body {
  font-family: Arial, sans-serif;
  background: #eef1f5;
  margin: 0;
}
header {
  background: #2c7be5;
  color: white;
  padding: 15px;
  text-align: center;
}
nav a {
  color: white;
  margin: 0 8px;
  text-decoration: none;
}
.container {
  max-width: 600px;
  margin: auto;
  padding: 15px;
}
.post-box, .post {
  background: white;
  padding: 15px;
  margin-top: 10px;
  border-radius: 8px;
}
textarea {
  width: 100%;
  height: 80px;
}
button {
  background: #2c7be5;
  color: white;
  border: none;
  padding: 8px;
  margin-top: 6px;
  border-radius: 5px;
}
.dark {
  background: #121212;
  color: white;
}
.dark .post, .dark .post-box {
  background: #1e1e1e;
}