/* ==================== 基础变量 ==================== */
:root {
    /* 颜色系统 */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #ec4899;
    --accent: #f59e0b;
    --success: #10b981;
    --danger: #ef4444;
    --info: #3b82f6;

    /* 背景色 */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-card: #1e293b;
    --bg-hover: #334155;

    /* 文字色 */
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --text-dim: #64748b;

    /* 边框 */
    --border: #334155;
    --border-light: #475569;

    /* 渐变 */
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #ec4899 100%);
    --gradient-secondary: linear-gradient(135deg, #3b82f6 0%, #6366f1 100%);
    --gradient-accent: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
    --gradient-dark: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);

    /* 阴影 */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.5);

    /* 圆角 */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* 间距 */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 1rem;
    --space-4: 1.5rem;
    --space-5: 2rem;
    --space-6: 3rem;
    --space-7: 4rem;

    /* 过渡 */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease;
}

/* ==================== 重置样式 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC',
        'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition-fast);
}

a:hover {
    color: var(--primary-light);
}

img {
    max-width: 100%;
    display: block;
}

ul {
    list-style: none;
}

/* ==================== 容器 ==================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ==================== 按钮 ==================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 24px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
    color: white;
}

.btn-outline {
    background: transparent;
    color: var(--text-primary);
    border: 2px solid var(--border-light);
}

.btn-outline:hover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-light);
}

.btn-lg {
    padding: 14px 32px;
    font-size: 16px;
}

.btn-sm {
    padding: 6px 14px;
    font-size: 12px;
}

.btn-block {
    width: 100%;
}

/* ==================== 导航栏 ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(15, 23, 42, 0.95);
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
}

.logo-icon {
    font-size: 28px;
}

.logo-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    gap: 8px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    transition: var(--transition-fast);
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.nav-link.active {
    color: var(--primary-light);
    background: rgba(99, 102, 241, 0.15);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    flex-direction: column;
    gap: 5px;
}

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

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ==================== 英雄区域 ==================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    padding: 100px 20px 60px;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 80% 30%, rgba(236, 72, 153, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 50% 70%, rgba(245, 158, 11, 0.1) 0%, transparent 50%),
                var(--bg-primary);
    z-index: 0;
}

.hero-particles {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
}

.particle {
    position: absolute;
    width: 4px;
    height: 4px;
    background: var(--primary-light);
    border-radius: 50%;
    opacity: 0.4;
    animation: float 20s infinite linear;
}

@keyframes float {
    0% { transform: translateY(100vh) translateX(0); opacity: 0; }
    10% { opacity: 0.4; }
    90% { opacity: 0.4; }
    100% { transform: translateY(-100px) translateX(100px); opacity: 0; }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: var(--radius-full);
    font-size: 13px;
    color: var(--primary-light);
    margin-bottom: 24px;
}

.pulse-dot {
    width: 8px;
    height: 8px;
    background: var(--success);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.5); opacity: 0.5; }
}

.hero-title {
    font-size: clamp(36px, 6vw, 64px);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: inline-block;
}

.hero-subtitle {
    font-size: clamp(15px, 2vw, 18px);
    color: var(--text-secondary);
    margin-bottom: 40px;
    line-height: 1.8;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 60px;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    padding: 30px;
    background: rgba(30, 41, 59, 0.5);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: clamp(24px, 4vw, 36px);
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 4px;
}

.stat-label {
    font-size: 13px;
    color: var(--text-muted);
}

/* ==================== 广告位 ==================== */
.ad-banner {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    padding: 12px 0;
}

.ad-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.ad-content {
    display: flex;
    align-items: center;
    gap: 12px;
}

.ad-label {
    padding: 2px 8px;
    background: var(--bg-tertiary);
    color: var(--text-muted);
    font-size: 11px;
    border-radius: var(--radius-sm);
}

.ad-text {
    color: var(--text-secondary);
    font-size: 14px;
}

.ad-close {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 20px;
    cursor: pointer;
    padding: 0 8px;
}

.ad-section {
    padding: 40px 0;
}

.ad-slot {
    background: var(--bg-secondary);
    border: 2px dashed var(--border-light);
    border-radius: var(--radius-lg);
    padding: 30px;
    text-align: center;
}

.ad-slot .ad-label {
    display: inline-block;
    margin-bottom: 12px;
}

.ad-placeholder {
    color: var(--text-muted);
    font-size: 15px;
}

/* ==================== 区块通用 ==================== */
section {
    padding: 80px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-title {
    font-size: clamp(28px, 4vw, 40px);
    font-weight: 700;
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 16px;
    color: var(--text-muted);
}

/* ==================== 资源卡片 ==================== */
.resource-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.resource-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 30px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.resource-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

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

.resource-card:hover::before {
    transform: scaleX(1);
}

.resource-icon {
    font-size: 48px;
    margin-bottom: 20px;
    display: inline-block;
}

.cloud-icon { filter: drop-shadow(0 0 10px rgba(99, 102, 241, 0.5)); }
.learning-icon { filter: drop-shadow(0 0 10px rgba(236, 72, 153, 0.5)); }
.template-icon { filter: drop-shadow(0 0 10px rgba(245, 158, 11, 0.5)); }
.game-icon { filter: drop-shadow(0 0 10px rgba(16, 185, 129, 0.5)); }

.resource-title {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 12px;
}

.resource-desc {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.6;
    margin-bottom: 16px;
}

.resource-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 20px;
}

.tag {
    padding: 4px 10px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    font-size: 12px;
    color: var(--text-secondary);
}

.resource-footer {
    border-top: 1px solid var(--border);
    padding-top: 16px;
}

.resource-link {
    color: var(--primary-light);
    font-size: 14px;
    font-weight: 600;
}

/* ==================== 特色 ==================== */
.features {
    background: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.feature-item {
    text-align: center;
    padding: 30px;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: var(--transition);
}

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

.feature-icon {
    font-size: 40px;
    margin-bottom: 16px;
}

.feature-item h3 {
    font-size: 20px;
    margin-bottom: 10px;
}

.feature-item p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* ==================== 热门推荐 ==================== */
.popular-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.popular-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition);
    position: relative;
}

.popular-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.popular-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    padding: 4px 10px;
    border-radius: var(--radius-full);
    font-size: 11px;
    font-weight: 700;
    color: white;
    z-index: 1;
}

.popular-badge.hot { background: var(--danger); }
.popular-badge.new { background: var(--success); }
.popular-badge.rec { background: var(--accent); }

.popular-img {
    height: 160px;
    background: var(--gradient-dark);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 60px;
}

.popular-content {
    padding: 24px;
}

.popular-content h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.popular-desc {
    color: var(--text-secondary);
    font-size: 13px;
    margin-bottom: 16px;
    line-height: 1.5;
}

.popular-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.price {
    font-size: 20px;
    font-weight: 700;
    color: var(--accent);
}

.original-price {
    color: var(--text-dim);
    text-decoration: line-through;
    font-size: 14px;
}

.students {
    color: var(--text-muted);
    font-size: 13px;
}

/* ==================== 评价 ==================== */
.testimonials {
    background: var(--bg-secondary);
}

.testimonial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.testimonial-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 30px;
    transition: var(--transition);
}

.testimonial-card:hover {
    border-color: var(--primary);
}

.testimonial-stars {
    color: var(--accent);
    font-size: 18px;
    margin-bottom: 16px;
    letter-spacing: 2px;
}

.testimonial-text {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
    margin-bottom: 20px;
    font-style: italic;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 12px;
}

.author-avatar {
    width: 48px;
    height: 48px;
    background: var(--bg-tertiary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
}

.author-name {
    font-weight: 600;
}

.author-title {
    font-size: 13px;
    color: var(--text-muted);
}

/* ==================== CTA ==================== */
.cta {
    background: var(--gradient-primary);
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.cta::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 50%);
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.cta-content {
    position: relative;
    z-index: 1;
}

.cta-title {
    font-size: clamp(28px, 4vw, 40px);
    font-weight: 700;
    margin-bottom: 16px;
    color: white;
}

.cta-subtitle {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 32px;
}

.cta-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

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

.cta .btn-outline {
    border-color: white;
    color: white;
}

.cta .btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
}

/* ==================== 联系 ==================== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 40px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

.contact-icon {
    width: 48px;
    height: 48px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 16px;
    margin-bottom: 4px;
}

.contact-item p {
    color: var(--text-secondary);
    font-size: 14px;
}

.contact-form {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 30px;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-group textarea {
    resize: vertical;
}

/* ==================== 页脚 ==================== */
.footer {
    background: var(--bg-secondary);
    padding: 60px 0 30px;
    border-top: 1px solid var(--border);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 2fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 16px;
}

.footer-desc {
    color: var(--text-muted);
    font-size: 14px;
    margin-bottom: 20px;
}

.social-links {
    display: flex;
    gap: 12px;
}

.social-link {
    width: 36px;
    height: 36px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    transition: var(--transition-fast);
}

.social-link:hover {
    background: var(--primary);
    border-color: var(--primary);
    transform: translateY(-2px);
}

.footer-col h4 {
    font-size: 16px;
    margin-bottom: 16px;
}

.footer-col ul li {
    margin-bottom: 8px;
}

.footer-col ul li a {
    color: var(--text-muted);
    font-size: 14px;
}

.footer-col ul li a:hover {
    color: var(--primary-light);
}

.subscribe-form {
    display: flex;
    gap: 8px;
    margin-top: 12px;
}

.subscribe-form input {
    flex: 1;
    padding: 8px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 13px;
}

.subscribe-form input:focus {
    outline: none;
    border-color: var(--primary);
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 13px;
}

/* ==================== 返回顶部 ==================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 24px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
    box-shadow: var(--shadow-lg);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-glow);
}

/* ==================== 响应式 ==================== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-secondary);
        flex-direction: column;
        padding: 20px;
        gap: 4px;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
        border-bottom: 1px solid var(--border);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-toggle {
        display: flex;
    }

    .hero {
        padding-top: 120px;
    }

    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
        padding: 20px;
    }

    .hero-actions {
        flex-direction: column;
        width: 100%;
    }

    .hero-actions .btn {
        width: 100%;
    }

    section {
        padding: 60px 0;
    }

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

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .cta-actions {
        flex-direction: column;
        width: 100%;
    }

    .cta-actions .btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .hero-stats {
        grid-template-columns: 1fr 1fr;
    }

    .resource-card,
    .feature-item,
    .testimonial-card {
        padding: 20px;
    }
}

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

.fade-in {
    animation: fadeInUp 0.6s ease forwards;
}

/* 滚动显示动画 */
.scroll-reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.scroll-reveal.visible {
    opacity: 1;
    transform: translateY(0);
}