body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #2e2e2e;
    color: #ffffff;
}

header {
    text-align: center;
    background-color: #1a1a1a;
    color: #4CAF50;
    padding: 20px;
    border-bottom: 2px solid #4CAF50;
}

main {
    max-width: 800px;
    margin: 0 auto;
    background-color: #1a1a1a;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
}

section {
    margin-bottom: 20px;
}

h2 {
    color: #4CAF50;
    border-bottom: 1px solid #4CAF50;
    padding-bottom: 5px;
}

button {
    background-color: #4CAF50;
    color: white;
    border: none;
    padding: 10px 15px;
    cursor: pointer;
    border-radius: 4px;
    font-weight: bold;
}

button:hover {
    background-color: #45a049;
}

input {
    padding: 8px;
    margin: 5px 0;
    width: 100%;
    box-sizing: border-box;
    background-color: #333;
    color: #fff;
    border: 1px solid #555;
    border-radius: 4px;
}

input:focus {
    border-color: #4CAF50;
}

ul {
    list-style-type: none;
    padding: 0;
}

li {
    background-color: #333;
    margin: 5px 0;
    padding: 10px;
    border-radius: 4px;
    border-left: 5px solid #4CAF50;
}

li.send {
    border-left-color: #f44336;
}