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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    display: flex;
    min-height: 100vh;
    background-color: #f5f7fa;
    color: #333;
}

/* ========== 左侧导航 ========== */
.sidebar {
    width: 250px;
    background-color: #1a1a2e;
    color: #fff;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    overflow-y: auto;
    padding: 20px 0;
    z-index: 100;
}

.sidebar-header {
    padding: 0 20px 20px;
    border-bottom: 1px solid #333;
    margin-bottom: 10px;
}

.sidebar-header h2 {
    font-size: 18px;
    font-weight: 500;
}

.nav-list {
    list-style: none;
    padding: 0;
}

.nav-link {
    display: block;
    padding: 12px 20px;
    color: #aaa;
    text-decoration: none;
    font-size: 14px;
    transition: all 0.2s;
}

.nav-link:hover {
    color: #fff;
    background: rgba(255,255,255,0.05);
}

.nav-link.active {
    color: #fff;
    background: #16213e;
    border-left: 3px solid #0f9d58;
    font-weight: 500;
}

/* ========== 右侧内容区 ========== */
.content {
    margin-left: 250px;
    padding: 40px;
    width: 100%;
    max-width: 960px;
}

section {
    margin-bottom: 60px;
}

section h2 {
    font-size: 24px;
    margin-bottom: 20px;
    color: #1a1a2e;
    border-bottom: 2px solid #0f9d58;
    padding-bottom: 8px;
}

section h3 {
    font-size: 18px;
    margin: 20px 0 10px;
    color: #333;
}

p {
    font-size: 15px;
    line-height: 1.8;
    color: #555;
    margin-bottom: 15px;
}

.step-box {
    background: #fff;
    padding: 20px;
    border-radius: 8px;
    border-left: 4px solid #0f9d58;
    box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    margin-bottom: 20px;
}

.step-box p {
    margin-bottom: 8px;
}

.warning-box {
    background: #fff3e0;
    border-left: 4px solid #ff8c00;
    padding: 16px;
    border-radius: 8px;
    margin-top: 20px;
    color: #e65100;
    font-size: 14px;
    line-height: 1.7;
}

.faq-item {
    margin-bottom: 25px;
}

.faq-item h3 {
    font-size: 17px;
    color: #1a1a2e;
    margin-bottom: 6px;
}

.content-footer {
    margin-top: 40px;
    text-align: center;
    color: #999;
    font-size: 13px;
}

img, video {
    max-width: 100%;
    border-radius: 6px;
    margin: 10px 0;
    border: 1px solid #e0e0e0;
}

/* ========== 切换显示控制 ========== */
.section-content {
    display: none;
}
.section-content.active {
    display: block;
}

/* ========== 移动端适配 ========== */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
        padding: 10px;
    }
    .content {
        margin-left: 0;
        padding: 20px;
    }
    .nav-link {
        display: inline-block;
        padding: 8px 12px;
    }
}