration-thickness: 1.5px; text-underline-offset: 2px; }
a:hover { color: var(--teal-600); }

h1, h2, h3, h4, h5 {
  font-family: var(--display);
  font-weight: 600;
  line-height: 1.1;
  margin: 0 0 0.5em;
  letter-spacing: -0.015em;
  font-variation-settings: "SOFT" 40, "WONK" 1;
}
h1 { font-size: var(--step-4); }
h2 { font-size: var(--step-3); }
h3 { font-size: var(--step-2); }
h4 { font-size: var(--step-1); }
p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }

:focus-visible {
  outline: 3px solid var(--amber-400);
  outline-offset: 2px;
  border-radius: 4px;
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip-path: inset(50%); white-space: nowrap; border: 0;
}

.skip-link {
  position: absolute; left: 50%; top: 0;
  transform: translate(-50%, -120%);
  z-index: 200; padding: 0.7rem 1.2rem;
  background: var(--teal-700); color: var(--white);
  border-radius: 0 0 var(--r-md) var(--r-md);
  font-weight: 600; text-decoration: none;
}
.skip-link:focus { transform: translate(-50%, 0); color: var(--white); }

/* --- Layout -------------------------------------------------------------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1.1rem, 4vw, 2.2rem);
}
.wrap--narrow { max-width: var(--wrap-narrow); }

.section { padding-block: var(--sp-7); }
.section--tight { padding-block: var(--sp-6); }
.section--paper { background: var(--paper-warm); }
.section--white { background: var(--white); }
.section--night { background: var(--night-900); color: var(--night-text); }
.section--night h2, .section--night h3 { color: var(--white); }

.stack > * + * { margin-top: var(--sp-3); }
.grid { display: grid; gap: var(--sp-4); }

/* --- Eyebrow / section heads --------------------------------------------- */
.eyebrow {
  display: inline-flex; align-items: center; gap: 0.5rem;
  font-family: var(--sans);
  font-size: var(--step--1);
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--teal-600);
  margin: 0 0 var(--sp-2);
}
.eyebrow::before {
  content: ""; width: 1.6rem; height: 2px;
  background: var(--amber-500); border-radius: 2px;
}
.section--night .eyebrow { color: var(--amber-400); }

.section-head { max-width: 62ch; margin-bottom: var(--sp-5); }
.section-head p { color: var(--ink-soft); font-size: var(--step-1); line-height: 1.55; }
.section--night .section-head p { color: var(--night-soft); }

.lede { font-size: var(--step-1); line-height: 1.55; color: var(--ink-soft); }

/* --- Buttons ------------------------------------------------------------- */
.btn {
  --btn-bg: var(--teal-700);
  --btn-fg: var(--white);
  display: inline-flex; align-items: center; justify-content: center;
  gap: 0.55rem;
  padding: 0.85rem 1.5rem;
  background: var(--btn-bg); color: var(--btn-fg);
  border: 2px solid transparent;
  border-radius: var(--r-pill);
  font-weight: 650; font-size: var(--step-0);
  text-decoration: none; cursor: pointer;
  transition: transform 0.16s ease, box-shadow 0.16s ease, background 0.16s ease;
  box-shadow: var(--shadow-sm);
}
.btn:hover {
  color: var(--btn-fg);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.btn:active { transform: translateY(0); }
.btn--amber { --btn-bg: var(--amber-500); --btn-fg: #3a1c04; }
.btn--ghost {
  --btn-bg: transparent; --btn-fg: var(--teal-700);
  border-color: currentColor; box-shadow: none;
}
.btn--ghost:hover { background: var(--teal-100); }
.btn--on-night {
  --btn-bg: transparent; --btn-fg: var(--night-text);
  border-color: var(--night-line); box-shadow: none;
}
.btn--on-night:hover { background: var(--night-700); }
.btn--lg { padding: 1rem 2rem; font-size: var(--step-1); }
.btn--sm { padding: 0.5rem 1rem; font-size: var(--step--1); }
.btn[disabled] { opacity: 0.45; pointer-events: none; }

/* --- Header -------------------------------------------------------------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(12px) saturate(1.4);
  border-bottom: 1px solid var(--line);
}
.site-header__inner {
  height: var(--nav-h);
  display: flex; align-items: center; gap: var(--sp-4);
}
.brand { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; margin-right: auto; }
.brand img { height: 34px; width: auto; }
.brand__tag {
  font-family: var(--display); font-size: 0.78rem; font-weight: 600;
  color: var(--ink-faint); border-left: 1px solid var(--line);
  padding-left: 0.6rem; line-height: 1.2; max-width: 9rem;
}

.nav { display: flex; align-items: center; gap: 0.3rem; }
.nav a {
  padding: 0.5rem 0.8rem; border-radius: var(--r-pill);
  color: var(--ink); text-decoration: none;
  font-weight: 550; font-size: 0.95rem;
  white-space: nowrap;
}
.nav a:hover { background: var(--teal-100); color: var(--teal-800); }
.nav a[aria-current] { background: var(--teal-700); color: var(--white); }

.nav-toggle {
  display: none; margin-left: auto;
  width: 44px; height: 44px; padding: 0;
  background: none; border: 1px solid var(--line);
  border-radius: var(--r-md); cursor: pointer;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  display: block; width: 18px; height: 2px; margin-inline: auto;
  background: var(--ink); border-radius: 2px; transition: transform 0.2s ease;
}
.nav-toggle span::before, .nav-toggle span::after { content: ""; position: relative; }
.nav-toggle span::before { top: -6px; }
.nav-toggle span::after { top: 4px; }

@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .nav {
    position: fixed; inset: var(--nav-h) 0 auto 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--paper); border-bottom: 1px solid var(--line);
    padding: var(--sp-2) var(--sp-3) var(--sp-4);
    box-shadow: var(--shadow-lg);
    max-height: calc(100dvh - var(--nav-h)); overflow: auto;
  }
  .nav[hidden] { display: none; }
  .nav a { padding: 0.8rem 0.9rem; border-radius: var(--r-md); font-size: 1.05rem; }
  .brand__tag { display: none; }
}

/* --- Hero ---------------------------------------------------------------- */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(120% 90% at 78% 8%, var(--teal-700) 0%, transparent 62%),
    linear-gradient(168deg, var(--night-800) 0%, var(--teal-900) 55%, #041f24 100%);
  color: var(--night-text);
  padding-block: clamp(var(--sp-6), 9vw, 7rem);
}
.hero::after {
  /* A soft scatter of "stars" for dusk, kept subtle. */
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background-image:
    radial-gradient(1.5px 1.5px at 12% 22%, rgb(255 255 255 / 0.5) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 82% 14%, rgb(255 255 255 / 0.35) 50%, transparent 51%),
    radial-gradient(1px 1px at 46% 8%, rgb(255 255 255 / 0.4) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 68% 62%, rgb(255 255 255 / 0.22) 50%, transparent 51%),
    radial-gradient(1px 1px at 26% 72%, rgb(255 255 255 / 0.25) 50%, transparent 51%),
    radial-gradient(1.5px 1.5px at 94% 44%, rgb(255 255 255 / 0.3) 50%, transparent 51%);
}
.hero__inner {
  position: relative; z-index: 1;
  display: grid; gap: var(--sp-5);
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  align-items: center;
}
.hero h1 { color: var(--white); font-size: var(--step-5); margin-bottom: var(--sp-3); }
.hero h1 em {
  font-style: normal; color: var(--amber-400);
  background: linear-gradient(180deg, transparent 62%, rgb(245 166 35 / 0.22) 62%);
}
.hero p { color: #bcd6d9; font-size: var(--step-1); max-width: 46ch; }
.hero__actions { display: flex; flex-wrap: wrap; gap: var(--sp-2); margin-top: var(--sp-4); }
.hero__art { position: relative; }
.hero__art img { width: 100%; filter: drop-shadow(0 26px 46px rgb(0 0 0 / 0.5)); }
.hero__stats {
  display: flex; flex-wrap: wrap; gap: var(--sp-4);
  margin-top: var(--sp-5); padding-top: var(--sp-4);
  border-top: 1px solid rgb(255 255 255 / 0.14);
}
.hero__stat strong {
  display: block; font-family: var(--display);
  font-size: var(--step-2); color: var(--amber-400); line-height: 1;
}
.hero__stat span { font-size: var(--step--1); color: var(--night-soft); }

@media (max-width: 860px) {
  .hero__inner { grid-template-columns: 1fr; gap: var(--sp-4); }
  /* Headline first on a phone. Leading with the full-width mascots pushed it
     below the fold entirely. */
  .hero__art { max-width: 260px; margin-inline: auto; }
  .hero p { max-width: none; }
  .hero__stats { gap: var(--sp-3); }
}

/* --- Cards --------------------------------------------------------------- */
.card {
  position: relative;
  display: flex; flex-direction: column;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}
.card--link:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--teal-300);
}
.card__media { position: relative; aspect-ratio: 16 / 10; background: var(--paper-warm); overflow: hidden; }
.card__media img { width: 100%; height: 100%; object-fit: cover; }
/* Specimen and diagram art: photographed on white, or transparent line art
   from the old site's GIFs. Either way it needs a light ground — on a dark
   one the foot diagrams disappear completely. */
.card__media--contain { background: var(--white); }
.card__media--contain img { object-fit: contain; padding: 0.9rem; }
.card__body { padding: var(--sp-3) var(--sp-3) var(--sp-4); display: flex; flex-direction: column; flex: 1; gap: 0.5rem; }
.card__body h3 { margin: 0; font-size: var(--step-1); }
.card__body p { color: var(--ink-soft); font-size: 0.95rem; margin: 0; }
.card__foot { margin-top: auto; padding-top: var(--sp-2); }
.card a.card__hit { position: absolute; inset: 0; z-index: 2; }
.card a.card__hit span { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); }

/* Numbered lesson cards */
.lesson-card__num {
  position: absolute; top: 0.8rem; left: 0.8rem; z-index: 1;
  display: grid; place-items: center;
  width: 2.3rem; height: 2.3rem;
  background: var(--amber-400); color: #3a1c04;
  border-radius: var(--r-pill);
  font-family: var(--display); font-weight: 700; font-size: 1rem;
  box-shadow: 0 2px 8px rgb(0 0 0 / 0.25);
}

/* --- Badges -------------------------------------------------------------- */
.badge {
  display: inline-flex; align-items: center; gap: 0.35rem;
  padding: 0.25rem 0.65rem;
  border-radius: var(--r-pill);
  font-size: 0.74rem; font-weight: 700;
  letter-spacing: 0.05em; text-transform: uppercase;
  background: var(--teal-100); color: var(--teal-800);
  white-space: nowrap;
}
.badge--play { background: var(--amber-100); color: var(--amber-600); }
.badge--read { background: var(--teal-100); color: var(--teal-800); }
.badge--night { background: var(--night-700); color: var(--teal-300); }
.badge-row { display: flex; flex-wrap: wrap; gap: 0.4rem; }

/* --- Grid helpers -------------------------------------------------------- */
.cards-3 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 290px), 1fr)); }
.cards-4 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 230px), 1fr)); }
.cards-2 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 400px), 1fr)); }

/* --- Prose (lesson bodies) ---------------------------------------------- */
.prose { max-width: 68ch; }
.prose > * + * { margin-top: 1.1em; }
.prose h2 { margin-top: 2.2em; font-size: var(--step-2); }
.prose h3 { margin-top: 1.8em; font-size: var(--step-1); }
.prose h2:first-child, .prose h3:first-child { margin-top: 0; }
.prose ul, .prose ol { padding-left: 1.3em; }
.prose li + li { margin-top: 0.4em; }
.prose figure { margin: 2em 0; }
.prose figure img { border-radius: var(--r-md); box-shadow: var(--shadow-sm); }
.prose figcaption {
  margin-top: 0.6rem; font-size: var(--step--1);
  color: var(--ink-faint); font-style: italic;
}
.prose blockquote {
  margin: 2em 0; padding: 1.2rem 1.5rem;
  background: var(--white); border-left: 4px solid var(--amber-400);
  border-radius: 0 var(--r-md) var(--r-md) 0;
  font-size: var(--step-1); font-family: var(--display);
}

/* Callout */
.callout {
  padding: var(--sp-3) var(--sp-4);
  background: var(--teal-100);
  border: 1px solid color-mix(in srgb, var(--teal-300) 60%, transparent);
  border-radius: var(--r-md);
}
.callout--amber { background: var(--amber-100); border-color: var(--amber-200); }
.callout h4 { margin-bottom: 0.3em; }
.callout p { color: var(--ink-soft); margin: 0; }

/* --- Footer -------------------------------------------------------------- */
.site-footer {
  background: var(--night-900); color: var(--night-soft);
  padding-block: var(--sp-6) var(--sp-4);
}
.site-footer a { color: var(--night-text); text-decoration: none; }
.site-footer a:hover { color: var(--amber-400); text-decoration: underline; }
.footer-grid {
  display: grid; gap: var(--sp-5);
  grid-template-columns: minmax(0, 1.4fr) repeat(auto-fit, minmax(150px, 1fr));
}
.footer-grid h4 {
  color: var(--white); font-size: 0.82rem; font-family: var(--sans);
  text-transform: uppercase; letter-spacing: 0.09em; margin-bottom: 0.9em;
}
.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li + li { margin-top: 0.5em; }
.footer-brand img { height: 38px; margin-bottom: var(--sp-2); }
.footer-note {
  margin-top: var(--sp-5); padding-top: var(--sp-3);
  border-top: 1px solid var(--night-line);
  display: flex; flex-wrap: wrap; gap: var(--sp-3);
  justify-content: space-between; font-size: var(--step--1);
}

/* --- Page header (interior pages) --------------------------------------- */
.page-head {
  background: linear-gradient(168deg, var(--night-800), var(--teal-900));
  color: var(--night-text);
  padding-block: var(--sp-6) var(--sp-6);
}
.page-head h1 { color: var(--white); margin-bottom: var(--sp-2); }
.page-head p { color: #b6d2d5; max-width: 60ch; font-size: var(--step-1); }

.crumbs {
  display: flex; flex-wrap: wrap; gap: 0.4rem;
  list-style: none; margin: 0 0 var(--sp-3); padding: 0;
  font-size: var(--step--1); color: var(--teal-300);
}
.crumbs a { color: var(--teal-300); text-decoration: none; }
.crumbs a:hover { color: var(--white); text-decoration: underline; }
.crumbs li + li::before { content: "/"; margin-right: 0.4rem; opacity: 0.5; }

/* --- Lesson chrome ------------------------------------------------------- */
.lesson-layout {
  display: grid; gap: var(--sp-5);
  grid-template-columns: minmax(0, 1fr) 260px;
  align-items: start;
}
@media (max-width: 1000px) {
  .lesson-layout { grid-template-columns: 1fr; }
  .lesson-aside { order: -1; }
}

.lesson-aside {
  position: sticky; top: calc(var(--nav-h) + 1rem);
  background: var(--white); border: 1px solid var(--line);
  border-radius: var(--r-lg); padding: var(--sp-3);
  box-shadow: var(--shadow-sm);
}
.lesson-aside h4 {
  font-family: var(--sans); font-size: 0.76rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.09em;
  color: var(--ink-faint); margin-bottom: 0.8em;
}
.lesson-nav { list-style: none; margin: 0; padding: 0; font-size: 0.9rem; }
.lesson-nav li + li { margin-top: 1px; }
.lesson-nav a {
  display: flex; gap: 0.55rem; align-items: baseline;
  padding: 0.45rem 0.6rem; border-radius: var(--r-sm);
  text-decoration: none; color: var(--ink-soft);
}
.lesson-nav a:hover { background: var(--paper-warm); color: var(--teal-800); }
.lesson-nav a[aria-current] { background: var(--teal-700); color: var(--white); font-weight: 600; }
.lesson-nav b {
  font-variant-numeric: tabular-nums; font-weight: 700;
  opacity: 0.6; min-width: 1.3em;
}
.lesson-nav a[aria-current] b { opacity: 0.85; }

.lesson-pager {
  display: flex; flex-wrap: wrap; gap: var(--sp-3);
  justify-content: space-between;
  margin-top: var(--sp-6); padding-top: var(--sp-4);
  border-top: 1px solid var(--line);
}
.lesson-pager a { display: block; max-width: 22rem; text-decoration: none; }
.lesson-pager span {
  display: block; font-size: var(--step--1); color: var(--ink-faint);
  text-transform: uppercase; letter-spacing: 0.08em; font-weight: 700;
}
.lesson-pager strong { font-family: var(--display); font-size: var(--step-1); color: var(--teal-800); }
.lesson-pager a:hover strong { color: var(--amber-600); }
.lesson-pager > :only-child:last-child { margin-left: auto; text-align: right; }

/* --- Generic gallery ----------------------------------------------------- */
.tiles { display: grid; gap: var(--sp-3); grid-template-columns: repeat(auto-fill, minmax(min(100%, 190px), 1fr)); }
.tile {
  background: var(--white); border: 1px solid var(--line);
  border-radius: var(--r-md); overflow: hidden; text-align: center;
  box-shadow: var(--shadow-sm);
}
.tile img { width: 100%; aspect-ratio: 4/3; object-fit: contain; background: var(--paper-warm); padding: 0.5rem; }
.tile figcaption { padding: 0.6rem; font-size: 0.88rem; font-weight: 600; }

/* --- Download strip ------------------------------------------------------ */
.downloads { display: grid; gap: var(--sp-2); grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr)); }
.download {
  display: flex; align-items: center; gap: 0.8rem;
  padding: 0.9rem 1.1rem;
  background: var(--white); border: 1px solid var(--line);
  border-radius: var(--r-md); text-decoration: none;
  box-shadow: var(--shadow-sm);
}
.download:hover { border-color: var(--amber-400); }
.download svg { flex: none; color: var(--amber-600); }
.download b { display: block; font-size: 0.95rem; color: var(--ink); }
.download span { font-size: var(--step--1); color: var(--ink-faint); }