:root {
  --cs-font-sans: Inter, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --cs-font-mono: "Cascadia Code", "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --cs-ink: #18202b;
  --cs-heading: #111927;
  --cs-text: #1f2a37;
  --cs-muted: #5b6676;
  --cs-surface: #ffffff;
  --cs-surface-soft: #f4f8fb;
  --cs-line: #d9e4ec;
  --cs-cyan: #16c7dd;
  --cs-cyan-soft: #d9f8fb;
  --cs-blue: #2467d9;
  --cs-indigo: #3044ba;
  --cs-graphite: #171921;
  --cs-link: #1f63d6;
  --cs-link-hover: #203fa9;
  --cs-table-head-bg: linear-gradient(135deg, #3044ba 0%, #2467d9 58%, #16c7dd 100%);
  --cs-table-row-alt: #f0fbfd;
  --cs-inline-code-bg: #e9f8fb;
  --cs-content-width: 78ch;
  --cs-shadow: 0 18px 46px rgba(18, 32, 48, .11);
  --cs-radius: 8px;
  --cs-gradient: linear-gradient(135deg, var(--cs-indigo) 0%, var(--cs-blue) 50%, var(--cs-cyan) 100%);
}

[data-bs-theme="dark"] {
  --cs-ink: #edf8fb;
  --cs-heading: #f7fcff;
  --cs-text: #e6f0f6;
  --cs-muted: #a7b7c7;
  --cs-surface: #171921;
  --cs-surface-soft: #10141d;
  --cs-line: #273544;
  --cs-cyan-soft: rgba(22, 199, 221, .14);
  --cs-link: #7ddff5;
  --cs-link-hover: #b5f3ff;
  --cs-table-head-bg: linear-gradient(135deg, #202a55 0%, #164d9f 58%, #0f8aa0 100%);
  --cs-table-row-alt: rgba(22, 199, 221, .08);
  --cs-inline-code-bg: rgba(22, 199, 221, .12);
  --cs-shadow: 0 18px 46px rgba(0, 0, 0, .28);
}

body.cs-learning-page {
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(22, 199, 221, .14), transparent 34rem),
    linear-gradient(180deg, var(--cs-surface-soft) 0%, var(--bs-body-bg) 100%);
  color: var(--cs-ink);
  font-family: var(--cs-font-sans);
  letter-spacing: 0;
}

.cs-public-nav {
  background: color-mix(in srgb, var(--cs-surface) 92%, transparent);
  border-bottom: 1px solid var(--cs-line);
  box-shadow: 0 10px 28px rgba(18, 32, 48, .06);
}

.cs-public-nav .navbar-brand {
  display: inline-flex;
  gap: .55rem;
  align-items: center;
  color: var(--cs-ink);
  font-weight: 800;
}

.cs-public-nav .navbar-brand::before {
  display: none;
}

.cs-public-nav .theme-toggle {
  display: inline-flex;
  width: 36px;
  height: 36px;
  align-items: center;
  justify-content: center;
  padding: 0;
  border-radius: 50%;
}

.cs-public-nav .theme-toggle svg {
  width: 18px;
  height: 18px;
}

.cs-brand-logo {
  display: inline-block;
  width: 38px;
  height: 38px;
  object-fit: contain;
}

.lesson-shell {
  max-width: 1320px;
}

.lesson-list-shell {
  max-width: 1320px;
}

.lesson-page-layout {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

.lesson-list-topic-layout {
  grid-template-columns: 280px minmax(0, 1fr);
}

.lesson-content-column {
  min-width: 0;
}

.lesson-topic-sidebar {
  position: sticky;
  top: 1rem;
  min-width: 0;
  max-height: calc(100vh - 2rem);
  align-self: start;
}

.lesson-topic-sidebar__inner {
  display: flex;
  max-height: calc(100vh - 2rem);
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
  box-shadow: var(--cs-shadow-soft);
}

.lesson-topic-sidebar__header {
  display: flex;
  flex: 0 0 auto;
  gap: .75rem;
  align-items: flex-start;
  justify-content: space-between;
  padding: 1rem;
  border-bottom: 1px solid var(--cs-line);
}

.lesson-topic-sidebar__eyebrow,
.lesson-topic-nav-mobile__label {
  display: block;
  margin-bottom: .2rem;
  color: var(--cs-muted);
  font-size: .75rem;
  font-weight: 750;
  text-transform: uppercase;
}

.lesson-topic-sidebar__header h2 {
  margin: 0;
  color: var(--cs-heading);
  font-size: 1.05rem;
  font-weight: 800;
  line-height: 1.3;
}

.lesson-topic-nav-count {
  display: inline-flex;
  min-width: 1.75rem;
  min-height: 1.75rem;
  align-items: center;
  justify-content: center;
  padding: .15rem .45rem;
  border-radius: 999px;
  background: var(--cs-cyan-soft);
  color: var(--cs-link);
  font-size: .78rem;
  font-weight: 800;
}

.lesson-topic-nav-list {
  min-height: 0;
  overflow-y: auto;
  padding: .45rem;
  scrollbar-gutter: stable;
}

.lesson-topic-nav-group + .lesson-topic-nav-group {
  margin-top: .55rem;
  padding-top: .7rem;
  border-top: 1px solid var(--cs-line);
}

.lesson-topic-nav-group h2,
.lesson-topic-nav-group h3 {
  margin: 0;
  padding: .35rem .55rem .45rem;
  color: var(--cs-muted);
  font-size: .78rem;
  font-weight: 800;
  line-height: 1.35;
  text-transform: uppercase;
}

.lesson-topic-nav-group ol {
  display: grid;
  gap: .18rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lesson-topic-nav-group a {
  display: grid;
  grid-template-columns: 1.6rem minmax(0, 1fr);
  gap: .5rem;
  align-items: start;
  padding: .48rem .55rem;
  border-left: 3px solid transparent;
  border-radius: 5px;
  color: var(--cs-ink);
  font-size: .88rem;
  font-weight: 600;
  line-height: 1.35;
  text-decoration: none;
}

.lesson-topic-nav-group a:hover,
.lesson-topic-nav-group a:focus-visible {
  background: var(--cs-cyan-soft);
  color: var(--cs-link-hover);
}

.lesson-topic-nav-group a.is-current {
  border-left-color: var(--cs-cyan);
  background: var(--cs-cyan-soft);
  color: var(--cs-link);
  font-weight: 800;
}

.lesson-topic-nav-order {
  color: var(--cs-muted);
  font-size: .72rem;
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.lesson-topic-sidebar__all {
  flex: 0 0 auto;
  padding: .8rem 1rem;
  border-top: 1px solid var(--cs-line);
  color: var(--cs-link);
  font-size: .85rem;
  font-weight: 750;
  text-align: center;
  text-decoration: none;
}

.lesson-topic-sidebar__all:hover,
.lesson-topic-sidebar__all:focus-visible {
  background: var(--cs-cyan-soft);
  color: var(--cs-link-hover);
}

.lesson-topic-nav-mobile {
  display: none;
  overflow: hidden;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
}

.lesson-topic-nav-mobile summary {
  display: flex;
  gap: .75rem;
  align-items: center;
  justify-content: space-between;
  padding: .85rem 1rem;
  cursor: pointer;
  color: var(--cs-heading);
  list-style: none;
}

.lesson-topic-nav-mobile summary::-webkit-details-marker {
  display: none;
}

.lesson-topic-nav-mobile[open] summary {
  border-bottom: 1px solid var(--cs-line);
}

.lesson-hero {
  padding: 1.25rem 0 .5rem;
}

.lesson-kicker,
.lesson-meta {
  color: var(--cs-muted);
  font-size: .9rem;
  font-weight: 650;
  letter-spacing: .02em;
}

.lesson-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  align-items: center;
}

.lesson-breadcrumb a {
  color: var(--cs-link);
  text-decoration: none;
}

.lesson-breadcrumb a:hover,
.lesson-breadcrumb a:focus-visible {
  color: var(--cs-link-hover);
  text-decoration: underline;
  text-underline-offset: .18em;
}

.lesson-breadcrumb span {
  color: var(--cs-muted);
}

.lesson-title {
  max-width: 22ch;
  margin: 0;
  color: var(--cs-heading);
  font-size: 2rem;
  font-weight: 850;
  line-height: 1.08;
}

.lesson-subtitle {
  max-width: 62ch;
  color: var(--cs-muted);
}

.lesson-tabs {
  gap: .5rem;
  padding: .35rem;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: color-mix(in srgb, var(--cs-surface) 86%, transparent);
  box-shadow: 0 10px 30px rgba(18, 32, 48, .05);
}

.lesson-tabs .nav-link {
  min-height: 2.5rem;
  border-radius: 6px;
  color: var(--cs-muted);
  font-weight: 700;
}

.lesson-tabs .nav-link:hover,
.lesson-tabs .nav-link:focus-visible {
  color: var(--cs-blue);
  background: var(--cs-cyan-soft);
}

.lesson-tabs .nav-link.active {
  background: var(--cs-gradient);
  color: #fff;
  box-shadow: 0 10px 24px rgba(22, 146, 221, .26);
}

.lesson-panel,
.lesson-card {
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
  box-shadow: var(--cs-shadow);
}

.lesson-panel-body {
  padding: 2.15rem;
}

.lesson-card {
  display: flex;
  height: 100%;
  min-height: 100%;
  flex-direction: column;
  gap: .75rem;
  padding: 1.05rem;
  transition: border-color .18s ease, box-shadow .18s ease, transform .18s ease;
}

.lesson-card:hover {
  border-color: color-mix(in srgb, var(--cs-cyan) 58%, var(--cs-line));
  box-shadow: 0 18px 42px rgba(22, 146, 221, .16);
  transform: translateY(-2px);
}

.lesson-card-title {
  color: var(--cs-ink);
  font-weight: 800;
  line-height: 1.25;
}

.lesson-card-text {
  color: var(--cs-muted);
  font-size: .95rem;
  line-height: 1.55;
}

.lesson-action {
  align-self: flex-start;
  margin-top: auto;
}

.lesson-body {
  max-width: var(--cs-content-width);
  margin: 0 auto;
  color: var(--cs-text);
  font-size: 1.125rem;
  line-height: 1.78;
}

.lesson-body > *:first-child {
  margin-top: 0;
}

.lesson-body > *:last-child {
  margin-bottom: 0;
}

.lesson-body h1,
.lesson-body h2,
.lesson-body h3,
.lesson-body h4 {
  margin: 2.25rem 0 .8rem;
  color: var(--cs-heading);
  font-weight: 850;
  line-height: 1.16;
}

.lesson-body h1 {
  font-size: 2.1rem;
  letter-spacing: 0;
}

.lesson-body h2 {
  padding-left: .85rem;
  border-left: .25rem solid var(--cs-cyan);
  font-size: 1.65rem;
  letter-spacing: 0;
}

.lesson-body h3 {
  margin-top: 1.8rem;
  color: color-mix(in srgb, var(--cs-heading) 82%, var(--cs-blue));
  font-size: 1.35rem;
  letter-spacing: 0;
}

.lesson-body h4 {
  color: var(--cs-link);
  font-size: 1.1rem;
  letter-spacing: 0;
}

.lesson-body p {
  margin: 0 0 1.12rem;
  hyphens: auto;
  overflow-wrap: break-word;
  text-align: justify;
}

.lesson-body a {
  color: var(--cs-link);
  font-weight: 700;
  text-decoration-color: color-mix(in srgb, var(--cs-cyan) 70%, transparent);
  text-decoration-thickness: .12em;
  text-underline-offset: .18em;
}

.lesson-body a:hover {
  color: var(--cs-link-hover);
}

.lesson-body a:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--cs-cyan) 55%, transparent);
  outline-offset: 3px;
  border-radius: 4px;
}

.lesson-body strong {
  color: color-mix(in srgb, var(--cs-heading) 88%, var(--cs-blue));
  font-weight: 800;
}

.lesson-body ul,
.lesson-body ol {
  margin: 0 0 1.25rem;
  padding-left: 1.45rem;
}

.lesson-body li {
  margin: .48rem 0;
  padding-left: .18rem;
}

.lesson-body li::marker {
  color: var(--cs-cyan);
  font-weight: 800;
}

.lesson-body blockquote {
  margin: 1.55rem 0;
  padding: 1.05rem 1.2rem;
  border-left: .3rem solid var(--cs-cyan);
  border-radius: 0 var(--cs-radius) var(--cs-radius) 0;
  background: var(--cs-cyan-soft);
  color: color-mix(in srgb, var(--cs-text) 84%, var(--cs-blue));
  font-weight: 650;
}

.lesson-body table {
  width: 100%;
  margin: 1.65rem 0;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
  font-size: 1rem;
  line-height: 1.55;
}

.lesson-body th,
.lesson-body td {
  padding: .82rem .95rem;
  border-right: 1px solid var(--cs-line);
  border-bottom: 1px solid var(--cs-line);
  vertical-align: top;
}

.lesson-body th:last-child,
.lesson-body td:last-child {
  border-right: 0;
}

.lesson-body tr:last-child > th,
.lesson-body tr:last-child > td {
  border-bottom: 0;
}

.lesson-body th {
  background: var(--cs-table-head-bg);
  color: #fff;
  font-weight: 800;
}

.lesson-body tbody tr:nth-child(even) td {
  background: var(--cs-table-row-alt);
}

.lesson-body tbody tr:hover td {
  background: color-mix(in srgb, var(--cs-cyan-soft) 72%, transparent);
}

.lesson-body figure {
  margin: 1.6rem 0;
}

.lesson-body .lesson-image--50 {
  max-width: 50%;
}

.lesson-body .lesson-image--100 {
  max-width: 100%;
}

.lesson-body .lesson-align-left {
  text-align: left;
}

.lesson-body .lesson-align-center {
  text-align: center;
}

.lesson-body .lesson-align-right {
  text-align: right;
}

.lesson-body .lesson-align-justify {
  text-align: justify;
}

.lesson-body figure.lesson-align-left {
  margin-right: auto;
}

.lesson-body figure.lesson-align-center {
  margin-left: auto;
  margin-right: auto;
}

.lesson-body figure.lesson-align-right {
  margin-left: auto;
}

.lesson-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--cs-radius);
  box-shadow: 0 12px 32px rgba(18, 32, 48, .13);
}

.lesson-body figcaption {
  margin-top: .6rem;
  color: var(--cs-muted);
  font-size: .92rem;
}

.lesson-body code {
  padding: .12rem .34rem;
  border: 1px solid color-mix(in srgb, var(--cs-cyan) 28%, var(--cs-line));
  border-radius: 6px;
  background: var(--cs-inline-code-bg);
  color: color-mix(in srgb, var(--cs-indigo) 72%, var(--cs-heading));
  font-family: var(--cs-font-mono);
  font-variant-ligatures: none;
  font-feature-settings: "liga" 0, "calt" 0;
  font-size: .88em;
}

.lesson-body .lesson-code-block {
  position: relative;
  margin: 1.6rem 0;
  padding: 1rem;
  overflow-x: auto;
  border: 1px solid #293746;
  border-radius: var(--cs-radius);
  background: #0d1117;
  color: #d6deeb;
  font-size: .92rem;
  line-height: 1.58;
  box-shadow: 0 16px 34px rgba(0, 0, 0, .22);
}

.lesson-body .lesson-code-block + p,
.lesson-body table + p,
.lesson-body figure + p {
  margin-top: 1.1rem;
}

.lesson-body .lesson-code-block code {
  display: block;
  padding: 0;
  border: 0;
  background: transparent;
  color: inherit;
  font-family: var(--cs-font-mono);
  font-variant-ligatures: none;
  font-feature-settings: "liga" 0, "calt" 0;
  white-space: pre;
}

.lesson-body .code-comment {
  color: #7d8590;
}

.lesson-body .code-string {
  color: #a5d6ff;
}

.lesson-body .code-keyword {
  color: #ff7b72;
}

.lesson-body .code-number {
  color: #79c0ff;
}

.lesson-body .code-tag {
  color: #7ee787;
}

.lesson-keywords {
  border-top: 1px solid var(--cs-line);
}

.lesson-section-title {
  color: var(--cs-ink);
  font-weight: 800;
}

.lesson-muted {
  color: var(--cs-muted);
}

.lesson-video-frame {
  aspect-ratio: 16 / 9;
  width: 100%;
  border: 0;
  border-radius: var(--cs-radius);
  background: #000;
  box-shadow: 0 14px 34px rgba(18, 32, 48, .16);
}

.lesson-share-qr {
  width: 220px;
  max-width: 100%;
  padding: .5rem;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: #fff;
}

.lesson-share-qr svg {
  display: block;
  width: 100%;
  height: auto;
}

.lesson-share-box {
  white-space: pre-wrap;
}

.lesson-resource-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr));
  gap: 1rem;
}

.lesson-resource-card {
  display: flex;
  min-width: 0;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
  color: var(--cs-ink);
}

.lesson-resource-preview {
  display: block;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border-bottom: 1px solid var(--cs-line);
  background: color-mix(in srgb, var(--cs-surface) 82%, var(--cs-line));
}

.lesson-resource-preview img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.lesson-resource-card__body {
  display: flex;
  min-height: 170px;
  flex: 1;
  flex-direction: column;
  gap: .85rem;
  padding: 1rem;
}

.lesson-resource-card__body .btn {
  margin-top: auto;
}

.learning-home-shell {
  max-width: 1180px;
}

.learning-home-title {
  color: var(--cs-ink);
  font-weight: 850;
  line-height: 1.08;
}

.learning-home-brand {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.learning-home-brand .learning-home-logo {
  width: 48px;
  height: 48px;
  object-fit: contain;
  filter: drop-shadow(0 12px 24px rgba(18, 32, 48, .16));
}

.learning-home-grid {
  align-items: stretch;
}

.learning-home-card {
  display: flex;
  min-height: 100%;
  flex-direction: column;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
  box-shadow: var(--cs-shadow);
}

.learning-home-card__header {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  justify-content: space-between;
  padding: 1.15rem 1.15rem .75rem;
  border-bottom: 1px solid var(--cs-line);
}

.learning-home-card__title {
  margin: 0;
  color: var(--cs-ink);
  font-weight: 820;
}

.learning-home-card__meta {
  color: var(--cs-muted);
  font-size: .92rem;
}

.learning-count {
  min-width: 3rem;
  padding: .32rem .6rem;
  border-radius: 999px;
  background: var(--cs-gradient);
  color: #fff;
  font-weight: 850;
  text-align: center;
}

.learning-home-list {
  display: grid;
  gap: .75rem;
  padding: 1rem 1.15rem;
}

.learning-home-list--grouped {
  gap: 1rem;
}

.learning-topic-group,
.lesson-topic-section {
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: color-mix(in srgb, var(--cs-surface) 90%, var(--cs-surface-soft));
}

.learning-topic-header,
.lesson-topic-header {
  display: flex;
  gap: .75rem;
  align-items: center;
  justify-content: space-between;
  padding: .78rem .9rem;
  border-bottom: 1px solid var(--cs-line);
}

.learning-topic-title,
.lesson-topic-title {
  margin: 0;
  color: var(--cs-ink);
  font-size: .98rem;
  font-weight: 820;
  line-height: 1.25;
}

.learning-topic-count,
.lesson-topic-count {
  min-width: 2.1rem;
  padding: .18rem .5rem;
  border-radius: 999px;
  background: var(--cs-cyan-soft);
  color: color-mix(in srgb, var(--cs-blue) 75%, var(--cs-ink));
  font-size: .82rem;
  font-weight: 820;
  text-align: center;
}

.learning-topic-items {
  display: grid;
  gap: .6rem;
  padding: .75rem;
}

.lesson-topic-section {
  padding: 0;
}

.lesson-topic-body {
  padding: 1rem;
}

.lesson-subtopic-section {
  padding: .9rem;
  border: 1px solid var(--cs-line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--cs-surface) 84%, var(--cs-surface-soft));
}

.lesson-subtopic-header {
  display: flex;
  gap: .75rem;
  align-items: center;
  justify-content: space-between;
  margin-bottom: .85rem;
}

.lesson-subtopic-title {
  margin: 0;
  color: var(--cs-ink);
  font-size: .95rem;
  font-weight: 820;
}

.lesson-card-order {
  align-self: flex-start;
  min-width: 2.25rem;
  padding: .14rem .45rem;
  border-radius: 999px;
  background: var(--cs-cyan-soft);
  color: color-mix(in srgb, var(--cs-blue) 72%, var(--cs-ink));
  font-size: .8rem;
  font-weight: 820;
  text-align: center;
}

.learning-home-item {
  display: block;
  padding: .85rem;
  border: 1px solid var(--cs-line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--cs-surface) 86%, var(--cs-surface-soft));
  color: var(--cs-ink);
  text-decoration: none;
}

.learning-home-item:hover,
.learning-home-item:focus-visible {
  border-color: color-mix(in srgb, var(--cs-cyan) 58%, var(--cs-line));
  background: var(--cs-cyan-soft);
}

.learning-home-item__title {
  color: var(--cs-ink);
  font-weight: 780;
  line-height: 1.3;
}

.learning-home-item__eyebrow {
  color: var(--cs-muted);
  font-size: .75rem;
  font-weight: 700;
  margin-bottom: .2rem;
}

.learning-home-item__text {
  color: var(--cs-muted);
  font-size: .9rem;
  line-height: 1.45;
}

.learning-home-card__footer {
  margin-top: auto;
  padding: 0 1.15rem 1.15rem;
}

.learning-empty {
  margin: 1rem 1.15rem;
  padding: 1rem;
  border: 1px dashed var(--cs-line);
  border-radius: 8px;
  color: var(--cs-muted);
}

.test-shell {
  max-width: 1020px;
}

.test-start-grid,
.test-result-summary,
.test-submit-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 1.2rem;
  align-items: center;
}

.test-meta-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: .75rem;
}

.test-meta-grid > div {
  padding: .85rem;
  border: 1px solid var(--cs-line);
  border-radius: 8px;
  background: var(--cs-surface-soft);
}

.test-meta-grid span {
  display: block;
  color: var(--cs-muted);
  font-size: .82rem;
  font-weight: 720;
  text-transform: uppercase;
}

.test-meta-grid strong {
  display: block;
  margin-top: .18rem;
  color: var(--cs-ink);
  font-size: 1.02rem;
}

.test-start-action {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: .65rem;
}

.test-result-percent {
  min-width: 6.5rem;
  padding: .7rem .9rem;
  border-radius: 8px;
  background: var(--cs-gradient);
  color: #fff;
  font-size: 1.55rem;
  font-weight: 860;
  text-align: center;
}

.test-progress-panel {
  position: sticky;
  top: .75rem;
  z-index: 5;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(160px, 260px);
  gap: 1rem;
  align-items: center;
  margin-bottom: 1rem;
  padding: .85rem 1rem;
  border: 1px solid var(--cs-line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--cs-surface) 94%, transparent);
  box-shadow: var(--cs-shadow-soft);
  backdrop-filter: blur(10px);
}

.test-progress-track {
  height: .55rem;
  overflow: hidden;
  border-radius: 999px;
  background: var(--cs-surface-soft);
}

.test-progress-fill {
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--cs-gradient);
  transition: width .18s ease;
}

.test-question-list {
  display: grid;
  gap: 1rem;
}

.test-question-card {
  padding: 1.2rem;
  border: 1px solid var(--cs-line);
  border-radius: var(--cs-radius);
  background: var(--cs-surface);
  box-shadow: var(--cs-shadow-soft);
}

.test-question-card.is-correct {
  border-color: color-mix(in srgb, #18a058 52%, var(--cs-line));
}

.test-question-card.is-wrong {
  border-color: color-mix(in srgb, #e05d5d 50%, var(--cs-line));
}

.test-question-head {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: .95rem;
}

.test-question-head h2,
.test-question-head h3 {
  margin: 0;
  color: var(--cs-ink);
  font-size: 1.16rem;
  font-weight: 820;
  line-height: 1.42;
}

.test-point-badge,
.test-question-status {
  flex: 0 0 auto;
  padding: .22rem .55rem;
  border: 1px solid var(--cs-line);
  border-radius: 999px;
  background: var(--cs-surface-soft);
  color: var(--cs-muted);
  font-size: .82rem;
  font-weight: 760;
}

.test-answer-grid {
  display: grid;
  gap: .68rem;
}

.answer-card {
  position: relative;
  display: flex;
  gap: .75rem;
  align-items: flex-start;
  min-height: 3.25rem;
  margin: 0;
  padding: .82rem .9rem;
  border: 1px solid var(--cs-line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--cs-surface) 88%, var(--cs-surface-soft));
  color: var(--cs-ink);
  cursor: pointer;
  transition: border-color .16s ease, background-color .16s ease, box-shadow .16s ease, opacity .16s ease;
}

.answer-card:hover,
.answer-card:focus-within {
  border-color: color-mix(in srgb, var(--cs-cyan) 56%, var(--cs-line));
  box-shadow: 0 0 0 .18rem color-mix(in srgb, var(--cs-cyan) 12%, transparent);
}

.answer-card.is-selected,
.answer-card:has(.answer-card__input:checked) {
  border-color: color-mix(in srgb, var(--cs-cyan) 72%, var(--cs-blue));
  background: var(--cs-cyan-soft);
}

.answer-card.is-disabled {
  cursor: not-allowed;
  opacity: .54;
}

.answer-card.is-correct-answer {
  border-color: color-mix(in srgb, #18a058 54%, var(--cs-line));
}

.test-question-card.is-wrong .answer-card.is-selected:not(.is-correct-answer) {
  border-color: color-mix(in srgb, #e05d5d 58%, var(--cs-line));
}

.answer-card__input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.answer-card__marker {
  flex: 0 0 auto;
  width: 1.18rem;
  height: 1.18rem;
  margin-top: .12rem;
  border: 2px solid color-mix(in srgb, var(--cs-muted) 48%, var(--cs-line));
  border-radius: 999px;
  background: var(--cs-surface);
}

.answer-card:has(.answer-card__input[type="checkbox"]) .answer-card__marker {
  border-radius: 5px;
}

.answer-card.is-selected .answer-card__marker,
.answer-card:has(.answer-card__input:checked) .answer-card__marker {
  border-color: transparent;
  background: var(--cs-gradient);
  box-shadow: inset 0 0 0 4px var(--cs-surface);
}

.answer-card__text {
  min-width: 0;
  color: var(--cs-ink);
  font-size: 1rem;
  line-height: 1.45;
}

.test-help,
.test-explanation {
  margin-top: .85rem;
  color: var(--cs-muted);
  font-size: .92rem;
  line-height: 1.5;
}

.test-explanation {
  padding: .85rem;
  border-left: 3px solid var(--cs-cyan);
  border-radius: 8px;
  background: var(--cs-cyan-soft);
}

.test-submit-panel {
  position: sticky;
  bottom: .75rem;
  z-index: 5;
  margin-top: 1rem;
  padding: .85rem 1rem;
  border: 1px solid var(--cs-line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--cs-surface) 94%, transparent);
  box-shadow: var(--cs-shadow-soft);
  backdrop-filter: blur(10px);
}

@media (max-width: 700px) {
  .learning-home-brand {
    align-items: flex-start;
  }

  .learning-home-brand .learning-home-logo {
    width: 44px;
    height: 44px;
  }

  .lesson-tabs {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .lesson-tabs .nav-item,
  .lesson-tabs .nav-link {
    width: 100%;
  }

  .lesson-body {
    font-size: 1.03rem;
    line-height: 1.72;
  }

  .lesson-body p {
    hyphens: manual;
    text-align: left;
  }

  .lesson-panel-body {
    padding: 1.25rem;
  }

  .lesson-title {
    font-size: 1.65rem;
  }

  .lesson-body h1 {
    font-size: 1.72rem;
  }

  .lesson-body h2 {
    font-size: 1.38rem;
  }

  .lesson-body h3 {
    font-size: 1.18rem;
  }

  .lesson-body h1,
  .lesson-body h2,
  .lesson-body h3,
  .lesson-body h4 {
    margin-top: 1.8rem;
  }

  .lesson-body .lesson-image--50 {
    max-width: 100%;
  }

  .lesson-body table {
    display: block;
    overflow-x: auto;
    max-width: 100%;
    white-space: nowrap;
  }

  .lesson-body th,
  .lesson-body td {
    padding: .7rem .78rem;
  }

  .test-start-grid,
  .test-result-summary,
  .test-submit-panel,
  .test-progress-panel {
    grid-template-columns: 1fr;
  }

  .test-meta-grid {
    grid-template-columns: 1fr;
  }

  .test-start-action {
    justify-content: stretch;
  }

  .test-start-action .btn,
  .test-submit-panel .btn {
    width: 100%;
  }

  .test-question-head {
    display: grid;
  }

  .test-point-badge,
  .test-question-status {
    justify-self: start;
  }
}

@media (max-width: 991.98px) {
  .lesson-page-layout {
    display: block;
  }

  .lesson-topic-sidebar {
    display: none;
  }

  .lesson-topic-nav-mobile {
    display: block;
  }

  .lesson-topic-nav-mobile .lesson-topic-nav-list {
    max-height: min(60vh, 34rem);
  }
}