/* ===== 全局样式 ===== */
:root {
    --primary-color: #00f2ff;
    --secondary-color: #7b2cbf;
    --accent-color: #ff006e;
    --success-color: #00ff88;
    --bg-dark: #0a0e27;
    --bg-darker: #050818;
    --bg-card: #151937;
    --text-primary: #ffffff;
    --text-secondary: #a8b2d1;
    --text-muted: #6b7280;
    --border-color: rgba(255, 255, 255, 0.1);
    --shadow-sm: 0 2px 8px rgba(0, 242, 255, 0.1);
    --shadow-md: 0 8px 24px rgba(0, 242, 255, 0.15);
    --shadow-lg: 0 16px 48px rgba(0, 242, 255, 0.2);
    --gradient-primary: linear-gradient(135deg, #00f2ff 0%, #7b2cbf 100%);
    --gradient-secondary: linear-gradient(135deg, #ff006e 0%, #7b2cbf 100%);
    --gradient-accent: linear-gradient(135deg, #00ff88 0%, #00f2ff 100%);
    --bg-dark-soft: rgba(10, 14, 39, 0.85);
    --bg-darker-soft: rgba(5, 8, 24, 0.95);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
    min-height: 100vh;
}

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

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 14, 39, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background: rgba(10, 14, 39, 0.95);
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 800;
    z-index: 1001;
}

.logo-icon {
    position: relative;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 10px;
    box-shadow: 0 4px 16px rgba(0, 242, 255, 0.3);
}

.logo-icon i {
    font-size: 20px;
    color: white;
    animation: rotate 20s linear infinite;
}

.logo-pulse {
    position: absolute;
    width: 100%;
    height: 100%;
    border-radius: 10px;
    background: var(--gradient-primary);
    opacity: 0.5;
    animation: pulse 2s ease-in-out infinite;
}

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

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.2); opacity: 0; }
}

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

.logo-suffix {
    font-size: 14px;
    vertical-align: super;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 15px;
    transition: all 0.3s ease;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width 0.3s ease;
}

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-cta .btn-nav-download {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 16px rgba(0, 242, 255, 0.3);
}

.btn-nav-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.4);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 6px;
    cursor: pointer;
    z-index: 1001;
}

.hamburger span {
    width: 28px;
    height: 3px;
    background: var(--primary-color);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
}

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

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(8px, -8px);
}

/* ===== 英雄区 ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding-top: 80px;
}

.site-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
    background: radial-gradient(circle at 20% 20%, rgba(0, 242, 255, 0.08), transparent 60%);
}

.grid-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(rgba(0, 242, 255, 0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 242, 255, 0.05) 1px, transparent 1px);
    background-size: 50px 50px;
    opacity: 0.3;
}

#particleCanvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.6;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, #00f2ff 0%, transparent 70%);
    top: 10%;
    left: 10%;
    animation-delay: 0s;
}

.orb-2 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, #7b2cbf 0%, transparent 70%);
    top: 40%;
    right: 10%;
    animation-delay: 5s;
}

.orb-3 {
    width: 350px;
    height: 350px;
    background: radial-gradient(circle, #ff006e 0%, transparent 70%);
    bottom: 20%;
    left: 50%;
    animation-delay: 10s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(50px, -50px) scale(1.1); }
    66% { transform: translate(-50px, 50px) scale(0.9); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
    padding: 0 24px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: rgba(0, 242, 255, 0.1);
    border: 1px solid rgba(0, 242, 255, 0.3);
    border-radius: 50px;
    color: var(--primary-color);
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 32px;
}

.hero-title {
    font-size: clamp(48px, 8vw, 72px);
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
}

.title-line {
    display: block;
}

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

.hero-description {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 48px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 64px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 16px 32px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 32px rgba(0, 242, 255, 0.4);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 48px;
    flex-wrap: wrap;
}

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

.stat-number {
    font-size: 36px;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 4px;
}

.stat-divider {
    width: 1px;
    height: 60px;
    background: var(--border-color);
}

.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 12px;
    animation: bounce 2s ease-in-out infinite;
}

.scroll-line {
    width: 2px;
    height: 40px;
    background: linear-gradient(to bottom, transparent, var(--primary-color));
}

@keyframes bounce {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(10px); }
}

/* ===== 通用区块样式 ===== */
section {
    padding: 120px 0;
    position: relative;
}

.section-header {
    text-align: center;
}

.section-tag {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    background: rgba(0, 242, 255, 0.1);
    border: 1px solid rgba(0, 242, 255, 0.3);
    border-radius: 50px;
    color: var(--primary-color);
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 16px;
}

.section-title {
    font-size: clamp(36px, 5vw, 48px);
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}

.section-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ===== 功能特色 ===== */
.features,
.platforms,
.download,
.tutorial,
.contact,
.footer {
    -webkit-backdrop-filter: blur(18px);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.feature-card {
    position: relative;
    padding: 40px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    transition: all 0.3s ease;
    cursor: pointer;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 0;
}

.feature-card:hover::before {
    opacity: 0.05;
}

.feature-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
}

.feature-card > * {
    position: relative;
    z-index: 1;
}

.feature-icon-wrapper {
    position: relative;
    width: 80px;
    height: 80px;
    margin-bottom: 24px;
}

.feature-icon {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 16px;
    font-size: 32px;
    color: white;
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
}

.feature-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 16px;
    filter: blur(20px);
    opacity: 0.5;
    z-index: -1;
}

.feature-card h3 {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 20px;
}

.feature-link {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 14px;
    opacity: 0;
    transform: translateX(-10px);
    transition: all 0.3s ease;
}

.feature-card:hover .feature-link {
    opacity: 1;
    transform: translateX(0);
}

/* ===== 支持平台 ===== */

.platforms-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 24px;
}

.platform-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    padding: 32px 24px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.platform-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

.platform-logo {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    font-size: 28px;
    color: white;
    transition: all 0.3s ease;
}

.platform-card:hover .platform-logo {
    transform: scale(1.1);
}

.platform-logo.sohu { background: linear-gradient(135deg, #ff4757 0%, #ff6348 100%); }
.platform-logo.baijia { background: linear-gradient(135deg, #1e90ff 0%, #00bfff 100%); }
.platform-logo.toutiao { background: linear-gradient(135deg, #ff4444 0%, #ff6666 100%); }
.platform-logo.zhihu { background: linear-gradient(135deg, #0084ff 0%, #0099ff 100%); }
.platform-logo.xiaohongshu { background: linear-gradient(135deg, #ff2442 0%, #ff4466 100%); }
.platform-logo.bilibili { background: linear-gradient(135deg, #00a1d6 0%, #00c0ff 100%); }
.platform-logo.csdn { background: linear-gradient(135deg, #fc5531 0%, #ff6644 100%); }
.platform-logo.jianshu { background: linear-gradient(135deg, #ea6f5a 0%, #ff8866 100%); }
.platform-logo.douyin { background: linear-gradient(135deg, #fe2c55 0%, #ff4477 100%); }
.platform-logo.wechat { background: linear-gradient(135deg, #07c160 0%, #00dd77 100%); }

.platform-name {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 14px;
}

/* ===== 下载区域 ===== */

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 32px;
    margin-bottom: 64px;
}

.download-card {
    position: relative;
    padding: 48px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    transition: all 0.3s ease;
}

.download-card.primary {
    border-color: rgba(255, 100, 100, 0.3);
}

.download-card.featured {
    border-color: var(--primary-color);
    box-shadow: 0 0 40px rgba(0, 242, 255, 0.2);
}

.download-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
}

.card-icon {
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 16px;
    font-size: 28px;
    color: white;
}

.download-card.primary .card-icon {
    background: linear-gradient(135deg, #ff4444 0%, #ff6666 100%);
}

.card-badge {
    padding: 6px 16px;
    background: rgba(0, 242, 255, 0.1);
    border: 1px solid var(--primary-color);
    border-radius: 50px;
    color: var(--primary-color);
    font-size: 12px;
    font-weight: 600;
}

.card-badge.important {
    background: rgba(255, 68, 68, 0.1);
    border-color: #ff4444;
    color: #ff6666;
}

.download-card h3 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 16px;
}

.download-card > p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 24px;
}

.card-features {
    margin-bottom: 32px;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 0;
    color: var(--text-secondary);
}

.feature-item i {
    color: var(--success-color);
    font-size: 16px;
}

.btn-download {
    width: 100%;
    justify-content: center;
    font-size: 16px;
    padding: 16px;
}

.download-card.featured .btn-download {
    background: var(--gradient-primary);
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
}

.download-card.primary .btn-download {
    background: linear-gradient(135deg, #ff4444 0%, #ff6666 100%);
    box-shadow: 0 8px 24px rgba(255, 68, 68, 0.3);
}

.download-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 16px;
    font-size: 13px;
    color: var(--text-muted);
}

.download-meta i {
    margin-right: 4px;
}

.system-requirements {
    padding: 40px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
}

.system-requirements h3 {
    font-size: 20px;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.requirements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
}

.requirement-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 15px;
    color: var(--text-secondary);
}

.requirement-item i {
    font-size: 24px;
    color: var(--primary-color);
}

/* ===== 使用教程 ===== */

.tutorial-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: start;
}

.video-wrapper {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 24px;
    overflow: hidden;
}

.video-placeholder {
    padding: 80px 48px;
    text-align: center;
}

.video-placeholder i {
    font-size: 64px;
    color: var(--primary-color);
    margin-bottom: 24px;
}

.video-placeholder h3 {
    font-size: 24px;
    margin-bottom: 16px;
}

.video-placeholder p {
    color: var(--text-secondary);
    margin-bottom: 32px;
}

.btn-video {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    padding: 16px 32px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
}

.btn-video:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 32px rgba(0, 242, 255, 0.4);
}

.tutorial-steps h3 {
    font-size: 28px;
    margin-bottom: 32px;
}

.step-list {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.step-item {
    display: flex;
    gap: 24px;
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    transition: all 0.3s ease;
}

.step-item:hover {
    border-color: var(--primary-color);
    transform: translateX(8px);
}

.step-number {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 12px;
    font-size: 18px;
    font-weight: 700;
    color: white;
}

.step-content h4 {
    font-size: 18px;
    margin-bottom: 8px;
}

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

/* ===== 联系我们 ===== */

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.contact-card {
    padding: 48px 32px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    text-align: center;
    transition: all 0.3s ease;
}

.contact-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: 50%;
    font-size: 32px;
    color: white;
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
}

.contact-card h3 {
    font-size: 22px;
    margin-bottom: 16px;
}

.contact-card a,
.wechat-id {
    display: inline-block;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    transition: all 0.3s ease;
}

.contact-card a:hover {
    text-decoration: underline;
}

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

/* ===== 页脚 ===== */
.footer {
    border-top: 1px solid var(--border-color);
    padding: 80px 0 32px;
}

.footer-top {
    display: grid;
    grid-template-columns: 2fr 3fr;
    gap: 64px;
    margin-bottom: 48px;
}

.footer-brand {
    max-width: 400px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 800;
    margin-bottom: 20px;
}

.footer-brand p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 24px;
}

.social-links {
    display: flex;
    gap: 16px;
}

.social-links a {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-secondary);
    font-size: 18px;
    transition: all 0.3s ease;
}

.social-links a:hover {
    background: var(--gradient-primary);
    border-color: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 48px;
}

.footer-column h4 {
    font-size: 16px;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.footer-column ul {
    list-style: none;
}

.footer-column li {
    margin-bottom: 12px;
}

.footer-column a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.3s ease;
}

.footer-column a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 32px;
    border-top: 1px solid var(--border-color);
    flex-wrap: wrap;
    gap: 16px;
}

.copyright p {
    color: var(--text-muted);
    font-size: 14px;
}

.footer-meta {
    display: flex;
    gap: 16px;
    color: var(--text-muted);
    font-size: 14px;
}

/* ===== 返回顶部 ===== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 20px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 8px 24px rgba(0, 242, 255, 0.3);
    z-index: 999;
}

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

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 32px rgba(0, 242, 255, 0.4);
}

/* ===== 响应式设计 ===== */
@media (max-width: 1024px) {
    .tutorial-content {
        grid-template-columns: 1fr;
    }
    
    .footer-top {
        grid-template-columns: 1fr;
        gap: 48px;
    }
    
    .download-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 80px);
        background: rgba(10, 14, 39, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 32px;
        transition: left 0.3s ease;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-cta {
        display: none;
    }
    
    .hamburger {
        display: flex;
    }
    
    .hero-stats {
        gap: 24px;
    }
    
    .stat-divider {
        display: none;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .platforms-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
        gap: 16px;
    }
    
    .download-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 32px;
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
    
    section {
        padding: 80px 0;
    }
    
    .section-header {
        margin-bottom: 48px;
    }
}

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-buttons .btn {
        width: 100%;
        justify-content: center;
    }
    
    .download-card {
        padding: 32px 24px;
    }
    
    .back-to-top {
        bottom: 16px;
        right: 16px;
        width: 44px;
        height: 44px;
    }
}

/* ===== AOS 动画库样式 ===== */
[data-aos] {
    opacity: 0;
    transition-property: opacity, transform;
}

[data-aos].aos-animate {
    opacity: 1;
}

[data-aos="fade-up"] {
    transform: translateY(30px);
}

[data-aos="fade-up"].aos-animate {
    transform: translateY(0);
}

[data-aos="fade-down"] {
    transform: translateY(-30px);
}

[data-aos="fade-down"].aos-animate {
    transform: translateY(0);
}

[data-aos="fade-left"] {
    transform: translateX(-30px);
}

[data-aos="fade-left"].aos-animate {
    transform: translateX(0);
}

[data-aos="fade-right"] {
    transform: translateX(30px);
}

[data-aos="fade-right"].aos-animate {
    transform: translateX(0);
}

[data-aos="zoom-in"] {
    transform: scale(0.9);
}

[data-aos="zoom-in"].aos-animate {
    transform: scale(1);
}