:root {
  --ink: #f7fbff;
  --muted: #aebfcd;
  --soft: #d8e7f1;
  --bg: #071523;
  --panel: #0d2134;
  --panel-2: #122b43;
  --line: rgba(168, 198, 219, 0.18);
  --blue: #19a8e8;
  --yellow: #ffca3a;
  --coral: #f15b61;
  --green: #41d38a;
  --shadow: 0 22px 70px rgba(0, 0, 0, 0.32);
  color-scheme: dark;
  font-family: Inter, Aptos, "Segoe UI", system-ui, -apple-system, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: radial-gradient(circle at 70% 12%, #133456 0, #071523 38%, #050d17 100%);
  color: var(--ink);
}

button,
input {
  font: inherit;
}

button {
  border: 0;
  cursor: pointer;
}

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 292px minmax(0, 1fr);
}

.side-rail {
  position: sticky;
  top: 0;
  height: 100vh;
  padding: 28px 24px;
  border-right: 1px solid var(--line);
  background: rgba(5, 13, 23, 0.82);
  backdrop-filter: blur(20px);
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  letter-spacing: 0;
}

.brand-mark {
  position: relative;
  width: 42px;
  height: 42px;
  display: inline-block;
}

.brand-mark span {
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--blue);
}

.brand-mark span:nth-child(1) { left: 12px; top: 0; background: var(--coral); }
.brand-mark span:nth-child(2) { left: 0; top: 12px; }
.brand-mark span:nth-child(3) { right: 0; top: 12px; background: var(--yellow); }
.brand-mark span:nth-child(4) { left: 12px; bottom: 0; background: var(--coral); }
.brand-mark span:nth-child(5) { left: 13px; top: 13px; width: 16px; height: 16px; background: #617890; border: 2px solid var(--yellow); }

.progress-ring {
  min-height: 118px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 20px;
  background: linear-gradient(160deg, rgba(25, 168, 232, 0.12), rgba(65, 211, 138, 0.08));
}

.progress-ring span {
  display: block;
  font-size: 42px;
  line-height: 1;
  font-weight: 800;
}

.progress-ring small {
  color: var(--muted);
}

.stage-nav {
  display: grid;
  gap: 8px;
  overflow: auto;
  padding-right: 4px;
}

.stage-tab {
  width: 100%;
  min-height: 48px;
  border-radius: 8px;
  padding: 10px 12px;
  color: var(--muted);
  background: transparent;
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 10px;
  align-items: center;
  text-align: left;
}

.stage-tab:hover,
.stage-tab:focus-visible {
  outline: 2px solid rgba(25, 168, 232, 0.45);
  outline-offset: 2px;
}

.stage-tab.is-active {
  color: var(--ink);
  background: rgba(25, 168, 232, 0.13);
}

.stage-tab.is-locked {
  opacity: 0.55;
  cursor: not-allowed;
}

.stage-number {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: rgba(255, 255, 255, 0.08);
  color: var(--soft);
  font-size: 13px;
  font-weight: 800;
}

.stage-tab.is-done .stage-number {
  background: var(--green);
  color: #032114;
}

.main-stage {
  min-width: 0;
  padding: 28px;
}

.stage-view {
  min-height: calc(100vh - 56px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: linear-gradient(180deg, rgba(13, 33, 52, 0.96), rgba(7, 21, 35, 0.96));
  box-shadow: var(--shadow);
  overflow: hidden;
}

.hero {
  min-height: calc(100vh - 56px);
  background-image: linear-gradient(90deg, rgba(5, 13, 23, 0.96) 0%, rgba(5, 13, 23, 0.72) 48%, rgba(5, 13, 23, 0.32) 100%), url("./assets/ai-learning-journey.png");
  background-size: cover;
  background-position: center;
  padding: 72px;
  display: grid;
  align-content: center;
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--blue);
  font-weight: 800;
  font-size: 14px;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 640px;
  font-size: 64px;
  line-height: 1.02;
  letter-spacing: 0;
  margin-bottom: 22px;
}

h2 {
  font-size: 40px;
  line-height: 1.12;
  letter-spacing: 0;
  margin-bottom: 12px;
}

h3 {
  font-size: 22px;
  margin-bottom: 10px;
}

.lead {
  max-width: 660px;
  font-size: 22px;
  line-height: 1.45;
  color: var(--soft);
}

.hero-actions,
.stage-actions,
.quiz-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 28px;
}

.course-hero {
  grid-template-columns: minmax(300px, 0.82fr) minmax(460px, 1.18fr);
  gap: 52px;
  align-items: center;
  align-content: center;
  background-image:
    linear-gradient(90deg, rgba(5, 13, 23, 0.97) 0%, rgba(5, 13, 23, 0.82) 52%, rgba(5, 13, 23, 0.54) 100%),
    url("./assets/ai-learning-journey.png");
}

.course-intro {
  align-self: center;
}

.course-intro h1 {
  max-width: 620px;
  font-size: 58px;
}

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

.course-card {
  min-width: 0;
  min-height: 430px;
  padding: 24px;
  border: 1px solid rgba(168, 198, 219, 0.26);
  border-top: 4px solid var(--yellow);
  border-radius: 8px;
  background: rgba(7, 21, 35, 0.9);
  box-shadow: 0 20px 54px rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(18px);
  display: grid;
  grid-template-rows: auto 1fr auto auto;
  gap: 20px;
}

.course-card-level2 {
  border-top-color: var(--green);
  background: rgba(10, 32, 40, 0.92);
}

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

.course-number {
  color: var(--yellow);
  font-size: 34px;
  line-height: 1;
  font-weight: 900;
}

.course-card-level2 .course-number,
.course-card-level2 .course-label {
  color: var(--green);
}

.course-type {
  padding: 6px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--soft);
  font-size: 12px;
  font-weight: 800;
}

.course-label {
  margin-bottom: 8px;
  color: var(--yellow);
  font-size: 13px;
  font-weight: 900;
  text-transform: uppercase;
}

.course-card h2 {
  font-size: 30px;
}

.course-card p:not(.course-label) {
  color: var(--soft);
  line-height: 1.5;
}

.course-meta {
  justify-content: flex-start;
  flex-wrap: wrap;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.course-meta span + span::before {
  content: "•";
  margin-right: 10px;
  color: var(--blue);
}

.course-card .button {
  width: 100%;
}

.course-card-level2 .button {
  color: #032114;
  border-color: transparent;
  background: var(--green);
}

.course-guidance {
  grid-column: 1 / -1;
  max-width: 900px;
  margin: -24px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.button {
  min-height: 46px;
  border-radius: 8px;
  padding: 0 18px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: #031525;
  background: var(--yellow);
  font-weight: 800;
}

.button.secondary {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.09);
  border: 1px solid var(--line);
}

.button:disabled {
  opacity: 0.48;
  cursor: not-allowed;
}

.lesson {
  padding: 30px 36px 18px;
  display: grid;
  grid-template-rows: auto 1fr auto;
  gap: 18px;
  min-height: calc(100vh - 56px);
  height: calc(100vh - 56px);
}

.lesson-header {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 1px solid var(--line);
  padding-bottom: 22px;
}

.lesson-kicker {
  color: var(--blue);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.lesson-subtitle {
  max-width: 780px;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.45;
}

.mode-pill {
  min-width: 118px;
  height: 38px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: rgba(255, 255, 255, 0.08);
  color: var(--muted);
  font-weight: 800;
  font-size: 13px;
}

.lesson-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  gap: 22px;
  align-items: stretch;
  min-height: 320px;
  overflow: hidden;
}

.reading-card,
.activity-card,
.quiz-card,
.final-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(5, 13, 23, 0.34);
}

.reading-card {
  padding: 26px 30px;
  overflow: auto;
}

.story-block {
  display: grid;
  gap: 18px;
}

.story-block p {
  color: var(--soft);
  font-size: 18px;
  line-height: 1.55;
  max-width: 900px;
}

.takeaway {
  margin-top: 18px;
  padding: 16px 18px;
  border-left: 4px solid var(--yellow);
  color: var(--ink);
  background: rgba(255, 202, 58, 0.08);
  font-size: 18px;
  line-height: 1.45;
}

.practice-lab {
  margin-top: 20px;
  padding: 18px;
  border: 1px solid rgba(65, 211, 138, 0.3);
  border-left: 4px solid var(--green);
  border-radius: 8px;
  background: rgba(65, 211, 138, 0.08);
}

.practice-lab > span {
  display: block;
  margin-bottom: 8px;
  color: var(--green);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.practice-lab h3 {
  margin-bottom: 8px;
  font-size: 19px;
}

.practice-lab p {
  margin: 0;
  color: var(--soft);
  font-size: 16px;
  line-height: 1.48;
}

.stage-actions {
  padding-top: 8px;
}

.visual-panel {
  padding: 24px;
  display: grid;
  align-content: start;
  gap: 18px;
  overflow: auto;
  background:
    radial-gradient(circle at 80% 20%, rgba(25, 168, 232, 0.2), transparent 32%),
    rgba(5, 13, 23, 0.26);
}

.mini-map {
  display: grid;
  gap: 12px;
}

.map-node {
  padding: 14px 14px 14px 18px;
  border-left: 4px solid var(--blue);
  background: rgba(255, 255, 255, 0.055);
  border-radius: 8px;
}

.map-node:nth-child(2) { border-left-color: var(--yellow); }
.map-node:nth-child(3) { border-left-color: var(--coral); }
.map-node:nth-child(4) { border-left-color: var(--green); }

.map-node strong {
  display: block;
  margin-bottom: 4px;
}

.map-node span {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.35;
}

.framework-section {
  margin-top: 20px;
  padding: 20px;
  border: 1px solid rgba(255, 202, 58, 0.28);
  border-radius: 8px;
  background: linear-gradient(160deg, rgba(255, 202, 58, 0.11), rgba(25, 168, 232, 0.07));
}

.framework-header {
  margin-bottom: 16px;
}

.framework-header h3 {
  margin-bottom: 6px;
}

.framework-header p {
  margin-bottom: 0;
  color: var(--muted);
  line-height: 1.4;
}

.framework-label {
  display: inline-block;
  margin-bottom: 8px;
  color: var(--yellow);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.task-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.task-card {
  min-height: 132px;
  padding: 14px;
  border-radius: 8px;
  background: rgba(5, 13, 23, 0.4);
  border: 1px solid var(--line);
}

.task-card strong {
  display: block;
  color: var(--blue);
  font-size: 32px;
  line-height: 1;
  margin-bottom: 10px;
}

.task-card:nth-child(2) strong { color: var(--yellow); }
.task-card:nth-child(3) strong { color: var(--coral); }
.task-card:nth-child(4) strong { color: var(--green); }

.task-card span {
  display: block;
  color: var(--ink);
  font-weight: 900;
  margin-bottom: 8px;
}

.task-card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.35;
}

.prompt-example {
  display: grid;
  gap: 8px;
  margin-top: 14px;
  padding: 14px;
  border-left: 4px solid var(--yellow);
  background: rgba(5, 13, 23, 0.34);
  color: var(--soft);
  line-height: 1.42;
}

.timeline {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  margin-top: 18px;
}

.timeline button {
  min-height: 120px;
  padding: 14px;
  border-radius: 8px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--line);
  text-align: left;
}

.timeline button.is-selected {
  border-color: var(--yellow);
  background: rgba(255, 202, 58, 0.11);
}

.timeline-year {
  display: block;
  color: var(--yellow);
  font-size: 22px;
  font-weight: 800;
  margin-bottom: 8px;
}

.timeline-detail {
  margin-top: 18px;
  padding: 18px;
  border-radius: 8px;
  background: rgba(25, 168, 232, 0.1);
  color: var(--soft);
  font-size: 18px;
  line-height: 1.5;
}

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

.flashcard {
  min-height: 168px;
  padding: 18px;
  border-radius: 8px;
  background: var(--panel-2);
  color: var(--ink);
  border: 1px solid var(--line);
  text-align: left;
  display: grid;
  align-content: space-between;
}

.flashcard strong {
  font-size: 21px;
}

.flashcard span {
  color: var(--muted);
  line-height: 1.42;
}

.flashcard .flip-hint {
  color: var(--yellow);
  font-size: 13px;
  font-weight: 800;
}

.micro-quiz,
.final-quiz {
  display: grid;
  gap: 18px;
}

.question {
  padding: 20px;
}

.question p {
  font-size: 20px;
  line-height: 1.4;
}

.answer-list {
  display: grid;
  gap: 10px;
}

.answer {
  width: 100%;
  min-height: 48px;
  padding: 12px 14px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.065);
  color: var(--soft);
  border: 1px solid var(--line);
  text-align: left;
}

.answer:hover,
.answer:focus-visible {
  outline: 2px solid rgba(25, 168, 232, 0.5);
  outline-offset: 2px;
}

.answer.is-correct {
  background: rgba(65, 211, 138, 0.14);
  border-color: rgba(65, 211, 138, 0.75);
  color: var(--ink);
}

.answer.is-wrong {
  background: rgba(241, 91, 97, 0.14);
  border-color: rgba(241, 91, 97, 0.75);
  color: var(--ink);
}

.feedback {
  min-height: 44px;
  color: var(--soft);
  line-height: 1.45;
}

.hidden {
  display: none !important;
}

.completion-note {
  color: var(--muted);
  line-height: 1.5;
}

.quiz-layout {
  padding: 38px;
  display: grid;
  grid-template-columns: 390px minmax(0, 1fr);
  gap: 28px;
  min-height: calc(100vh - 56px);
}

.final-card {
  padding: 28px;
}

.score-panel {
  background-image: linear-gradient(rgba(5, 13, 23, 0.42), rgba(5, 13, 23, 0.9)), url("./assets/ai-learning-journey.png");
  background-size: cover;
  background-position: center;
}

.score-number {
  font-size: 68px;
  font-weight: 900;
  line-height: 1;
  margin: 24px 0 10px;
}

.complete-screen {
  position: relative;
  min-height: calc(100vh - 56px);
  padding: 64px;
  display: grid;
  place-items: center;
  overflow: hidden;
  background-image: linear-gradient(180deg, rgba(5, 13, 23, 0.45), rgba(5, 13, 23, 0.95)), url("./assets/ai-learning-journey.png");
  background-size: cover;
  background-position: center;
}

.complete-card {
  position: relative;
  z-index: 1;
  width: min(720px, 100%);
  padding: 44px;
  border: 1px solid rgba(168, 198, 219, 0.26);
  border-radius: 8px;
  background: rgba(7, 21, 35, 0.84);
  box-shadow: var(--shadow);
  text-align: center;
  backdrop-filter: blur(18px);
}

.complete-card h1,
.complete-card .lead {
  margin-left: auto;
  margin-right: auto;
}

.complete-score {
  margin: 32px auto;
  padding: 24px;
  border: 1px solid rgba(65, 211, 138, 0.38);
  border-radius: 8px;
  background: rgba(65, 211, 138, 0.1);
}

.complete-score span {
  display: block;
  font-size: 76px;
  line-height: 1;
  font-weight: 900;
}

.complete-score small {
  display: block;
  max-width: 520px;
  margin: 12px auto 0;
  color: var(--soft);
  font-size: 16px;
  line-height: 1.45;
}

.complete-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

.fireworks {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.fireworks span {
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color);
  box-shadow:
    0 -34px 0 var(--color),
    24px -24px 0 var(--color),
    34px 0 0 var(--color),
    24px 24px 0 var(--color),
    0 34px 0 var(--color),
    -24px 24px 0 var(--color),
    -34px 0 0 var(--color),
    -24px -24px 0 var(--color);
  opacity: 0;
  transform: scale(0.15);
  animation: firework 1.7s ease-out var(--delay) infinite;
}

@keyframes firework {
  0% {
    opacity: 0;
    transform: scale(0.15);
  }

  18% {
    opacity: 1;
  }

  76% {
    opacity: 0.72;
  }

  100% {
    opacity: 0;
    transform: scale(1.15);
  }
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translateX(-50%) translateY(20px);
  max-width: calc(100vw - 32px);
  padding: 12px 16px;
  border-radius: 8px;
  background: #f7fbff;
  color: #071523;
  font-weight: 800;
  opacity: 0;
  pointer-events: none;
  transition: opacity 180ms ease, transform 180ms ease;
  box-shadow: var(--shadow);
}

.toast.is-visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

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

  .side-rail {
    position: static;
    height: auto;
  }

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

  .lesson {
    min-height: auto;
    height: auto;
  }

  .lesson-body,
  .quiz-layout {
    grid-template-columns: 1fr;
  }

  .hero,
  .lesson,
  .quiz-layout,
  .complete-screen {
    padding: 28px;
  }

  .course-hero {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .course-intro h1 {
    font-size: 46px;
  }

  .course-guidance {
    margin-top: -8px;
  }

  h1 {
    font-size: 46px;
  }

  .flashcard-grid,
  .timeline,
  .task-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 620px) {
  body {
    background: #071523;
  }

  .app-shell {
    display: block;
    min-height: 100vh;
  }

  .main-stage {
    padding: 12px 10px 18px;
  }

  .side-rail {
    position: sticky;
    top: 0;
    z-index: 20;
    height: auto;
    padding: 10px 10px 8px;
    gap: 8px;
    min-width: 0;
    max-width: 100vw;
    overflow: hidden;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    background: rgba(5, 13, 23, 0.96);
    backdrop-filter: blur(16px);
    box-shadow: 0 12px 28px rgba(0, 0, 0, 0.26);
  }

  .brand {
    min-height: 36px;
    justify-content: space-between;
    font-size: 15px;
  }

  .brand > span:last-child {
    display: none;
  }

  .brand-mark {
    width: 30px;
    height: 30px;
  }

  .brand-mark span {
    width: 13px;
    height: 13px;
  }

  .brand-mark span:nth-child(1) { left: 9px; }
  .brand-mark span:nth-child(2) { top: 9px; }
  .brand-mark span:nth-child(3) { top: 9px; }
  .brand-mark span:nth-child(4) { left: 9px; }
  .brand-mark span:nth-child(5) {
    left: 9px;
    top: 9px;
    width: 12px;
    height: 12px;
    border-width: 1px;
  }

  .progress-ring {
    position: absolute;
    top: 10px;
    right: 10px;
    min-height: 36px;
    min-width: 78px;
    padding: 6px 10px;
    border-radius: 999px;
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 4px;
    background: rgba(25, 168, 232, 0.12);
  }

  .progress-ring span {
    font-size: 18px;
  }

  .progress-ring small {
    font-size: 11px;
  }

  .stage-nav {
    display: flex;
    width: 100%;
    min-width: 0;
    max-width: 100%;
    overflow-x: auto;
    gap: 8px;
    padding: 3px 0 4px;
    scroll-snap-type: x proximity;
    scrollbar-width: none;
  }

  .stage-nav::-webkit-scrollbar {
    display: none;
  }

  .stage-tab {
    flex: 0 0 auto;
    min-width: 0;
    width: auto;
    min-height: 38px;
    grid-template-columns: 24px auto;
    padding: 7px 10px;
    border: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.045);
    white-space: nowrap;
    scroll-snap-align: start;
  }

  .stage-tab > span:last-child {
    max-width: 122px;
    overflow: hidden;
    text-overflow: ellipsis;
    font-size: 13px;
  }

  .stage-tab.is-active {
    border-color: rgba(25, 168, 232, 0.58);
    background: rgba(25, 168, 232, 0.18);
  }

  .stage-number {
    width: 24px;
    height: 24px;
    font-size: 12px;
  }

  .stage-view,
  .reading-card,
  .activity-card,
  .quiz-card,
  .final-card,
  .complete-card {
    border-radius: 8px;
  }

  .stage-view {
    min-height: auto;
    border: 0;
    background: transparent;
    box-shadow: none;
    overflow: visible;
  }

  .hero {
    min-height: calc(100vh - 118px);
    padding: 26px 20px;
    align-content: end;
    background-image:
      linear-gradient(180deg, rgba(5, 13, 23, 0.04) 0%, rgba(5, 13, 23, 0.58) 44%, rgba(5, 13, 23, 0.96) 100%),
      url("./assets/ai-learning-journey.png");
    background-position: 58% top;
  }

  .course-hero {
    min-height: auto;
    padding: 28px 16px 22px;
    display: block;
    background-position: 58% top;
  }

  .course-intro h1 {
    font-size: 38px;
  }

  .course-intro .lead {
    font-size: 16px;
  }

  .course-picker {
    grid-template-columns: 1fr;
    gap: 12px;
    margin-top: 26px;
  }

  .course-card {
    min-height: 0;
    padding: 18px;
    gap: 15px;
  }

  .course-card h2 {
    font-size: 25px;
  }

  .course-number {
    font-size: 28px;
  }

  .course-guidance {
    margin: 18px 0 0;
    font-size: 13px;
  }

  .hero-actions,
  .stage-actions,
  .quiz-actions {
    gap: 10px;
    margin-top: 18px;
  }

  .button {
    width: 100%;
    min-height: 50px;
    padding: 0 16px;
  }

  h1 {
    font-size: 40px;
    line-height: 1.04;
    margin-bottom: 14px;
  }

  h2 {
    font-size: 28px;
    line-height: 1.12;
    margin-bottom: 8px;
  }

  h3 {
    font-size: 20px;
  }

  .lead,
  .story-block p {
    font-size: 17px;
    line-height: 1.5;
  }

  .lesson {
    min-height: auto;
    height: auto;
    padding: 16px 0 0;
    display: block;
    scroll-margin-top: 118px;
  }

  .lesson-header {
    display: grid;
    gap: 12px;
    padding: 0 2px 16px;
    border-bottom: 0;
  }

  .lesson-kicker {
    font-size: 12px;
    margin-bottom: 6px;
  }

  .lesson-subtitle {
    font-size: 16px;
    line-height: 1.44;
    margin-bottom: 0;
  }

  .mode-pill {
    justify-self: start;
    min-width: 0;
    height: 32px;
    padding: 0 12px;
    font-size: 12px;
    background: rgba(25, 168, 232, 0.13);
    color: var(--soft);
  }

  .lesson-body {
    display: flex;
    flex-direction: column;
    gap: 12px;
    min-height: 0;
    overflow: visible;
  }

  .reading-card,
  .activity-card,
  .final-card {
    background: rgba(13, 33, 52, 0.82);
    box-shadow: 0 14px 32px rgba(0, 0, 0, 0.2);
  }

  .reading-card {
    padding: 18px 16px;
    overflow: visible;
    scroll-margin-top: 118px;
  }

  .activity-card {
    order: -1;
  }

  .lesson:has(.flashcard-grid) .activity-card,
  .lesson:has(.micro-quiz) .activity-card {
    order: 0;
  }

  .visual-panel {
    padding: 16px;
    gap: 12px;
    overflow: visible;
  }

  .mini-map {
    gap: 9px;
  }

  .map-node {
    padding: 12px 12px 12px 14px;
  }

  .map-node span,
  .task-card p {
    font-size: 13px;
  }

  .takeaway,
  .timeline-detail {
    font-size: 16px;
    line-height: 1.45;
  }

  .practice-lab {
    margin-top: 16px;
    padding: 14px;
  }

  .practice-lab p {
    font-size: 15px;
  }

  .framework-section {
    margin-top: 10px;
    padding: 14px;
  }

  .task-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
  }

  .task-card {
    min-height: 116px;
    padding: 12px;
  }

  .task-card strong {
    font-size: 28px;
    margin-bottom: 8px;
  }

  .prompt-example {
    padding: 12px;
    font-size: 14px;
  }

  .timeline {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    margin-top: 8px;
    padding-bottom: 4px;
    scroll-snap-type: x proximity;
  }

  .timeline button {
    flex: 0 0 142px;
    min-height: 102px;
    padding: 12px;
    scroll-snap-align: start;
  }

  .timeline-year {
    font-size: 19px;
    margin-bottom: 6px;
  }

  .flashcard-grid {
    gap: 10px;
  }

  .flashcard {
    min-height: 132px;
    padding: 16px;
  }

  .flashcard strong {
    font-size: 19px;
  }

  .question {
    padding: 0;
  }

  .question p {
    font-size: 18px;
  }

  .answer {
    min-height: 52px;
    padding: 13px 14px;
  }

  .stage-actions {
    position: sticky;
    bottom: 0;
    z-index: 10;
    margin: 14px -10px 0;
    padding: 10px;
    background: linear-gradient(180deg, rgba(7, 21, 35, 0), rgba(7, 21, 35, 0.94) 24%, rgba(7, 21, 35, 0.98));
  }

  .quiz-layout {
    min-height: auto;
    padding: 0;
    gap: 12px;
    scroll-margin-top: 118px;
  }

  .final-card {
    padding: 18px 16px;
  }

  .score-panel {
    min-height: 220px;
    display: grid;
    align-content: end;
  }

  .score-number {
    font-size: 52px;
    margin: 14px 0 6px;
  }

  .final-quiz {
    gap: 20px;
  }

  .complete-screen {
    min-height: calc(100vh - 118px);
    padding: 18px 10px;
    background-position: 58% top;
  }

  .complete-card {
    padding: 24px 16px;
    text-align: left;
  }

  .complete-card h1 {
    font-size: 38px;
  }

  .complete-card .lead {
    font-size: 16px;
  }

  .complete-score {
    margin: 22px 0;
    padding: 18px;
  }

  .complete-score span {
    font-size: 54px;
  }

  .complete-actions {
    display: grid;
    gap: 10px;
  }

  .fireworks span {
    width: 5px;
    height: 5px;
    box-shadow:
      0 -24px 0 var(--color),
      17px -17px 0 var(--color),
      24px 0 0 var(--color),
      17px 17px 0 var(--color),
      0 24px 0 var(--color),
      -17px 17px 0 var(--color),
      -24px 0 0 var(--color),
      -17px -17px 0 var(--color);
  }

  .toast {
    bottom: 14px;
    width: calc(100vw - 24px);
    text-align: center;
  }
}