:root {
  --bg: #f4f7fb;
  --paper: #ffffff;
  --ink: #16212d;
  --muted: #64748b;
  --line: #d9e2ec;
  --soft: #edf6f6;
  --soft-blue: #eef4ff;
  --brand: #0f766e;
  --brand-strong: #0d4f56;
  --navy: #18223a;
  --green: #18794e;
  --amber: #b86b12;
  --violet: #5657b8;
  --rose: #b42318;
  --shadow: 0 18px 45px rgba(22, 33, 45, 0.08);
  --shadow-soft: 0 10px 28px rgba(22, 33, 45, 0.06);
  --radius: 8px;
  font-family:
    "Aptos", "Segoe UI Variable", "Segoe UI", ui-sans-serif, system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    linear-gradient(180deg, #f8fbff 0%, var(--bg) 38%, #ffffff 100%);
  color: var(--ink);
  line-height: 1.62;
}

h1,
h2,
h3,
strong {
  font-family:
    "Bahnschrift", "Aptos Display", "Aptos", "Segoe UI Variable", "Segoe UI", sans-serif;
}

a {
  color: var(--brand-strong);
}

button,
input {
  font: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) minmax(260px, 440px);
  gap: 18px;
  align-items: center;
  padding: 14px 24px;
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.topbar h1 {
  margin: 0;
  font-size: 1.15rem;
  line-height: 1.2;
}

.eyebrow {
  margin: 0 0 4px;
  color: var(--brand-strong);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

.search {
  display: grid;
  gap: 4px;
}

.search span {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
}

.search input {
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfdff;
  color: var(--ink);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

.search input:focus {
  outline: 3px solid rgba(15, 118, 110, 0.18);
  border-color: var(--brand);
}

.layout {
  display: grid;
  grid-template-columns: 310px minmax(0, 1fr);
  align-items: start;
  min-width: 0;
  transition: grid-template-columns 180ms ease;
}

.sidebar {
  position: sticky;
  top: 77px;
  height: calc(100vh - 77px);
  padding: 18px 14px;
  overflow: auto;
  background: #ffffff;
  border-right: 1px solid var(--line);
  transition:
    padding 180ms ease,
    width 180ms ease;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 8px 12px;
}

.sidebar nav {
  display: grid;
  gap: 5px;
}

.nav-section {
  display: grid;
  gap: 6px;
}

.nav-section + .nav-section {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.nav-section strong {
  padding: 0 10px 6px;
  color: var(--muted);
  font-size: 0.74rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.nav-link {
  display: grid;
  grid-template-columns: 24px 1fr;
  gap: 8px;
  align-items: start;
  padding: 10px;
  color: #334155;
  text-decoration: none;
  border-radius: var(--radius);
  font-size: 0.91rem;
  line-height: 1.25;
}

.nav-link:hover,
.nav-link.active {
  background: var(--soft);
  color: var(--brand-strong);
}

.nav-link small {
  color: var(--muted);
  font-weight: 800;
}

main {
  width: min(100%, 1520px);
  max-width: 100%;
  min-width: 0;
  margin: 0 auto;
  padding: 26px clamp(16px, 3vw, 42px) 72px;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(220px, 0.48fr);
  gap: 24px;
  align-items: end;
  min-height: 430px;
  overflow: hidden;
  padding: clamp(28px, 3.2vw, 42px);
  border-radius: var(--radius);
  min-width: 0;
  background:
    linear-gradient(90deg, rgba(8, 22, 34, 0.86) 0%, rgba(8, 22, 34, 0.66) 44%, rgba(8, 22, 34, 0.18) 100%),
    url("assets/genai-architect-workspace.png") center / cover no-repeat;
  color: #ffffff;
  box-shadow: var(--shadow);
}

.hero-copy,
.identity-card {
  position: relative;
  z-index: 1;
  min-width: 0;
}

.hero .eyebrow {
  color: #9ee6df;
}

.hero h2 {
  max-width: 820px;
  margin: 0 0 14px;
  font-size: 2.58rem;
  line-height: 1.03;
}

.hero p {
  max-width: 760px;
  color: #e4edf5;
  font-size: 1.04rem;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(120px, 1fr));
  gap: 8px;
  max-width: 840px;
  margin-top: 22px;
}

.hero-stats span {
  display: grid;
  min-height: 62px;
  align-content: center;
  padding: 10px 12px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.1);
  color: #d9e7ef;
  font-size: 0.92rem;
  backdrop-filter: blur(8px);
}

.hero-stats b {
  color: #ffffff;
  font-size: 1.25rem;
  line-height: 1;
}

.hero-actions,
.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 148px;
  min-height: 44px;
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  color: var(--brand-strong);
  font-weight: 800;
  text-align: center;
  text-decoration: none;
}

.button.primary {
  background: var(--brand);
  border-color: var(--brand);
  color: #ffffff;
}

.button:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-soft);
}

.identity-card {
  padding: 16px;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  backdrop-filter: blur(16px);
}

.identity-card p {
  margin: 8px 0 0;
  color: #e4edf5;
  font-size: 0.98rem;
}

.pill-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.pill-grid span,
.tag {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 5px 9px;
  border: 1px solid #c7d8e5;
  border-radius: 999px;
  background: #ffffff;
  color: #315466;
  font-size: 0.86rem;
  font-weight: 750;
}

.identity-card .pill-grid span {
  border-color: rgba(255, 255, 255, 0.22);
  background: rgba(255, 255, 255, 0.18);
  color: #ffffff;
}

.strategy-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-top: 18px;
}

.strategy-strip div {
  min-height: 128px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow-soft);
}

.strategy-strip strong {
  display: block;
  margin-bottom: 8px;
  color: var(--brand-strong);
  font-size: 1.05rem;
}

.strategy-strip span {
  color: #475569;
}

.diagram-band,
.progress-panel {
  margin-top: 22px;
  padding: clamp(18px, 3vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow-soft);
}

.section-heading {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: end;
  justify-content: space-between;
  margin-bottom: 18px;
}

.section-heading h2,
.progress-panel h2,
.module-title h2 {
  margin: 0;
  font-size: 2.05rem;
  line-height: 1.15;
}

.flow-diagram {
  display: grid;
  grid-template-columns: repeat(4, minmax(160px, 1fr));
  gap: 12px;
}

.flow-diagram div {
  position: relative;
  min-height: 118px;
  padding: 16px;
  border: 1px solid #c8d6e4;
  border-radius: var(--radius);
  background: linear-gradient(180deg, #ffffff 0%, #f8fbfd 100%);
  font-weight: 850;
}

.flow-diagram div:nth-child(3n) {
  border-color: rgba(86, 87, 184, 0.28);
}

.flow-diagram div:nth-child(4n) {
  border-color: rgba(184, 107, 18, 0.3);
}

.flow-diagram small {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  font-weight: 600;
}

.progress-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 340px);
  gap: 20px;
  align-items: center;
}

.progress-meter span {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-weight: 800;
}

.progress-meter div {
  height: 12px;
  overflow: hidden;
  border-radius: 999px;
  background: #e6edf4;
}

.progress-meter i {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--brand), var(--green), var(--amber));
}

.module {
  margin-top: 34px;
  padding: 34px 0 42px;
  border-top: 1px solid var(--line);
  scroll-margin-top: 96px;
}

.module-title {
  display: grid;
  gap: 8px;
  max-width: 1080px;
  margin-bottom: 20px;
}

.module-title p {
  max-width: 920px;
  margin: 0;
  color: #475569;
}

.module-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.complete-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  width: max-content;
  max-width: 100%;
  min-height: 38px;
  padding: 7px 11px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfdff;
  cursor: pointer;
  font-weight: 750;
}

.complete-toggle input {
  accent-color: var(--brand);
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.topic-card,
.wide-card,
.mini-card,
.resource-card {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  box-shadow: var(--shadow-soft);
}

.topic-card {
  display: grid;
  align-content: start;
  padding: 18px;
}

.topic-card h3,
.wide-card h3,
.mini-card h3,
.resource-card h3 {
  margin: 0 0 8px;
  color: #1f2a37;
  line-height: 1.25;
}

.topic-card p,
.wide-card p,
.mini-card p,
.resource-card p {
  margin: 0 0 10px;
  color: #475569;
}

.topic-card ul,
.wide-card ul,
.mini-card ul {
  margin: 8px 0 0;
  padding-left: 20px;
}

.topic-card li,
.wide-card li,
.mini-card li {
  margin: 4px 0;
}

.example {
  margin-top: 14px;
  padding: 12px;
  border-left: 4px solid var(--brand);
  background: #f4f9fc;
  color: #334155;
}

.warning {
  border-left-color: var(--amber);
  background: #fff8ed;
}

.success {
  border-left-color: var(--green);
  background: #f0faf4;
}

.wide-card {
  padding: 18px;
  margin-top: 14px;
}

.mini-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.mini-card {
  padding: 15px;
}

.roadmap {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.month {
  display: grid;
  gap: 12px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  box-shadow: var(--shadow-soft);
}

.month strong {
  color: var(--brand-strong);
  font-size: 1.05rem;
}

.month p {
  margin: 0;
  color: #475569;
}

.checklist-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.az-item {
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfdff;
}

.az-item strong {
  color: var(--brand-strong);
}

.az-item p {
  margin: 6px 0 0;
  color: #475569;
}

.schedule {
  display: grid;
  grid-template-columns: repeat(7, minmax(120px, 1fr));
  gap: 10px;
  overflow-x: auto;
  padding-bottom: 4px;
}

.day {
  min-width: 145px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  box-shadow: var(--shadow-soft);
}

.day strong {
  display: block;
  margin-bottom: 8px;
  color: var(--brand-strong);
}

.day ul {
  margin: 0;
  padding-left: 18px;
}

.resource-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 10px;
}

.resource-card {
  display: grid;
  gap: 8px;
  min-height: 190px;
  padding: 18px;
  color: inherit;
  text-decoration: none;
}

.resource-card:hover {
  transform: translateY(-2px);
  border-color: rgba(15, 118, 110, 0.38);
}

.resource-card small {
  color: var(--muted);
  font-weight: 800;
}

.resource-card span {
  align-self: end;
  color: var(--brand-strong);
  font-weight: 850;
}

.page-intro,
.lesson-hero,
.diagram-card,
.detail-section {
  margin-top: 26px;
  padding: clamp(20px, 2.8vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow-soft);
}

.page-intro,
.lesson-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(250px, 340px);
  gap: 18px;
  align-items: start;
}

.page-intro h2,
.lesson-hero h2,
.detail-section h2,
.diagram-card h2 {
  margin: 0;
  font-size: 2rem;
  line-height: 1.08;
}

.page-intro p,
.lesson-hero p,
.diagram-caption {
  margin: 0;
  color: #475569;
}

.page-intro-copy,
.page-intro-note,
.lesson-hero-copy {
  display: grid;
  gap: 12px;
}

.page-intro-note {
  align-content: start;
  padding: 16px;
  border: 1px solid #d7e4f0;
  border-radius: var(--radius);
  background:
    radial-gradient(circle at top right, rgba(15, 118, 110, 0.12), transparent 45%),
    linear-gradient(180deg, #ffffff 0%, #f8fbfd 100%);
}

.page-intro-note strong {
  color: var(--brand-strong);
  font-size: 0.98rem;
}

.lesson-directory {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.lesson-card {
  display: grid;
  gap: 14px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(circle at top right, rgba(15, 118, 110, 0.08), transparent 42%),
    linear-gradient(180deg, #ffffff 0%, #f8fbfd 100%);
  box-shadow: var(--shadow-soft);
}

.lesson-card h3 {
  margin: 0;
  font-size: 1.28rem;
  line-height: 1.2;
}

.lesson-card p {
  margin: 0;
  color: #475569;
}

.lesson-card-top,
.lesson-card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  justify-content: space-between;
}

.lesson-pill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.lesson-pill-list span {
  display: inline-flex;
  min-height: 30px;
  padding: 6px 10px;
  border: 1px solid #d7e4f0;
  border-radius: 999px;
  background: #f8fbff;
  color: #315466;
  font-size: 0.84rem;
  font-weight: 700;
}

.lesson-shell {
  display: grid;
  gap: 0;
}

.accordion-shell {
  display: grid;
  gap: 18px;
}

.accordion-group {
  display: grid;
  gap: 12px;
}

.accordion-item {
  border: 1px solid #d7e4f0;
  border-radius: var(--radius);
  background:
    radial-gradient(circle at top right, rgba(15, 118, 110, 0.08), transparent 42%),
    linear-gradient(180deg, #ffffff 0%, #f8fbfd 100%);
  overflow: hidden;
}

.accordion-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 20px;
  cursor: pointer;
  list-style: none;
}

.accordion-item summary::-webkit-details-marker {
  display: none;
}

.accordion-copy {
  display: grid;
  gap: 6px;
}

.accordion-copy .eyebrow {
  margin-bottom: 0;
}

.accordion-copy strong {
  color: #173043;
  font-size: 1.05rem;
  line-height: 1.2;
}

.accordion-summary-right {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}

.accordion-meta {
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 800;
}

.accordion-icon {
  width: 12px;
  height: 12px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  color: var(--brand-strong);
  transform: rotate(45deg) translateY(-1px);
  transition: transform 180ms ease;
}

.accordion-item[open] > summary {
  border-bottom: 1px solid #d7e4f0;
}

.accordion-item[open] .accordion-icon {
  transform: rotate(225deg) translateY(-1px);
}

.accordion-body {
  display: grid;
  gap: 16px;
  padding: 20px;
}

.accordion-intro p {
  margin: 0;
  color: #475569;
}

.warning-accordion {
  border-color: rgba(184, 107, 18, 0.3);
  background: linear-gradient(180deg, #fffdf8 0%, #fff7ec 100%);
}

.success-accordion {
  border-color: rgba(24, 121, 78, 0.25);
  background: linear-gradient(180deg, #f8fffa 0%, #eff9f2 100%);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.92rem;
}

.breadcrumb a {
  color: var(--brand-strong);
  text-decoration: none;
  font-weight: 700;
}

.lesson-meta-card {
  display: grid;
  gap: 14px;
  min-width: 0;
  border-color: rgba(15, 118, 110, 0.16);
  background:
    linear-gradient(180deg, #183547 0%, #102633 100%);
  color: #ffffff;
}

.lesson-meta-card .complete-toggle {
  background: rgba(255, 255, 255, 0.14);
  border-color: rgba(255, 255, 255, 0.2);
  color: #ffffff;
}

.lesson-meta-card .complete-toggle input {
  accent-color: #ffffff;
}

.lesson-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.lesson-topic {
  background: linear-gradient(180deg, #ffffff 0%, #fbfdff 100%);
}

.bullet-panel {
  padding: 16px 18px;
  border: 1px solid #d7e4f0;
  border-radius: var(--radius);
  background: linear-gradient(180deg, #ffffff 0%, #f8fbfd 100%);
}

.bullet-panel ul {
  margin: 0;
  padding-left: 20px;
}

.bullet-panel li + li {
  margin-top: 10px;
}

.notes-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.note-card {
  display: grid;
  gap: 12px;
  padding: 20px;
  border: 1px solid #d5e2ee;
  border-radius: var(--radius);
  background:
    radial-gradient(circle at top right, rgba(15, 118, 110, 0.08), transparent 40%),
    linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
  box-shadow: var(--shadow-soft);
}

.note-card h3 {
  margin: 0;
  color: #173043;
  font-size: 1.16rem;
  line-height: 1.25;
}

.note-card p {
  margin: 0;
  color: #425466;
}

.note-card ul {
  margin: 0;
  padding-left: 20px;
}

.note-card li + li {
  margin-top: 8px;
}

.warning-panel .bullet-panel {
  border-color: rgba(184, 107, 18, 0.28);
  background: linear-gradient(180deg, #fffdf8 0%, #fff7ec 100%);
}

.success-panel .bullet-panel {
  border-color: rgba(24, 121, 78, 0.24);
  background: linear-gradient(180deg, #f8fffa 0%, #eff9f2 100%);
}

.diagram-card .section-heading {
  margin-bottom: 20px;
}

.diagram-caption {
  max-width: 620px;
}

.pipeline-diagram,
.grid-diagram {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.stack-diagram {
  display: grid;
  gap: 10px;
}

.stack-diagram article,
.pipeline-diagram article,
.loop-diagram article,
.grid-diagram article {
  position: relative;
  padding: 16px;
  border: 1px solid #c8d6e4;
  border-radius: var(--radius);
  background:
    radial-gradient(circle at top right, rgba(15, 118, 110, 0.1), transparent 42%),
    linear-gradient(180deg, #ffffff 0%, #f8fbfd 100%);
}

.stack-diagram article strong,
.pipeline-diagram article strong,
.loop-diagram article strong,
.grid-diagram article strong {
  display: block;
  margin-bottom: 8px;
  color: var(--brand-strong);
  font-size: 1rem;
}

.stack-diagram article p,
.pipeline-diagram article p,
.loop-diagram article p,
.grid-diagram article p {
  margin: 0;
  color: #475569;
}

.stack-diagram article:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -11px;
  width: 2px;
  height: 12px;
  background: linear-gradient(180deg, rgba(15, 118, 110, 0.55), rgba(15, 118, 110, 0.1));
  transform: translateX(-50%);
}

.pipeline-diagram article:not(:last-child)::after {
  content: "→";
  position: absolute;
  right: -13px;
  top: 50%;
  color: var(--brand-strong);
  font-size: 1.15rem;
  font-weight: 900;
  transform: translateY(-50%);
}

.loop-diagram {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.loop-diagram article:nth-child(1) {
  border-color: rgba(15, 118, 110, 0.28);
}

.loop-diagram article:nth-child(2) {
  border-color: rgba(24, 121, 78, 0.28);
}

.loop-diagram article:nth-child(3) {
  border-color: rgba(184, 107, 18, 0.28);
}

.loop-diagram article:nth-child(4) {
  border-color: rgba(86, 87, 184, 0.28);
}

.grid-diagram article:nth-child(odd) {
  border-color: rgba(15, 118, 110, 0.28);
}

.grid-diagram article:nth-child(even) {
  border-color: rgba(24, 121, 78, 0.24);
}

.hidden {
  display: none !important;
}

.icon-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  color: var(--ink);
  cursor: pointer;
}

.menu-button {
  display: none;
  flex-direction: column;
  gap: 4px;
}

.menu-button span {
  width: 18px;
  height: 2px;
  background: var(--ink);
}

.close-button {
  display: none;
}

.collapse-button span {
  display: block;
  width: 10px;
  height: 10px;
  border-left: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg) translate(2px, -2px);
  transition: transform 180ms ease;
}

.to-top {
  position: fixed;
  right: 18px;
  bottom: 18px;
  width: 42px;
  height: 42px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: 50%;
  background: var(--brand);
  color: #ffffff;
  font-size: 1.3rem;
  font-weight: 900;
  cursor: pointer;
  box-shadow: var(--shadow);
}

mark {
  background: #fff1a8;
  color: inherit;
}

@media (min-width: 1181px) {
  .layout.sidebar-collapsed {
    grid-template-columns: 76px minmax(0, 1fr);
  }

  .layout.sidebar-collapsed .sidebar {
    padding-inline: 10px;
    overflow-x: hidden;
  }

  .layout.sidebar-collapsed .sidebar-header {
    justify-content: center;
    padding-inline: 0;
  }

  .layout.sidebar-collapsed .sidebar-header strong,
  .layout.sidebar-collapsed .nav-section strong,
  .layout.sidebar-collapsed .nav-link span {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
  }

  .layout.sidebar-collapsed .collapse-button span {
    transform: rotate(225deg) translate(2px, -2px);
  }

  .layout.sidebar-collapsed .sidebar nav {
    justify-items: center;
  }

  .layout.sidebar-collapsed .nav-link {
    grid-template-columns: 1fr;
    justify-items: center;
    width: 44px;
    min-height: 44px;
    padding: 10px 6px;
  }
}

@media (max-width: 1180px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .menu-button {
    display: inline-flex;
  }

  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 40;
    width: min(88vw, 340px);
    height: 100vh;
    transform: translateX(-105%);
    transition: transform 180ms ease;
    box-shadow: var(--shadow);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .close-button {
    display: inline-flex;
  }

  .collapse-button {
    display: none;
  }
}

@media (max-width: 980px) {
  .topbar {
    grid-template-columns: auto 1fr;
  }

  .top-actions {
    grid-column: 1 / -1;
  }

  .hero,
  .progress-panel,
  .page-intro,
  .lesson-hero {
    grid-template-columns: 1fr;
  }

  .hero {
    align-items: center;
    min-height: auto;
  }

  .hero-copy,
  .identity-card,
  .hero h2,
  .hero p,
  .hero-stats,
  .hero-actions,
  .pill-grid {
    width: 100%;
    max-width: 100%;
  }

  .hero-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .button {
    min-width: 0;
  }

  .hero h2 {
    font-size: 2.72rem;
  }

  .flow-diagram,
  .grid,
  .mini-grid,
  .roadmap,
  .checklist-grid,
  .resource-grid,
  .strategy-strip,
  .lesson-directory,
  .pipeline-diagram,
  .grid-diagram,
  .loop-diagram,
  .lesson-grid,
  .notes-grid {
    grid-template-columns: 1fr;
  }

  .pipeline-diagram article::after {
    display: none;
  }
}

@media (max-width: 640px) {
  .topbar {
    padding: 12px;
  }

  .topbar h1 {
    font-size: 1rem;
  }

  main {
    padding: 14px 12px 64px;
  }

  .hero,
  .diagram-band,
  .progress-panel,
  .page-intro,
  .lesson-hero,
  .diagram-card,
  .detail-section {
    padding: 18px;
  }

  .hero h2 {
    font-size: 1.86rem;
  }

  .hero p {
    font-size: 0.95rem;
  }

  .identity-card {
    display: none;
  }

  .hero-stats {
    gap: 7px;
  }

  .hero-stats span {
    min-height: 56px;
    padding: 8px 9px;
    font-size: 0.82rem;
  }

  .hero-actions .button {
    flex: 1 1 calc(50% - 8px);
    padding: 8px 9px;
    font-size: 0.9rem;
  }

  .accordion-item summary {
    padding: 16px;
  }

  .accordion-summary-right {
    gap: 10px;
  }

  .accordion-body {
    padding: 16px;
  }

  .section-heading h2,
  .progress-panel h2,
  .module-title h2 {
    font-size: 1.58rem;
  }

  .complete-toggle {
    width: 100%;
  }
}

@media print {
  .topbar,
  .sidebar,
  .to-top,
  .complete-toggle {
    display: none;
  }

  .layout {
    display: block;
  }

  main {
    width: 100%;
    padding: 0;
  }

  .hero,
  .diagram-band,
  .progress-panel,
  .topic-card,
  .wide-card,
  .month,
  .day,
  .resource-card {
    box-shadow: none;
    break-inside: avoid;
  }
}