/* =============================================================================
   Alon Livshitz Learn — single stylesheet for /learn/*

   Imports the design-system tokens, then defines the patterns used across
   the hub, course landing, lesson units, review, account, admin, and login
   pages. All four standalone scaffolds in Lectures/_templates/ and the six
   rendered Lesson Units inline copies of these tokens — this file is now
   the single source of truth for the prod /learn site.

   Companion docs: design-system/design-system.md · Lectures/LEARN-STRATEGY.md
   ============================================================================= */

@import url('/design-system/tokens/tokens.css');

:root {
  --max-prose: 760px;
  --container-learn: var(--container-xl);
}

/* ── Base ──────────────────────────────────────────────────────────────── */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--surface-canvas);
  color: var(--text-primary);
  line-height: var(--leading-relaxed);
  -webkit-font-smoothing: antialiased;
}
a { color: var(--text-link); text-decoration: none; transition: color var(--duration-fast) var(--easing-standard); }
a:hover { color: var(--text-link-hover); text-decoration: underline; text-decoration-thickness: 1px; }
:focus-visible { outline: none; box-shadow: var(--shadow-focus); border-radius: var(--radius-sm); }

/* ─────────────────────────────────────────────────────────────────────────
   Canonical components — Alon Livshitz Learn 2026
   Pill buttons, generous spacing, dark-hero confidence, single-color
   discipline (Ink, White, Signal Blue, Signal Soft).
   ─────────────────────────────────────────────────────────────────────── */

/* ── Button ────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  font-family: var(--font-body);
  font-weight: 600; font-size: 15px; letter-spacing: -0.005em;
  padding: 14px 28px;
  border-radius: 9999px;
  border: 1.5px solid transparent;
  cursor: pointer; min-height: 48px;
  text-decoration: none; line-height: 1; white-space: nowrap;
  transition:
    background var(--duration-fast) var(--easing-standard),
    color var(--duration-fast) var(--easing-standard),
    border-color var(--duration-fast) var(--easing-standard),
    box-shadow var(--duration-fast) var(--easing-standard),
    transform var(--duration-fast) var(--easing-standard);
}
.btn:focus-visible { outline: none; box-shadow: var(--shadow-focus); }
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }

.btn--primary    {
  background: var(--color-signal); color: var(--color-white);
  box-shadow: 0 6px 20px -6px rgba(37, 99, 235, 0.45);
}
.btn--primary:hover {
  background: var(--color-signal-hover); color: var(--color-white);
  box-shadow: 0 10px 28px -6px rgba(37, 99, 235, 0.55);
  transform: translateY(-1px);
}

.btn--secondary {
  background: transparent; color: var(--color-ink);
  border-color: var(--color-ink);
}
.btn--secondary:hover {
  background: var(--color-ink); color: var(--color-white);
  transform: translateY(-1px);
}

.btn--ghost { background: transparent; color: var(--color-signal); }
.btn--ghost:hover { background: var(--color-signal-soft); color: var(--color-signal-strong); }

.btn--on-dark {
  background: var(--color-white); color: var(--color-ink);
  box-shadow: 0 8px 24px -8px rgba(0, 0, 0, 0.35);
}
.btn--on-dark:hover {
  background: var(--color-slate-100); color: var(--color-ink);
  transform: translateY(-1px);
}

.btn--on-dark-outline {
  background: transparent; color: var(--color-white);
  border-color: rgba(255, 255, 255, 0.32);
}
.btn--on-dark-outline:hover {
  background: rgba(255, 255, 255, 0.08); color: var(--color-white);
  border-color: var(--color-white);
}

.btn--lg {
  padding: 18px 36px;
  font-size: 17px;
  min-height: 56px;
}
.btn--sm {
  padding: 9px 20px;
  font-size: 13px;
  min-height: 38px;
  font-weight: 600;
  letter-spacing: 0;
}

.btn--block { display: flex; width: 100%; }

/* ── Badge ─────────────────────────────────────────────────────────────── */
.badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 14px;
  background: var(--color-signal-soft); color: var(--color-signal-strong);
  font-size: 11px; font-weight: 700;
  border-radius: 9999px;
  text-transform: uppercase; letter-spacing: 0.12em;
}
.badge--strong { background: var(--color-signal-soft); color: var(--color-signal-strong); }
.badge--ink    { background: var(--color-ink); color: var(--color-white); }
.badge--on-dark {
  background: rgba(255, 255, 255, 0.1); color: var(--color-white);
  backdrop-filter: blur(8px);
}

/* ── Card ──────────────────────────────────────────────────────────────── */
.ds-card {
  position: relative;
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: 20px;
  padding: 36px;
  box-shadow:
    0 1px 2px rgba(15, 20, 25, 0.04),
    0 2px 8px -2px rgba(15, 20, 25, 0.04);
  transition:
    transform var(--duration-slow) var(--easing-standard),
    box-shadow var(--duration-slow) var(--easing-standard),
    border-color var(--duration-fast) var(--easing-standard);
  display: flex;
  flex-direction: column;
  gap: 16px;
  text-decoration: none;
  color: inherit;
}
a.ds-card:hover, .ds-card:hover {
  transform: translateY(-6px);
  box-shadow:
    0 24px 48px -16px rgba(15, 20, 25, 0.18),
    0 8px 16px -8px rgba(15, 20, 25, 0.08);
  border-color: rgba(37, 99, 235, 0.35);
  text-decoration: none;
}
.ds-card--accent::before {
  content: '';
  position: absolute; top: 0; left: 24px; right: 24px; height: 3px;
  background: var(--color-signal);
  border-radius: 0 0 9999px 9999px;
}
.ds-card__num {
  font-family: var(--font-mono);
  font-size: 13px; font-weight: 700;
  color: var(--color-signal);
  letter-spacing: 0.18em; text-transform: uppercase;
}
.ds-card__icon-wrap {
  width: 56px; height: 56px; border-radius: 16px;
  background: var(--color-signal-soft); color: var(--color-signal);
  display: inline-flex; align-items: center; justify-content: center;
  flex: none;
}
.ds-card__title {
  margin: 0;
  font-size: 24px; font-weight: 700; line-height: 1.2;
  letter-spacing: -0.015em; color: var(--color-ink);
}
.ds-card__lede  {
  margin: 0; color: var(--text-secondary);
  font-size: 16px; line-height: 1.6;
  flex-grow: 1;
}
.ds-card__meta  {
  display: flex; gap: 20px; flex-wrap: wrap;
  font-size: 13px; color: var(--text-muted);
  padding-top: 8px;
  border-top: 1px solid var(--surface-border);
}
.ds-card__meta strong { color: var(--color-ink); font-weight: 600; }
.ds-card__link  {
  display: inline-flex; align-items: center; gap: 8px;
  margin-top: 8px;
  font-weight: 600; font-size: 15px;
  color: var(--color-signal); text-decoration: none;
  transition: gap var(--duration-fast) var(--easing-standard), color var(--duration-fast) var(--easing-standard);
}
a.ds-card:hover .ds-card__link, .ds-card__link:hover {
  color: var(--color-signal-hover);
  gap: 14px;
}
.ds-card--locked { opacity: 0.45; cursor: not-allowed; pointer-events: none; }
.ds-card--locked .badge { background: var(--color-slate-200); color: var(--text-muted); }
.ds-card--inverse {
  background: var(--color-ink); color: var(--color-white);
  border-color: rgba(255, 255, 255, 0.08);
}
.ds-card--inverse .ds-card__title { color: var(--color-white); }
.ds-card--inverse .ds-card__lede  { color: var(--color-slate-300); }
.ds-card--inverse .ds-card__meta  { border-top-color: rgba(255, 255, 255, 0.12); }
.ds-card--inverse .ds-card__meta strong { color: var(--color-white); }

.ds-card-grid {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}
@media (min-width: 1024px) {
  .ds-card-grid { gap: 28px; }
}

/* ── Hero ──────────────────────────────────────────────────────────────── */
.ds-hero {
  position: relative; overflow: hidden;
  padding: 96px 0 88px;
}
.ds-hero--dark {
  background: var(--color-ink); color: var(--color-white);
}
.ds-hero--dark::before {
  content: '';
  position: absolute; inset: 0; pointer-events: none;
  background:
    radial-gradient(60% 80% at 88% 0%, rgba(37, 99, 235, 0.18) 0%, transparent 60%),
    radial-gradient(40% 60% at 0% 100%, rgba(37, 99, 235, 0.10) 0%, transparent 50%);
}
.ds-hero--light {
  background: var(--surface-card);
  border-bottom: 1px solid var(--surface-border);
}
.ds-hero__inner { position: relative; z-index: 1; }
.ds-hero__rule {
  width: 56px; height: 3px; background: var(--color-signal);
  margin: 24px 0 28px; border: none; border-radius: 9999px;
}
.ds-hero h1 {
  font-size: clamp(40px, 6vw, 72px);
  line-height: 1.04;
  letter-spacing: -0.025em;
  font-weight: 800;
  margin: 0 0 24px;
  max-width: 18ch;
}
.ds-hero--dark h1 { color: var(--color-white); }
.ds-hero p.ds-hero__lede {
  font-size: clamp(18px, 1.4vw, 21px);
  line-height: 1.55; max-width: 56ch;
  color: var(--text-secondary);
  margin: 0 0 32px;
}
.ds-hero--dark p.ds-hero__lede { color: var(--color-slate-300); }
.ds-hero__ctas { display: flex; gap: 14px; flex-wrap: wrap; }
.ds-hero__meta {
  display: flex; gap: 32px; flex-wrap: wrap;
  margin-top: 40px; padding-top: 24px;
  border-top: 1px solid rgba(15, 20, 25, 0.08);
  font-size: 14px; color: var(--text-muted);
}
.ds-hero--dark .ds-hero__meta {
  border-top-color: rgba(255, 255, 255, 0.12);
  color: var(--color-slate-300);
}
.ds-hero__meta strong { color: var(--color-ink); font-weight: 600; }
.ds-hero--dark .ds-hero__meta strong { color: var(--color-white); }

@media (max-width: 640px) {
  .ds-hero { padding: 64px 0 56px; }
}

/* ── Section ───────────────────────────────────────────────────────────── */
.ds-section {
  padding: 96px 0;
}
.ds-section--white { background: var(--color-white); border-top: 1px solid var(--surface-border); border-bottom: 1px solid var(--surface-border); }
.ds-section__head {
  margin-bottom: 56px;
}
.ds-section__head h2 {
  font-size: clamp(30px, 3.5vw, 44px);
  line-height: 1.1; letter-spacing: -0.02em;
  font-weight: 700; color: var(--color-ink);
  margin: 0 0 16px;
  max-width: 22ch;
}
.ds-section__head p {
  font-size: 18px; line-height: 1.55;
  color: var(--text-secondary);
  margin: 0;
  max-width: 56ch;
}

@media (max-width: 640px) {
  .ds-section { padding: 64px 0; }
  .ds-section__head { margin-bottom: 40px; }
}

/* ── Stats strip ───────────────────────────────────────────────────────── */
.ds-stats { display: grid; gap: 16px; grid-template-columns: repeat(4, 1fr); margin-bottom: 32px; }
@media (max-width: 720px) { .ds-stats { grid-template-columns: repeat(2, 1fr); } }
.ds-stat {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: 16px;
  padding: 24px;
  text-align: left;
}
.ds-stat__num   {
  font-family: var(--font-mono);
  font-size: 36px; font-weight: 700; line-height: 1;
  color: var(--color-signal); letter-spacing: -0.02em;
}
.ds-stat__label {
  font-size: 11px; color: var(--text-muted);
  margin-top: 12px;
  text-transform: uppercase; letter-spacing: 0.14em;
  font-weight: 600;
}

/* End canonical components */


/* ── Topbar ────────────────────────────────────────────────────────────── */
header.topbar {
  background: rgba(255, 255, 255, 0.7);
  border-bottom: 1px solid var(--surface-border);
  padding: 14px 24px;
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
header.topbar .row {
  max-width: var(--container-learn);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
header.topbar .brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-ink);
  text-decoration: none;
}
header.topbar .brand:hover { text-decoration: none; color: var(--color-ink); }
header.topbar .brand .name {
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  font-size: 16px;
}
header.topbar .brand small {
  color: var(--text-muted);
  font-weight: var(--weight-medium);
  font-size: 13px;
  margin-left: 8px;
}
header.topbar nav a {
  color: var(--text-secondary);
  font-weight: var(--weight-medium);
  font-size: 14px;
  margin-left: 24px;
}
header.topbar nav a.cta {
  background: var(--color-signal);
  color: var(--color-white);
  padding: 8px 16px;
  border-radius: var(--radius-md);
  font-weight: var(--weight-semibold);
  font-size: 13px;
  transition: background var(--duration-fast) var(--easing-standard);
}
header.topbar nav a.cta:hover {
  background: var(--color-signal-hover);
  text-decoration: none;
  color: var(--color-white);
}

/* ── Hero ──────────────────────────────────────────────────────────────── */
section.hero {
  padding: 80px 24px 64px;
  background: var(--surface-card);
  border-bottom: 1px solid var(--surface-border);
}
section.hero.hero-tall { padding: 96px 24px 64px; }
section.hero .row {
  max-width: var(--max-prose);
  margin: 0 auto;
}
.eyebrow {
  font-size: 12px;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  font-weight: var(--weight-semibold);
  color: var(--color-signal);
  margin: 0 0 18px;
}
.eyebrow .pill {
  display: inline-block;
  background: var(--color-signal-soft);
  color: var(--color-signal-strong);
  padding: 5px 12px;
  border-radius: var(--radius-pill);
  margin-right: 12px;
  font-weight: var(--weight-semibold);
}
.signal-rule {
  width: 56px;
  height: 3px;
  background: var(--color-signal);
  margin: 0 0 24px;
  border: none;
  border-radius: var(--radius-pill);
}
h1 {
  margin: 0 0 18px;
  font-size: 44px;
  line-height: 1.08;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-ink);
}
.hero h1.hero-display {
  font-size: 56px;
  line-height: 1.05;
}
@media (max-width: 640px) {
  h1 { font-size: 36px; }
  .hero h1.hero-display { font-size: 38px; }
}
.lede {
  margin: 0 0 28px;
  font-size: 19px;
  color: var(--text-secondary);
  line-height: 1.55;
  max-width: 60ch;
}
.hero-meta {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--text-muted);
  border-top: 1px solid var(--surface-border);
  padding-top: 18px;
  margin-top: 12px;
}
.hero-meta strong { color: var(--color-ink); font-weight: var(--weight-semibold); }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 12px; }

/* Legacy compat: any old `.btn.primary` / `.btn.ghost` markup uses the
   canonical button styles from the BEM block at the top of this file. */
.btn.primary { background: var(--color-signal); color: var(--color-white); box-shadow: var(--shadow-md); }
.btn.primary:hover { background: var(--color-signal-hover); color: var(--color-white); }
.btn.ghost { background: transparent; color: var(--color-signal); border-color: var(--color-signal); }
.btn.ghost:hover { background: var(--color-signal); color: var(--color-white); }

/* ── Body / lesson prose ───────────────────────────────────────────────── */
main {
  max-width: var(--max-prose);
  margin: 0 auto;
  padding: 56px 24px 32px;
}
main h2 {
  font-size: 30px;
  line-height: 1.2;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-ink);
  margin: 48px 0 14px;
}
main h2:first-child { margin-top: 0; }
section#lesson > h2:first-child { margin-top: 0; }
main h3 {
  font-size: 20px;
  font-weight: var(--weight-bold);
  color: var(--color-ink);
  margin: 32px 0 8px;
  letter-spacing: var(--tracking-tight);
}
main p { margin: 0 0 16px; font-size: 17px; color: var(--text-primary); }
/* Restore list bullets that Tailwind Preflight strips. */
main ul { margin: 8px 0 20px; padding-left: 22px; font-size: 17px; list-style: disc; }
main ol { margin: 8px 0 20px; padding-left: 22px; font-size: 17px; list-style: decimal; }
main li { margin-bottom: 6px; }
.callout ul, .archetype-list ul, .review-cta ul { list-style: disc; padding-left: 22px; }
.callout ol { list-style: decimal; padding-left: 22px; }
main strong { color: var(--color-ink); }
main em { color: var(--color-ink); font-style: italic; }

blockquote {
  border-left: 3px solid var(--color-signal);
  margin: 32px 0;
  padding: 8px 0 8px 22px;
  font-size: 20px;
  font-weight: var(--weight-medium);
  color: var(--color-ink);
  font-style: italic;
  line-height: 1.45;
}
blockquote cite {
  display: block;
  font-size: 13px;
  color: var(--text-muted);
  font-style: normal;
  margin-top: 8px;
}

/* Operator-story callout (inverse) */
.story {
  background: var(--surface-inverse);
  color: var(--text-inverse);
  border-radius: var(--radius-lg);
  padding: 32px 36px;
  margin: 36px 0;
}
.story .label {
  font-size: 12px;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  font-weight: var(--weight-semibold);
  color: var(--color-signal-soft);
  margin: 0 0 10px;
}
.story h4 { font-size: 19px; font-weight: var(--weight-bold); color: var(--color-white); margin: 0 0 10px; }
.story p { font-size: 16px; color: var(--color-slate-300); margin: 0 0 8px; line-height: 1.6; }
.story .marker {
  font-family: var(--font-mono);
  font-size: 12px;
  background: rgba(37, 99, 235, 0.18);
  border: 1px dashed rgba(219, 234, 254, 0.35);
  border-radius: var(--radius-sm);
  padding: 5px 10px;
  color: var(--color-signal-soft);
  display: inline-block;
  margin-top: 14px;
  letter-spacing: 0.02em;
}

/* Tactical callout (signal-soft) */
.callout {
  background: var(--color-signal-soft);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  margin: 32px 0;
  font-size: 16px;
}
.callout .label {
  font-size: 12px;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  font-weight: var(--weight-semibold);
  color: var(--color-signal-strong);
  margin: 0 0 10px;
}
.callout h4 { margin: 0 0 10px; font-size: 17px; color: var(--color-ink); font-weight: var(--weight-bold); }
.callout p { color: var(--text-primary); }
.callout p:last-child { margin-bottom: 0; }
.callout ul, .callout ol { margin: 10px 0 0; }

/* Definition grid */
.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 28px 0;
}
@media (max-width: 640px) { .grid { grid-template-columns: 1fr; } }
.grid .cell {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 20px 22px;
  transition: border-color var(--duration-fast) var(--easing-standard),
              transform var(--duration-fast) var(--easing-standard),
              box-shadow var(--duration-base) var(--easing-standard);
}
.grid .cell:hover {
  border-color: var(--color-signal);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}
.grid .cell h4 { margin: 0 0 8px; font-size: 15px; color: var(--color-signal); font-weight: var(--weight-bold); }
.grid .cell p { font-size: 15px; margin: 0; color: var(--text-secondary); }

/* Workbook embed (course landing) */
.workbook {
  background: var(--color-ink);
  color: var(--color-white);
  border-radius: var(--radius-xl);
  padding: 36px;
  margin: 48px 0;
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 28px;
  align-items: center;
}
@media (max-width: 640px) { .workbook { grid-template-columns: 1fr; padding: 28px; } }
.workbook h3 {
  margin: 0 0 10px;
  font-size: 22px;
  font-weight: var(--weight-bold);
  color: var(--color-white);
  letter-spacing: var(--tracking-tight);
}
.workbook p { color: var(--color-slate-300); margin: 0; font-size: 15px; line-height: 1.55; }
.workbook .actions { display: flex; gap: 10px; flex-wrap: wrap; justify-content: flex-end; }
@media (max-width: 640px) { .workbook .actions { justify-content: flex-start; } }
.workbook a.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--color-signal);
  color: var(--color-white);
  padding: 10px 16px;
  border-radius: var(--radius-md);
  font-weight: var(--weight-semibold);
  font-size: 14px;
  text-decoration: none;
  border: 1px solid transparent;
}
.workbook a.btn:hover { background: var(--color-signal-hover); text-decoration: none; color: var(--color-white); }
.workbook a.btn.ghost {
  background: transparent;
  color: var(--color-white);
  border-color: rgba(255, 255, 255, 0.32);
}
.workbook a.btn.ghost:hover { background: rgba(255, 255, 255, 0.08); border-color: var(--color-white); }

/* Diagrams */
.diagram { display: block; margin: 28px auto; max-width: 100%; height: auto; }

/* ── Lesson nav (prev/next cards) ──────────────────────────────────────── */
nav.lesson-nav {
  border-top: 1px solid var(--surface-border);
  margin-top: 56px;
  padding-top: 32px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
@media (max-width: 640px) { nav.lesson-nav { grid-template-columns: 1fr; } }
nav.lesson-nav a {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 18px 22px;
  display: block;
  color: var(--color-ink);
  transition: border-color var(--duration-fast) var(--easing-standard),
              transform var(--duration-base) var(--easing-standard),
              box-shadow var(--duration-base) var(--easing-standard);
}
nav.lesson-nav a:hover {
  border-color: var(--color-signal);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}
nav.lesson-nav small {
  display: block;
  color: var(--color-signal);
  font-size: 12px;
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  font-weight: var(--weight-semibold);
  margin-bottom: 6px;
}
nav.lesson-nav strong { font-size: 16px; font-weight: var(--weight-bold); }
nav.lesson-nav a.next { text-align: right; }

/* ── Course landing (lesson grid) ──────────────────────────────────────── */
.lesson-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 32px 0 12px;
}
@media (max-width: 720px) { .lesson-grid { grid-template-columns: 1fr; } }
.lesson-grid a {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 26px;
  display: block;
  color: var(--color-ink);
  transition: border-color var(--duration-fast) var(--easing-standard),
              transform var(--duration-base) var(--easing-standard),
              box-shadow var(--duration-base) var(--easing-standard);
}
.lesson-grid a:hover {
  border-color: var(--color-signal);
  text-decoration: none;
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.lesson-grid .num {
  font-size: 12px;
  font-weight: var(--weight-semibold);
  color: var(--color-signal);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
}
.lesson-grid h3 { margin: 8px 0 8px; font-size: 19px; font-weight: var(--weight-bold); color: var(--color-ink); }
.lesson-grid p { margin: 0; color: var(--text-secondary); font-size: 14px; line-height: 1.55; }

/* ── Sticky section nav (Lesson · Assignment · Next) ───────────────────── */
nav.section-nav {
  position: sticky;
  /* Sits just below the homepage-style topbar (~64px tall). */
  top: 64px;
  z-index: 40;
  background: rgba(248, 249, 250, 0.92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--surface-border);
  padding: 12px 24px;
}
nav.section-nav .row {
  max-width: var(--max-prose);
  margin: 0 auto;
  display: flex;
  gap: 8px;
}
nav.section-nav a {
  font-size: 13px;
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--color-signal-strong);
  background: var(--color-signal-soft);
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  transition: background var(--duration-fast) var(--easing-standard),
              color var(--duration-fast) var(--easing-standard);
}
nav.section-nav a:hover { text-decoration: none; }
nav.section-nav a[aria-current="true"] {
  background: var(--color-signal);
  color: var(--color-white);
}

/* ── Assignment section ────────────────────────────────────────────────── */
section.assignment {
  border-top: 1px solid var(--surface-border);
  margin-top: 56px;
  padding-top: 48px;
}
section.assignment .heading-row { margin-bottom: 20px; }
section.assignment .heading-row .pill {
  display: inline-block;
  background: var(--color-signal-soft);
  color: var(--color-signal-strong);
  font-size: 12px;
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  margin-bottom: 12px;
}
section.assignment h2 {
  margin: 0 0 6px;
  font-size: 30px;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-ink);
}
section.assignment .save-status,
[data-save-status] {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  margin: 6px 0 24px;
  letter-spacing: 0.02em;
  min-height: 16px;
}
section.assignment p.sub { color: var(--text-secondary); font-size: 16px; margin: 0 0 24px; max-width: 60ch; }

/* Form fields */
.field { margin-bottom: 22px; }
.field label {
  display: block;
  font-weight: var(--weight-semibold);
  margin-bottom: 6px;
  font-size: 14px;
  color: var(--color-ink);
}
.field .hint {
  display: block;
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 10px;
  line-height: 1.45;
}
.field input[type="text"],
.field input[type="email"],
.field textarea {
  width: 100%;
  font-family: inherit;
  font-size: 15px;
  color: var(--color-ink);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 12px 16px;
  background: var(--surface-card);
  transition: border-color var(--duration-fast) var(--easing-standard),
              box-shadow var(--duration-fast) var(--easing-standard);
  resize: vertical;
}
.field input[type="text"]:focus,
.field input[type="email"]:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--color-signal);
  box-shadow: var(--shadow-focus);
}
.field textarea { min-height: 76px; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 640px) { .grid-2 { grid-template-columns: 1fr; } }

.why-stack { display: grid; gap: 12px; }
.why-stack .why-row {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 12px;
  align-items: center;
}
.why-tag {
  background: var(--color-signal-soft);
  color: var(--color-signal-strong);
  font-weight: var(--weight-bold);
  font-size: 13px;
  padding: 10px 0;
  text-align: center;
  border-radius: var(--radius-md);
}
.archetype-list {
  background: var(--color-signal-soft);
  border-radius: var(--radius-lg);
  padding: 22px 24px;
  margin: 0 0 24px;
}
.archetype-list h4 {
  margin: 0 0 10px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
  color: var(--color-signal-strong);
  font-weight: var(--weight-bold);
}
.archetype-list ul { margin: 0; padding-left: 18px; color: var(--color-ink); font-size: 14px; }
.archetype-list li { margin-bottom: 6px; }
.pitch-list { display: grid; gap: 14px; }
.pitch-list .pitch-row {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 12px;
  align-items: start;
}
.pitch-list .pitch-num {
  background: var(--color-ink);
  color: var(--color-white);
  font-weight: var(--weight-bold);
  text-align: center;
  border-radius: var(--radius-pill);
  width: 30px;
  height: 30px;
  line-height: 30px;
  font-size: 13px;
}

.review-cta {
  background: var(--color-signal-soft);
  border-radius: var(--radius-lg);
  padding: 22px 28px;
  margin: 32px 0 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.review-cta p { margin: 0; color: var(--color-signal-strong); font-size: 14px; font-weight: var(--weight-medium); }
.review-cta a {
  background: var(--color-signal);
  color: var(--color-white);
  padding: 10px 18px;
  border-radius: var(--radius-md);
  font-weight: var(--weight-semibold);
  font-size: 14px;
  white-space: nowrap;
}
.review-cta a:hover { background: var(--color-signal-hover); text-decoration: none; color: var(--color-white); }

/* ── Auth-gate overlay ─────────────────────────────────────────────────── */
[data-auth-gate]:not([hidden]) {
  position: fixed;
  inset: 0;
  z-index: var(--z-overlay);
  background: rgba(15, 20, 25, 0.78);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: grid;
  place-items: center;
  padding: 24px;
  animation: ds-auth-fade-in 200ms var(--easing-entrance);
}
@keyframes ds-auth-fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}
[data-auth-gate] .ds-auth-panel {
  background: var(--color-white);
  border-radius: 24px;
  padding: 48px 40px;
  max-width: 480px;
  width: 100%;
  text-align: center;
  box-shadow:
    0 32px 64px -16px rgba(0, 0, 0, 0.5),
    0 0 0 1px rgba(255, 255, 255, 0.08) inset;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}
[data-auth-gate] .ds-auth-panel .badge {
  margin-bottom: 4px;
}
[data-auth-gate] .ds-auth-panel h3 {
  font-size: 28px;
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 700;
  color: var(--color-ink);
  margin: 0;
}
[data-auth-gate] .ds-auth-panel p {
  font-size: 16px;
  line-height: 1.55;
  color: var(--text-secondary);
  margin: 0 0 12px;
  max-width: 36ch;
}
[data-auth-gate] .ds-auth-panel .btn {
  width: 100%;
}
[data-auth-gate] .ds-auth-panel .ds-auth-foot {
  font-size: 13px;
  color: var(--text-muted);
  margin: 8px 0 0;
}
[data-auth-gate] .ds-auth-panel .ds-auth-foot a {
  color: var(--color-signal);
  font-weight: 600;
  text-decoration: none;
}
[data-auth-gate] .ds-auth-panel .ds-auth-foot a:hover {
  text-decoration: underline;
}

/* ── Hub — course-card grid ────────────────────────────────────────────── */
.hub-main { max-width: 1080px; margin: 0 auto; padding: 64px 24px; }
.hub-main section.block { margin-bottom: 72px; }
.hub-main section.block h2 {
  font-size: 36px;
  line-height: 1.2;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-ink);
  margin: 0 0 12px;
}
.hub-main section.block .sub {
  font-size: 17px;
  color: var(--text-secondary);
  margin: 0 0 28px;
  max-width: 60ch;
}

.course-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
@media (max-width: 720px) { .course-grid { grid-template-columns: 1fr; } }
.course-card {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-xl);
  padding: 28px;
  display: block;
  color: var(--color-ink);
  transition: border-color var(--duration-fast) var(--easing-standard),
              transform var(--duration-base) var(--easing-standard),
              box-shadow var(--duration-base) var(--easing-standard);
}
.course-card:hover {
  border-color: var(--color-signal);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
}
.course-card .pill {
  display: inline-block;
  background: var(--color-signal-soft);
  color: var(--color-signal-strong);
  font-size: 11px;
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  margin-bottom: 14px;
}
.course-card h3 {
  margin: 0 0 8px;
  font-size: 22px;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-ink);
}
.course-card p { margin: 0 0 16px; color: var(--text-secondary); font-size: 15px; line-height: 1.55; }
.course-card .meta {
  font-size: 13px;
  color: var(--text-muted);
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.course-card .meta strong { color: var(--color-ink); font-weight: var(--weight-semibold); }
.course-card.locked { opacity: 0.55; cursor: not-allowed; pointer-events: none; }
.course-card.locked .pill { background: var(--color-slate-200); color: var(--text-muted); }

/* ── Login card ────────────────────────────────────────────────────────── */
body.learn-login {
  min-height: 100vh;
  padding: 24px;
  display: grid;
  place-items: center;
}
form[data-login-form] {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 48px 44px;
  max-width: 440px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-slate-200);
}
form[data-login-form] .brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: var(--weight-bold);
  margin-bottom: 32px;
}
form[data-login-form] h1 { font-size: 28px; font-weight: var(--weight-bold); letter-spacing: var(--tracking-tight); margin: 0 0 8px; }
form[data-login-form] p.lede { color: var(--color-slate-700); font-size: 15px; line-height: 1.55; margin: 0 0 28px; }
form[data-login-form] label { display: block; font-weight: var(--weight-semibold); font-size: 13px; margin-bottom: 6px; }
form[data-login-form] input[type="email"],
form[data-login-form] input[type="text"] {
  width: 100%;
  font-family: inherit;
  font-size: 15px;
  padding: 12px 16px;
  border: 1px solid var(--color-slate-200);
  border-radius: var(--radius-md);
}
form[data-login-form] input:focus {
  outline: none;
  border-color: var(--color-signal);
  box-shadow: var(--shadow-focus);
}
form[data-login-form] .actions { display: flex; gap: 10px; margin-top: 16px; flex-wrap: wrap; }
form[data-login-form] button {
  flex: 1;
  min-width: 140px;
  padding: 12px 18px;
  border-radius: var(--radius-md);
  font-family: inherit;
  font-weight: var(--weight-semibold);
  font-size: 14px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background var(--duration-fast) var(--easing-standard),
              border-color var(--duration-fast) var(--easing-standard);
}
form[data-login-form] button.primary { background: var(--color-signal); color: var(--color-white); }
form[data-login-form] button.primary:hover { background: var(--color-signal-hover); }
form[data-login-form] button.ghost { background: var(--color-white); color: var(--color-ink); border-color: var(--color-slate-200); }
form[data-login-form] button.ghost:hover { border-color: var(--color-ink); }
form[data-login-form] .step-2 { margin-top: 28px; padding-top: 24px; border-top: 1px solid var(--color-slate-200); }
form[data-login-form] .footnote { font-size: 12px; color: var(--text-muted); margin-top: 24px; text-align: center; }
form[data-login-form] .footnote a { color: var(--text-secondary); text-decoration: underline; }

/* ── Admin ─────────────────────────────────────────────────────────────── */
header.admin-bar {
  background: var(--color-ink);
  color: var(--color-white);
  padding: 12px 24px;
  border-bottom: 3px solid var(--color-signal);
}
header.admin-bar .row {
  max-width: var(--container-2xl);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
header.admin-bar .badge {
  background: var(--color-signal);
  color: var(--color-white);
  font-size: 11px;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  margin-right: 12px;
}
header.admin-bar .who { font-family: var(--font-mono); font-size: 12px; color: var(--color-slate-300); }

main.admin-main { max-width: var(--container-2xl); margin: 0 auto; padding: 32px 24px; }
.toolbar { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; margin-bottom: 28px; }
.toolbar h1 {
  margin: 0;
  font-size: 30px;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-ink);
  flex: 1;
}
.toolbar input[type="search"] {
  font-family: inherit;
  font-size: 14px;
  padding: 10px 16px;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-md);
  min-width: 240px;
}
.toolbar input[type="search"]:focus {
  outline: none;
  border-color: var(--color-signal);
  box-shadow: var(--shadow-focus);
}
.toolbar a.btn, .toolbar button {
  background: var(--color-signal);
  color: var(--color-white);
  border: none;
  padding: 10px 18px;
  border-radius: var(--radius-md);
  font-family: inherit;
  font-weight: var(--weight-semibold);
  font-size: 14px;
  cursor: pointer;
}
.toolbar a.btn:hover, .toolbar button:hover { background: var(--color-signal-hover); color: var(--color-white); }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-bottom: 32px; }
@media (max-width: 720px) { .stats { grid-template-columns: repeat(2, 1fr); } }
.stat {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.stat .num {
  font-size: 36px;
  font-weight: var(--weight-bold);
  color: var(--color-signal);
  line-height: 1;
  letter-spacing: var(--tracking-tight);
}
.stat .label {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 8px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
  font-weight: var(--weight-semibold);
}

.table-wrap {
  background: var(--surface-card);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}
table.users { width: 100%; border-collapse: collapse; }
table.users th, table.users td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--surface-border);
  font-size: 14px;
}
table.users th {
  background: var(--color-slate-50);
  color: var(--text-muted);
  font-size: 11px;
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
}
table.users tbody tr { cursor: pointer; transition: background var(--duration-instant) var(--easing-standard); }
table.users tbody tr:hover { background: var(--color-slate-50); }
table.users tbody tr.expanded { background: var(--color-signal-soft); }
table.users td.email { font-family: var(--font-mono); font-size: 13px; }
table.users td.progress { font-variant-numeric: tabular-nums; font-weight: var(--weight-semibold); color: var(--color-ink); }
table.users td.muted { color: var(--text-muted); font-size: 13px; }

.detail {
  background: var(--color-signal-soft);
  padding: 24px 28px;
  border-bottom: 1px solid var(--surface-border);
}
.detail h3 {
  font-size: 16px;
  font-weight: var(--weight-bold);
  color: var(--color-signal-strong);
  margin: 0 0 12px;
  text-transform: uppercase;
  letter-spacing: var(--tracking-widest);
}
.detail .lesson-block { margin-bottom: 18px; }
.detail .lesson-block h4 { font-size: 14px; font-weight: var(--weight-bold); color: var(--color-ink); margin: 0 0 8px; }
.detail dl { margin: 0; display: grid; grid-template-columns: 200px 1fr; gap: 6px 18px; }
.detail dt { color: var(--text-muted); font-size: 13px; font-weight: var(--weight-semibold); }
.detail dd {
  margin: 0;
  font-size: 14px;
  color: var(--color-ink);
  white-space: pre-wrap;
  padding-bottom: 6px;
  border-bottom: 1px dashed var(--color-slate-300);
}
.detail dd.empty { color: var(--text-muted); font-style: italic; }

/* ── Footer (inverse) ──────────────────────────────────────────────────── */
footer.site-footer {
  margin-top: 80px;
  padding: 40px 24px;
  background: var(--surface-inverse);
  color: var(--color-slate-300);
  font-size: 14px;
}
footer.site-footer .row {
  max-width: var(--container-learn);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
footer.site-footer .brand-block {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--color-white);
  font-weight: var(--weight-bold);
}
footer.site-footer .brand-block svg { flex: none; }