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

body {
    font-family: "Microsoft YaHei", sans-serif;
    background: #f5f7fa;
}

.top-nav {
    background: #2d8cf0;
    padding: 30px 0;
    text-align: center;
}

.top-nav h1 {
    color: white;
    font-size: 24px;
}

.content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.two-columns {
    display: -ms-grid;
    display: grid;
    -ms-grid-columns: 1fr 20px 1fr;
    grid-template-columns: repeat(2, 1fr);
    grid-gap: 20px;
    gap: 20px;
}

.tool-box {
    background: white;
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 2px 10px #eee;
}

.tool-title {
    font-size: 18px;
    color: #2d8cf0;
    border-left: 4px solid #2d8cf0;
    padding-left: 10px;
    margin-bottom: 15px;
}

textarea, input, select {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    margin: 10px 0;
    font-size: 14px;
}

.btn {
    background: #2d8cf0;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    margin: 5px;
}

.btn:hover {
    background: #1b76d8;
}

.calc-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
    margin-top: 10px;
}

.calc-grid .btn {
    padding: 12px 5px;
}

.footer {
    text-align: center;
    padding: 20px;
    margin-top: 30px;
    color: #666;
    font-size: 14px;
    border-top: 1px solid #eee;
}

canvas {
    margin: 10px auto;
    display: block;
}

@media (max-width: 768px) {
    .two-columns {
        grid-template-columns: 1fr;
    }
}