static/styles.css

body {
    font-family: Arial, sans-serif;
    background-color: #f2f2f2;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: auto;
    background-color: #fff;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

header {
    margin-bottom: 20px;
}

header nav a {
    margin-right: 10px;
    text-decoration: none;
    color: #007BFF;
}

.flashes {
    list-style: none;
    padding: 0;
}

.flash {
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 4px;
}

.flash.error {
    background-color: #f8d7da;
    color: #721c24;
}

.flash.success {
    background-color: #d4edda;
    color: #155724;
}

.thread-list, .message-list {
    list-style: none;
    padding: 0;
}

.thread-list li, .message-list li {
    padding: 10px;
    border-bottom: 1px solid #ddd;
}

.message {
    padding: 10px;
    background-color: #fafafa;
    border: 1px solid #ddd;
    border-radius: 4px;
}

.message-actions form, .message-actions button {
    display: inline;
    margin-right: 5px;
}

#preview-area {
    border: 1px dashed #aaa;
    padding: 10px;
    margin-top: 10px;
}