:root {
  color-scheme: light;
  --surface: rgba(255, 255, 255, 0.9);
  --surface-strong: #fbfffd;
  --ink: #15222a;
  --muted: #58656d;
  --line: #ced9d4;
  --accent: #186d67;
  --accent-strong: #0d4b47;
  --accent-soft: #daf2ed;
  --shadow: 0 24px 52px rgba(20, 34, 42, 0.1);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 14px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Manrope", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(72, 179, 155, 0.18), transparent 28%),
    radial-gradient(circle at top right, rgba(88, 126, 201, 0.15), transparent 24%),
    linear-gradient(180deg, #eef7f3 0%, #f5faf8 40%, #fbfdfc 100%);
}

a,
button,
input,
select,
textarea {
  font: inherit;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: -3rem;
  z-index: 20;
  padding: 0.75rem 1rem;
  border-radius: 999px;
  background: var(--accent-strong);
  color: #fff;
}

.skip-link:focus {
  top: 1rem;
}

:focus-visible {
  outline: 3px solid rgba(24, 109, 103, 0.25);
  outline-offset: 3px;
}

.shell {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
}

.site-header {
  padding: 2rem 0 1.4rem;
}

.hero-layout {
  display: grid;
  grid-template-columns: 1.45fr 0.95fr;
  gap: 1.25rem;
  align-items: end;
}

.eyebrow {
  margin: 0 0 0.5rem;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}

h1,
h2,
h3 {
  margin: 0;
  font-family: "Fraunces", serif;
  line-height: 1.06;
}

h1 {
  font-size: clamp(2.2rem, 4.2vw, 4.6rem);
}

h2 {
  font-size: clamp(1.5rem, 2.4vw, 2.2rem);
}

h3 {
  font-size: 1.15rem;
}

.lede,
.section-heading p,
.hero-note,
.status-text {
  color: var(--muted);
}

.lede {
  max-width: 58ch;
  font-size: 1.05rem;
  line-height: 1.75;
}

.panel,
.hero-card {
  border: 1px solid rgba(206, 217, 212, 0.92);
  background: var(--surface);
  backdrop-filter: blur(14px);
  box-shadow: var(--shadow);
}

.hero-card {
  padding: 1.5rem;
  border-radius: var(--radius-xl);
  background:
    linear-gradient(180deg, rgba(252, 255, 254, 0.96), rgba(226, 247, 240, 0.94)),
    var(--surface-strong);
}

.hero-label {
  margin: 0;
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.hero-value {
  margin: 0.55rem 0 0.3rem;
  font-size: 2rem;
}

.lesson-layout {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 1.5rem;
  padding-bottom: 3rem;
}

.lesson-aside {
  position: sticky;
  top: 1rem;
  align-self: start;
}

.toc {
  display: grid;
  gap: 0.45rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.72);
}

.toc a {
  padding: 0.7rem 0.85rem;
  border-radius: 12px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
}

.toc a:hover,
.toc a:focus-visible {
  background: var(--accent-soft);
}

.lesson-main,
.stack {
  display: grid;
  gap: 1rem;
}

.panel {
  padding: 1.35rem;
  border-radius: var(--radius-xl);
}

.section-heading {
  display: grid;
  gap: 0.35rem;
  margin-bottom: 0.9rem;
}

.grid.two-col {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.field {
  display: grid;
  gap: 0.45rem;
}

.field span {
  font-weight: 700;
}

input,
select,
textarea {
  width: 100%;
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: #fff;
  color: var(--ink);
}

textarea {
  resize: vertical;
  line-height: 1.7;
}

.word-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.9rem;
  padding: 0;
  margin: 0;
  border: 0;
}

.word-card,
.task-row {
  display: grid;
  gap: 0.45rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(180deg, #fefffe, #f5fbf8);
}

.tag,
.word-bank span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.2rem;
  padding: 0.4rem 0.72rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-weight: 800;
}

.article-panel {
  overflow: hidden;
}

.video-frame {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: #dceae6;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.85);
}

.video-frame iframe {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 0;
}

.reading-copy {
  display: grid;
  gap: 1rem;
  font-size: 1.02rem;
  line-height: 1.9;
}

.reading-copy p {
  margin: 0;
}

.info-card {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 18px;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, #feffff, #f3fbf9);
}

.info-list {
  margin: 0.8rem 0 0;
  padding-left: 1.2rem;
  display: grid;
  gap: 0.45rem;
}

.word-bank {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-bottom: 0.6rem;
}

.action-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

.button {
  width: fit-content;
  min-width: 14rem;
  padding: 0.95rem 1.2rem;
  border: 0;
  border-radius: 999px;
  font-weight: 800;
  cursor: pointer;
}

.button-primary {
  background: linear-gradient(180deg, var(--accent), var(--accent-strong));
  color: #fff;
}

.button-secondary {
  background: #e7f1ee;
  color: var(--accent-strong);
}

.button[disabled] {
  opacity: 0.7;
  cursor: not-allowed;
}

.results-card {
  margin-top: 1rem;
  padding: 1rem 1.1rem;
  border-radius: 18px;
  border: 1px solid #afd8ca;
  background: #f2fcf8;
}

.status-text {
  margin: 0.8rem 0 0;
  min-height: 1.5rem;
  font-weight: 600;
}

.correct {
  border-color: #72b29e;
  background: linear-gradient(180deg, #fbfffd, #edf9f4);
}

.incorrect {
  border-color: #d2b086;
  background: linear-gradient(180deg, #fffaf4, #fff2e4);
}

.feedback {
  font-size: 0.92rem;
  font-weight: 700;
}

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

@media (max-width: 860px) {
  .hero-layout,
  .lesson-layout,
  .grid.two-col,
  .word-grid {
    grid-template-columns: 1fr;
  }

  .lesson-aside {
    position: static;
  }

  .toc {
    grid-auto-flow: column;
    grid-auto-columns: max-content;
    overflow-x: auto;
  }

  .button {
    width: 100%;
  }
}