:root {
  --bg-color: #f4f4f9;
  --container-bg: #ffffff;
  --text-color: #333;
  --log-bg: #fff;
  --border-color: #ddd;
}

body.dark-mode {
  --bg-color: #1e1e24;
  --container-bg: #2b2b36;
  --text-color: #e1e1e1;
  --log-bg: #2b2b36;
  --border-color: #444;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: sans-serif;
  padding: 20px;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
  max-width: 500px;
  margin: 0 auto;
  background: var(--container-bg);
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
  transition: background-color 0.3s ease;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.theme-btn {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-color);
  border-radius: 20px;
}

.input-group {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}
input[type="text"] {
  flex-grow: 1;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
}
#sendBtn {
  background-color: #007bff;
  color: white;
  border: none;
  border-radius: 4px;
}

#logs {
  max-height: 200px;
  overflow-y: auto;
  border: 1px solid var(--border-color);
  padding: 10px;
  background: var(--log-bg);
}
.message {
  padding: 8px;
  margin: 5px 0;
  border-radius: 4px;
  font-size: 0.9em;
  color: #333;
}
.sent {
  background-color: #e3f2fd;
  text-align: right;
}
.received {
  background-color: #f1f8e9;
  text-align: left;
}