:root {
  --teko-pink: #e6116a;
  --teko-pink-dark: #b80e55;
  --teko-navy: #262f45;
  --teko-navy-2: #35405b;
  --ink: #1c2333;
  --muted: #667085;
  --paper: #ffffff;
  --canvas: #f4f3f6;
  --line: #dddbe2;
  --good: #18855b;
  --warn: #a86409;
  --danger: #b42318;
  --shadow: 0 18px 50px rgba(38, 47, 69, 0.10);
  --radius: 18px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--canvas);
  font: 16px/1.55 Arial, Helvetica, sans-serif;
}
a { color: inherit; }
button, input, textarea, select { font: inherit; }
button { cursor: pointer; }
:focus-visible { outline: 3px solid rgba(230, 17, 106, .35); outline-offset: 3px; }

.skip-link {
  position: fixed; left: 1rem; top: -4rem; z-index: 100;
  background: var(--paper); padding: .7rem 1rem; border-radius: 10px;
}
.skip-link:focus { top: 1rem; }

.topbar {
  position: sticky; top: 0; z-index: 40;
  min-height: 78px; display: flex; align-items: center; gap: 1.5rem;
  padding: .75rem clamp(1rem, 3vw, 3rem);
  background: rgba(255,255,255,.96); border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}
.brand { display: inline-flex; align-items: center; gap: 1rem; text-decoration: none; }
.brand img { width: 126px; height: auto; }
.brand-text { border-left: 1px solid var(--line); padding-left: 1rem; }
.brand-text strong { display: block; font-size: .95rem; }
.brand-text span { display: block; color: var(--muted); font-size: .78rem; }
.top-actions { margin-left: auto; display: flex; gap: .6rem; }

.btn {
  border: 1px solid var(--line); background: var(--paper); color: var(--teko-navy);
  border-radius: 999px; padding: .62rem .9rem; font-weight: 700; text-decoration: none;
  display: inline-flex; align-items: center; justify-content: center; gap: .45rem;
}
.btn:hover { border-color: var(--teko-pink); color: var(--teko-pink-dark); }
.btn-primary { background: var(--teko-pink); color: white; border-color: var(--teko-pink); }
.btn-primary:hover { background: var(--teko-pink-dark); color: white; }
.btn-small { padding: .45rem .72rem; font-size: .85rem; }

.shell { display: grid; grid-template-columns: 270px minmax(0, 1fr); min-height: calc(100vh - 78px); }
.sidebar {
  position: sticky; top: 78px; align-self: start; height: calc(100vh - 78px); overflow: auto;
  background: var(--teko-navy); color: #fff; padding: 1.6rem 1.25rem;
}
.sidebar-label { color: #b9c0d2; font-size: .72rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; margin: 1.2rem .55rem .55rem; }
.sidebar nav { display: grid; gap: .35rem; }
.sidebar a {
  display: flex; align-items: center; gap: .7rem; padding: .7rem .75rem;
  border-radius: 11px; color: #f6f7fb; text-decoration: none; font-weight: 700; font-size: .92rem;
}
.sidebar a:hover, .sidebar a[aria-current="page"] { background: rgba(255,255,255,.12); }
.sidebar a[aria-current="page"] { box-shadow: inset 3px 0 var(--teko-pink); }
.nav-number {
  width: 1.8rem; height: 1.8rem; flex: 0 0 auto; display: grid; place-items: center;
  border-radius: 50%; background: rgba(255,255,255,.1); font-size: .75rem;
}
.sidebar-progress { margin-top: 1.5rem; padding: 1rem; border: 1px solid rgba(255,255,255,.15); border-radius: 14px; }
.progress-track { height: 8px; background: rgba(255,255,255,.17); border-radius: 99px; overflow: hidden; }
.progress-fill { height: 100%; width: 0; background: var(--teko-pink); transition: width .25s ease; }
.progress-label { display: flex; justify-content: space-between; gap: .5rem; margin-top: .55rem; font-size: .78rem; color: #d4d8e2; }

.main { width: min(1180px, 100%); margin: 0 auto; padding: clamp(1.25rem, 4vw, 4rem); }
.hero {
  position: relative; overflow: hidden; min-height: 370px; display: grid; align-items: end;
  color: #fff; background: var(--teko-navy); border-radius: 28px; padding: clamp(2rem, 6vw, 5rem);
  box-shadow: var(--shadow);
}
.hero::before {
  content: ""; position: absolute; width: 440px; height: 440px; right: -120px; top: -160px;
  border: 78px solid var(--teko-pink); border-radius: 50%; opacity: .92;
}
.hero::after {
  content: ""; position: absolute; width: 260px; height: 260px; right: 120px; bottom: -170px;
  border: 32px solid rgba(255,255,255,.12); transform: rotate(45deg);
}
.hero-content { position: relative; z-index: 1; max-width: 760px; }
.eyebrow { margin: 0 0 .8rem; color: var(--teko-pink); font-size: .82rem; font-weight: 900; letter-spacing: .13em; text-transform: uppercase; }
.hero .eyebrow { color: #ff80b4; }
h1, h2, h3 { color: var(--teko-navy); line-height: 1.12; }
.hero h1 { margin: 0; color: #fff; font-size: clamp(2.4rem, 6vw, 5.4rem); letter-spacing: -.045em; }
.hero p { max-width: 650px; margin: 1.15rem 0 0; color: #dfe3ec; font-size: clamp(1rem, 2vw, 1.24rem); }
.hero-actions { display: flex; flex-wrap: wrap; gap: .7rem; margin-top: 1.6rem; }
.hero-meta { display: flex; flex-wrap: wrap; gap: 1rem; margin-top: 2rem; color: #c5cad7; font-size: .85rem; }

.page-head { padding: 2rem 0 1rem; }
.page-head h1 { margin: .25rem 0 .75rem; font-size: clamp(2.3rem, 5vw, 4.8rem); letter-spacing: -.045em; }
.lead { max-width: 800px; color: var(--muted); font-size: 1.14rem; }

.breadcrumbs {
  display: flex; flex-wrap: wrap; gap: .4rem; align-items: center;
  margin: 0 0 1.25rem; color: var(--muted); font-size: .82rem;
}
.breadcrumbs a { color: var(--teko-pink-dark); font-weight: 750; text-decoration: none; }
.breadcrumbs a:hover { text-decoration: underline; }
.reading-meta { display: flex; flex-wrap: wrap; gap: .55rem; margin-top: 1rem; }
.reading-meta span {
  border: 1px solid var(--line); border-radius: 999px; background: var(--paper);
  padding: .28rem .62rem; color: var(--muted); font-size: .78rem; font-weight: 750;
}

.section { margin-top: clamp(2.5rem, 6vw, 5rem); scroll-margin-top: 100px; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 1rem; margin-bottom: 1.25rem; }
.section-head h2 { margin: 0; font-size: clamp(1.7rem, 3vw, 2.7rem); letter-spacing: -.03em; }
.section-number { color: var(--teko-pink); font-weight: 900; font-size: .82rem; letter-spacing: .12em; text-transform: uppercase; }
.grid { display: grid; gap: 1rem; }
.grid-2 { grid-template-columns: repeat(2, minmax(0,1fr)); }
.grid-3 { grid-template-columns: repeat(3, minmax(0,1fr)); }
.grid-4 { grid-template-columns: repeat(4, minmax(0,1fr)); }
.grid-auto { grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); }

.card {
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.25rem; box-shadow: 0 10px 26px rgba(38,47,69,.05);
}
.card h3 { margin: 0 0 .6rem; font-size: 1.12rem; }
.card p { margin: .45rem 0; color: var(--muted); }
.card ul, .card ol { padding-left: 1.25rem; }
.card li + li { margin-top: .35rem; }
.card-accent { border-top: 5px solid var(--teko-pink); }
.lesson-card { display: flex; flex-direction: column; min-height: 250px; text-decoration: none; transition: transform .18s ease, box-shadow .18s ease; }
.lesson-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.lesson-card .lesson-index { color: var(--teko-pink); font-size: 2.8rem; font-weight: 900; line-height: 1; }
.lesson-card .lesson-link { margin-top: auto; padding-top: 1rem; color: var(--teko-pink-dark); font-weight: 800; }

.tag-row { display: flex; flex-wrap: wrap; gap: .45rem; margin-top: .8rem; }
.tag { display: inline-flex; align-items: center; border-radius: 999px; background: #f3e9ef; color: #8f1247; padding: .25rem .6rem; font-size: .74rem; font-weight: 800; }
.tag-navy { background: #e8eaf0; color: var(--teko-navy); }
.badge { display: inline-flex; align-items: center; padding: .25rem .55rem; border-radius: 7px; font-size: .72rem; font-weight: 900; text-transform: uppercase; letter-spacing: .05em; }
.badge-core { color: #0f6848; background: #dff5ec; }
.badge-plus { color: #315694; background: #e5edfb; }
.badge-challenge { color: #914c00; background: #fff1d6; }

.agenda { display: grid; grid-template-columns: repeat(4, 1fr); gap: .7rem; }
.agenda-step { background: var(--paper); border-radius: 14px; padding: 1rem; border: 1px solid var(--line); }
.agenda-step time { display: block; color: var(--teko-pink); font-weight: 900; font-size: .8rem; }
.agenda-step strong { display: block; margin-top: .35rem; color: var(--teko-navy); }

.system-map { display: grid; gap: .8rem; grid-template-columns: repeat(5, 1fr); align-items: center; }
.system-node { min-height: 112px; display: grid; place-items: center; text-align: center; padding: .9rem; background: var(--paper); border: 1px solid var(--line); border-radius: 16px; font-weight: 800; box-shadow: 0 8px 20px rgba(38,47,69,.05); }
.system-node strong { color: var(--teko-navy); }
.system-node small { color: var(--muted); }
.system-node.highlight { color: white; background: var(--teko-navy); border-color: var(--teko-navy); }
.system-node.highlight strong, .system-node.highlight small { color: white; }
.arrow { color: var(--teko-pink); font-size: 1.6rem; font-weight: 900; text-align: center; }

.theory-list details { background: var(--paper); border: 1px solid var(--line); border-radius: 14px; margin-bottom: .7rem; overflow: hidden; }
.theory-list summary { list-style: none; padding: 1rem 1.1rem; font-weight: 850; color: var(--teko-navy); cursor: pointer; }
.theory-list summary::-webkit-details-marker { display: none; }
.theory-list summary::after { content: "+"; float: right; color: var(--teko-pink); font-size: 1.3rem; }
.theory-list details[open] summary::after { content: "−"; }
.theory-body { padding: 0 1.1rem 1.2rem; color: var(--muted); }
.theory-body strong { color: var(--ink); }

.toc {
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.15rem 1.25rem; box-shadow: 0 8px 24px rgba(38,47,69,.04);
}
.toc strong { display: block; margin-bottom: .55rem; color: var(--teko-navy); }
.toc ol, .toc ul { margin: 0; padding-left: 1.25rem; columns: 2; column-gap: 2rem; }
.toc li { break-inside: avoid; margin: .28rem 0; }
.toc a { color: var(--teko-pink-dark); text-decoration-thickness: 1px; text-underline-offset: 2px; }

.prose { max-width: 900px; }
.prose h3 { margin-top: 1.8rem; font-size: 1.25rem; }
.prose h4 { margin: 1.35rem 0 .4rem; color: var(--teko-navy); font-size: 1rem; }
.prose p, .prose li { color: #475467; }
.prose li + li { margin-top: .38rem; }
.prose blockquote {
  margin: 1.2rem 0; border-left: 5px solid var(--teko-pink); border-radius: 0 12px 12px 0;
  background: #fff3f8; padding: .9rem 1.1rem; color: var(--teko-navy); font-weight: 750;
}

.diagram {
  margin: 1.25rem 0; overflow: hidden; background: var(--paper);
  border: 1px solid var(--line); border-radius: var(--radius); box-shadow: 0 10px 28px rgba(38,47,69,.05);
}
.diagram svg, .diagram img { display: block; width: 100%; height: auto; background: #faf9fb; }
.diagram figcaption { padding: .85rem 1rem; color: var(--muted); font-size: .86rem; border-top: 1px solid var(--line); }
.metaphor-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 1rem; }
.metaphor-box { border-radius: 14px; padding: 1rem; background: #eef3ff; border-left: 5px solid #4a67a1; }
.metaphor-box.limit { background: #fff7e8; border-color: var(--warn); }
.metaphor-box strong { display: block; margin-bottom: .3rem; color: var(--teko-navy); }

.decision-rule {
  margin: 1rem 0; border: 1px solid #acd9c7; border-radius: 14px;
  background: #effaf5; padding: 1rem 1.1rem; color: #155e45;
}
.decision-rule strong { color: #0d4c37; }
.warning {
  margin: 1rem 0; border: 1px solid #efc6c1; border-radius: 14px;
  background: #fff3f1; padding: 1rem 1.1rem; color: #7a271a;
}
.info-note {
  margin: 1rem 0; border-left: 5px solid #4a67a1; border-radius: 0 14px 14px 0;
  background: #eef3ff; padding: 1rem 1.1rem; color: #263f72;
}

.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 14px; background: var(--paper); }
.comparison { width: 100%; border-collapse: collapse; min-width: 620px; }
.comparison th, .comparison td { padding: .78rem .9rem; border-bottom: 1px solid var(--line); vertical-align: top; text-align: left; }
.comparison th { background: var(--teko-navy); color: white; }
.comparison tr:last-child td { border-bottom: 0; }
.comparison code { white-space: nowrap; }

.step-list { counter-reset: steps; display: grid; gap: .85rem; padding: 0; list-style: none; }
.step-list > li {
  counter-increment: steps; position: relative; min-height: 3.2rem; padding: .8rem 1rem .8rem 3.8rem;
  border: 1px solid var(--line); border-radius: 14px; background: var(--paper); color: var(--muted);
}
.step-list > li::before {
  content: counter(steps); position: absolute; left: .85rem; top: .7rem; width: 2.15rem; height: 2.15rem;
  display: grid; place-items: center; border-radius: 50%; background: var(--teko-pink); color: white; font-weight: 900;
}
.step-list strong { display: block; color: var(--teko-navy); }

.endpoint {
  display: grid; grid-template-columns: auto minmax(0,1fr) auto; gap: .75rem; align-items: center;
  margin: .65rem 0; padding: .8rem; border: 1px solid var(--line); border-radius: 12px; background: var(--paper);
}
.method { min-width: 3.8rem; text-align: center; border-radius: 7px; padding: .2rem .45rem; font-size: .72rem; font-weight: 900; }
.method-get { background: #e5edfb; color: #315694; }
.method-post { background: #dff5ec; color: #0f6848; }
.method-delete { background: #fff0ee; color: var(--danger); }
.endpoint code { overflow-wrap: anywhere; }
.endpoint small { color: var(--muted); }

.status-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px,1fr)); gap: .8rem; }
.status-card { border: 1px solid var(--line); border-radius: 14px; background: var(--paper); padding: 1rem; }
.status-card strong { display: block; color: var(--teko-navy); }
.status-value { margin-top: .35rem; color: var(--muted); font-family: ui-monospace, monospace; }
.status-dot { display: inline-block; width: .65rem; height: .65rem; margin-right: .35rem; border-radius: 50%; background: #98a2b3; }
.status-dot.ok { background: var(--good); }
.status-dot.error { background: var(--danger); }
.lab-console { min-height: 150px; max-height: 430px; overflow: auto; white-space: pre-wrap; }
.button-row { display: flex; flex-wrap: wrap; gap: .65rem; align-items: center; }
.button-row .btn[disabled] { cursor: wait; opacity: .62; }

.exercise-list { display: grid; gap: 1rem; }
.exercise {
  position: relative; background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.25rem 1.25rem 1.25rem 4.2rem; box-shadow: 0 8px 24px rgba(38,47,69,.045);
}
.exercise.completed { border-color: rgba(24,133,91,.5); background: #f7fffb; }
.exercise-check { position: absolute; left: 1.25rem; top: 1.2rem; width: 2rem; height: 2rem; accent-color: var(--good); }
.exercise h3 { margin: 0; font-size: 1.12rem; }
.exercise-meta { display: flex; flex-wrap: wrap; align-items: center; gap: .5rem; margin-bottom: .45rem; }
.exercise ol, .exercise ul { padding-left: 1.2rem; }
.exercise details { margin-top: .8rem; border-top: 1px dashed var(--line); padding-top: .7rem; }
.exercise summary { cursor: pointer; color: var(--teko-pink-dark); font-weight: 800; }
.solution { display: none; margin-top: .7rem; padding: .8rem; border-left: 4px solid var(--good); background: #effaf5; color: #155e45; }
body.teacher-mode .solution { display: block; }
.teacher-only { display: none; }
body.teacher-mode .teacher-only { display: block; }

.discussion { background: var(--teko-navy); color: white; border-radius: 22px; padding: clamp(1.4rem,4vw,2.4rem); }
.discussion h2, .discussion h3 { color: white; }
.discussion ul { display: grid; gap: .8rem; padding-left: 1.2rem; }
.discussion li::marker { color: var(--teko-pink); }

pre, code, .code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
code { background: #eceaf0; border-radius: 5px; padding: .12rem .3rem; }
pre { position: relative; overflow: auto; background: #151b2a; color: #e9edf7; border-radius: 14px; padding: 1rem; font-size: .86rem; }
pre code { background: transparent; padding: 0; }
.copy-button { position: absolute; right: .6rem; top: .6rem; border: 1px solid #47516a; border-radius: 8px; background: #252e43; color: white; padding: .35rem .55rem; font-size: .72rem; }

.lab-panel { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.25rem; }
.field { display: grid; gap: .35rem; margin-bottom: .85rem; }
.field label { color: var(--teko-navy); font-size: .82rem; font-weight: 800; }
.field input, .field textarea, .field select { width: 100%; border: 1px solid #c9c7d0; border-radius: 10px; background: #fff; padding: .7rem .8rem; }
.field textarea { min-height: 150px; resize: vertical; font-family: ui-monospace, monospace; }
.result-box { min-height: 84px; margin-top: .8rem; border-radius: 12px; background: #f0eef2; padding: .85rem; white-space: pre-wrap; font-family: ui-monospace, monospace; font-size: .85rem; }
.result-box.ok { background: #e8f8f1; color: #116146; }
.result-box.error { background: #fff0ee; color: var(--danger); }

.quiz { display: grid; gap: .65rem; }
.quiz-option { text-align: left; border: 1px solid var(--line); border-radius: 12px; background: var(--paper); padding: .8rem 1rem; }
.quiz-option:hover { border-color: var(--teko-pink); }
.quiz-option.correct { border-color: var(--good); background: #eaf9f2; }
.quiz-option.incorrect { border-color: var(--danger); background: #fff0ee; }
.quiz-feedback { min-height: 1.5rem; color: var(--muted); font-weight: 700; }

.rubric { width: 100%; border-collapse: collapse; background: var(--paper); border-radius: 16px; overflow: hidden; }
.rubric th, .rubric td { padding: .85rem 1rem; border-bottom: 1px solid var(--line); text-align: left; }
.rubric th { background: var(--teko-navy); color: white; }
.rubric td:last-child, .rubric th:last-child { text-align: right; font-weight: 800; }
.rubric input[type="number"] { width: 76px; border: 1px solid #c9c7d0; border-radius: 8px; padding: .45rem; text-align: right; }
.rubric-total { margin-top: 1rem; display: flex; justify-content: flex-end; color: var(--teko-navy); font-size: 1.35rem; font-weight: 900; }
.assessment-meta { display: grid; grid-template-columns: repeat(3,1fr); gap: .8rem; margin: 1rem 0; }

.callout { display: flex; gap: 1rem; align-items: flex-start; padding: 1rem; border-radius: 14px; background: #fff3f8; border-left: 5px solid var(--teko-pink); }
.callout strong { color: var(--teko-navy); }
.callout-icon { color: var(--teko-pink); font-size: 1.35rem; line-height: 1; }

.footer { margin-top: 5rem; padding-top: 1.5rem; border-top: 1px solid var(--line); color: var(--muted); font-size: .78rem; display: flex; justify-content: space-between; gap: 1rem; }

.presentation-exit { display: none; position: fixed; right: 1rem; top: 1rem; z-index: 100; }
body.presentation-mode { background: var(--teko-navy); }
body.presentation-mode .topbar, body.presentation-mode .sidebar, body.presentation-mode .footer { display: none; }
body.presentation-mode .shell { display: block; }
body.presentation-mode .main { width: 100%; max-width: none; padding: 0; }
body.presentation-mode .presentation-exit { display: inline-flex; }
body.presentation-mode .section, body.presentation-mode .page-head {
  width: 100vw; min-height: 100vh; margin: 0; padding: 7vh 7vw; display: flex; flex-direction: column; justify-content: center;
  background: var(--canvas); border-bottom: 1px solid var(--line);
}
body.presentation-mode .page-head { background: var(--teko-navy); color: white; }
body.presentation-mode .page-head h1 { color: white; }
body.presentation-mode .exercise-list { grid-template-columns: repeat(2, minmax(0,1fr)); }

@media (max-width: 1050px) {
  .grid-4 { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .system-map { grid-template-columns: 1fr; }
  .arrow { transform: rotate(90deg); }
  .agenda { grid-template-columns: repeat(2,1fr); }
}
@media (max-width: 820px) {
  .shell { display: block; }
  .sidebar { position: static; height: auto; padding: .8rem 1rem; }
  .sidebar nav { display: flex; overflow-x: auto; padding-bottom: .3rem; }
  .sidebar-label, .sidebar-progress { display: none; }
  .sidebar a { white-space: nowrap; background: rgba(255,255,255,.07); }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .topbar { min-height: 68px; }
  .brand img { width: 104px; }
  .brand-text { display: none; }
  .top-actions .label { display: none; }
  .assessment-meta { grid-template-columns: 1fr; }
  .toc ol, .toc ul { columns: 1; }
  .metaphor-grid { grid-template-columns: 1fr; }
  .endpoint { grid-template-columns: auto 1fr; }
  .endpoint small { grid-column: 1 / -1; }
}
@media (max-width: 560px) {
  .main { padding: 1rem; }
  .hero { min-height: 430px; padding: 1.5rem; border-radius: 20px; }
  .hero::before { width: 320px; height: 320px; right: -160px; }
  .grid-4, .agenda { grid-template-columns: 1fr; }
  .exercise { padding-left: 1.1rem; padding-top: 4.1rem; }
  .exercise-check { left: 1.1rem; }
  .footer { flex-direction: column; }
}
@media print {
  .topbar, .sidebar, .top-actions, .presentation-exit, .exercise-check, .copy-button { display: none !important; }
  .shell { display: block; }
  .main { padding: 0; width: 100%; }
  .card, .exercise, .theory-list details { break-inside: avoid; box-shadow: none; }
  .solution { display: none !important; }
  body { background: white; }
}