/* ==========================================================================
   Anthropic Academy فارسی — main.css
   Design system v1.0 (DESIGN-SYSTEM.md)
   RTL-first Persian education site, Anthropic Learn–inspired.
   ========================================================================== */

/* ---------- @font-face: Vazirmatn ---------- */
@font-face {
  font-family: 'Vazirmatn';
  src: url('../assets/fonts/Vazirmatn-Light.ttf') format('truetype');
  font-weight: 300; font-style: normal; font-display: swap;
}
@font-face {
  font-family: 'Vazirmatn';
  src: url('../assets/fonts/Vazirmatn-Regular.ttf') format('truetype');
  font-weight: 400; font-style: normal; font-display: swap;
}
@font-face {
  font-family: 'Vazirmatn';
  src: url('../assets/fonts/Vazirmatn-Medium.ttf') format('truetype');
  font-weight: 500; font-style: normal; font-display: swap;
}
@font-face {
  font-family: 'Vazirmatn';
  src: url('../assets/fonts/Vazirmatn-Bold.ttf') format('truetype');
  font-weight: 700; font-style: normal; font-display: swap;
}

/* ---------- Design tokens ---------- */
:root {
  /* Brand primary (Anthropic Sienna / "Crail") */
  --aa-primary-500: #cc785c;
  --aa-primary-600: #b8624a;
  --aa-primary-700: #9c4f3a;
  --aa-primary-100: #f3d9cf;
  --aa-primary-50:  #faeee7;

  /* Background (Anthropic Cream) */
  --aa-bg-base:     #f5f4ef;
  --aa-bg-elevated: #ffffff;
  --aa-bg-subtle:   #ebe9e0;
  --aa-bg-code:     #1a1a1a;

  /* Text */
  --aa-text-primary:    #181818;
  --aa-text-secondary:  #4a4a4a;
  --aa-text-muted:      #7a7570;
  --aa-text-on-dark:    #f5f4ef;
  --aa-text-on-primary: #ffffff;

  /* Border / Divider */
  --aa-border-default: #d9d6cc;
  --aa-border-strong:  #b8b4a8;
  --aa-border-focus:   #cc785c;

  /* Semantic */
  --aa-success: #2f7d3a; --aa-success-bg: #e6f2e8;
  --aa-error:   #c0392b; --aa-error-bg:   #fbe8e6;
  --aa-warning: #c08020; --aa-warning-bg: #fdf3e0;
  --aa-info:    #2c6c9e; --aa-info-bg:    #e6eff6;

  /* Accent */
  --aa-accent-blue: #6b8eb0;
  --aa-accent-clay: #d4a27f;

  /* Fonts */
  --aa-font-sans: 'Vazirmatn', 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --aa-font-mono: 'JetBrains Mono', 'Menlo', 'SF Mono', 'Cascadia Code', ui-monospace, monospace;

  /* Spacing (4-base) */
  --aa-space-1:  4px;
  --aa-space-2:  8px;
  --aa-space-3:  12px;
  --aa-space-4:  16px;
  --aa-space-5:  24px;
  --aa-space-6:  32px;
  --aa-space-8:  48px;
  --aa-space-10: 64px;
  --aa-space-12: 96px;

  /* Radius */
  --aa-radius-none: 0;
  --aa-radius-sm:   4px;
  --aa-radius-md:   8px;
  --aa-radius-lg:   12px;
  --aa-radius-full: 9999px;

  /* Shadow */
  --aa-shadow-xs: 0 1px 2px rgba(24,24,24,0.04);
  --aa-shadow-sm: 0 1px 3px rgba(24,24,24,0.06), 0 1px 2px rgba(24,24,24,0.04);
  --aa-shadow-md: 0 4px 12px rgba(24,24,24,0.08);
  --aa-shadow-lg: 0 12px 32px rgba(24,24,24,0.12);
  --aa-shadow-focus: 0 0 0 3px rgba(204,120,92,0.35);

  /* Icon sizes */
  --aa-icon-sm: 16px;
  --aa-icon-md: 20px;
  --aa-icon-lg: 24px;
  --aa-icon-xl: 32px;

  /* Layout heights */
  --aa-header-h: 64px;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html, body, h1, h2, h3, h4, h5, h6, p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; padding: 0; }
ul, ol { list-style: none; }
img, svg { max-width: 100%; height: auto; display: block; }
button { font: inherit; cursor: pointer; background: transparent; border: 0; color: inherit; }
a { color: inherit; text-decoration: none; }
input, select, textarea { font: inherit; color: inherit; }

/* ---------- Base typography ---------- */
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--aa-font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--aa-text-primary);
  background: var(--aa-bg-base);
  font-feature-settings: "ss01", "ss02";
  letter-spacing: 0;
  word-spacing: 0.02em;
  direction: rtl;
  text-align: start;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  letter-spacing: -0.01em;
  font-weight: 700;
  color: var(--aa-text-primary);
}
h1 { font-size: 2.25rem; font-weight: 700; }   /* 36px */
h2 { font-size: 1.75rem; font-weight: 700; }   /* 28px */
h3 { font-size: 1.375rem; font-weight: 600; }  /* 22px */
h4 { font-size: 1.125rem; font-weight: 600; }  /* 18px */
h5 { font-size: 1rem;     font-weight: 600; }
h6 { font-size: 0.875rem; font-weight: 600; }

p { margin: 0; }
small { font-size: 0.875rem; color: var(--aa-text-secondary); }

/* ---------- Layout primitives ---------- */
.aa-container        { max-width: 1200px; margin-inline: auto; padding-inline: var(--aa-space-5); }
.aa-container-prose  { max-width: 720px;  margin-inline: auto; padding-inline: var(--aa-space-5); }
.aa-container-narrow { max-width: 560px;  margin-inline: auto; padding-inline: var(--aa-space-5); }

.aa-stack > * + * { margin-block-start: var(--aa-space-4); }
.aa-stack-lg > * + * { margin-block-start: var(--aa-space-6); }

.aa-flex { display: flex; gap: var(--aa-space-3); }
.aa-flex--center { align-items: center; }
.aa-flex--between { justify-content: space-between; }

.aa-skip {
  position: absolute;
  inset-inline-start: -9999px;
  inset-block-start: 0;
  background: var(--aa-primary-500);
  color: var(--aa-text-on-primary);
  padding: var(--aa-space-3) var(--aa-space-4);
  z-index: 1000;
}
.aa-skip:focus { inset-inline-start: var(--aa-space-3); inset-block-start: var(--aa-space-3); }

/* ---------- Header ---------- */
.aa-header {
  position: sticky; top: 0; z-index: 50;
  height: var(--aa-header-h);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--aa-border-default);
}
.aa-header__inner {
  max-width: 1200px; margin-inline: auto;
  height: 100%;
  display: flex; align-items: center; justify-content: space-between;
  gap: var(--aa-space-5);
  padding-inline: var(--aa-space-5);
}
.aa-brand {
  display: inline-flex; align-items: center; gap: var(--aa-space-3);
  font-weight: 700; font-size: 1.0625rem;
  color: var(--aa-text-primary);
}
.aa-brand__mark {
  width: 24px; height: 24px;
  border-radius: var(--aa-radius-full);
  background: var(--aa-primary-500);
  display: inline-block;
}
.aa-nav { display: flex; align-items: center; gap: var(--aa-space-5); }
.aa-nav a {
  color: var(--aa-text-secondary);
  font-size: 0.9375rem;
  font-weight: 500;
  transition: color .15s ease;
}
.aa-nav a:hover, .aa-nav a[aria-current="page"] { color: var(--aa-primary-600); }
.aa-header__end { display: flex; align-items: center; gap: var(--aa-space-3); }

.aa-menu-toggle {
  display: none;
  width: 40px; height: 40px;
  align-items: center; justify-content: center;
  border-radius: var(--aa-radius-md);
}
.aa-menu-toggle:hover { background: var(--aa-bg-subtle); }

@media (max-width: 768px) {
  .aa-nav { display: none; }
  .aa-menu-toggle { display: inline-flex; }
  .aa-nav.is-open {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    position: absolute;
    inset-inline-end: var(--aa-space-3);
    inset-block-start: calc(var(--aa-header-h) + var(--aa-space-2));
    background: var(--aa-bg-elevated);
    border: 1px solid var(--aa-border-default);
    border-radius: var(--aa-radius-md);
    box-shadow: var(--aa-shadow-md);
    padding: var(--aa-space-3);
    gap: var(--aa-space-2);
    min-width: 200px;
  }
  .aa-nav.is-open a { padding: var(--aa-space-2) var(--aa-space-3); border-radius: var(--aa-radius-sm); }
}

/* ---------- Hero ---------- */
.aa-hero {
  padding-block: var(--aa-space-12) var(--aa-space-10);
  text-align: center;
}
.aa-hero__title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-block-end: var(--aa-space-5);
  color: var(--aa-text-primary);
}
.aa-hero__title .aa-accent { color: var(--aa-primary-600); }
.aa-hero__lead {
  font-size: 1.125rem;
  line-height: 1.75;
  color: var(--aa-text-secondary);
  max-width: 640px;
  margin-inline: auto;
  margin-block-end: var(--aa-space-6);
}
.aa-hero__cta { display: flex; gap: var(--aa-space-3); justify-content: center; flex-wrap: wrap; }

/* ---------- Buttons ---------- */
.aa-btn {
  display: inline-flex; align-items: center; gap: var(--aa-space-2);
  font-family: var(--aa-font-sans);
  font-weight: 500;
  font-size: 0.9375rem;
  padding: 10px 20px;
  border-radius: var(--aa-radius-md);
  border: 1px solid transparent;
  transition: all .15s ease;
  min-height: 40px;
  text-decoration: none;
  white-space: nowrap;
}
.aa-btn--primary {
  background: var(--aa-primary-500);
  color: var(--aa-text-on-primary);
}
.aa-btn--primary:hover { background: var(--aa-primary-600); }
.aa-btn--primary:active { background: var(--aa-primary-700); transform: translateY(1px); }
.aa-btn--secondary {
  background: transparent;
  border-color: var(--aa-border-strong);
  color: var(--aa-text-primary);
}
.aa-btn--secondary:hover { border-color: var(--aa-primary-500); color: var(--aa-primary-600); }
.aa-btn--ghost {
  background: transparent;
  color: var(--aa-text-secondary);
}
.aa-btn--ghost:hover { background: var(--aa-bg-subtle); color: var(--aa-text-primary); }
.aa-btn--danger {
  background: transparent;
  color: var(--aa-error);
  border-color: var(--aa-error);
}
.aa-btn--link {
  padding: 0; min-height: auto;
  background: transparent; color: var(--aa-primary-600);
  text-decoration: underline; text-underline-offset: 2px;
}
.aa-btn:focus-visible { outline: none; box-shadow: var(--aa-shadow-focus); }
.aa-btn[disabled], .aa-btn:disabled {
  opacity: 0.55; cursor: not-allowed;
  background: var(--aa-border-default); color: var(--aa-text-muted); border-color: transparent;
}
.aa-btn--block { width: 100%; justify-content: center; }

/* ---------- Section ---------- */
.aa-section { padding-block: var(--aa-space-10); }
.aa-section__head { margin-block-end: var(--aa-space-6); }
.aa-section__title { font-size: 1.75rem; }
.aa-section__sub   { color: var(--aa-text-secondary); margin-block-start: var(--aa-space-2); }

/* ---------- Card grid (catalog) ---------- */
.aa-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--aa-space-5);
}

/* ---------- Course Card ---------- */
.aa-course-card {
  display: flex; flex-direction: column;
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-md);
  padding: 0;
  overflow: hidden;
  transition: border-color .15s ease, transform .15s ease, box-shadow .15s ease;
  color: var(--aa-text-primary);
  text-decoration: none;
}
.aa-course-card:hover {
  border-color: var(--aa-primary-500);
  transform: translateY(-2px);
  box-shadow: var(--aa-shadow-md);
}
.aa-course-card__cover {
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, var(--aa-primary-100), var(--aa-bg-subtle));
  display: flex; align-items: center; justify-content: center;
  position: relative;
  border-bottom: 1px solid var(--aa-border-default);
}
.aa-course-card__cover-num {
  font-size: 3rem;
  font-weight: 800;
  color: var(--aa-primary-600);
  opacity: 0.85;
  line-height: 1;
}
.aa-course-card__body { padding: var(--aa-space-5); display: flex; flex-direction: column; gap: var(--aa-space-3); flex: 1; }
.aa-course-card__eyebrow { font-size: 0.75rem; color: var(--aa-text-muted); font-weight: 500; text-transform: uppercase; letter-spacing: 0.05em; }
.aa-course-card__title { font-size: 1.125rem; font-weight: 600; line-height: 1.4; }
.aa-course-card__desc  { color: var(--aa-text-secondary); font-size: 0.9375rem; flex: 1; }
.aa-course-card__meta {
  display: flex; gap: var(--aa-space-4);
  font-size: 0.8125rem; color: var(--aa-text-muted);
  border-top: 1px solid var(--aa-border-default);
  padding-block-start: var(--aa-space-3);
}
.aa-course-card__meta span { display: inline-flex; align-items: center; gap: var(--aa-space-1); }
.aa-course-card[data-state="completed"] .aa-course-card__cover-num { color: var(--aa-success); }
.aa-course-card[data-state="locked"]    { opacity: 0.6; pointer-events: none; }

/* ---------- Progress bar ---------- */
.aa-progress {
  height: 6px;
  background: var(--aa-bg-subtle);
  border-radius: var(--aa-radius-full);
  overflow: hidden;
  width: 100%;
}
.aa-progress__fill {
  height: 100%;
  background: var(--aa-primary-500);
  width: 0%;
  transition: width .4s ease;
}
.aa-progress--success .aa-progress__fill { background: var(--aa-success); }
.aa-progress-row { display: flex; align-items: center; gap: var(--aa-space-3); }
.aa-progress-row__label { font-size: 0.8125rem; color: var(--aa-text-muted); white-space: nowrap; }

/* Scroll-progress bar at top of long pages */
.aa-scroll-progress {
  position: sticky; top: var(--aa-header-h); z-index: 40;
  height: 3px;
  background: transparent;
}
.aa-scroll-progress__fill {
  height: 100%;
  background: var(--aa-primary-500);
  width: 0%;
  transition: width .15s linear;
}

/* ---------- Breadcrumb ---------- */
.aa-breadcrumb {
  display: flex; flex-wrap: wrap;
  gap: var(--aa-space-2);
  font-size: 0.875rem;
  color: var(--aa-text-muted);
  margin-block-end: var(--aa-space-5);
}
.aa-breadcrumb a { color: var(--aa-text-secondary); }
.aa-breadcrumb a:hover { color: var(--aa-primary-600); }
.aa-breadcrumb__sep { opacity: 0.6; }
.aa-breadcrumb__current { color: var(--aa-text-primary); font-weight: 500; }

/* ---------- Chapter overview ---------- */
.aa-chapter-hero {
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-lg);
  padding: var(--aa-space-6);
  margin-block-end: var(--aa-space-8);
}
.aa-chapter-hero__eyebrow { color: var(--aa-text-muted); font-weight: 500; font-size: 0.875rem; }
.aa-chapter-hero__title { font-size: clamp(1.75rem, 4vw, 2.25rem); margin-block: var(--aa-space-2) var(--aa-space-4); }
.aa-chapter-hero__lead  { font-size: 1.0625rem; color: var(--aa-text-secondary); margin-block-end: var(--aa-space-5); }
.aa-chapter-hero__meta {
  display: flex; gap: var(--aa-space-5); flex-wrap: wrap;
  color: var(--aa-text-muted); font-size: 0.875rem;
  margin-block-end: var(--aa-space-4);
}

/* Lesson list (chapter overview) */
.aa-lesson-list { display: flex; flex-direction: column; gap: var(--aa-space-2); }
.aa-lesson-item {
  display: flex; align-items: center; gap: var(--aa-space-4);
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-inline-start: 3px solid var(--aa-border-default);
  border-radius: var(--aa-radius-md);
  padding: var(--aa-space-4) var(--aa-space-5);
  color: var(--aa-text-primary);
  transition: border-color .15s ease, background .15s ease;
}
.aa-lesson-item:hover { border-color: var(--aa-primary-500); }
.aa-lesson-item__icon { flex-shrink: 0; width: 24px; height: 24px; color: var(--aa-text-muted); }
.aa-lesson-item__num  { color: var(--aa-text-muted); font-weight: 500; min-width: 2.5rem; }
.aa-lesson-item__title { flex: 1; font-weight: 500; }
.aa-lesson-item__meta { color: var(--aa-text-muted); font-size: 0.875rem; }
.aa-lesson-item[data-state="completed"] { border-inline-start-color: var(--aa-success); }
.aa-lesson-item[data-state="completed"] .aa-lesson-item__icon { color: var(--aa-success); }
.aa-lesson-item[data-state="active"]    { border-inline-start-color: var(--aa-primary-500); background: var(--aa-primary-50); }
.aa-lesson-item[data-state="active"]    .aa-lesson-item__title { font-weight: 600; }
.aa-lesson-item[data-state="locked"]    { opacity: 0.55; pointer-events: none; }
.aa-lesson-item--quiz {
  border-inline-start-color: var(--aa-accent-clay);
  background: var(--aa-primary-50);
}
.aa-lesson-item--quiz .aa-lesson-item__icon { color: var(--aa-primary-600); }

/* ---------- Lesson page layout ---------- */
.aa-lesson-layout {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: var(--aa-space-8);
  max-width: 1200px;
  margin-inline: auto;
  padding: var(--aa-space-6) var(--aa-space-5) var(--aa-space-10);
  align-items: start;
}
.aa-lesson-main { min-width: 0; max-width: 760px; }
.aa-lesson-sidebar {
  position: sticky; top: calc(var(--aa-header-h) + var(--aa-space-5));
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-md);
  padding: var(--aa-space-4);
  max-height: calc(100vh - var(--aa-header-h) - var(--aa-space-8));
  overflow-y: auto;
}
.aa-lesson-sidebar__title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--aa-text-muted);
  margin-block-end: var(--aa-space-3);
  font-weight: 600;
}
.aa-lesson-sidebar__list { display: flex; flex-direction: column; gap: var(--aa-space-1); }
.aa-lesson-sidebar__item {
  display: flex; align-items: center; gap: var(--aa-space-2);
  padding: var(--aa-space-2) var(--aa-space-3);
  border-radius: var(--aa-radius-sm);
  color: var(--aa-text-secondary);
  font-size: 0.875rem;
  border-inline-start: 3px solid transparent;
}
.aa-lesson-sidebar__item:hover { background: var(--aa-bg-subtle); color: var(--aa-text-primary); }
.aa-lesson-sidebar__item[aria-current="step"],
.aa-lesson-sidebar__item.is-active {
  background: var(--aa-primary-50);
  color: var(--aa-primary-700);
  border-inline-start-color: var(--aa-primary-500);
  font-weight: 600;
}
.aa-lesson-sidebar__item[data-state="completed"] { color: var(--aa-text-secondary); }
.aa-lesson-sidebar__item[data-state="completed"]::before { content: '✓'; color: var(--aa-success); margin-inline-end: var(--aa-space-1); }
.aa-lesson-sidebar__item[data-state="locked"] { opacity: 0.55; pointer-events: none; }
.aa-lesson-sidebar__progress { margin-block-start: var(--aa-space-4); padding-block-start: var(--aa-space-4); border-block-start: 1px solid var(--aa-border-default); }

@media (max-width: 1023px) {
  .aa-lesson-layout { grid-template-columns: 1fr; }
  .aa-lesson-sidebar {
    position: static;
    max-height: none;
    order: -1;
  }
}

/* ---------- Article (rendered Markdown) ---------- */
.aa-article {
  font-size: 1.0625rem;
  line-height: 1.75;
  color: var(--aa-text-primary);
}
.aa-article h1 { font-size: 2.25rem; line-height: 1.2; margin-block-end: var(--aa-space-5); }
.aa-article h2 { font-size: 1.625rem; margin-block: var(--aa-space-8) var(--aa-space-3); }
.aa-article h3 { font-size: 1.25rem; margin-block: var(--aa-space-6) var(--aa-space-3); }
.aa-article h4 { font-size: 1.0625rem; margin-block: var(--aa-space-5) var(--aa-space-2); }
.aa-article p  { margin-block: var(--aa-space-4); }
.aa-article ul, .aa-article ol {
  margin-block: var(--aa-space-4);
  padding-inline-start: var(--aa-space-5);
  list-style: disc inside;
}
.aa-article ol { list-style: decimal inside; }
.aa-article li { margin-block: var(--aa-space-2); }
.aa-article blockquote {
  border-inline-start: 4px solid var(--aa-primary-500);
  background: var(--aa-bg-subtle);
  margin-block: var(--aa-space-5);
  padding: var(--aa-space-4) var(--aa-space-5);
  border-radius: var(--aa-radius-md);
  color: var(--aa-text-secondary);
}
.aa-article hr { border: none; border-top: 1px solid var(--aa-border-default); margin-block: var(--aa-space-6); }
.aa-article a {
  color: var(--aa-primary-600);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.aa-article a:hover { color: var(--aa-primary-700); }
.aa-article table {
  width: 100%; border-collapse: collapse;
  margin-block: var(--aa-space-5);
  direction: rtl;
  font-size: 0.9375rem;
}
.aa-article th, .aa-article td {
  border: 1px solid var(--aa-border-default);
  padding: var(--aa-space-2) var(--aa-space-3);
  text-align: start;
}
.aa-article th { background: var(--aa-bg-subtle); font-weight: 600; }
.aa-article img { border-radius: var(--aa-radius-md); }

/* ---------- Code blocks (LTR within RTL) ---------- */
.aa-article code,
.aa-article pre,
.codehilite {
  font-family: var(--aa-font-mono);
  direction: ltr;
  unicode-bidi: isolate;
}
.aa-article :not(pre) > code {
  background: var(--aa-bg-subtle);
  padding: 0.1em 0.4em;
  border-radius: var(--aa-radius-sm);
  font-size: 0.92em;
  color: var(--aa-text-primary);
  font-weight: 500;
}
.aa-article pre,
.codehilite {
  background: var(--aa-bg-code);
  color: var(--aa-text-on-dark);
  padding: var(--aa-space-4) var(--aa-space-5);
  border-radius: var(--aa-radius-lg);
  overflow-x: auto;
  margin-block: var(--aa-space-5);
  font-size: 0.875rem;
  line-height: 1.65;
  text-align: left;
  position: relative;
  box-shadow: var(--aa-shadow-sm);
}
.aa-article pre code,
.codehilite pre code,
.codehilite code {
  background: transparent;
  padding: 0;
  color: inherit;
  font-weight: 400;
}
.aa-code-copy {
  position: absolute;
  inset-inline-end: 12px;
  inset-block-start: 12px;
  background: rgba(255,255,255,0.08);
  color: var(--aa-text-on-dark);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: var(--aa-radius-sm);
  padding: 4px 8px;
  font-size: 11px;
  cursor: pointer;
  font-family: var(--aa-font-sans);
  transition: background .15s ease;
}
.aa-code-copy:hover { background: rgba(255,255,255,0.18); }
.aa-code-copy.is-copied { background: var(--aa-success); border-color: var(--aa-success); }

/* Pygments token colors (terracotta-friendly dark) */
.codehilite .k, .codehilite .kd, .codehilite .kn { color: #ffb86c; }
.codehilite .s, .codehilite .s1, .codehilite .s2 { color: #f1fa8c; }
.codehilite .c, .codehilite .c1, .codehilite .cm { color: #6a9588; font-style: italic; }
.codehilite .nb { color: #8be9fd; }
.codehilite .nf { color: #50fa7b; }
.codehilite .nc { color: #ffb86c; }
.codehilite .mi, .codehilite .mf { color: #bd93f9; }
.codehilite .o, .codehilite .ow { color: #ff79c6; }

/* keep inline English terms tidy */
.aa-article :is(p, li, td, h1, h2, h3, h4) :is(em, b, strong, code) {
  unicode-bidi: isolate;
}

/* ---------- Callouts ---------- */
.aa-callout {
  display: flex;
  gap: var(--aa-space-3);
  padding: var(--aa-space-4) var(--aa-space-5);
  border-inline-start: 4px solid;
  border-radius: var(--aa-radius-md);
  margin-block: var(--aa-space-5);
}
.aa-callout__icon { flex-shrink: 0; width: 24px; height: 24px; }
.aa-callout__body { flex: 1; }
.aa-callout__body strong { display: block; margin-block-end: var(--aa-space-1); }
.aa-callout--info    { border-color: var(--aa-info);    background: var(--aa-info-bg); }
.aa-callout--info    .aa-callout__icon { color: var(--aa-info); }
.aa-callout--tip     { border-color: var(--aa-success); background: var(--aa-success-bg); }
.aa-callout--tip     .aa-callout__icon { color: var(--aa-success); }
.aa-callout--warning { border-color: var(--aa-warning); background: var(--aa-warning-bg); }
.aa-callout--warning .aa-callout__icon { color: var(--aa-warning); }
.aa-callout--danger  { border-color: var(--aa-error);   background: var(--aa-error-bg); }
.aa-callout--danger  .aa-callout__icon { color: var(--aa-error); }

/* ---------- Lesson nav (prev/next) ---------- */
.aa-lesson-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--aa-space-3);
  margin-block-start: var(--aa-space-8);
  padding-block-start: var(--aa-space-5);
  border-top: 1px solid var(--aa-border-default);
}
.aa-lesson-nav a {
  display: flex; flex-direction: column; gap: var(--aa-space-1);
  padding: var(--aa-space-4) var(--aa-space-5);
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-md);
  color: var(--aa-text-primary);
  transition: border-color .15s ease, transform .15s ease;
}
.aa-lesson-nav a:hover { border-color: var(--aa-primary-500); transform: translateY(-1px); }
.aa-lesson-nav a[data-dir="next"] { text-align: end; }
.aa-lesson-nav__label { font-size: 0.75rem; color: var(--aa-text-muted); text-transform: uppercase; letter-spacing: 0.05em; }
.aa-lesson-nav__title { font-weight: 600; font-size: 0.9375rem; }
.aa-lesson-nav__placeholder { /* keeps grid alignment when only one direction is available */ }

/* ---------- Quiz UI ---------- */
.aa-quiz-page { padding-block: var(--aa-space-8) var(--aa-space-10); }
.aa-quiz-header {
  text-align: center;
  margin-block-end: var(--aa-space-6);
}
.aa-quiz-header__eyebrow { color: var(--aa-text-muted); font-size: 0.875rem; font-weight: 500; }
.aa-quiz-header__title   { font-size: 1.75rem; margin-block: var(--aa-space-2) var(--aa-space-4); }
.aa-quiz-meta {
  display: flex; gap: var(--aa-space-5); flex-wrap: wrap; justify-content: center;
  color: var(--aa-text-muted); font-size: 0.875rem;
}
.aa-quiz-meta span { display: inline-flex; align-items: center; gap: var(--aa-space-1); }

.aa-quiz-progress {
  display: flex; align-items: center; gap: var(--aa-space-3);
  margin-block: var(--aa-space-5);
  font-size: 0.875rem;
  color: var(--aa-text-muted);
}
.aa-quiz-progress .aa-progress { flex: 1; }

.aa-question-card {
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-lg);
  padding: var(--aa-space-6);
  margin-block: var(--aa-space-5);
}
.aa-question-card__head {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 0.8125rem;
  color: var(--aa-text-muted);
  margin-block-end: var(--aa-space-3);
}
.aa-question-card__num { font-weight: 600; }
.aa-difficulty {
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 8px;
  border-radius: var(--aa-radius-full);
  font-weight: 600;
}
.aa-difficulty--easy   { background: var(--aa-success-bg); color: var(--aa-success); }
.aa-difficulty--medium { background: var(--aa-warning-bg); color: var(--aa-warning); }
.aa-difficulty--hard   { background: var(--aa-error-bg);   color: var(--aa-error); }

.aa-question-card__prompt {
  font-size: 1.125rem;
  line-height: 1.6;
  font-weight: 600;
  margin-block-end: var(--aa-space-4);
  color: var(--aa-text-primary);
}

.aa-options { display: flex; flex-direction: column; gap: var(--aa-space-2); }
.aa-option {
  display: flex; align-items: flex-start; gap: var(--aa-space-3);
  background: var(--aa-bg-base);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-md);
  padding: var(--aa-space-3) var(--aa-space-4);
  cursor: pointer;
  transition: background .15s ease, border-color .15s ease;
}
.aa-option:hover { border-color: var(--aa-primary-500); background: var(--aa-bg-elevated); }
.aa-option__indicator {
  flex-shrink: 0;
  width: 20px; height: 20px;
  border-radius: var(--aa-radius-full);
  border: 2px solid var(--aa-border-strong);
  margin-block-start: 2px;
  position: relative;
  background: var(--aa-bg-elevated);
}
.aa-option--checkbox .aa-option__indicator { border-radius: var(--aa-radius-sm); }
.aa-option__text { flex: 1; line-height: 1.6; }
.aa-option input { position: absolute; opacity: 0; pointer-events: none; }
.aa-option.is-selected { border-color: var(--aa-primary-500); background: var(--aa-primary-50); }
.aa-option.is-selected .aa-option__indicator { border-color: var(--aa-primary-500); background: var(--aa-primary-500); }
.aa-option.is-selected .aa-option__indicator::after {
  content: ''; position: absolute;
  inset: 4px; border-radius: inherit; background: var(--aa-bg-elevated);
}
.aa-option--checkbox.is-selected .aa-option__indicator::after {
  content: '✓'; color: var(--aa-text-on-primary);
  inset: 0; display: flex; align-items: center; justify-content: center;
  font-size: 14px; line-height: 1; background: transparent;
}
.aa-option.is-correct { border-color: var(--aa-success); background: var(--aa-success-bg); }
.aa-option.is-correct .aa-option__indicator { border-color: var(--aa-success); background: var(--aa-success); }
.aa-option.is-wrong   { border-color: var(--aa-error); background: var(--aa-error-bg); }
.aa-option.is-wrong   .aa-option__indicator { border-color: var(--aa-error); background: var(--aa-error); }

.aa-question-card__feedback {
  margin-block-start: var(--aa-space-4);
  padding: var(--aa-space-3) var(--aa-space-4);
  border-radius: var(--aa-radius-md);
  border-inline-start: 4px solid;
  font-size: 0.9375rem;
  line-height: 1.7;
}
.aa-question-card__feedback[data-state="correct"]   { border-color: var(--aa-success); background: var(--aa-success-bg); color: var(--aa-text-primary); }
.aa-question-card__feedback[data-state="incorrect"] { border-color: var(--aa-error);   background: var(--aa-error-bg);   color: var(--aa-text-primary); }
.aa-question-card__feedback strong { display: block; margin-block-end: var(--aa-space-1); }

.aa-quiz-actions {
  display: flex; gap: var(--aa-space-3); justify-content: center;
  margin-block-start: var(--aa-space-6);
  flex-wrap: wrap;
}

/* Score screen */
.aa-score {
  text-align: center;
  background: var(--aa-bg-elevated);
  border: 1px solid var(--aa-border-default);
  border-radius: var(--aa-radius-lg);
  padding: var(--aa-space-8) var(--aa-space-5);
  margin-block: var(--aa-space-6);
}
.aa-score__ring { width: 160px; height: 160px; margin-inline: auto; margin-block-end: var(--aa-space-5); }
.aa-score__ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.aa-score__ring-bg   { fill: none; stroke: var(--aa-bg-subtle); stroke-width: 10; }
.aa-score__ring-fill { fill: none; stroke: var(--aa-primary-500); stroke-width: 10; stroke-linecap: round; transition: stroke-dashoffset .8s ease; }
.aa-score--passed .aa-score__ring-fill { stroke: var(--aa-success); }
.aa-score__center {
  position: relative; margin-top: -110px; height: 0;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
}
.aa-score__pct { font-size: 1.75rem; font-weight: 800; color: var(--aa-text-primary); line-height: 1; }
.aa-score__frac { font-size: 0.875rem; color: var(--aa-text-muted); margin-top: 4px; }
.aa-score__title { font-size: 1.5rem; font-weight: 700; margin-block-end: var(--aa-space-2); }
.aa-score__sub { color: var(--aa-text-secondary); margin-block-end: var(--aa-space-5); }
.aa-score--passed .aa-score__title { color: var(--aa-success); }
.aa-score--failed .aa-score__title { color: var(--aa-error); }

/* ---------- Footer ---------- */
.aa-footer {
  background: var(--aa-bg-subtle);
  border-top: 1px solid var(--aa-border-default);
  color: var(--aa-text-secondary);
  font-size: 0.875rem;
  padding-block: var(--aa-space-6);
  margin-block-start: var(--aa-space-10);
}
.aa-footer__inner {
  max-width: 1200px; margin-inline: auto;
  padding-inline: var(--aa-space-5);
  display: flex; flex-wrap: wrap; gap: var(--aa-space-3);
  align-items: center; justify-content: space-between;
}
.aa-footer a { color: var(--aa-text-secondary); }
.aa-footer a:hover { color: var(--aa-primary-600); }
.aa-footer__links { display: flex; gap: var(--aa-space-4); flex-wrap: wrap; }
.aa-footer__credits { color: var(--aa-text-muted); }

/* ---------- Utility ---------- */
.ltr-num { direction: ltr; unicode-bidi: embed; font-feature-settings: "ss01" off, "ss02" off; }
.aa-icon { width: var(--aa-icon-md); height: var(--aa-icon-md); display: inline-block; vertical-align: middle; flex-shrink: 0; }
.aa-icon--sm { width: var(--aa-icon-sm); height: var(--aa-icon-sm); }
.aa-icon--lg { width: var(--aa-icon-lg); height: var(--aa-icon-lg); }
.aa-icon--mirror-rtl { transform: scaleX(-1); }
.aa-visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0);
  white-space: nowrap; border: 0;
}
.aa-mt-0  { margin-top: 0 !important; }
.aa-mt-3  { margin-top: var(--aa-space-3); }
.aa-mt-5  { margin-top: var(--aa-space-5); }
.aa-mb-3  { margin-bottom: var(--aa-space-3); }
.aa-mb-5  { margin-bottom: var(--aa-space-5); }
.aa-text-muted { color: var(--aa-text-muted); }
.aa-hide-mobile { /* default: visible */ }

/* ---------- Focus ---------- */
*:focus-visible {
  outline: 2px solid var(--aa-primary-500);
  outline-offset: 2px;
  border-radius: var(--aa-radius-sm);
}

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
  html { font-size: 15px; }
  .aa-section { padding-block: var(--aa-space-8); }
  .aa-hero { padding-block: var(--aa-space-8); }
  .aa-card-grid { grid-template-columns: 1fr; }
  .aa-lesson-nav { grid-template-columns: 1fr; }
  .aa-question-card { padding: var(--aa-space-4); }
  .aa-footer__inner { flex-direction: column; align-items: flex-start; }
}

/* ---------- Reduced motion ---------- */
@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;
  }
}

/* ---------- Print ---------- */
@media print {
  .aa-header, .aa-footer, .aa-lesson-sidebar,
  .aa-lesson-nav, .aa-scroll-progress, .aa-menu-toggle,
  .aa-code-copy, .aa-quiz-actions { display: none !important; }
  body { background: #fff; color: #000; }
  .aa-lesson-layout { display: block; padding: 0; }
  .aa-lesson-main { max-width: 100%; }
  .aa-article a { color: #000; text-decoration: underline; }
  .aa-article pre, .codehilite { background: #f5f5f5; color: #000; box-shadow: none; border: 1px solid #ccc; }
  .codehilite .k, .codehilite .s, .codehilite .c, .codehilite .nb,
  .codehilite .nf, .codehilite .mi, .codehilite .o { color: #000 !important; }
  h1, h2, h3 { page-break-after: avoid; }
  pre, blockquote, .aa-callout { page-break-inside: avoid; }
}


/* ---------- SVG illustrations (added 2026-04-29) ---------- */
.aa-hero__art {
  max-width: 720px;
  margin: 0 auto var(--aa-space-6);
  pointer-events: none;
}
.aa-hero__art img {
  width: 100%;
  height: auto;
  display: block;
}
@media (max-width: 640px) {
  .aa-hero__art { max-width: 88%; }
}

.aa-course-card__cover {
  /* keep existing 16/9 aspect, but let the SVG image fill it */
  background: #faeee7;
  position: relative;
}
.aa-course-card__cover-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.aa-course-card__cover-badge {
  position: absolute;
  inset-inline-start: var(--aa-space-3);
  inset-block-start: var(--aa-space-3);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 28px;
  height: 28px;
  padding-inline: 8px;
  border-radius: var(--aa-radius-full);
  background: var(--aa-bg-elevated);
  color: var(--aa-primary-600);
  font-size: 0.8125rem;
  font-weight: 700;
  border: 1px solid var(--aa-border-default);
  box-shadow: var(--aa-shadow-xs);
}
.aa-course-card[data-state="completed"] .aa-course-card__cover-badge {
  color: var(--aa-success);
  border-color: var(--aa-success);
}

/* Brand mark: replace solid circle with inline SVG container when --svg variant present */
.aa-brand__mark--svg {
  width: 28px;
  height: 28px;
  background: transparent;
  border-radius: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.aa-brand__mark--svg svg { display: block; }