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

body {
  font-family: 'Segoe UI', sans-serif;
  background: #f8fafc;
  color: #1f2937;
}

.header {
  background: linear-gradient(135deg, #1e3a5f, #2563eb);
  color: white;
  padding: 16px 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header nav a {
  color: white;
  text-decoration: none;
  margin-left: 20px;
  font-size: 0.95rem;
  opacity: 0.85;
  transition: opacity 0.2s;
}
.header nav a:hover { opacity: 1; }

.hero {
  text-align: center;
  padding: 80px 20px;
}

.hero h2 { font-size: 2.5rem; margin-bottom: 16px; }
.highlight { color: #2563eb; }

.hero p { color: #6b7280; font-size: 1.1rem; margin-bottom: 32px; }

.btn {
  background: linear-gradient(to right, #2563eb, #7c3aed);
  color: white;
  border: none;
  padding: 14px 32px;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: bold;
  cursor: pointer;
  transition: opacity 0.2s;
}
.btn:hover { opacity: 0.9; }

.result-box {
  margin: 24px auto;
  max-width: 500px;
  min-height: 50px;
  background: white;
  border-radius: 12px;
  padding: 16px;
  border: 1px solid #e5e7eb;
  color: #374151;
}

.features { padding: 60px 20px; background: white; }
.features h2 { text-align: center; font-size: 1.8rem; margin-bottom: 32px; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  max-width: 800px;
  margin: 0 auto;
}

.card {
  background: #f0f4ff;
  border-radius: 16px;
  padding: 24px;
  text-align: center;
  font-weight: 600;
  color: #1e40af;
  border: 1px solid #c7d2fe;
}