:root {
  color-scheme: light;
  --background: #f5f2ea;
  --surface: #fffdf8;
  --surface-strong: #ffffff;
  --text: #1d2823;
  --muted: #66716b;
  --line: #d9ded8;
  --accent: #006d52;
  --accent-soft: #d9efe7;
  --accent-warm: #f2b950;
  --shadow: 0 22px 60px rgba(28, 51, 42, 0.09);
  --radius-large: 28px;
  --radius-medium: 18px;
}

[data-theme="dark"] {
  color-scheme: dark;
  --background: #111815;
  --surface: #18211d;
  --surface-strong: #202b26;
  --text: #edf4ef;
  --muted: #a7b4ad;
  --line: #34423b;
  --accent: #72d5b5;
  --accent-soft: #193f34;
  --accent-warm: #f2bd5c;
  --shadow: 0 22px 60px rgba(0, 0, 0, 0.22);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 85% 5%, color-mix(in srgb, var(--accent-warm) 20%, transparent), transparent 24rem),
    var(--background);
  color: var(--text);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  min-height: 100vh;
}

button,
textarea {
  font: inherit;
}

button {
  color: inherit;
}

.site-header,
main,
footer {
  width: min(1120px, calc(100% - 40px));
  margin-inline: auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 24px;
}

.brand {
  display: inline-flex;
  gap: 11px;
  align-items: center;
  color: var(--text);
  font-weight: 750;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 10px;
  background: var(--text);
  color: var(--background);
}

.icon-button {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--surface);
  cursor: pointer;
}

.icon-button:hover,
.icon-button:focus-visible {
  border-color: var(--accent);
  outline: 3px solid color-mix(in srgb, var(--accent) 18%, transparent);
}

.hero {
  padding: 88px 0 58px;
}

.eyebrow,
.card-kicker {
  margin: 0 0 10px;
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

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

h1 {
  max-width: 820px;
  margin-bottom: 22px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(3.4rem, 9vw, 7.6rem);
  font-weight: 500;
  letter-spacing: -0.065em;
  line-height: 0.92;
}

h2 {
  margin-bottom: 12px;
  font-size: clamp(1.4rem, 2vw, 2rem);
  letter-spacing: -0.035em;
  line-height: 1.15;
}

h3 {
  margin-block: 8px;
  font-size: 1.08rem;
  line-height: 1.3;
}

.hero-copy {
  max-width: 650px;
  margin-bottom: 46px;
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.3rem);
}

.progress-card {
  max-width: 720px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius-medium);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  box-shadow: var(--shadow);
}

.progress-heading {
  display: flex;
  justify-content: space-between;
  margin-bottom: 12px;
}

.progress-track {
  height: 9px;
  overflow: hidden;
  border-radius: 99px;
  background: var(--line);
}

.progress-track span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--accent-warm));
  transition: width 300ms ease;
}

.progress-card p {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.resume-button {
  margin-top: 12px;
  color: var(--accent);
  font-weight: 750;
}

.lesson {
  margin-block: 42px 72px;
  padding: clamp(28px, 5vw, 58px);
  border: 1px solid var(--line);
  border-radius: var(--radius-large);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.lesson[hidden],
.completion-panel[hidden] {
  display: none;
}

.lesson:focus-visible,
.completion-panel:focus-visible {
  outline: 4px solid color-mix(in srgb, var(--accent) 28%, transparent);
  outline-offset: 5px;
}

.lesson.is-complete {
  border-color: color-mix(in srgb, var(--accent) 60%, var(--line));
}

.lesson-heading {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(28px, 6vw, 80px);
  align-items: end;
  margin-bottom: 36px;
}

.lesson-heading h2 {
  max-width: 520px;
  margin-bottom: 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 4vw, 3.5rem);
  font-weight: 500;
}

.lesson-heading > p,
.concept-card p {
  margin-bottom: 0;
  color: var(--muted);
}

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

.concept-card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius-medium);
  background: var(--surface-strong);
}

.concept-card > code,
.lesson-example code,
.lesson-quiz code {
  color: var(--accent);
  font-weight: 750;
}

.lesson-example {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 28px;
  margin-top: 28px;
  padding: 26px;
  border-radius: var(--radius-medium);
  background: var(--accent-soft);
}

.lesson-example ol {
  margin: 0;
  padding-left: 22px;
}

.lesson-example li + li {
  margin-top: 8px;
}

.lesson-note {
  margin-top: 18px;
  padding: 16px 18px;
  border-left: 4px solid var(--accent);
  border-radius: 0 12px 12px 0;
  background: color-mix(in srgb, var(--accent-soft) 45%, var(--surface));
}

.lesson-note-warning {
  border-left-color: var(--accent-warm);
  background: color-mix(in srgb, var(--accent-warm) 15%, var(--surface));
}

.lesson-quiz {
  margin-top: 28px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.lesson-quiz fieldset {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  border: 0;
}

.lesson-quiz legend {
  margin-bottom: 14px;
  font-weight: 750;
}

.lesson-quiz label {
  display: flex;
  gap: 10px;
  align-items: center;
  width: fit-content;
  cursor: pointer;
}

.lesson-quiz input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

.quiz-actions {
  display: flex;
  gap: 18px;
  align-items: center;
  margin-top: 22px;
}

.primary-button {
  display: inline-block;
  border: 0;
  border-radius: 12px;
  padding: 12px 18px;
  background: var(--text);
  color: var(--background);
  font-weight: 750;
  cursor: pointer;
  text-decoration: none;
}

.primary-button:hover,
.primary-button:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 25%, transparent);
}

.quiz-feedback {
  min-height: 1.6em;
  margin: 0;
  color: var(--muted);
  font-weight: 700;
}

.quiz-feedback[data-result="correct"] {
  color: var(--accent);
}

.completion-panel {
  margin-block: 42px 72px;
  padding: clamp(32px, 6vw, 68px);
  border-radius: var(--radius-large);
  background: var(--text);
  color: var(--background);
  text-align: center;
}

.completion-panel h2 {
  margin-inline: auto;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 5vw, 4rem);
  font-weight: 500;
}

.completion-panel p:not(.eyebrow) {
  max-width: 680px;
  margin: 0 auto 24px;
  color: color-mix(in srgb, var(--background) 78%, transparent);
}

.completion-panel .primary-button {
  background: var(--accent-warm);
  color: #1d2823;
}

.learning-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  padding-block: 42px;
}

.learning-card {
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: 330px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius-large);
  background: var(--surface);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.35) inset;
}

.learning-card:has(input:checked) {
  border-color: color-mix(in srgb, var(--accent) 60%, var(--line));
  background: color-mix(in srgb, var(--accent-soft) 54%, var(--surface));
}

.learning-card.is-locked {
  opacity: 0.62;
}

.step-number {
  display: block;
  margin-bottom: 42px;
  color: var(--muted);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.5rem;
}

.learning-card p:not(.card-kicker) {
  color: var(--muted);
}

.task-check {
  display: flex;
  gap: 10px;
  align-items: center;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-weight: 700;
  cursor: default;
}

.task-check input {
  width: 20px;
  height: 20px;
  accent-color: var(--accent);
}

.module-link {
  justify-self: start;
  margin-top: 14px;
  color: var(--accent);
  font-weight: 750;
}

.module-link:disabled {
  color: var(--muted);
  cursor: not-allowed;
  opacity: 0.75;
}

.toolbox,
.notes {
  display: grid;
  grid-template-columns: 0.75fr 1.25fr;
  gap: 70px;
  margin-block: 72px;
  padding: clamp(28px, 5vw, 58px);
  border-radius: var(--radius-large);
}

.toolbox {
  background: var(--text);
  color: var(--background);
}

.toolbox .eyebrow {
  color: var(--accent-warm);
}

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

.command {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 14px 16px;
  border: 1px solid color-mix(in srgb, var(--background) 22%, transparent);
  border-radius: 12px;
  background: color-mix(in srgb, var(--background) 8%, transparent);
  color: inherit;
  cursor: pointer;
  text-align: left;
}

.command:hover,
.command:focus-visible {
  border-color: var(--accent-warm);
  outline: none;
}

.command span {
  color: color-mix(in srgb, var(--background) 65%, transparent);
  font-size: 0.82rem;
}

.copy-feedback {
  grid-column: 2;
  min-height: 1.5em;
  margin: 0;
  color: var(--accent-warm);
  font-size: 0.9rem;
}

.notes {
  align-items: start;
  border: 1px solid var(--line);
  background: var(--surface);
}

.notes > div:first-child > p:last-child {
  color: var(--muted);
}

textarea {
  width: 100%;
  resize: vertical;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px;
  background: var(--surface-strong);
  color: var(--text);
}

textarea:focus {
  border-color: var(--accent);
  outline: 3px solid color-mix(in srgb, var(--accent) 18%, transparent);
}

.notes-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.85rem;
}

.text-button {
  border: 0;
  border-bottom: 1px solid currentColor;
  padding: 2px 0;
  background: transparent;
  cursor: pointer;
}

footer {
  padding-block: 28px 46px;
  border-top: 1px solid var(--line);
  color: var(--muted);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

@media (max-width: 760px) {
  .site-header,
  main,
  footer {
    width: min(100% - 26px, 1120px);
  }

  .hero {
    padding-top: 58px;
  }

  .learning-grid,
  .lesson-heading,
  .concept-grid,
  .lesson-example,
  .toolbox,
  .notes {
    grid-template-columns: 1fr;
  }

  .learning-card {
    min-height: 300px;
  }

  .toolbox,
  .notes {
    gap: 28px;
  }

  .copy-feedback {
    grid-column: 1;
  }

  .command span {
    display: none;
  }

  .quiz-actions {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}