:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-text: #222222;
  --color-muted: #5f6673;
  --color-border: #dfe4ea;
  --color-surface: #f8fafc;
  --color-background: #ffffff;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--color-background);
}

body {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px;
  color: var(--color-text);
  background: var(--color-background);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.7;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.16s ease, border-color 0.16s ease, background-color 0.16s ease;
}

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--color-border);
}

.brand {
  color: var(--color-text);
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0;
}

.brand:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.site-nav,
.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.site-nav a,
.site-footer a {
  font-size: 0.95rem;
}

.site-nav a[aria-current="page"] {
  color: var(--color-text);
  font-weight: 700;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(220px, 0.8fr);
  gap: 28px;
  align-items: center;
  padding: 56px 0 40px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--color-primary);
  font-size: 0.88rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  color: var(--color-text);
  line-height: 1.25;
}

h1 {
  margin: 0;
  font-size: clamp(2.4rem, 7vw, 4.5rem);
  letter-spacing: 0;
}

h2 {
  margin: 2rem 0 0.75rem;
  font-size: 1.45rem;
}

p {
  margin: 0 0 1rem;
}

ul {
  margin: 0.5rem 0 1.25rem;
  padding-left: 1.4rem;
}

li + li {
  margin-top: 0.35rem;
}

.subtitle {
  margin: 8px 0 16px;
  font-size: 1.45rem;
  font-weight: 700;
}

.intro {
  max-width: 38rem;
  color: var(--color-muted);
  font-size: 1.08rem;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid var(--color-primary);
  border-radius: 999px;
  color: #ffffff;
  background: var(--color-primary);
  font-weight: 700;
}

.button:hover {
  color: #ffffff;
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  text-decoration: none;
}

.button-secondary {
  color: var(--color-primary);
  background: #ffffff;
}

.button-secondary:hover {
  color: var(--color-primary-dark);
  background: #eff6ff;
}

.app-preview {
  border: 1px solid var(--color-border);
  border-radius: 28px;
  padding: 14px;
  background: var(--color-surface);
  box-shadow: 0 18px 48px rgba(37, 99, 235, 0.12);
}

.preview-topbar {
  width: 72px;
  height: 6px;
  margin: 4px auto 16px;
  border-radius: 999px;
  background: #cbd5e1;
}

.word-card {
  min-height: 220px;
  border-radius: 20px;
  padding: 20px;
  background: #ffffff;
  border: 1px solid var(--color-border);
}

.word-card h2 {
  margin: 12px 0 8px;
  font-size: 2rem;
}

.tag {
  display: inline-flex;
  padding: 4px 10px;
  border-radius: 999px;
  color: var(--color-primary);
  background: #eff6ff;
  font-size: 0.82rem;
  font-weight: 700;
}

.example {
  color: var(--color-muted);
  font-size: 0.95rem;
}

.section {
  padding: 10px 0 32px;
}

.feature-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  padding: 0;
  list-style: none;
}

.feature-list li {
  margin: 0;
  padding: 14px 16px;
  border: 1px solid var(--color-border);
  border-radius: 16px;
  background: var(--color-surface);
}

.document {
  padding: 36px 0 24px;
}

.page-title {
  margin-bottom: 28px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--color-border);
}

.page-title h1 {
  font-size: clamp(2rem, 6vw, 3rem);
}

.page-title p {
  margin-top: 10px;
  color: var(--color-muted);
}

.document section {
  margin-bottom: 28px;
}

.document section h2 {
  margin-top: 0;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
  color: var(--color-muted);
}

.site-footer p {
  margin: 0;
}

@media (max-width: 720px) {
  body {
    padding: 20px;
  }

  .site-header,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero {
    grid-template-columns: 1fr;
    padding-top: 40px;
  }

  .app-preview {
    max-width: 360px;
  }

  .feature-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 420px) {
  body {
    padding: 18px;
  }

  .actions {
    flex-direction: column;
  }

  .button {
    width: 100%;
  }
}