/* ════════════════════════════════════════════════════════════════
   MACALINAO STUDIO · AI LEARNING COURSE · V2
   Warm paper · Charcoal ink · Signal orange
   Dynamic edition — animated, interactive, homogenized components
   ════════════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@300;400;500;600;700;800&family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  --paper:   #ebe7dd;
  --paper-2: #e3dfd4;
  --paper-3: #d8d3c6;
  --ink:     #0e0e0c;
  --ink-2:   #5a574f;
  --ink-3:   #908b7f;
  --ink-4:   #b9b4a8;
  --line:    rgba(14,14,12,.10);
  --line-2:  rgba(14,14,12,.22);
  --dark:    #14130f;
  --dark-2:  #1d1c17;
  --dark-3:  #25241f;
  --accent:  #ff4d00;
  --accent-2:#cc3d00;
  --accent-soft: rgba(255,77,0,.08);
  --ok:      #2e8b57;

  /* lesson hues — cycled across concept cards */
  --hue-a: #ff4d00;  /* signal orange  */
  --hue-b: #1d9e75;  /* teal           */
  --hue-c: #2f7fc4;  /* blue           */
  --hue-d: #7f77dd;  /* purple         */

  --display: 'Manrope', system-ui, sans-serif;
  --text:    'Inter', system-ui, sans-serif;
  --mono:    'JetBrains Mono', 'SF Mono', Consolas, monospace;
  --ease:    cubic-bezier(.22,.8,.1,1);
  --ease-2:  cubic-bezier(.76,0,.24,1);
  --ease-3:  cubic-bezier(.34,1.56,.64,1);

  --pad-x: 40px;
  --max-w: 1340px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--text);
  font-size: 15.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; background: none; border: 0; cursor: pointer; color: inherit; }
img, svg, video { display: block; max-width: 100%; }
ul { list-style: none; }
::selection { background: var(--accent); color: var(--paper); }

/* paper grain */
body::before {
  content: ''; position: fixed; inset: 0; pointer-events: none; z-index: 1;
  background-image: radial-gradient(rgba(14,14,12,.025) 1px, transparent 1px);
  background-size: 3px 3px; mix-blend-mode: multiply; opacity: .5;
}

.lbl {
  font-family: var(--mono); font-size: 11px; font-weight: 500;
  letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3);
}

/* ── scroll progress bar ── */
.scroll-progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: var(--accent); z-index: 400; transition: width .08s linear;
}

/* ════════════════ NAV ════════════════ */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 300;
  display: flex; align-items: center; justify-content: space-between; gap: 18px;
  height: 64px; padding: 0 var(--pad-x);
  border-bottom: 1px solid transparent;
  transition: background .35s var(--ease), border-color .35s, backdrop-filter .35s;
}
.nav.scrolled {
  background: rgba(235,231,221,.88);
  backdrop-filter: blur(14px) saturate(120%);
  border-color: var(--line);
}
.nav-brand { display: flex; align-items: baseline; gap: 14px; font-family: var(--display); font-size: 15px; }
.nav-brand strong { font-weight: 800; }
.nav-brand .crumb { font-family: var(--mono); font-size: 11px; color: var(--ink-3); letter-spacing: .06em; }
.nav-links { display: flex; gap: 22px; font-family: var(--mono); font-size: 11.5px; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-2); }
.nav-links a { position: relative; padding: 4px 0; transition: color .25s; }
.nav-links a:hover { color: var(--ink); }
.nav-links a::after {
  content: ''; position: absolute; left: 0; bottom: 0; height: 1.5px; width: 0;
  background: var(--accent); transition: width .3s var(--ease);
}
.nav-links a:hover::after { width: 100%; }
.nav-right { display: flex; align-items: center; gap: 14px; }
.progress-chip {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .08em;
  padding: 6px 12px; border: 1px solid var(--line-2); border-radius: 100px;
  display: flex; align-items: center; gap: 8px; color: var(--ink-2);
  background: var(--paper-2);
}
.progress-chip .ring { width: 14px; height: 14px; transform: rotate(-90deg); }
.progress-chip .ring circle { fill: none; stroke-width: 3; }
.progress-chip .ring .bg { stroke: var(--line-2); }
.progress-chip .ring .fg { stroke: var(--accent); stroke-linecap: round; transition: stroke-dasharray .6s var(--ease); }
.nav-cta {
  font-family: var(--mono); font-size: 11px; letter-spacing: .1em; text-transform: uppercase;
  padding: 9px 16px; background: var(--ink); color: var(--paper); border-radius: 2px;
  transition: background .25s, transform .25s var(--ease);
}
.nav-cta:hover { background: var(--accent); transform: translateY(-1px); }

@media (max-width: 880px) {
  :root { --pad-x: 20px; }
  .nav-links { display: none; }
}

/* ════════════════ REVEAL ANIMATIONS ════════════════ */
.rv { opacity: 0; transform: translateY(26px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.rv.in { opacity: 1; transform: none; }
.rv-d1 { transition-delay: .08s; } .rv-d2 { transition-delay: .16s; }
.rv-d3 { transition-delay: .24s; } .rv-d4 { transition-delay: .32s; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001s !important; transition-duration: .001s !important; }
  .rv { opacity: 1; transform: none; }
}

/* ════════════════ COURSE HOME — HERO ════════════════ */
.hero {
  position: relative; min-height: 92vh;
  display: flex; flex-direction: column; justify-content: center;
  padding: 130px var(--pad-x) 70px; max-width: var(--max-w); margin: 0 auto;
}
.hero-canvas { position: absolute; inset: 0; z-index: 0; opacity: .55; }
.hero > * { position: relative; z-index: 2; }
.hero-eyebrow { display: flex; align-items: center; gap: 14px; margin-bottom: 26px; }
.hero-eyebrow .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); animation: pulse-dot 2.2s infinite; }
@keyframes pulse-dot { 0%,100% { box-shadow: 0 0 0 0 rgba(255,77,0,.4); } 50% { box-shadow: 0 0 0 9px rgba(255,77,0,0); } }
.hero h1 {
  font-family: var(--display); font-weight: 800;
  font-size: clamp(44px, 7.2vw, 96px); line-height: 1.02; letter-spacing: -.035em;
  max-width: 13ch;
}
.hero h1 em { font-style: italic; font-weight: 300; color: var(--accent); }
.hero-sub { margin-top: 28px; max-width: 56ch; font-size: 17px; color: var(--ink-2); }
.hero-ctas { display: flex; gap: 14px; margin-top: 40px; flex-wrap: wrap; }
.btn-primary, .btn-ghost {
  font-family: var(--mono); font-size: 12px; letter-spacing: .12em; text-transform: uppercase;
  padding: 15px 26px; border-radius: 2px; display: inline-flex; align-items: center; gap: 10px;
  transition: transform .3s var(--ease), background .25s, color .25s, border-color .25s;
}
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { background: var(--accent); transform: translateY(-2px); }
.btn-ghost { border: 1px solid var(--line-2); color: var(--ink-2); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-2px); }

.hero-stats { display: flex; gap: 0; margin-top: 64px; border: 1px solid var(--line); background: var(--line); flex-wrap: wrap; }
.hstat { flex: 1 1 140px; background: var(--paper); padding: 22px 24px; }
.hstat .v { font-family: var(--display); font-weight: 800; font-size: 34px; letter-spacing: -.02em; }
.hstat .v span { color: var(--accent); }
.hstat .k { margin-top: 2px; font-family: var(--mono); font-size: 10px; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); }

/* ════════════════ FILTER BAR ════════════════ */
.filterbar {
  position: sticky; top: 64px; z-index: 250;
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  padding: 14px var(--pad-x);
  background: rgba(235,231,221,.92); backdrop-filter: blur(12px);
  border-top: 1px solid var(--line); border-bottom: 1px solid var(--line);
}
.fchip {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .1em; text-transform: uppercase;
  padding: 8px 15px; border: 1px solid var(--line-2); border-radius: 100px; color: var(--ink-2);
  transition: all .25s var(--ease);
}
.fchip:hover { border-color: var(--ink); color: var(--ink); transform: translateY(-1px); }
.fchip.on { background: var(--ink); border-color: var(--ink); color: var(--paper); }
.fchip.on.track-img { background: var(--hue-c); border-color: var(--hue-c); }
.fchip.on.track-vid { background: var(--hue-d); border-color: var(--hue-d); }
.fchip.on.track-voc { background: var(--hue-b); border-color: var(--hue-b); }
.fsearch {
  margin-left: auto; display: flex; align-items: center; gap: 8px;
  border: 1px solid var(--line-2); border-radius: 100px; padding: 7px 16px; min-width: 210px;
  background: var(--paper-2);
}
.fsearch input {
  border: 0; background: none; outline: none; font-family: var(--mono); font-size: 12px;
  color: var(--ink); width: 100%;
}
.fsearch input::placeholder { color: var(--ink-3); }

/* ════════════════ LEVELS ════════════════ */
.levels { max-width: var(--max-w); margin: 0 auto; padding: 30px var(--pad-x) 60px; }
.level { padding: 64px 0 10px; }
.level-head { display: grid; grid-template-columns: auto 1fr auto; align-items: end; gap: 26px; margin-bottom: 10px; }
.level-num {
  font-family: var(--display); font-weight: 800; font-size: 80px; line-height: .8;
  letter-spacing: -.04em; color: transparent; -webkit-text-stroke: 1.5px var(--ink-4);
}
.level.lv-on .level-num { color: var(--accent); -webkit-text-stroke: 0; }
.level-title { font-family: var(--display); font-weight: 800; font-size: clamp(26px, 3.4vw, 40px); letter-spacing: -.02em; line-height: 1.05; }
.level-title em { font-style: italic; font-weight: 300; color: var(--accent); }
.level-desc { font-size: 14px; color: var(--ink-2); max-width: 44ch; }
.level-meta { font-family: var(--mono); font-size: 10.5px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-3); text-align: right; }
.level-rule { height: 1px; background: var(--line-2); margin: 18px 0 30px; transform-origin: left; transform: scaleX(0); transition: transform 1.1s var(--ease-2); }
.rv.in .level-rule, .level-rule.in { transform: scaleX(1); }

/* lesson cards grid */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 18px; }
.lcard {
  position: relative; display: flex; flex-direction: column; gap: 12px;
  background: var(--paper-2); border: 1px solid var(--line);
  padding: 22px 22px 18px; min-height: 215px; overflow: hidden;
  transition: transform .4s var(--ease), box-shadow .4s var(--ease), border-color .3s, background .3s;
}
.lcard::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: var(--card-hue, var(--accent));
  transform: scaleX(0); transform-origin: left; transition: transform .45s var(--ease-2);
}
.lcard:hover { transform: translateY(-6px); box-shadow: 0 18px 40px -18px rgba(14,14,12,.28); border-color: var(--line-2); background: var(--paper); }
.lcard:hover::before { transform: scaleX(1); }
.lcard-top { display: flex; align-items: center; justify-content: space-between; }
.lcard-num { font-family: var(--mono); font-size: 11px; font-weight: 600; letter-spacing: .12em; color: var(--card-hue, var(--accent)); }
.lcard-done {
  width: 20px; height: 20px; border-radius: 50%; border: 1.5px solid var(--line-2);
  display: grid; place-items: center; font-size: 10px; color: transparent;
  transition: all .3s var(--ease-3);
}
.lcard.done .lcard-done { background: var(--ok); border-color: var(--ok); color: #fff; }
.lcard h3 { font-family: var(--display); font-weight: 700; font-size: 21px; line-height: 1.14; letter-spacing: -.015em; }
.lcard h3 em { font-style: italic; font-weight: 300; color: var(--card-hue, var(--accent)); }
.lcard p { font-size: 12.8px; line-height: 1.55; color: var(--ink-2); flex: 1; }
.lcard-foot {
  display: flex; align-items: center; gap: 10px; padding-top: 12px; border-top: 1px dashed var(--line-2);
  font-family: var(--mono); font-size: 9.5px; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-3);
}
.lcard-foot .grow { flex: 1; }
.tag-chip { display: inline-flex; align-items: center; gap: 4px; }
.tag-chip.demo { color: var(--accent); }
.tag-chip.audio { color: var(--hue-b); }
.mod-dots { display: inline-flex; gap: 3px; }
.mod-dots i { width: 6px; height: 6px; border-radius: 50%; background: var(--ink-4); }
.mod-dots i.t { background: var(--hue-a); } .mod-dots i.i { background: var(--hue-c); }
.mod-dots i.v { background: var(--hue-d); } .mod-dots i.s { background: var(--hue-b); }
.lcard .arrow {
  position: absolute; right: 18px; bottom: 14px; font-size: 16px; color: var(--card-hue, var(--accent));
  opacity: 0; transform: translateX(-8px); transition: all .35s var(--ease);
}
.lcard:hover .arrow { opacity: 1; transform: none; }
.lcard.hidden { display: none; }

/* track header cards tint */
.level[data-track="image"] { --card-hue: var(--hue-c); }
.level[data-track="video"] { --card-hue: var(--hue-d); }
.level[data-track="voice"] { --card-hue: var(--hue-b); }

/* ════════════════ COURSE MAP (SVG) ════════════════ */
.map-wrap { max-width: var(--max-w); margin: 0 auto; padding: 70px var(--pad-x) 20px; }
.map-frame { border: 1px solid var(--line); background: var(--paper-2); padding: 34px 30px 26px; position: relative; overflow: hidden; }
.map-frame svg { width: 100%; height: auto; }
.map-path { stroke-dasharray: 1600; stroke-dashoffset: 1600; }
.in .map-path { animation: draw-path 2.6s var(--ease-2) forwards .2s; }
@keyframes draw-path { to { stroke-dashoffset: 0; } }
.map-node { opacity: 0; transform: translateY(8px); transition: opacity .5s var(--ease), transform .5s var(--ease); }
.in .map-node { opacity: 1; transform: none; }
.in .map-node:nth-of-type(1) { transition-delay: .3s; } .in .map-node:nth-of-type(2) { transition-delay: .55s; }
.in .map-node:nth-of-type(3) { transition-delay: .8s; }  .in .map-node:nth-of-type(4) { transition-delay: 1.05s; }
.in .map-node:nth-of-type(5) { transition-delay: 1.3s; } .in .map-node:nth-of-type(6) { transition-delay: 1.55s; }
.in .map-node:nth-of-type(7) { transition-delay: 1.8s; } .in .map-node:nth-of-type(8) { transition-delay: 2.05s; }

/* ════════════════ LESSON PAGE ════════════════ */
.lesson-hero {
  position: relative; max-width: var(--max-w); margin: 0 auto;
  padding: 130px var(--pad-x) 40px;
}
.lesson-eyebrow { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 20px; }
.crumb-chip {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .12em; text-transform: uppercase;
  padding: 6px 13px; border: 1px solid var(--line-2); border-radius: 100px; color: var(--ink-2);
}
.crumb-chip.hot { background: var(--hue, var(--accent)); border-color: var(--hue, var(--accent)); color: var(--paper); }
.lesson-hero h1 {
  font-family: var(--display); font-weight: 800;
  font-size: clamp(36px, 5.6vw, 72px); line-height: 1.04; letter-spacing: -.03em; max-width: 18ch;
}
.lesson-hero h1 em { font-style: italic; font-weight: 300; color: var(--hue, var(--accent)); }
.lesson-tagline { margin-top: 18px; font-size: 17px; color: var(--ink-2); max-width: 58ch; }
.lesson-motif { position: absolute; right: var(--pad-x); top: 120px; width: 150px; opacity: .9; }
@media (max-width: 980px) { .lesson-motif { display: none; } }

/* hero motif animations */
.motif-float { animation: m-float 5s ease-in-out infinite; }
@keyframes m-float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }
.motif-dash { stroke-dasharray: 6 5; animation: m-dash 1.6s linear infinite; }
@keyframes m-dash { to { stroke-dashoffset: -22; } }
.motif-pulse { animation: m-pulse 2.4s ease-in-out infinite; transform-origin: center; transform-box: fill-box; }
@keyframes m-pulse { 0%,100% { opacity: .35; } 50% { opacity: 1; } }
.motif-spin { animation: m-spin 14s linear infinite; transform-origin: center; transform-box: fill-box; }
@keyframes m-spin { to { transform: rotate(360deg); } }

/* lesson map (section chips) */
.lesson-map {
  display: flex; gap: 8px; flex-wrap: wrap; margin-top: 34px;
}
.lm-chip {
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .08em;
  padding: 8px 14px; border: 1px solid var(--line-2); border-radius: 100px; color: var(--ink-2);
  display: inline-flex; align-items: center; gap: 8px;
  transition: all .3s var(--ease);
}
.lm-chip i { width: 6px; height: 6px; border-radius: 50%; background: var(--ink-4); transition: background .3s; }
.lm-chip:hover { border-color: var(--hue, var(--accent)); color: var(--ink); transform: translateY(-1px); }
.lm-chip.seen i { background: var(--ok); }
.lm-chip.now { border-color: var(--hue, var(--accent)); color: var(--ink); background: var(--accent-soft); }

/* hero figure */
.hero-figure {
  max-width: var(--max-w); margin: 26px auto 0; padding: 0 var(--pad-x);
}
.fig-frame {
  position: relative; border: 1px solid var(--line-2); background: var(--dark);
  overflow: hidden;
}
.fig-frame::after {
  content: attr(data-cap);
  position: absolute; left: 0; right: 0; bottom: 0;
  padding: 10px 18px; font-family: var(--mono); font-size: 10px; letter-spacing: .12em;
  text-transform: uppercase; color: rgba(235,231,221,.75);
  background: linear-gradient(transparent, rgba(14,14,12,.82));
}
.fig-frame img { width: 100%; height: auto; transform: scale(1.015); transition: transform 6s var(--ease); }
.fig-frame.in img { transform: scale(1.06); }

/* lesson body */
.lesson-body { max-width: 1000px; margin: 0 auto; padding: 40px var(--pad-x) 80px; position: relative; z-index: 2; }
.lsec { padding: 46px 0 8px; }
.lsec-head { display: flex; align-items: baseline; gap: 18px; margin-bottom: 26px; }
.lsec-head .num {
  font-family: var(--mono); font-size: 12px; font-weight: 600; color: var(--hue, var(--accent));
  letter-spacing: .1em; white-space: nowrap;
}
.lsec-head h2 { font-family: var(--display); font-weight: 800; font-size: clamp(24px, 3vw, 34px); letter-spacing: -.02em; line-height: 1.1; }
.lsec-head h2 em { font-style: italic; font-weight: 300; color: var(--hue, var(--accent)); }
.lsec-head .rule { flex: 1; height: 1px; background: var(--line-2); align-self: center; }

.prose { font-size: 15.5px; color: var(--ink-2); max-width: 70ch; margin-bottom: 18px; }
.prose strong, .prose b { color: var(--ink); }
.prose code, .ccard-body code {
  font-family: var(--mono); font-size: .88em; background: var(--paper-3);
  padding: 1px 6px; border-radius: 3px; color: var(--ink);
}

/* sub-label */
.sub-label {
  display: flex; align-items: center; gap: 14px; margin: 30px 0 16px;
  font-family: var(--mono); font-size: 11px; font-weight: 600; letter-spacing: .14em;
  text-transform: uppercase; color: var(--ink-2);
}
.sub-label::after { content: ''; flex: 1; height: 1px; background: var(--line); }
.sub-label::before { content: ''; width: 8px; height: 8px; background: var(--hue, var(--accent)); }

/* ── concept cards (the homogenized interactive card) ── */
.ccards { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 14px; margin: 18px 0 26px; }
.ccard {
  --ch: var(--hue-a);
  position: relative; background: var(--paper-2); border: 1px solid var(--line);
  border-left: 3px solid var(--ch); padding: 20px 20px 16px;
  transition: transform .35s var(--ease), box-shadow .35s var(--ease), background .3s;
  overflow: hidden;
}
.ccard:nth-child(4n+2) { --ch: var(--hue-b); }
.ccard:nth-child(4n+3) { --ch: var(--hue-c); }
.ccard:nth-child(4n+4) { --ch: var(--hue-d); }
.ccard:hover { transform: translateY(-4px); box-shadow: 0 16px 34px -16px rgba(14,14,12,.25); background: var(--paper); }
.ccard-badge {
  display: inline-block; font-family: var(--mono); font-size: 9px; font-weight: 600;
  letter-spacing: .16em; text-transform: uppercase; color: var(--ch);
  padding: 3px 9px; border: 1px solid color-mix(in srgb, var(--ch) 45%, transparent);
  border-radius: 100px; margin-bottom: 10px; background: color-mix(in srgb, var(--ch) 7%, transparent);
}
.ccard h4 { font-family: var(--display); font-weight: 700; font-size: 16.5px; line-height: 1.25; letter-spacing: -.012em; margin-bottom: 8px; }
.ccard-body { font-size: 13.2px; line-height: 1.62; color: var(--ink-2); }
.ccard-body strong, .ccard-body b { color: var(--ink); }
.ccard-body em { color: var(--ch); font-style: italic; }
.ccard-body a { color: var(--ch); text-decoration: underline; text-underline-offset: 2px; }
/* collapsible long cards */
.ccard.clip .ccard-body { max-height: 116px; overflow: hidden; position: relative; }
.ccard.clip .ccard-body::after {
  content: ''; position: absolute; left: 0; right: 0; bottom: 0; height: 48px;
  background: linear-gradient(transparent, var(--paper-2));
}
.ccard.clip:hover .ccard-body::after { background: linear-gradient(transparent, var(--paper)); }
.ccard.open .ccard-body { max-height: none; }
.ccard.open .ccard-body::after { display: none; }
.ccard-more {
  margin-top: 10px; font-family: var(--mono); font-size: 10px; letter-spacing: .12em;
  text-transform: uppercase; color: var(--ch); display: inline-flex; align-items: center; gap: 6px;
}
.ccard-more .pm { display: inline-grid; place-items: center; width: 16px; height: 16px; border: 1px solid var(--ch); border-radius: 50%; font-size: 11px; line-height: 1; transition: transform .3s var(--ease-3); }
.ccard.open .ccard-more .pm { transform: rotate(45deg); }

/* ── animated flow rail ── */
.flow-rail { margin: 22px 0 28px; border: 1px solid var(--line); background: var(--paper-2); padding: 22px 20px 18px; overflow-x: auto; }
.flow-rail-inner { display: flex; align-items: stretch; gap: 0; min-width: min-content; }
.fnode {
  position: relative; flex-shrink: 0;
  font-family: var(--mono); font-size: 11.5px; font-weight: 500; line-height: 1.4;
  padding: 12px 16px; border: 1px solid var(--line-2); background: var(--paper);
  max-width: 200px; min-width: 110px; text-align: center; display: flex; align-items: center; justify-content: center;
  transition: all .35s var(--ease);
}
.fnode.lit { border-color: var(--hue, var(--accent)); background: var(--accent-soft); color: var(--ink); box-shadow: 0 6px 18px -8px rgba(255,77,0,.4); }
.fjoin { flex-shrink: 0; width: 34px; display: grid; place-items: center; color: var(--ink-3); position: relative; }
.fjoin::before { content: ''; position: absolute; left: 0; right: 0; top: 50%; height: 1.5px; background: var(--line-2); }
.fjoin svg { position: relative; z-index: 1; background: var(--paper-2); }
.fjoin .tip { fill: var(--ink-3); transition: fill .3s; }
.fjoin.lit::before { background: var(--hue, var(--accent)); }
.fjoin.lit .tip { fill: var(--hue, var(--accent)); }
.flow-cap { margin-top: 12px; font-family: var(--mono); font-size: 9.5px; letter-spacing: .12em; text-transform: uppercase; color: var(--ink-3); display: flex; justify-content: space-between; }
.flow-cap button { color: var(--accent); letter-spacing: .12em; text-transform: uppercase; font-size: 9.5px; font-family: var(--mono); }
.flow-cap button:hover { text-decoration: underline; }

/* ── stats strip ── */
.stat-strip { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); margin: 22px 0 28px; }
.sstat { background: var(--paper-2); padding: 20px 18px; transition: background .3s; }
.sstat:hover { background: var(--paper); }
.sstat .v { font-family: var(--display); font-weight: 800; font-size: 30px; letter-spacing: -.02em; color: var(--ink); }
.sstat .v .unit { font-size: 16px; color: var(--hue, var(--accent)); font-weight: 600; }
.sstat .k { margin-top: 4px; font-size: 11.5px; line-height: 1.45; color: var(--ink-2); }

/* ── list block ── */
.nice-list { margin: 14px 0 22px; display: flex; flex-direction: column; gap: 9px; max-width: 75ch; }
.nice-list li {
  position: relative; padding: 11px 16px 11px 38px; font-size: 13.5px; color: var(--ink-2);
  background: var(--paper-2); border: 1px solid var(--line);
  transition: transform .3s var(--ease), background .3s;
}
.nice-list li:hover { transform: translateX(4px); background: var(--paper); }
.nice-list li::before {
  content: '→'; position: absolute; left: 14px; top: 10px; color: var(--hue, var(--accent));
  font-family: var(--mono); font-size: 12px;
}
.nice-list li strong { color: var(--ink); }

/* ── then vs now strip ── */
.nownote {
  display: grid; grid-template-columns: 1fr auto 1fr; gap: 0;
  margin: 22px 0 28px; border: 1px solid var(--line-2); overflow: hidden;
}
.nownote .nn-col { padding: 18px 20px; }
.nownote .then { background: var(--paper-3); }
.nownote .then .nn-v { color: var(--ink-2); }
.nownote .now { background: var(--paper); border-left: 3px solid var(--hue, var(--accent)); }
.nownote .nn-l {
  font-family: var(--mono); font-size: 9.5px; font-weight: 600; letter-spacing: .16em;
  text-transform: uppercase; color: var(--ink-3); margin-bottom: 8px;
}
.nownote .now .nn-l { color: var(--hue, var(--accent)); }
.nownote .nn-v { font-size: 13px; line-height: 1.6; }
.nownote .nn-v strong { color: var(--ink); }
.nownote .nn-v em { color: var(--hue, var(--accent)); }
.nownote .nn-arrow {
  display: grid; place-items: center; padding: 0 6px;
  background: var(--paper-2); color: var(--hue, var(--accent));
}
.nownote .nn-arrow svg { animation: nn-nudge 2.2s ease-in-out infinite; }
@keyframes nn-nudge { 0%,100% { transform: translateX(0); } 50% { transform: translateX(5px); } }
@media (max-width: 700px) {
  .nownote { grid-template-columns: 1fr; }
  .nownote .nn-arrow { padding: 6px 0; }
  .nownote .nn-arrow svg { transform: rotate(90deg); animation: none; }
  .nownote .now { border-left: 0; border-top: 3px solid var(--hue, var(--accent)); }
}

/* ── papers / further reading ── */
.papers { display: flex; flex-direction: column; gap: 10px; margin: 16px 0 10px; }
.paper-chip {
  display: flex; align-items: center; gap: 14px; padding: 14px 18px;
  border: 1px solid var(--line); background: var(--paper-2);
  transition: border-color .3s, transform .3s var(--ease), background .3s;
}
.paper-chip:hover { border-color: var(--accent); transform: translateX(5px); background: var(--paper); }
.paper-chip .pic { font-family: var(--mono); font-size: 13px; color: var(--accent); }
.paper-chip .t { font-size: 13.5px; font-weight: 600; color: var(--ink); }
.paper-chip .n { font-size: 11.5px; color: var(--ink-3); font-style: italic; }
.paper-chip .ext { margin-left: auto; font-family: var(--mono); font-size: 11px; color: var(--ink-3); }

/* ── playground bezel ── */
.playground { margin: 26px 0; border: 1px solid var(--line-2); background: var(--dark); border-radius: 4px; overflow: hidden; }
.pg-head {
  display: flex; align-items: center; gap: 12px; padding: 12px 18px;
  background: var(--dark-2); border-bottom: 1px solid rgba(235,231,221,.08);
}
.pg-dots { display: flex; gap: 5px; }
.pg-dots i { width: 9px; height: 9px; border-radius: 50%; background: rgba(235,231,221,.16); }
.pg-dots i:first-child { background: var(--accent); }
.pg-head .t { font-family: var(--mono); font-size: 10.5px; letter-spacing: .14em; text-transform: uppercase; color: rgba(235,231,221,.7); }
.pg-head .open { margin-left: auto; font-family: var(--mono); font-size: 10px; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); }
.pg-head .open:hover { text-decoration: underline; }
.playground iframe { width: 100%; height: 560px; border: 0; display: block; background: var(--dark); }

/* ── spotlight figure ── */
.spotlight { margin: 34px 0; }

/* ── audio player ── */
.audio-player {
  position: sticky; top: 76px; z-index: 240;
  display: flex; align-items: center; gap: 14px;
  max-width: 1000px; margin: 0 auto; padding: 10px 16px;
  background: rgba(20,19,15,.94); color: var(--paper); border-radius: 100px;
  backdrop-filter: blur(10px); box-shadow: 0 14px 34px -14px rgba(14,14,12,.5);
  width: calc(100% - var(--pad-x) * 2);
}
.ap-play {
  width: 38px; height: 38px; border-radius: 50%; background: var(--accent); color: #fff;
  display: grid; place-items: center; flex-shrink: 0; transition: transform .25s var(--ease-3), background .25s;
}
.ap-play:hover { transform: scale(1.08); }
.audio-player .ic-pause { display: none; }
.audio-player.playing .ic-pause { display: block; }
.audio-player.playing .ic-play { display: none; }
.ap-meta { min-width: 0; }
.ap-meta .l { font-family: var(--mono); font-size: 9px; letter-spacing: .14em; text-transform: uppercase; color: rgba(235,231,221,.55); }
.ap-meta .v { font-size: 12.5px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.ap-progress { flex: 1; height: 22px; display: flex; align-items: center; cursor: pointer; position: relative; }
.ap-progress .rail { width: 100%; height: 3px; background: rgba(235,231,221,.18); border-radius: 2px; overflow: hidden; }
.ap-progress .fill { height: 100%; width: 0%; background: var(--accent); border-radius: 2px; }
.ap-time { font-family: var(--mono); font-size: 10px; color: rgba(235,231,221,.6); white-space: nowrap; }
.ap-wave { display: flex; align-items: center; gap: 2px; height: 16px; }
.ap-wave i { width: 2.5px; background: var(--accent); height: 4px; border-radius: 2px; transition: height .15s; }
.audio-player.playing .ap-wave i { animation: wave .9s ease-in-out infinite; }
.audio-player.playing .ap-wave i:nth-child(2) { animation-delay: .15s; }
.audio-player.playing .ap-wave i:nth-child(3) { animation-delay: .3s; }
.audio-player.playing .ap-wave i:nth-child(4) { animation-delay: .45s; }
@keyframes wave { 0%,100% { height: 4px; } 50% { height: 14px; } }
@media (max-width: 700px) { .ap-time, .ap-wave { display: none; } }

/* ── takeaway / complete strip ── */
.complete-strip {
  display: flex; align-items: center; gap: 18px; flex-wrap: wrap;
  margin: 46px 0 0; padding: 26px; border: 1px dashed var(--line-2); background: var(--paper-2);
}
.complete-strip .txt { flex: 1; min-width: 220px; }
.complete-strip .txt .t { font-family: var(--display); font-weight: 800; font-size: 20px; letter-spacing: -.015em; }
.complete-strip .txt .s { font-size: 13px; color: var(--ink-2); margin-top: 3px; }
.btn-complete {
  font-family: var(--mono); font-size: 11px; letter-spacing: .12em; text-transform: uppercase;
  padding: 14px 24px; background: var(--ink); color: var(--paper); border-radius: 2px;
  display: inline-flex; gap: 10px; align-items: center;
  transition: background .3s, transform .3s var(--ease);
}
.btn-complete:hover { background: var(--accent); transform: translateY(-2px); }
.btn-complete.done { background: var(--ok); }

/* ── pager ── */
.lesson-pager {
  max-width: 1000px; margin: 0 auto; padding: 26px var(--pad-x) 40px;
  display: grid; grid-template-columns: 1fr 1fr; gap: 14px;
}
.lesson-pager a {
  border: 1px solid var(--line); background: var(--paper-2); padding: 20px 22px;
  transition: border-color .3s, transform .35s var(--ease), background .3s;
}
.lesson-pager a:hover { border-color: var(--accent); transform: translateY(-3px); background: var(--paper); }
.lesson-pager a.next { text-align: right; }
.lesson-pager .l { font-family: var(--mono); font-size: 9.5px; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); margin-bottom: 6px; }
.lesson-pager .v { font-family: var(--display); font-weight: 700; font-size: 16px; letter-spacing: -.01em; }
.lesson-pager a.spacer { visibility: hidden; }

/* ════════════════ FOOTER ════════════════ */
footer {
  border-top: 1px solid var(--line-2); margin-top: 30px;
  display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap;
  padding: 26px var(--pad-x); max-width: var(--max-w); margin-left: auto; margin-right: auto;
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .1em; text-transform: uppercase; color: var(--ink-3);
}
footer a:hover { color: var(--accent); }

/* ── mobile fixes: filter bar unsticks + scrolls; map hidden; pager stacks ── */
@media (max-width: 700px) {
  .filterbar {
    position: static;
    flex-wrap: nowrap; overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
    padding-bottom: 12px;
  }
  .fchip { flex: 0 0 auto; }
  .fsearch { flex: 0 0 auto; min-width: 170px; margin-left: 4px; }
  .map-wrap { display: none; }
  .lesson-pager { grid-template-columns: 1fr; }
  .lesson-pager a.spacer { display: none; }
}

/* level intro strip on lesson pages */
.context-strip {
  display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 26px;
  font-family: var(--mono); font-size: 10.5px; letter-spacing: .08em; color: var(--ink-3); text-transform: uppercase;
}
.context-strip .sep { color: var(--ink-4); }
.context-strip a { color: var(--ink-2); border-bottom: 1px dashed var(--line-2); padding-bottom: 1px; }
.context-strip a:hover { color: var(--accent); border-color: var(--accent); }