/* assets/css/style.css */
:root {
    --primary-color: #2ecc71; /* 绿色主调 */
    --secondary-color: #27ae60;
    --text-color: #333;
    --bg-light: #f4f4f4;
    --white: #fff;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-light);
}

/* --- 导航栏 (Flexbox) --- */
header {
    background: var(--white);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-list {
    display: flex;
    list-style: none;
}

.nav-list li {
    margin-left: 20px;
}

.nav-list a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
}

.nav-list a:hover, .nav-list a.active {
    color: var(--primary-color);
}

/* 移动端菜单按钮 */
.menu-toggle {
    display: none;
    cursor: pointer;
    flex-direction: column;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    margin: 3px 0;
}

/* --- 通用布局 --- */
main {
    min-height: 80vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

section {
    padding: 3rem 0;
}

h1, h2 {
    text-align: center;
    margin-bottom: 2rem;
}

/* --- 按钮样式 --- */
.btn {
    display: inline-block;
    padding: 10px 20px;
    background: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: var(--transition);
}

.btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

/* --- Footer --- */
footer {
    background: #333;
    color: var(--white);
    text-align: center;
    padding: 1.5rem 0;
    margin-top: auto;
}

/* --- 动画关键帧 (CSS Animation) --- */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeInUp 0.8s ease-out forwards;
}

/* --- 响应式设计 (Media Queries) --- */
@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    .nav-list {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        text-align: center;
        box-shadow: 0 5px 5px rgba(0,0,0,0.1);
    }
    
    .nav-list.active {
        display: flex;
    }
    
    .nav-list li {
        margin: 15px 0;
    }
}