/* ============================================================
   bitflip — terminal/dev-tool aesthetic, dark-primary
   ============================================================ */

:root {
  /* dark theme (default) */
  --bg-deep:   #07080a;
  --bg:        #0c0e12;
  --surface:   #14171d;
  --surface-2: #1b1f27;
  --border:    #242932;
  --border-strong: #323843;
  --fg:        #dcdfe5;
  --fg-mute:   #9097a3;
  --fg-dim:    #5a606b;
  --accent:    oklch(0.82 0.16 150);   /* terminal green */
  --accent-dim:oklch(0.82 0.16 150 / 0.18);
  --accent-fg: #07080a;
  --warn:      oklch(0.82 0.16 70);
  --pink:      oklch(0.78 0.16 350);
  --blue:      oklch(0.78 0.13 240);
  --shadow:    0 1px 0 rgba(255,255,255,0.03) inset, 0 12px 32px -16px rgba(0,0,0,0.6);
  --radius:    6px;
  --maxw:      1440px;
  --gutter:    clamp(20px, 3vw, 40px);
  --mono:      "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

[data-theme="light"] {
  --bg-deep:   #ececec;
  --bg:        #f4f4f1;
  --surface:   #ffffff;
  --surface-2: #f9f8f4;
  --border:    #e2e1dc;
  --border-strong: #c9c8c2;
  --fg:        #1a1c20;
  --fg-mute:   #5a606b;
  --fg-dim:    #8c919b;
  --accent:    oklch(0.55 0.16 150);
  --accent-dim:oklch(0.55 0.16 150 / 0.14);
  --accent-fg: #ffffff;
  --warn:      oklch(0.62 0.16 70);
  --pink:      oklch(0.55 0.16 350);
  --blue:      oklch(0.50 0.13 240);
  --shadow:    0 1px 0 rgba(0,0,0,0.02) inset, 0 12px 32px -20px rgba(0,0,0,0.18);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--mono);
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
img, svg { display: block; max-width: 100%; }
::selection { background: var(--accent); color: var(--accent-fg); }

/* subtle grid backdrop */
body::before {
  content: "";
  position: fixed; inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: 0.18;
  pointer-events: none;
  mask-image: radial-gradient(ellipse at 50% 0%, #000 0%, transparent 70%);
  z-index: 0;
}

/* ---------- layout primitives ---------- */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gutter); position: relative; z-index: 1; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 2px;
  font-size: 22px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--fg);
  font-weight: 600;
  font-family: var(--mono);
  margin-bottom: 8px;
}
.eyebrow::before {
  content: "$ ";
  color: var(--accent);
  font-weight: 700;
  margin-right: 4px;
  animation: none;
  background: none;
  width: auto; height: auto;
  border-radius: 0;
  box-shadow: none;
  display: inline;
}
.eyebrow::after {
  content: "█";
  color: var(--accent);
  margin-left: 4px;
  animation: blink 1.05s steps(2) infinite;
  font-size: 0.85em;
  line-height: 1;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.85); }
}

.section { padding: 96px 0; position: relative; }
.section + .section { border-top: 1px solid var(--border); }
.section-header { display: flex; flex-direction: column; gap: 14px; margin-bottom: 56px; max-width: 760px; }
.section-header h2 {
  font-size: clamp(28px, 3.4vw, 40px);
  line-height: 1.15;
  margin: 0;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.section-header p {
  color: var(--fg-mute);
  font-size: 16px;
  margin: 0;
  max-width: 64ch;
}

/* ---------- nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 86%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--gutter);
  gap: 32px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 36px;
  margin-left: auto;
  font-family: var(--mono);
}
.nav-item { position: relative; }
.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  border: 0;
  padding: 6px 0;
  font: inherit;
  font-family: var(--mono);
  font-size: 14px;
  font-weight: 500;
  color: var(--fg);
  cursor: pointer;
  letter-spacing: 0;
  position: relative;
  transition: color 0.15s ease;
  text-decoration: none;
}
.nav-link:hover { color: var(--accent); }
.nav-link::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.2s ease;
}
.nav-link:hover::after,
.nav-link[aria-expanded="true"]::after { transform: scaleX(1); }
.nav-caret {
  opacity: 0.7;
  transition: transform 0.15s ease;
}
.nav-link[aria-expanded="true"] .nav-caret {
  transform: rotate(180deg);
  opacity: 1;
}

.nav-cta {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 16px;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  font-size: 13px;
  background: var(--surface);
  font-family: var(--mono);
  transition: border-color 0.15s ease, color 0.15s ease, background 0.15s ease;
}
.nav-cta:hover { border-color: var(--accent); color: var(--accent); }
.nav-cta::before { content: "$"; color: var(--accent); }

@media (max-width: 900px) {
  .nav-links { gap: 22px; }
}
@media (max-width: 720px) {
  .nav-links { display: none; }
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-logo {
  height: 26px;
  width: auto;
  display: block;
}
[data-theme="light"] .brand-logo { filter: invert(1); }
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  font-size: 13px; color: var(--fg-mute);
  transition: color 0.15s ease;
}
.nav-links a:hover { color: var(--fg); }
.nav-cta {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 7px 14px;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  font-size: 13px;
  background: var(--surface);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.nav-cta:hover { border-color: var(--accent); transform: translateY(-1px); }
.nav-cta::before { content: "$"; color: var(--accent); }
@media (max-width: 900px) {
  .nav-links { display: none; }
}

/* ============================================================
   HERO — about bitflip (full-width, centered)
   ============================================================ */
.about-hero {
  text-align: center;
  max-width: 920px;
  margin: 0 auto 64px;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.about-hero .eyebrow { margin-bottom: 22px; }
.about-hero h1 {
  font-size: clamp(36px, 5.4vw, 64px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0 0 22px;
  font-weight: 600;
  white-space: nowrap;
}
.about-hero h1 .static-prefix {
  display: inline;
  color: var(--fg);
  white-space: nowrap;
}
.about-hero h1 .static-prefix::after {
  content: " ›";
  color: var(--accent);
  margin: 0 0.15em;
}
.about-hero h1 .typed-line {
  display: inline;
  white-space: nowrap;
}
.about-hero h1 .accent { display: inline; color: var(--accent); }
.about-hero h1 .caret {
  display: inline-block;
  vertical-align: -2px;
}
@media (max-width: 720px) {
  .about-hero h1 { white-space: normal; font-size: clamp(28px, 7vw, 44px); }
}
.about-hero .lead {
  font-size: 17px;
  line-height: 1.65;
  color: var(--fg-mute);
  max-width: 64ch;
  margin: 0 0 32px;
}
.about-hero .hero-actions { justify-content: center; }

.value-props {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 36px;
  width: 100%;
  margin-top: 8px;
  padding-top: 56px;
  border-top: 1px solid var(--border);
}
@media (max-width: 900px) {
  .value-props { grid-template-columns: 1fr; gap: 24px; padding-top: 36px; }
}
.value-prop {
  display: block;
  text-align: left;
}
.value-prop-body h4 {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  color: var(--fg);
  position: relative;
  padding-left: 16px;
}
.value-prop-body h4::before {
  content: "›";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}
.value-prop-body p {
  margin: 0;
  font-size: 14px;
  color: var(--fg-mute);
  line-height: 1.6;
  padding-left: 16px;
}

/* legacy value-prop overrides removed (defined above) */

/* about card */
.about-card {
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  padding: 22px;
  position: sticky;
  top: 80px;
}
.about-card-label {
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--fg-dim);
  margin-bottom: 18px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
}
.about-card-label::before { content: "// "; color: var(--accent); }
.about-card-list {
  list-style: none; padding: 0; margin: 0 0 18px;
  display: flex; flex-direction: column; gap: 10px;
}
.about-card-list li {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  gap: 12px;
}
.about-card-list .k { color: var(--fg-dim); }
.about-card-list .v { color: var(--fg); text-align: right; white-space: nowrap; }
.about-card-footer {
  display: flex; align-items: center; gap: 8px;
  font-size: 11.5px;
  color: var(--fg-mute);
  padding-top: 14px;
  border-top: 1px solid var(--border);
}
.about-card-dot {
  width: 8px; height: 8px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--accent);
  animation: pulse 2.2s ease-in-out infinite;
}

/* ============================================================
   PYTHON COURSE — coming soon section
   ============================================================ */
.python-course {
  background:
    radial-gradient(ellipse at 50% 0%, color-mix(in srgb, var(--accent) 8%, transparent), transparent 50%),
    var(--bg-deep);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.course-hero {
  text-align: center;
  max-width: 820px;
  margin: 0 auto 64px;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.course-hero-meta {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  font-size: 22px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 28px;
  font-family: var(--mono);
  font-weight: 600;
  color: var(--fg);
}
.course-hero-meta::before {
  content: "$ ";
  color: var(--accent);
  font-weight: 700;
  margin-right: 4px;
}
.course-eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--fg);
  font-weight: 600;
}
.course-eyebrow::after {
  content: "█";
  color: var(--accent);
  margin-left: 6px;
  animation: blink 1.05s steps(2) infinite;
  font-size: 0.85em;
  line-height: 1;
}
.course-eyebrow .dot-soft { display: none; }
.course-eyebrow-sep, .course-eyebrow-faint {
  font-size: 0.7em;
  color: var(--fg-dim);
}
.course-eyebrow .dot-soft {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent);
  animation: pulse 2.2s ease-in-out infinite;
}
.course-eyebrow-sep, .course-eyebrow-faint { color: var(--fg-dim); }

.course-hero h2 {
  margin: 0 0 16px;
  font-size: clamp(32px, 4.4vw, 52px);
  line-height: 1.1;
  font-weight: 600;
  letter-spacing: -0.02em;
}
.course-lead {
  font-size: 16px;
  line-height: 1.65;
  color: var(--fg-mute);
  max-width: 60ch;
  margin: 0 0 32px;
}
.course-lead code {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 8px;
  font-size: 13.5px;
  color: var(--accent);
}

.course-stats {
  display: flex;
  gap: 48px;
  flex-wrap: wrap;
  justify-content: center;
  margin: 8px 0 32px;
}
.course-stats > div {
  display: flex; flex-direction: column;
  text-align: center;
  gap: 4px;
}
.course-stats .stat-num {
  font-size: 32px;
  font-weight: 600;
  color: var(--fg);
  line-height: 1;
}
.course-stats .stat-label {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg-dim);
}

.course-progress {
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.course-progress-bar {
  position: relative;
  height: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
}
.course-progress-fill {
  position: absolute;
  inset: 0;
  width: 78%;
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--accent) 60%, transparent),
    var(--accent));
  border-radius: 999px;
  animation: countdownGlow 2.4s ease-in-out infinite;
}
.course-progress-fill::after {
  content: "";
  position: absolute;
  right: -2px; top: 50%;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--accent);
  transform: translateY(-50%);
  box-shadow: 0 0 14px var(--accent);
}
.course-progress-label {
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-mute);
  text-align: center;
}
.course-progress-label::before { content: "› "; color: var(--accent); }

/* final project panel */
.final-project {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 48px;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}
@media (max-width: 980px) {
  .final-project { grid-template-columns: 1fr; gap: 32px; }
}
.final-project-meta { max-width: 44ch; }
.final-project-tag {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-dim);
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 16px;
}
.final-project-meta h3 {
  margin: 0 0 14px;
  font-size: clamp(24px, 2.6vw, 32px);
  white-space: nowrap;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.2;
}
.final-project-meta p {
  margin: 0 0 20px;
  color: var(--fg-mute);
  font-size: 15px;
  line-height: 1.6;
}
.final-project-checklist {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.final-project-checklist li {
  font-size: 13.5px;
  color: var(--fg);
  display: flex;
  align-items: center;
  gap: 10px;
}
.final-project-checklist li::before {
  content: "✓";
  color: var(--accent);
  font-weight: 700;
}
.course-dot.soon-dot {
  background: var(--warn);
  box-shadow: 0 0 8px var(--warn);
  animation: pulse 2.2s ease-in-out infinite;
}
.course-meta.soon {
  background: color-mix(in srgb, var(--warn) 22%, transparent);
  color: var(--warn);
}

/* countdown / status bar in hero */
.countdown {
  margin: 14px 0 28px;
  max-width: 460px;
}
.countdown-bar {
  position: relative;
  height: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
}
.countdown-fill {
  position: absolute;
  inset: 0;
  width: 78%;
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--accent) 60%, transparent),
    var(--accent));
  border-radius: 999px;
  animation: countdownGlow 2.4s ease-in-out infinite;
}
.countdown-fill::after {
  content: "";
  position: absolute;
  right: -2px; top: 50%;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--accent);
  transform: translateY(-50%);
  box-shadow: 0 0 14px var(--accent);
}
.countdown-label {
  position: absolute;
  top: 14px; left: 0;
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-mute);
}
.countdown-label::before {
  content: "› ";
  color: var(--accent);
}
@keyframes countdownGlow {
  0%, 100% { opacity: 0.85; }
  50% { opacity: 1; }
}

/* instructor section — full-width two-column layout */
.instructor-section .wrap { max-width: var(--maxw); }
.instructor-layout {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 80px;
  align-items: start;
}
@media (max-width: 980px) {
  .instructor-layout { grid-template-columns: 1fr; gap: 32px; }
}
.instructor-heading { position: sticky; top: 96px; }
.instructor-heading .eyebrow { margin-bottom: 22px; }
.instructor-heading h2 {
  margin: 0 0 16px;
  font-size: clamp(28px, 3.4vw, 44px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  font-weight: 600;
  /* allow the long sentence to flow naturally on wide screens; restrict only if very narrow */
}
.instructor-sub {
  margin: 0;
  color: var(--fg-mute);
  font-size: 15px;
  line-height: 1.55;
  max-width: 44ch;
}
.instructor-info h3 {
  margin: 0 0 8px;
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.instructor-info .role { color: var(--accent); font-size: 13px; margin-bottom: 20px; }
.instructor-info p { margin: 0 0 14px; color: var(--fg-mute); font-size: 14px; line-height: 1.7; }
.instructor-info .instructor-tags {
  list-style: none; padding: 0; margin: 22px 0 0;
  display: flex; flex-wrap: wrap; gap: 6px;
}
.instructor-info .instructor-tags li {
  font-size: 11.5px;
  padding: 4px 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--fg-mute);
  white-space: nowrap;
}
.courses-menu {
  position: absolute;
  top: calc(100% + 14px);
  left: -16px;
  min-width: 340px;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  padding: 8px;
  font-family: var(--mono);
  box-shadow:
    0 1px 0 rgba(255,255,255,0.03) inset,
    0 20px 48px -12px rgba(0,0,0,0.55);
  z-index: 60;
  opacity: 0;
  transform: translateY(-4px);
  pointer-events: none;
  transition: opacity 0.15s ease, transform 0.15s ease;
}
.courses-menu.open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.courses-menu-label {
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--fg-dim);
  padding: 8px 10px 10px;
}
.course-row {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 10px 12px;
  background: transparent;
  border: 0;
  border-radius: 5px;
  font-family: inherit;
  text-align: left;
  cursor: pointer;
  color: var(--fg);
  transition: background 0.15s;
}
.course-row:hover {
  background: var(--surface-2);
}
.course-row.active {
  background: var(--accent-dim);
}
.course-row.active .course-name {
  color: var(--accent);
}
.course-row-text {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}
.course-row .course-name {
  font-size: 13.5px;
  font-weight: 500;
}
.course-row .course-desc {
  font-size: 11.5px;
  color: var(--fg-mute);
}
.course-row .course-meta {
  font-size: 10px;
  padding: 3px 7px;
  border-radius: 3px;
  background: var(--surface-2);
  color: var(--fg-dim);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  flex-shrink: 0;
}
.course-row.active .course-meta {
  background: var(--accent);
  color: var(--accent-fg);
}
.course-row .course-dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent);
  flex-shrink: 0;
}
/* legacy sidebar styles removed — courses now live in top nav */

/* ---------- hero ---------- */
.hero {
  padding: 80px 0 88px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; inset: -10% -10% auto -10%; height: 320px;
  background: radial-gradient(ellipse at 30% 0%, var(--accent-dim), transparent 60%);
  pointer-events: none;
  filter: blur(10px);
  z-index: 0;
}
.hero .wrap { position: relative; z-index: 1; }

/* ---------- bit-feature (contained 3D viz, paired with text) ---------- */
.bit-feature {
  padding: 88px 0;
  border-top: 1px solid var(--border);
}
.bit-feature-grid {
  display: grid;
  grid-template-columns: 1fr 1.15fr;
  gap: 64px;
  align-items: center;
}
@media (max-width: 880px) {
  .bit-feature-grid { grid-template-columns: 1fr; gap: 36px; }
}
.bit-feature-text { max-width: 44ch; }
.bit-feature-text h2 {
  font-size: clamp(26px, 3vw, 36px);
  line-height: 1.15;
  white-space: nowrap;
  letter-spacing: -0.01em;
  font-weight: 600;
  margin: 14px 0 16px;
}
.bit-feature-text p {
  color: var(--fg-mute);
  font-size: 15px;
  line-height: 1.65;
  margin: 0 0 12px;
}
.bit-feature-sub {
  font-size: 12px !important;
  color: var(--fg-dim) !important;
  margin-top: 14px !important;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.bit-feature-sub::before {
  content: "◤";
  color: var(--accent);
}

.bit-feature-frame {
  position: relative;
  height: 460px;
  overflow: visible;
}
.bit-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; gap: 48px; }
}
.hero-left .eyebrow { margin-bottom: 22px; }
.hero h1 {
  font-size: clamp(32px, 4.4vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin: 0 0 22px;
  font-weight: 600;
}
.hero-left { min-width: 0; }
.hero h1 .typed-line {
  display: inline;
}
.hero h1 .accent { display: inline; color: var(--accent); }
.hero h1 .caret {
  display: inline-block;
  width: 0.55ch;
  background: var(--accent);
  margin-left: 4px;
  vertical-align: -3px;
  height: 0.9em;
  animation: blink 1.05s steps(2) infinite;
}
@keyframes blink { 50% { opacity: 0; } }
.hero p.lead {
  font-size: 17px;
  line-height: 1.55;
  color: var(--fg-mute);
  margin: 0 0 32px;
  max-width: 52ch;
}
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 12px 18px;
  border-radius: 5px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  cursor: pointer;
  transition: transform 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}
.btn:hover { transform: translateY(-1px); border-color: var(--accent); }
.btn-primary {
  background: var(--accent);
  color: var(--accent-fg);
  border-color: var(--accent);
}
.btn-primary:hover { background: color-mix(in srgb, var(--accent) 86%, white); }
.btn::before { content: ">"; color: var(--accent); font-weight: 700; }
.btn-primary::before { color: var(--accent-fg); }

.hero-meta {
  margin-top: 36px;
  display: flex; gap: 36px;
  color: var(--fg-mute);
  font-size: 13px;
  flex-wrap: wrap;
}
.hero-meta .stat-num { color: var(--fg); font-size: 22px; display: block; font-weight: 600; }

/* ---------- terminal / chat window ---------- */
.window {
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.window-bar {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 14px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  color: var(--fg-mute);
}
.window-dots { display: flex; gap: 6px; }
.window-dots span {
  width: 11px; height: 11px; border-radius: 50%;
  background: var(--border-strong);
}
.window-dots span:nth-child(1) { background: #ed6a5e; }
.window-dots span:nth-child(2) { background: #f6c155; }
.window-dots span:nth-child(3) { background: #62c554; }
.window-title { margin-left: auto; font-family: var(--mono); }

.chat-body {
  padding: 18px;
  min-height: 360px;
  max-height: 480px;
  overflow-y: auto;
  display: flex; flex-direction: column; gap: 14px;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}
.chat-body::-webkit-scrollbar { width: 8px; }
.chat-body::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 4px; }
.chat-msg { font-size: 13.5px; line-height: 1.6; }
.chat-msg .who {
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-dim);
  margin-bottom: 4px;
}
.chat-msg .bubble {
  white-space: pre-wrap;
  color: var(--fg);
}
.chat-msg.user .who { color: var(--accent); }
.chat-msg.user .who::before { content: ">_ "; }
.chat-msg.bot .bubble { color: var(--fg); }
.chat-msg.bot .bubble code,
.chat-msg.bot .bubble pre {
  background: var(--bg-deep);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 12.5px;
}
.chat-msg.bot .bubble pre {
  padding: 10px 12px;
  margin: 8px 0 0;
  overflow-x: auto;
}
.chat-msg .typing {
  display: inline-block;
  width: 8px; height: 14px;
  background: var(--accent);
  vertical-align: -2px;
  animation: blink 0.9s steps(2) infinite;
}

.chat-input {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  border-top: 1px solid var(--border);
  background: var(--surface-2);
}
.chat-input::before {
  content: "$";
  color: var(--accent);
  font-weight: 700;
}
.chat-input input {
  flex: 1;
  background: transparent;
  border: 0;
  outline: 0;
  font: inherit;
  color: var(--fg);
  padding: 6px 0;
}
.chat-input input::placeholder { color: var(--fg-dim); }
.chat-input button {
  background: transparent;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 6px 12px;
  font-size: 12px;
  cursor: pointer;
  color: var(--fg-mute);
  transition: all 0.15s ease;
}
.chat-input button:hover:not(:disabled) { color: var(--accent); border-color: var(--accent); }
.chat-input button:disabled { opacity: 0.4; cursor: not-allowed; }

.chat-suggestions {
  display: flex; flex-wrap: wrap; gap: 6px;
  padding: 8px 16px 14px;
  border-top: 1px solid var(--border);
  background: var(--surface-2);
}
.chat-suggestions button {
  font-size: 12px;
  color: var(--fg-mute);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 10px;
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}
.chat-suggestions button:hover { color: var(--accent); border-color: var(--accent); }

/* ---------- modules / curriculum ---------- */
.modules {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}
@media (max-width: 800px) { .modules { grid-template-columns: 1fr; } }

.module {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 26px;
  display: flex; flex-direction: column; gap: 14px;
  position: relative;
  transition: border-color 0.2s ease, transform 0.2s ease, background 0.2s ease;
  opacity: 0;
  transform: translateY(20px);
}
.module.in-view { opacity: 1; transform: translateY(0); transition-delay: var(--delay, 0ms); }
.module:hover { border-color: var(--accent); transform: translateY(-2px); }
.module.coming { opacity: 0.78; }
.module.coming:hover { border-color: var(--border-strong); }

.module-head {
  display: flex; align-items: baseline; justify-content: space-between; gap: 12px;
}
.module-num {
  font-size: 11px; letter-spacing: 0.12em;
  color: var(--fg-dim);
  text-transform: uppercase;
}
.module-status {
  font-size: 10.5px;
  padding: 3px 8px;
  border-radius: 999px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.module-status.live { background: var(--accent-dim); color: var(--accent); }
.module-status.soon { background: var(--surface-2); color: var(--fg-dim); border: 1px solid var(--border); }
.module h3 {
  margin: 0;
  font-size: 22px;
  letter-spacing: -0.01em;
  font-weight: 600;
}
.module h3 .block-label {
  display: block;
  font-size: 12.5px;
  font-weight: 400;
  color: var(--accent);
  margin-top: 4px;
  letter-spacing: 0;
}
.module p { margin: 0; color: var(--fg-mute); font-size: 13.5px; line-height: 1.6; }
.module-topics {
  list-style: none; padding: 0; margin: 0;
  display: flex; flex-wrap: wrap; gap: 6px;
}
.module-topics li {
  font-size: 11.5px;
  padding: 3px 8px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--fg-mute);
}
.module-link {
  margin-top: auto;
  padding-top: 14px;
  font-size: 12.5px;
  color: var(--accent);
  display: inline-flex; align-items: center; gap: 6px;
  border-top: 1px solid var(--border);
}
.module-link span { transition: transform 0.15s ease; }
.module:hover .module-link span { transform: translateX(3px); }

/* visual bot-building diagram on right of curriculum intro */
.curriculum-intro {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: 48px;
  align-items: start;
  margin-bottom: 56px;
}
@media (max-width: 900px) { .curriculum-intro { grid-template-columns: 1fr; } }

.bot-diagram {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  font-size: 12.5px;
}
.bot-diagram-title {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg-dim);
  margin-bottom: 14px;
}
.bot-blocks { display: flex; flex-direction: column; gap: 6px; }
.bot-block {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--surface-2);
  position: relative;
  transition: border-color 0.2s ease, background 0.2s ease;
}
.bot-block .idx {
  width: 22px; height: 22px;
  display: grid; place-items: center;
  font-size: 11px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--fg-mute);
}
.bot-block .label { flex: 1; color: var(--fg); }
.bot-block .desc { color: var(--fg-dim); font-size: 11.5px; }
.bot-block.active { border-color: var(--accent); }
.bot-block.active .idx { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
.bot-block.active .label { color: var(--accent); }

/* ---------- outcomes ---------- */
.outcomes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
@media (max-width: 880px) { .outcomes { grid-template-columns: 1fr; } }
.outcome {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 26px;
  display: flex; flex-direction: column; gap: 10px;
  opacity: 0; transform: translateY(20px);
}
.outcome.in-view { opacity: 1; transform: translateY(0); transition: opacity 0.6s ease var(--delay,0ms), transform 0.6s ease var(--delay,0ms); }
.outcome .icon {
  font-size: 18px; color: var(--accent);
  margin-bottom: 4px;
}
.outcome h4 { margin: 0; font-size: 15px; font-weight: 600; }
.outcome p { margin: 0; color: var(--fg-mute); font-size: 13px; line-height: 1.55; }

/* ---------- instructor ---------- */
.instructor {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 48px;
  align-items: center;
}
@media (max-width: 800px) { .instructor { grid-template-columns: 1fr; gap: 32px; } }

.instructor-photo {
  width: 100%;
  aspect-ratio: 1;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background:
    repeating-linear-gradient(
      45deg,
      var(--surface) 0 12px,
      var(--surface-2) 12px 24px
    );
  position: relative;
  display: grid; place-items: center;
  overflow: hidden;
}
.instructor-photo::before {
  content: "[ instructor photo ]";
  position: absolute;
  bottom: 12px; left: 12px;
  font-size: 10.5px;
  color: var(--fg-dim);
  background: var(--bg);
  padding: 3px 8px;
  border-radius: 4px;
  border: 1px solid var(--border);
}
.instructor-photo::after {
  content: "▢";
  font-size: 48px;
  color: var(--fg-dim);
  opacity: 0.5;
}
.instructor-info h3 {
  margin: 0 0 8px;
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.instructor-info .role { color: var(--accent); font-size: 13px; margin-bottom: 18px; }
.instructor-info p { margin: 0 0 12px; color: var(--fg-mute); font-size: 14px; line-height: 1.65; }
.instructor-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 16px; }
.instructor-tags li {
  list-style: none;
  font-size: 11.5px;
  padding: 4px 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--fg-mute);
}

/* ---------- cta ---------- */
.cta {
  background:
    radial-gradient(ellipse at 80% 50%, var(--accent-dim), transparent 60%),
    var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: clamp(40px, 6vw, 64px);
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 36px;
  align-items: center;
}
@media (max-width: 800px) { .cta { grid-template-columns: 1fr; } }
.cta h3 {
  margin: 0 0 12px;
  font-size: clamp(24px, 3vw, 34px);
  font-weight: 600;
  letter-spacing: -0.01em;
}
.cta p { margin: 0; color: var(--fg-mute); max-width: 50ch; }
.cta-form { display: flex; gap: 8px; align-items: center; }
.cta-form input {
  background: var(--bg);
  border: 1px solid var(--border-strong);
  border-radius: 5px;
  padding: 12px 14px;
  color: var(--fg);
  font: inherit;
  font-size: 13.5px;
  min-width: 240px;
  outline: none;
  transition: border-color 0.15s ease;
}
.cta-form input:focus { border-color: var(--accent); }

/* ---------- footer ---------- */
.footer {
  border-top: 1px solid var(--border);
  padding: 36px 0;
  margin-top: 32px;
  color: var(--fg-dim);
  font-size: 12.5px;
}
.footer-inner {
  display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap;
  align-items: center;
}
.footer a:hover { color: var(--accent); }
.footer-links { display: flex; gap: 24px; }

/* ---------- tweaks panel ---------- */
.tweaks-toggle {
  position: fixed;
  bottom: 18px; right: 18px;
  z-index: 60;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  padding: 8px 14px;
  display: flex; align-items: center; gap: 8px;
  cursor: pointer;
  font-size: 12px;
  color: var(--fg-mute);
  box-shadow: var(--shadow);
  display: none;
}
.tweaks-toggle.show { display: inline-flex; }
.tweaks-toggle:hover { color: var(--accent); border-color: var(--accent); }
.tweaks-toggle .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); }

.tweaks-panel {
  position: fixed;
  bottom: 60px;
  right: 18px;
  z-index: 61;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  width: 260px;
  padding: 16px;
  box-shadow: 0 24px 56px -16px rgba(0,0,0,0.5);
  display: none;
  flex-direction: column; gap: 14px;
}
.tweaks-panel.open { display: flex; }
.tweaks-head {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-dim);
}
.tweaks-head button {
  background: transparent;
  border: 0;
  color: var(--fg-mute);
  font-size: 14px;
  cursor: pointer;
}
.tweaks-row { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.tweaks-row .label { font-size: 13px; color: var(--fg); }
.theme-segments {
  display: flex;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px;
}
.theme-segments button {
  background: transparent;
  border: 0;
  padding: 6px 14px;
  font-size: 12px;
  color: var(--fg-mute);
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.15s ease;
}
.theme-segments button.active {
  background: var(--accent);
  color: var(--accent-fg);
}

/* viz segments mirror the theme-segments style */
.viz-segments {
  display: flex;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px;
}
.viz-segments button {
  background: transparent;
  border: 0;
  padding: 6px 12px;
  font-size: 11.5px;
  color: var(--fg-mute);
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.15s ease;
}
.viz-segments button.active {
  background: var(--accent);
  color: var(--accent-fg);
}

/* ---------- reveal on scroll ---------- */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.in-view { opacity: 1; transform: translateY(0); }
.module { transition: opacity 0.6s ease, transform 0.6s ease, border-color 0.2s ease, background 0.2s ease; }