* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #f7f9fc;
  color: #1f2937;
  line-height: 1.65;
}

header {
  background: #1565c0;
  color: white;
  padding: 22px 24px;
}

.header-content {
  max-width: 920px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  font-size: 24px;
  font-weight: 800;
  letter-spacing: 1px;
}

nav {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: 600;
}

main {
  max-width: 920px;
  margin: 0 auto;
  padding: 48px 24px;
}

.hero {
  text-align: center;
  padding: 50px 0 60px;
}

.hero h1 {
  margin: 0 0 12px;
  font-size: 42px;
  color: #1565c0;
}

.hero p {
  max-width: 620px;
  margin: 0 auto;
  font-size: 18px;
  color: #566274;
}

.card {
  background: white;
  border-radius: 18px;
  padding: 28px;
  margin-bottom: 24px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
}

.card h1,
.card h2 {
  color: #1565c0;
}

.card h1 {
  margin-top: 0;
}

.button {
  display: inline-block;
  padding: 13px 20px;
  border-radius: 10px;
  background: #1565c0;
  color: white;
  text-decoration: none;
  font-weight: 700;
}

.button-danger {
  background: #c62828;
}

.notice {
  border-left: 4px solid #1565c0;
  padding: 12px 16px;
  background: #eef6ff;
  margin: 20px 0;
  border-radius: 6px;
}

.warning {
  border-left-color: #c62828;
  background: #fff1f1;
}

footer {
  text-align: center;
  padding: 36px 20px;
  color: #6b7280;
  font-size: 14px;
}

footer a {
  color: #1565c0;
}

@media (max-width: 650px) {
  .header-content {
    flex-direction: column;
    align-items: flex-start;
  }

  .hero h1 {
    font-size: 34px;
  }

  main {
    padding: 32px 16px;
  }

  .card {
    padding: 22px;
  }
}