body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
                 Roboto, "Helvetica Neue", Arial;
    background: linear-gradient(135deg, #f5f7fa, #eef2f7);
    color: #1f2937;
}

/* 主容器 */
.box {
    width: 720px;
    margin: 60px auto;
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    text-align: center;
}

/* 标题 */
h2 {
    margin: 0;
    font-size: 26px;
    font-weight: 700;
}

/* 副标题 */
.subtitle {
    font-size: 14px;
    color: #6b7280;
    margin-top: 6px;
    margin-bottom: 30px;
}

/* 文件输入美化 */
input[type="file"] {
    display: block;
    margin: 20px auto;
    padding: 18px;
    border: 2px dashed #cbd5e1;
    border-radius: 12px;
    width: 90%;
    background: #f9fafb;
    cursor: pointer;
    transition: 0.2s;
}

input[type="file"]:hover {
    border-color: #3b82f6;
    background: #f0f7ff;
}

/* 按钮（SaaS风格） */
button {
    background: #3b82f6;
    color: white;
    border: none;
    padding: 12px 22px;
    border-radius: 10px;
    font-size: 15px;
    cursor: pointer;
    transition: 0.2s;
    margin-top: 10px;
}

button:hover {
    background: #2563eb;
    transform: translateY(-1px);
}

button:active {
    transform: scale(0.98);
}

/* 状态文字 */
#status {
    margin-top: 15px;
    font-size: 14px;
    color: #4b5563;
}

/* 进度条 */
progress {
    width: 100%;
    height: 10px;
    border-radius: 10px;
    overflow: hidden;
    margin-top: 15px;
}

progress::-webkit-progress-bar {
    background-color: #e5e7eb;
    border-radius: 10px;
}

progress::-webkit-progress-value {
    background-color: #3b82f6;
    border-radius: 10px;
}

/* 预览区（数据面板风格） */
pre {
    margin-top: 20px;
    background: #0f172a;
    color: #e2e8f0;
    padding: 16px;
    border-radius: 12px;
    text-align: left;
    font-size: 12px;
    max-height: 220px;
    overflow: auto;
}

/* 小标签 */
h3 {
    margin-top: 30px;
    font-size: 16px;
    color: #374151;
}