body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    max-width: 600px;
    margin: 40px auto;
    padding: 0 20px;
    line-height: 1.6;
    background-color: #f9f9f9;
    color: #333;
}

h1 {
    color: #111;
    border-bottom: 2px solid #eaeaea;
    padding-bottom: 10px;
}

textarea {
    width: 100%;
    height: 120px;
    font-family: monospace;
    font-size: 14px;
    padding: 10px;
    box-sizing: border-box;
    border: 1px solid #ccc; border-radius: 4px;
}

.controls {
    margin: 15px 0;
    display: flex;
    gap: 15px;
    align-items: center;
}

button {
    background-color: #0066cc;
    color: white;
    border: none;
    padding: 9px 18px;
    font-size: 14px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
}

button:disabled {
    background-color: #aaa;
    cursor: not-allowed;
}

#status {
    font-weight: bold;
    margin-top: 10px;
    color: #cc6600;
}

#result-box {
    margin-top: 20px;
    padding: 15px;
    background: #eef6ff;
    border-left: 4px solid #0066cc;
    border-radius: 0 4px 4px 0;
    display: none;
}