@font-face {
  font-family: "Noto Sans SC";
  src: url("../fonts/NotoSansSC-Variable.woff2") format("woff2");
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
}

:root {
  --canvas: #ffffff;
  --surface: #f7f6f4;
  --surface-soft: #fbfbfa;
  --surface-lavender: #f0edf8;
  --surface-sky: #edf4fa;
  --ink: #1a1a1a;
  --charcoal: #37352f;
  --slate: #5d5b54;
  --muted: #787671;
  --hairline: #e5e3df;
  --hairline-strong: #c8c4be;
  --primary: #5645d4;
  --primary-hover: #4b3bc1;
  --primary-pressed: #4534b3;
  --primary-soft: #e6e0f5;
  --link: #315f9f;
  --success: #2f7d57;
  --warning: #9a681c;
  --error: #c73b4a;
  --font-ui: "Noto Sans SC", "Microsoft YaHei UI", "Microsoft YaHei", sans-serif;
  --font-code: "Cascadia Code", Consolas, monospace;

  /* Compatibility with the existing components. */
  --page: var(--canvas);
  --text: var(--ink);
  --text-secondary: var(--slate);
  --text-muted: var(--muted);
  --line: var(--hairline);
  --line-strong: var(--hairline-strong);
  --accent: var(--primary);
  --accent-hover: var(--primary-hover);
  --accent-soft: var(--primary-soft);
  --surface-subtle: var(--surface);
  --surface-violet: var(--surface-lavender);
  --font-sans: var(--font-ui);
  --font-mono: var(--font-code);
  --sans: var(--font-ui);
  --mono: var(--font-code);
  --serif: var(--font-ui);
  --mei-paper: var(--canvas);
  --mei-cream: var(--canvas);
  --mei-charcoal: var(--ink);
  --mei-orange: var(--primary);
  --mei-line: var(--hairline);
}

html {
  background: var(--canvas);
  scroll-behavior: smooth;
}

body.mei-workspace {
  min-height: 100dvh;
  margin: 0;
  background: var(--canvas);
  color: var(--charcoal);
  font-family: var(--font-ui);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.mei-workspace ::selection {
  background: var(--primary-soft);
  color: var(--ink);
}

.mei-workspace a,
.mei-workspace button,
.mei-workspace input,
.mei-workspace textarea {
  font-family: inherit;
}

.mei-workspace :focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
}

.mei-workspace .skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  padding: 9px 13px;
  border: 1px solid var(--hairline-strong);
  border-radius: 8px;
  background: var(--canvas);
  color: var(--ink);
  font-weight: 650;
  transform: translateY(-160%);
}

.mei-workspace .skip-link:focus {
  transform: translateY(0);
}

.mei-workspace .mei-wordmark,
.mei-workspace .mei-wordmark.dark {
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 17px;
  font-weight: 760;
  letter-spacing: -.035em;
  text-transform: none;
}

.mei-workspace .mei-topbar {
  position: sticky;
  top: 0;
  z-index: 30;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  min-height: 76px;
  padding: 0 max(32px, calc((100vw - 1320px) / 2));
  border-bottom: 0;
  background: rgba(255, 255, 255, .96);
  box-shadow: none;
  backdrop-filter: blur(16px);
}

.mei-workspace .mei-topbar nav {
  display: flex;
  align-items: center;
  gap: 30px;
}

.mei-workspace .mei-topbar nav a {
  position: relative;
  padding: 8px 0;
  border-radius: 0;
  color: var(--charcoal);
  font-size: 14px;
  font-weight: 620;
}

.mei-workspace .mei-topbar nav a:hover,
.mei-workspace .mei-topbar nav a.active {
  background: transparent;
  color: var(--ink);
}

.mei-workspace .mei-topbar nav a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 2px;
  left: 0;
  height: 2px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: right center;
  transition: transform .25s cubic-bezier(.22, 1, .36, 1);
}

.mei-workspace .mei-topbar nav a:hover::after,
.mei-workspace .mei-topbar nav a.active::after {
  transform: scaleX(1);
  transform-origin: left center;
}

.mei-workspace .top-user {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--slate);
  font-size: 13px;
}

.mei-workspace .top-user button {
  margin: 0;
  padding: 8px 14px;
  border: 1px solid var(--hairline);
  border-radius: 999px;
  background: var(--canvas);
  color: var(--charcoal);
  cursor: pointer;
}

.mei-workspace .top-user button:hover {
  border-color: var(--ink);
  background: var(--ink);
  color: #fff;
}

.mei-workspace .user-dot {
  display: none;
}

.mei-workspace .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 18px;
  border: 1px solid var(--hairline-strong);
  border-radius: 8px;
  background: var(--canvas);
  color: var(--ink);
  font-size: 14px;
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  box-shadow: none;
  cursor: pointer;
  transition: background-color .16s ease, border-color .16s ease, transform .16s ease;
}

.mei-workspace .btn:hover {
  transform: translateY(-1px);
  border-color: var(--hairline-strong);
  background: var(--surface);
}

.mei-workspace .btn:active {
  transform: scale(.98);
}

.mei-workspace .btn.primary {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

.mei-workspace .btn.primary:hover {
  border-color: var(--primary-hover);
  background: var(--primary-hover);
}

.mei-workspace .btn.primary:active {
  border-color: var(--primary-pressed);
  background: var(--primary-pressed);
}

.mei-workspace .btn:disabled {
  opacity: .55;
  cursor: wait;
}

/* Course workspace */
.workspace-home {
  width: min(100% - 64px, 1320px);
  margin: 0 auto;
  padding: 20px 0 56px;
}

.workspace-welcome {
  position: relative;
  min-height: 610px;
  overflow: hidden;
  border: 0;
  border-radius: 0;
  background: var(--canvas);
}

.welcome-copy {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 470px;
  width: min(54%, 680px);
  padding: 42px 0 70px;
}

.welcome-kicker {
  margin: 0 0 22px;
  color: var(--slate);
  font-size: 14px;
  font-weight: 600;
}

.welcome-copy h1 {
  max-width: 680px;
  margin: 0;
  color: var(--ink);
  font-size: clamp(54px, 5.8vw, 82px);
  font-weight: 760;
  line-height: .98;
  letter-spacing: -.055em;
  text-wrap: balance;
}

.welcome-copy h1 span {
  display: block;
}

.welcome-copy h1 #next-code {
  margin-bottom: 12px;
  color: var(--primary);
  font-size: .25em;
  font-weight: 650;
  letter-spacing: -.02em;
  line-height: 1;
}

.welcome-copy > p:not(.welcome-kicker) {
  max-width: 540px;
  margin: 24px 0 0;
  color: var(--slate);
  font-size: 18px;
  line-height: 1.7;
  text-wrap: pretty;
}

.welcome-copy .hero-actions {
  display: flex;
  align-items: center;
  gap: 24px;
  margin: 34px 0 0;
}

.welcome-copy .btn.primary {
  min-height: 52px;
  padding: 13px 24px;
  border-color: var(--ink);
  border-radius: 999px;
  background: var(--ink);
  font-size: 15px;
}

.welcome-copy .btn.primary:hover {
  border-color: #35343a;
  background: #35343a;
  box-shadow: none;
}

.course-text-link {
  color: var(--ink);
  font-size: 14px;
  font-weight: 650;
  text-decoration: underline;
  text-decoration-color: #c8c5c0;
  text-underline-offset: 5px;
  transition: text-decoration-color .2s ease;
}

.course-text-link:hover {
  color: var(--ink);
  text-decoration-color: var(--ink);
}

.welcome-progress {
  position: absolute;
  bottom: 18px;
  left: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px 20px;
  width: min(54%, 680px);
  padding-top: 18px;
  border-top: 1px solid var(--hairline);
}

.progress-meta {
  grid-column: 1 / -1;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

.progress-meta span,
.welcome-progress p {
  color: var(--muted);
  font-size: 12px;
}

.progress-meta strong {
  color: var(--ink);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

.welcome-progress p {
  margin: 0;
}

.welcome-progress #continue-note {
  text-align: right;
}

.welcome-progress .progress-line {
  grid-column: 1 / -1;
  width: 100%;
  height: 2px;
  overflow: hidden;
  background: #eceae7;
}

.welcome-progress .progress-line i {
  display: block;
  width: 0;
  height: 100%;
  background: var(--primary);
  transition: width .45s cubic-bezier(.22, 1, .36, 1);
}

.welcome-motion {
  position: absolute;
  top: 32px;
  right: 0;
  width: 42%;
  height: 500px;
  overflow: hidden;
  border-radius: 28px;
  background: #eeecf9;
  isolation: isolate;
}

.welcome-motion::before {
  content: "";
  position: absolute;
  inset: 13% -15% auto auto;
  width: 78%;
  aspect-ratio: 1;
  border: 1px solid rgba(86, 69, 212, .18);
  border-radius: 50%;
}

.motion-word {
  position: absolute;
  display: grid;
  place-items: center;
  min-width: 190px;
  min-height: 112px;
  padding: 18px 28px;
  border-radius: 22px;
  font-size: clamp(34px, 4vw, 56px);
  font-weight: 760;
  letter-spacing: -.05em;
  box-shadow: 0 24px 54px rgba(50, 42, 94, .1);
  will-change: transform;
}

.motion-word-one {
  top: 54px;
  left: 28px;
  background: #fff;
  color: var(--ink);
  transform: rotate(-5deg);
  animation: motion-card-one 7s ease-in-out infinite alternate;
}

.motion-word-two {
  top: 190px;
  right: 30px;
  background: var(--ink);
  color: #fff;
  transform: rotate(4deg);
  animation: motion-card-two 8s .6s ease-in-out infinite alternate;
}

.motion-word-three {
  bottom: 36px;
  left: 54px;
  min-width: 230px;
  background: var(--primary);
  color: #fff;
  transform: rotate(-2deg);
  animation: motion-card-three 7.5s 1s ease-in-out infinite alternate;
}

.motion-cursor {
  position: absolute;
  top: 42%;
  left: 45%;
  width: 18px;
  height: 18px;
  border: 3px solid var(--ink);
  border-top: 0;
  border-left: 0;
  transform: rotate(45deg);
  animation: motion-cursor 5s cubic-bezier(.22, 1, .36, 1) infinite;
}

@keyframes motion-card-one {
  to { transform: translate3d(12px, 10px, 0) rotate(-2deg); }
}

@keyframes motion-card-two {
  to { transform: translate3d(-14px, -8px, 0) rotate(1deg); }
}

@keyframes motion-card-three {
  to { transform: translate3d(18px, -10px, 0) rotate(2deg); }
}

@keyframes motion-cursor {
  0%, 18% { transform: translate3d(-55px, -70px, 0) rotate(45deg); opacity: 0; }
  24%, 65% { opacity: 1; }
  70%, 100% { transform: translate3d(72px, 92px, 0) rotate(45deg); opacity: 0; }
}

.learning-route,
.workspace-section {
  padding: 92px 0 0;
}

.workspace-section-title {
  max-width: 760px;
  margin-bottom: 36px;
}

.workspace-section-title h2 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(34px, 4vw, 50px);
  font-weight: 740;
  line-height: 1.1;
  letter-spacing: -.04em;
  text-wrap: balance;
}

.workspace-section-title p {
  max-width: 620px;
  margin: 14px 0 0;
  color: var(--slate);
  font-size: 16px;
  text-wrap: pretty;
}

.route-track {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--hairline);
  list-style: none;
}

.route-track li {
  position: relative;
  min-height: 126px;
  padding: 24px 22px;
  border-right: 1px solid var(--hairline);
}

.route-track li:last-child {
  border-right: 0;
}

.route-track li::after {
  content: "→";
  position: absolute;
  top: 22px;
  right: 18px;
  color: #b7b3ad;
}

.route-track li:last-child::after {
  display: none;
}

.route-track span,
.route-track strong {
  display: block;
}

.route-track span {
  color: var(--muted);
  font-size: 12px;
}

.route-track strong {
  margin-top: 30px;
  color: var(--ink);
  font-size: 16px;
  font-weight: 650;
}

.mei-workspace .curriculum-section {
  border: 0;
}

.mei-workspace .curriculum-list {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--ink);
}

.mei-workspace .curriculum-module {
  display: block;
  margin: 0;
  overflow: visible;
  border: 0;
  border-bottom: 1px solid var(--hairline);
  border-radius: 0;
  background: var(--canvas);
}

.mei-workspace .module-index {
  position: relative;
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr) auto 24px;
  gap: 20px;
  align-items: center;
  min-height: 84px;
  padding: 22px 4px;
  border: 0;
  background: var(--canvas);
  list-style: none;
  cursor: pointer;
}

.mei-workspace .module-index::-webkit-details-marker {
  display: none;
}

.mei-workspace .curriculum-module[open] .module-index {
  border-bottom: 0;
  background: var(--canvas);
}

.module-title {
  color: var(--ink);
  font-size: 17px;
  font-weight: 700;
}

.module-sub {
  color: var(--slate);
  font-size: 14px;
}

.mei-workspace .module-index small {
  margin: 0;
  color: var(--muted);
  font-size: 12px;
}

.module-toggle {
  position: relative;
  width: 18px;
  height: 18px;
}

.module-toggle::before,
.module-toggle::after {
  content: "";
  position: absolute;
  top: 8px;
  left: 3px;
  width: 12px;
  height: 1.5px;
  border-radius: 2px;
  background: var(--muted);
}

.module-toggle::after {
  transform: rotate(90deg);
  transition: transform .16s ease;
}

.curriculum-module[open] .module-toggle::after {
  transform: rotate(0);
}

.mei-workspace .lesson-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  padding: 0 0 28px;
}

.mei-workspace .lesson-row {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr) auto 18px;
  gap: 12px;
  align-items: center;
  min-height: 88px;
  padding: 16px 18px;
  border: 0;
  border-radius: 14px;
  background: #f6f6f5;
  color: var(--charcoal);
  transition: background-color .2s ease, transform .2s ease;
}

.mei-workspace .lesson-row:hover {
  padding-left: 18px;
  background: #efedf8;
  color: var(--charcoal);
  transform: translateY(-2px);
}

.mei-workspace .lesson-code {
  color: var(--primary);
  font: 600 12px/1.4 var(--font-code);
}

.mei-workspace .lesson-name {
  min-width: 0;
  display: grid;
  gap: 2px;
}

.mei-workspace .lesson-name strong {
  overflow: hidden;
  color: var(--charcoal);
  font-size: 14px;
  font-weight: 600;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mei-workspace .lesson-name small {
  overflow: hidden;
  color: var(--muted);
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mei-workspace .lesson-status {
  color: var(--muted);
  font-size: 11px;
  white-space: nowrap;
}

.mei-workspace .lesson-arrow {
  display: block;
  color: var(--muted);
}

.mei-workspace .lesson-row.complete {
  background: #f1f7f3;
}

.mei-workspace .lesson-row.complete .lesson-status {
  color: var(--success);
}

.workspace-support {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  margin-top: 96px;
  padding: 38px 0;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--hairline);
}

.workspace-support h2 {
  margin: 0;
  color: var(--ink);
  font-size: 25px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -.03em;
}

.workspace-support p {
  margin: 6px 0 0;
  color: var(--slate);
}

.workspace-support .support-actions {
  display: flex;
  gap: 10px;
  margin: 0;
}

.workspace-support .support-actions a {
  min-width: 104px;
  padding: 10px 16px;
  border: 1px solid var(--hairline-strong);
  border-radius: 999px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 650;
  text-align: center;
}

.workspace-support .support-actions a:hover {
  border-color: var(--ink);
  background: var(--ink);
  color: #fff;
}

.mei-workspace .mei-footer {
  display: flex;
  justify-content: space-between;
  margin-top: 34px;
  padding: 18px 0 8px;
  border-top: 0;
  color: var(--muted);
  font-size: 12px;
}

/* Lesson workspace */
.lesson-menu-toggle {
  display: none;
}

.lesson-workspace {
  display: grid;
  grid-template-columns: 230px minmax(0, 760px) 190px;
  gap: 42px;
  width: min(100% - 48px, 1320px);
  margin: 0 auto;
  padding: 32px 0 80px;
}

.lesson-sidebar,
.reader-toc {
  position: sticky;
  top: 96px;
  align-self: start;
  max-height: calc(100dvh - 118px);
  overflow-y: auto;
  scrollbar-width: thin;
}

.lesson-sidebar {
  padding-right: 10px;
}

.sidebar-home {
  display: block;
  margin-bottom: 14px;
  padding: 8px 10px;
  border-radius: 7px;
  color: var(--slate);
  font-size: 13px;
  font-weight: 600;
}

.sidebar-home:hover {
  background: var(--surface);
  color: var(--ink);
}

.sidebar-module {
  margin: 2px 0;
}

.sidebar-module summary {
  padding: 8px 10px;
  border-radius: 7px;
  color: var(--slate);
  font-size: 13px;
  font-weight: 600;
  list-style: none;
  cursor: pointer;
}

.sidebar-module summary::-webkit-details-marker {
  display: none;
}

.sidebar-module[open] summary {
  color: var(--ink);
}

.sidebar-module > div {
  display: grid;
  gap: 2px;
  margin: 2px 0 8px;
}

.sidebar-module a {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 4px;
  padding: 7px 10px;
  border-radius: 7px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.45;
}

.sidebar-module a span {
  color: var(--primary);
  font-family: var(--font-code);
  font-size: 11px;
}

.sidebar-module a:hover,
.sidebar-module a.active {
  background: var(--surface-lavender);
  color: var(--ink);
}

.lesson-workspace .reader-body {
  min-width: 0;
  max-width: none;
  padding: 0;
}

.lesson-workspace .back-course {
  display: inline-flex;
  margin: 0 0 26px;
  color: var(--link);
  font-size: 13px;
  font-weight: 600;
}

.lesson-workspace .lesson-header {
  padding: 0 0 32px;
  border: 0;
  border-bottom: 1px solid var(--hairline);
}

.lesson-context {
  margin: 0 0 10px;
  color: var(--primary);
  font-size: 13px;
  font-weight: 650;
}

.lesson-workspace .lesson-header h1 {
  margin: 0;
  color: var(--ink);
  font-size: 42px;
  font-weight: 720;
  line-height: 1.18;
  letter-spacing: -.035em;
}

.lesson-workspace .lesson-header > p:not(.lesson-context) {
  max-width: 650px;
  margin: 14px 0 0;
  color: var(--slate);
  font-size: 17px;
  line-height: 1.75;
}

.lesson-workspace .lesson-source {
  display: block;
  margin-top: 18px;
  color: var(--muted);
  font-size: 12px;
}

.lesson-workspace .lesson-meta {
  display: grid;
  grid-template-columns: .75fr 1.35fr 1.2fr;
  margin: 24px 0 0;
  border-block: 1px solid var(--hairline);
}

.lesson-workspace .lesson-meta > div {
  padding: 18px 20px 18px 0;
}

.lesson-workspace .lesson-meta dt {
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 650;
}

.lesson-workspace .lesson-meta dd {
  margin: 0;
  color: var(--charcoal);
  font-size: 14px;
  line-height: 1.65;
}

.lesson-workspace .lesson-content {
  padding: 12px 0 0;
  overflow-wrap: anywhere;
}

.lesson-workspace .lesson-content > section {
  padding: 34px 0;
}

.lesson-workspace .lesson-content > section + section {
  border-top: 1px solid var(--hairline);
}

.lesson-workspace .lesson-content h2,
.lesson-workspace .lesson-tasks h2,
.lesson-workspace .lesson-feedback h2,
.lesson-workspace .project-submit h2 {
  margin: 0 0 14px;
  color: var(--ink);
  font-size: 27px;
  font-weight: 680;
  line-height: 1.3;
  letter-spacing: -.025em;
}

.lesson-workspace .lesson-content h3 {
  margin: 36px 0 12px;
  color: var(--charcoal);
  font-size: 20px;
  font-weight: 680;
  line-height: 1.45;
  letter-spacing: -.015em;
}

.lesson-workspace .lesson-content h4 {
  margin: 28px 0 10px;
  color: var(--charcoal);
  font-size: 17px;
  font-weight: 680;
  line-height: 1.5;
}

.lesson-workspace .lesson-content p,
.lesson-workspace .lesson-content li {
  color: var(--charcoal);
  font-size: 16px;
  line-height: 1.82;
}

.lesson-workspace .lesson-content p {
  margin: 0 0 14px;
}

.lesson-workspace .lesson-content ul,
.lesson-workspace .lesson-content ol {
  margin: 14px 0;
  padding-left: 1.6em;
}

.lesson-workspace .source-list-group {
  display: grid;
  gap: 8px;
  margin: 18px 0 24px;
  padding-left: 1.25em;
}

.lesson-workspace .source-list-group li::marker {
  color: var(--ink);
}

.lesson-workspace .source-step {
  display: grid;
  grid-template-columns: 68px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  margin: 22px 0 12px;
  padding-top: 14px;
  border-top: 1px solid var(--hairline);
}

.lesson-workspace .source-step strong {
  color: var(--primary);
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 680;
}

.lesson-workspace .source-step span {
  color: var(--ink);
  font-size: 17px;
  font-weight: 650;
  line-height: 1.55;
}

.lesson-workspace .source-explain {
  margin: 22px 0;
  padding: 2px 0 2px 16px;
  border-left: 2px solid var(--hairline-strong);
}

.lesson-workspace .source-explain > strong {
  display: block;
  margin-bottom: 5px;
  color: var(--muted);
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 680;
}

.lesson-workspace .source-explain > p {
  margin-bottom: 0;
}

.lesson-workspace .source-figure {
  margin: 26px 0 34px;
}

.lesson-workspace .lesson-content img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0;
  border: 1px solid var(--hairline);
  border-radius: 12px;
}

.lesson-workspace .lesson-content table {
  display: block;
  max-width: 100%;
  margin: 22px 0;
  overflow-x: auto;
  border-collapse: collapse;
}

.lesson-workspace .lesson-content th,
.lesson-workspace .lesson-content td {
  padding: 10px 12px;
  border: 1px solid var(--hairline);
  color: var(--charcoal);
  font-size: 14px;
  line-height: 1.6;
  text-align: left;
  vertical-align: top;
}

.lesson-workspace .lesson-note,
.lesson-workspace .callout {
  margin: 18px 0;
  padding: 18px 20px;
  border: 0;
  border-radius: 10px;
  background: var(--surface-sky);
}

.lesson-workspace .warn {
  margin: 18px 0;
  padding: 18px 20px;
  border: 0;
  border-radius: 10px;
  background: #fbf4df;
  color: var(--charcoal);
}

.lesson-workspace pre,
.info-page pre {
  overflow-x: auto;
  padding: 18px;
  border-radius: 10px;
  background: #202124;
  color: #f4f4f2;
  font: 13px/1.7 var(--font-code);
}

.lesson-workspace code {
  font-family: var(--font-code);
}

.lesson-workspace .source-code {
  margin: 18px 0;
  overflow: hidden;
  border: 1px solid var(--hairline);
  border-radius: 10px;
}

.lesson-workspace .source-code summary {
  padding: 13px 16px;
  background: var(--surface);
  cursor: pointer;
}

.lesson-workspace .source-code pre {
  max-height: 520px;
  margin: 0;
  border-radius: 0;
}

.lesson-workspace .lesson-tasks,
.lesson-workspace .lesson-feedback,
.lesson-workspace .project-submit {
  margin-top: 28px;
  padding: 26px;
  border: 1px solid #e1dced;
  border-radius: 12px;
  background: var(--surface-lavender);
}

.lesson-workspace .lesson-tasks {
  padding: 24px 26px;
  border: 0;
  border-left: 3px solid var(--primary);
  border-radius: 0;
}

.lesson-workspace .lesson-feedback {
  border-color: var(--hairline);
  background: var(--surface-soft);
}

.lesson-workspace .micro-label {
  margin: 0 0 6px;
  color: var(--primary);
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 650;
  letter-spacing: 0;
  text-transform: none;
}

.lesson-workspace .lesson-tasks > p:not(.micro-label),
.lesson-workspace .lesson-feedback > p:not(.micro-label) {
  color: var(--slate);
  font-size: 13px;
}

.lesson-workspace .task-list {
  display: grid;
  gap: 0;
  margin: 18px 0;
  border: 0;
}

.lesson-workspace .task-list label {
  display: grid;
  grid-template-columns: 20px 1fr;
  gap: 10px;
  align-items: center;
  padding: 11px 0;
  border: 0;
  border-top: 1px solid rgba(15, 15, 15, .1);
  border-radius: 0;
  background: transparent;
}

.lesson-workspace .task-list label.done {
  margin: 0;
  padding: 11px 0;
  background: transparent;
}

.lesson-workspace .task-list label.done span {
  color: var(--muted);
  text-decoration: line-through;
}

.lesson-workspace .task-list input {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
}

.lesson-workspace .feedback-types {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin: 20px 0 14px;
}

.lesson-workspace .feedback-types button {
  min-height: 38px;
  padding: 8px 12px;
  border: 1px solid var(--hairline-strong);
  border-radius: 8px;
  background: var(--canvas);
  color: var(--slate);
  cursor: pointer;
}

.lesson-workspace .feedback-types button:hover,
.lesson-workspace .feedback-types button.selected {
  border-color: var(--primary);
  background: var(--primary-soft);
  color: var(--primary-pressed);
}

.lesson-workspace .feedback-message-label {
  display: block;
  margin-bottom: 7px;
  color: var(--charcoal);
  font-size: 13px;
  font-weight: 650;
}

.lesson-workspace .form-hint {
  margin: -5px 0 18px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.65;
}

.lesson-workspace textarea,
.lesson-workspace input,
.mei-workspace .auth-form input,
.mei-workspace .onboarding-card input,
.mei-workspace .inline-form input,
.mei-workspace .admin-login input {
  width: 100%;
  border: 1px solid var(--hairline-strong);
  border-radius: 8px;
  background: var(--canvas);
  color: var(--ink);
  font-size: 15px;
  outline: none;
}

.lesson-workspace textarea,
.lesson-workspace input {
  padding: 11px 12px;
}

.lesson-workspace textarea {
  min-height: 100px;
  resize: vertical;
}

.lesson-workspace textarea:focus,
.lesson-workspace input:focus,
.mei-workspace .auth-form input:focus,
.mei-workspace .onboarding-card input:focus,
.mei-workspace .inline-form input:focus,
.mei-workspace .admin-login input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(86, 69, 212, .12);
}

.lesson-workspace .lesson-pager {
  display: flex;
  justify-content: space-between;
  padding: 36px 104px 104px 0;
}

.lesson-workspace .lesson-pager a {
  color: var(--link);
  font-weight: 600;
}

.lesson-workspace .reader-toc {
  padding: 8px 0 0;
  border: 0;
}

.lesson-workspace .reader-toc p {
  margin: 0 0 10px;
  color: var(--ink);
  font-size: 13px;
  font-weight: 650;
  text-transform: none;
  letter-spacing: 0;
}

.lesson-workspace .reader-toc a {
  display: block;
  padding: 6px 0;
  color: var(--muted);
  font-size: 12px;
}

.lesson-workspace .reader-toc a:hover {
  color: var(--primary);
}

/* Authentication */
.mei-workspace.mei-auth-page {
  background: var(--canvas);
}

.mei-workspace .mei-auth-shell {
  display: grid;
  grid-template-columns: minmax(500px, 1.05fr) minmax(460px, .95fr);
  min-height: 100dvh;
}

.mei-workspace .mei-auth-story {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 100dvh;
  padding: 42px 6vw;
  overflow: hidden;
  border-right: 1px solid #e1dced;
  background: #f1eefb;
  color: var(--ink);
  isolation: isolate;
}

.mei-workspace .mei-auth-story::before,
.mei-workspace .mei-auth-story::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.mei-workspace .mei-auth-story::before {
  z-index: -2;
  background: url("../img/auth-workflow.png") 48% center / cover no-repeat;
  animation: auth-background-drift 18s ease-in-out infinite alternate;
}

.mei-workspace .mei-auth-story::after {
  z-index: -1;
  background: linear-gradient(90deg, rgba(248, 246, 255, .96) 0%, rgba(245, 242, 253, .78) 38%, rgba(242, 239, 252, .18) 72%, rgba(241, 238, 251, .04) 100%);
}

@keyframes auth-background-drift {
  from { transform: scale(1.015) translate3d(0, 0, 0); }
  to { transform: scale(1.035) translate3d(-4px, 2px, 0); }
}

.auth-story-copy {
  max-width: 650px;
  margin-top: 7vh;
}

.mei-workspace .mei-auth-story h1 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(38px, 4.15vw, 58px);
  font-weight: 720;
  line-height: 1.14;
  letter-spacing: -.04em;
}

.mei-workspace .mei-auth-story h1 span {
  display: block;
  white-space: nowrap;
}

.mei-workspace .auth-subtitle {
  max-width: 520px;
  margin-top: 18px;
  color: var(--slate);
  font-size: 17px;
}

.auth-story-outline {
  width: min(100%, 650px);
  margin-top: 52px;
  padding-top: 30px;
  border-top: 1px solid rgba(86, 69, 212, .18);
}

.auth-story-outline > p {
  max-width: 520px;
  margin: 0;
  color: var(--charcoal);
  font-size: 26px;
  font-weight: 620;
  line-height: 1.45;
}

.mei-workspace .mei-auth-panel {
  display: grid;
  place-items: center;
  padding: 52px 7vw;
  background: var(--canvas);
}

.mei-workspace .auth-panel-inner {
  width: min(100%, 460px);
}

.mei-workspace .auth-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  margin-bottom: 42px;
  padding: 4px;
  border: 0;
  border-radius: 10px;
  background: var(--surface);
}

.mei-workspace .auth-tab {
  padding: 10px 12px;
  border: 0;
  border-radius: 7px;
  background: transparent;
  color: var(--muted);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}

.mei-workspace .auth-tab.active {
  border: 0;
  background: var(--canvas);
  color: var(--ink);
  box-shadow: 0 1px 2px rgba(15, 15, 15, .08);
}

.mei-workspace .auth-heading {
  margin-bottom: 28px;
}

.mei-workspace .auth-heading h2 {
  margin: 0;
  color: var(--ink);
  font-size: 32px;
  font-weight: 680;
  line-height: 1.25;
  letter-spacing: -.025em;
}

.mei-workspace .auth-heading p,
.mei-workspace .auth-help {
  margin-top: 8px;
  color: var(--slate);
  font-size: 13px;
}

.mei-workspace .auth-form label,
.mei-workspace .onboarding-card label,
.mei-workspace .project-submit label {
  display: grid;
  gap: 7px;
  margin: 0 0 18px;
  color: var(--charcoal);
  font-size: 13px;
  font-weight: 600;
}

.mei-workspace .auth-form input,
.mei-workspace .onboarding-card input {
  min-height: 44px;
  padding: 10px 12px;
}

.mei-workspace .auth-submit {
  width: 100%;
  margin-top: 6px;
}

.mei-workspace .auth-error {
  color: var(--error);
}

.mei-workspace .onboarding-card {
  width: min(560px, calc(100% - 36px));
  margin: 10vh auto;
  padding: 42px;
  border: 1px solid var(--hairline);
  border-radius: 16px;
  background: var(--canvas);
  box-shadow: 0 12px 32px rgba(15, 15, 15, .08);
}

.mei-workspace .onboarding-card h1 {
  margin: 38px 0 12px;
  color: var(--ink);
  font-size: 36px;
  font-weight: 680;
  line-height: 1.25;
  letter-spacing: -.03em;
}

/* Reference and help */
.mei-workspace .info-page {
  width: min(100% - 64px, 1180px);
  margin: 0 auto;
  padding: 96px 0 100px;
}

.mei-workspace .info-head {
  max-width: 880px;
  margin-bottom: 88px;
}

.mei-workspace .info-head h1 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(52px, 7vw, 82px);
  font-weight: 760;
  line-height: 1;
  letter-spacing: -.055em;
  text-wrap: balance;
}

.mei-workspace .info-head p {
  max-width: 660px;
  margin: 24px 0 0;
  color: var(--slate);
  font-size: 17px;
  line-height: 1.7;
  text-wrap: pretty;
}

.mei-workspace .faq-list {
  overflow: visible;
  border: 0;
  border-top: 1px solid var(--ink);
  border-radius: 0;
}

.mei-workspace .faq-item {
  border: 0;
  border-bottom: 1px solid var(--hairline);
  background: var(--canvas);
}

.mei-workspace .faq-item:last-child {
  border-bottom: 0;
}

.mei-workspace .faq-item summary {
  position: relative;
  display: block;
  padding: 28px 54px 28px 0;
  color: var(--ink);
  font-size: 20px;
  font-weight: 670;
  letter-spacing: -.02em;
  list-style: none;
}

.mei-workspace .faq-item summary::before {
  display: none;
}

.mei-workspace .faq-item summary::-webkit-details-marker {
  display: none;
}

.mei-workspace .faq-item summary::after {
  content: "+";
  position: absolute;
  top: 22px;
  right: 0;
  color: var(--ink);
  font-size: 28px;
  font-weight: 350;
  transition: transform .25s cubic-bezier(.22, 1, .36, 1);
}

.mei-workspace .faq-item[open] summary::after {
  transform: rotate(45deg);
}

.mei-workspace .faq-a {
  max-width: 760px;
  padding: 0 54px 30px 0;
  color: var(--slate);
  font-size: 15px;
  line-height: 1.8;
}

.mei-workspace .ref-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: 1px solid var(--ink);
}

.mei-workspace .ref-card {
  display: grid;
  grid-template-columns: minmax(220px, .7fr) minmax(0, 1.3fr);
  gap: 48px;
  padding: 42px 0 48px;
  border: 0;
  border-bottom: 1px solid var(--hairline);
  border-radius: 0;
  background: var(--canvas);
}

.mei-workspace .ref-card h3 {
  margin: 0;
  color: var(--ink);
  font-size: 23px;
  font-weight: 700;
  letter-spacing: -.025em;
}

.mei-workspace .ref-card > p,
.mei-workspace .ref-card > div {
  margin-top: 0;
}

.mei-workspace .ref-card table {
  margin: 0;
}

.mei-workspace .ref-flow {
  margin: 0;
  color: var(--ink);
  font-size: 20px;
  font-weight: 600;
  line-height: 1.65;
  letter-spacing: -.015em;
  text-wrap: pretty;
}

.mei-workspace .ref-card pre {
  margin: 0;
  border: 0;
  border-radius: 14px;
  background: #1d1c21;
  color: #f8f7fb;
}

/* Admin keeps a denser product layout. */
.mei-workspace.admin-page {
  background: var(--surface-soft);
}

.mei-workspace .admin-login,
.mei-workspace .admin-shell {
  color: var(--charcoal);
  font-family: var(--font-ui);
}

.mei-workspace .admin-login {
  width: min(100% - 36px, 640px);
  margin: 10vh auto;
  padding: 38px;
  border: 1px solid var(--hairline);
  border-radius: 16px;
  background: var(--canvas);
  box-shadow: 0 12px 32px rgba(15, 15, 15, .08);
}

.mei-workspace .admin-login h1,
.mei-workspace .admin-head h1,
.mei-workspace .admin-section-head h2 {
  color: var(--ink);
  font-family: var(--font-ui);
}

.mei-workspace .admin-shell {
  max-width: 1180px;
}

.mei-workspace .admin-head,
.mei-workspace .admin-tabs,
.mei-workspace .admin-table,
.mei-workspace .admin-row {
  border-color: var(--hairline);
}

.mei-workspace .admin-tabs {
  gap: 4px;
  padding: 4px;
  border: 0;
  border-radius: 10px;
  background: var(--surface);
}

.mei-workspace .admin-tabs button {
  border: 0;
  border-radius: 7px;
}

.mei-workspace .admin-tabs button.active {
  border: 0;
  background: var(--canvas);
  color: var(--ink);
  box-shadow: 0 1px 2px rgba(15, 15, 15, .08);
}

.mei-workspace .admin-card-list article {
  border-color: var(--hairline);
  border-radius: 12px;
  background: var(--canvas);
}

.mei-workspace .admin-row button,
.mei-workspace .shot-links a,
.mei-workspace .admin-card-list article > div a {
  color: var(--primary);
}

.mei-workspace .admin-row-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 12px;
  align-items: center;
}

.mei-workspace .admin-row button.danger-link {
  color: #b93852;
}

.mei-workspace .admin-row button.danger-link:hover {
  color: #8f243a;
}

/* AI assistant */
.mei-workspace .mei-panel {
  overflow: hidden;
  border: 1px solid var(--hairline);
  border-radius: 16px;
  background: var(--canvas);
  box-shadow: 0 12px 32px rgba(15, 15, 15, .12);
}

.mei-workspace .mei-head {
  border-color: #e1dced;
  background: var(--surface-lavender);
  color: var(--ink);
}

.mei-workspace .mei-title span {
  color: var(--muted);
}

.mei-workspace .mei-close {
  color: var(--ink);
}

.mei-workspace .mei-msg.ai {
  border-color: var(--hairline);
  background: var(--surface);
  color: var(--charcoal);
}

.mei-workspace .mei-msg.me {
  background: var(--primary);
  color: #fff;
}

.mei-workspace .mei-inputrow {
  border-color: var(--hairline);
  background: var(--canvas);
}

.mei-workspace .mei-send {
  border-radius: 8px;
  background: var(--primary);
}

.mei-workspace .mei-send:hover {
  background: var(--primary-hover);
}

/* Refined transitions and admin preview */
.admin-preview-notice {
  position: sticky;
  top: 76px;
  z-index: 24;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 14px;
  min-height: 38px;
  padding: 7px 20px;
  border-bottom: 1px solid #ddd7ef;
  background: rgba(246, 243, 252, .96);
  color: var(--slate);
  font-size: 12px;
  backdrop-filter: blur(12px);
  animation: mei-bar-in .32s ease both;
}

.admin-preview-notice strong,
.admin-preview-notice a {
  color: var(--primary);
  font-weight: 680;
}

.admin-preview-notice a {
  padding-left: 14px;
  border-left: 1px solid #d9d2eb;
}

.admin-preview .preview-disabled {
  border-color: #d8d2e8;
  background: linear-gradient(135deg, #fbfafc, #f4f1fa);
}

.admin-preview .task-list label {
  cursor: default;
}

.admin-preview .task-list input {
  opacity: .55;
}

.admin-preview .top-user [data-user-name] {
  display: none;
}

.admin-head-actions {
  display: flex;
  gap: 10px;
  align-items: center;
}

.mei-workspace .mei-topbar nav a,
.mei-workspace .top-user button,
.mei-workspace .module-index,
.mei-workspace .ref-card,
.mei-workspace .faq-item summary,
.mei-workspace .feedback-types button,
.mei-workspace .task-list label,
.mei-workspace .reader-toc a,
.mei-workspace .admin-tabs button,
.mei-workspace .admin-row {
  transition: color .2s ease, background-color .2s ease, border-color .2s ease, box-shadow .2s ease, transform .2s ease;
}

.mei-workspace .btn.primary:hover {
  box-shadow: 0 8px 20px rgba(86, 69, 212, .16);
}

.mei-workspace input:focus,
.mei-workspace textarea:focus {
  box-shadow: 0 0 0 3px rgba(86, 69, 212, .1);
}

.mei-workspace .curriculum-module[open] .lesson-list,
.mei-workspace .faq-item[open] .faq-a {
  animation: mei-content-in .28s cubic-bezier(.22, 1, .36, 1) both;
}

.mei-workspace .faq-item summary:hover {
  background: var(--surface-soft);
}

.mei-workspace .task-list label:hover {
  background: rgba(240, 237, 248, .46);
}

.mei-workspace .feedback-types button:hover {
  border-color: #a89edc;
  background: var(--surface-lavender);
}

.mei-workspace .feedback-types button.selected:hover {
  background: var(--primary-hover);
}

.mei-workspace .admin-content > * {
  animation: mei-content-in .28s cubic-bezier(.22, 1, .36, 1) both;
}

.mei-workspace .admin-row:not(.admin-label):hover {
  background: rgba(240, 237, 248, .42);
}

.mei-auth-story > .mei-wordmark {
  animation: mei-fade-down .55s .08s ease both;
}

.auth-story-copy h1 span {
  animation: mei-title-in .7s cubic-bezier(.22, 1, .36, 1) both;
}

.auth-story-copy h1 span:nth-child(1) { animation-delay: .12s; }
.auth-story-copy h1 span:nth-child(2) { animation-delay: .2s; }
.auth-story-copy h1 span:nth-child(3) { animation-delay: .28s; }

.mei-workspace .auth-subtitle {
  animation: mei-fade-up .55s .36s ease both;
}

.auth-story-outline {
  animation: mei-fade-up .58s .46s ease both;
}

.mei-workspace .auth-panel-inner {
  animation: mei-panel-in .65s .16s cubic-bezier(.22, 1, .36, 1) both;
}

.page-ready .workspace-welcome,
.page-ready .info-head,
.page-ready .lesson-sidebar,
.page-ready .reader-body,
.page-ready .reader-toc,
.page-ready .admin-head,
.page-ready .admin-tabs {
  animation: mei-fade-up .56s cubic-bezier(.22, 1, .36, 1) both;
}

.page-ready .learning-route,
.page-ready .faq-list,
.page-ready .ref-grid {
  animation: mei-fade-up .56s .08s cubic-bezier(.22, 1, .36, 1) both;
}

.page-ready .curriculum-section,
.page-ready .workspace-support {
  animation: mei-fade-up .56s .14s cubic-bezier(.22, 1, .36, 1) both;
}

.page-ready .reader-body {
  animation-delay: .06s;
}

.page-ready .reader-toc {
  animation-delay: .12s;
}

.lesson-workspace .reader-body {
  transition: opacity .16s ease, transform .16s ease;
}

.lesson-workspace.chapter-switching .reader-body {
  opacity: .42;
  transform: translateY(4px);
  pointer-events: none;
}

@media (prefers-reduced-motion: reduce) {
  .lesson-workspace .reader-body {
    transition: none;
  }
}

@media (max-width: 720px) {
  .lesson-workspace .lesson-meta {
    grid-template-columns: 1fr;
  }

  .lesson-workspace .lesson-meta > div {
    padding: 14px 0;
    border-bottom: 1px solid var(--hairline);
  }

  .lesson-workspace .lesson-meta > div:last-child {
    border-bottom: 0;
  }

  .lesson-workspace .lesson-pager {
    padding-right: 82px;
    padding-bottom: 92px;
  }
}

@media (hover: hover) {
  .mei-workspace .ref-card:hover {
    background: #faf9fc;
  }

  .mei-workspace .curriculum-module:hover {
    border-color: var(--hairline);
    box-shadow: none;
  }

  .mei-workspace .lesson-row:hover {
    transform: translateX(3px);
  }
}

@keyframes mei-title-in {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: none; }
}

@keyframes mei-panel-in {
  from { opacity: 0; transform: translateX(18px); }
  to { opacity: 1; transform: none; }
}

@keyframes mei-fade-up {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: none; }
}

@keyframes mei-fade-down {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: none; }
}

@keyframes mei-content-in {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

@keyframes mei-bar-in {
  from { opacity: 0; transform: translateY(-100%); }
  to { opacity: 1; transform: none; }
}

@media (prefers-reduced-motion: reduce) {
  .mei-workspace *,
  .mei-workspace *::before,
  .mei-workspace *::after {
    scroll-behavior: auto !important;
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }

}

@media (max-width: 1023px) {
  .welcome-copy {
    width: 52%;
  }

  .welcome-progress {
    width: 52%;
  }

  .welcome-motion {
    width: 44%;
  }

  .lesson-workspace {
    grid-template-columns: 210px minmax(0, 1fr);
    gap: 30px;
  }

  .lesson-workspace .reader-toc {
    display: none;
  }

  .mei-workspace .mei-auth-shell {
    grid-template-columns: 1fr;
  }

  .mei-workspace .mei-auth-panel {
    order: 1;
    min-height: 100dvh;
    padding: 52px 24px;
  }

  .mei-workspace .mei-auth-story {
    order: 2;
    min-height: auto;
    padding: 40px 24px;
  }

  .auth-story-copy {
    margin-top: 54px;
  }

  .auth-story-outline {
    margin-top: 64px;
  }
}

@media (max-width: 767px) {
  .admin-preview-notice {
    top: 102px;
    justify-content: flex-start;
    flex-wrap: wrap;
    gap: 4px 10px;
    padding: 8px 18px;
  }

  .admin-preview-notice a {
    margin-left: auto;
  }

  .admin-head-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .mei-workspace .mei-topbar {
    grid-template-columns: 1fr auto;
    min-height: 102px;
    padding: 12px 18px 10px;
  }

  .mei-workspace .mei-topbar nav {
    grid-column: 1 / -1;
    grid-row: 2;
    justify-self: start;
    display: flex;
    gap: 24px;
  }

  .mei-workspace .top-user [data-user-name] {
    display: none;
  }

  .workspace-home {
    width: min(100% - 36px, 1320px);
    padding-top: 8px;
  }

  .workspace-welcome {
    display: flex;
    min-height: 0;
    flex-direction: column;
  }

  .welcome-copy {
    order: 1;
    min-height: 0;
    width: 100%;
    padding: 44px 0 38px;
  }

  .welcome-copy h1 {
    font-size: clamp(48px, 14vw, 64px);
    line-height: 1;
  }

  .welcome-copy > p:not(.welcome-kicker) {
    margin-top: 20px;
    font-size: 16px;
  }

  .welcome-copy .hero-actions {
    align-items: center;
    flex-direction: row;
    margin-top: 28px;
  }

  .welcome-copy .hero-actions .btn {
    width: auto;
  }

  .welcome-progress {
    position: static;
    order: 3;
    grid-template-columns: 1fr auto;
    gap: 8px 16px;
    width: 100%;
    margin-top: 28px;
    padding: 18px 0 0;
  }

  .welcome-motion {
    position: relative;
    top: auto;
    right: auto;
    order: 2;
    width: 100%;
    height: 330px;
    border-radius: 22px;
  }

  .motion-word {
    min-width: 138px;
    min-height: 82px;
    padding: 12px 18px;
    border-radius: 16px;
    font-size: 36px;
  }

  .motion-word-one {
    top: 34px;
    left: 20px;
  }

  .motion-word-two {
    top: 126px;
    right: 20px;
  }

  .motion-word-three {
    bottom: 24px;
    left: 34px;
    min-width: 170px;
  }

  .learning-route,
  .workspace-section {
    padding-top: 54px;
  }

  .workspace-section-title h2 {
    font-size: 34px;
  }

  .route-track {
    grid-template-columns: 1fr;
  }

  .route-track li {
    display: grid;
    grid-template-columns: 74px minmax(0, 1fr);
    align-items: center;
    min-height: 70px;
    padding: 16px 4px;
    border-right: 0;
    border-bottom: 1px solid var(--hairline);
  }

  .route-track li:last-child {
    border-bottom: 0;
  }

  .route-track li::after {
    top: 21px;
    right: 4px;
    transform: rotate(90deg);
  }

  .route-track strong {
    margin-top: 0;
  }

  .mei-workspace .module-index {
    grid-template-columns: minmax(0, 1fr) auto 18px;
    gap: 5px 10px;
    min-height: 80px;
    padding: 16px 4px;
  }

  .module-title {
    grid-column: 1;
  }

  .module-sub {
    grid-column: 1 / -1;
    grid-row: 2;
  }

  .mei-workspace .module-index small {
    grid-column: 2;
    grid-row: 1;
  }

  .module-toggle {
    grid-column: 3;
    grid-row: 1;
  }

  .mei-workspace .lesson-list {
    grid-template-columns: 1fr;
    padding: 0 0 22px;
  }

  .mei-workspace .lesson-name small {
    display: none;
  }

  .workspace-support {
    align-items: flex-start;
    flex-direction: column;
    margin-top: 64px;
    padding: 28px 0;
  }

  .workspace-support h2 {
    font-size: 24px;
  }

  .workspace-support .support-actions {
    width: 100%;
  }

  .workspace-support .support-actions a {
    flex: 1;
  }

  .mei-workspace .mei-footer {
    display: grid;
    gap: 4px;
    margin-top: 54px;
  }

  .lesson-menu-toggle {
    position: fixed;
    right: 110px;
    bottom: 18px;
    z-index: 45;
    display: inline-flex;
    min-height: 42px;
    padding: 9px 14px;
    border: 1px solid var(--primary);
    border-radius: 8px;
    background: var(--primary);
    color: #fff;
    font: 600 13px var(--font-ui);
    box-shadow: 0 8px 20px rgba(15, 15, 15, .14);
  }

  .lesson-workspace {
    display: block;
    width: min(100% - 36px, 760px);
    padding: 24px 0 72px;
  }

  .lesson-sidebar {
    position: fixed;
    inset: 58px 0 0 auto;
    z-index: 40;
    width: min(86vw, 340px);
    max-height: none;
    padding: 20px 18px 80px;
    overflow-y: auto;
    border-left: 1px solid var(--hairline);
    background: var(--canvas);
    box-shadow: -12px 0 32px rgba(15, 15, 15, .1);
    transform: translateX(105%);
    transition: transform .2s ease;
  }

  .page-ready .lesson-sidebar {
    animation: none;
  }

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

  .lesson-workspace .reader-toc {
    display: none;
  }

  .lesson-workspace .lesson-header h1 {
    font-size: 34px;
  }

  .lesson-workspace .lesson-header > p:not(.lesson-context) {
    font-size: 16px;
  }

  .lesson-workspace .lesson-content h2,
  .lesson-workspace .lesson-tasks h2,
  .lesson-workspace .lesson-feedback h2,
  .lesson-workspace .project-submit h2 {
    font-size: 24px;
  }

  .lesson-workspace .lesson-content p,
  .lesson-workspace .lesson-content li {
    font-size: 16px;
    line-height: 1.78;
  }

  .lesson-workspace .lesson-tasks,
  .lesson-workspace .lesson-feedback,
  .lesson-workspace .project-submit {
    padding: 20px;
  }

  .mei-workspace .mei-auth-panel {
    min-height: 100dvh;
    padding: 34px 20px 50px;
  }

  .mei-workspace .auth-tabs {
    margin-bottom: 34px;
  }

  .mei-workspace .auth-heading h2 {
    font-size: 28px;
  }

  .mei-workspace .mei-auth-story h1 {
    font-size: 38px;
  }

  .auth-story-outline {
    margin-top: 48px;
  }

  .auth-story-outline > p {
    font-size: 21px;
  }

  .mei-workspace .mei-auth-story::before {
    background-position: 48% center;
    opacity: .76;
  }

  .mei-workspace .mei-auth-story::after {
    background: linear-gradient(180deg, rgba(248, 246, 255, .96) 0%, rgba(245, 242, 253, .82) 48%, rgba(242, 239, 252, .42) 100%);
  }

  .mei-workspace .onboarding-card {
    margin: 5vh auto;
    padding: 30px 22px;
  }

  .mei-workspace .info-page {
    width: min(100% - 36px, 1180px);
    padding: 56px 0 72px;
  }

  .mei-workspace .info-head h1 {
    font-size: clamp(46px, 14vw, 62px);
  }

  .mei-workspace .ref-grid {
    grid-template-columns: 1fr;
  }

  .mei-workspace .ref-card {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 32px 0 36px;
  }

  .mei-workspace .info-head {
    margin-bottom: 56px;
  }

  .mei-workspace .faq-item summary {
    padding: 24px 44px 24px 0;
    font-size: 18px;
  }

  .mei-workspace .faq-item summary::after {
    top: 18px;
  }

  .mei-workspace .faq-a {
    padding: 0 36px 26px 0;
  }

  .mei-workspace .admin-login {
    padding: 28px 22px;
  }
}

/* Jitter-inspired learning workspace
   The visual language is intentionally original: course scenes are built with CSS. */
.workspace-home {
  width: 100%;
  max-width: none;
  padding: 0 0 56px;
  overflow: hidden;
}

.course-hero {
  display: grid;
  place-items: center;
  min-height: min(760px, calc(100dvh - 76px));
  padding: 90px 32px 80px;
  text-align: center;
}

.course-hero-copy {
  width: min(100%, 1040px);
}

.section-eyebrow {
  margin: 0 0 18px;
  color: var(--primary);
  font-size: 13px;
  font-weight: 720;
  letter-spacing: .02em;
}

.course-hero .hero-code {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 650;
}

.course-hero h1 {
  max-width: 1040px;
  margin: 0 auto;
  color: var(--ink);
  font-size: clamp(72px, 8.4vw, 118px);
  font-weight: 820;
  line-height: .92;
  letter-spacing: -.065em;
  text-wrap: balance;
}

.course-hero .hero-brief {
  max-width: 600px;
  margin: 28px auto 0;
  color: var(--slate);
  font-size: 18px;
  line-height: 1.65;
  text-wrap: balance;
}

.course-hero .hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  margin-top: 34px;
}

.course-hero .btn.primary {
  min-height: 54px;
  padding: 14px 26px;
  border-color: var(--ink);
  border-radius: 999px;
  background: var(--ink);
  font-size: 15px;
}

.course-hero .btn.primary:hover {
  border-color: #343238;
  background: #343238;
}

.hero-progress {
  width: min(100%, 560px);
  margin: 54px auto 0;
}

.hero-progress .progress-line {
  width: 100%;
  height: 2px;
  overflow: hidden;
  background: var(--hairline);
}

.hero-progress .progress-line i {
  display: block;
  width: 0;
  height: 100%;
  background: var(--primary);
  transition: width .55s cubic-bezier(.22, 1, .36, 1);
}

.progress-copy {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  margin-top: 10px;
  color: var(--muted);
  font-size: 12px;
}

.progress-copy strong {
  color: var(--ink);
  font-weight: 700;
}

.course-hero .welcome-kicker,
.course-hero .hero-code,
.course-hero h1,
.course-hero .hero-brief,
.course-hero .hero-actions,
.course-hero .hero-progress {
  animation: hero-enter .8s both cubic-bezier(.22, 1, .36, 1);
}

.course-hero .hero-code { animation-delay: .05s; }
.course-hero h1 { animation-delay: .1s; }
.course-hero .hero-brief { animation-delay: .18s; }
.course-hero .hero-actions { animation-delay: .24s; }
.course-hero .hero-progress { animation-delay: .3s; }

@keyframes hero-enter {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

.learning-route,
.workspace-section,
.workspace-support,
.mei-footer {
  width: min(100% - 64px, 1320px);
  margin-right: auto;
  margin-left: auto;
}

.learning-route {
  padding-top: 128px;
}

.workspace-section-title {
  max-width: 940px;
  margin-bottom: 52px;
}

.workspace-section-title h2,
.workspace-support h2 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(46px, 5.4vw, 76px);
  font-weight: 800;
  line-height: .98;
  letter-spacing: -.055em;
  text-wrap: balance;
}

.workspace-section-title p:not(.section-eyebrow),
.workspace-support p:not(.section-eyebrow) {
  max-width: 660px;
  margin: 22px 0 0;
  color: var(--slate);
  font-size: 17px;
}

.route-track {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.route-track li {
  min-height: 190px;
  padding: 24px 22px;
}

.route-track li::after {
  content: "→";
}

.route-track span {
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.route-track strong {
  margin-top: 52px;
  font-size: 19px;
}

.route-track small {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
}

.curriculum-section {
  padding-top: 150px;
}

.workspace-support {
  margin-top: 150px;
  padding: 88px 0;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--hairline);
}

.workspace-support h2 {
  max-width: 800px;
}

.workspace-support .support-actions {
  align-self: end;
}

.workspace-support .support-actions a {
  min-width: 220px;
  border-radius: 999px;
}

.mei-footer {
  padding-right: 0;
  padding-left: 0;
}

.mei-workspace .info-kicker,
.mei-workspace .ref-card-index,
.mei-workspace .faq-index {
  color: var(--muted);
  font-size: 13px;
  font-weight: 620;
  font-variant-numeric: tabular-nums;
}

.mei-workspace .ref-card-head {
  align-self: start;
}

.mei-workspace .ref-card-head h3 {
  margin-top: 8px;
}

.mei-workspace .faq-item summary {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  align-items: baseline;
}

.mei-workspace .faq-a {
  padding-left: 46px;
}

.mei-workspace .info-support {
  margin-top: 76px;
  padding-top: 28px;
  border-top: 1px solid var(--ink);
}

.mei-workspace .info-support p:last-child {
  max-width: 680px;
  margin: 8px 0 0;
  color: var(--slate);
  font-size: 16px;
}

@media (max-width: 900px) {
  .course-hero {
    min-height: 660px;
    padding: 72px 24px 64px;
  }

  .course-hero h1 {
    font-size: clamp(58px, 12vw, 88px);
  }

  .learning-route,
  .workspace-section,
  .workspace-support,
  .mei-footer {
    width: min(100% - 40px, 1320px);
  }

  .route-track {
    grid-template-columns: 1fr;
  }

  .route-track li {
    min-height: 0;
    padding: 20px 0;
    border-right: 0;
    border-bottom: 1px solid var(--hairline);
  }

  .route-track li::after {
    right: 4px;
  }

  .route-track strong {
    margin-top: 12px;
  }
}

@media (max-width: 600px) {
  .course-hero {
    min-height: 610px;
    padding: 54px 20px 56px;
  }

  .course-hero h1 {
    font-size: clamp(48px, 15vw, 66px);
  }

  .course-hero .hero-brief {
    font-size: 16px;
  }

  .course-hero .hero-actions {
    flex-direction: column;
    gap: 16px;
  }

  .course-hero .btn.primary {
    width: 100%;
    max-width: 320px;
  }

  .progress-copy {
    flex-direction: column;
    gap: 4px;
  }

  .workspace-section-title h2,
  .workspace-support h2 {
    font-size: clamp(40px, 12vw, 56px);
  }

  .learning-route {
    padding-top: 88px;
  }

  .curriculum-section {
    padding-top: 110px;
  }

  .workspace-support {
    margin-top: 110px;
    padding: 64px 0;
  }

  .workspace-support .support-actions {
    display: grid;
    grid-template-columns: 1fr;
    align-self: stretch;
    width: 100%;
  }

  .workspace-support .support-actions a {
    min-width: 0;
    width: 100%;
    box-sizing: border-box;
  }

  .mei-workspace .faq-item summary {
    grid-template-columns: 34px minmax(0, 1fr);
  }

  .mei-workspace .faq-a {
    padding-left: 34px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .course-hero .welcome-kicker,
  .course-hero .hero-code,
  .course-hero h1,
  .course-hero .hero-brief,
  .course-hero .hero-actions,
  .course-hero .hero-progress {
    animation: none !important;
  }
}

/* Jitter refinement v2: centered reveal hero and a locally animated outcome strip. */
.mei-workspace .mei-topbar {
  min-height: 88px;
  padding-right: max(40px, calc((100vw - 1440px) / 2));
  padding-left: max(40px, calc((100vw - 1440px) / 2));
  border-bottom: 1px solid rgba(26, 26, 26, .08);
}

.mei-workspace .mei-wordmark,
.mei-workspace .mei-wordmark.dark {
  font-size: 20px;
  font-weight: 800;
}

.mei-workspace .mei-topbar nav {
  gap: 38px;
}

.mei-workspace .mei-topbar nav a {
  font-size: 16px;
  font-weight: 660;
}

.mei-workspace .top-user {
  gap: 14px;
  font-size: 14px;
}

.mei-workspace .top-user button {
  min-height: 40px;
  padding: 9px 17px;
  font-size: 13px;
  font-weight: 650;
}

.admin-preview-notice {
  top: 88px;
}

.admin-preview .mei-topbar .top-user button {
  border-color: var(--ink);
  background: var(--ink);
  color: #fff;
}

.course-hero {
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  width: 100%;
  min-height: min(800px, calc(100dvh - 88px));
  margin-left: 0;
  padding: 70px 40px 84px;
  box-sizing: border-box;
}

.course-hero-copy {
  width: min(100%, 1320px);
  margin-inline: auto;
}

.course-hero .hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-height: 38px;
  margin: 0 0 34px;
  padding: 8px 18px;
  border-radius: 999px;
  background: #f1f0f3;
  color: var(--ink);
  font-size: 13px;
  line-height: 1;
  animation: hero-pill-in .62s .08s both cubic-bezier(.22, 1, .36, 1);
}

.course-hero .hero-pill strong {
  font-weight: 720;
}

.course-hero .hero-pill span {
  color: var(--primary);
  font-weight: 720;
}

.course-hero h1 {
  max-width: 1280px;
  font-size: clamp(68px, 7.4vw, 108px);
  line-height: .92;
  letter-spacing: -.065em;
  animation: none;
}

.hero-reveal {
  display: block;
  overflow: hidden;
  padding: 0 .08em .1em;
  margin: 0 -.08em -.1em;
}

.hero-reveal > span {
  display: block;
  transform: translateY(112%);
  animation: hero-line-reveal .95s .14s both cubic-bezier(.16, 1, .3, 1);
}

.hero-reveal + .hero-reveal > span {
  animation-delay: .24s;
}

.hero-reveal + .hero-reveal {
  margin-top: .2em;
}

.course-hero .hero-brief {
  margin-top: 30px;
  animation: hero-detail-in .72s .42s both cubic-bezier(.22, 1, .36, 1);
}

.course-hero .hero-brief strong {
  color: var(--ink);
  font-weight: 740;
}

.hero-wave {
  display: inline-block;
  font-size: .62em;
  font-style: normal;
  vertical-align: .12em;
  transform-origin: 72% 76%;
  animation: hero-wave 1.2s 1.05s ease-in-out 2;
}

.course-hero .hero-actions {
  margin-top: 32px;
  animation: hero-detail-in .72s .51s both cubic-bezier(.22, 1, .36, 1);
}

.course-hero .btn.primary {
  min-width: 196px;
  min-height: 58px;
  border-color: #aa8cff;
  background: #aa8cff;
  color: var(--ink);
  font-size: 16px;
  font-weight: 720;
}

.course-hero .btn.primary:hover {
  border-color: #9876f5;
  background: #9876f5;
}

.course-hero .hero-progress {
  margin-top: 50px;
  animation: hero-detail-in .72s .6s both cubic-bezier(.22, 1, .36, 1);
}

@keyframes hero-pill-in {
  from { opacity: 0; transform: translateY(12px) scale(.96); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

@keyframes hero-line-reveal {
  from { transform: translateY(112%); }
  to { transform: translateY(0); }
}

@keyframes hero-detail-in {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes hero-wave {
  0%, 100% { transform: rotate(0); }
  25% { transform: rotate(14deg); }
  50% { transform: rotate(-8deg); }
  75% { transform: rotate(10deg); }
}

.outcome-strip {
  width: min(100% - 80px, 1320px);
  margin: 0 auto;
  padding: 56px 0 82px;
}

.outcome-caption {
  display: grid;
  grid-template-columns: minmax(40px, 1fr) auto minmax(40px, 1fr);
  align-items: center;
  gap: 26px;
  color: var(--charcoal);
  text-align: center;
}

.outcome-caption span {
  height: 1px;
  background: var(--hairline);
  transform: scaleX(0);
  animation: outcome-line-in .8s .85s both cubic-bezier(.22, 1, .36, 1);
}

.outcome-caption span:first-child {
  transform-origin: right;
}

.outcome-caption span:last-child {
  transform-origin: left;
}

.outcome-caption p {
  margin: 0;
  font-size: 14px;
  opacity: 0;
  animation: outcome-item-in .6s .78s both ease;
}

.outcome-caption strong {
  font-weight: 760;
}

.outcome-list {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  align-items: center;
  gap: 18px;
  margin-top: 40px;
}

.outcome-item {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  min-height: 58px;
  color: var(--ink);
  opacity: 0;
  transform: translateY(15px);
  animation: outcome-item-in .65s both cubic-bezier(.22, 1, .36, 1);
}

.outcome-item:nth-child(1) { animation-delay: .88s; }
.outcome-item:nth-child(2) { animation-delay: .94s; }
.outcome-item:nth-child(3) { animation-delay: 1s; }
.outcome-item:nth-child(4) { animation-delay: 1.06s; }
.outcome-item:nth-child(5) { animation-delay: 1.12s; }
.outcome-item:nth-child(6) { animation-delay: 1.18s; }

.outcome-item i {
  display: grid;
  min-width: 32px;
  height: 32px;
  place-items: center;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  font-size: 11px;
  font-style: normal;
  font-weight: 800;
  transform-origin: 50% 70%;
  animation: outcome-icon-motion 3.4s 1.65s ease-in-out infinite;
}

.outcome-item:nth-child(2) i { animation-delay: 1.9s; }
.outcome-item:nth-child(3) i { animation-delay: 2.15s; }
.outcome-item:nth-child(4) i { animation-delay: 2.4s; }
.outcome-item:nth-child(5) i { animation-delay: 2.65s; }
.outcome-item:nth-child(6) i { animation-delay: 2.9s; }

.outcome-item:hover i {
  border-color: var(--primary);
  color: var(--primary);
  animation-play-state: paused;
  transform: translateY(-4px) rotate(-3deg);
}

.outcome-item strong {
  font-size: 17px;
  font-weight: 760;
  letter-spacing: -.03em;
}

@keyframes outcome-line-in {
  to { transform: scaleX(1); }
}

@keyframes outcome-item-in {
  to { opacity: 1; transform: translateY(0); }
}

@keyframes outcome-icon-motion {
  0%, 100% { transform: translateY(0) rotate(0); }
  34% { transform: translateY(-5px) rotate(-4deg); }
  68% { transform: translateY(2px) rotate(3deg); }
}

.learning-route {
  padding-top: 110px;
}

.workspace-section-title h2,
.workspace-support h2 {
  font-size: clamp(52px, 5.8vw, 82px);
}

.workspace-section-title {
  margin-bottom: 46px;
}

@media (max-width: 900px) {
  .mei-workspace .mei-topbar {
    padding-right: 24px;
    padding-left: 24px;
  }

  .course-hero h1 {
    font-size: clamp(60px, 9.5vw, 88px);
  }

  .outcome-strip {
    width: min(100% - 48px, 1320px);
  }

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

@media (max-width: 600px) {
  .mei-workspace .mei-topbar {
    min-height: 82px;
    padding: 10px 18px;
  }

  .mei-workspace .mei-wordmark,
  .mei-workspace .mei-wordmark.dark {
    font-size: 15px;
  }

  .mei-workspace .mei-topbar nav {
    gap: 18px;
  }

  .mei-workspace .mei-topbar nav a {
    font-size: 13px;
  }

  .mei-workspace .top-user {
    font-size: 0;
  }

  .mei-workspace .top-user button {
    min-height: 36px;
    padding: 8px 12px;
    font-size: 12px;
  }

  .course-hero {
    min-height: 650px;
    padding: 62px 18px 64px;
  }

  .course-hero .hero-pill {
    margin-bottom: 28px;
    font-size: 12px;
  }

  .course-hero h1 {
    font-size: clamp(38px, 10.7vw, 48px);
    line-height: .96;
    letter-spacing: -.055em;
  }

  .course-hero .hero-actions {
    margin-top: 28px;
  }

  .course-hero .btn.primary {
    min-height: 54px;
  }

  .course-hero .hero-progress {
    margin-top: 42px;
  }

  .outcome-strip {
    width: calc(100% - 36px);
    padding: 40px 0 70px;
  }

  .outcome-caption {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .outcome-caption span {
    display: none;
  }

  .outcome-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px 14px;
    margin-top: 28px;
  }

  .outcome-item {
    justify-content: flex-start;
    min-height: 52px;
  }

  .outcome-item strong {
    font-size: 15px;
  }

  .learning-route {
    padding-top: 80px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .course-hero .hero-pill,
  .hero-reveal > span,
  .course-hero .hero-brief,
  .course-hero .hero-actions,
  .course-hero .hero-progress,
  .outcome-caption span,
  .outcome-caption p,
  .outcome-item,
  .outcome-item i,
  .hero-wave {
    animation: none !important;
    opacity: 1;
    transform: none;
  }
}