:root {
  --bg: #f8f4ec;
  --bg-soft: #fefcf8;
  --hero-accent: linear-gradient(180deg, #ffe8c7 0%, #f8f4ec 100%);
  --card: #ffffff;
  --ink: #1f2a37;
  --muted: #5c6070;
  --accent: #c0522f;
  --accent-strong: #963515;
  --accent-soft: #ffe7d3;
  --border: #e5d6c5;
  --font-body: "Work Sans", "Segoe UI", sans-serif;
  --font-heading: "Newsreader", Georgia, serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
}

.container {
  width: min(1000px, 92vw);
  margin: 0 auto;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 12px;
  background: var(--accent);
  color: #fff;
  padding: 0.5rem 1rem;
  border-radius: 999px;
  text-decoration: none;
}

.skip-link:focus {
  left: 12px;
}

.hero {
  background: var(--hero-accent);
  padding: clamp(2.5rem, 8vw, 4.5rem) 0;
}

.home-link {
  display: inline-flex;
  align-items: center;
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.home-link:hover {
  text-decoration: underline;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.82rem;
  color: var(--accent-strong);
  margin: 0.75rem 0 0.5rem;
}

h1,
h2,
h3 {
  font-family: var(--font-heading);
  line-height: 1.2;
  margin-top: 0;
  color: var(--ink);
}

h1 {
  font-size: clamp(2.1rem, 4vw, 3.2rem);
  margin-bottom: 0.85rem;
}

h2 {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  margin-bottom: 0.65rem;
}

h3 {
  font-size: clamp(1.2rem, 2.2vw, 1.45rem);
}

.hero-lead {
  color: var(--muted);
  max-width: 760px;
  font-size: 1.08rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.2rem 0;
}

.cta {
  border-radius: 999px;
  padding: 0.8rem 1.3rem;
  border: none;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.cta:hover {
  transform: translateY(-2px);
}

.cta.primary {
  background: var(--accent);
  color: #fff9f5;
  box-shadow: 0 12px 24px rgba(192, 82, 47, 0.3);
}

.cta.secondary {
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.cta.tertiary {
  background: #fff;
  border: 1px solid var(--border);
  color: var(--accent-strong);
}

.hero-badges {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin: 0;
  padding: 0;
}

.hero-badges li {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.45rem 0.85rem;
  font-weight: 600;
  color: var(--accent-strong);
}

.section {
  padding: clamp(2.5rem, 8vw, 4.75rem) 0;
}

.section.muted {
  background: var(--bg-soft);
}

.section-lead {
  color: var(--muted);
  margin-bottom: 1.5rem;
}

.concept-grid,
.lab-grid,
.practice-layout {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 1.35rem;
  box-shadow: 0 12px 24px rgba(20, 26, 39, 0.07);
}

.card ul {
  padding-left: 1.1rem;
  margin: 0.8rem 0 0;
}

.form-row {
  display: grid;
  gap: 0.3rem;
  margin-bottom: 0.75rem;
}

label {
  font-size: 0.92rem;
  color: var(--muted);
}

input {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.55rem 0.65rem;
  font: inherit;
}

.triplet-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.5rem;
}

.small-note {
  color: var(--muted);
  margin-top: 0.75rem;
}

.graph-card {
  align-items: start;
}

canvas {
  border: 1px solid var(--border);
  border-radius: 12px;
  width: 100%;
  max-width: 360px;
  height: auto;
  background: #fff;
}

.skill-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.skill-btn {
  border: 1px solid var(--border);
  background: #fff;
  color: var(--accent-strong);
  border-radius: 999px;
  padding: 0.5rem 0.8rem;
  font-weight: 600;
  cursor: pointer;
}

.skill-btn.is-active {
  background: var(--accent-soft);
  border-color: rgba(192, 82, 47, 0.35);
}

.stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.6rem;
  margin: 1rem 0 0;
}

.stats div {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.5rem;
}

.stats dt {
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.stats dd {
  margin: 0.2rem 0 0;
  font-weight: 700;
}

.stars {
  margin-top: 0.75rem;
  font-weight: 600;
}

.choice-list {
  display: grid;
  gap: 0.5rem;
  margin-bottom: 0.8rem;
}

.choice-btn {
  text-align: left;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 10px;
  padding: 0.6rem;
  cursor: pointer;
}

.choice-btn.is-selected {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.actions-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.4rem;
}

.feedback {
  min-height: 1.5rem;
  font-weight: 600;
  margin-top: 0.8rem;
}

.feedback.ok {
  color: #206b2a;
}

.feedback.bad {
  color: #9a1f1f;
}

.footer {
  border-top: 1px solid var(--border);
  background: #f4ebe0;
  padding: 2.2rem 0;
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

@media (max-width: 640px) {
  .triplet-grid,
  .stats {
    grid-template-columns: 1fr;
  }

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