/* Lesson page design reference for course packages. Tokens follow design/assets/ui.css. */
:root {
  --bg: #eef1f6;
  --surface: #ffffff;
  --surface-2: #f5f7fa;
  --surface-3: #e8edf4;
  --line: #d9e0ea;
  --line-strong: #bcc7d6;
  --text: #131a23;
  --text-2: #3b4756;
  --muted: #5f6b7a;
  --accent: #2266dd;
  --accent-bg: #e3ecfd;
  --ok: #1d8a58;
  --ok-bg: #e0f3e9;
  --warn: #9a6a08;
  --warn-bg: #fbf0d8;
  --danger: #c8372a;
  --danger-bg: #fbe6e3;
  --info: #1d6f8c;
  --info-bg: #e0f0f6;
  --violet: #6d4fd0;
  --violet-bg: #ece6fc;
  --code-bg: #f6f8fb;
  --code-hl: #fff4cc;
  --shadow: 0 1px 3px rgba(20, 30, 45, 0.08), 0 8px 24px rgba(20, 30, 45, 0.06);
  --radius: 14px;
  --radius-sm: 9px;
  --font:
    system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial,
    sans-serif;
  --mono: "JetBrains Mono", Consolas, ui-monospace, monospace;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1116;
    --surface: #141920;
    --surface-2: #1a212a;
    --surface-3: #212a35;
    --line: #263039;
    --line-strong: #35424f;
    --text: #e7ecf3;
    --text-2: #b9c4d1;
    --muted: #8c99a8;
    --accent: #5093ff;
    --accent-bg: #16294a;
    --ok: #46c68a;
    --ok-bg: #102d22;
    --warn: #e3a63c;
    --warn-bg: #32260f;
    --danger: #f0634f;
    --danger-bg: #3a1a16;
    --info: #5cb8db;
    --info-bg: #102a34;
    --violet: #a98bff;
    --violet-bg: #241d3d;
    --code-bg: #10151b;
    --code-hl: #33300f;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 8px 24px rgba(0, 0, 0, 0.3);
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #0e1116;
  --surface: #141920;
  --surface-2: #1a212a;
  --surface-3: #212a35;
  --line: #263039;
  --line-strong: #35424f;
  --text: #e7ecf3;
  --text-2: #b9c4d1;
  --muted: #8c99a8;
  --accent: #5093ff;
  --accent-bg: #16294a;
  --ok: #46c68a;
  --ok-bg: #102d22;
  --warn: #e3a63c;
  --warn-bg: #32260f;
  --danger: #f0634f;
  --danger-bg: #3a1a16;
  --info: #5cb8db;
  --info-bg: #102a34;
  --violet: #a98bff;
  --violet-bg: #241d3d;
  --code-bg: #10151b;
  --code-hl: #33300f;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 8px 24px rgba(0, 0, 0, 0.3);
  color-scheme: dark;
}

* {
  box-sizing: border-box;
}
html {
  scroll-padding-top: 76px;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px / 1.6 var(--font);
  -webkit-font-smoothing: antialiased;
}
a {
  color: var(--accent);
}
a:focus-visible,
button:focus-visible,
summary:focus-visible,
input:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
  border-radius: 6px;
}
svg.icon {
  width: 1.1em;
  height: 1.1em;
  flex: none;
  vertical-align: -0.18em;
}
code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--surface-3);
  padding: 0.1em 0.35em;
  border-radius: 5px;
}

/* Top bar */
.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 16px;
  height: 60px;
  padding: 0 20px;
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  white-space: nowrap;
}
.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 9px;
  background: var(--accent);
  color: #fff;
  display: grid;
  place-items: center;
}
.crumb {
  color: var(--muted);
  font-size: 15px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}
.topbar-spacer {
  flex: 1;
}
.audience {
  display: inline-flex;
  padding: 3px;
  border-radius: 999px;
  background: var(--surface-3);
}
.audience a {
  padding: 5px 14px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-2);
  text-decoration: none;
  white-space: nowrap;
}
.audience a[aria-current="page"] {
  background: var(--surface);
  color: var(--text);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12);
}
.kit-chip {
  font-size: 13px;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 4px 10px;
  white-space: nowrap;
}
.icon-btn {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text-2);
  border-radius: 10px;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  cursor: pointer;
}
.icon-btn:hover {
  background: var(--surface-2);
}
.menu-btn {
  display: none;
}

/* Layout */
.layout {
  display: grid;
  grid-template-columns: 272px minmax(0, 1fr) 248px;
  gap: 32px;
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 24px;
}
.sidebar,
.outline {
  position: sticky;
  top: 60px;
  align-self: start;
  max-height: calc(100vh - 60px);
  overflow: auto;
  padding: 24px 0 40px;
}
.main {
  padding: 32px 0 96px;
  min-width: 0;
}
.main-inner {
  max-width: 780px;
  margin: 0 auto;
}

.layout.no-outline {
  grid-template-columns: 272px minmax(0, 1fr);
}
.layout.no-outline .main-inner {
  max-width: 960px;
}

/* Course map */
.map-title {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 10px 10px;
}
.map-topic {
  margin: 0 0 14px;
}
.map-topic-name {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-2);
  margin: 0 10px 4px;
}
.map-lesson {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 7px 10px;
  border-radius: 9px;
  font-size: 15px;
  line-height: 1.35;
  color: var(--text);
  text-decoration: none;
}
.map-lesson:hover {
  background: var(--surface-3);
}
.map-lesson[aria-current="page"] {
  background: var(--accent-bg);
  color: var(--accent);
  font-weight: 600;
}
.map-lesson.is-outline {
  color: var(--muted);
}
.map-num {
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  color: var(--muted);
  min-width: 26px;
}
.map-soon {
  margin-left: auto;
  font-size: 11px;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0 7px;
  white-space: nowrap;
}

/* Outline */
.outline-title {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 12px;
}
.progress {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
  font-size: 14px;
  color: var(--text-2);
}
.progress-bar {
  flex: 1;
  height: 6px;
  border-radius: 999px;
  background: var(--surface-3);
  overflow: hidden;
}
.progress-bar span {
  display: block;
  height: 100%;
  width: 0;
  background: var(--ok);
  transition: width 0.3s;
}
.outline-session {
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  margin: 14px 0 6px;
}
.outline a {
  display: flex;
  gap: 8px;
  align-items: baseline;
  padding: 5px 8px;
  border-radius: 8px;
  font-size: 14px;
  line-height: 1.35;
  color: var(--text-2);
  text-decoration: none;
  border-left: 2px solid transparent;
}
.outline a:hover {
  background: var(--surface-3);
}
.outline a.is-active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: var(--accent-bg);
}
.outline a.is-done .o-num {
  background: var(--ok);
  color: #fff;
  border-color: var(--ok);
}
.o-num {
  flex: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 1.5px solid var(--line-strong);
  font-size: 11px;
  display: grid;
  place-items: center;
  font-weight: 600;
}

/* Hero */
.eyebrow {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 8px;
}
.eyebrow.teacher {
  color: var(--violet);
}
h1 {
  font-size: clamp(30px, 4vw, 40px);
  line-height: 1.15;
  margin: 0 0 12px;
  letter-spacing: -0.015em;
}
.subtitle {
  font-size: 19px;
  color: var(--text-2);
  margin: 0 0 18px;
}
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 24px;
}
.chip {
  display: inline-flex;
  gap: 6px;
  align-items: center;
  padding: 5px 12px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--line);
  font-size: 14px;
  color: var(--text-2);
}
.outcome {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 18px 20px;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--accent-bg), var(--surface));
  border: 1px solid var(--line);
  margin-bottom: 20px;
}
.outcome-icon {
  flex: none;
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: var(--accent);
  color: #fff;
  display: grid;
  place-items: center;
}
.main .outcome h2 {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  margin: 0 0 4px;
}
.outcome p {
  margin: 0;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(230px, 100%), 1fr));
  gap: 14px;
  margin: 0 0 28px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
}
.main .card h2 {
  display: flex;
  gap: 8px;
  align-items: center;
  font-size: 15px;
  margin: 0 0 10px;
}
.card p {
  font-size: 15px;
  color: var(--text-2);
}
.card ul {
  margin: 0;
  padding-left: 20px;
  font-size: 15px;
}
.card li + li {
  margin-top: 4px;
}
.card.wide {
  grid-column: 1 / -1;
}

/* Prose */
.main h2 {
  font-size: 24px;
  line-height: 1.25;
  margin: 40px 0 12px;
}
.main h3 {
  font-size: 19px;
  margin: 24px 0 8px;
}
.main p {
  margin: 0 0 12px;
}
.main ul,
.main ol {
  margin: 0 0 14px;
  padding-left: 26px;
}
.main li {
  margin: 4px 0;
  padding-left: 4px;
}
.step-body ol > li::marker {
  font-weight: 700;
  color: var(--accent);
}
.term {
  text-decoration: underline dotted var(--muted);
  text-underline-offset: 3px;
  cursor: help;
}
.missing {
  color: var(--danger);
  font-weight: 700;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 6px 0 16px;
  font-size: 15px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
  display: table;
}
th,
td {
  text-align: left;
  padding: 9px 12px;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
th {
  background: var(--surface-2);
  font-weight: 600;
  color: var(--text-2);
  font-size: 14px;
}
tr:last-child td {
  border-bottom: 0;
}
td:empty::after {
  content: "";
  display: inline-block;
  min-width: 3em;
  min-height: 1.4em;
}
.table-wrap {
  overflow-x: auto;
}

/* Session band */
.session {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 44px 0 18px;
}
.session-badge {
  flex: none;
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: var(--text);
  color: var(--surface);
  font-weight: 700;
  font-size: 20px;
}
.session-text {
  min-width: 0;
}
.session-kicker {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.session-title {
  font-size: 22px;
  font-weight: 700;
  line-height: 1.2;
}
.session::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--line);
}

/* Step card */
.step {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin: 0 0 18px;
  overflow: hidden;
}
.step-head {
  display: flex;
  gap: 14px;
  align-items: center;
  padding: 16px 20px 12px;
}
.step-num {
  flex: none;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: var(--accent-bg);
  color: var(--accent);
  display: grid;
  place-items: center;
  font-weight: 700;
}
.step.is-done .step-num {
  background: var(--ok);
  color: #fff;
}
.step-head h3 {
  margin: 0;
  font-size: 19px;
  line-height: 1.3;
  flex: 1;
}
.step-time {
  flex: none;
  display: inline-flex;
  gap: 5px;
  align-items: center;
  font-size: 13px;
  color: var(--muted);
}
.step-body {
  padding: 0 20px 6px 68px;
}
.step-foot {
  display: flex;
  justify-content: flex-end;
  padding: 10px 20px 14px;
  border-top: 1px solid var(--line);
  background: var(--surface-2);
}
.done-toggle {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-2);
  cursor: pointer;
  user-select: none;
}
.done-toggle input {
  width: 18px;
  height: 18px;
  accent-color: var(--ok);
}

/* Callouts */
.callout {
  display: flex;
  gap: 12px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  margin: 14px 0;
  border: 1px solid transparent;
}
.callout > .icon {
  margin-top: 0.25em;
}
.callout-body {
  min-width: 0;
  flex: 1;
}
.callout-title {
  font-weight: 700;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 2px;
}
.callout-body > :last-child {
  margin-bottom: 0;
}
.callout.result {
  background: var(--ok-bg);
  color: var(--text);
  border-color: color-mix(in srgb, var(--ok) 25%, transparent);
}
.callout.result .callout-title,
.callout.result > .icon {
  color: var(--ok);
}
.callout.safety {
  background: var(--danger-bg);
  border-color: color-mix(in srgb, var(--danger) 30%, transparent);
}
.callout.safety .callout-title,
.callout.safety > .icon {
  color: var(--danger);
}
.callout.predict {
  background: var(--violet-bg);
  border-color: color-mix(in srgb, var(--violet) 25%, transparent);
}
.callout.predict .callout-title,
.callout.predict > .icon {
  color: var(--violet);
}
.callout.challenge {
  background: var(--surface);
  border: 1.5px dashed var(--warn);
}
.callout.challenge .callout-title,
.callout.challenge > .icon {
  color: var(--warn);
}
.callout.say {
  background: var(--accent-bg);
}
.callout.say .callout-title,
.callout.say > .icon {
  color: var(--accent);
}
.callout.ask {
  background: var(--violet-bg);
}
.callout.ask .callout-title,
.callout.ask > .icon {
  color: var(--violet);
}
.callout.watch {
  background: var(--warn-bg);
}
.callout.watch .callout-title,
.callout.watch > .icon {
  color: var(--warn);
}
.callout.note {
  background: var(--info-bg);
}
.callout.note .callout-title,
.callout.note > .icon {
  color: var(--info);
}
.callout.kit {
  background: var(--surface-2);
  border-color: var(--line);
}

details.reveal {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  margin: 12px 0;
  background: var(--surface);
}
details.reveal > summary {
  display: flex;
  gap: 10px;
  align-items: center;
  padding: 10px 14px;
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  list-style: none;
}
details.reveal > summary::-webkit-details-marker {
  display: none;
}
details.reveal > summary::after {
  content: "";
  margin-left: auto;
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--muted);
  border-bottom: 2px solid var(--muted);
  transform: rotate(45deg);
  transition: transform 0.2s;
}
details.reveal[open] > summary::after {
  transform: rotate(-135deg);
}
details.reveal > .reveal-body {
  padding: 0 16px 6px 42px;
}
details.hint > summary {
  color: var(--warn);
}
details.explain > summary {
  color: var(--info);
}

.selfcheck {
  margin: 14px 0;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  border: 1px solid var(--line);
}
.selfcheck .callout-title {
  color: var(--text-2);
  display: flex;
  gap: 8px;
  align-items: center;
}
.selfcheck label {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 4px 0;
  cursor: pointer;
}
.selfcheck input {
  margin-top: 0.3em;
  width: 17px;
  height: 17px;
  accent-color: var(--ok);
  flex: none;
}

.trouble {
  margin: 14px 0;
}
.trouble .callout-title {
  display: flex;
  gap: 8px;
  align-items: center;
  color: var(--text-2);
  margin-bottom: 6px;
}
.trouble table td:first-child {
  width: 42%;
  font-weight: 500;
}

/* Figures */
figure {
  margin: 16px 0;
}
figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: #f8fafc;
  cursor: zoom-in;
}
figcaption {
  font-size: 14px;
  color: var(--muted);
  margin-top: 6px;
}
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: none;
  place-items: center;
  background: rgba(8, 12, 18, 0.82);
  padding: 24px;
  cursor: zoom-out;
}
.lightbox.open {
  display: grid;
}
.lightbox img {
  max-width: 100%;
  max-height: 100%;
  border-radius: 10px;
  background: #fff;
}

/* Code */
.code {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
  margin: 14px 0;
  background: var(--code-bg);
}
.code-head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px 8px 14px;
  border-bottom: 1px solid var(--line);
  background: var(--surface-2);
  font-size: 14px;
}
.code-title {
  font-weight: 600;
  flex: 1;
  min-width: 0;
}
.code-file {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 12px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.code-btn {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--text-2);
  border-radius: 8px;
  padding: 4px 10px;
  font: 600 13px var(--font);
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  gap: 6px;
  align-items: center;
  white-space: nowrap;
}
.code-btn:hover {
  background: var(--surface-3);
}
.code pre {
  margin: 0;
  padding: 10px 0;
  overflow-x: auto;
  font: 14px / 1.6 var(--mono);
}
.code .ln {
  display: block;
  padding: 0 16px 0 0;
  white-space: pre;
}
.code .ln::before {
  content: attr(data-n);
  display: inline-block;
  width: 3.2em;
  padding-right: 1em;
  text-align: right;
  color: var(--muted);
  opacity: 0.6;
  user-select: none;
}
.code .ln.hl {
  background: var(--code-hl);
  box-shadow: inset 3px 0 0 var(--warn);
}
.tok-kw {
  color: #8a3ffc;
  font-weight: 600;
}
.tok-ty {
  color: #0f62fe;
}
.tok-fn {
  color: #b5530f;
}
.tok-num {
  color: #198038;
}
.tok-str {
  color: #a2191f;
}
.tok-com {
  color: #6f7f8f;
  font-style: italic;
}
.tok-const {
  color: #005d5d;
  font-weight: 600;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .tok-kw {
    color: #be95ff;
  }
  :root:not([data-theme="light"]) .tok-ty {
    color: #78a9ff;
  }
  :root:not([data-theme="light"]) .tok-fn {
    color: #ffb784;
  }
  :root:not([data-theme="light"]) .tok-num {
    color: #6fdc8c;
  }
  :root:not([data-theme="light"]) .tok-str {
    color: #ff8389;
  }
  :root:not([data-theme="light"]) .tok-com {
    color: #8d9aa8;
  }
  :root:not([data-theme="light"]) .tok-const {
    color: #3ddbd9;
  }
}
:root[data-theme="dark"] .tok-kw {
  color: #be95ff;
}
:root[data-theme="dark"] .tok-ty {
  color: #78a9ff;
}
:root[data-theme="dark"] .tok-fn {
  color: #ffb784;
}
:root[data-theme="dark"] .tok-num {
  color: #6fdc8c;
}
:root[data-theme="dark"] .tok-str {
  color: #ff8389;
}
:root[data-theme="dark"] .tok-com {
  color: #8d9aa8;
}
:root[data-theme="dark"] .tok-const {
  color: #3ddbd9;
}
.pre-plain {
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  font: 14px / 1.6 var(--mono);
  overflow-x: auto;
}

/* Parts */
.parts {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(132px, 1fr));
  gap: 10px;
  margin: 14px 0;
}
.part {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  padding: 8px;
  font-size: 13px;
  line-height: 1.3;
}
.part-img {
  aspect-ratio: 4 / 3;
  border-radius: 6px;
  background: #fff;
  display: grid;
  place-items: center;
  overflow: hidden;
  margin-bottom: 6px;
  color: var(--muted);
}
.part-img img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}
.part-qty {
  color: var(--muted);
}
.part-chip {
  display: inline-flex;
  gap: 6px;
  align-items: center;
  padding: 3px 10px;
  margin: 0 6px 6px 0;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface-2);
  font-size: 13px;
}

/* Wiring */
.wiring td:last-child {
  font-family: var(--mono);
  font-size: 14px;
}
.badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 1px 8px;
  border-radius: 999px;
  background: var(--danger-bg);
  color: var(--danger);
  margin-left: 6px;
  font-family: var(--font);
}
.badge.ok {
  background: var(--ok-bg);
  color: var(--ok);
}
.badge.warn {
  background: var(--warn-bg);
  color: var(--warn);
}

/* Knowledge check */
.quiz,
.quiz [data-tier] {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}
.question {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
}
.question legend {
  font-weight: 600;
  padding: 0;
  margin-bottom: 8px;
}
.question fieldset {
  border: 0;
  margin: 0;
  padding: 0;
  min-width: 0;
}
.q-num {
  color: var(--accent);
  margin-right: 6px;
}
.option {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  padding: 8px 12px;
  margin: 6px 0;
  border-radius: 10px;
  border: 1px solid var(--line);
  cursor: pointer;
}
.option:hover {
  background: var(--surface-2);
}
.option input {
  margin-top: 0.3em;
  accent-color: var(--accent);
  flex: none;
}
.option.correct {
  border-color: var(--ok);
  background: var(--ok-bg);
}
.q-note {
  font-size: 14px;
  color: var(--muted);
  margin: 8px 0 0;
}
.quiz-foot {
  font-size: 14px;
  color: var(--muted);
}

/* Rubric */
.main .rubric h3 {
  margin-top: 28px;
}
.rubric-total {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin: 0 0 12px;
}
.rubric-total .chip strong {
  color: var(--text);
}
.rubric td.pts {
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
  color: var(--accent);
  font-weight: 600;
}

/* Index page */
.course-hero {
  padding: 24px 0 8px;
}
.course-hero.has-photo {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  gap: 28px;
  align-items: center;
}
.hero-photo {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}
.course-hero .links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}
@media (max-width: 900px) {
  .course-hero.has-photo {
    grid-template-columns: minmax(0, 1fr);
  }
  .hero-photo {
    order: -1;
    max-height: 260px;
    object-fit: cover;
  }
}
.home-section {
  scroll-margin-top: 76px;
  padding-top: 8px;
}
.main .card h3 {
  font-size: 15px;
  margin: 0 0 6px;
}
.btn {
  display: inline-flex;
  gap: 6px;
  align-items: center;
  padding: 7px 14px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 14px;
  text-decoration: none;
  border: 1px solid var(--line);
  color: var(--text);
  background: var(--surface);
}
.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn:hover {
  filter: brightness(0.97);
}

/* Responsive */
@media (max-width: 1280px) {
  .layout,
  .layout.no-outline {
    grid-template-columns: 248px minmax(0, 1fr);
  }
  .outline {
    display: none;
  }
}
@media (max-width: 900px) {
  .layout,
  .layout.no-outline {
    grid-template-columns: minmax(0, 1fr);
    padding: 0 16px;
  }
  .sidebar {
    display: none;
    position: fixed;
    inset: 60px 0 0 0;
    z-index: 30;
    max-height: none;
    background: var(--surface);
    padding: 20px 16px;
    border-top: 1px solid var(--line);
  }
  body.nav-open .sidebar {
    display: block;
  }
  .menu-btn {
    display: grid;
  }
  .kit-chip,
  .crumb {
    display: none;
  }
  .step-body {
    padding: 0 16px 6px;
  }
  .step-head {
    padding: 14px 16px 10px;
  }
  .main {
    padding-top: 20px;
  }
}
@media (max-width: 520px) {
  body {
    font-size: 16px;
  }
  .topbar {
    gap: 10px;
    padding: 0 12px;
  }
  .brand span:last-child,
  .level-select > span,
  .role-chip {
    display: none;
  }
  .level-select select {
    max-width: 9.5em;
  }
  .audience a {
    padding: 5px 10px;
  }
  /* Teacher pages carry the view switch too: the level choice moves to a second row. */
  .topbar:has(.audience) {
    flex-wrap: wrap;
    align-content: center;
    column-gap: 6px;
    row-gap: 8px;
    padding: 0 8px;
  }
  .topbar:has(.audience):has(.level-select) {
    height: 100px;
  }
  .topbar:has(.audience) .audience a {
    padding: 4px 8px;
    font-size: 14px;
  }
  .topbar:has(.audience) .level-select {
    order: 1;
    flex: 1 0 100%;
  }
  .topbar:has(.audience) .level-select > span {
    display: inline;
  }
  .topbar:has(.audience) .level-select select {
    flex: 1;
    max-width: none;
  }
  body:has(.topbar .audience):has(.topbar .level-select) .sidebar {
    inset: 100px 0 0 0;
  }
  details.reveal > .reveal-body {
    padding-left: 16px;
  }
  .callout {
    padding: 10px 12px;
  }
}

/* Print */
@media print {
  :root {
    --bg: #fff;
    --surface: #fff;
    --surface-2: #fff;
    --shadow: none;
  }
  body {
    font-size: 11.5pt;
    background: #fff;
    color: #000;
  }
  .topbar,
  .sidebar,
  .outline,
  .step-foot,
  .code-btn,
  .icon-btn,
  .lightbox {
    display: none !important;
  }
  .layout {
    display: block;
    padding: 0;
    max-width: none;
  }
  .main {
    padding: 0;
  }
  .main-inner {
    max-width: none;
  }
  .step,
  .question,
  .card,
  .callout,
  table,
  figure,
  .code {
    break-inside: avoid;
    box-shadow: none;
  }
  .session {
    break-before: page;
  }
  details.reveal > summary::after {
    display: none;
  }
  a {
    color: inherit;
    text-decoration: none;
  }
  figure img {
    max-height: 9cm;
    width: auto;
    max-width: 100%;
  }
}

/* Tiers: core / ★ / ★★ */
:root {
  --tier-core: var(--ok);
  --tier-core-bg: var(--ok-bg);
  --tier-star: var(--warn);
  --tier-star-bg: var(--warn-bg);
  --tier-star2: var(--violet);
  --tier-star2-bg: var(--violet-bg);
}
.callout.tier {
  background: var(--surface);
  border: 1.5px solid var(--line);
  border-left-width: 5px;
  align-items: flex-start;
}
.callout.tier-core {
  border-left-color: var(--tier-core);
}
.callout.tier-star {
  border-left-color: var(--tier-star);
}
.callout.tier-star2 {
  border-left-color: var(--tier-star2);
}
.tier-mark {
  flex: none;
  min-width: 34px;
  height: 26px;
  padding: 0 6px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  font-weight: 700;
  font-size: 14px;
}
.tier-core .tier-mark {
  background: var(--tier-core-bg);
  color: var(--tier-core);
}
.tier-star .tier-mark {
  background: var(--tier-star-bg);
  color: var(--tier-star);
}
.tier-star2 .tier-mark {
  background: var(--tier-star2-bg);
  color: var(--tier-star2);
}
.tier-core .callout-title {
  color: var(--tier-core);
}
.tier-star .callout-title {
  color: var(--tier-star);
}
.tier-star2 .callout-title {
  color: var(--tier-star2);
}
.tier-pill {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 1px 9px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 700;
  white-space: nowrap;
  margin-right: 6px;
}
.tier-pill.tier-core {
  background: var(--tier-core-bg);
  color: var(--tier-core);
}
.tier-pill.tier-star {
  background: var(--tier-star-bg);
  color: var(--tier-star);
}
.tier-pill.tier-star2 {
  background: var(--tier-star2-bg);
  color: var(--tier-star2);
}
.levels .req {
  margin: 2px 0 6px;
  line-height: 2;
}
.levels .part-chip {
  margin: 0 4px 0 0;
}
.tier-list {
  list-style: none;
  padding: 0 !important;
  margin: 4px 0 0 !important;
  font-size: 14px;
  color: var(--text-2);
}
.tier-list li {
  display: flex;
  gap: 6px;
  align-items: baseline;
  margin: 4px 0 !important;
  padding: 0 !important;
}
.role-chip {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-2);
  background: var(--surface-3);
  border-radius: 999px;
  padding: 4px 12px;
  white-space: nowrap;
}
.map-topic.is-optional .map-topic-name {
  color: var(--muted);
}

/* Level variants */
.variants {
  margin: 14px 0;
}
.level-select {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font: 600 13px var(--font);
  color: var(--muted);
}
.level-select select {
  font: 600 14px var(--font);
  color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 5px 12px;
  cursor: pointer;
}
.level-select select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.js .variant:not(.is-active) {
  display: none;
}
.callout.recall {
  background: var(--surface);
  border: 1.5px solid var(--accent);
}
.callout.recall .callout-title,
.callout.recall > .icon {
  color: var(--accent);
}
.callout.debug {
  background: var(--danger-bg);
  border-color: color-mix(in srgb, var(--danger) 25%, transparent);
}
.callout.debug .callout-title,
.callout.debug > .icon {
  color: var(--danger);
}
.pdf-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin: 0 0 24px;
  font-size: 14px;
  color: var(--text-2);
}
@media print {
  .pdf-bar,
  .tier-more {
    display: none !important;
  }
}

/* Course book: cover, contents and one lesson per printed section */
.book-cover {
  padding: 48px 0 32px;
}
.book-cover .variant {
  margin: 16px 0 0;
  font-size: 18px;
}
.book-meta {
  color: var(--muted);
}
.book-toc {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 0 0 32px;
}
.book-toc a {
  display: flex;
  gap: 12px;
  padding: 6px 0;
  border-bottom: 1px solid var(--line);
  color: var(--text);
  text-decoration: none;
}
.toc-num {
  min-width: 3em;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.book-part {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 2px solid var(--line-strong);
}
@page book {
  margin: 16mm 14mm 18mm;
  @bottom-center {
    content: counter(page) " / " counter(pages);
    font-size: 9pt;
    color: #5f6b7a;
  }
}
@media print {
  .book {
    page: book;
  }
  .book-cover {
    padding-top: 30vh;
  }
  .book-toc,
  .book-part {
    break-before: page;
  }
  .book-part {
    margin-top: 0;
    padding-top: 0;
    border-top: 0;
  }
}

/* Course home blocks. Same structure as the program's course page
   (design/pages/03-learn.html?course=library&id=…, design/assets/ui.css «Course page body»). */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}
.block-label {
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}
.home-section + .home-section {
  margin-top: 28px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}
.outline-sub {
  display: flex;
  flex-direction: column;
  margin: 1px 0 4px 10px;
  padding-left: 8px;
  border-left: 1px solid var(--line);
}
.outline-sub a {
  font-size: 13px;
  padding: 3px 8px;
}
.outline-sub .o-num {
  width: 14px;
  flex: none;
  color: var(--muted);
  font-weight: 650;
}
.mine-badge {
  display: none;
  padding: 1px 8px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 650;
  color: var(--accent);
  background: var(--accent-bg);
  border: 1px solid color-mix(in srgb, var(--accent) 45%, transparent);
  white-space: nowrap;
}
.is-mine .mine-badge {
  display: inline-flex;
}
.final-card .tier-pill,
.final-needs .tier-pill,
.level-matrix .tier-pill,
.tier-list .tier-pill {
  min-width: 28px;
  justify-content: center;
  padding: 0 6px;
  font-size: 11px;
  line-height: 20px;
  margin-right: 0;
}

/* «Чему ты научишься» */
.main .outcomes {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 28px;
}
.main .outcomes li {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  margin: 0;
  padding: 0;
}
.outcomes .icon {
  width: 20px;
  height: 20px;
  flex: none;
  margin-top: 2px;
  padding: 3px;
  border-radius: 50%;
  box-sizing: border-box;
  background: var(--ok-bg);
  color: var(--ok);
}

/* Program: topics and lesson rows */
.topic-block {
  margin: 0 0 22px;
}
.topic-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 10px;
}
.topic-head::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--line);
}
details.topic-block > summary {
  cursor: pointer;
  list-style: none;
  padding: 10px 12px;
  border: 1px dashed var(--line-strong);
  border-radius: 12px;
}
details.topic-block > summary::-webkit-details-marker {
  display: none;
}
details.topic-block > summary::after {
  display: none;
}
details.topic-block[open] > summary {
  margin-bottom: 10px;
}
.topic-badge {
  width: 40px;
  height: 40px;
  flex: none;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: var(--text);
  color: var(--bg);
  font-weight: 750;
  font-size: 18px;
}
details.topic-block .topic-badge {
  background: var(--surface-3);
  color: var(--text-2);
}
.topic-text {
  display: flex;
  flex-direction: column;
  flex: 1;
}
.topic-num {
  font-size: 11.5px;
  font-weight: 650;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.topic-name {
  font-size: 18px;
  font-weight: 750;
  line-height: 1.2;
}
.topic-count {
  font-size: 13px;
  color: var(--muted);
  white-space: nowrap;
}
.main .lesson-rows {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.main .lesson-row {
  position: relative;
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr) 20px;
  gap: 14px;
  align-items: start;
  margin: 0;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  transition:
    border-color 0.15s,
    background 0.15s;
}
.lesson-row.is-plan {
  background: transparent;
  border-style: dashed;
}
.lesson-row:has(.lesson-link):hover {
  border-color: var(--accent);
  background: var(--surface-2);
}
.lesson-row:has(.lesson-link:focus-visible) {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.lesson-n {
  min-width: 44px;
  height: 32px;
  padding: 0 6px;
  border-radius: 9px;
  display: grid;
  place-items: center;
  font-weight: 750;
  font-size: 13px;
  background: var(--surface-3);
  white-space: nowrap;
}
.lesson-row-main {
  display: flex;
  flex-direction: column;
  gap: 5px;
  min-width: 0;
}
.lesson-row-title {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
  align-items: baseline;
}
.lesson-row-title :is(a, b) {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}
/* The whole row opens the lesson; the teacher's guide button stays clickable above it. */
.lesson-link::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 12px;
}
.lesson-link:focus-visible {
  outline: none;
}
.lesson-row:hover .lesson-link {
  color: var(--accent);
}
.lesson-row .links {
  position: relative;
  z-index: 1;
  display: flex;
  gap: 8px;
}
.lesson-row-meta {
  font-size: 13px;
  color: var(--muted);
}
.main .lesson-row p {
  margin: 0;
  font-size: 14px;
  color: var(--text-2);
}
.lesson-go {
  align-self: center;
  font-size: 22px;
  line-height: 1;
  color: var(--muted);
}
.lesson-row:hover .lesson-go {
  color: var(--accent);
}
.tier-list li {
  align-items: flex-start;
  gap: 8px;
}

/* Final task: one card per level, cumulative requirements */
.main .final-levels {
  list-style: none;
  padding: 0;
  margin: 14px 0;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0 14px;
}
.main .final-card {
  display: grid;
  grid-row: span 4;
  grid-template-rows: subgrid;
  gap: 12px;
  margin: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}
.final-card.is-mine {
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
  background: color-mix(in srgb, var(--accent-bg) 45%, var(--surface));
}
.final-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}
.main .final-head h3 {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-size: 16px;
}
.final-art {
  border-radius: 10px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: #fff;
  padding: 6px;
}
.final-art img {
  display: block;
  width: 100%;
  height: 132px;
  object-fit: contain;
}
.main .final-task {
  margin: 0;
  font-size: 14px;
}
.final-need {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}
.main .final-needs {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.main .final-needs li {
  display: flex;
  gap: 8px;
  align-items: flex-start;
  margin: 0;
  padding: 0;
  font-size: 13.5px;
  line-height: 1.45;
}
.lesson-ids {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 4px;
  vertical-align: 1px;
}
.lesson-ids > span {
  padding: 0 6px;
  border-radius: 6px;
  background: var(--surface-3);
  border: 1px solid var(--line);
  font-size: 12.5px;
  font-weight: 650;
  line-height: 20px;
}

/* Levels: comparison matrix, the chosen level's column outlined */
.level-matrix {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  margin: 0 0 14px;
}
.level-matrix table {
  width: 100%;
  border: 0;
  border-collapse: separate;
  border-spacing: 0;
  table-layout: fixed;
  font-size: 14px;
  margin: 0;
}
.level-matrix :is(th, td) {
  padding: 11px 14px;
  text-align: left;
  vertical-align: top;
  border: 0;
  border-top: 1px solid var(--line);
  background: none;
}
.level-matrix thead :is(th, td) {
  border-top: 0;
}
.level-matrix thead td {
  width: 150px;
}
.level-matrix thead th {
  font-weight: 700;
}
.level-matrix thead .mine-badge {
  margin-top: 6px;
}
.matrix-level,
.matrix-tier {
  display: flex;
  align-items: center;
  gap: 8px;
}
.matrix-level {
  font-size: 15px;
}
.level-matrix tbody th {
  font-size: 13px;
  font-weight: 650;
  color: var(--muted);
}
.level-matrix td {
  color: var(--text-2);
}
.level-matrix .is-mine {
  background: color-mix(in srgb, var(--accent-bg) 55%, transparent);
  color: var(--text);
  box-shadow:
    inset 1px 0 0 var(--accent),
    inset -1px 0 0 var(--accent);
}
.level-matrix thead th.is-mine {
  box-shadow:
    inset 1px 0 0 var(--accent),
    inset -1px 0 0 var(--accent),
    inset 0 2px 0 var(--accent);
}
.level-matrix tbody tr:last-child td.is-mine {
  box-shadow:
    inset 1px 0 0 var(--accent),
    inset -1px 0 0 var(--accent),
    inset 0 -1px 0 var(--accent);
}

/* «Как проходит урок»: a real lesson's plan, then the rules */
.lesson-plan {
  margin: 0 0 14px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}
.lesson-plan figcaption {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 12px;
  font-size: 14px;
}
.lesson-plan figcaption a {
  font-weight: 650;
}
.plan-session {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr);
  gap: 14px;
}
.plan-head {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2px;
  font-size: 13px;
  line-height: 1.35;
  color: var(--text-2);
}
.plan-head b {
  font-size: 14.5px;
  color: var(--text);
}
.main .plan-steps {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 4px;
}
.main .plan-steps li {
  flex-basis: 0;
  min-width: 88px;
  margin: 0;
  padding: 8px 10px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  border-radius: 9px;
  background: var(--surface-3);
  border: 1px solid var(--line);
  font-size: 12.5px;
  line-height: 1.3;
}
.plan-n {
  font-weight: 750;
  color: var(--accent);
}
.plan-t {
  overflow-wrap: break-word;
  hyphens: auto;
}
.plan-m {
  color: var(--muted);
  margin-top: auto;
  padding-top: 2px;
  white-space: nowrap;
}
.main .principles {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(230px, 100%), 1fr));
  gap: 10px;
}
.main .principles li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  margin: 0;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--text-2);
}
.principles b {
  display: block;
  color: var(--text);
  font-size: 14px;
  margin-bottom: 2px;
}
.principle-one {
  color: var(--text);
}
.principles .icon {
  width: 32px;
  height: 32px;
  flex: none;
  padding: 7px;
  border-radius: 9px;
  box-sizing: border-box;
  background: var(--accent-bg);
  color: var(--accent);
}
@media (max-width: 900px) {
  .main .final-levels {
    grid-template-columns: minmax(0, 1fr);
    gap: 14px;
  }
  .main .final-card {
    grid-row: auto;
    grid-template-rows: none;
  }
  .plan-session {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }
  .plan-head {
    flex-direction: row;
    gap: 8px;
  }
}
@media (max-width: 640px) {
  .main .outcomes {
    grid-template-columns: minmax(0, 1fr);
  }
  .main .plan-steps {
    flex-direction: column;
  }
  .level-matrix table,
  .level-matrix :is(thead, tbody, tr, th, td) {
    display: block;
  }
  .level-matrix thead {
    display: none;
  }
  .level-matrix td::before {
    content: attr(data-level-title);
    display: block;
    font-size: 12px;
    font-weight: 700;
    color: var(--muted);
  }
}
@media print {
  .lesson-go,
  .mine-badge {
    display: none !important;
  }
  .main .lesson-row,
  .main .final-card,
  .lesson-plan,
  .main .principles li {
    break-inside: avoid;
  }
}
.tier-list li[hidden] {
  display: none;
}