* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: #edeef0;
    color: #222;
}
main {
    max-width: 640px;
    margin: 0 auto;
    padding: 16px;
}
h1 { font-size: 20px; margin: 0 0 8px; }
.meta { color: #626d7a; font-size: 14px; }
label { display: block; margin: 12px 0 6px; font-size: 13px; }
textarea {
    width: 100%;
    min-height: 72px;
    padding: 8px;
    border: 1px solid #c5c7cb;
    border-radius: 8px;
    font: inherit;
}
button {
    margin-top: 12px;
    width: 100%;
    padding: 10px;
    border: 0;
    border-radius: 8px;
    background: #0077ff;
    color: #fff;
    font-size: 16px;
}
button:disabled { opacity: 0.6; }
pre {
    margin-top: 16px;
    padding: 12px;
    background: #fff;
    border-radius: 8px;
    white-space: pre-wrap;
    word-break: break-word;
    font-size: 13px;
}