/* © 2026 Created with ♥ by Alex Munteanu | alexmunteanu.com */
/* The Agile Course - Folio surface layer. Base elements, chrome and shared
   components live in ../assets/theme/folio.css; this file owns only the course
   reading layout (sidebar nav, progress, level filter, in-course search, TOC,
   reading column, home, practice). It consumes Folio tokens via var(--…) and
   never re-declares a palette value. Load order: tokens.css -> folio.css -> this. */

/* ---------- Layout constants ----------
   Colors come straight from the Folio tokens (var(--color-*), var(--radius-md),
   var(--shadow-lg)) - this file re-declares no palette value. Only the course's
   own layout dimensions live here. --text-faint aliases the Folio faint ink for
   the one app.js render site that reads it. */
:root {
  --text-faint: var(--color-text-faint);
  --radius: var(--radius-md);
  --topbar-h: 58px;
  --sidebar-w: 300px;
  --toc-w: 220px;
  --maxw: var(--reading-wide);
}

/* ---------- Top bar (folio owns the chrome; this fixes height for the sticky rails) ---------- */
.topbar { height: var(--topbar-h); padding: 0 var(--page-pad); }

.topbar-search { position: relative; flex: 1; max-width: 460px; margin: 0 auto 0 6px; }
.search-results {
  position: absolute; top: 46px; left: 0; right: 0; z-index: 120;
  background: var(--color-bg); border: 1px solid var(--color-border); border-radius: var(--radius);
  box-shadow: var(--shadow-lg); max-height: min(70vh, 520px); overflow-y: auto; padding: 6px;
}
.search-results .sr-item { display: block; padding: 9px 12px; border-radius: var(--radius-sm); color: var(--color-text); }
.search-results .sr-item:hover, .search-results .sr-item.active { background: var(--color-surface); text-decoration: none; }
.search-results .sr-item .sr-crumb { display: block; font-family: var(--font-mono); font-size: 11px; letter-spacing: .04em; color: var(--color-text-faint); }
.search-results .sr-item .sr-title { font-weight: 600; }
.search-results .sr-item mark { background: var(--color-brand-soft); color: inherit; border-radius: 3px; }
.search-results .sr-empty { padding: 14px; color: var(--color-text-faint); text-align: center; }

.topbar-actions { display: flex; align-items: center; gap: 10px; }
/* Custom level filter: a button trigger + a Folio-tokenized listbox popup, so the
   OPEN menu is themed dark/light on-brand with a MINT selection accent (a native
   <select> popup ignores color-scheme and paints an OS-white box). Mirrors the
   .search-results dropdown language. The chevron is a token-tinted CSS-mask glyph
   (no hardcoded palette hex), so it reads on both themes. */
.level-select { position: relative; }
.level-trigger {
  display: inline-flex; align-items: center; height: 36px; padding: 0 30px 0 12px;
  border-radius: var(--radius-sm); border: 1px solid var(--color-border-strong);
  background: transparent; color: var(--color-text-muted);
  font-family: var(--font-mono); font-size: 12px; letter-spacing: .02em; cursor: pointer;
}
.level-trigger::after {
  content: ""; position: absolute; right: 11px; top: 50%;
  width: 12px; height: 12px; transform: translateY(-50%);
  pointer-events: none; background-color: var(--color-text-muted);
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='3'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E") no-repeat center / 12px 12px;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='3'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E") no-repeat center / 12px 12px;
  transition: transform var(--dur-fast) var(--ease-out);
}
.level-trigger[aria-expanded="true"]::after { transform: translateY(-50%) rotate(180deg); }
.level-trigger:hover { border-color: var(--color-brand); color: var(--color-text); }
.level-trigger:focus-visible { outline: none; border-color: var(--color-brand); box-shadow: 0 0 0 3px var(--color-brand-soft); }

.level-options {
  position: absolute; top: calc(100% + 6px); right: 0; z-index: 120; min-width: 100%;
  margin: 0; padding: 6px; list-style: none;
  background: var(--color-bg); border: 1px solid var(--color-border);
  border-radius: var(--radius); box-shadow: var(--shadow-lg);
}
.level-options[hidden] { display: none; }
.level-options:focus { outline: none; }
.level-option {
  position: relative; display: flex; align-items: center;
  padding: 8px 14px 8px 28px; border-radius: var(--radius-sm);
  font-family: var(--font-mono); font-size: 12px; letter-spacing: .02em;
  color: var(--color-text); white-space: nowrap; cursor: pointer; user-select: none;
}
.level-option:hover, .level-option.active { background: var(--color-surface); }
.level-option.active { box-shadow: inset 0 0 0 1px var(--color-brand-soft); }
.level-option[aria-selected="true"] { color: var(--color-accent); }
.level-option[aria-selected="true"]::before {
  content: "✓"; position: absolute; left: 11px; top: 50%; transform: translateY(-50%);
  font-size: 11px; color: var(--color-accent);
}

.nav-toggle { display: none; }
.burger, .burger::before, .burger::after {
  content: ""; display: block; width: 18px; height: 1.5px; background: currentColor; border-radius: 2px;
  transition: transform .2s;
}
.burger { position: relative; }
.burger::before { position: absolute; top: -6px; }
.burger::after { position: absolute; top: 6px; }

/* ---------- Layout ---------- */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--toc-w);
  align-items: start;
}

/* ---------- Sidebar ---------- */
.sidebar {
  position: sticky; top: var(--topbar-h);
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto;
  padding: 18px 14px 40px;
  border-right: 1px solid var(--color-border);
}
.sidebar.grab-scrolling { cursor: grabbing; user-select: none; }
.progress-wrap {
  padding: 14px 14px 16px; margin: 0 4px 16px; border-radius: var(--radius);
  background: var(--color-surface); border: 1px solid var(--color-border); position: relative;
}
.progress-head {
  display: flex; justify-content: space-between; margin-bottom: 10px;
  font-family: var(--font-mono); font-size: 11px; letter-spacing: var(--tracking-eyebrow);
  text-transform: uppercase; color: var(--color-text-faint);
}
#progressPct { color: var(--color-accent); }
.reset-progress {
  position: absolute; top: 12px; right: 12px; font-family: var(--font-mono); font-size: 10.5px;
  letter-spacing: .06em; text-transform: uppercase; color: var(--color-text-faint);
  background: none; border: none; cursor: pointer; padding: 2px 4px; opacity: 0; transition: opacity var(--dur-fast);
}
.progress-wrap:hover .reset-progress, .reset-progress:focus-visible { opacity: 1; }
.reset-progress:hover { color: var(--color-text); text-decoration: underline; }

.nav-module { margin-bottom: 2px; }
.nav-module-btn {
  display: flex; align-items: center; gap: 9px; width: 100%;
  padding: 8px 8px; border: none; background: none; cursor: pointer;
  font-family: var(--font-mono); font-size: 10.5px; font-weight: 500;
  letter-spacing: var(--tracking-eyebrow); text-transform: uppercase;
  color: var(--color-text-ghost); text-align: left; border-radius: var(--radius-sm);
  transition: color var(--dur-fast) var(--ease-out);
}
.nav-module-btn:hover { color: var(--color-text-muted); }
.nav-module-btn .mod-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nav-module-btn .chev { margin-left: auto; transition: transform .2s; font-size: 9px; }
.nav-module.collapsed .chev { transform: rotate(-90deg); }
.nav-lessons { list-style: none; margin: 0 0 10px; padding: 0; overflow: hidden; }
.nav-module.collapsed .nav-lessons { display: none; }
.nav-lessons a {
  display: flex; align-items: center; gap: 8px;
  padding: 7px 10px; border-radius: var(--radius-sm);
  color: var(--color-text-faint); font-size: 13.5px;
  transition: color var(--dur-fast) var(--ease-out);
}
.nav-lessons a:hover { color: var(--color-text); text-decoration: none; }
.nav-lessons a.active { color: var(--color-text); font-weight: 600; }
.nav-lessons a.done .check { color: var(--color-accent); }
.nav-lessons a .check { font-family: var(--font-mono); font-size: 12px; color: transparent; flex-shrink: 0; }
.nav-lessons a.done .lesson-name { color: var(--color-text-ghost); }
.nav-lessons a .lesson-name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.nav-section-label {
  font-family: var(--font-mono); font-size: 10.5px; text-transform: uppercase;
  letter-spacing: var(--tracking-eyebrow); color: var(--color-text-ghost);
  padding: 16px 8px 6px; font-weight: 500;
}

/* Level filter: dim non-matching lessons in place, never remove them */
.nav-lessons a.lv-dim { opacity: .45; }
.nav-lessons a.lv-dim:hover { opacity: 1; }
.nav-lessons a.lv-dim .lesson-name { color: var(--color-text-faint); }
.nav-lv {
  margin-left: auto; flex-shrink: 0; font-family: var(--font-mono); font-size: 10px;
  letter-spacing: .04em; color: var(--color-text-faint); text-transform: uppercase;
}
.filter-note {
  margin: 0 4px 14px; padding: 10px 12px; font-size: 12.5px; line-height: 1.5;
  color: var(--color-text-muted); background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}
.filter-note strong { color: var(--color-text); }
.filter-note a { font-weight: 600; color: var(--color-text-muted); text-decoration: underline; }
.filter-note a:hover { color: var(--color-text); }

/* ---------- Content ---------- */
.content { min-width: 0; padding: 0 44px; }
.lesson { position: relative; max-width: var(--maxw); margin: 0 auto; padding: 48px 0 8px; }
.lesson:focus { outline: none; }
.lesson-footer { max-width: var(--maxw); margin: 0 auto; }

/* Ghost numeral bleeding off the reading column's top-right edge */
.lesson-ghost { position: absolute; top: -8px; right: -6px; font-size: clamp(90px, 20vw, 200px); z-index: 0; }
.lesson-meta, .lesson > h1 { position: relative; z-index: 1; }

/* breadcrumb + level badge row */
.lesson-meta {
  display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; margin-bottom: 12px;
  font-family: var(--font-mono); font-size: 11px; letter-spacing: var(--tracking-eyebrow);
  text-transform: uppercase; color: var(--color-text-faint);
}
.lesson-crumb { color: var(--color-text-faint); }
.beyond-badge {
  font-family: var(--font-mono); font-size: 10.5px; letter-spacing: var(--tracking-eyebrow);
  text-transform: uppercase; color: var(--color-accent);
}

/* Typography inside lessons */
.lesson h1 { font-size: var(--text-page-title); line-height: 1.05; letter-spacing: var(--tracking-heading); margin: .1em 0 .5em; max-width: 16ch; }
.lesson h2 { font-size: var(--text-28); margin: 1.8em 0 .6em; scroll-margin-top: calc(var(--topbar-h) + 12px); }
.lesson h3 { font-size: var(--text-19); margin: 1.6em 0 .5em; scroll-margin-top: calc(var(--topbar-h) + 12px); }
.lesson h2 + h3 { margin-top: .8em; }
.lesson p { margin: 1em 0; color: var(--color-text-muted); }
.lesson ul, .lesson ol { margin: .9em 0; padding-left: 1.4em; color: var(--color-text-muted); }
.lesson li { margin: .4em 0; }
.lesson li::marker { color: var(--color-text-ghost); }
.lead { font-size: var(--text-19); color: var(--color-text-muted); line-height: 1.6; }
.lesson strong { color: var(--color-text); font-weight: 600; }
.lesson a { color: var(--color-text); text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--color-border-strong); }
.lesson a:hover { text-decoration-color: var(--color-brand); }
.lesson blockquote {
  margin: 1.4em 0; padding: .2em 0 .2em 1.1em; border-left: 2px solid var(--color-accent);
  color: var(--color-text); font-family: var(--font-display); font-size: 1.15rem;
}
.lesson blockquote p { margin: .4em 0; color: var(--color-text); }
.lesson hr { border: none; border-top: 1px solid var(--color-border); margin: 2.4em 0; }

/* Inline code + code blocks */
.lesson :not(pre) > code {
  font-family: var(--font-mono); font-size: .85em;
  background: var(--color-surface); padding: .12em .4em; border-radius: 5px;
  border: 1px solid var(--color-border); color: var(--color-text);
}
.codewrap { position: relative; margin: 1.4em 0; }
.lesson pre {
  margin: 0; padding: 18px 20px; overflow-x: auto;
  background: var(--color-surface); color: var(--color-text-muted);
  border-radius: var(--radius); border: 1px solid var(--color-border);
  font-size: 13px; line-height: 1.6;
}
.lesson pre code { font-family: var(--font-mono); background: none; border: none; padding: 0; color: inherit; }
.copy-btn {
  position: absolute; top: 8px; right: 8px; font-family: var(--font-mono); font-size: 10.5px;
  letter-spacing: .04em; text-transform: uppercase; color: var(--color-text-faint);
  background: var(--color-bg); border: 1px solid var(--color-border);
  padding: 4px 9px; border-radius: 6px; cursor: pointer; opacity: 0; transition: opacity var(--dur-fast), color var(--dur-fast);
}
.codewrap:hover .copy-btn { opacity: 1; }
.copy-btn:hover { color: var(--color-text); }
.copy-btn.copied { color: var(--color-accent); }

/* Tables */
.lesson .table-wrap { overflow-x: auto; margin: 1.4em 0; border: 1px solid var(--color-border); border-radius: var(--radius); }
.lesson table { border-collapse: collapse; width: 100%; font-size: 14px; }
.lesson th, .lesson td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--color-border); vertical-align: top; color: var(--color-text-muted); }
.lesson thead th {
  background: var(--color-surface); color: var(--color-text-faint); white-space: nowrap;
  font-family: var(--font-mono); font-size: 11px; letter-spacing: var(--tracking-eyebrow); text-transform: uppercase; font-weight: 500;
}
.lesson tbody tr:last-child td { border-bottom: none; }
.lesson tbody tr:hover td { background: var(--color-surface); }

/* Key-terms, checklists, pills */
.keybox {
  margin: 1.4em 0; padding: 4px 18px; border: 1px solid var(--color-border);
  border-radius: var(--radius); background: var(--color-surface);
}
.checklist { list-style: none; padding-left: 0; }
.checklist li { position: relative; padding-left: 28px; }
.checklist li::before {
  content: "\2713"; position: absolute; left: 4px; top: 1px; color: var(--color-accent); font-weight: 700;
}
.pill {
  display: inline-block; font-family: var(--font-mono); font-size: 11px; letter-spacing: .03em;
  text-transform: uppercase; padding: 2px 9px; border-radius: var(--radius-pill);
  border: 1px solid var(--color-border); color: var(--color-text-muted); margin: 2px 3px 2px 0;
}

/* Home / hero */
.hero { padding: 8px 0 14px; }
.hero h1 { font-size: var(--text-hero); margin: 0 0 .2em; }
.hero p { font-size: var(--text-19); color: var(--color-text-muted); max-width: 46ch; margin: .4em 0 1em; }
.path-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 0 40px; margin: 22px 0; }
.path-card {
  display: block; padding: 24px 0 26px; border-bottom: 1px solid var(--color-border);
  color: var(--color-text-muted); transition: color var(--dur-fast) var(--ease-out);
}
.path-card:hover { color: var(--color-text); text-decoration: none; }
.path-card h3 { margin: 0 0 6px; font-size: var(--text-22); color: inherit; }
.path-card p { font-size: 13.5px; color: var(--color-text-faint); margin: 0; line-height: 1.6; }
.path-card .pc-tag {
  display: inline-block; margin-top: 12px; font-family: var(--font-mono); font-size: 11px;
  letter-spacing: .04em; text-transform: uppercase; color: var(--color-accent);
}
.module-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 0 40px; margin: 18px 0; }
.mod-card { padding: 22px 0 24px; border-bottom: 1px solid var(--color-border); }
.mod-card h3 { margin: 0 0 8px; font-size: var(--text-19); }
.mod-card p { font-size: 13.5px; color: var(--color-text-faint); margin: 0 0 12px; }
.mod-card ol { margin: 0; padding-left: 1.2em; font-size: 13px; color: var(--color-text-faint); }
.mod-card ol a { color: var(--color-text-muted); text-decoration: none; }
.mod-card ol a:hover { color: var(--color-text); text-decoration: underline; }

/* Prev / next */
.prevnext { display: flex; gap: 24px; margin: 30px 0 10px; }
.prevnext a {
  flex: 1; padding: 18px 0 0; border-top: 1px solid var(--color-border);
  color: var(--color-text-muted); transition: color var(--dur-fast) var(--ease-out);
}
.prevnext a:hover { color: var(--color-text); text-decoration: none; }
.prevnext a.next { text-align: right; }
.prevnext .pn-label { font-family: var(--font-mono); font-size: 11px; letter-spacing: .04em; text-transform: uppercase; color: var(--color-text-faint); }
.prevnext .pn-title { font-family: var(--font-display); font-weight: 600; margin-top: 4px; }
.prevnext a.next .pn-title { color: var(--color-brand); }

.mark-done-bar { display: flex; align-items: center; gap: 12px; margin-top: 40px; padding-top: 22px; border-top: 1px solid var(--color-border); flex-wrap: wrap; }
.btn.done-state { background: transparent; color: var(--color-accent); border-color: var(--color-border-strong); }
.btn.done-state:hover { filter: none; color: var(--color-accent); border-color: var(--color-accent); }

/* ---------- On this page (TOC) ---------- */
.toc {
  position: sticky; top: var(--topbar-h);
  height: calc(100vh - var(--topbar-h)); overflow-y: auto;
  padding: 48px 18px 40px 4px; font-size: 13px;
}
.toc-title { font-family: var(--font-mono); text-transform: uppercase; font-size: 10.5px; letter-spacing: var(--tracking-eyebrow); color: var(--color-text-ghost); margin-bottom: 12px; }
.toc ul { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--color-border); }
.toc li a { display: block; padding: 5px 0 5px 14px; color: var(--color-text-faint); margin-left: -1px; border-left: 1px solid transparent; transition: color var(--dur-fast) var(--ease-out); }
.toc li a:hover { color: var(--color-text); text-decoration: none; }
.toc li a.active { color: var(--color-text); border-left-color: var(--color-brand); }
.toc li.h3 a { padding-left: 26px; font-size: 12.5px; }

/* ---------- Footer (folio owns .site-footer chrome) ---------- */
.site-footer { max-width: var(--maxw); margin: 96px auto 0; padding: 28px 0 60px; justify-content: center; text-align: center; }

/* ---------- Scrim (mobile) ---------- */
.scrim { display: none; }

/* ---------- Responsive ---------- */
@media (max-width: 1180px) {
  .layout { grid-template-columns: var(--sidebar-w) minmax(0,1fr); }
  .toc { display: none; }
}
@media (max-width: 860px) {
  :root { --topbar-h: 54px; }
  .layout { grid-template-columns: 1fr; }
  .nav-toggle { display: inline-flex; }
  .brand-text { display: none; }
  .topbar-search { margin-left: 0; }
  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; z-index: 90;
    width: min(86vw, 320px); height: calc(100vh - var(--topbar-h));
    background: var(--color-bg); border-right: 1px solid var(--color-border);
    transform: translateX(-102%); transition: transform .22s ease; box-shadow: var(--shadow-lg);
  }
  body.nav-open .sidebar { transform: translateX(0); }
  body.nav-open .scrim {
    display: block; position: fixed; inset: var(--topbar-h) 0 0 0; z-index: 80;
    background: rgba(0,0,0,.5);
  }
  .content { padding: 0 20px; }
  .lesson { padding-top: 30px; }
  .lesson-ghost { font-size: clamp(70px, 26vw, 130px); }
  .prevnext { flex-direction: column; gap: 0; }
  .prevnext a.next { text-align: left; }
}
@media (max-width: 480px) {
  .level-select { display: none; }
}

/* ---------- Practice layer (quiz / exercises / templates) ---------- */
.quiz-score {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius-sm); padding: 10px 14px; margin: 10px 0 18px;
  font-family: var(--font-mono); font-size: 12.5px; color: var(--color-text-muted);
}
.quiz-q {
  border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 14px 16px 12px; margin: 0 0 18px; background: var(--color-surface);
}
.quiz-q legend { font-weight: 600; padding: 0 6px; color: var(--color-text); }
.quiz-option {
  display: flex; align-items: baseline; gap: 10px;
  padding: 8px 10px; margin: 6px 0; border: 1px solid var(--color-border);
  border-radius: var(--radius-sm); cursor: pointer; background: transparent;
}
.quiz-option:hover { border-color: var(--color-border-strong); }
.quiz-option input { margin: 0; flex: none; accent-color: var(--color-brand); }
.quiz-option input:focus-visible { outline: 2px solid var(--color-brand); outline-offset: 2px; }
.quiz-option-text { flex: 1; color: var(--color-text-muted); }
.quiz-mark { flex: none; font-family: var(--font-mono); font-size: 12px; white-space: nowrap; }
.quiz-option.correct { border-color: var(--color-accent); }
.quiz-option.correct .quiz-mark { color: var(--color-accent); }
.quiz-option.incorrect { border-color: var(--color-border-strong); }
.quiz-option.incorrect .quiz-mark { color: var(--color-text-muted); }
.quiz-explain {
  margin-top: 10px; padding: 10px 12px; font-size: 14px; color: var(--color-text-muted);
  background: var(--callout-bg); border-left: 2px solid var(--color-accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.quiz-reset { margin: 4px 0 8px; }
.exercise {
  border: 1px solid var(--color-border); border-left: 2px solid var(--color-accent);
  border-radius: var(--radius-sm); padding: 12px 16px; margin: 0 0 16px;
  background: var(--color-surface);
}
.exercise-model { margin-top: 12px; padding-top: 10px; border-top: 1px solid var(--color-border); }
.exercise-model-label { font-family: var(--font-mono); font-size: 11px; letter-spacing: var(--tracking-eyebrow); text-transform: uppercase; color: var(--color-text-faint); margin-bottom: 6px; }
.exercise-reveal { margin-top: 4px; }
.tpl-block { margin: 0 0 18px; }
.tpl-head { display: flex; align-items: center; gap: 10px; margin-bottom: 6px; }
.tpl-lang { font-family: var(--font-mono); font-size: 11px; color: var(--color-text-faint); border: 1px solid var(--color-border); border-radius: var(--radius-pill); padding: 1px 8px; }
.download-btn { right: 70px; }

/* ---------- Print ---------- */
@media print {
  .topbar, .sidebar, .toc, .prevnext, .mark-done-bar, .scrim, .site-footer .credit, .lesson-ghost { display: none !important; }
  .quiz-reset, .exercise-reveal, .copy-btn, .download-btn, .quiz-score { display: none !important; }
  .quiz-option.correct, .quiz-option.incorrect { border-color: #ccc !important; }
  .quiz-mark { display: none !important; }
  .quiz-explain[hidden], .exercise-model[hidden] { display: none !important; }
  .tpl-block pre { white-space: pre-wrap; word-break: break-word; }
  .layout { display: block; }
  .content { padding: 0; }
  .lesson { max-width: 100%; }
  .lesson pre { background: #f4f4f4 !important; color: #111 !important; border: 1px solid #ccc; }
  a { color: inherit; text-decoration: underline; }
}