body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  margin: 0;
  padding: 0;
}
.container {
  background: #fff;
  max-width: 400px;
  margin: 40px auto;
  padding: 30px 40px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
h1, h2 {
  text-align: center;
}
nav {
  text-align: center;
  margin-bottom: 20px;
}
nav a {
  margin: 0 10px;
  color: #0077cc;
  text-decoration: none;
}
nav a:hover {
  text-decoration: underline;
}
input, textarea, button {
  width: 100%;
  margin: 8px 0;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
}
button {
  background: #0077cc;
  color: #fff;
  border: none;
  cursor: pointer;
  font-weight: bold;
}
button:hover {
  background: #005fa3;
}
.error {
  color: #d8000c;
  text-align: center;
}
#inboxList {
  margin-top: 20px;
}
.email-item {
  border-bottom: 1px solid #eee;
  padding: 10px 0;
}
.email-item:last-child {
  border-bottom: none;
}
.email-item strong {
  color: #0077cc;
}