```html
body {
fontfamily: Arial, sansserif;
margin: 0;
padding: 20px;
}
h1 {
textalign: center;
}
.calculator {
width: 400px;
margin: 0 auto;
padding: 20px;
border: 1px solid ccc;
borderradius: 5px;
}
.formgroup {
marginbottom: 20px;
}
label {
display: block;
marginbottom: 5px;
}
input[type="number"] {
width: 100%;
padding: 5px;
border: 1px solid ccc;
borderradius: 3px;
}
button {
padding: 10px 20px;
backgroundcolor: 007BFF;
color: white;
border: none;
cursor: pointer;
borderradius: 3px;
transition: backgroundcolor 0.3s;
}
.result {
textalign: center;
margintop: 20px;
}
function calculate() {
const initialAmount = parseFloat(document.getElementById('initial_amount').value);
const annualInterestRate = parseFloat(document.getElementById('annual_interest_rate').value);
const years = parseInt(document.getElementById('years').value);
// 理财余额计算公式: P(1 r/n)^(nt) P = P * (1 r/n)^(nt) P
// 其中: P = 初始金额, r = 年化收益率, n = 每年复利次数(通常为1年),t = 投资年限
const balance = initialAmount * Math.pow(1 annualInterestRate / 1, years) initialAmount;
document.getElementById('balance').innerText = `最终余额: ${balance.toFixed(2)}元`;
}