/*
 * motion.css — the animation & interaction layer
 *
 * This file bolts onto the existing styles and elevates the course with:
 *   · ambient motion  (grid parallax, scanline, noise, cursor glow)
 *   · scroll reveals  (.reveal, .reveal-stagger)
 *   · signal micro-FX (number roll-up, pill burst, success ripple)
 *   · richer hover states (3D card tilt, magnet, scanline wipe, border flow)
 *   · hero theater     (typing, draw-in arrows, particle flow in the loop diagram)
 *   · widget polish   (quiz correct/wrong FX, diff line stagger, flashcard physics)
 *
 * All animations respect `prefers-reduced-motion: reduce`.
 */

/* ============================================================
 * 01 — KEYFRAMES
 * ============================================================ */

@keyframes m-rise {
  0%   { opacity: 0; transform: translate3d(0, 14px, 0); filter: blur(6px); }
  60%  { filter: blur(0); }
  100% { opacity: 1; transform: translate3d(0, 0, 0); filter: blur(0); }
}
@keyframes m-fade {
  from { opacity: 0; }
  to   { opacity: 1; }
}
@keyframes m-rise-left {
  from { opacity: 0; transform: translate3d(-18px, 0, 0); }
  to   { opacity: 1; transform: translate3d(0, 0, 0); }
}
@keyframes m-scale-in {
  from { opacity: 0; transform: scale(.94); }
  to   { opacity: 1; transform: scale(1); }
}
@keyframes m-pop {
  0%   { transform: scale(.6); opacity: 0; }
  60%  { transform: scale(1.08); opacity: 1; }
  100% { transform: scale(1); opacity: 1; }
}
@keyframes m-shake {
  10%, 90% { transform: translate3d(-1px, 0, 0); }
  20%, 80% { transform: translate3d(2px, 0, 0); }
  30%, 50%, 70% { transform: translate3d(-3px, 0, 0); }
  40%, 60% { transform: translate3d(3px, 0, 0); }
}
@keyframes m-flow-dash {
  to { stroke-dashoffset: -48; }
}
@keyframes m-particle {
  0%   { offset-distance: 0%;   opacity: 0; }
  15%  { opacity: 1; }
  85%  { opacity: 1; }
  100% { offset-distance: 100%; opacity: 0; }
}
@keyframes m-scan {
  from { transform: translate3d(-100%, 0, 0); }
  to   { transform: translate3d(200%, 0, 0); }
}
@keyframes m-burst {
  0%   { transform: translateY(0) scale(1); opacity: 1; }
  100% { transform: translateY(-34px) scale(1.05); opacity: 0; }
}
@keyframes m-cursor {
  50% { opacity: 0; }
}
@keyframes m-stripe {
  from { background-position: 0 0; }
  to   { background-position: 28px 0; }
}
@keyframes m-grid-drift {
  from { transform: translate3d(0, 0, 0); }
  to   { transform: translate3d(-48px, -48px, 0); }
}
@keyframes m-glow-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(57, 170, 235, 0); }
  50%      { box-shadow: 0 0 0 6px rgba(57, 170, 235, .18); }
}
@keyframes m-typing-caret {
  50% { background: transparent; }
}
@keyframes m-rail-travel {
  from { transform: scaleY(0); }
  to   { transform: scaleY(1); }
}
@keyframes m-boot {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes m-progress-indeterminate {
  0%   { background-position: 0% 50%; }
  100% { background-position: 200% 50%; }
}

/* ============================================================
 * 02 — SCROLL REVEAL
 *   Add .reveal (or .reveal-left / .reveal-scale) to any element.
 *   JS adds .in when the element enters the viewport.
 * ============================================================ */

.reveal,
.reveal-left,
.reveal-scale { opacity: 0; will-change: transform, opacity, filter; }

.reveal.in        { animation: m-rise       .7s cubic-bezier(.2,.7,.2,1) both; }
.reveal-left.in   { animation: m-rise-left  .65s cubic-bezier(.2,.7,.2,1) both; }
.reveal-scale.in  { animation: m-scale-in   .6s cubic-bezier(.2,.7,.2,1) both; }

/* Stagger utility: JS adds .in to the parent; children animate in sequence */
.reveal-stagger > * { opacity: 0; }
.reveal-stagger.in > *:nth-child(1)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1)  40ms both; }
.reveal-stagger.in > *:nth-child(2)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 100ms both; }
.reveal-stagger.in > *:nth-child(3)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 160ms both; }
.reveal-stagger.in > *:nth-child(4)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 220ms both; }
.reveal-stagger.in > *:nth-child(5)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 280ms both; }
.reveal-stagger.in > *:nth-child(6)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 340ms both; }
.reveal-stagger.in > *:nth-child(7)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 400ms both; }
.reveal-stagger.in > *:nth-child(8)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 460ms both; }
.reveal-stagger.in > *:nth-child(9)  { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 520ms both; }
.reveal-stagger.in > *:nth-child(n+10) { animation: m-rise .55s cubic-bezier(.2,.7,.2,1) 580ms both; }

/* ============================================================
 * 03 — HERO: typing headline, ambient grid, aurora scrim
 * ============================================================ */

.hero { isolation: isolate; }

/* Grid that slowly drifts — gives the sense of "floating in a terminal". */
.hero .hero-grid-bg {
  animation: m-grid-drift 48s linear infinite;
  will-change: transform;
}

/* Aurora — a soft cyan bloom low-right that breathes.  */
.hero::before {
  content: '';
  position: absolute; z-index: 0;
  right: -8%; bottom: -12%;
  width: 48rem; height: 48rem;
  pointer-events: none;
  background:
    radial-gradient(circle at 50% 50%,
      color-mix(in oklch, var(--cyan) 40%, transparent) 0%,
      transparent 55%);
  filter: blur(40px);
  opacity: 0.55;
  animation: m-glow-pulse 6s ease-in-out infinite;
}

/* Scanline — soft, slow travel */
.hero .hero-scanline {
  animation: m-grid-drift 24s linear infinite;
  animation-direction: reverse;
}

/* Title: l1 types in, l2 slides + em-word highlight swipe */
.hero-title .l1,
.hero-title .l2 { overflow: hidden; }
.hero-title .l1 {
  /* "An agent in" — a clean rise & settle */
  animation: m-rise .75s cubic-bezier(.2,.7,.2,1) .12s both;
}
.hero-title .l2 {
  animation: m-rise .85s cubic-bezier(.2,.7,.2,1) .34s both;
}
.hero-title .l2 em {
  position: relative;
  background: linear-gradient(180deg, transparent 55%, color-mix(in oklch, var(--cyan) 45%, transparent) 55%);
  background-size: 0% 100%;
  background-repeat: no-repeat;
  animation: m-hl-sweep 1.1s cubic-bezier(.2,.7,.2,1) .9s forwards;
}
@keyframes m-hl-sweep {
  to { background-size: 100% 100%; }
}

.hero-rail { animation: m-fade .6s ease both; }
.hero-lede { animation: m-rise .7s cubic-bezier(.2,.7,.2,1) .55s both; }
.hero-cta  { animation: m-rise .7s cubic-bezier(.2,.7,.2,1) .7s  both; }
.hero-meta { animation: m-rise .7s cubic-bezier(.2,.7,.2,1) .85s both; }

/* cursor caret in the hero title */
.hero-title .blink-caret { animation: m-cursor .85s step-end infinite; }

/* hero-diagram — comes in last, slides up with a glow */
.hero-diagram {
  animation: m-rise 1s cubic-bezier(.2,.7,.2,1) 1s both;
}
.hero-diagram .hd-col .label::before {
  animation: m-glow-pulse 2.2s ease-in-out infinite;
}

/* The inline code minis in the hero diagram — subtle blink on the caret */
.hero-diagram .hd-col .mini::after {
  content: '▍';
  color: var(--cyan);
  margin-left: 2px;
  animation: m-cursor 1s step-end infinite;
}

/* ============================================================
 * 04 — STATS BAND: count-up numbers
 * ============================================================ */

.stats-bar .stat            { position: relative; overflow: hidden; }
.stats-bar .stat::before {
  /* an accent stripe on hover */
  content: ''; position: absolute;
  left: 0; right: 0; top: 0; height: 2px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  transform: translateX(-100%);
  transition: transform .6s cubic-bezier(.2,.7,.2,1);
}
.stats-bar .stat:hover::before { transform: translateX(100%); }
.stats-bar .stat .n         { display: inline-block; }

/* ============================================================
 * 05 — LESSON CARDS: magnetic hover, corner marks, 3D tilt
 * ============================================================ */

.lesson-card {
  transform: perspective(900px) rotateX(0) rotateY(0);
  transition: transform .35s cubic-bezier(.2,.7,.2,1),
              box-shadow .35s cubic-bezier(.2,.7,.2,1),
              border-color .25s;
  will-change: transform;
}
.lesson-card::before {
  /* corner tick — top-right */
  content: '';
  position: absolute;
  top: 10px; right: 10px;
  width: 10px; height: 10px;
  border-top: 1px solid var(--ink-4);
  border-right: 1px solid var(--ink-4);
  opacity: .55;
  transition: all .3s cubic-bezier(.2,.7,.2,1);
}
.lesson-card:hover::before {
  border-color: var(--cyan-ink);
  width: 16px; height: 16px;
  opacity: 1;
}

/* sweeping scanline on hover */
.lesson-card .sweep {
  position: absolute; inset: 0;
  pointer-events: none;
  overflow: hidden;
  border-radius: inherit;
}
.lesson-card .sweep::after {
  content: '';
  position: absolute;
  top: 0; bottom: 0; left: 0;
  width: 40%;
  background: linear-gradient(90deg,
    transparent 0%,
    color-mix(in oklch, var(--cyan) 16%, transparent) 50%,
    transparent 100%);
  transform: translate3d(-120%, 0, 0) skewX(-12deg);
  transition: transform .7s cubic-bezier(.2,.7,.2,1);
}
.lesson-card:hover .sweep::after { transform: translate3d(380%, 0, 0) skewX(-12deg); }

.lesson-card .arrow {
  transition: transform .3s cubic-bezier(.2,.7,.2,1);
}
.lesson-card:hover .arrow { transform: translate3d(6px, 0, 0); }

.lesson-card .num { transition: color .2s, letter-spacing .2s; }
.lesson-card:hover .num { letter-spacing: 0.16em; }

/* mag-tilt states are set via CSS custom properties from JS */
.lesson-card.tilt {
  transform:
    perspective(900px)
    rotateX(var(--tx, 0deg))
    rotateY(var(--ty, 0deg))
    translate3d(0, -4px, 0);
  box-shadow:
    calc(var(--sx, 0px)) 10px 32px rgba(18,24,40,.10),
    calc(var(--sx, 0px)) 4px 10px rgba(18,24,40,.05);
  border-color: var(--cyan-ink);
}

/* ============================================================
 * 06 — TOPBAR: shrink on scroll, XP pill burst
 * ============================================================ */

.topbar { transition: padding .2s ease, backdrop-filter .2s ease, background .2s ease; }
.topbar.shrunk { box-shadow: 0 1px 0 var(--rule), 0 4px 18px rgba(18,24,40,.05); }
.topbar.shrunk .topbar-inner { padding-top: 9px; padding-bottom: 9px; }

.xp-pill {
  transition: transform .18s cubic-bezier(.2,.7,.2,1), box-shadow .25s;
  position: relative;
}
.xp-pill.xp-bump { transform: scale(1.08); box-shadow: 0 0 0 5px var(--cyan-wash); }
.xp-pill .spark  { transition: transform .35s cubic-bezier(.2,.7,.2,1); }
.xp-pill.xp-bump .spark { transform: rotate(45deg) scale(1.2); }

/* Floating "+NN XP" burst. JS injects .xp-burst elements next to the pill. */
.xp-burst {
  position: absolute;
  right: 10px; top: -4px;
  font-family: var(--mono);
  font-weight: 700;
  font-size: .72rem;
  color: var(--cyan-deep);
  pointer-events: none;
  animation: m-burst 900ms cubic-bezier(.2,.7,.2,1) forwards;
}

/* ============================================================
 * 07 — LESSON SHELL: sticky progress rail, scroll progress bar
 * ============================================================ */

.topbar .reading-rail {
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 2px;
  background: transparent;
  pointer-events: none;
}
.topbar .reading-rail > span {
  display: block; height: 100%;
  width: var(--read, 0%);
  background: linear-gradient(90deg, var(--cyan), var(--cyan-ink));
  transition: width .15s linear;
  box-shadow: 0 0 10px rgba(57,170,235,.4);
}

/* TOC: dotted vertical line + active pip */
.lesson-sidebar .toc-head {
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 14px;
}
.lesson-sidebar ul {
  list-style: none; margin: 0; padding: 0;
  position: relative;
}
.lesson-sidebar ul::before {
  content: '';
  position: absolute;
  left: 10px; top: 6px; bottom: 6px;
  width: 2px;
  background: linear-gradient(180deg, var(--rule) 0%, var(--rule-2) 50%, var(--rule) 100%);
  border-radius: 2px;
}
.lesson-sidebar li { position: relative; margin: 0; padding: 0; }
.lesson-sidebar li a {
  display: flex; align-items: center; gap: 12px;
  padding: 6px 0 6px 28px;
  font-family: var(--mono);
  font-size: .82rem;
  color: var(--ink-3);
  border-radius: 4px;
  transition: color .2s;
  position: relative;
}
.lesson-sidebar li a .n {
  font-size: .7rem;
  color: var(--ink-4);
  letter-spacing: .08em;
}
.lesson-sidebar li a::before {
  /* pip on the rail */
  content: '';
  position: absolute;
  left: 6px; top: 50%;
  width: 10px; height: 10px;
  margin-top: -5px;
  border-radius: 50%;
  background: var(--paper);
  border: 1.5px solid var(--rule-2);
  transition: all .25s cubic-bezier(.2,.7,.2,1);
}
.lesson-sidebar li a:hover { color: var(--ink); text-decoration: none; }
.lesson-sidebar li a:hover::before { border-color: var(--cyan-ink); }
.lesson-sidebar li a.active {
  color: var(--ink);
  font-weight: 600;
}
.lesson-sidebar li a.active::before {
  background: var(--cyan);
  border-color: var(--cyan-deep);
  box-shadow: 0 0 0 4px color-mix(in oklch, var(--cyan) 25%, transparent);
}
.lesson-sidebar li a.active .n { color: var(--cyan-deep); }

/* Lesson hero eyebrow: animated prompt */
.lesson-hero .lesson-num {
  position: relative; display: inline-flex; align-items: center; gap: 10px;
}
.lesson-hero .lesson-num::before {
  content: '$';
  color: var(--cyan-ink);
  animation: m-cursor 1.1s step-end infinite;
}

/* Lesson content section entrance */
.lesson-content > section { opacity: 0; transform: translate3d(0, 12px, 0); will-change: transform, opacity; }
.lesson-content > section.in { animation: m-rise .6s cubic-bezier(.2,.7,.2,1) both; }

/* ============================================================
 * 08 — WIDGET POLISH
 * ============================================================ */

/* Common widget appear */
.w { animation: m-scale-in .5s cubic-bezier(.2,.7,.2,1) both; }
.w .w-head .w-xp { transition: all .3s cubic-bezier(.2,.7,.2,1); }
.w .w-head .w-xp.earned {
  animation: m-pop .55s cubic-bezier(.2,.7,.2,1);
}

/* Quiz */
.quiz-opt {
  position: relative;
  overflow: hidden;
  transition: all .2s cubic-bezier(.2,.7,.2,1);
}
.quiz-opt::before {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(90deg, transparent, color-mix(in oklch, var(--cyan) 15%, transparent), transparent);
  transform: translateX(-120%);
  transition: transform .5s cubic-bezier(.2,.7,.2,1);
  pointer-events: none;
}
.quiz-opt:not(:disabled):hover::before { transform: translateX(120%); }
.quiz-opt:not(:disabled):hover {
  border-color: var(--cyan-ink);
  transform: translate3d(0, -1px, 0);
}
.quiz-opt.wrong {
  animation: m-shake .5s cubic-bezier(.36,.07,.19,.97);
  border-color: color-mix(in oklch, var(--bad) 40%, var(--rule));
  background: color-mix(in oklch, var(--bad) 7%, var(--paper));
}
.quiz-opt.correct {
  border-color: color-mix(in oklch, var(--ok) 40%, var(--rule));
  background: color-mix(in oklch, var(--ok) 8%, var(--paper));
  position: relative;
}
.quiz-opt.correct::after {
  /* draw-in green check */
  content: '';
  position: absolute; right: 14px; top: 50%; margin-top: -7px;
  width: 14px; height: 14px;
  background: var(--ok);
  -webkit-mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 14 14'><path d='M2 7 L6 11 L12 3' stroke='black' stroke-width='2.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>") center / contain no-repeat;
          mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 14 14'><path d='M2 7 L6 11 L12 3' stroke='black' stroke-width='2.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>") center / contain no-repeat;
  animation: m-pop .4s cubic-bezier(.2,.7,.2,1);
}

.quiz-explanation {
  animation: m-rise .45s cubic-bezier(.2,.7,.2,1) both;
}

/* Diff — stagger rows */
.diff-line { opacity: 0; animation: m-rise-left .3s cubic-bezier(.2,.7,.2,1) forwards; }
.diff-line:nth-child(1)  { animation-delay: 30ms; }
.diff-line:nth-child(2)  { animation-delay: 60ms; }
.diff-line:nth-child(3)  { animation-delay: 90ms; }
.diff-line:nth-child(4)  { animation-delay: 120ms; }
.diff-line:nth-child(5)  { animation-delay: 150ms; }
.diff-line:nth-child(6)  { animation-delay: 180ms; }
.diff-line:nth-child(7)  { animation-delay: 210ms; }
.diff-line:nth-child(8)  { animation-delay: 240ms; }
.diff-line:nth-child(n+9) { animation-delay: 280ms; }
.diff-line.add { position: relative; }
.diff-line.add::before {
  content: ''; position: absolute; left: 0; top: 0; bottom: 0;
  width: 2px; background: var(--ok);
  transform: scaleY(0); transform-origin: top;
  animation: m-rail-travel .4s cubic-bezier(.2,.7,.2,1) .1s forwards;
}
.diff-line.del { position: relative; }
.diff-line.del::before {
  content: ''; position: absolute; left: 0; top: 0; bottom: 0;
  width: 2px; background: var(--bad);
  transform: scaleY(0); transform-origin: top;
  animation: m-rail-travel .4s cubic-bezier(.2,.7,.2,1) .1s forwards;
}

/* Terminal demo — typewriter line entrance */
.tdemo-line {
  opacity: 0;
  animation: m-rise-left .35s cubic-bezier(.2,.7,.2,1) forwards;
}

/* "● running" status pulse */
.tdemo-head .title .running-dot {
  display: inline-block;
  width: .55rem; height: .55rem;
  border-radius: 50%;
  background: oklch(.82 .15 150);
  box-shadow: 0 0 10px oklch(.82 .15 150);
  animation: m-glow-pulse 1.2s ease-in-out infinite;
}

/* Flashcards — stage with 3D perspective */
.flashcards { perspective: 1400px; }
.flashcard {
  transform-style: preserve-3d;
  transition: transform .7s cubic-bezier(.3, 1.3, .4, 1);
  position: relative;
  cursor: pointer;
}
.flashcard.flipped { transform: rotateY(180deg); }
.flashcard-face.front { transform: rotateY(0deg); backface-visibility: hidden; }
.flashcard-face.back  { transform: rotateY(180deg); backface-visibility: hidden; position: absolute; inset: 0; }
.flashcard::after {
  /* scan-line gets wiped across on reveal */
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(90deg, transparent, color-mix(in oklch, var(--cyan) 18%, transparent), transparent);
  transform: translateX(-120%);
  pointer-events: none;
  border-radius: inherit;
}
.flashcard.flipping::after { animation: m-scan .6s cubic-bezier(.2,.7,.2,1); }

/* TaskSpec toggles — press down */
.spec-toggle {
  transition: transform .18s cubic-bezier(.2,.7,.2,1), border-color .2s, background .2s;
}
.spec-toggle:hover { transform: translate3d(2px, 0, 0); border-color: var(--cyan-ink); }
.spec-toggle.on .tog {
  background: var(--cyan);
  border-color: var(--cyan-deep);
  box-shadow: 0 0 0 4px color-mix(in oklch, var(--cyan) 22%, transparent);
}
.spec-toggle.on .tog::after {
  content: ''; position: absolute; inset: 0;
  -webkit-mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 14 14'><path d='M2 7 L6 11 L12 3' stroke='black' stroke-width='2.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>") center / contain no-repeat;
          mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 14 14'><path d='M2 7 L6 11 L12 3' stroke='black' stroke-width='2.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/></svg>") center / contain no-repeat;
  background: white;
  animation: m-pop .35s cubic-bezier(.2,.7,.2,1);
}
.spec-score .bar > div {
  background: linear-gradient(90deg, var(--cyan), var(--cyan-ink));
  background-size: 200% 100%;
  animation: m-progress-indeterminate 2.4s linear infinite;
  transition: width .45s cubic-bezier(.2,.7,.2,1);
}
.spec-right { position: relative; overflow: hidden; }
.spec-right::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent, color-mix(in oklch, var(--cyan) 4%, transparent));
  pointer-events: none;
}

/* ============================================================
 * 09 — HERO LOOP DIAGRAM: flowing particles (SVG overlay)
 *   Rendered by motion.js into .hero-diagram.
 * ============================================================ */

.hd-flow {
  position: absolute; inset: 0;
  pointer-events: none;
  z-index: 0;
}
.hd-flow path {
  fill: none;
  stroke: color-mix(in oklch, var(--cyan) 55%, transparent);
  stroke-width: 1.5;
  stroke-dasharray: 4 6;
  animation: m-flow-dash 3s linear infinite;
  opacity: .55;
}
.hd-flow circle.particle {
  fill: var(--cyan);
  filter: drop-shadow(0 0 4px var(--cyan));
  animation: m-particle 3.2s linear infinite;
}
.hd-flow circle.particle.p2 { animation-delay: -1.1s; }
.hd-flow circle.particle.p3 { animation-delay: -2.2s; }
.hero-diagram { position: relative; }
.hd-col { position: relative; z-index: 1; }
.hd-body { position: relative; }

/* ============================================================
 * 10 — TRACK HEADS & PROGRESS BARS
 * ============================================================ */

.track-head h2 { position: relative; display: inline-block; }
.track-head h2::after {
  content: '';
  position: absolute; left: 0; right: 0; bottom: -6px;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan) 0%, transparent 60%);
  transform: scaleX(0); transform-origin: left;
  transition: transform .6s cubic-bezier(.2,.7,.2,1);
}
.track:hover .track-head h2::after,
.track.in .track-head h2::after { transform: scaleX(1); }

.track-prog-bar > div {
  background: linear-gradient(90deg, var(--cyan), var(--cyan-ink));
  position: relative;
}
.track-prog-bar > div::after {
  /* moving gloss */
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,.55), transparent);
  animation: m-stripe 1.6s linear infinite;
  mix-blend-mode: overlay;
}

/* ============================================================
 * 11 — BADGES: earned gets a pulse & sparkle
 * ============================================================ */

.badge.earned {
  position: relative;
  animation: m-pop .55s cubic-bezier(.2,.7,.2,1);
}
.badge.earned::after {
  content: '';
  position: absolute; top: -2px; right: -2px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 10px var(--cyan);
  animation: m-glow-pulse 2s ease-in-out infinite;
}

/* ============================================================
 * 12 — BUTTONS & LINKS
 * ============================================================ */

.btn { position: relative; overflow: hidden; }
.btn::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(120deg, transparent 30%, rgba(255,255,255,.25) 50%, transparent 70%);
  transform: translateX(-120%);
  transition: transform .7s cubic-bezier(.2,.7,.2,1);
  pointer-events: none;
}
.btn:hover::after { transform: translateX(120%); }
.btn.primary:hover { box-shadow: 0 10px 24px rgba(18,24,40,.18); }
.btn.cyan:hover { box-shadow: 0 10px 24px rgba(57,170,235,.32); }

.btn.primary, .btn.cyan {
  /* subtle idle breathing */
  animation: m-glow-pulse 5s ease-in-out infinite;
}

/* ============================================================
 * 13 — FOOTER
 * ============================================================ */

.lesson-foot a { transition: transform .25s cubic-bezier(.2,.7,.2,1); }
.lesson-foot a:hover { transform: translate3d(0, -2px, 0); }
.lesson-foot a.next:hover { transform: translate3d(4px, -2px, 0); }

#btn-complete:not(:disabled):hover {
  animation: m-glow-pulse 1.2s ease-in-out infinite;
}

/* ============================================================
 * 14 — PAGE BOOT & TRANSITIONS
 * ============================================================ */

body { animation: m-boot .4s cubic-bezier(.2,.7,.2,1) both; }

@view-transition { navigation: auto; }
::view-transition-old(root)   { animation: m-fade-out .24s cubic-bezier(.2,.7,.2,1) both; }
::view-transition-new(root)   { animation: m-fade-in  .3s  cubic-bezier(.2,.7,.2,1) both; }
@keyframes m-fade-out { to { opacity: 0; transform: translateY(-6px); } }
@keyframes m-fade-in  { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; } }

/* ============================================================
 * 15 — REDUCED MOTION
 * ============================================================ */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
  .hero .hero-grid-bg, .hero .hero-scanline, .hd-flow path, .hd-flow circle { animation: none !important; }
  .reveal, .reveal-left, .reveal-scale,
  .reveal-stagger > *, .lesson-content > section { opacity: 1 !important; transform: none !important; }
  .btn.primary, .btn.cyan { animation: none !important; }
}

/* ============================================================
 * 16 — WIDGET EXTRAS introduced in widgets.js v2
 * ============================================================ */

/* terminal status dot */
.tdemo-head .title { display: inline-flex; align-items: center; gap: 6px; }
.tdemo-head .title .status-dot {
  display: inline-block;
  width: .55rem; height: .55rem;
  border-radius: 50%;
  background: oklch(.6 .01 240);
  transition: background .25s, box-shadow .25s;
}
.tdemo-head .title .status-dot.running {
  animation: m-glow-pulse 1.2s ease-in-out infinite;
}
.tdemo-head .title .status-dot.done {
  animation: none;
}

/* terminal speed selector */
.tdemo-ctrl { display: flex; align-items: center; gap: 10px; margin-top: 10px; flex-wrap: wrap; }
.tdemo-speed { margin-left: auto; display: inline-flex; align-items: center; gap: 8px; }
.tdemo-speed select {
  width: auto;
  padding: 5px 8px;
  font-size: .76rem;
  background: var(--paper);
  color: var(--ink-2);
  border: 1px solid var(--rule-2);
  border-radius: 4px;
  font-family: var(--mono);
}
.tdemo-speed label { font-family: var(--mono); }

/* inline typewriter caret while typing */
.type-caret {
  display: inline-block;
  margin-left: 1px;
  color: oklch(.82 .15 210);
  animation: m-cursor .85s step-end infinite;
  font-weight: 500;
}

/* TaskSpec tier color */
.spec-score .tier { color: var(--ink-3); text-transform: uppercase; font-size: .68rem; letter-spacing: .1em; transition: color .25s; }
.spec-score .tier[data-tier="weak"]   { color: var(--ink-4); }
.spec-score .tier[data-tier="meh"]    { color: var(--warn); }
.spec-score .tier[data-tier="strong"] { color: var(--ok); font-weight: 700; }

/* Flashcard progress dots */
.flash-dots {
  display: flex; gap: 6px; justify-content: center;
  margin: 12px 0 0;
}
.flash-dots .fd {
  display: inline-block;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--rule-2);
  transition: all .25s cubic-bezier(.2,.7,.2,1);
}
.flash-dots .fd.seen { background: color-mix(in oklch, var(--cyan) 50%, var(--rule-2)); }
.flash-dots .fd.cur {
  background: var(--cyan);
  width: 18px; border-radius: 4px;
  box-shadow: 0 0 0 3px color-mix(in oklch, var(--cyan) 18%, transparent);
}

/* Compare hover outline */
.compare-col { transition: transform .25s cubic-bezier(.2,.7,.2,1), box-shadow .25s; }
.compare-col:hover {
  transform: translate3d(0, -2px, 0);
  box-shadow: 0 8px 24px rgba(18,24,40,.06);
}
.compare-col.good:hover { border-color: var(--ok); }
.compare-col.bad:hover  { border-color: var(--bad); }

/* Diff line hover highlight */
.diff-line { transition: background .2s; }
.diff-line:hover {
  background: color-mix(in oklch, var(--cyan) 4%, transparent);
}


/* ============================================================
 * 17 — v3 GLOBAL POLISH PASS
 * Fixes the "unfinished dashed box" feel on quiz options,
 * elevates buttons, introduces radio-fill animation,
 * adds global scene transition, unifies interactive states.
 * ============================================================ */

/* ---- Quiz options: turn into polished radio-style choices ---- */
.quiz-opts { display: grid; gap: 10px; margin-top: 12px; }
.quiz-opt {
  position: relative;
  display: grid;
  grid-template-columns: 28px 1fr;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 14px 18px 14px 14px;
  text-align: left;
  background: var(--paper);
  border: 1px solid var(--rule-2);
  border-radius: 10px;
  font-size: .92rem;
  line-height: 1.45;
  color: var(--ink-2);
  cursor: pointer;
  transition: transform .18s cubic-bezier(.2,.7,.2,1),
              border-color .2s, background .2s, box-shadow .2s;
  overflow: hidden;
}
.quiz-opt::before {
  /* animated hover sheen */
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(120deg, transparent 20%,
    color-mix(in oklch, var(--cyan) 8%, transparent) 50%,
    transparent 80%);
  transform: translateX(-120%);
  transition: transform .6s cubic-bezier(.2,.7,.2,1);
  pointer-events: none;
}
.quiz-opt:hover:not(:disabled)::before { transform: translateX(120%); }
.quiz-opt:hover:not(:disabled) {
  border-color: color-mix(in oklch, var(--cyan) 60%, var(--rule-2));
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(18,24,40,.05);
}
.quiz-opt:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}
.quiz-opt .letter {
  display: inline-flex;
  width: 28px; height: 28px;
  align-items: center; justify-content: center;
  border: 1.5px solid var(--rule-2);
  border-radius: 50%;
  font-family: var(--mono);
  font-weight: 700;
  font-size: .72rem;
  color: var(--ink-3);
  background: var(--canvas);
  position: relative;
  transition: all .2s cubic-bezier(.2,.7,.2,1);
}
.quiz-opt:hover:not(:disabled) .letter {
  border-color: var(--cyan);
  color: var(--cyan);
  transform: scale(1.06);
}
/* correct state */
.quiz-opt.correct {
  border-color: var(--ok);
  background: color-mix(in oklch, var(--ok) 7%, var(--paper));
  animation: m-correct-glow .6s ease-out;
}
.quiz-opt.correct .letter {
  background: var(--ok);
  color: white;
  border-color: var(--ok);
  transform: scale(1.1);
}
.quiz-opt.correct .letter::after {
  content: '✓';
  position: absolute;
  inset: 0;
  display: grid; place-items: center;
  color: white;
  font-size: .9rem;
  font-weight: 700;
  animation: m-check-draw .4s cubic-bezier(.2,.7,.2,1) .1s both;
}
/* wrong state */
.quiz-opt.wrong {
  border-color: var(--bad);
  background: color-mix(in oklch, var(--bad) 5%, var(--paper));
  animation: m-shake .4s cubic-bezier(.36,.07,.19,.97);
}
.quiz-opt.wrong .letter {
  background: var(--bad);
  color: white;
  border-color: var(--bad);
}
.quiz-opt:disabled {
  cursor: default;
  opacity: .62;
}
.quiz-opt.correct:disabled,
.quiz-opt.wrong:disabled { opacity: 1; }

@keyframes m-correct-glow {
  0% { box-shadow: 0 0 0 0 color-mix(in oklch, var(--ok) 50%, transparent); }
  60% { box-shadow: 0 0 0 14px transparent; }
  100% { box-shadow: 0 0 0 0 transparent; }
}
@keyframes m-shake {
  10%, 90% { transform: translate3d(-1px,0,0); }
  20%, 80% { transform: translate3d(2px,0,0); }
  30%, 50%, 70% { transform: translate3d(-3px,0,0); }
  40%, 60% { transform: translate3d(3px,0,0); }
}
@keyframes m-check-draw {
  from { transform: scale(.3) rotate(-20deg); opacity: 0; }
  to   { transform: scale(1) rotate(0);      opacity: 1; }
}

/* ---- Quiz explanation box ---- */
.quiz-explanation {
  margin-top: 14px;
  padding: 14px 16px;
  background: color-mix(in oklch, var(--cyan) 5%, var(--paper));
  border-left: 3px solid var(--cyan);
  border-radius: 0 8px 8px 0;
  font-size: .9rem;
  line-height: 1.55;
  color: var(--ink-2);
  animation: m-explanation-in .5s cubic-bezier(.2,.7,.2,1) both;
}
@keyframes m-explanation-in {
  from { opacity: 0; transform: translateY(-6px); max-height: 0; padding-top: 0; padding-bottom: 0; }
  to   { opacity: 1; transform: translateY(0);    max-height: 400px; }
}

/* ---- TaskSpec toggle polish (replace the "unfinished box" feel) ---- */
.spec-toggle {
  position: relative;
  width: 100%;
  display: grid;
  grid-template-columns: 36px 1fr;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  background: var(--paper);
  border: 1px solid var(--rule-2);
  border-radius: 10px;
  margin-bottom: 8px;
  text-align: left;
  cursor: pointer;
  font-family: inherit;
  transition: all .25s cubic-bezier(.2,.7,.2,1);
}
.spec-toggle:hover { border-color: color-mix(in oklch, var(--cyan) 50%, var(--rule-2)); transform: translateY(-1px); }
.spec-toggle .tog {
  position: relative;
  width: 36px;
  height: 20px;
  border-radius: 20px;
  background: var(--rule-2);
  transition: background .25s;
  flex-shrink: 0;
}
.spec-toggle .tog::after {
  content: '';
  position: absolute;
  top: 2px; left: 2px;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: white;
  box-shadow: 0 1px 3px rgba(0,0,0,.2);
  transition: left .25s cubic-bezier(.2,.7,.2,1), box-shadow .25s;
}
.spec-toggle.on .tog {
  background: var(--cyan);
}
.spec-toggle.on .tog::after {
  left: 18px;
  box-shadow: 0 1px 3px rgba(18,24,40,.35), 0 0 8px color-mix(in oklch, var(--cyan) 40%, transparent);
}
.spec-toggle .body .lbl { font-weight: 600; color: var(--ink-1); font-size: .88rem; }
.spec-toggle .body .hint { font-size: .76rem; color: var(--ink-3); margin-top: 2px; line-height: 1.45; }
.spec-toggle.on { border-color: color-mix(in oklch, var(--cyan) 40%, var(--rule-2)); background: color-mix(in oklch, var(--cyan) 3%, var(--paper)); }

/* ---- Unified button polish ---- */
.btn {
  position: relative;
  overflow: hidden;
}
.btn::after {
  /* ripple on click */
  content: '';
  position: absolute;
  left: var(--rx, 50%); top: var(--ry, 50%);
  width: 0; height: 0;
  border-radius: 50%;
  background: currentColor;
  opacity: 0;
  transform: translate(-50%, -50%);
  transition: width .4s, height .4s, opacity .6s;
  pointer-events: none;
}
.btn:active::after {
  width: 260px; height: 260px;
  opacity: .15;
  transition: width 0s, height 0s, opacity 0s;
}
.btn.primary:hover { background: color-mix(in oklch, var(--ink-1) 92%, var(--cyan)); transform: translateY(-1px); }

/* ---- Page transition (scene change) ---- */
html.cx-page-leaving body {
  animation: m-page-leave .32s cubic-bezier(.2,.7,.2,1) forwards;
}
html.cx-page-entering body {
  animation: m-page-enter .42s cubic-bezier(.2,.7,.2,1) both;
}
@keyframes m-page-leave {
  from { opacity: 1; filter: blur(0); }
  to   { opacity: 0; filter: blur(6px); transform: translateY(-14px); }
}
@keyframes m-page-enter {
  from { opacity: 0; filter: blur(10px); transform: translateY(18px); }
  to   { opacity: 1; filter: blur(0);    transform: translateY(0); }
}

/* ---- Bespoke widget host frame (used by L*.js widgets) ---- */
.bespoke-host {
  margin: 28px 0;
  padding: 0;
  background: var(--paper);
  border: 1px solid var(--rule-2);
  border-radius: 12px;
  overflow: hidden;
  position: relative;
  box-shadow: 0 2px 0 var(--rule-2), 0 20px 40px -30px rgba(18,24,40,.25);
}
.bespoke-host::before {
  /* subtle inner top accent */
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  opacity: .6;
}
.bespoke-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 18px;
  font-family: var(--mono);
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--ink-3);
  text-transform: uppercase;
  border-bottom: 1px solid var(--rule-2);
  background: linear-gradient(180deg,
    color-mix(in oklch, var(--cyan) 3%, var(--paper)),
    var(--paper));
}
.bespoke-header .kind {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 10px;
  background: var(--canvas);
  border: 1px solid var(--rule-2);
  border-radius: 4px;
  font-weight: 700;
  color: var(--cyan);
}
.bespoke-header .kind::before {
  content: '';
  display: inline-block;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--cyan);
  animation: m-glow-pulse 2s ease-in-out infinite;
}
.bespoke-body { padding: 24px; min-height: 360px; }

/* ---- XP celebration flash ---- */
.xp-flash {
  position: fixed;
  left: var(--x, 50%);
  top: var(--y, 50%);
  transform: translate(-50%, -50%);
  font-family: var(--mono);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--cyan);
  pointer-events: none;
  z-index: 10000;
  animation: m-xp-float 1.2s cubic-bezier(.2,.7,.2,1) forwards;
  text-shadow: 0 0 8px color-mix(in oklch, var(--cyan) 60%, transparent);
}
@keyframes m-xp-float {
  0%   { opacity: 0; transform: translate(-50%, -50%) scale(.5); }
  20%  { opacity: 1; transform: translate(-50%, -50%) scale(1.2); }
  100% { opacity: 0; transform: translate(-50%, -80%) scale(1); }
}

/* ---- Lesson completion celebration ---- */
@keyframes m-celebrate-sweep {
  0%   { background-position: -200% 0; }
  100% { background-position:  200% 0; }
}
.lesson-complete-flash {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9998;
  background: linear-gradient(120deg,
    transparent 30%,
    color-mix(in oklch, var(--cyan) 20%, transparent) 50%,
    transparent 70%);
  background-size: 200% 100%;
  animation: m-celebrate-sweep 1.4s cubic-bezier(.2,.7,.2,1);
}

/* ---- Ambient particle layer (homepage) ---- */
.particle-layer {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: -1;
  opacity: .5;
}

/* ---- TOC active pip pulse ---- */
.lesson-toc li.cur .pip {
  animation: m-pip-pulse 2s ease-in-out infinite;
}
@keyframes m-pip-pulse {
  0%, 100% { box-shadow: 0 0 0 0 color-mix(in oklch, var(--cyan) 50%, transparent); }
  50%      { box-shadow: 0 0 0 6px transparent; }
}

/* ---- Fix flashcard perspective depth ---- */
.flash-stage { perspective: 1200px; }
.flashcard {
  transform-style: preserve-3d;
  transition: transform .62s cubic-bezier(.2,.8,.2,1);
}
.flashcard.flipped { transform: rotateY(180deg); }
.flashcard .back   { transform: rotateY(180deg); backface-visibility: hidden; -webkit-backface-visibility: hidden; }
.flashcard .front  { backface-visibility: hidden; -webkit-backface-visibility: hidden; }
.flashcard.flipping {
  animation: m-card-pop .62s cubic-bezier(.2,.8,.2,1);
}
@keyframes m-card-pop {
  50% { transform: rotateY(90deg) scale(1.04); }
}

/* ---- Reduced-motion safeguards for the new stuff ---- */
@media (prefers-reduced-motion: reduce) {
  .quiz-opt::before,
  .flashcard.flipping,
  .lesson-complete-flash,
  .xp-flash,
  .particle-layer {
    animation: none !important;
    transition: none !important;
  }
}