/* ===== Academy "field manual": the classic study layout core (CARTRIDGE design system, tokens in /theme.css) =====
   Shared by IT Academy and AI Academy. Console chrome (top bar, sidebar) + the printed manual (lesson pages).
   Code, editors and program output are CRT screens in BOTH themes. Only --k-* tokens are used for chrome colour;
   the --syn-* values below are syntax-highlighting colours (content) tuned for the dark phosphor screen. */
:root {
  --side-w: 300px;
  --top-h: 60px;
  --syn-kw: #ff9ecb; --syn-str: #b6f08a; --syn-num: #ffb86b; --syn-com: #86a58a; --syn-def: #7fd6ff; --syn-builtin: #ffd866; --syn-op: #9fe8ff;
}
* { box-sizing: border-box; }
html { scroll-padding-top: calc(var(--top-h) + 22px); }
body { margin: 0; font-family: var(--k-body); background: var(--k-dots), var(--k-bg); color: var(--k-text); font-size: 16.5px; line-height: 1.65; -webkit-font-smoothing: antialiased; }
::selection { background: var(--k-coin); color: var(--k-on-accent); }
a { color: var(--k-link); text-decoration: none; text-underline-offset: 2px; }
a:hover { text-decoration: underline; }
code, kbd, pre { font-family: var(--k-mono); font-size: .9em; }
:not(pre) > code { background: var(--k-inset); color: var(--k-text); border: 1px solid var(--k-hair); padding: .08em .38em; border-radius: var(--k-r-xs); font-size: .86em; }
kbd { border: var(--k-border); border-bottom-width: 4px; border-radius: var(--k-r-xs); padding: 0 .4em; font-size: .8em; background: var(--k-panel); color: var(--k-text); }
h1, h2, h3 { font-family: var(--k-display); font-weight: 400; line-height: 1.05; letter-spacing: .015em; }
h1 { font-size: clamp(2.5rem, 4.6vw, 3.3rem); margin: .15em 0 .25em; }
h2 { font-size: 2rem; margin: 1.8em 0 .5em; }
h3 { font-size: 1.5rem; margin: 1.3em 0 .35em; }
h1 code, h2 code, h3 code { font-size: .62em; vertical-align: .12em; }
strong, b { font-weight: 700; }
.muted { color: var(--k-muted); }
.small { font-size: .88rem; }
.grow { flex: 1; }
.test-results[hidden], .output[hidden], .explain[hidden], .scrim[hidden], .search-results[hidden], .py-status[hidden] { display: none; }
.skip-link { position: absolute; left: -999px; top: 8px; z-index: 100; background: var(--k-coin); color: var(--k-on-accent); padding: 10px 14px; border: var(--k-border); border-radius: var(--k-r-sm); font-weight: 700; }
.skip-link:focus { left: 8px; }
:focus-visible { outline: 3px solid var(--k-coin); outline-offset: 2px; }
[data-theme="light"] :focus-visible { outline-color: var(--k-link); }

/* ----- Top bar: the console's status strip ----- */
.topbar { position: sticky; top: 0; z-index: 30; height: var(--top-h); display: flex; align-items: center; gap: 10px; padding: 0 16px;
  background: var(--k-chrome); color: var(--k-text); border-bottom: var(--k-border); }
/* five-colour cartridge trim hanging under the bar (::after is taken by the app shell's wrap spacer) */
.topbar::before { content: ""; position: absolute; left: 0; right: 0; bottom: -7px; height: 5px; background: var(--k-stripes); border-bottom: var(--k-border); pointer-events: none; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--k-text); white-space: nowrap; font: 400 1.75rem/1 var(--k-display); letter-spacing: .04em; text-transform: uppercase; }
.brand:hover { text-decoration: none; }
.brand:hover .brand-logo { background: var(--k-inset); }
.brand-logo { display: inline-flex; align-items: center; height: 40px; padding: 0 8px; font-size: 1.15rem; letter-spacing: .12em; line-height: 1;
  background: var(--k-panel); border: var(--k-border); border-radius: var(--k-r-sm); box-shadow: var(--k-drop-sm); }
.search-wrap { position: relative; flex: 1; max-width: 520px; margin-left: 12px; }
#searchInput { width: 100%; height: 44px; padding: 0 14px; border-radius: var(--k-r-sm); border: var(--k-border); background: var(--k-inset); color: var(--k-text); font: inherit; font-size: .95rem;
  box-shadow: inset 2px 2px 0 var(--k-hair); }
#searchInput::placeholder { color: var(--k-muted); opacity: 1; }
#searchInput:focus { background: var(--k-panel); }
/* the box is often squeezed by the status chips: while typing it grows over its neighbours */
.search-wrap:focus-within #searchInput { position: relative; z-index: 2; width: max(100%, min(340px, 62vw)); }
.search-wrap:focus-within .search-results { z-index: 3; }
.search-results { position: absolute; top: calc(100% + 10px); left: 0; right: 0; min-width: min(320px, calc(100vw - 24px)); background: var(--k-panel); color: var(--k-text); border: var(--k-border); border-radius: var(--k-r);
  box-shadow: var(--k-drop-lg); max-height: 70vh; overflow: auto; padding: 6px; }
.sr-item, .sr-all { display: block; padding: 8px 10px; border-radius: var(--k-r-sm); color: var(--k-text); border: 2px solid transparent; }
.sr-item + .sr-item { margin-top: 2px; }
.sr-item strong { font-weight: 700; }
.sr-item:hover { background: var(--k-inset); text-decoration: none; }
.sr-item.sel { background: var(--k-coin); color: var(--k-on-accent); border-color: var(--k-line); text-decoration: none; }
.sr-item .snip { display: block; color: var(--k-muted); font-size: .84rem; line-height: 1.45; margin-top: 2px; }
.sr-item.sel .snip { color: var(--k-on-accent); }
.sr-item.sel mark { background: var(--k-cream); }
.sr-all { display: flex; align-items: center; color: var(--k-link); font: 400 1.2rem var(--k-display); letter-spacing: .03em; border-top: 2px dashed var(--k-hair); border-radius: 0 0 var(--k-r-sm) var(--k-r-sm); margin-top: 6px; }
.sr-all:hover { background: var(--k-inset); text-decoration: none; }
.sr-empty { padding: 12px; color: var(--k-muted); }
mark { background: var(--k-coin); color: var(--k-on-accent); border-radius: 3px; padding: 0 2px; }
.topbar-right { margin-left: auto; display: flex; align-items: center; gap: 10px; }
/* Python runtime status: a little LCD with a state LED */
.py-status { display: inline-flex; align-items: center; gap: 7px; height: 32px; padding: 0 11px 1px; white-space: nowrap; font: 400 1.1rem/1 var(--k-display); letter-spacing: .05em;
  background: var(--k-screen); color: var(--k-phos-dim); border: var(--k-border); border-radius: var(--k-r-sm); }
.py-status::before { content: ""; flex: none; width: 8px; height: 8px; border-radius: 50%; background: var(--k-phos-dim); }
.py-status[data-state="ready"] { color: var(--k-phos-hot); }
.py-status[data-state="ready"]::before { background: var(--k-leaf); box-shadow: 0 0 6px var(--k-leaf); }
.py-status[data-state="loading"], .py-status[data-state="running"] { color: var(--k-coin); }
.py-status[data-state="loading"]::before, .py-status[data-state="running"]::before { background: var(--k-coin); animation: k-led .8s steps(2, jump-none) infinite; }
.py-status[data-state="error"] { color: var(--k-heart); }
.py-status[data-state="error"]::before { background: var(--k-heart); }
@keyframes k-led { 50% { opacity: .25; } }
.icon-btn { display: inline-flex; align-items: center; justify-content: center; width: 44px; height: 44px; padding: 0; font-size: 1.15rem; line-height: 1; cursor: pointer; color: var(--k-text); text-decoration: none;
  background: var(--k-panel); border: var(--k-border); border-radius: var(--k-r-sm); box-shadow: var(--k-drop-sm); transition: transform .08s, box-shadow .08s, background .08s; }
.icon-btn:hover { background: var(--k-inset); text-decoration: none; }
.icon-btn:active { transform: translate(2px, 2px); box-shadow: none; }
.icon-btn[aria-pressed="true"] { background: var(--k-leaf); color: var(--k-on-accent); }
.menu-btn { display: none; }
.menu-btn[aria-expanded="true"] { background: var(--k-coin); color: var(--k-on-accent); }

/* ----- Layout ----- */
.layout { display: flex; min-height: calc(100vh - var(--top-h)); }
.sidebar { width: var(--side-w); flex-shrink: 0; position: sticky; top: var(--top-h); height: calc(100vh - var(--top-h)); overflow-y: auto;
  border-right: var(--k-border); background: var(--k-chrome); color: var(--k-text); padding: 20px 12px 40px; font-size: .92rem; scrollbar-width: thin; scrollbar-color: var(--k-hair) transparent; }
.content { flex: 1; min-width: 0; padding: 34px clamp(18px, 4vw, 56px) 80px; max-width: 980px; outline: none; }
/* main menu: chunky console menu items */
.side-links { display: grid; gap: 2px; }
.side-links a { display: flex; align-items: center; gap: 6px; padding: 4px 10px; border-radius: var(--k-r-sm); color: var(--k-text); border: 2px solid transparent;
  font: 400 1.24rem/1.15 var(--k-display); letter-spacing: .03em; }
.side-links a:hover, .side-level a:hover, .side-level summary:hover { background: var(--k-inset); text-decoration: none; }
.side-links a[aria-current="page"], .side-level a[aria-current="page"] { background: var(--k-brand); color: var(--k-on-accent); border-color: var(--k-line); box-shadow: var(--k-drop-sm); }
.side-links .side-count { margin-left: auto; }
.side-links a[aria-current="page"] .side-count { background: var(--k-cream); color: var(--k-black); border-color: var(--k-black); }
.side-overall { margin: 14px 10px 8px; font-size: .86rem; color: var(--k-muted); }
.side-overall-top { display: flex; justify-content: space-between; margin-bottom: 4px; }
/* chapters */
.side-level { margin-top: 6px; border-top: 2px dashed var(--k-hair); padding-top: 6px; }
.side-level summary { cursor: pointer; display: flex; align-items: center; justify-content: space-between; gap: 6px; padding: 6px 10px; border-radius: var(--k-r-sm); list-style: none;
  font: 400 1.3rem/1.15 var(--k-display); letter-spacing: .03em; }
.side-level summary::-webkit-details-marker { display: none; }
.side-level summary::before { content: "▸"; flex: none; width: 22px; height: 22px; display: inline-grid; place-items: center; margin-right: 2px; font-size: 1rem; color: var(--k-text);
  background: var(--k-panel); border: var(--k-border); border-radius: var(--k-r-xs); transition: transform .15s; }
.side-level[open] summary::before { transform: rotate(90deg); background: var(--k-coin); color: var(--k-on-accent); }
.side-level summary span:first-child { flex: 1; }
.side-count { flex: none; padding: 0 7px 1px; color: var(--k-muted); background: var(--k-inset); border: 1px solid var(--k-hair); border-radius: 999px; font: 400 1.02rem/1.35 var(--k-display); letter-spacing: .04em; white-space: nowrap; }
.side-level > .pbar { margin: 2px 10px 8px; height: 9px; padding: 1px; }
.side-level ol { list-style: none; margin: 0; padding: 0 0 6px; display: grid; gap: 1px; }
.side-level a { display: flex; gap: 6px; padding: 4px 10px; border-radius: var(--k-r-sm); border: 2px solid transparent; color: var(--k-muted); line-height: 1.35; }
.side-level a:hover { color: var(--k-text); }
.side-level a[aria-current="page"] { font-weight: 700; opacity: 1; }
.tick { width: 18px; flex-shrink: 0; text-align: center; color: var(--k-ok); font-weight: 800; }
.side-level a[aria-current="page"] .tick { color: var(--k-on-accent); }
.scrim { position: fixed; inset: var(--top-h) 0 0 0; z-index: 19; background: color-mix(in srgb, var(--k-black) 62%, transparent); }

/* ----- Cards, buttons, bars ----- */
.card { background: var(--k-panel); color: var(--k-text); border: var(--k-border); border-radius: var(--k-r); box-shadow: var(--k-drop-md); }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; min-height: 44px; padding: 0 15px; cursor: pointer; text-decoration: none; white-space: nowrap;
  font: 400 1.25rem/1 var(--k-display); letter-spacing: .03em; color: var(--k-text); background: var(--k-panel); border: var(--k-border); border-radius: var(--k-r-sm); box-shadow: var(--k-drop-sm);
  transition: transform .08s, box-shadow .08s, background .08s; }
.btn:hover { background: var(--k-inset); text-decoration: none; }
.btn:active { transform: translate(2px, 2px); box-shadow: none; }
.btn:disabled { opacity: .6; cursor: progress; transform: none; box-shadow: var(--k-drop-sm); }
.btn.primary { background: var(--k-coin); color: var(--k-on-accent); }
.btn.primary:hover { background: var(--k-coin); filter: brightness(1.08); }
.btn.ghost { background: transparent; box-shadow: none; border-style: dashed; }
.btn.ghost:hover { background: var(--k-inset); border-style: solid; }
.btn.ghost:active { transform: translate(1px, 1px); }
.btn.danger { background: var(--k-heart); color: var(--k-on-accent); }
.btn.danger:hover { background: var(--k-heart); filter: brightness(1.08); }
.btn.big { min-height: 52px; padding: 0 22px; font-size: 1.5rem; box-shadow: var(--k-drop-md); }
.btn.big:active { box-shadow: none; }
.btn.tiny { padding: 0 10px; font-size: 1.08rem; }
.btn.is-done, .btn.is-done:hover { background: var(--k-leaf); color: var(--k-on-accent); filter: none; }
.badge { display: inline-block; vertical-align: middle; padding: 1px 8px 2px; border-radius: 6px; white-space: nowrap; font: 400 1.02rem/1.25 var(--k-display); letter-spacing: .05em;
  background: var(--k-inset); border: 1px solid var(--k-line); color: var(--k-text); }
.badge.run { background: var(--k-leaf); color: var(--k-on-accent); border-color: var(--k-line); }
.badge.local { background: var(--k-coin); color: var(--k-on-accent); border-color: var(--k-line); }
/* progress bars are segmented LCD meters */
.pbar { height: 14px; padding: 2px; background: var(--k-screen); border: var(--k-border); border-radius: var(--k-r-xs); overflow: hidden; }
.pbar > span { display: block; height: 100%; min-width: 0; border-radius: 1px; background: repeating-linear-gradient(90deg, var(--k-phos-hot) 0 6px, transparent 6px 8px); transition: width .4s; }

/* ----- Home ----- */
.hero { padding: 20px 0 10px; }
.eyebrow { margin: 0 0 4px; font: 400 1.15rem/1.3 var(--k-display); text-transform: uppercase; letter-spacing: .1em; color: var(--k-brand-text); }
.hero h1 { font-size: clamp(2.2rem, 4vw, 3rem); max-width: 34ch; text-transform: uppercase; letter-spacing: .02em; }
.lead { font-size: 1.1rem; color: var(--k-muted); max-width: 68ch; margin: .4em 0 .8em; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.dash { display: grid; grid-template-columns: 1.4fr 1fr; gap: 22px; margin-top: 30px; }
.dash .card { padding: 18px 20px; min-width: 0; }
.dash h2 { margin: 0 0 8px; font-size: 1.6rem; }
/* the big percentage is an LCD read-out */
.big-pct { display: inline-block; margin: 6px 0 12px; padding: 4px 14px 6px; font: 400 3.4rem/1 var(--k-display); letter-spacing: .03em;
  background: var(--k-screen); color: var(--k-phos-hot); border: var(--k-border); border-radius: var(--k-r-sm); }
.big-pct small { font-size: 1.6rem; color: var(--k-phos-dim); margin-left: 2px; }
.lvl-rows { margin-top: 14px; display: grid; gap: 4px; }
.lvl-row { display: grid; grid-template-columns: 150px 1fr 56px; gap: 12px; align-items: center; color: var(--k-text); font-size: .92rem; padding: 5px 6px; border-radius: var(--k-r-sm); }
.lvl-row:hover { background: var(--k-inset); text-decoration: none; }
.lvl-num { text-align: right; color: var(--k-muted); font: 400 1.15rem/1 var(--k-display); letter-spacing: .04em; }
.howto { padding-left: 20px; margin: 0; font-size: .93rem; }
.howto li { margin: 6px 0; }
.howto li::marker { color: var(--k-brand-text); }
.section-title { margin-top: 2em; padding-bottom: 6px; border-bottom: var(--k-border); }
.level-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px; }
.level-card { padding: 16px 18px; color: var(--k-text); display: flex; flex-direction: column; transition: transform .12s, box-shadow .12s; }
.level-card:hover { text-decoration: none; }
@media (hover: hover) { .level-card:hover { transform: translate(-2px, -2px); box-shadow: var(--k-drop-lg); } }
.level-card:active { transform: translate(2px, 2px); box-shadow: none; }
.level-card h3 { margin: 10px 0 4px; font-size: 1.6rem; }
.level-card p { margin: 0 0 12px; font-size: .92rem; color: var(--k-muted); }
.level-card .pbar { margin-top: auto; }
.lc-icon { align-self: flex-start; width: 52px; height: 52px; display: grid; place-items: center; font-size: 1.7rem; line-height: 1; background: var(--k-cream); border: 2px solid var(--k-black); border-radius: var(--k-r-sm); box-shadow: 2px 2px 0 var(--k-black); }

/* ----- Level page: the chapter index ----- */
.crumbs { margin: 0 0 6px; font: 400 1.1rem/1.4 var(--k-display); letter-spacing: .07em; text-transform: uppercase; color: var(--k-muted); }
.level-head { display: flex; align-items: center; gap: 14px; max-width: 520px; font: 400 1.3rem/1 var(--k-display); letter-spacing: .03em; }
.level-head .pbar { flex: 1; }
.lesson-list { list-style: none; padding: 0; display: grid; gap: 12px; margin-top: 24px; }
.lesson-list > li { box-shadow: var(--k-drop-sm); border-radius: var(--k-r-sm); transition: transform .1s, box-shadow .1s; }
@media (hover: hover) { .lesson-list > li:hover { transform: translate(-2px, -2px); box-shadow: var(--k-drop-md); } }
.lesson-list > li:active { transform: translate(2px, 2px); box-shadow: none; }
.lesson-list a { display: flex; align-items: center; gap: 14px; padding: 10px 14px; color: var(--k-text); border-radius: calc(var(--k-r-sm) - 2px); }
.lesson-list a:hover { text-decoration: none; background: var(--k-inset); }
.ll-num { width: 40px; height: 40px; flex-shrink: 0; display: grid; place-items: center; font: 400 1.45rem/1 var(--k-display); background: var(--k-inset); color: var(--k-text); border: var(--k-border); border-radius: var(--k-r-xs); }
.ll-body { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.ll-body strong { font-size: 1.03rem; line-height: 1.35; }
.ll-body .badge { align-self: flex-start; margin: 2px 0; }
.ll-body .muted { font-size: .9rem; line-height: 1.45; }
.ll-min { flex: none; padding: 1px 8px 2px; white-space: nowrap; font: 400 1.08rem/1.3 var(--k-display); letter-spacing: .04em; color: var(--k-muted); border: 2px dashed var(--k-hair); border-radius: 6px; }

/* ----- Lesson: a page of the field manual ----- */
.lesson { counter-reset: k-sec; }
.lesson-head { position: relative; margin: 10px 0 26px; padding: 25px clamp(14px, 3vw, 26px) 4px; overflow: hidden; background: var(--k-panel); color: var(--k-text); border: var(--k-border); border-radius: var(--k-r); box-shadow: var(--k-drop-md); }
.lesson-head::before { content: ""; position: absolute; left: 0; right: 0; top: 0; height: 7px; background: var(--k-stripes); border-bottom: var(--k-border); }
.lesson-head h1 { margin-top: 0; }
.lesson-head .lead { margin-bottom: 1em; }
.lesson-head .meta { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; margin: 0 calc(-1 * clamp(14px, 3vw, 26px)); padding: 8px clamp(14px, 3vw, 26px); min-height: 62px; color: var(--k-muted); font-size: .9rem;
  background: var(--k-inset); border-top: var(--k-border); margin-bottom: -4px; }
.lesson-head .meta .act-done { margin-left: auto; }
.lesson-body p, .lesson-body li { max-width: 72ch; }
.lesson-body ul, .lesson-body ol { padding-left: 1.4em; }
.lesson-body li { margin: .25em 0; }
.lesson-body li::marker { color: var(--k-brand-text); font-weight: 700; }
.lesson-body a:not(.btn), .callout a:not(.btn), .explain a, .ex-prompt a, .lead a { text-decoration: underline; text-decoration-thickness: 1px; }
/* numbered sections */
.lesson-body > h2, .exercises > h2, .quiz-wrap > h2 { margin: 2em 0 .65em; padding-bottom: 9px; border-bottom: var(--k-border); }
.lesson-body > h2::before, .exercises > h2::before, .quiz-wrap > h2::before { counter-increment: k-sec; content: counter(k-sec, decimal-leading-zero); display: inline-block; margin-right: 12px; padding: 1px 8px 3px; font-size: .78em; letter-spacing: .06em; vertical-align: .08em;
  background: var(--k-brand); color: var(--k-on-accent); border: var(--k-border); border-radius: 6px; box-shadow: var(--k-drop-sm); }
.lesson-body > h3::before { content: "▸ "; color: var(--k-brand-text); }
/* callouts: boxed manual notes with a label tab */
.callout { --co: var(--k-brand); position: relative; margin: 34px 0 22px; padding: 4px 16px 12px 24px; background: var(--k-panel); color: var(--k-text); border: var(--k-border); border-radius: var(--k-r-sm); box-shadow: inset 8px 0 0 var(--co), var(--k-drop-sm); }
.callout p { margin: 4px 0 0; }
.callout-title { display: inline-block; position: relative; top: -15px; margin: 0 0 -9px -4px; padding: 2px 10px 3px; font: 400 1.18rem/1.15 var(--k-display); letter-spacing: .07em; text-transform: uppercase;
  background: var(--co); color: var(--k-on-accent); border: var(--k-border); border-radius: 6px; }
.callout.tip { --co: var(--k-leaf); }
.callout.warn { --co: var(--k-coin); }
.callout.note { --co: var(--k-sky); }
.callout.sysadmin { --co: var(--k-ai); }
.table-wrap { overflow-x: auto; margin: 18px 0; background: var(--k-panel); border: var(--k-border); border-radius: var(--k-r-sm); box-shadow: var(--k-drop-sm); }
html.app-academy .content .table-wrap > table { display: table; }
table { border-collapse: collapse; width: 100%; font-size: .92rem; }
th, td { border-bottom: 1px solid var(--k-hair); padding: 8px 12px; text-align: left; vertical-align: top; }
th { background: var(--k-inset); border-bottom: var(--k-border); font: 400 1.18rem/1.25 var(--k-display); letter-spacing: .04em; vertical-align: bottom; }
tbody tr:nth-child(even) > td { background: color-mix(in srgb, var(--k-inset) 50%, transparent); }
.table-wrap tbody tr:last-child > td { border-bottom: 0; }
.table-wrap th, .table-wrap td, .prog-table th, .prog-table td { overflow-wrap: break-word; }

/* code blocks: a CRT monitor with a label strip on top and a control deck below */
.codeblock, .shell { margin: 22px 0; border: var(--k-border); border-radius: var(--k-r); overflow: hidden; background: var(--k-screen); color: var(--k-phos); box-shadow: var(--k-drop-md); }
.cb-head, .shell figcaption { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 4px 10px; min-height: 42px; padding: 5px 12px; background: var(--k-inset); color: var(--k-text); border-bottom: var(--k-border);
  font: 400 1.25rem/1.2 var(--k-display); letter-spacing: .03em; }
.cb-head > :first-child, .shell figcaption > span:first-child { flex: 1 1 auto; min-width: 0; }
.cb-head > :first-child::before, .shell figcaption > span:first-child::before { content: "▮ "; color: var(--k-brand-text); }
.local-why { padding: 9px 14px; font-size: .88rem; color: var(--k-text); background: linear-gradient(var(--k-warn-bg), var(--k-warn-bg)), var(--k-panel); border-bottom: var(--k-border); box-shadow: inset 6px 0 0 var(--k-coin); padding-left: 18px; }
.shell pre { position: relative; margin: 0; padding: 14px 16px; overflow-x: auto; color: var(--k-phos); background: var(--k-scan), var(--k-screen); line-height: 1.55; }
.cb-tools { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; padding: 10px 12px 12px; border-top: var(--k-border); background: var(--k-panel); color: var(--k-text); }
.hint { color: var(--k-muted); font-size: .8rem; margin-left: auto; }
.stdin-row { padding: 8px 12px; border-top: var(--k-border); background: var(--k-panel); font-size: .82rem; color: var(--k-muted); }
.stdin-row label { display: block; }
.stdin { display: block; width: 100%; margin-top: 4px; font-family: var(--k-mono); font-size: .86rem; background: var(--k-screen); color: var(--k-phos); caret-color: var(--k-phos-hot); border: var(--k-border); border-radius: var(--k-r-xs); padding: 6px 8px; resize: vertical; }
.output { margin: 0; padding: 10px 16px 14px; border-top: var(--k-border); background: var(--k-scan), var(--k-screen); color: var(--k-phos); white-space: pre-wrap; word-break: break-word; max-height: 420px; overflow: auto; font-size: .86rem; line-height: 1.5; }
.output::before { content: "▮ OUTPUT"; display: block; margin-bottom: 6px; font: 400 1rem/1.2 var(--k-display); letter-spacing: .14em; color: var(--k-phos-dim); }
.output .err { color: var(--k-coin); }
.output .exc { color: var(--k-heart); }
.output .muted { color: var(--k-phos-dim); }
.output .run-meta { display: block; margin-top: 8px; color: var(--k-phos-dim); font-size: .75rem; font-family: var(--k-body); }

/* Editor (CodeMirror 5): phosphor screen in both themes */
.editor-host { position: relative; background: var(--k-screen); color: var(--k-phos); }
.editor-host::after { content: ""; position: absolute; inset: 0; z-index: 7; background: var(--k-scan); pointer-events: none; }
.editor-host .CodeMirror { height: auto; font-family: var(--k-mono); font-size: .88rem; line-height: 1.6; background: var(--k-screen); color: var(--k-phos); padding: 8px 0; }
.editor-host .CodeMirror-gutters { background: var(--k-screen-2); border-right: 1px solid var(--k-screen-line); }
.editor-host .CodeMirror-linenumber { color: var(--k-phos-dim); padding: 0 6px 0 8px; }
.editor-host .CodeMirror-cursor { border-left: 2px solid var(--k-phos-hot); }
.editor-host .CodeMirror-selected, .editor-host .CodeMirror-focused .CodeMirror-selected { background: color-mix(in srgb, var(--k-phos-hot) 30%, var(--k-screen)); }
.editor-host .CodeMirror-line::selection, .editor-host .CodeMirror-line > span::selection, .editor-host .CodeMirror-line > span > span::selection,
.code-fallback::selection, .stdin::selection, .output ::selection, .shell pre ::selection, .solution pre ::selection, .cheat pre ::selection { background: color-mix(in srgb, var(--k-phos-hot) 34%, var(--k-screen)); color: var(--k-phos); }
.editor-host .CodeMirror-activeline-background { background: var(--k-screen-2); }
.editor-host .CodeMirror-scrollbar-filler, .editor-host .CodeMirror-gutter-filler { background: var(--k-screen); }
/* focus marker lives on the overlay so the gutter cannot cover it */
.editor-host:focus-within::after { box-shadow: inset 3px 0 0 var(--k-phos-hot); }
.cm-s-default .cm-keyword { color: var(--syn-kw); }
.cm-s-default .cm-string, .cm-s-default .cm-string-2 { color: var(--syn-str); }
.cm-s-default .cm-number { color: var(--syn-num); }
.cm-s-default .cm-comment { color: var(--syn-com); font-style: italic; }
.cm-s-default .cm-def { color: var(--syn-def); }
.cm-s-default .cm-builtin { color: var(--syn-builtin); }
.cm-s-default .cm-variable { color: var(--k-phos); }
.cm-s-default .cm-variable-2 { color: var(--syn-def); }
.cm-s-default .cm-property { color: var(--k-phos); }
.cm-s-default .cm-operator { color: var(--syn-op); }
.cm-s-default .cm-meta { color: var(--syn-builtin); }
.cm-s-default .cm-atom { color: var(--syn-num); }
.cm-s-default .cm-error { color: var(--k-heart); background: none; }
.CodeMirror-matchingbracket { color: var(--k-phos-hot) !important; outline: 1px solid var(--k-phos-dim); }
.code-fallback { display: block; width: 100%; min-height: 80px; border: 0; resize: vertical; padding: 10px 14px; font-family: var(--k-mono); font-size: .88rem; line-height: 1.6; background: var(--k-screen); color: var(--k-phos); caret-color: var(--k-phos-hot); tab-size: 4; white-space: pre; overflow-x: auto; }

/* Exercises: challenge cards with a header strip */
.exercise { padding: 0 18px 16px; margin: 24px 0; }
.exercise .codeblock, .exercise .editor-host { border-radius: var(--k-r-sm); }
.exercise .editor-host { border: var(--k-border); overflow: hidden; margin-top: 12px; }
.exercise .cb-tools, .exercise .stdin-row { background: transparent; border: 0; padding: 12px 0 0; }
.exercise .output { border: var(--k-border); border-radius: var(--k-r-sm); margin-top: 12px; }
.ex-head { display: flex; justify-content: space-between; align-items: center; gap: 6px 10px; flex-wrap: wrap; margin: 0 -18px 12px; padding: 9px 18px 10px; background: var(--k-inset); border-bottom: var(--k-border); border-radius: calc(var(--k-r) - 2px) calc(var(--k-r) - 2px) 0 0; }
.ex-head h3 { margin: 0; font-size: 1.55rem; }
.ex-status { flex: none; padding: 2px 10px 3px; font: 400 1.08rem/1.25 var(--k-display); letter-spacing: .05em; color: var(--k-muted); background: var(--k-panel); border: 2px dashed var(--k-muted); border-radius: 999px; }
.ex-status.passed { color: var(--k-on-accent); background: var(--k-leaf); border: var(--k-border); }
.ex-status.failed { color: var(--k-on-accent); background: var(--k-heart); border: var(--k-border); }
.exercise.is-pass { box-shadow: 4px 4px 0 var(--k-leaf); }
.exercise.is-pass .ex-head { background: linear-gradient(var(--k-ok-bg), var(--k-ok-bg)), var(--k-inset); }
.exercise.is-fail { box-shadow: 4px 4px 0 var(--k-heart); }
.exercise.is-fail .ex-head { background: linear-gradient(var(--k-bad-bg), var(--k-bad-bg)), var(--k-inset); }
.ex-prompt p { margin: .4em 0; }
.test-results { list-style: none; padding: 0; margin: 12px 0 0; display: grid; gap: 6px; }
.test-results li { display: flex; gap: 10px; padding: 7px 12px; border-radius: var(--k-r-xs); font-size: .9rem; border: 1px solid var(--k-hair); }
.test-results li.pass { background: var(--k-ok-bg); border-color: var(--k-ok); box-shadow: inset 5px 0 0 var(--k-ok); }
.test-results li.fail { background: var(--k-bad-bg); border-color: var(--k-bad); box-shadow: inset 5px 0 0 var(--k-bad); }
.test-results .ti { font-weight: 800; }
.test-results li.pass .ti { color: var(--k-ok); }
.test-results li.fail .ti { color: var(--k-bad); }
.test-results .msg { font-family: var(--k-mono); font-size: .8rem; color: var(--k-muted); white-space: pre-wrap; }
.solution { margin-top: 14px; padding: 0 12px; font-size: .9rem; border: 2px dashed var(--k-hair); border-radius: var(--k-r-sm); }
.solution[open] { padding-bottom: 12px; }
.solution summary { min-height: 44px; display: flex; align-items: center; gap: 8px; cursor: pointer; color: var(--k-link); font: 400 1.2rem var(--k-display); letter-spacing: .03em; list-style: none; }
.solution summary::-webkit-details-marker { display: none; }
.solution summary::before { content: "▸"; display: inline-block; transition: transform .15s; }
.solution[open] summary::before { transform: rotate(90deg); }
.solution pre { margin: 2px 0 10px; background: var(--k-scan), var(--k-screen); color: var(--k-phos); border: var(--k-border); border-radius: var(--k-r-sm); padding: 10px 14px; overflow-x: auto; }

/* Quiz */
.quiz { padding: 4px 20px 18px; }
.q { border: 0; border-bottom: 2px dashed var(--k-hair); padding: 16px 0; margin: 0; min-width: 0; }
.q legend { font-weight: 600; font-size: 1.04rem; padding: 0; margin-bottom: 10px; float: left; width: 100%; }
.q legend + * { clear: both; }
.qn { display: inline-block; min-width: 30px; margin-right: 6px; padding: 0 6px 2px; text-align: center; font: 400 1.3rem/1.25 var(--k-display); background: var(--k-coin); color: var(--k-on-accent); border: var(--k-border); border-radius: 6px; }
.opt { display: flex; align-items: flex-start; gap: 10px; margin-top: 6px; padding: 9px 12px; min-height: 44px; border-radius: var(--k-r-sm); cursor: pointer; border: 2px solid var(--k-hair); background: var(--k-panel); transition: background .08s, border-color .08s; }
.opt:hover { background: var(--k-inset); border-color: var(--k-muted); }
.opt > span { flex: 1; min-width: 0; }
.opt input { -webkit-appearance: none; appearance: none; flex: none; display: grid; place-content: center; width: 22px; height: 22px; margin: 2px 0 0; cursor: pointer; background: var(--k-panel); border: var(--k-border); border-radius: 50%; }
.opt input::before { content: ""; width: 10px; height: 10px; border-radius: 50%; background: var(--k-line); transform: scale(0); transition: transform .1s; }
.opt input:checked::before { transform: scale(1); }
.opt:has(input:checked) { border-color: var(--k-line); background: var(--k-inset); box-shadow: var(--k-drop-sm); }
.q .opt.correct, .q .opt.correct:hover { border-color: var(--k-ok); background: var(--k-ok-bg); }
.q .opt.wrong, .q .opt.wrong:hover { border-color: var(--k-bad); background: var(--k-bad-bg); }
.opt.correct::after, .opt.wrong::after { flex: none; width: 26px; height: 26px; display: grid; place-items: center; font: 400 1.3rem/1 var(--k-display); color: var(--k-on-accent); border: 2px solid var(--k-line); border-radius: 6px; }
.opt.correct::after { content: "✓"; background: var(--k-leaf); }
.opt.wrong::after { content: "✗"; background: var(--k-heart); }
.explain { margin-top: 10px; padding: 9px 12px 9px 18px; border-radius: var(--k-r-xs); background: var(--k-inset); border: 1px solid var(--k-hair); box-shadow: inset 6px 0 0 var(--k-muted); font-size: .92rem; }
.q.is-right .explain { box-shadow: inset 6px 0 0 var(--k-leaf); }
.q.is-wrong .explain { box-shadow: inset 6px 0 0 var(--k-heart); }
.q.is-right .explain strong { color: var(--k-ok); }
.q.is-wrong .explain strong { color: var(--k-bad); }
.quiz-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 16px; }
.quiz-score { font: 400 1.35rem/1.2 var(--k-display); letter-spacing: .03em; }

/* checkpoint + prev/next */
.lesson-done { position: relative; display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 23px 20px 16px; margin-top: 40px; flex-wrap: wrap; overflow: hidden; }
.lesson-done::before { content: ""; position: absolute; left: 0; right: 0; top: 0; height: 7px; background: var(--k-stripes); border-bottom: var(--k-border); }
.lesson-done strong { font: 400 1.6rem/1.15 var(--k-display); letter-spacing: .02em; }
.lesson-done p { margin: 2px 0 0; }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 22px; }
.pager a { display: flex; flex-direction: column; gap: 2px; min-width: 0; padding: 12px 16px 14px; color: var(--k-text); transition: transform .1s, box-shadow .1s; }
.pager a .small { font: 400 1.08rem/1.3 var(--k-display); letter-spacing: .1em; text-transform: uppercase; }
.pager a strong { font: 400 1.4rem/1.15 var(--k-display); letter-spacing: .02em; }
.pager a:hover { text-decoration: none; background: var(--k-inset); }
@media (hover: hover) { .pager a:hover { transform: translate(-2px, -2px); box-shadow: var(--k-drop-lg); } }
.pager a:active { transform: translate(2px, 2px); box-shadow: none; }
.pager-next { text-align: right; }

/* Progress page: the save file */
.prog-summary { display: flex; gap: 12px 24px; align-items: center; padding: 18px 22px; flex-wrap: wrap; }
.prog-summary .big-pct { margin: 0; }
.prog-summary .grow { min-width: min(100%, 240px); }
.prog-summary .btn { margin-top: 6px; }
.prog-level { padding: 0 20px 16px; margin-top: 22px; }
.prog-level h2 { margin: 0; font-size: 1.55rem; }
.prog-level-head { display: flex; justify-content: space-between; align-items: center; gap: 10px; margin: 0 -20px 14px; padding: 9px 20px 10px; color: var(--k-text); background: var(--k-inset); border-bottom: var(--k-border); border-radius: calc(var(--k-r) - 2px) calc(var(--k-r) - 2px) 0 0; }
.prog-level-head > span { flex: none; font: 400 1.25rem/1 var(--k-display); letter-spacing: .04em; color: var(--k-muted); }
.prog-level > :first-child:not(.prog-level-head) { margin-top: 16px; }
.prog-table { margin-top: 14px; }
html.app-academy .content .prog-table { display: table; }
.prog-table td:first-child, .prog-table th:first-child { width: 64px; text-align: center; overflow-wrap: normal; }
.prog-table td { vertical-align: middle; }
.prog-table input[type="checkbox"] { -webkit-appearance: none; appearance: none; position: relative; display: inline-grid; place-content: center; width: 26px; height: 26px; margin: 0; vertical-align: middle; cursor: pointer; background: var(--k-panel); border: var(--k-border); border-radius: var(--k-r-xs); }
.prog-table input[type="checkbox"]::before { content: "✓"; font: 800 1rem/1 var(--k-body); color: var(--k-on-accent); transform: scale(0); transition: transform .1s; }
.prog-table input[type="checkbox"]:checked { background: var(--k-leaf); }
.prog-table input[type="checkbox"]::after { content: ""; position: absolute; inset: -9px; }   /* 44px tap target */
.prog-table input[type="checkbox"]:checked::before { transform: scale(1); }

/* Cheat sheet & glossary: reference cards */
.cheat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(380px, 1fr)); gap: 22px; }
.cheat { padding: 0 16px 14px; overflow: hidden; min-width: 0; }
.cheat h2 { margin: 0 -16px 12px; padding: 9px 16px 10px; font-size: 1.5rem; background: var(--k-inset); border-bottom: var(--k-border); }
.cheat pre { background: var(--k-scan), var(--k-screen); color: var(--k-phos); border: var(--k-border); border-radius: var(--k-r-sm); padding: 10px 12px; overflow-x: auto; font-size: .82rem; line-height: 1.5; margin: 0; }
.cheat .table-wrap { box-shadow: none; margin: 0 0 4px; }
.cheat table code { background: none; border: 0; padding: 0; }
.glossary-filter, .search-page-form input { width: 100%; max-width: 420px; min-height: 46px; padding: 0 14px; border-radius: var(--k-r-sm); border: var(--k-border); background: var(--k-panel); color: var(--k-text); font: inherit; box-shadow: inset 2px 2px 0 var(--k-hair); }
.glossary-filter::placeholder, .search-page-form input::placeholder { color: var(--k-muted); opacity: 1; }
.search-page-form { display: flex; gap: 10px; align-items: center; }
.search-page-form input { flex: 1 1 auto; min-width: 0; }
.glossary { display: grid; gap: 12px; margin-top: 20px; }
.g-item { padding: 12px 16px; border-radius: var(--k-r-sm); box-shadow: var(--k-drop-sm); }
.g-item dt { font-weight: 700; font-family: var(--k-mono); color: var(--k-brand-text); display: flex; flex-wrap: wrap; align-items: center; gap: 4px 10px; }
.g-item dd { margin: 4px 0 0; }
.g-item.flash { animation: flash 2s; }
@keyframes flash { 0%, 40% { background: var(--k-warn-bg); box-shadow: 0 0 0 4px var(--k-coin), var(--k-drop-sm); } }
.search-list { list-style: none; padding: 0; display: grid; gap: 12px; }
.search-list > li { border-radius: var(--k-r-sm); box-shadow: var(--k-drop-sm); transition: transform .1s, box-shadow .1s; }
@media (hover: hover) { .search-list > li:hover { transform: translate(-2px, -2px); box-shadow: var(--k-drop-md); } }
.search-list > li:active { transform: translate(2px, 2px); box-shadow: none; }
.search-list a { display: block; padding: 12px 16px; color: var(--k-text); border-radius: calc(var(--k-r-sm) - 2px); }
.search-list a:hover { text-decoration: none; background: var(--k-inset); }
.search-list .snip { display: block; color: var(--k-muted); font-size: .9rem; margin-top: 4px; }

.toast { position: fixed; bottom: 22px; left: 50%; transform: translateX(-50%) translateY(30px); opacity: 0; z-index: 50; pointer-events: none; padding: 8px 18px 9px; text-align: center;
  background: var(--k-coin); color: var(--k-on-accent); border: 2px solid var(--k-black); border-radius: var(--k-r-sm); box-shadow: 4px 4px 0 var(--k-black); font: 400 1.25rem/1.2 var(--k-display); letter-spacing: .03em; transition: all .25s; }
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ----- Responsive ----- */
@media (max-width: 960px) {
  .menu-btn { display: inline-flex; }
  .sidebar { position: fixed; left: 0; top: var(--top-h); z-index: 20; transform: translateX(-105%); transition: transform .2s; box-shadow: 6px 0 0 var(--k-drop); }
  body.menu-open .sidebar { transform: none; }
  .dash { grid-template-columns: 1fr; }
  .py-status { display: none; }
}
@media (max-width: 640px) {
  body { font-size: 16px; }
  .brand span:last-child { display: none; }
  .brand-logo { height: 36px; padding: 0 6px; font-size: 1rem; letter-spacing: .04em; }
  .search-wrap { margin-left: 0; }
  .content { padding: 24px 14px 60px; }
  h1 { font-size: 2.2rem; }
  h2 { font-size: 1.8rem; }
  .lvl-row { grid-template-columns: 110px 1fr 44px; }
  .pager { grid-template-columns: 1fr; }
  .cheat-grid { grid-template-columns: 1fr; }
  .lesson-head .meta .act-done { margin-left: 0; }
  .hint { display: none; }
  .lesson-list a { gap: 10px; padding: 10px; flex-wrap: wrap; }
  .ll-body { flex-basis: calc(100% - 60px); }
  .ll-min { margin-left: 50px; }
  .exercise { padding: 0 12px 14px; }
  .ex-head { margin: 0 -12px 10px; padding: 8px 12px 9px; }
  .quiz { padding: 2px 12px 14px; }
  .callout { padding-right: 12px; }
  .codeblock, .shell { box-shadow: var(--k-drop-sm); }
  .cb-tools { padding: 8px 10px 10px; }
  .prog-level { padding: 0 12px 14px; }
  .prog-level-head { margin: 0 -12px 12px; padding: 8px 12px 9px; }
  .prog-summary { padding: 14px; }
  .search-page-form { flex-wrap: wrap; }
  /* the save-file table must fit a 344px cover screen without clipping its last column */
  .prog-table { table-layout: fixed; font-size: .86rem; }
  .prog-table th, .prog-table td { padding: 7px 5px; }
  .prog-table th { font-size: 1.05rem; overflow-wrap: normal; }
  .prog-table td:first-child, .prog-table th:first-child { width: 38px; }
  .prog-table th:nth-child(3) { width: 85px; }
  .prog-table th:nth-child(4) { width: 44px; }
  .prog-table td:nth-child(2) { overflow-wrap: anywhere; }
  th, td { padding: 7px 9px; }
}
@media (prefers-reduced-motion: reduce) {
  .py-status::before { animation: none; }
  .level-card:hover, .lesson-list > li:hover, .search-list > li:hover, .pager a:hover { transform: none; }
}
@media print {
  /* paper: black ink on white in BOTH themes (the dark theme's canvas, cream outlines and phosphor text must not reach the printer) */
  :root, [data-theme] { color-scheme: light; }
  html, body { background: white !important; color: var(--k-black); }
  .topbar, .sidebar, .scrim, .cb-tools, .pager, .lesson-done, .toast, .skip-link { display: none; }
  .layout { display: block; min-height: 0; }
  .content { max-width: none; padding: 0; }
  .content, .content * { color: var(--k-black) !important; background: none !important; border-color: var(--k-black) !important; box-shadow: none !important; text-shadow: none !important; }
  .editor-host::after { display: none; }
  .content .callout-title { background: white !important; }
  .output::before { color: var(--k-black); }
  .pbar > span { background: var(--k-black) !important; }
  .opt input::before { background: var(--k-black); }
  .callout { border-left-width: 8px; }
  .lesson-body > h2::before, .exercises > h2::before, .quiz-wrap > h2::before, .callout-title, .qn { box-shadow: none; }
  .card, .codeblock, .shell, .callout, .lesson-head, .table-wrap, .q { break-inside: avoid; }
  h1, h2, h3 { break-after: avoid; }
}