:root {
  --bg: #0a0e1a;
  --bg-2: #0f1525;
  --bg-3: #161e36;
  --surface: #1a2342;
  --line: #243056;
  --line-2: #2e3c6b;
  --ink: #e8edf7;
  --ink-2: #aab4cf;
  --ink-3: #7a86a8;
  --accent: #22d3ee;
  --accent-2: #06b6d4;
  --accent-glow: rgba(34, 211, 238, 0.15);
  --warn: #fbbf24;
  --ok: #34d399;
  --danger: #f87171;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.5);
  --container: 1200px;
  --font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: -1;
  background:
    radial-gradient(circle at 15% 0%, rgba(34, 211, 238, 0.08), transparent 50%),
    radial-gradient(circle at 85% 100%, rgba(99, 102, 241, 0.06), transparent 50%),
    linear-gradient(180deg, transparent, rgba(0,0,0,0.4));
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: #67e8f9; }
img { max-width: 100%; height: auto; display: block; }
h1, h2, h3, h4 { line-height: 1.2; font-weight: 700; letter-spacing: -0.02em; margin: 0 0 0.5em; }
h1 { font-size: clamp(2rem, 4.5vw, 3.5rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); }
h3 { font-size: 1.25rem; }
p { margin: 0 0 1em; color: var(--ink-2); }
ul, ol { padding-left: 1.2em; color: var(--ink-2); }
li { margin: 0.25em 0; }
code, pre { font-family: var(--font-mono); }

.container { max-width: var(--container); margin: 0 auto; padding: 0 1.5rem; }
.muted { color: var(--ink-3); }
.eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
  position: relative;
  padding-left: 1.5rem;
}
.eyebrow::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 1rem;
  height: 1px;
  background: var(--accent);
}
section { padding: 5rem 0; }
section.compact { padding: 3rem 0; }

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.9rem 1.5rem;
  max-width: var(--container);
  margin: 0 auto;
  gap: 1rem;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
}
.nav-brand img { width: 36px; height: auto; }
.nav-brand span { color: var(--ink-3); font-weight: 400; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  color: var(--ink-2);
  font-size: 0.92rem;
  font-weight: 500;
  padding: 0.55rem 0.85rem;
  border-radius: 8px;
  transition: color 0.15s, background 0.15s;
}
.nav-links a:hover { color: var(--ink); background: var(--bg-3); }
.nav-links a.active { color: var(--accent); }
.nav-cta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--line);
  color: var(--ink);
  width: 40px;
  height: 40px;
  border-radius: 8px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

@media (max-width: 900px) {
  .nav-toggle { display: inline-flex; }
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    background: var(--bg-2);
    border-bottom: 1px solid var(--line);
    padding: 0.5rem;
    gap: 0;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 0.85rem 1rem; border-radius: 8px; }
  .nav-cta { display: none; }
  .nav-cta.in-mobile { display: flex; padding: 0.5rem; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.06s ease, background 0.15s, border 0.15s, box-shadow 0.15s;
  text-decoration: none;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: var(--accent);
  color: #04141a;
  box-shadow: 0 0 0 0 var(--accent-glow);
}
.btn-primary:hover { background: #67e8f9; color: #04141a; box-shadow: 0 0 30px 0 var(--accent-glow); }
.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line-2);
}
.btn-ghost:hover { background: var(--bg-3); color: var(--ink); border-color: var(--accent); }
.btn-link {
  background: transparent;
  color: var(--accent);
  padding: 0.5rem 0;
}
.btn-link:hover { color: #67e8f9; }
.btn-sm { padding: 0.5rem 0.85rem; font-size: 0.85rem; }
.btn-lg { padding: 1rem 1.6rem; font-size: 1.05rem; }
.btn .arrow { transition: transform 0.2s; }
.btn:hover .arrow { transform: translateX(3px); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 6rem 0 5rem;
  overflow: hidden;
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(34, 211, 238, 0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(34, 211, 238, 0.06) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at top, rgba(0,0,0,0.7), transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at top, rgba(0,0,0,0.7), transparent 70%);
  z-index: -1;
}
.hero-inner {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}
.hero h1 .accent {
  background: linear-gradient(120deg, var(--accent), #818cf8 50%, #c084fc);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-lede {
  font-size: clamp(1.05rem, 1.6vw, 1.25rem);
  color: var(--ink-2);
  max-width: 680px;
  margin: 1.25rem auto 2rem;
}
.hero-ctas {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  flex-wrap: wrap;
}
.hero-meta {
  display: flex;
  justify-content: center;
  gap: 2rem;
  margin-top: 3rem;
  flex-wrap: wrap;
  color: var(--ink-3);
  font-size: 0.85rem;
}
.hero-meta strong { color: var(--ink); font-size: 1.4rem; display: block; line-height: 1; margin-bottom: 0.25rem; }

/* ---------- Sections ---------- */
.section-head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 3rem;
}
.section-head p { font-size: 1.05rem; }

/* ---------- Cards / grid ---------- */
.grid {
  display: grid;
  gap: 1.25rem;
}
.grid-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
@media (max-width: 900px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

.card {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: border 0.2s, transform 0.2s;
}
.card:hover { border-color: var(--line-2); transform: translateY(-2px); }
.card h3 { margin-top: 0.5rem; }
.card-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--accent-glow);
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.card-icon svg { width: 22px; height: 22px; }
.card .meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  font-size: 0.8rem;
  color: var(--ink-3);
  margin-bottom: 1rem;
}
.card .meta .tag {
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.15rem 0.6rem;
  color: var(--ink-2);
}

/* ---------- Course outline ---------- */
.module {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  margin-bottom: 1rem;
}
.module summary {
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 600;
  font-size: 1.1rem;
  list-style: none;
  color: var(--ink);
}
.module summary::-webkit-details-marker { display: none; }
.module summary .left { display: flex; align-items: center; gap: 1rem; }
.module .num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  background: var(--accent-glow);
  border-radius: 6px;
  padding: 0.15rem 0.5rem;
}
.module .chev { transition: transform 0.2s; color: var(--ink-3); }
.module[open] .chev { transform: rotate(180deg); }
.module-body { padding-top: 1rem; margin-top: 1rem; border-top: 1px solid var(--line); }
.chapter { padding: 0.75rem 0; }
.chapter h4 { font-size: 0.95rem; color: var(--ink); margin: 0 0 0.25rem; }
.chapter .topics { font-size: 0.88rem; color: var(--ink-3); margin: 0; }
.chapter + .chapter { border-top: 1px dashed var(--line); }

/* ---------- Feature row ---------- */
.feature-row {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 3rem;
  align-items: center;
}
@media (max-width: 900px) { .feature-row { grid-template-columns: 1fr; } }
.feature-row.reverse { direction: rtl; }
.feature-row.reverse > * { direction: ltr; }
.feature-visual {
  background: linear-gradient(135deg, var(--bg-2), var(--bg-3));
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 2rem;
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ---------- Pricing ---------- */
.pricing {
  background: linear-gradient(180deg, var(--bg-2), var(--bg));
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  max-width: 540px;
  margin: 0 auto;
  text-align: center;
}
.pricing .price {
  font-size: 3rem;
  font-weight: 700;
  color: var(--ink);
  line-height: 1;
  margin: 1rem 0 0.25rem;
}
.pricing .price-note { color: var(--ink-3); font-size: 0.9rem; }
.pricing ul {
  list-style: none;
  padding: 0;
  margin: 1.75rem 0;
  text-align: left;
}
.pricing li {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  padding: 0.5rem 0;
  color: var(--ink-2);
}
.pricing li::before {
  content: "";
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
  margin-top: 0.6em;
  flex-shrink: 0;
}

/* ---------- Auth ---------- */
.auth-shell {
  min-height: calc(100vh - 80px);
  display: grid;
  place-items: center;
  padding: 3rem 1.5rem;
}
.auth-card {
  width: 100%;
  max-width: 420px;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
}
.auth-card h1 { font-size: 1.6rem; margin-bottom: 0.25rem; }
.form-row { margin-bottom: 1rem; }
.form-row label {
  display: block;
  font-size: 0.85rem;
  color: var(--ink-2);
  margin-bottom: 0.4rem;
  font-weight: 500;
}
.form-row input {
  width: 100%;
  padding: 0.75rem 0.9rem;
  background: var(--bg);
  border: 1px solid var(--line-2);
  border-radius: 8px;
  color: var(--ink);
  font-size: 0.95rem;
  font-family: inherit;
}
.form-row input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.form-row .row-between {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.form-row a { font-size: 0.85rem; }
.form-note {
  font-size: 0.85rem;
  color: var(--ink-3);
  margin-top: 1.5rem;
  text-align: center;
}
.form-banner {
  background: rgba(251, 191, 36, 0.08);
  border: 1px solid rgba(251, 191, 36, 0.25);
  color: var(--warn);
  padding: 0.75rem 1rem;
  border-radius: 8px;
  font-size: 0.88rem;
  margin-bottom: 1.5rem;
}

/* ---------- Footer ---------- */
.footer {
  margin-top: 4rem;
  border-top: 1px solid var(--line);
  background: var(--bg-2);
  padding: 3rem 0 1.5rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2.5rem;
}
@media (max-width: 900px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .footer-grid { grid-template-columns: 1fr; } }
.footer h4 {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--ink-3);
  margin-bottom: 0.85rem;
}
.footer ul { list-style: none; padding: 0; margin: 0; }
.footer li { margin: 0.4rem 0; }
.footer a { color: var(--ink-2); font-size: 0.92rem; }
.footer a:hover { color: var(--accent); }
.footer .brand-block img { width: 48px; margin-bottom: 0.75rem; }
.footer .brand-block p { font-size: 0.9rem; max-width: 320px; }
.footer-bottom {
  border-top: 1px solid var(--line);
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  color: var(--ink-3);
  font-size: 0.85rem;
}
.footer-socials { display: flex; gap: 0.75rem; }
.footer-socials a {
  width: 36px; height: 36px;
  border: 1px solid var(--line);
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--ink-2);
}
.footer-socials a:hover { border-color: var(--accent); color: var(--accent); }
.footer-socials svg { width: 16px; height: 16px; }

/* ---------- Misc ---------- */
.stack > * + * { margin-top: 1rem; }
.book-cover {
  background: linear-gradient(135deg, #1e2a52, #0a0e1a);
  border: 1px solid var(--line-2);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--ink-3);
}
.book-cover .title {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--ink);
  margin: 1.5rem 0;
  line-height: 1.2;
}
.tag-row { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 1rem 0; }
.tag {
  background: var(--bg-3);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.25rem 0.75rem;
  font-size: 0.8rem;
  color: var(--ink-2);
}

/* ---------- Announce banner ---------- */
.banner {
  background: linear-gradient(90deg, rgba(34, 211, 238, 0.12), rgba(99, 102, 241, 0.12));
  border-bottom: 1px solid var(--line);
  font-size: 0.85rem;
  color: var(--ink-2);
  text-align: center;
  padding: 0.55rem 1rem;
}
.banner strong { color: var(--accent); margin-right: 0.4rem; }
.banner a { font-weight: 600; }

/* ---------- Social proof strip ---------- */
.proof-strip {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem 3rem;
  padding: 1.5rem;
  margin-top: 3rem;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.proof-strip .item { text-align: center; }
.proof-strip strong {
  display: block;
  color: var(--ink);
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1;
}
.proof-strip span {
  display: block;
  font-size: 0.78rem;
  color: var(--ink-3);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-top: 0.4rem;
}

/* ---------- Price hero ---------- */
.price-card {
  background: linear-gradient(180deg, var(--bg-2), var(--bg-3));
  border: 1px solid var(--line-2);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  position: relative;
  overflow: hidden;
}
.price-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), #818cf8);
}
.price-row {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  margin: 1rem 0 0.5rem;
}
.price-row .price {
  font-size: 3.5rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--ink);
  line-height: 1;
}
.price-row .price-old {
  font-size: 1.2rem;
  text-decoration: line-through;
  color: var(--ink-3);
}
.price-row .price-meta { color: var(--ink-3); font-size: 0.95rem; }
.guarantee-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  border: 1px dashed var(--line-2);
  border-radius: 10px;
  margin: 1.5rem 0;
  background: rgba(34, 211, 238, 0.04);
}
.guarantee-row svg {
  width: 28px; height: 28px;
  color: var(--accent);
  flex-shrink: 0;
}
.guarantee-row .copy { font-size: 0.9rem; color: var(--ink-2); }
.guarantee-row .copy strong { color: var(--ink); display: block; }

/* ---------- FAQ ---------- */
.faq {
  max-width: 760px;
  margin: 0 auto;
}
.faq-item {
  border-bottom: 1px solid var(--line);
  padding: 1.25rem 0;
}
.faq-item summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--ink);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--accent);
  font-weight: 400;
  transition: transform 0.2s;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item .answer {
  padding-top: 0.75rem;
  color: var(--ink-2);
  font-size: 0.95rem;
}

/* ---------- Video player shell ---------- */
.video-shell {
  background: #000;
  border-radius: var(--radius-lg);
  overflow: hidden;
  position: relative;
  box-shadow: var(--shadow);
}
.video-shell video {
  display: block;
  width: 100%;
  height: auto;
  background: #000;
}

/* ---------- Testimonials ---------- */
.testimonial {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.75rem;
  position: relative;
}
.testimonial::before {
  content: "“";
  position: absolute;
  top: -0.5rem;
  left: 1rem;
  font-size: 3rem;
  font-family: Georgia, serif;
  color: var(--accent);
  opacity: 0.5;
  line-height: 1;
}
.testimonial blockquote {
  margin: 0 0 1rem;
  font-style: italic;
  color: var(--ink);
  font-size: 1rem;
  line-height: 1.7;
}
.testimonial .who {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.88rem;
}
.testimonial .avatar {
  width: 36px; height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #818cf8);
  color: #04141a;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
}
.testimonial .role { color: var(--ink-3); font-size: 0.8rem; }
.testimonial .stars { color: var(--warn); font-size: 0.9rem; }

/* ---------- Article prose ---------- */
.article-hero {
  padding: 4rem 0 2rem;
}
.article-hero .meta {
  display: flex; gap: 1rem;
  font-size: 0.85rem; color: var(--ink-3);
  margin-bottom: 1rem;
  flex-wrap: wrap;
}
.article-hero .meta .tag { background: var(--bg-3); }
.prose {
  max-width: 720px;
  margin: 0 auto;
  color: var(--ink-2);
  font-size: 1.05rem;
  line-height: 1.8;
}
.prose h2 {
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
  font-size: 1.5rem;
  color: var(--ink);
}
.prose h3 {
  margin-top: 1.75rem;
  margin-bottom: 0.5rem;
  font-size: 1.15rem;
  color: var(--ink);
}
.prose p { margin-bottom: 1.1em; }
.prose ul, .prose ol { padding-left: 1.4em; margin-bottom: 1.2em; }
.prose li { margin: 0.4em 0; }
.prose blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.25rem 0 0.25rem 1.25rem;
  margin: 1.5rem 0;
  color: var(--ink);
  font-style: italic;
}
.prose code {
  background: var(--bg-3);
  border: 1px solid var(--line);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.88em;
}
.prose .callout {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.5rem 0;
  color: var(--ink);
}
.prose .callout strong { color: var(--accent); }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 2.5rem 0; }

/* ---------- Sticky enroll bar (mobile) ---------- */
.sticky-enroll {
  position: sticky;
  bottom: 1rem;
  z-index: 30;
  margin: 2rem 1rem 0;
  background: var(--bg-3);
  border: 1px solid var(--line-2);
  border-radius: 999px;
  padding: 0.5rem 0.5rem 0.5rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  box-shadow: var(--shadow);
  display: none;
}
@media (max-width: 720px) {
  .sticky-enroll { display: flex; }
}

/* ---------- Signature ---------- */
.signature {
  color: var(--ink);
  width: 200px;
  margin-top: 1rem;
}
.signature-name {
  font-size: 0.8rem;
  color: var(--ink-3);
  margin-top: 0.25rem;
}