/* ===== 基础样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #2c6fbb;
    --primary-dark: #1e4f8a;
    --primary-light: #e8f0fa;
    --accent: #f0a030;
    --text: #333;
    --text-light: #666;
    --bg: #fff;
    --bg-light: #f8f9fc;
    --border: #e8e8e8;
    --shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
    --radius: 12px;
    --transition: 0.3s ease;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text);
    line-height: 1.8;
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}

.navbar.scrolled {
    border-bottom-color: var(--border);
    box-shadow: 0 1px 10px rgba(0, 0, 0, 0.06);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--primary);
    font-weight: 700;
    font-size: 1.2rem;
}

.logo-icon {
    font-size: 1.6rem;
    color: var(--accent);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 8px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text);
    font-size: 0.95rem;
    padding: 8px 16px;
    border-radius: 8px;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--primary);
    background: var(--primary-light);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: var(--transition);
}

/* ===== 首页横幅 ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    z-index: 0;
}

.hero-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.hero-content {
    position: relative;
    z-index: 1;
    color: #fff;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    letter-spacing: 4px;
    margin-bottom: 16px;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    margin-bottom: 12px;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-desc {
    font-size: 1.05rem;
    opacity: 0.8;
    margin-bottom: 40px;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.hero .btn {
    animation: fadeInUp 0.8s ease 0.6s both;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===== 按钮 ===== */
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-family: inherit;
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 4px 15px rgba(240, 160, 48, 0.4);
}

.btn-primary:hover {
    background: #e09020;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(240, 160, 48, 0.5);
}

.btn-full {
    width: 100%;
    text-align: center;
}

/* ===== 通用区块 ===== */
.section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-header h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 12px;
}

.section-desc {
    font-size: 1.05rem;
    color: var(--text-light);
}

/* ===== 关于我们 ===== */
.about {
    background: var(--bg);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-text p {
    margin-bottom: 20px;
    color: var(--text-light);
    font-size: 0.98rem;
}

.about-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.stat-item {
    background: var(--bg-light);
    border-radius: var(--radius);
    padding: 32px 24px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border);
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary);
}

.stat-number {
    font-size: 2.4rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.2;
}

.stat-number span {
    font-size: 1.4rem;
}

.stat-label {
    margin-top: 8px;
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ===== 课程服务 ===== */
.services {
    background: var(--bg-light);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 28px;
}

.service-card {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 40px 32px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--border);
}

.service-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary);
}

.service-icon {
    font-size: 2.8rem;
    margin-bottom: 20px;
}

.service-card h3 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text);
}

.service-card p {
    font-size: 0.9rem;
    color: var(--text-light);
    line-height: 1.7;
}

/* ===== 核心优势 ===== */
.advantages {
    background: var(--bg);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 28px;
}

.advantage-item {
    text-align: center;
    padding: 40px 24px;
    border-radius: var(--radius);
    transition: var(--transition);
}

.advantage-item:hover {
    background: var(--bg-light);
}

.advantage-icon {
    font-size: 2.8rem;
    margin-bottom: 20px;
}

.advantage-item h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text);
}

.advantage-item p {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ===== 联系我们 ===== */
.contact {
    background: var(--bg-light);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.info-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 24px;
    background: var(--bg);
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.info-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.info-item h4 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.info-item p,
.info-item a {
    font-size: 0.9rem;
    color: var(--text-light);
    text-decoration: none;
}

.info-item a:hover {
    color: var(--primary);
}

.contact-form {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 40px;
    border: 1px solid var(--border);
}

.contact-form h3 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 28px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 14px 18px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 0.95rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--bg-light);
    outline: none;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-light);
    background: var(--bg);
}

.form-group textarea {
    resize: vertical;
}

.form-group select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
}

/* ===== 页脚 ===== */
.footer {
    background: #1a1a2e;
    color: rgba(255, 255, 255, 0.8);
    padding: 60px 0 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.footer-brand .logo-icon {
    font-size: 1.4rem;
}

.footer-brand .logo-text {
    font-size: 1.1rem;
    font-weight: 700;
    color: #fff;
}

.footer-brand p {
    font-size: 0.85rem;
    opacity: 0.6;
    margin-top: 4px;
}

.footer-links {
    display: flex;
    gap: 24px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--accent);
}

.footer-bottom {
    text-align: center;
    padding: 24px 0;
    font-size: 0.85rem;
    opacity: 0.5;
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .advantages-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        background: #fff;
        flex-direction: column;
        padding: 16px 24px;
        border-bottom: 1px solid var(--border);
        box-shadow: var(--shadow);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        padding: 12px 16px;
    }

    .hero h1 {
        font-size: 2rem;
        letter-spacing: 2px;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .section {
        padding: 70px 0;
    }

    .section-header h2 {
        font-size: 1.6rem;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .advantages-grid {
        grid-template-columns: 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .footer-content {
        flex-direction: column;
        gap: 24px;
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero h1 {
        font-size: 1.6rem;
    }

    .about-stats {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .stat-item {
        padding: 24px 16px;
    }

    .stat-number {
        font-size: 2rem;
    }

    .contact-form {
        padding: 28px 20px;
    }
}