:root {
      --bg-primary: #0f1f16;
      --bg-secondary: #173420;
      --accent: #5fbf90;
      --text-primary: #f4f7f5;
      --text-secondary: #c7d3cc;
      --border-subtle: rgba(255, 255, 255, 0.08);
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        Helvetica, Arial, sans-serif;
      line-height: 1.6;
      color: var(--text-primary);
      background: linear-gradient(180deg, var(--bg-primary), var(--bg-secondary));
    }

    header {
      padding: 4rem 1.5rem 3rem;
      text-align: center;
      border-bottom: 1px solid var(--border-subtle);
    }

    header h1 {
      margin: 0 0 0.75rem;
      font-size: 2.4rem;
      font-weight: 700;
      letter-spacing: -0.02em;
    }

    header p {
      max-width: 720px;
      margin: 0 auto;
      font-size: 1.1rem;
      color: var(--text-secondary);
    }

    main {
      max-width: 960px;
      margin: 0 auto;
      padding: 3rem 1.5rem 4rem;
    }

    section {
      margin-bottom: 3.5rem;
    }

    section h2 {
      font-size: 1.6rem;
      margin-bottom: 1rem;
      border-left: 4px solid var(--accent);
      padding-left: 0.75rem;
    }

    section h3 {
      font-size: 1.15rem;
      margin-top: 2rem;
      margin-bottom: 0.5rem;
    }

    p {
      margin: 0.5rem 0 1rem;
      color: var(--text-secondary);
    }

    ul {
      margin: 0.5rem 0 1.5rem 1.25rem;
      color: var(--text-secondary);
    }

    a {
      color: var(--accent);
      text-decoration: none;
    }

    a:hover {
      text-decoration: underline;
    }

    /* Top navigation */
    .topbar {
      position: sticky;
      top: 0;
      z-index: 50;
      backdrop-filter: blur(10px);
      background: rgba(15, 31, 22, 0.7);
      border-bottom: 1px solid var(--border-subtle);
    }

    .topbar__inner {
      max-width: 960px;
      margin: 0 auto;
      padding: 0.85rem 1.5rem;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 1rem;
    }

    .brand {
      display: inline-flex;
      align-items: center;
      gap: 0.6rem;
      color: var(--text-primary);
      text-decoration: none;
      font-weight: 700;
      letter-spacing: -0.01em;
      white-space: nowrap;
    }

    .brand__mark {
      width: 30px;
      height: 30px;
      display: grid;
      place-items: center;
      border-radius: 999px;
      background: rgba(95, 191, 144, 0.12);
      border: 1px solid rgba(95, 191, 144, 0.35);
      color: var(--accent);
      font-size: 0.9rem;
      line-height: 1;
    }

    .brand__name {
      font-size: 1rem;
    }

    .nav {
      display: flex;
      gap: 0.35rem;
      flex-wrap: wrap;
      justify-content: flex-end;
    }

    .nav__link {
      padding: 0.45rem 0.7rem;
      border-radius: 10px;
      color: var(--text-secondary);
      text-decoration: none;
      font-size: 0.95rem;
      border: 1px solid transparent;
      transition: background 120ms ease, border-color 120ms ease, color 120ms ease;
    }
    /* Mobile dropdown navigation */
.topbar {
  position: sticky;
  top: 0;
}

.nav-toggle {
  display: none;
  appearance: none;
  border: 1px solid rgba(255, 255, 255, 0.10);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-primary);
  padding: 0.45rem 0.75rem;
  border-radius: 10px;
  font-size: 0.95rem;
  cursor: pointer;
}

.nav-toggle:hover {
  background: rgba(255, 255, 255, 0.10);
}

.nav-mobile {
  display: none;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.5rem 0.9rem;
}

.nav-mobile.is-open {
  display: block;
}

.nav-mobile__link {
  display: block;
  padding: 0.75rem 0.9rem;
  border-radius: 12px;
  color: var(--text-secondary);
  text-decoration: none;
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: rgba(0, 0, 0, 0.18);
  margin-top: 0.6rem;
}

.nav-mobile__link:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.06);
  text-decoration: none;
}

/* Switch to dropdown on small screens */
@media (max-width: 720px) {
  .nav { display: none; }
  .nav-toggle { display: inline-flex; align-items: center; }
}

    .card {
      background: rgba(0, 0, 0, 0.25);
      border: 1px solid var(--border-subtle);
      border-radius: 12px;
      padding: 1.5rem 1.75rem;
    }

    footer {
      border-top: 1px solid var(--border-subtle);
      padding: 2rem 1.5rem;
      text-align: center;
      font-size: 0.85rem;
      color: var(--text-secondary);
    }

    @media (max-width: 600px) {
      header h1 {
        font-size: 2rem;
      }

      section h2 {
        font-size: 1.4rem;
      }
    }