*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,'Hiragino Sans','Noto Sans JP',sans-serif;background:#fff;color:#111}
.app{padding:28px 22px;max-width:820px;margin:0 auto}
h1{font-size:44px;line-height:1.1;margin:40px 0 18px;font-weight:800}
.note{color:#666;font-size:14px;margin-bottom:14px}
textarea{width:100%;height:320px;border:1px solid #ddd;border-radius:10px;padding:14px;font-size:16px;line-height:1.6;resize:vertical}
button{appearance:none;border:0;border-radius:999px;background:#e5e7eb;color:#111;padding:10px 18px;margin:14px 8px 14px 0;font-size:16px}
button:disabled{opacity:.55}
#output{white-space:pre-wrap;word-break:break-word;background:#f7f7f7;border:1px solid #e5e5e5;border-radius:10px;padding:14px;min-height:120px;font-size:14px;line-height:1.7}