/* The original learner design tokens live in the compiled shared stylesheet. */
:root {
  --muted: var(--ink-muted);
  --danger: var(--bad);
}
body {
  margin: 0;
  background: var(--fog);
  color: var(--ink);
  font-family: var(--font-body), sans-serif;
  line-height: 1.7;
}
html[dir="rtl"] body {
  font-family: var(--font-arabic-ui), sans-serif;
}
button,
input,
summary {
  font: inherit;
}
button,
summary {
  cursor: pointer;
}
button:disabled {
  opacity: 0.55;
  cursor: wait;
}
button:focus-visible,
a:focus-visible,
summary:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 4px;
}
.site-header {
  position: relative;
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
  width: 100%;
  padding: 1rem max(1.5rem, calc((100% - 72rem) / 2));
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  z-index: 30;
  font-size: 0.875rem;
}
.site-header .brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink);
  font-family: var(--font-arabic-ui), sans-serif;
  font-size: 1.25rem;
  text-decoration: none;
  white-space: nowrap;
}
.brand img {
  width: 32px;
  height: 34px;
  object-fit: contain;
}
.site-header nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.desktop-nav {
  margin-inline-start: auto;
}
.site-header a:hover {
  text-decoration: underline;
}
.site-header button {
  border: 0;
  background: transparent;
  color: var(--link);
  padding: 0.25rem;
}
.skip-link {
  position: fixed;
  top: -10rem;
  z-index: 100;
  background: var(--surface);
  padding: 1rem;
}
.skip-link:focus {
  top: 0;
}
.mobile-nav {
  display: none;
}
.explore-menu summary {
  list-style: none;
  color: var(--ink);
}
.explore-panel {
  position: absolute;
  inset-inline-start: 1.5rem;
  top: 100%;
  width: min(38rem, calc(100vw - 3rem));
  padding: 1.25rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  box-shadow: 0 8px 30px #0002;
}
.explore-panel label {
  display: block;
}
.explore-panel input {
  width: 100%;
  margin: 0.5rem 0;
  padding: 0.6rem;
  border: 1px solid var(--line);
  border-radius: 0.4rem;
  background: var(--fog);
  color: var(--ink);
}
.explore-panel ul {
  max-height: 50vh;
  overflow: auto;
  list-style: none;
  padding: 0;
}
.explore-panel li a {
  display: block;
  padding: 0.4rem;
  border-radius: 0.3rem;
}
.explore-panel li a:hover {
  background: var(--fog);
}
.explore-panel li > details > summary {
  padding: 0.5rem;
  border-radius: 0.4rem;
  list-style: none;
}
.explore-panel li > details > summary::before {
  content: "▸";
  display: inline-block;
  margin-inline-end: 0.5rem;
}
.explore-panel li > details:not([open]) > summary:dir(rtl)::before {
  content: "◂";
}
.explore-panel li > details[open] > summary::before {
  content: "▾";
}
.explore-panel li > details > summary:hover {
  background: var(--link-soft);
}
.explore-panel details ul {
  max-height: none;
  overflow: visible;
  margin-inline-start: 1rem;
  padding-inline-start: 0.75rem;
  border-inline-start: 1px solid var(--line);
}
.catalog-page {
  max-width: 60rem;
  margin: auto;
  padding: 3rem 1.5rem 5rem;
}
.catalog-page h1 {
  font-family: var(--font-display);
  font-size: 2.15rem;
  line-height: 1.5;
}
.catalog-page h2 {
  font-size: 1.2rem;
  margin: 2rem 0 1rem;
}
.catalog-page h3 {
  font-weight: 600;
  font-size: 1.1rem;
}
.lead,
.muted {
  color: var(--ink-muted);
}
.lead {
  max-width: 45rem;
  margin: 1rem 0 2rem;
}
.landing-page {
  background: var(--surface);
}
.landing-page h1 {
  font-family: inherit;
}
.course-explorer {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin-top: 2rem;
  padding: 0;
}
.course-explorer a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--ink);
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--surface);
  height: 100%;
}
.course-explorer a:hover {
  background: var(--link-soft);
  color: var(--link);
}
.course-code {
  display: grid;
  place-items: center;
  min-width: 3rem;
  height: 3rem;
  padding: 0.3rem;
  border-radius: 0.4rem;
  background: var(--accent-deep);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
}
.dashboard-courses {
  display: grid;
  gap: 1rem;
  list-style: none;
  padding: 0;
}
.course-card {
  border: 1px solid var(--line);
  border-radius: 0.6rem;
  padding: 1.5rem;
  background: var(--surface);
}
.reading-card {
  display: block;
  text-decoration: none;
}
.reading-card:hover {
  border-color: var(--accent);
}
.reading-card:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}
.course-card-title {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--ink);
}
.course-card .muted {
  font-size: 0.9rem;
  margin: 0.5rem 0;
}
.progress-summary {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 1rem 0;
  font-size: 0.85rem;
}
.progress-summary progress {
  max-width: 16rem;
  flex: 1;
  min-width: 8rem;
}
.resume-link {
  display: inline-block;
  margin-top: 0.5rem;
}
progress {
  accent-color: var(--mastery-bar);
  height: 0.65rem;
}
.button {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  padding: 0.65rem 1.1rem;
  background: var(--accent-deep);
  color: #fff;
  border-radius: 0.4rem;
  text-decoration: none;
}
.actions {
  margin: 1.5rem 0;
}
.course-unit {
  margin-top: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--surface);
  padding: 1.25rem;
}
.course-unit summary {
  font-weight: 600;
}
.course-activities {
  padding-inline-start: 1.5rem;
  margin-top: 1rem;
}
.course-activities li {
  padding: 0.55rem 0.25rem;
  border-top: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.course-activities a {
  color: var(--ink);
}
.course-activities a:hover {
  color: var(--link);
}
.badge {
  font-size: 0.75rem;
  color: var(--ok);
}
.course-progress {
  display: flex;
  gap: 1rem;
  align-items: center;
  margin: 1rem 0;
}
.course-objectives {
  padding-inline-start: 1.5rem;
  list-style: disc;
  margin: 1.5rem 0;
}
.auth-page {
  max-width: 30rem !important;
  margin: 4rem auto !important;
  padding: 2rem !important;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  box-shadow: 0 1px 3px #0001;
}
.auth-page.profile {
  max-width: 42rem !important;
}
.auth-page h1 {
  font-size: 1.75rem;
}
.auth-page form {
  margin-top: 1.5rem;
}
.auth-page input {
  background: var(--fog);
  border-color: var(--line);
  color: var(--ink);
}
.auth-page button[type="submit"] {
  background: var(--accent-deep);
  color: #fff;
}
.auth-page .hint,
.auth-page .alt {
  color: var(--ink-muted);
}
.lesson-breadcrumb {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
}
.lesson-mobile-outline {
  display: none;
}
.lesson-completion-control {
  text-align: center;
}
.mark-done-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 2.25rem;
  padding: 0.375rem 0.75rem;
  border-radius: 0.375rem;
  background: var(--link);
  color: white;
  font-size: 0.875rem;
  font-weight: 500;
  white-space: nowrap;
}
.mark-done-button:hover {
  opacity: 0.9;
}
.mark-done-button[data-complete="true"] {
  background: var(--accent-soft);
  color: var(--ink);
}
.mark-done-button[data-complete="true"]:hover {
  background: var(--surface-raised);
}
.completion-status {
  margin-top: 0.5rem;
  font-size: 0.75rem;
  color: var(--ink-muted);
  max-width: 12rem;
}
.completion-status[role="alert"] {
  color: var(--bad);
}
.completion-status:empty {
  display: none;
}
.lesson-sidebar .outline-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1rem;
}
@media (max-width: 800px) {
  .site-header {
    gap: 0.7rem;
    padding: 0.75rem 1rem;
  }
  .site-header:not(.learning-header) .desktop-nav {
    display: none !important;
  }
  .mobile-nav {
    display: block;
    margin-inline-start: auto;
  }
  .mobile-nav nav {
    position: absolute;
    top: 100%;
    inset-inline-end: 1rem;
    background: var(--surface);
    border: 1px solid var(--line);
    padding: 1rem;
    flex-direction: column;
    align-items: stretch;
    min-width: 12rem;
  }
  .course-explorer {
    grid-template-columns: 1fr;
  }
  .catalog-page {
    padding-top: 2rem;
  }
  .auth-page {
    margin: 2rem 1rem !important;
  }
  .site-header .brand span {
    font-size: 1rem;
  }
}

.catalog-page a,
.auth-page a {
  color: var(--link);
}
.lesson-nav-group {
  margin-top: 1rem;
}
.lesson-nav-group summary {
  padding: 0.45rem 0.25rem;
  font-weight: 600;
}
.lesson-nav-group ol {
  margin-top: 0.5rem;
}

/* Match the compact site chrome and reading geometry of the learner app. */
.site-header {
  gap: 0.75rem;
  padding: max(0.75rem, env(safe-area-inset-top)) 1.5rem 0.75rem;
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: blur(8px);
}
.site-header .brand {
  order: 0;
  font-size: 1rem;
}
.site-header .explore-menu {
  order: 1;
}
.site-header .desktop-nav,
.site-header .mobile-nav {
  order: 2;
}
.site-header > button,
.site-header > span {
  order: 3;
}
.site-header nav a {
  color: var(--ink-muted);
  text-decoration: none;
}
.site-header nav a:hover,
.site-header nav a[aria-current] {
  color: var(--ink);
}
.profile-menu summary {
  display: flex;
  padding: 0.4rem;
  list-style: none;
  border-radius: 50%;
}
.profile-menu summary:hover {
  background: var(--link-soft);
}
.profile-panel {
  position: absolute;
  top: 100%;
  inset-inline-end: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  min-width: 12rem;
  padding: 0.5rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  box-shadow: 0 8px 24px #0002;
}
.profile-panel a,
.site-header .profile-panel button {
  padding: 0.5rem 0.75rem;
  text-align: start;
}
.explore-panel .explore-links {
  padding-bottom: 1rem;
}
.dashboard-page {
  max-width: 944px;
}
.course-page {
  max-width: 848px;
}
.dashboard-page h2 {
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: var(--ink-muted);
}
.dashboard-courses {
  gap: 0.75rem;
}
.dashboard-card {
  padding: 0;
  overflow: hidden;
  box-shadow: 0 1px 2px #21242c0f;
}
.dashboard-course-link {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
}
.dashboard-course-info {
  flex: 1;
  min-width: 0;
}
.dashboard-course-info p {
  margin: 0.25rem 0 0;
  font-size: 0.75rem;
}
.dashboard-card .course-card-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--ink);
}
.dashboard-card .progress-summary {
  margin-inline-start: auto;
  font-size: 0.875rem;
  font-weight: 600;
}
.dashboard-card progress {
  width: 4rem;
  accent-color: var(--link);
}
.dashboard-card .resume-link {
  display: block;
  padding: 0.5rem 1rem;
  margin: 0;
  border-top: 1px solid var(--line);
  font-size: 0.8rem;
}
.dashboard-card:has(a:hover) {
  border-color: var(--link);
  background: color-mix(in srgb, var(--link-soft) 40%, var(--surface));
}
html[dir="ltr"] .resume-link span {
  display: inline-block;
  transform: rotate(180deg);
}
.course-page .lead {
  display: none;
}
.course-page .course-objectives {
  font-size: 0.875rem;
  color: var(--ink-muted);
}
.course-page h2 {
  font-size: 0.875rem;
  font-weight: 500;
}
@media (max-width: 600px) {
  .site-header {
    padding-inline: 1rem;
    gap: 0.5rem;
  }
  .site-header .brand span {
    display: none;
  }
  .dashboard-course-link {
    flex-wrap: wrap;
  }
  .dashboard-card .progress-summary {
    width: 100%;
    justify-content: flex-end;
  }
}
@media print {
  .site-header,
  .skip-link,
  .lesson-toolbar,
  .lesson-sidebar,
  .lesson-mobile-outline,
  .lesson-pagination {
    display: none !important;
  }
  .lesson-frame {
    display: block;
    padding: 0;
    max-width: none;
  }
  .lesson-content {
    padding: 0;
  }
}

.course-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}
.course-column,
.course-column-stack {
  min-width: 0;
}
.course-column-stack {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.course-page .course-column h3 {
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.course-column-stack-summary,
.course-column-stack-test,
.course-column-stack-language {
  grid-column: 1 / -1;
}
.course-column-summary,
.course-column-test {
  border-radius: 0.5rem;
  background: var(--fog);
  padding: 0.75rem;
}
.course-column .course-activities {
  padding: 0;
  margin: 0;
  list-style: none;
}
.course-column .course-activities li {
  display: block;
  padding: 0;
  border-top: 0;
}
.course-activity {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  min-height: 3rem;
  padding: 0.6rem 0.25rem;
  font-size: 0.875rem;
  border-radius: 0.5rem;
  transition: background-color 150ms ease;
}
.course-activity:hover,
.course-activity:focus-visible {
  background: var(--link-soft);
}
.course-activity:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}
.lesson-nav-group a {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}
.course-column .course-activities a {
  color: var(--link);
}
.activity-title {
  flex: 1;
  min-width: 0;
}
.activity-duration {
  flex-shrink: 0;
  font-size: 0.75rem;
}
.completion-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
  border: 1px solid var(--ink-muted);
  border-radius: 50%;
  font-size: 0.65rem;
}
.completion-mark.is-complete,
.completion-mark:has([data-completion-mark]:not([hidden])) {
  background: var(--link);
  border-color: var(--link);
  color: var(--fog);
}
.auth-entry {
  max-width: 28rem !important;
  margin: max(4rem, calc((100dvh - 38rem) / 2)) auto 4rem !important;
  padding: 0 1.5rem !important;
  background: transparent;
  border: 0;
  border-radius: 0;
  box-shadow: none;
}
.auth-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink) !important;
  font-family: var(--font-arabic-ui);
  font-size: 1.25rem;
  text-decoration: none;
  margin-bottom: 2rem;
}
.auth-entry h1 {
  font-size: 1.5rem;
  font-weight: 600;
}
.auth-entry form {
  margin-top: 2rem;
}
.auth-entry input {
  background: var(--surface);
}
.auth-entry button[type="submit"] {
  background: var(--ink);
  color: var(--fog);
}
.auth-entry button[type="submit"]:hover {
  background: var(--accent-deep);
}
@media (max-width: 600px) {
  .course-columns {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  .activity-duration {
    max-width: 6rem;
    text-align: end;
  }
  .auth-entry {
    margin: 4rem auto !important;
  }
}

.site-header .header-search {
  order: 0;
  width: 11rem;
  min-width: 0;
  padding: 0.4rem 0.65rem;
  border: 1px solid var(--line);
  border-radius: 0.4rem;
  background: var(--fog);
  color: var(--ink);
  font-size: 0.75rem;
}
@media (max-width: 1023px) {
  .site-header .header-search {
    width: 8rem;
  }
}
@media (max-width: 600px) {
  .site-header .header-search {
    width: 6rem;
  }
}

.catalog-page a.button {
  color: #fff;
}
.course-column-stack-practice,
.course-column-stack-coding {
  grid-column: 2;
}
@media (max-width: 600px) {
  .course-column-stack-practice,
  .course-column-stack-coding {
    grid-column: auto;
  }
}

.lesson-feedback-button {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  min-height: 2.25rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  padding: 0.375rem 0.625rem;
  background: var(--surface);
  color: var(--ink);
  font-size: 0.875rem;
  font-weight: 600;
  white-space: nowrap;
  box-shadow: 0 1px 2px #0000000d;
  transition:
    background-color 150ms,
    border-color 150ms;
}
.lesson-feedback-button:hover {
  background: var(--link-soft);
  border-color: var(--link);
}
.lesson-feedback-button[aria-busy="true"] {
  opacity: 0.6;
  cursor: wait;
}
@media (max-width: 900px) {
  .lesson-tools {
    flex-wrap: wrap;
  }
}

.duration-icons {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.125em;
  margin-inline-end: 0.25em;
  vertical-align: -0.125em;
}
.duration-icons svg {
  width: 1.2em;
  height: 1.2em;
  flex-shrink: 0;
}
.lesson-meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  max-width: 720px;
  margin: 0 auto;
  padding-bottom: 0.75rem;
  font-size: 0.875rem;
  color: var(--ink-muted);
}
.lesson-meta-row [data-print-lesson] {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  margin-inline-start: auto;
  text-decoration: underline;
}
[data-print-lesson] svg {
  width: 1rem;
  height: 1rem;
}
@media print {
  [data-learn-content] .learn-panel {
    max-width: none !important;
    border: 0 !important;
    box-shadow: none !important;
    padding: 0 !important;
    background: white !important;
  }
}

#learn-header-report {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.course-duration .duration-clock.is-complete { color: var(--ok); }
.course-activity > .activity-duration {
  text-align: start;
  white-space: nowrap;
}


.course-learning-summary {
  margin-block: 1.5rem 2rem;
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: var(--surface);
}
.course-progress-summary {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1.25rem 3rem;
}
.course-activity-progress {
  flex: 1 1 15rem;
  display: grid;
  gap: 0.75rem;
}
.course-progress-track {
  appearance: none;
  display: block;
  width: 100%;
  height: 0.5rem;
  border: 0;
  border-radius: 1rem;
  overflow: hidden;
  background: var(--fog);
  accent-color: var(--link);
}
.course-progress-track::-webkit-progress-bar { background: var(--fog); }
.course-progress-track::-webkit-progress-value { background: var(--link); border-radius: 1rem; }
.course-progress-track::-moz-progress-bar { background: var(--link); border-radius: 1rem; }
.course-time-summary { display: grid; gap: 0.25rem; }
.course-time-summary > .muted { font-size: 0.875rem; }
.course-time-summary > strong { font-size: 1.125rem; }
.course-resume {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-block-start: 1.25rem;
  padding-block-start: 1.25rem;
  border-block-start: 1px solid var(--line);
}
.course-resume .button {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: 100%;
  text-align: start;
  line-height: 1.6;
}
.catalog-page .course-resume a.course-playground { background: transparent; color: var(--link); border: 1px solid var(--link); }
.course-resume svg { width: 1.25rem; height: 1.25rem; flex-shrink: 0; }
[dir="ltr"] .course-resume .button:not(.course-playground) svg { transform: rotate(180deg); }
@media (max-width: 600px) {
  .course-learning-summary { padding: 1.25rem; }
  .course-progress-summary { align-items: stretch; gap: 1.25rem; }
  .course-time-summary { flex-basis: 100%; }
  .course-resume .button { display: flex; }
}
.course-duration {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.75rem;
  width: fit-content;
  max-width: 100%;
  margin-block: 0.5rem 0;
}
.course-duration > bdi {
  order: -1;
  font-size: 0.95rem;
  font-weight: 600;
}
.course-duration > .duration-icons {
  display: flex;
  flex-wrap: wrap;
  max-width: 14rem;
  gap: 0.5rem;
  direction: rtl;
  margin: 0;
  padding: 0.875rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: var(--surface);
}
.course-duration .duration-icons svg {
  width: 1.5rem;
  height: 1.5rem;
}
@media (max-width: 400px) {
  .course-duration { width: 100%; }
  .course-duration > .duration-icons {
    box-sizing: border-box;
    width: 100%;
    grid-template-columns: repeat(8, minmax(0, 1fr));
  }
  .course-duration .duration-icons svg {
    width: 100%;
    max-width: 1.5rem;
  }
}

/* Keep keyboard focus visible inside scrolling learner panels. */
[data-learn-page] :focus-visible {
  outline: 2px solid var(--link);
  outline-offset: -2px;
  scroll-margin-block: 1rem;
}
.lesson-mobile-outline summary { overflow-wrap: anywhere; }
.lesson-mobile-outline a[aria-current="page"] { font-weight: 700; }

/* Standalone challenge skill tree. Native disclosures work without JavaScript. */
.challenges-page {
  max-width: 1120px;
  margin-inline: auto;
  padding-bottom: 5rem;
}
.challenge-eyebrow {
  color: var(--link, #7362c4);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}
.challenge-intro {
  max-width: 44rem;
  line-height: 1.9;
  color: var(--muted, #777);
}
.challenge-tree,
.challenge-tree ul {
  list-style: none;
  padding: 0;
}
.challenge-tree {
  margin-top: 2.5rem;
}
.challenge-tree ul {
  margin-inline-start: 1.25rem;
  padding-inline-start: 1.5rem;
  border-inline-start: 1px solid var(--border, #aaa5);
  margin-top: 1.25rem;
}
.challenge-tree li {
  position: relative;
  margin-block: 1rem;
}
.challenge-tree ul > li::before {
  content: "";
  position: absolute;
  inset-inline-start: -1.5rem;
  top: 1.5rem;
  width: 1.5rem;
  border-top: 1px solid var(--border, #aaa5);
}
.challenge-tree summary {
  cursor: pointer;
  border: 1px solid #8b71d477;
  border-radius: 14px;
  padding: 1rem 1.25rem;
  background: color-mix(in srgb, #8b71d4 12%, var(--surface, #fff));
  font-weight: 600;
}
.challenge-count {
  font-size: 0.8rem;
  font-weight: 400;
  margin-inline-start: 1rem;
  color: var(--muted, #777);
}
.challenge-tree progress {
  display: block;
  width: min(100%, 15rem);
  height: 6px;
  margin-top: 0.8rem;
  accent-color: #20b984;
}
.challenge-leaf a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.25rem;
  border: 1px solid var(--border, #aaa5);
  border-radius: 12px;
  color: inherit;
  text-decoration: none;
  background: var(--surface, #fff);
}
.challenge-leaf a:hover {
  border-color: #8b71d4;
  background: color-mix(
    in srgb,
    var(--accent, #7860b8) 6%,
    var(--surface, #fff)
  );
}
.challenge-status {
  font-size: 0.8rem;
  color: var(--muted, #777);
  white-space: nowrap;
}
@media (min-width: 760px) {
  .challenge-tree > li > details > ul {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 2rem;
  }
}
@media (max-width: 480px) {
  .challenge-tree ul {
    margin-inline-start: 0.25rem;
    padding-inline-start: 0.8rem;
  }
  .challenge-tree ul > li::before {
    inset-inline-start: -0.8rem;
    width: 0.8rem;
  }
  .challenge-leaf a {
    align-items: start;
    flex-direction: column;
  }
  .challenge-count {
    display: block;
    margin-inline-start: 0;
    margin-top: 0.4rem;
  }
}

.course-coming-soon { opacity: .5; }
.course-coming-soon[aria-disabled="true"] { cursor: default; pointer-events: none; }
.coming-soon-label { display: block; font-size: .85em; }

/* One discovery menu on small screens; search gets the full panel width. */
.site-header .explore-panel .header-search {
  width: 100%;
  font-size: 1rem;
  min-height: 44px;
}
.explore-menu > summary {
  min-height: 44px;
  display: flex;
  align-items: center;
}
.explore-account {
  display: none;
}
@media (max-width: 800px) {
  .site-header:not(.learning-header) .mobile-nav {
    display: none;
  }
  .site-header:not(.learning-header) .brand {
    order: 0;
    margin-inline-end: 0;
  }
  .site-header:not(.learning-header) .explore-menu {
    order: 1;
  }
  .explore-panel {
    max-height: calc(100dvh - 6rem);
    overflow-y: auto;
  }
  .site-header .explore-links {
    flex-wrap: wrap;
  }
  .explore-account {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    padding-block: 0.75rem;
    border-bottom: 1px solid var(--line);
  }
}
.lesson-help-disclosure {
  position: relative;
}
.lesson-help-disclosure > summary {
  cursor: pointer;
  padding: 0.6rem;
}
.lesson-help-panel {
  position: absolute;
  inset-inline-end: 0;
  top: 100%;
  width: min(19rem, calc(100vw - 2rem));
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: var(--surface);
  box-shadow: 0 8px 30px #0002;
  z-index: 40;
}

/* Keep landing navigation and account actions available while reading. */
.landing-shell > .site-header { position: sticky; top: 0; background: var(--surface); }
.landing-shell #courses { scroll-margin-top: 9rem; }
.landing-shell .site-header:not(.learning-header) .desktop-nav { display: flex !important; }
.landing-shell .desktop-nav > a { white-space: nowrap; }
.landing-shell .header-signup { border: 1px solid var(--line); border-radius: .5rem; padding: .5rem .75rem; color: var(--accent-deep); }
@media (max-width: 800px) {
  .landing-shell > .site-header { gap: .5rem; padding-inline: 1rem; }
  .landing-shell .desktop-nav { width: 100%; justify-content: flex-end; gap: 1rem; }
  .landing-shell .desktop-nav > a:is([href="/blog"], [href="/challenges"]) { display: none; }
}
.landing-faq-item summary { list-style: none; min-height: 3.5rem; }
.landing-faq-item summary::-webkit-details-marker { display: none; }
.landing-faq-item summary:focus-visible { outline: 2px solid var(--accent-deep); outline-offset: 3px; }
.landing-faq-toggle { flex: none; font-size: 1.5rem; line-height: 1; }
.landing-faq-item[open] .landing-faq-toggle { transform: rotate(45deg); }

/* Homepage presentation stays scoped so lesson and authoring surfaces keep their scale. */
.landing-shell {
  --surface: #fffefa;
  --fog: #f5f6f8;
  --ink: #202d3b;
  --ink-muted: #536171;
  --line: #dce2e8;
  --accent-deep: #285f91;
  --link: #285f91;
  background: var(--surface);
}
.landing-shell > .site-header {
  min-height: 80px;
  padding-inline: max(1.5rem, calc((100% - 1120px) / 2));
  gap: 2rem;
  background: color-mix(in srgb, var(--surface) 96%, transparent);
}
.landing-shell .site-header .brand {
  order: 0;
  font-size: 1.15rem;
}
.landing-shell .site-header .explore-menu {
  order: 1;
}
.landing-shell .site-header .desktop-nav {
  order: 2;
  gap: 1.5rem;
}

.landing-shell .header-signup {
  background: var(--accent-deep);
  color: white;
  border-color: var(--accent-deep);
}
.landing-page {
  overflow: clip;
}
.landing-page h1,
.landing-page h2,
.landing-page h3 {
  text-wrap: balance;
}
.landing-page .landing-hero {
  max-width: 1120px;
  padding-block: 5rem 4rem;
}
.landing-hero > div {
  gap: 3rem;
}
.landing-hero h1 {
  font-size: clamp(2.25rem, 3.8vw, 3.5rem);
  line-height: 1.4;
  letter-spacing: -0.025em;
}
.landing-hero p {
  text-wrap: pretty;
}
.landing-hero figure {
  background: #f1f5f8;
  border-color: #cdd9e3;
  box-shadow: 0 16px 48px #203b5510;
  transform: rotate(-1deg);
}
html[dir="ltr"] .landing-hero figure {
  transform: rotate(1deg);
}
.landing-hero figcaption {
  font-size: 0.8rem;
}
.landing-hero figure > div:last-child {
  padding-block: 1rem;
}
.landing-secondary-link {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--accent-deep);
  font-weight: 600;
  min-height: 48px;
}
.landing-secondary-link:hover {
  text-decoration: underline;
  text-underline-offset: 5px;
}
.landing-page .learning-path {
  background: #f1f5f8;
  border-block: 1px solid var(--line);
}
.landing-page .learning-path > div {
  padding-block: 3.5rem;
}
.landing-page .path-eyebrow {
  letter-spacing: 0;
}
.landing-page .learning-path ul.list-disc {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 2rem;
  max-width: none;
  padding: 0;
  margin-block: 1.25rem;
  list-style: none;
  font-size: 0.95rem;
}
.landing-page .path-legend {
  margin-top: 1.5rem;
}
.landing-page .path-tree {
  margin-top: 1.5rem;
}
.landing-page .path-nodes {
  grid-template-rows: repeat(4, 160px);
}
.landing-page .path-connectors {
  height: 784px;
}
.landing-page .path-card {
  padding: 1rem;
  border-color: #cdd7e0;
  border-top-color: var(--path-color);
  background: var(--surface);
  box-shadow: 0 3px 8px #203b5506;
}
.landing-page .path-card h3 {
  font-size: 1rem;
}
.landing-page .path-level,
.landing-page .path-requires,
.landing-page .path-status {
  font-size: 0.75rem;
}
.landing-page .path-card.course-coming-soon {
  opacity: 1;
  background: #f5f7f9;
  border-top-color: color-mix(in srgb, var(--path-color) 45%, var(--line));
  box-shadow: none;
}
.landing-page .course-coming-soon h3,
.landing-page .course-coming-soon .path-code {
  color: var(--ink-muted);
}
.landing-page .course-coming-soon .path-status {
  color: var(--ink-muted);
  font-weight: 400;
}
.landing-python {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  align-items: center;
  gap: 3rem;
  padding-block: 4rem;
}
.landing-python > div:last-child {
  background: white;
  box-shadow: 0 8px 24px #203b5508;
}
.landing-preview-actions a,
.landing-data-actions a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
}
.landing-preview-actions > a:first-child {
  padding-inline: 1.25rem;
}
.landing-preview-copy h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
}
.landing-data {
  background: #f6f3fa;
}
.landing-data > div {
  padding-block: 3.5rem;
}
.landing-data-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 1.5rem 3rem;
  align-items: center;
}
.landing-data-visual {
  min-width: 0;
  grid-column: 2;
  grid-row: 1 / span 2;
}
.landing-data-visual figure {
  border: 0;
  border-radius: 1rem;
  box-shadow: none;
}
.landing-diagram-scroll {
  max-width: 100%;
  overflow-x: auto;
  direction: ltr;
  border-radius: 0.5rem;
}
.landing-diagram-scroll:focus-visible {
  outline: 2px solid var(--accent-deep);
  outline-offset: 4px;
}
.landing-diagram-hint {
  display: none;
}
.landing-data-actions {
  align-self: start;
}
.landing-data h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
}
.landing-page [aria-labelledby="instructor-heading"] {
  padding-block: 3.5rem;
}
.landing-page [aria-labelledby="instructor-heading"] > div {
  gap: 2rem;
}
.landing-page [aria-labelledby="sources-heading"] {
  background: transparent;
}
.landing-page [aria-labelledby="sources-heading"] > div {
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: 3rem;
  padding-block: 3.5rem;
}
.landing-page [aria-labelledby="sources-heading"] h2 {
  font-size: 1.75rem;
}
.landing-page [aria-labelledby="sources-heading"] > div > p:first-of-type {
  grid-column: 1;
  margin-top: 1rem;
}
.landing-page [aria-labelledby="sources-heading"] > div > div {
  grid-column: 2;
  grid-row: 1 / span 2;
  margin: 0;
  padding-inline-start: 2rem;
  border-inline-start: 1px solid var(--line);
}
.landing-source-label,
.landing-source-links {
  grid-column: 1 / -1;
}
.landing-source-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--ink-muted);
}
.landing-source-links {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 1rem 1.5rem;
  margin-top: 0.75rem;
}
.landing-source-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 64px;
  border-radius: 0.5rem;
}
.landing-source-links img {
  width: 100%;
  max-width: 112px;
  height: 32px;
  object-fit: contain;
}
/* Optical sizing accounts for the stacked marks and padding in their assets. */
.landing-source-links img[src$="/stanford.png"] {
  height: 64px;
}
.landing-source-links img[src$="/harvard.svg"] {
  height: 56px;
}
.landing-source-links img[src$="/deeplearning-ai.png"] {
  max-width: 160px;
  height: 48px;
}
.landing-source-links a:hover {
  background: var(--fog);
}
@media (max-width: 640px) {
  .landing-source-links {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.5rem 1rem;
  }
}
.landing-page [aria-labelledby="faq-heading"] {
  background: #f5f6f8;
}
.landing-faq-list {
  display: grid;
  gap: 0;
}
.landing-page .landing-faq-item {
  border-bottom: 1px solid var(--line);
  padding-block: 0.25rem;
}
.landing-page .landing-faq-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1rem;
  cursor: pointer;
  font-weight: 600;
}
.landing-page .landing-faq-item p {
  padding-block: 0 1.25rem;
  line-height: 2;
  color: var(--ink-muted);
  max-width: 48rem;
}
.landing-more-questions > summary {
  color: var(--link);
  cursor: pointer;
  padding-block: 0.5rem;
  text-underline-offset: 4px;
}
.landing-more-questions[open] > summary {
  font-weight: 600;
}
@media (hover: hover) {
  .landing-page a.path-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 24px #203b5512;
  }
}
@media (max-width: 900px) {
  .landing-shell > .site-header {
    gap: 1rem;
  }
  .landing-shell .site-header .desktop-nav {
    gap: 1rem;
  }
  .landing-shell .desktop-nav > a[href="/challenges"] {
    display: none;
  }
  .landing-hero > div {
    gap: 2rem;
  }
}
@media (max-width: 800px) {
  .landing-shell > .site-header {
    min-height: 68px;
    flex-wrap: wrap;
    padding: 0.75rem 1rem;
    gap: 0.5rem 1rem;
  }
  .landing-shell .site-header .brand {
    margin-inline-end: 0;
  }
  .landing-shell .site-header:not(.learning-header) .desktop-nav {
    width: auto;
    margin: 0;
  }
  .landing-shell .desktop-nav .primary-reference-link {
    display: none;
  }
  .landing-shell .site-header .explore-menu {
    order: 1;
  }
  .landing-shell .site-header .brand span {
    display: inline;
  }
  .landing-shell .header-signup {
    display: none;
  }
  .landing-page .landing-hero {
    padding-block: 3rem;
  }
  .landing-hero figure,
  html[dir="ltr"] .landing-hero figure {
    transform: none;
  }
  .landing-python {
    gap: 2rem;
  }
}
@media (max-width: 800px) {
  .landing-python,
  .landing-data-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 1.5rem;
  }
  .landing-python > div:last-child,
  .landing-data-visual {
    width: 100%;
    max-width: 40rem;
    justify-self: center;
  }
  .landing-data-visual {
    grid-column: auto;
    grid-row: auto;
  }
  .landing-data-actions {
    grid-row: 3;
  }
}

@media (max-width: 640px) {
  .landing-shell .site-header .brand {
    font-size: 1rem;
  }
  .landing-shell .site-header .desktop-nav {
    gap: 0.75rem;
  }
  .landing-shell .desktop-nav > a[href="/login"] {
    display: none;
  }
  .landing-shell .site-header .brand img {
    width: 28px;
    height: 30px;
  }
  .landing-shell .explore-menu > summary {
    font-size: 0.8rem;
  }
  .landing-hero h1 {
    font-size: clamp(2rem, 9.2vw, 2.25rem);
    line-height: 1.45;
  }
  .landing-hero > div {
    gap: 2.5rem;
  }
  .landing-page .learning-path > div,
  .landing-data > div {
    padding-block: 2.5rem;
  }
  .landing-page .learning-path ul.list-disc {
    display: grid;
    gap: 0.5rem;
  }
  .landing-python,
  .landing-data-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 1.5rem;
  }
  .landing-python {
    padding-block: 2.5rem;
  }
  .landing-data-visual {
    grid-column: auto;
    grid-row: auto;
  }
  .landing-data-actions {
    grid-row: 3;
  }
  .landing-page [aria-labelledby="sources-heading"] > div {
    display: block;
  }
  .landing-page [aria-labelledby="sources-heading"] > div > div {
    margin-top: 2rem;
    border: 0;
    padding: 0;
  }
  .landing-page .path-card {
    min-height: 136px;
  }
}
/* Compact mobile sections retain the same reading rhythm and useful touch areas. */
@media (max-width: 640px) {
  .landing-diagram-scroll img {
    min-width: 560px;
  }
  .landing-diagram-hint {
    display: block;
    margin-top: 0.5rem;
    font-size: 0.8rem;
  }
  .landing-page [aria-labelledby="instructor-heading"],
  .landing-page [aria-labelledby="sources-heading"] > div,
  .landing-page [aria-labelledby="faq-heading"] > div {
    padding-block: 2.5rem;
  }
  .landing-footer > div {
    padding-block: 2.5rem;
  }
  .landing-footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.5rem;
  }
  .landing-footer-grid > :first-child,
  .landing-footer-grid > :last-child {
    grid-column: 1 / -1;
  }
  .landing-footer-grid > :last-child ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1.5rem;
  }
  .landing-footer-grid ul li {
    margin: 0;
  }
  .landing-footer-grid li a {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
  }
  .landing-page .landing-preview-actions {
    padding-inline: 1rem;
    gap: 0.75rem;
  }
}
@media (max-width: 360px) {
  .landing-shell .site-header .brand span {
    display: none;
  }
  .landing-shell > .site-header {
    gap: 0.5rem;
  }
}
@media (prefers-reduced-motion: reduce) {
  .landing-page a.path-card {
    transition: none;
  }
  .landing-page a.path-card:hover {
    transform: none;
  }
}

/* Reference streams converge into the academy's teaching approach. */
.curriculum-flow {
  border-block: 1px solid var(--line);
  background: radial-gradient(ellipse at 50% 56%, #e6f2ed 0, transparent 58%), #f8faf9;
}
.curriculum-intro { max-width: 660px; margin-inline: auto; text-align: center; }
.curriculum-eyebrow { color: #367468; font-size: .85rem; font-weight: 600; }
.curriculum-intro h2 { margin-block: .65rem 1rem; font-size: clamp(1.6rem, 3vw, 2.15rem); font-weight: 650; }
.curriculum-intro > p:last-child { color: var(--ink-muted); line-height: 1.9; }
.curriculum-diagram { margin-top: 2.5rem; }
.curriculum-stage-label { text-align: center; color: var(--ink-muted); font-size: .85rem; }
.curriculum-flow .landing-source-links { gap: 1rem; margin-top: 1rem; padding: 0; list-style: none; }
.curriculum-flow .landing-source-links a { height: 84px; padding: .65rem; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; box-shadow: 0 3px 12px #183d3004; transition: border-color .2s, transform .2s; }
.curriculum-flow .landing-source-links a:hover { border-color: #5a9788; transform: translateY(-3px); }
.curriculum-streams { width: 100%; height: 110px; display: block; overflow: visible; }
.curriculum-streams path { stroke: #72aa9a; stroke-width: 1.5; vector-effect: non-scaling-stroke; }
.curriculum-core { position: relative; max-width: 620px; margin-inline: auto; padding: 1.75rem 2rem; text-align: center; border: 1px solid #85b3a5; border-radius: 24px; background: var(--surface); box-shadow: 0 12px 48px #285e4b0c; }
.curriculum-core > img { margin: 0 auto .6rem; }
.curriculum-core h3 { font-size: 1.3rem; font-weight: 650; line-height: 1.7; margin-top: .35rem; }
.curriculum-principles { display: flex; flex-wrap: wrap; justify-content: center; gap: .5rem; padding: 0; margin: 1.1rem 0; list-style: none; }
.curriculum-principles li { border-radius: 100px; padding: .35rem .85rem; background: #edf5f1; color: #315f52; font-size: .9rem; }
.curriculum-philosophy { display: inline-block; color: var(--link); font-weight: 600; font-size: .9rem; padding-block: .6rem; text-underline-offset: 5px; }
.curriculum-philosophy:hover { text-decoration: underline; }
.curriculum-flow a:focus-visible { outline: 2px solid var(--accent-deep); outline-offset: 4px; }
.curriculum-outlet { height: 65px; width: 2px; background: #72aa9a; margin-inline: auto; position: relative; }
.curriculum-outlet span { position: absolute; bottom: -5px; left: 50%; transform: translateX(-50%); color: #367468; background: #f0f6f3; font-size: 1.5rem; line-height: 1; }
@media (max-width: 640px) {
  .curriculum-flow .landing-source-links { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .65rem; }
  .curriculum-flow .landing-source-links a { height: 76px; padding: .5rem; }
  .curriculum-flow .landing-source-links img { max-height: 50px; }
  .curriculum-streams { height: 75px; }
  .curriculum-streams g:nth-child(2n) { display: none; }
  .curriculum-core { padding: 1.4rem 1rem; }
}
@media (max-width: 640px) {
  .curriculum-streams g:nth-child(1) path { d: path("M 167 0 C 167 70, 500 35, 500 120"); }
  .curriculum-streams g:nth-child(3) path { d: path("M 500 0 C 500 70, 500 35, 500 120"); }
  .curriculum-streams g:nth-child(5) path { d: path("M 833 0 C 833 70, 500 35, 500 120"); }
}

/* A shared cycle carries knowledge in, gathers it, then sends it onward. */
.curriculum-streams .curriculum-stream-pulse {
  stroke: #277e69;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 12 108;
  stroke-dashoffset: 12;
  opacity: 0;
  animation: curriculum-stream-in 6s linear infinite;
}
.curriculum-outlet::before {
  content: "";
  position: absolute;
  inset-inline-start: -1px;
  top: 0;
  width: 4px;
  height: 14px;
  border-radius: 4px;
  background: #277e69;
  opacity: 0;
  animation: curriculum-stream-out 6s linear infinite;
}
.curriculum-core {
  animation: curriculum-gather 6s ease-in-out infinite;
}
@keyframes curriculum-stream-in {
  0% { stroke-dashoffset: 12; opacity: 0; }
  8% { opacity: 1; }
  42% { opacity: 1; }
  48%, 100% { stroke-dashoffset: -100; opacity: 0; }
}
@keyframes curriculum-gather {
  0%, 35%, 80%, 100% { box-shadow: 0 12px 48px #285e4b0c; }
  50%, 58% { box-shadow: 0 0 0 5px #72aa9a18, 0 12px 48px #285e4b20; }
}
@keyframes curriculum-stream-out {
  0%, 58% { transform: translateY(0); opacity: 0; }
  63% { opacity: 1; }
  78% { transform: translateY(48px); opacity: 1; }
  83%, 100% { transform: translateY(51px); opacity: 0; }
}
@media (prefers-reduced-motion: reduce) {
  .curriculum-streams .curriculum-stream-pulse,
  .curriculum-outlet::before,
  .curriculum-core { animation: none; }
  .curriculum-flow .landing-source-links a { transition: none; }
  .curriculum-flow .landing-source-links a:hover { transform: none; }
}

/* The curriculum's output continues directly into the roadmap below. */
.curriculum-flow { border-block-end: 0; }
.curriculum-flow > div { padding-bottom: 0; }
.curriculum-flow + .learning-path { border-top: 0; }
.landing-page .curriculum-flow + .learning-path {
  background: #f8faf9;
  border-top: 0;
}
.landing-page .curriculum-flow + .learning-path > div {
  padding-top: 1.5rem;
}
.landing-page .learning-path > div > .path-eyebrow,
.landing-page .learning-path > div > h2,
.landing-page .learning-path > div > h2 + p {
  text-align: center;
  margin-inline: auto;
}
.landing-page .learning-path > div > ul.list-disc,
.landing-page .learning-path > div > .path-legend {
  justify-content: center;
  text-align: center;
}

/* Knowledge travels through prerequisite branches in three successive stages. */
.landing-page .path-connectors .path-flow {
  stroke: #277e69;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-dasharray: 16 116;
}
.path-flow path {
  stroke-dashoffset: 16;
  opacity: 0;
  animation: roadmap-knowledge-flow 6s linear infinite;
}
.path-flow .path-flow-second { animation-delay: 2s; }
.path-flow .path-flow-third { animation-delay: 4s; }
@keyframes roadmap-knowledge-flow {
  0% { stroke-dashoffset: 16; opacity: 0; }
  4%, 24% { opacity: 1; }
  30%, 100% { stroke-dashoffset: -100; opacity: 0; }
}
@media (max-width: 700px) {
  .landing-page .path-cs102::before,
  .landing-page .path-ds201::before {
    animation: roadmap-mobile-flow 6s ease-in-out infinite;
  }
  .landing-page .path-ds201::before { animation-delay: 2s; }
}
@keyframes roadmap-mobile-flow {
  0%, 30%, 100% { transform: translateY(0); color: var(--ink-muted); }
  8% { transform: translateY(-3px); color: #277e69; }
  24% { transform: translateY(3px); color: #277e69; }
}
@media (prefers-reduced-motion: reduce) {
  .path-flow path { animation: none; }
  .landing-page .path-cs102::before,
  .landing-page .path-ds201::before { animation: none; }
}


.certificate-landing-frame{display:block;border:0;width:100%;height:610px;background:transparent}@media(max-width:720px){.certificate-landing-frame{height:920px}}

.faculty-profile { display: grid; grid-template-columns: 160px minmax(0, 1fr); gap: 2rem; align-items: start; margin-block: 2rem; }
.faculty-identity { width: 160px; }
.faculty-portrait { display: block; width: 160px; height: 160px; object-fit: cover; border-radius: 50%; }
.faculty-profile h2 { margin-block-start: 0; }
.faculty-profile p { line-height: 2; }
@media (max-width: 640px) { .faculty-profile { grid-template-columns: 1fr; } }

.faculty-socials { display: flex; flex-wrap: wrap; justify-content: center; gap: .5rem; margin-block-start: 1rem; }
.faculty-socials a { display: inline-flex; align-items: center; justify-content: center; padding: .25rem; text-decoration: none; }
.faculty-socials a:hover { opacity: .7; }
.faculty-socials a:focus-visible { outline: 2px solid currentColor; outline-offset: 3px; }
.faculty-socials svg { width: 1.25rem; height: 1.25rem; flex-shrink: 0; }

/* Course specimens occupy the spare side of the roadmap cards. */
.landing-page .path-card-illustrated { position: relative; }
.landing-page .path-card-illustrated > :is(h3, .path-requires, .path-status) {
  padding-inline-end: 34%;
}
.path-art {
  position: absolute;
  inset-inline-end: .75rem;
  bottom: .75rem;
  width: 30%;
  height: 105px;
  object-fit: contain;
  pointer-events: none;
}
.path-chat {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: .35rem;
  font-size: .65rem;
  line-height: 1.5;
}
.path-chat-row { display: flex; align-items: center; gap: .2rem; }
.path-chat-row > span:last-child { padding: .3rem .35rem; border-radius: .5rem; }
.path-chat-bot { align-self: start; }
.path-chat-bot > span:last-child { background: #edf2f7; color: #263f53; }
.path-chat-user { align-self: end; flex-direction: row-reverse; }
.path-chat-user > span:last-child { background: #d8efe6; color: #224d40; }
@media (max-width: 700px) {
  .path-art { width: 30%; height: 100px; }
}

/* Separate browsing from focused search in the shared site navigation. */
.site-header .search-menu { order: 1; }
.search-menu > summary,
.explore-menu > summary {
  display: flex;
  align-items: center;
  gap: .5rem;
  min-height: 44px;
  cursor: pointer;
  white-space: nowrap;
  list-style: none;
}
.search-menu > summary::-webkit-details-marker,
.explore-menu > summary::-webkit-details-marker { display: none; }
.search-menu > summary {
  border: 1px solid var(--line);
  border-radius: .35rem;
  min-width: 9rem;
  padding: .4rem .8rem;
  color: var(--accent-deep, var(--link));
}
.disclosure-caret { transition: transform .15s; }
.explore-menu[open] .disclosure-caret { transform: rotate(180deg); }
.explore-browser { width: min(52rem, calc(100vw - 3rem)); padding: .75rem; }
.explore-browser-grid { display: grid; grid-template-columns: 1fr 1fr; max-height: min(60vh, 36rem); }
#explore-categories { overflow-y: auto; padding-inline-end: .75rem; border-inline-end: 1px solid var(--line); }
.site-header #explore-categories button {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: .75rem;
  width: 100%;
  min-height: 48px;
  padding: .65rem .8rem;
  text-align: start;
  border: 2px solid transparent;
  border-radius: .5rem;
  color: var(--ink);
  font: inherit;
}
.site-header #explore-categories button[aria-selected="true"] {
  border-color: var(--accent-deep, var(--link));
  background: var(--link-soft, #edf2fa);
  color: var(--accent-deep, var(--link));
}
#explore-content { min-width: 0; overflow-y: auto; padding: .75rem 1rem; }
#explore-content h2 { font-size: .95rem; font-weight: 600; margin: 0 0 .75rem; }
#explore-content ul { margin: 0; max-height: none; }
#explore-content a { padding: .6rem .4rem; min-height: 44px; }
.explore-browser .explore-links { border-top: 1px solid var(--line); padding: .75rem .4rem 0; flex-wrap: wrap; }
.search-panel { width: min(38rem, calc(100vw - 3rem)); }
.search-field {
  display: flex !important;
  align-items: center;
  gap: .5rem;
  padding-inline: .75rem;
  border: 1px solid var(--ink-muted);
  border-radius: .35rem;
}
.search-field:focus-within { outline: 2px solid var(--accent-deep, var(--link)); outline-offset: 3px; }
.site-header .search-field .header-search {
  width: 100%;
  min-width: 0;
  margin: 0;
  padding: .6rem 0;
  border: 0;
  outline: 0;
  background: transparent;
  font-size: 1rem;
}
.search-field svg { flex: none; color: var(--ink-muted); }
#explore-status:empty, #search-status:empty { display: none; }
@media (max-width: 800px) {
  .search-menu > summary { min-width: 0; }
  .landing-shell .site-header .desktop-nav { margin-inline-start: auto; }
  .explore-browser, .search-panel { inset-inline: 1rem; width: calc(100vw - 2rem); }
}
@media (max-width: 480px) {
  .site-header:not(.learning-header) .brand span { display: none; }
  .explore-browser-grid { grid-template-columns: 1fr 1.1fr; }
  #explore-content { padding-inline: .65rem; }
  .site-header #explore-categories button { padding-inline: .4rem; font-size: .8rem; }
  #explore-content { font-size: .8rem; }
}

.path-avatar { width: 18px; height: 18px; display: inline-flex; align-items: center; justify-content: center; flex: none; border-radius: 50%; }
.path-avatar svg { width: 14px; height: 14px; }
.path-avatar-bot { background: #285f91; color: white; }
.path-avatar-user { background: #edf2f7; color: #536171; border: 1px solid #dce2e8; }

.course-introduction {
  display: flex;
  align-items: center;
  gap: 2rem;
  margin-block: 1rem 2rem;
  padding: 1.75rem 2rem;
  border: 1px solid var(--line);
  border-radius: .85rem;
  background: var(--surface);
  box-shadow: 0 4px 18px rgb(40 95 145 / 4%);
}
.course-introduction > div:first-child { flex: 1; min-width: 0; }
.course-introduction h1 { margin-block: 0; line-height: 1.5; }
.course-introduction .lead { margin-block: .75rem 0; }
.course-illustration { flex: 0 0 220px; display: flex; justify-content: center; }
.course-illustration .path-art { position: static; width: 100%; height: 200px; }
.course-illustration .path-chat { font-size: .95rem; gap: .65rem; }
.course-illustration .path-chat-row { gap: .5rem; }
.course-illustration .path-chat-row > span:last-child { padding: .5rem .65rem; }
.course-illustration .path-avatar { width: 28px; height: 28px; }
.course-illustration .path-avatar svg { width: 21px; height: 21px; }
@media (max-width: 640px) {
  .course-introduction { flex-direction: column; align-items: stretch; gap: 1rem; padding: 1.25rem; }
  .course-illustration { flex-basis: auto; align-self: center; width: 200px; }
  .course-illustration .path-art { height: 170px; }
}

/* Share the roadmap track palette with dashboard progress rings. */
.dashboard-card[data-track="cs"],
.landing-page [data-track="cs"] { --path-color: #285f91; }
.dashboard-card .course-progress-code {
  position: relative;
  width: 64px;
  min-width: 64px;
  height: 64px;
  padding: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--path-color);
  flex: none;
}
.course-progress-code > svg { position: absolute; inset: 0; width: 100%; height: 100%; transform: rotate(-90deg); fill: none; stroke-width: 4; }
.course-ring-track { stroke: color-mix(in srgb, var(--path-color) 16%, var(--surface)); }
.course-ring-value { stroke: var(--path-color); }
.course-progress-accessible { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); }

/* Illustrated cards need a readable column before the desktop tree fits. */
@media (min-width: 701px) and (max-width: 1000px) {
  .landing-page .path-connectors { display: none; }
  .landing-page .path-nodes { display: flex; flex-direction: column; gap: 1rem; max-width: 36rem; margin-inline: auto; }
  .landing-page .path-card { min-height: 160px; height: auto; }
  .landing-page .path-cs102::before,
  .landing-page .path-ds201::before { content: "↓"; display: block; text-align: center; color: var(--ink-muted); margin-bottom: 1rem; }
}
@media (max-width: 380px) {
  .landing-page .path-cs102 .path-card > :is(h3, .path-requires, .path-status) { padding-inline-end: 40%; }
  .landing-page .path-chat { width: 36%; font-size: .55rem; gap: .3rem; }
  .landing-page .path-chat-row > span:last-child { padding: .25rem .2rem; white-space: nowrap; }
  .landing-page .path-chat .path-avatar { width: 15px; height: 15px; }
  .landing-page .path-chat .path-avatar svg { width: 11px; height: 11px; }
}
@media (max-width: 800px) {
  .explore-browser-grid { height: min(55dvh, 32rem); grid-template-rows: minmax(0, 1fr); }
  #explore-categories, #explore-content { min-height: 0; }
}

.course-program-links {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  margin-block: -0.5rem 2rem;
}
.course-program-links a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.35rem;
  background: var(--surface);
  color: var(--link);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 600;
  line-height: 1.6;
}
.course-program-links a:hover { background: var(--fog); }
.course-program-links a:focus-visible { outline: 2px solid var(--link); outline-offset: 3px; }
.course-program-links svg { width: 1.4rem; height: 1.4rem; flex-shrink: 0; color: var(--ink); }
@media (max-width: 600px) {
  .course-program-links { grid-template-columns: 1fr; }
}

/* Global destinations and utilities remain distinct in every area. */
.site-header.platform-header {
  direction: ltr;
  box-sizing: border-box;
  gap: .75rem 1.25rem;
  padding: .75rem clamp(1rem, 3vw, 3rem);
}
.platform-header > .brand { order: 0; }
.platform-header .platform-primary { order: 1; direction: rtl; gap: .35rem; }
.platform-header .platform-primary a,
.platform-header .mobile-nav nav a { padding: .4rem .65rem; border-radius: .5rem; white-space: nowrap; text-decoration: none; }
.platform-header a[aria-current] { color: var(--ink); background: var(--fog); font-weight: 700; box-shadow: inset 0 -2px var(--link); }
.platform-header .context-destination { border: 1px solid var(--line); }
.platform-header .platform-utilities { order: 2; direction: rtl; margin-left: auto; display: flex; align-items: center; gap: 1rem; }
.platform-header .platform-utilities summary { white-space: nowrap; }
.platform-header .profile-panel { direction: rtl; }
.platform-header .mobile-nav { order: 1; direction: rtl; }
.platform-header .search-menu { order: initial; }
.platform-header .search-panel { direction: rtl; }
@media (max-width: 1200px) {
 .platform-header .brand span { display: none !important; }
 .platform-header .platform-primary { gap: .1rem; }
 .platform-header .platform-utilities { gap: .6rem; }
}
@media (max-width: 900px) {
 .site-header.platform-header .platform-primary { display: none; }
 .site-header.platform-header .mobile-nav { display: block; }
 .platform-header .mobile-nav > nav { direction: rtl; align-items: stretch; }
 .platform-header .development-menu { display: none; }
 .platform-header .platform-utilities { gap: .6rem; font-size: .8rem; }
 .platform-header .header-signup { display: none; }
 .platform-header .learning-context { font-size: .8rem; }
}
@media (max-width: 480px) {
 .site-header.platform-header { column-gap: .75rem; }
 .platform-header .search-menu summary > span { display: none; }
}

.platform-header .platform-local { display: flex; align-items: center; gap: .75rem; width: 100%; min-width: 0; order: 3; }
html[lang="en"] .platform-header :is(.platform-primary, .platform-utilities, .learning-context, .profile-panel, .search-panel) { direction: ltr; }

@media (max-width: 900px) {
 .platform-header .mobile-nav nav { position: absolute; top: 100%; left: 1rem; right: auto; min-width: 12rem; max-width: calc(100vw - 2rem); padding: 1rem; flex-direction: column; background: var(--surface); border: 1px solid var(--line); border-radius: .5rem; box-shadow: 0 8px 30px #0002; }
}
/* Keep the React host stretched inside the shared main-content landmark. */
.platform-header ~ main:has(> #playground-body) {
  display: flex;
  flex: 1;
  flex-direction: column;
  min-height: 0;
  min-width: 0;
}
.platform-header .platform-utilities > :is(a, button),
.platform-header .platform-utilities > details > summary {
  min-height: 2.75rem;
  display: inline-flex;
  align-items: center;
}

/* Each utility panel belongs to the control that opens it. */
.platform-header :is(.profile-menu, .search-menu, .mobile-nav) { position: relative; }
.platform-header .profile-menu > summary { border-radius: .4rem; gap: .4rem; }
.platform-header .profile-menu > summary::after { content: "⌄"; font-size: .8em; }
.platform-header :is(.profile-panel, .search-panel) {
  top: calc(100% + .5rem);
  right: 0;
  left: auto;
  inset-inline-end: auto;
  max-width: calc(100vw - 2rem);
  z-index: 50;
}
.platform-header .search-panel { width: min(32rem, calc(100vw - 2rem)); }
.platform-header .mobile-nav > nav { top: calc(100% + .5rem); left: 0; right: auto; z-index: 50; }

.community-moderation article { border: 1px solid var(--line); border-radius: 12px; padding: 1rem; margin-block: 1rem; }
.community-moderation pre { overflow: auto; max-block-size: 24rem; padding: 1rem; background: var(--surface); }
.community-moderation form { display: flex; flex-wrap: wrap; gap: .75rem; margin-block-start: 1rem; }
.community-moderation label { display: grid; flex-basis: 100%; gap: .5rem; }
.community-moderation textarea { box-sizing: border-box; inline-size: 100%; min-block-size: 5rem; font: inherit; }
.community-moderation button { font: inherit; padding: .5rem 1rem; cursor: pointer; }

.community-moderation select { font: inherit; max-inline-size: 100%; padding: .5rem; }
.community-moderation h2 { margin-block-start: 2rem; }
.community-moderation article a, .community-moderation p { overflow-wrap: anywhere; }

.community-moderation :is(button, select, textarea) { border: 1px solid var(--line); border-radius: .35rem; background: var(--surface); color: var(--ink); }
.community-moderation :is(button, select) { min-block-size: 2.75rem; }
.community-moderation textarea { padding: .75rem; }

/* Shared navigation icons follow the label direction in both languages. */
.platform-header :is(.platform-primary a, .mobile-nav nav a, .profile-panel a, .profile-panel button, .profile-menu > summary) {
  display: flex;
  align-items: center;
  gap: .5rem;
}
.platform-header .nav-icon {
  flex: 0 0 18px;
}

/* One primary navigation geometry on every page, including lesson workspaces. */
.site-header.platform-header {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: .5rem .75rem;
  padding: .5rem 1.5rem;
  min-height: 4.25rem;
}
.platform-header > .brand { grid-area: 1 / 1; }
.platform-header > .platform-primary,
.platform-header > .mobile-nav { grid-area: 1 / 2; }
.platform-header > .platform-utilities { grid-area: 1 / 3; }
.platform-header > .platform-local { grid-column: 1 / -1; }
.platform-header .brand span { display: none; }
@media (max-width: 760px) {
  .site-header.platform-header { padding-inline: .5rem; }
}

.course-accomplishment-link { display: inline-flex; align-items: center; gap: .4rem; }
.course-accomplishment-link .nav-icon { flex-shrink: 0; }

.course-certificate-ready { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem; margin-block: 1.5rem; padding: 1.25rem; border: 2px solid var(--accent-deep); border-radius: .6rem; background: var(--surface); }
.course-certificate-ready strong { font-size: 1.15rem; }
.course-certificate-ready p { margin: .3rem 0 0; color: var(--ink-muted); }
.course-certificate-ready .course-accomplishment-link { min-height: 44px; padding: .65rem 1.1rem; border-radius: .35rem; background: var(--accent-deep); color: #fff; font-weight: 700; text-decoration: none; }
.course-certificate-ready .course-accomplishment-link:hover { filter: brightness(.92); }
.course-certificate-ready .course-accomplishment-link:focus-visible { outline: 3px solid var(--link); outline-offset: 3px; }