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

body {
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.7;
  color: #d0d0d0;
  background: #1a1a1a;
  min-height: 100vh;
  padding: 40px 20px;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 60px 80px;
}

header {
  text-align: center;
  margin-bottom: 50px;
  border-bottom: 1px solid #3a3a3a;
  padding-bottom: 30px;
}

h1 {
  font-size: 2.5em;
  font-weight: 400;
  color: #ffffff;
  margin-bottom: 20px;
  letter-spacing: 0.5px;
}

.author {
  font-size: 1.1em;
  color: #b0b0b0;
  margin-bottom: 10px;
}

.website {
  font-size: 1em;
  font-style: italic;
  margin-bottom: 10px;
}

.website a {
  color: #2569E6;
  text-decoration: none;
  transition: color 0.3s ease;
}

.website a:hover {
  color: #2ECBE9;
}

.date {
  font-size: 1em;
  font-style: italic;
  color: #888;
}

.introduction {
  margin-bottom: 40px;
  font-size: 1.05em;
  line-height: 1.8;
  color: #d0d0d0;
}

section {
  margin-bottom: 40px;
}

h2 {
  font-size: 1.5em;
  color: #ffffff;
  margin-bottom: 15px;
  font-weight: 600;
  position: relative;
  padding-bottom: 8px;
}

h2::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 50px;
  height: 2px;
  background: #2569E6;
  transition: width 0.3s ease;
}

section:hover h2::after {
  width: 80px;
}

p {
  font-size: 1.05em;
  line-height: 1.8;
  text-align: justify;
  color: #c0c0c0;
}

.closing {
  margin-top: 60px;
  margin-bottom: 40px;
  font-style: italic;
  font-size: 1.05em;
  color: #a0a0a0;
  line-height: 1.8;
  padding: 20px;
  border-left: 3px solid #2569E6;
  background: rgba(37, 105, 230, 0.05);
}

.signature {
  text-align: right;
  font-style: italic;
  color: #888;
  font-size: 1.05em;
  line-height: 1.8;
}

@media (max-width: 768px) {
  body {
    padding: 30px 20px;
  }

  .container {
    padding: 40px 30px;
  }

  h1 {
    font-size: 2em;
  }

  p,
  .introduction,
  .closing {
    text-align: left;
  }
}

@media (max-width: 480px) {
  body {
    padding: 20px 15px;
  }

  .container {
    padding: 30px 20px;
  }

  header {
    margin-bottom: 35px;
    padding-bottom: 25px;
  }

  h1 {
    font-size: 1.8em;
  }

  h2 {
    font-size: 1.3em;
  }

  p,
  .introduction,
  .closing {
    font-size: 1em;
  }

  .closing {
    padding: 15px;
  }
}