:root {
    --primary-color: #2c5282;
    --secondary-color: #3182ce;
    --light-color: #f7fafc;
    --dark-color: #2d3748;
    --transition-speed: 0.3s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: #333;
    overflow-x: hidden;
}

/* 导航栏 */
.navbar {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.nav-link {
    font-weight: 500;
    color: var(--dark-color);
    transition: color var(--transition-speed);
    padding: 1rem 1.5rem;
}

.nav-link:hover, .nav-link.active {
    color: var(--secondary-color);
}

.dropdown-menu {
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.dropdown-item {
    font-weight: 400;
    padding: 0.5rem 1.5rem;
}

.dropdown-item:hover {
    background-color: rgba(44, 82, 130, 0.1);
}

/* 使用教程内容页 */
.dh {
    width: 18%;
    margin-left: 5%;
}

.tutorial-content-wrapper {
    padding: 2rem 0;
}

.left-sidebar {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    padding: 2rem;
    position: sticky;
    top: 100px;
    height: fit-content;
}

.left-sidebar h3 {
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    font-size: 1.25rem;
}

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

.tutorial-nav li {
    margin-bottom: 0.8rem;
}

.tutorial-nav a {
    color: var(--dark-color);
    text-decoration: none;
    transition: color var(--transition-speed);
    font-weight: 500;
    display: block;
    padding: 0.5rem;
    border-radius: 8px;
    font-size: 1rem;
}

.tutorial-nav a:hover, .tutorial-nav a.active {
    color: var(--secondary-color);
    background-color: rgba(44, 82, 130, 0.1);
}

.tutorial-content {
    padding: 2rem;
    background-color: transparent;
    border-radius: 0;
    box-shadow: none;
}

.tutorial-content h1 {
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    font-size: 1.75rem;
}

.tutorial-content h2 {
    font-weight: 600;
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: var(--secondary-color);
    font-size: 1.5rem;
}

.tutorial-content h3 {
    font-weight: 500;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--dark-color);
    font-size: 1.25rem;
}

.tutorial-content p {
    line-height: 1.8;
    margin-bottom: 1.5rem;
    font-size: 1rem;
}

/* 版权信息栏 */
.footer {
    background-color: var(--dark-color);
    color: white;
    padding: 3rem 0;
    margin-top: 3rem;
}

.footer-logo {
    margin-top: 1rem;
}

.footer h5 {
    font-weight: 600;
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.footer-links {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #cbd5e0;
    text-decoration: none;
    transition: color var(--transition-speed);
    font-size: 0.95rem;
}

.footer-links a:hover {
    color: white;
}

.copyright {
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.copyright a {
    color: #cbd5e0;
    text-decoration: none;
}

.copyright a:hover {
    text-decoration: underline;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .left-sidebar {
        position: static;
        margin-bottom: 2rem;
    }
}