:root {
  --primary: #2563eb;
  --dark: #0f172a;
  --bg: #f8fafc;
  --card: #ffffff;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Poppins', sans-serif;
  background: var(--bg);
  color: var(--dark);
  padding: 40px 20px;
}

h1 {
  text-align: center;
  font-size: 2.3rem;
  font-weight: 800;
}

.subtitle {
  text-align: center;
  max-width: 650px;
  margin: 10px auto 45px;
  color: #64748b;
  font-size: 0.95rem;
}

.grid {
  display: flex;
  flex-direction: column;
  gap: 25px;
  max-width: 900px;
  margin: auto;
}

.card {
  background: var(--card);
  border-radius: 16px;
  padding: 22px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.08);
  transition: 0.3s ease;
  border: 1px solid #e2e8f0;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 15px 30px rgba(0,0,0,0.1);
}

.cert-info h3 {
  font-size: 1.3rem;
  margin-bottom: 6px;
}

.cert-info p {
  font-size: 0.85rem;
  color: #64748b;
  margin-bottom: 15px;
}

.chapter {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid #e2e8f0;
  font-size: 0.9rem;
}

.chapter:last-child {
  border-bottom: none;
}

.btn-link {
  padding: 6px 12px;
  border-radius: 8px;
  font-weight: 600;
  text-decoration: none;
  font-size: 0.8rem;
  border: 2px solid #e2e8f0;
  color: var(--dark);
  transition: 0.2s;
}

.btn-link:hover {
  background: #f1f5f9;
}

footer {
  margin-top: 70px;
  text-align: center;
  padding-top: 20px;
  border-top: 1px solid #e2e8f0;
}

.socials {
  margin-top: 10px;
}

.socials a {
  margin: 0 12px;
  text-decoration: none;
  color: var(--dark);
  font-weight: 600;
  font-size: 0.9rem;
}

.socials a:hover {
  color: var(--primary);
}

.flex-text {
  margin-top: 10px;
  font-size: 0.85rem;
  color: #64748b;
}

@media (max-width: 500px) {
  h1 {
    font-size: 1.9rem;
  }
}