body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #111827;
  color: #f9fafb;
  line-height: 1.7;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 20px 60px;
}

h1, h2 {
  color: #22d3ee;
  margin-top: 0;
}

h1 {
  font-size: 34px;
  margin-bottom: 24px;
}

h2 {
  font-size: 24px;
  margin-top: 32px;
  margin-bottom: 12px;
}

p, li {
  font-size: 18px;
}

ul {
  padding-right: 22px;
  margin: 0 0 14px;
}

li {
  margin-bottom: 8px;
}

.card {
  border-radius: 16px;
  padding: 24px;
  margin-bottom: 20px;
}

a {
  color: #93c5fd;
}

.note {
  background: #3f1d1d;
  border-right: 5px solid #f87171;
  padding: 16px;
  border-radius: 12px;
  margin-top: 16px;
}

.back-link {
  display: inline-block;
  margin-top: 30px;
  padding: 12px 18px;
  border-radius: 10px;
  background: #0f766e;
  color: #fff;
  text-decoration: none;
}

.back-link:hover,
.back-link:focus {
  background: #115e59;
}

/* footer */
footer {
    text-align: center;
    padding: 24px 20px;
    background: #263845;
}

footer p {
    margin: 8px 0;
    font-size: 17px;
    line-height: 1.6;
}

footer a {
    color: #ffffff;
    text-decoration: underline;
}

@media (max-width: 768px) {
  .container {
    padding: 28px 16px 50px;
  }

  h1 {
    font-size: 28px;
    margin-bottom: 18px;
  }

  h2 {
    font-size: 22px;
    margin-top: 24px;
  }

  p, li {
    font-size: 17px;
  }

  .card {
    padding: 18px;
    border-radius: 14px;
  }

  .back-link {
    width: 100%;
    text-align: center;
    box-sizing: border-box;
  }
}