/* Terminal Velocity — design tokens & components.
   Warm charcoal base, ANSI-family accents, mono display type.
   Signature: progress rendered as file permissions. */

:root {
  /* surfaces — warm charcoal, not neutral black */
  --bg: #131110;
  --bg-deep: #0d0b0a;
  --panel: #1b1815;
  --panel-2: #232019;
  --line: #2e2a24;
  --line-strong: #3d372e;

  /* ink */
  --fg: #e8e3d8;
  --fg-dim: #a89f90;
  --fg-faint: #8d8477;  /* AA on --bg-deep — the faint tier must still be READABLE */

  /* the ANSI family, recalibrated for warm dark */
  --ansi-green: #a9cc66;
  --ansi-green-dim: #5c7433;
  --ansi-yellow: #e5b567;
  --ansi-red: #e2705e;
  --ansi-blue: #7ba5dd;
  --ansi-magenta: #c792c7;
  --ansi-cyan: #7fbfb5;

  --accent: var(--ansi-green);
  --xp: var(--ansi-yellow);

  --font-mono: 'IBM Plex Mono', ui-monospace, 'JetBrains Mono', 'Cascadia Code', Menlo, monospace;
  --font-sans: 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;

  --radius: 8px;
  --radius-lg: 14px;
  --shadow: 0 8px 32px rgba(0, 0, 0, .45);
  --maxw: 1080px;
  --prose: 46rem;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001s !important;
    transition-duration: .001s !important;
    /* speeding up an INFINITE animation does not stop it — it runs it 1000x
       faster. The blink went to ~20 flashes a second, which is worse than
       leaving it alone and is a seizure risk. Stop them outright. */
    animation-iteration-count: 1 !important;
  }
  .cursor-blink, .perm-dot { animation: none !important; opacity: 1 !important; }
}

/* Visible only to screen readers — used for the Tab-escape hint. */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

/* A2: these controls are deliberately borderless, but "no outline, ever" means
   a keyboard user cannot see where they are. Restore it for keyboard focus
   only, so mouse users see nothing change. */
.term-input:focus-visible,
.pypad-code:focus-visible,
.codex-filter:focus-visible {
  outline: 2px solid var(--ansi-cyan);
  outline-offset: -2px;
  border-radius: 4px;
}

/* A4: quiz results were conveyed by colour alone — a red/green colour-blind
   learner could not tell which answer was right. The site already uses ✓/✗
   everywhere else; use them here too. */
.quiz-choice.correct::after { content: ' ✓'; font-weight: 700; }
.quiz-choice.wrong::after { content: ' ✗'; font-weight: 700; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 16.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* faint phosphor grain */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: .035;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='120' height='120' filter='url(%23n)'/%3E%3C/svg%3E");
}

#app { position: relative; z-index: 1; }

a { color: var(--ansi-cyan); text-decoration: none; }
a:hover { text-decoration: underline; }

code, pre, kbd { font-family: var(--font-mono); }
code {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: .1em .35em;
  font-size: .88em;
  color: var(--ansi-yellow);
  white-space: nowrap;
}
pre code { background: none; border: none; padding: 0; color: inherit; white-space: pre; }
kbd {
  background: var(--panel-2);
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 5px;
  padding: .08em .45em;
  font-size: .82em;
}

::selection { background: rgba(169, 204, 102, .25); }

:focus-visible { outline: 2px solid var(--ansi-cyan); outline-offset: 2px; border-radius: 3px; }

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

/* ---------- top bar ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  padding: .65rem 1.25rem;
  background: color-mix(in srgb, var(--bg-deep) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: .95rem;
  color: var(--fg);
  letter-spacing: -.02em;
  white-space: nowrap;
}
.brand .caret { color: var(--accent); }
.brand .tld { color: var(--fg-faint); font-weight: 400; }
.topbar nav { display: flex; gap: .25rem; margin-left: .5rem; }
.topbar nav a {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--fg-dim);
  padding: .35rem .7rem;
  border-radius: 6px;
}
.topbar nav a:hover { color: var(--fg); background: var(--panel); text-decoration: none; }
.topbar nav a.active { color: var(--accent); background: var(--panel); }
.topbar nav a .slash { color: var(--fg-faint); }

/* ---------- nav dropdowns (fifteen flat links was a wall) ---------- */
.navgroup { position: relative; }
.navgroup-btn {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--fg-dim);
  background: none;
  border: 0;
  padding: .35rem .7rem;
  border-radius: 6px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: .35rem;
}
.navgroup-btn:hover { color: var(--fg); background: var(--panel); }
.navgroup-btn.active { color: var(--accent); background: var(--panel); }
.navgroup-btn .chev { font-size: .6rem; color: var(--fg-faint); transition: transform .15s ease; }
.navgroup.open .navgroup-btn { color: var(--fg); background: var(--panel); }
.navgroup.open .navgroup-btn .chev { transform: rotate(180deg); }
.navgroup-panel {
  display: none;
  position: absolute;
  top: calc(100% + .45rem);
  left: 0;
  min-width: 15rem;
  padding: .5rem;
  background: var(--panel);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  z-index: 60;
}
.navgroup.open .navgroup-panel { display: block; }
/* the right-hand group opens leftwards so it never runs off the viewport */
.navgroup:last-child .navgroup-panel { left: auto; right: 0; }
@media (max-width: 720px) {
  .navgroup-panel { min-width: 0; width: max-content; max-width: calc(100vw - 1.6rem); }
  .navgroup-panel .ng-hint { display: none; }
}
.navgroup-sec + .navgroup-sec { margin-top: .45rem; padding-top: .45rem; border-top: 1px solid var(--line); }
.navgroup-label {
  display: block;
  font-family: var(--font-mono);
  font-size: .68rem;
  color: var(--fg-faint);
  padding: .15rem .5rem .3rem;
}
.navgroup-panel a {
  display: flex;
  align-items: baseline;
  gap: .6rem;
  padding: .32rem .5rem;
  border-radius: 5px;
  font-family: var(--font-mono);
  font-size: .82rem;
  color: var(--fg-dim);
}
.navgroup-panel a:hover { background: var(--panel-2); color: var(--fg); text-decoration: none; }
.navgroup-panel a.active { color: var(--accent); background: var(--panel-2); }
.navgroup-panel .ng-name { flex: 1; }
.navgroup-panel .ng-pct { font-size: .7rem; color: var(--fg-faint); }
.navgroup-panel .ng-pct.done { color: var(--accent); }
.navgroup-panel .ng-hint { font-size: .68rem; color: var(--fg-faint); max-width: 9rem; text-align: right; }

.topbar .stats {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: .8rem;
}
.stat-xp { color: var(--xp); }
.stat-streak { color: var(--ansi-red); }
.stat-level { color: var(--fg-dim); }
.stat-level b { color: var(--fg); font-weight: 600; }

/* xp pop animation in topbar */
@keyframes xp-pop {
  0% { transform: translateY(0); opacity: 0; }
  20% { transform: translateY(-4px); opacity: 1; }
  80% { transform: translateY(-14px); opacity: 1; }
  100% { transform: translateY(-22px); opacity: 0; }
}
.xp-float {
  position: absolute;
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--xp);
  pointer-events: none;
  animation: xp-pop 1.1s ease-out forwards;
  z-index: 90;
}

/* ---------- layout ---------- */
.page { max-width: var(--maxw); margin: 0 auto; padding: 2.5rem 1.25rem 6rem; }
.page-narrow { max-width: var(--prose); margin: 0 auto; padding: 2.5rem 1.25rem 6rem; }

.eyebrow {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--fg-faint);
  margin: 0 0 .6rem;
}
.eyebrow .num { color: var(--accent); text-transform: none; letter-spacing: .04em; }

h1, h2, h3 { font-family: var(--font-mono); letter-spacing: -.02em; line-height: 1.2; }
h1 { font-size: clamp(1.9rem, 4.5vw, 3rem); font-weight: 700; margin: 0 0 1rem; }
h2 { font-size: 1.35rem; font-weight: 600; margin: 2.8rem 0 .8rem; }
h3 { font-size: 1.05rem; font-weight: 600; margin: 2rem 0 .6rem; }

.lede { font-size: 1.1rem; color: var(--fg-dim); max-width: 38rem; }

/* ---------- hero terminal ---------- */
.hero {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
  gap: 3rem;
  align-items: center;
  padding: 3.5rem 0 3rem;
}
@media (max-width: 900px) { .hero { grid-template-columns: 1fr; padding-top: 1.5rem; } }

.hero h1 .accent { color: var(--accent); }
.hero h1 .cursor-blink {
  display: inline-block;
  width: .55em; height: 1.05em;
  background: var(--accent);
  vertical-align: text-bottom;
  margin-left: .08em;
  animation: blink 1.1s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  font-family: var(--font-mono);
  font-size: .88rem;
  font-weight: 600;
  padding: .7rem 1.3rem;
  border-radius: var(--radius);
  background: var(--accent);
  color: #17190e;
  transition: transform .12s ease, box-shadow .12s ease;
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 6px 20px rgba(169, 204, 102, .25); text-decoration: none; }
.btn:active { transform: translateY(0); }
.btn-ghost {
  background: transparent;
  color: var(--fg-dim);
  border: 1px solid var(--line-strong);
}
.btn-ghost:hover { color: var(--fg); box-shadow: none; }

/* ---------- terminal component ---------- */
.term {
  background: var(--bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: .85rem;
  line-height: 1.5;
}
.term-head {
  display: flex;
  align-items: center;
  gap: .5rem;
  padding: .55rem .9rem;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  user-select: none;
}
.term-dots { display: flex; gap: .38rem; }
.term-dots span { width: 11px; height: 11px; border-radius: 50%; background: var(--line-strong); }
.term-dots span:nth-child(1) { background: #b3564c; }
.term-dots span:nth-child(2) { background: #b99b4e; }
.term-dots span:nth-child(3) { background: #6f8f47; }
.term-title {
  flex: 1;
  text-align: center;
  font-size: .72rem;
  color: var(--fg-faint);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.term-actions { display: flex; gap: .35rem; }
.term-actions button {
  font-family: var(--font-mono);
  font-size: .68rem;
  color: var(--fg-faint);
  padding: .15rem .55rem;
  border: 1px solid var(--line);
  border-radius: 5px;
}
.term-actions button:hover { color: var(--fg); border-color: var(--line-strong); }

.term-screen {
  padding: .85rem 1rem;
  height: 340px;
  overflow-y: auto;
  overscroll-behavior: contain;
  cursor: text;
  scrollbar-width: thin;
  scrollbar-color: var(--line-strong) transparent;
}
.term-screen .line { white-space: pre-wrap; word-break: break-word; min-height: 1.28em; }

.term-input-row { display: flex; align-items: baseline; }
.term-prompt { white-space: pre; }
.term-prompt .u { color: var(--ansi-green); }
.term-prompt .p { color: var(--ansi-blue); }
.term-input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  color: var(--fg);
  font: inherit;
  padding: 0;
  margin: 0;
  caret-color: var(--accent);
  min-width: 2ch;
}

/* ANSI color spans */
.a-red { color: var(--ansi-red); } .a-green { color: var(--ansi-green); }
.a-yellow { color: var(--ansi-yellow); } .a-blue { color: var(--ansi-blue); }
.a-magenta { color: var(--ansi-magenta); } .a-cyan { color: var(--ansi-cyan); }
.a-bold { font-weight: 700; } .a-dim { color: var(--fg-faint); }

/* ---------- course map: ls -l listing ---------- */
.arc {
  margin: 2.5rem 0 0;
}
.arc-head {
  display: flex;
  align-items: baseline;
  gap: .9rem;
  font-family: var(--font-mono);
  border-bottom: 1px solid var(--line);
  padding-bottom: .55rem;
  margin-bottom: .4rem;
}
.arc-head .triad { color: var(--fg-faint); font-size: .78rem; letter-spacing: .1em; }
.arc-head h2 { margin: 0; font-size: 1.05rem; }
.arc-head .arc-desc { color: var(--fg-dim); font-size: .8rem; margin-left: auto; font-family: var(--font-sans); }

.mod-row {
  display: grid;
  grid-template-columns: 11ch 3.2rem minmax(0, 1fr) auto;
  gap: 1.1rem;
  align-items: center;
  padding: .72rem .8rem;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  color: inherit;
  transition: background .12s ease;
}
a.mod-row:hover { background: var(--panel); text-decoration: none; }
.mod-perms {
  font-size: .82rem;
  letter-spacing: 0;       /* real ls -l density — the signature must read as a mode string */
  color: var(--fg-dim);
  white-space: pre;
}
.mod-perms .on { color: var(--ansi-green); }
.mod-perms .partial { color: var(--ansi-yellow); }
.mod-num {
  font-size: .78rem;
  color: var(--fg-faint);
  text-align: right;
}
.mod-name { display: flex; flex-direction: column; gap: .1rem; min-width: 0; }
.mod-name .t { font-weight: 600; font-size: .95rem; }
.mod-name .s { font-family: var(--font-sans); font-size: .8rem; color: var(--fg-dim); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.mod-meta { font-size: .75rem; color: var(--fg-faint); display: flex; align-items: center; gap: .8rem; }
.mod-meta .done { color: var(--ansi-green); }
.mod-row.locked { opacity: .55; }
.mod-row.locked .t::after { content: '  🔒'; font-size: .8em; }
@media (max-width: 720px) {
  .mod-row { grid-template-columns: auto minmax(0, 1fr); grid-template-areas: 'perms name' 'perms meta'; row-gap: .15rem; }
  .mod-perms { grid-area: perms; font-size: .7rem; align-self: center; }
  .mod-num { display: none; }
  .mod-name { grid-area: name; }
  .mod-name .s { white-space: normal; }
  .mod-meta { grid-area: meta; }
}

/* progress ring (course card) */
.ring { transform: rotate(-90deg); }
.ring .track { stroke: var(--line); }
.ring .fill { stroke: var(--accent); stroke-linecap: round; transition: stroke-dashoffset .6s ease; }

/* ---------- course cards on dashboard ---------- */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.2rem;
  margin-top: 1.5rem;
}
.course-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: .6rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.4rem;
  color: inherit;
  overflow: hidden;
  transition: border-color .15s ease, transform .15s ease;
}
a.course-card:hover { border-color: var(--line-strong); transform: translateY(-2px); text-decoration: none; }
.course-card .cmd { font-family: var(--font-mono); font-size: .78rem; color: var(--fg-faint); }
.course-card .cmd b { color: var(--accent); font-weight: 500; }
.course-card h3 { margin: 0; font-size: 1.25rem; }
.course-card p { margin: 0; color: var(--fg-dim); font-size: .9rem; }
.course-card .foot {
  margin-top: auto;
  padding-top: .8rem;
  display: flex;
  align-items: center;
  gap: .8rem;
  font-family: var(--font-mono);
  font-size: .75rem;
  color: var(--fg-faint);
}
.course-card.soon { opacity: .6; }
.course-card.soon .badge-soon {
  font-family: var(--font-mono); font-size: .68rem; color: var(--ansi-yellow);
  border: 1px solid color-mix(in srgb, var(--ansi-yellow) 40%, transparent);
  padding: .1rem .5rem; border-radius: 99px;
}

/* ---------- lesson page ---------- */
.lesson-head { margin-bottom: 2rem; }
.crumbs {
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--fg-faint);
  margin-bottom: 1.2rem;
}
.crumbs a { color: var(--fg-dim); }
.crumbs .sep { margin: 0 .4rem; color: var(--fg-faint); }

.lesson-body h2 {
  font-size: 1.25rem;
  padding-top: 1rem;
}
.lesson-body h2::before { content: '## '; color: var(--fg-faint); font-weight: 400; }
.lesson-body p { max-width: var(--prose); }
.lesson-body ul, .lesson-body ol { max-width: var(--prose); padding-left: 1.4rem; }
.lesson-body li { margin: .3rem 0; }

pre.shell {
  background: var(--bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: .9rem 1.1rem;
  overflow-x: auto;
  font-size: .84rem;
  line-height: 1.55;
  max-width: var(--prose);
}
pre.shell .p { color: var(--ansi-green); user-select: none; }
pre.shell .o { color: var(--fg-dim); }
pre.shell .c { color: var(--fg-faint); font-style: italic; }

/* callouts */
.callout {
  max-width: var(--prose);
  border: 1px solid var(--line);
  border-left: 3px solid var(--ansi-cyan);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: var(--panel);
  padding: .9rem 1.1rem;
  margin: 1.4rem 0;
  font-size: .92rem;
}
.callout .co-label {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  display: block;
  margin-bottom: .35rem;
}
.callout-tip { border-left-color: var(--ansi-cyan); }
.callout-tip .co-label { color: var(--ansi-cyan); }
.callout-warn { border-left-color: var(--ansi-red); }
.callout-warn .co-label { color: var(--ansi-red); }
.callout-deep { border-left-color: var(--ansi-magenta); }
.callout-deep .co-label { color: var(--ansi-magenta); }
.callout p { margin: .3rem 0; }
.callout :last-child { margin-bottom: 0; }

/* exercise card */
.exercise {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--panel);
  margin: 2.2rem 0;
  overflow: hidden;
}
.exercise.done { border-color: color-mix(in srgb, var(--ansi-green) 45%, var(--line-strong)); }
.ex-head {
  display: flex;
  align-items: center;
  gap: .8rem;
  padding: .9rem 1.2rem;
  border-bottom: 1px solid var(--line);
}
.ex-badge {
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .12em;
  color: var(--bg-deep);
  background: var(--ansi-yellow);
  padding: .18rem .55rem;
  border-radius: 4px;
  font-weight: 700;
}
.exercise.done .ex-badge { background: var(--ansi-green); }
.ex-head h3 { margin: 0; font-size: .98rem; flex: 1; }
.ex-xp { font-family: var(--font-mono); font-size: .78rem; color: var(--xp); }
.exercise.done .ex-xp { color: var(--ansi-green); }
.ex-task pre.shell { margin: .4rem 0 .9rem; } /* transcript blocks embedded in task text */
.ex-task { padding: 1rem 1.2rem .4rem; font-size: .95rem; }
.ex-task p { margin: .3rem 0 .8rem; }
.ex-body { padding: 0 1.2rem 1.2rem; }
.ex-foot {
  display: flex;
  align-items: center;
  gap: .8rem;
  padding: .7rem 1.2rem;
  border-top: 1px solid var(--line);
  font-size: .82rem;
}
.ex-foot .hint-btn, .ex-foot .solution-btn {
  font-family: var(--font-mono);
  font-size: .75rem;
  color: var(--fg-dim);
  border: 1px solid var(--line);
  padding: .3rem .7rem;
  border-radius: 6px;
}
.ex-foot .hint-btn:hover, .ex-foot .solution-btn:hover { color: var(--fg); border-color: var(--line-strong); }
.ex-status { margin-left: auto; font-family: var(--font-mono); font-size: .78rem; color: var(--fg-faint); }
.exercise.done .ex-status { color: var(--ansi-green); }
.ex-hint {
  margin: .6rem 1.2rem 1rem;
  padding: .7rem 1rem;
  background: var(--bg-deep);
  border-radius: var(--radius);
  border: 1px dashed var(--line-strong);
  font-size: .88rem;
  color: var(--fg-dim);
}
.ex-hint code { white-space: pre-wrap; }

@keyframes ex-success-flash {
  0% { box-shadow: 0 0 0 0 rgba(169, 204, 102, .0); }
  30% { box-shadow: 0 0 0 4px rgba(169, 204, 102, .35); }
  100% { box-shadow: 0 0 0 0 rgba(169, 204, 102, 0); }
}
.exercise.flash { animation: ex-success-flash .9s ease-out; }

/* quiz */
.quiz {
  max-width: var(--prose);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--panel);
  padding: 1.2rem 1.4rem;
  margin: 2.2rem 0;
}
.quiz .q { font-weight: 600; margin: 0 0 .9rem; }
.quiz .q::before {
  content: '?';
  font-family: var(--font-mono);
  color: var(--ansi-magenta);
  font-weight: 700;
  margin-right: .6rem;
}
.quiz-choice {
  display: block;
  width: 100%;
  text-align: left;
  font-size: .92rem;
  padding: .55rem .9rem;
  margin: .35rem 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color .12s ease, background .12s ease;
}
.quiz-choice:hover { border-color: var(--line-strong); background: var(--panel-2); }
.quiz-choice.correct { border-color: var(--ansi-green); color: var(--ansi-green); background: color-mix(in srgb, var(--ansi-green) 8%, transparent); }
.quiz-choice.wrong { border-color: var(--ansi-red); color: var(--ansi-red); }
.quiz-choice:disabled { cursor: default; }
.quiz-explain {
  margin-top: .8rem;
  font-size: .88rem;
  color: var(--fg-dim);
  border-top: 1px dashed var(--line);
  padding-top: .8rem;
}
.quiz-explain::before { content: '→ '; color: var(--ansi-green); }

/* lesson nav */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3.5rem;
  border-top: 1px solid var(--line);
  padding-top: 1.5rem;
}
.lesson-nav a {
  font-family: var(--font-mono);
  font-size: .85rem;
  color: var(--fg-dim);
  max-width: 45%;
}
.lesson-nav a:hover { color: var(--fg); }
.lesson-nav .next { margin-left: auto; text-align: right; color: var(--accent); }

/* lesson list inside module page */
.lesson-row {
  display: flex;
  align-items: center;
  gap: .9rem;
  padding: .65rem .8rem;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: .9rem;
  color: inherit;
}
a.lesson-row:hover { background: var(--panel); text-decoration: none; }
.lesson-row .st { width: 1.2rem; color: var(--fg-faint); }
.lesson-row .st.done { color: var(--ansi-green); }
.lesson-row .xp-tag { margin-left: auto; font-size: .72rem; color: var(--fg-faint); }

/* ---------- badges ---------- */
.badge-shelf {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: .8rem;
  margin-top: 1rem;
}
.badge {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  padding: .8rem;
  text-align: center;
  font-size: .78rem;
  color: var(--fg-dim);
}
.badge .icon { font-size: 1.6rem; display: block; margin-bottom: .3rem; }
.badge.locked { opacity: .35; filter: grayscale(1); }
.badge .bt { font-family: var(--font-mono); font-weight: 600; color: var(--fg); display: block; font-size: .78rem; }

/* ---------- confetti ---------- */
.confetti-piece {
  position: fixed;
  font-family: var(--font-mono);
  font-size: 14px;
  pointer-events: none;
  z-index: 100;
  animation: confetti-fall linear forwards;
}
@keyframes confetti-fall {
  to { transform: translateY(105vh) rotate(720deg); opacity: .1; }
}

/* ---------- toast ---------- */
.toast {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--panel-2);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: .7rem 1.2rem;
  font-family: var(--font-mono);
  font-size: .85rem;
  z-index: 95;
  box-shadow: var(--shadow);
  animation: toast-in .25s ease-out;
}
@keyframes toast-in { from { transform: translate(-50%, 12px); opacity: 0; } }
.toast .icon { margin-right: .5rem; }

/* ---------- reference page ---------- */
.ref-grid { columns: 3 240px; column-gap: 1.5rem; margin-top: 1.5rem; }
.ref-cat { break-inside: avoid; margin-bottom: 1.6rem; }
.ref-cat h3 { margin: 0 0 .5rem; font-size: .85rem; color: var(--ansi-yellow); }
.ref-cat a {
  display: flex;
  gap: .7rem;
  font-family: var(--font-mono);
  font-size: .82rem;
  padding: .18rem .4rem;
  border-radius: 5px;
  color: var(--fg);
}
.ref-cat a:hover { background: var(--panel); text-decoration: none; }
.ref-cat a .sum { color: var(--fg-faint); font-family: var(--font-sans); font-size: .78rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* man page view */
.man-view {
  background: var(--bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.5rem 1.8rem;
  font-family: var(--font-mono);
  font-size: .85rem;
  line-height: 1.6;
  white-space: pre-wrap;
  margin-top: 1.5rem;
}

/* ---------- footer ---------- */
.foot-note {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: .75rem;
  color: var(--fg-faint);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: .5rem;
}

/* level-up modal */
.levelup-overlay {
  position: fixed; inset: 0; z-index: 98;
  background: rgba(13, 11, 10, .8);
  backdrop-filter: blur(4px);
  display: grid; place-items: center;
  animation: toast-in .3s ease-out;
}
.levelup {
  background: var(--panel);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  padding: 2.2rem 3rem;
  text-align: center;
  font-family: var(--font-mono);
  box-shadow: var(--shadow);
}
.levelup .lvl-num { font-size: .8rem; color: var(--fg-faint); letter-spacing: .15em; }
.levelup .lvl-name { font-size: 1.8rem; font-weight: 700; color: var(--accent); margin: .5rem 0 1rem; }
.levelup button { margin-top: .5rem; }

/* ---------- PyPad (python editor) ---------- */
.pypad {
  background: var(--bg-deep);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: .86rem;
}
.pypad-head {
  display: flex;
  align-items: center;
  gap: .5rem;
  padding: .55rem .9rem;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  user-select: none;
}
.pypad-title {
  flex: 1;
  text-align: center;
  font-size: .72rem;
  color: var(--fg-faint);
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}
.pypad-actions { display: flex; gap: .35rem; }
.pypad-actions button {
  font-family: var(--font-mono);
  font-size: .68rem;
  color: var(--fg-faint);
  padding: .15rem .55rem;
  border: 1px solid var(--line);
  border-radius: 5px;
}
.pypad-actions button:hover { color: var(--fg); border-color: var(--line-strong); }
.pypad-actions .pypad-run {
  color: var(--bg-deep);
  background: var(--accent);
  border-color: var(--accent);
  font-weight: 700;
}
.pypad-actions .pypad-run:hover { color: var(--bg-deep); filter: brightness(1.1); }
.pypad-actions .pypad-run:disabled { opacity: .5; cursor: wait; }
.pypad-editor { padding: .4rem 0; }
.pypad-code {
  display: block;
  width: 100%;
  border: none;
  outline: none;
  resize: none;
  background: transparent;
  color: var(--fg);
  font: inherit;
  line-height: 1.55;
  padding: .5rem 1rem;
  min-height: 80px;
  caret-color: var(--ansi-blue);
  tab-size: 4;
}
.pypad-output {
  border-top: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 55%, var(--bg-deep));
  padding: .7rem 1rem;
  min-height: 2.4rem;
  max-height: 300px;
  overflow-y: auto;
  white-space: pre-wrap;
  word-break: break-word;
  line-height: 1.5;
}
.pypad-placeholder { color: var(--fg-faint); font-style: italic; }
.pypad-loading { color: var(--ansi-yellow); }
.pypad-err { color: var(--ansi-red); }

/* ---------- codex ---------- */
.codex-tabs {
  display: flex;
  align-items: center;
  gap: .4rem;
  margin: 1.5rem 0 1.2rem;
  flex-wrap: wrap;
}
.codex-tabs a {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--fg-dim);
  padding: .35rem .8rem;
  border: 1px solid var(--line);
  border-radius: 99px;
}
.codex-tabs a:hover { color: var(--fg); text-decoration: none; border-color: var(--line-strong); }
.codex-tabs a.active { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 50%, var(--line)); background: var(--panel); }
.codex-filter {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: .8rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--fg);
  padding: .4rem .8rem;
  min-width: 240px;
  outline: none;
}
.codex-filter:focus { border-color: var(--ansi-cyan); }
.codex-grid { columns: 2 460px; column-gap: 1.6rem; }
.codex-sec {
  break-inside: avoid;
  margin-bottom: 1.6rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1rem 1.2rem;
}
.codex-sec h3 {
  margin: 0 0 .6rem;
  font-size: .82rem;
  color: var(--ansi-yellow);
  letter-spacing: .06em;
  text-transform: uppercase;
}
.codex-entry {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: .8rem;
  padding: .3rem .2rem;
  border-radius: 5px;
  align-items: baseline;
}
.codex-entry:hover { background: var(--panel-2); }
.codex-entry code {
  background: none;
  border: none;
  padding: 0;
  color: var(--fg);
  font-size: .78rem;
  white-space: pre-wrap;
  word-break: break-word;
}
.codex-entry span {
  font-size: .78rem;
  color: var(--fg-dim);
  font-family: var(--font-sans);
}

/* ---------- daily drill ---------- */
.nav-due {
  display: inline-block;
  min-width: 1.15em;
  padding: 0 .3em;
  margin-left: .15em;
  text-align: center;
  border-radius: 99px;
  background: var(--ansi-yellow);
  color: var(--bg-deep);
  font-size: .7rem;
  font-weight: 700;
  line-height: 1.5;
}

.drill-strip { margin-top: 2.2rem; }
.drill-strip.clear p {
  font-family: var(--font-mono);
  font-size: .82rem;
  color: var(--fg-dim);
  margin: 0;
}
.drill-strip.clear a { color: var(--accent); }
.drill-card {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  padding: 1rem 1.3rem;
  background: var(--panel);
  border: 1px solid color-mix(in srgb, var(--ansi-yellow) 35%, var(--line-strong));
  border-radius: var(--radius-lg);
  color: var(--fg);
}
.drill-card:hover { text-decoration: none; border-color: var(--ansi-yellow); background: var(--panel-2); }
.drill-glyph { font-size: 1.5rem; }
.drill-copy { display: flex; flex-direction: column; gap: .15rem; flex: 1; }
.drill-copy b { font-family: var(--font-mono); font-size: .95rem; }
.drill-copy span { font-size: .84rem; color: var(--fg-dim); }

.drill-page .drill-head {
  display: flex;
  align-items: baseline;
  gap: 1.2rem;
  flex-wrap: wrap;
}
.drill-bar {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  letter-spacing: .2em;
  color: var(--fg-faint);
}
.drill-bar .hit { color: var(--ansi-green); }
.drill-bar .cur { color: var(--ansi-yellow); }
.drill-bar .miss { color: var(--ansi-red); }

/* ---------- the permission prompt: the house game ---------- */
.perm-strip { margin-top: 2.5rem; }
.permcard {
  border: 1px solid var(--line-strong);
  border-left: 3px solid var(--ansi-yellow);
  border-radius: var(--radius);
  background: var(--panel);
  padding: 1rem 1.1rem;
  max-width: 44rem;
}
.permcard.right { border-left-color: var(--ansi-green); }
.permcard.wrong { border-left-color: var(--ansi-red); }
.perm-head {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--fg-dim);
}
.perm-dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--ansi-yellow);
  animation: perm-pulse 1.8s ease-in-out infinite;
}
.permcard.settled .perm-dot { animation: none; }
.permcard.right .perm-dot { background: var(--ansi-green); }
.permcard.wrong .perm-dot { background: var(--ansi-red); }
@keyframes perm-pulse { 0%, 100% { opacity: 1; } 50% { opacity: .25; } }
.perm-tag {
  margin-left: auto;
  font-size: .68rem;
  color: var(--fg-faint);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: .05rem .5rem;
}
.perm-intent {
  font-style: italic;
  color: var(--fg-dim);
  margin: .7rem 0 .6rem;
  font-size: .92rem;
}
.perm-cmd {
  background: var(--bg-deep);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: .7rem .8rem;
  margin: 0 0 .9rem;
  overflow-x: auto;
  font-size: .92rem;
}
.perm-cmd code { font-family: var(--font-mono); color: var(--fg); white-space: pre; }
.perm-cmd .p { color: var(--accent); }
.perm-actions { display: flex; gap: .6rem; align-items: center; flex-wrap: wrap; }
.perm-btn {
  font-family: var(--font-mono);
  font-size: .85rem;
  padding: .45rem .9rem;
  border-radius: 6px;
  background: var(--panel-2);
  border: 1px solid var(--line-strong);
  color: var(--fg-dim);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: .5rem;
}
.perm-btn b {
  font-weight: 600;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  padding: 0 .3rem;
  font-size: .78rem;
}
.perm-btn.allow:hover { color: var(--ansi-green); border-color: var(--ansi-green); }
.perm-btn.deny:hover { color: var(--ansi-red); border-color: var(--ansi-red); }
.perm-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.perm-chose { font-family: var(--font-mono); font-size: .8rem; color: var(--fg-faint); }
.perm-chose b { color: var(--fg-dim); }
.perm-keys { font-family: var(--font-mono); font-size: .72rem; color: var(--fg-faint); margin: .7rem 0 0; }
.perm-keys kbd {
  font-family: var(--font-mono);
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: 0 .28rem;
  color: var(--fg-dim);
}
.perm-reveal { margin-top: .9rem; padding-top: .9rem; border-top: 1px solid var(--line); }
.perm-verdict { font-family: var(--font-mono); font-size: .85rem; margin: 0 0 .5rem; color: var(--fg-dim); }
.permcard.right .perm-verdict { color: var(--ansi-green); }
.permcard.wrong .perm-verdict { color: var(--ansi-red); }
.perm-verdict b { color: var(--fg); }
.perm-why { margin: 0 0 .6rem; font-size: .93rem; color: var(--fg); }
.perm-tell {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--fg-dim);
  background: var(--panel-2);
  border-radius: 6px;
  padding: .45rem .6rem;
  margin: 0 0 .6rem;
}
.perm-tell span {
  color: var(--ansi-yellow);
  text-transform: uppercase;
  letter-spacing: .08em;
  font-size: .68rem;
  margin-right: .5rem;
}
.perm-learn { font-family: var(--font-mono); font-size: .76rem; color: var(--fg-faint); margin: 0 0 .9rem; }
.perm-warn {
  font-family: var(--font-mono);
  font-size: .82rem;
  color: var(--fg-dim);
  border-left: 2px solid var(--ansi-yellow);
  padding-left: .8rem;
  margin: 1.2rem 0 0;
  max-width: var(--prose);
}
.drill-context {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--fg-faint);
  margin: .2rem 0 1.2rem;
}
.drill-context a { color: var(--fg-dim); }
.drill-foot { margin-top: 1rem; }
.drill-foot .btn { font-size: .78rem; }

.exercise.review .ex-badge { background: var(--ansi-yellow); color: var(--bg-deep); }
.exercise.review.done .ex-badge { background: var(--ansi-green); }

/* ---------- JsPad live preview ---------- */
.jspad-preview {
  border-top: 1px solid var(--line);
  background: var(--bg-deep);
  padding: .6rem .9rem .8rem;
}
.jspad-preview-label {
  display: block;
  font-family: var(--font-mono);
  font-size: .68rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--fg-faint);
  margin-bottom: .45rem;
}
.jspad-frame {
  width: 100%;
  height: 150px;
  border: 1px dashed var(--line-strong);
  border-radius: 6px;
  background: var(--bg);
}

/* ---------- responsive topbar (the 984px hard floor, removed) ---------- */
@media (max-width: 1024px) {
  .topbar { flex-wrap: wrap; gap: .4rem .8rem; padding: .5rem .8rem; }
  /* five items fit now that courses and tools are grouped — wrap instead of
     scrolling, because an overflow container would clip the dropdown panels */
  .topbar nav {
    order: 3;
    flex-basis: 100%;
    margin-left: 0;
    flex-wrap: wrap;
  }
  .topbar nav a, .navgroup-btn { flex-shrink: 0; padding: .3rem .55rem; }
  .topbar .stats { gap: .6rem; font-size: .72rem; }
  .topbar .stats { gap: .6rem; font-size: .72rem; }
}
@media (max-width: 720px) {
  /* 16px floor stops iOS zoom-on-focus; code blocks scroll instead of clip */
  .term-input, .pypad-code { font-size: 16px; }
  pre.shell { overflow-x: auto; }
  .lesson-nav { flex-direction: column; gap: .6rem; align-items: stretch; }
  .lesson-nav a { text-align: center; }
}

/* grid/flex children may not force the page wider than the viewport:
   terminals shrink to their cell and scroll their content instead */
.hero > * { min-width: 0; }
.term { min-width: 0; max-width: 100%; }
.term-screen { overflow-x: auto; }
.ex-body { min-width: 0; }

/* ---------- wave-5 polish ---------- */
/* quizzes are peers of exercises, not trivia footnotes */
.quiz-head { display: flex; align-items: center; gap: .7rem; margin-bottom: .7rem; }
.quiz-badge {
  font-family: var(--font-mono);
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .1em;
  padding: .18rem .5rem;
  border-radius: 5px;
  background: var(--ansi-cyan);
  color: var(--bg-deep);
}
.quiz-xp { margin-left: auto; font-family: var(--font-mono); font-size: .78rem; color: var(--xp); }
.quiz-choice .ql { color: var(--fg-faint); font-family: var(--font-mono); margin-right: .35rem; }

/* the next lesson is the page's primary action — dress it like one */
.lesson-nav a.next {
  background: var(--panel);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: .6rem 1.1rem;
  font-weight: 600;
}
.lesson-nav a.next:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }

/* reference descriptions wrap instead of self-truncating */
.ref-cat a .sum { white-space: normal; }

/* consistent air between dashboard sections */
.page > section + section { margin-top: 2.8rem; }

/* codex empty state */
.codex-empty { font-family: var(--font-mono); font-size: .85rem; color: var(--fg-dim); margin-top: 2rem; }

/* lesson breadcrumb escape hatch to the codex */
.crumb-codex { float: right; font-size: .78rem; color: var(--fg-dim); }
.crumb-codex:hover { color: var(--accent); }

.badge-more { justify-content: center; }