```css
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f7fb;
    color: #222;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    width: 90%;
    max-width: 750px;
    background: white;
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.12);
}

h1 {
    text-align: center;
    margin-bottom: 10px;
    font-size: 32px;
}

p {
    text-align: center;
    color: #666;
    margin-bottom: 25px;
    font-size: 16px;
}

textarea {
    width: 100%;
    height: 130px;
    padding: 15px;
    border: 1px solid #ccc;
    border-radius: 10px;
    resize: vertical;
    font-size: 16px;
    font-family: inherit;
    outline: none;
}

textarea:focus {
    border-color: #555;
}

button {
    display: block;
    width: 100%;
    margin-top: 15px;
    padding: 14px;
    border: none;
    border-radius: 10px;
    background: #222;
    color: white;
    font-size: 17px;
    cursor: pointer;
    transition: 0.2s;
}

button:hover {
    background: #444;
}

#answer {
    margin-top: 25px;
    padding: 20px;
    min-height: 80px;
    background: #f7f7f7;
    border-radius: 10px;
    border-left: 4px solid #222;
    line-height: 1.6;
    font-size: 16px;
}

@media (max-width: 600px) {
    .container {
        width: 95%;
        padding: 25px;
    }

    h1 {
        font-size: 25px;
    }

    textarea {
        height: 110px;
    }
}
```