/* 全局样式 */
:root {
    --primary-color: #0056b3; /* 深蓝色 */
    --secondary-color: #ff6b00; /* 橙色 */
    --text-color: #333;
    --light-gray: #f4f4f4;
    --white: #ffffff;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--white);
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 60px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 40px;
    color: var(--primary-color);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background: var(--secondary-color);
    margin: 10px auto 0;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 5px;
    font-weight: bold;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--secondary-color);
    color: var(--white);
}

.btn-primary:hover {
    background-color: #e65c00;
}

.btn-outline {
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    margin-top: 10px;
}

.btn-outline:hover {
    background-color: var(--primary-color);
    color: var(--white);
}

.bg-light {
    background-color: var(--light-gray);
}

/* 导航栏 */
.navbar {
    background-color: var(--white);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 15px 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
}

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

.nav-links a {
    font-weight: 500;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--secondary-color);
}

.menu-toggle {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero Section */
.hero {
    background-image: linear-gradient(rgba(0, 86, 179, 0.8), rgba(0, 86, 179, 0.8)), url('https://images.unsplash.com/photo-1517649763962-0c623066013b?ixlib=rb-1.2.1&auto=format&fit=crop&w=1350&q=80'); /* 替换为实际图片URL或保持占位 */
    background-size: cover;
    background-position: center;
    height: 80vh;
    display: flex;
    align-items: center;
    text-align: center;
    color: var(--white);
    position: relative;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
}

.hero-content p {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.hero-content .highlight {
    font-size: 1.2rem;
    color: #ffd700;
    margin-bottom: 30px;
    font-weight: bold;
}

/* 课程介绍 */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.course-card {
    background: var(--white);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    text-align: center;
    transition: var(--transition);
}

.course-card:hover {
    transform: translateY(-10px);
}

.course-card .icon {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.course-card h3 {
    margin-bottom: 15px;
    font-size: 1.5rem;
}

/* 关于我们/优势 */
.features {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    text-align: center;
}

.feature-item {
    flex-basis: 30%;
    margin-bottom: 30px;
    padding: 20px;
}

.feature-item i {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 20px;
}

.feature-item h4 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

/* 联系我们 */
.contact-section {
    background-color: var(--primary-color);
    color: var(--white);
}

.contact-section .section-title {
    color: var(--white);
}

.contact-section .section-title::after {
    background: var(--white);
}

.contact-info {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 50px;
    text-align: center;
}

.contact-item {
    background: rgba(255, 255, 255, 0.1);
    padding: 30px;
    border-radius: 10px;
    min-width: 280px;
}

.contact-item i {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.contact-item h3 {
    margin-bottom: 15px;
}

.contact-item p {
    font-size: 1.2rem;
}

/* 页脚 */
footer {
    background: #222;
    color: var(--white);
    text-align: center;
    padding: 20px 0;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-links {
        position: absolute;
        right: 0;
        top: 60px;
        background: var(--white);
        flex-direction: column;
        width: 100%;
        text-align: center;
        transform: translateY(-150%);
        transition: var(--transition);
        box-shadow: 0 5px 5px rgba(0,0,0,0.1);
    }

    .nav-links.active {
        transform: translateY(0);
    }

    .nav-links li {
        margin: 20px 0;
    }

    .menu-toggle {
        display: block;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

    .hero-content p {
        font-size: 1.2rem;
    }

    .features {
        flex-direction: column;
    }
}