/* ========================================
   1. CSS变量 & 重置
   ======================================== */
:root {
    --primary: #667eea;
    --primary-dark: #5a6fd6;
    --secondary: #764ba2;
    --success: #4ade80;
    --danger: #f5576c;
    --warning: #fbbf24;
    --dark: #1a1a2e;
    --gray: #666;
    --light-gray: #999;
    --bg: #f8f9fa;
    --white: #ffffff;
    --shadow: 0 4px 30px rgba(0,0,0,0.08);
    --radius: 16px;
    --transition: all 0.3s ease;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, 'Segoe UI', Roboto, 'PingFang SC', 'Microsoft YaHei', sans-serif;
    color: var(--dark);
    line-height: 1.6;
    overflow-x: hidden;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; }

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

/* ========================================
   2. 按钮
   ======================================== */
.btn {
    display: inline-block;
    padding: 10px 28px;
    border-radius: 30px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    border: 2px solid transparent;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--white);
    border-color: transparent;
}
.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(102, 126, 234, 0.4);
}

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

.btn-large { padding: 14px 40px; font-size: 16px; }
.w-full { width: 100%; }

/* ========================================
   3. 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 rgba(0,0,0,0.05);
    padding: 16px 0;
    transition: var(--transition);
}

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

.nav-brand a {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
}
.brand-icon { font-size: 28px; }
.brand-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-menu {
    display: flex;
    gap: 32px;
    align-items: center;
}
.nav-menu a {
    font-size: 15px;
    color: var(--gray);
    transition: var(--transition);
    position: relative;
}
.nav-menu a:hover,
.nav-menu a.active {
    color: var(--primary);
}
.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
}

.nav-actions { display: flex; gap: 12px; }
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
}
.nav-toggle span {
    width: 28px;
    height: 3px;
    background: var(--dark);
    border-radius: 3px;
    transition: var(--transition);
}

/* ========================================
   4. 首页横幅
   ======================================== */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf1 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

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

.hero-badge {
    display: inline-block;
    padding: 6px 18px;
    background: rgba(102, 126, 234, 0.12);
    color: var(--primary);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 20px;
}

.hero-text h1 {
    font-size: 48px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
}
.hero-text p {
    font-size: 18px;
    color: var(--gray);
    max-width: 500px;
    margin-bottom: 30px;
}

.hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }

.hero-stats {
    display: flex;
    gap: 48px;
    margin-top: 40px;
    padding-top: 40px;
    border-top: 1px solid rgba(0,0,0,0.06);
}
.hero-stats span {
    display: block;
    font-size: 28px;
    font-weight: 700;
    color: var(--dark);
}
.hero-stats label {
    font-size: 14px;
    color: var(--light-gray);
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}
.hero-video-preview {
    width: 100%;
    max-width: 500px;
    aspect-ratio: 16/9;
    background: linear-gradient(135deg, var(--dark), #2d2d44);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    box-shadow: 0 20px 60px rgba(0,0,0,0.15);
    cursor: pointer;
}
.hero-video-preview .play-icon {
    font-size: 64px;
    color: var(--white);
    opacity: 0.9;
    transition: var(--transition);
}
.hero-video-preview:hover .play-icon {
    transform: scale(1.1);
}
.preview-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 20px;
    background: linear-gradient(transparent, rgba(0,0,0,0.6));
    color: var(--white);
    border-radius: 0 0 var(--radius) var(--radius);
}
.preview-overlay span { font-size: 14px; opacity: 0.8; }

/* ========================================
   5. 通用部分
   ======================================== */
.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 60px;
}
.section-tag {
    display: inline-block;
    padding: 4px 16px;
    background: rgba(102, 126, 234, 0.1);
    color: var(--primary);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    margin-bottom: 12px;
}
.section-header h2 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 12px;
}
.section-header p {
    color: var(--gray);
    font-size: 18px;
}

section { padding: 80px 0; }

/* ========================================
   6. 功能亮点
   ======================================== */
.features { background: var(--white); }
.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.feature-card {
    padding: 32px 24px;
    background: var(--bg);
    border-radius: var(--radius);
    transition: var(--transition);
    text-align: center;
}
.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}
.feature-icon { font-size: 40px; margin-bottom: 16px; }
.feature-card h3 { font-size: 20px; margin-bottom: 8px; }
.feature-card p { color: var(--gray); font-size: 14px; }

/* ========================================
   7. 工作流程
   ======================================== */
.workflow { background: var(--bg); }
.workflow-steps {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.step {
    text-align: center;
    padding: 32px 24px;
    background: var(--white);
    border-radius: var(--radius);
    flex: 1;
    min-width: 200px;
    max-width: 280px;
    box-shadow: var(--shadow);
    position: relative;
}
.step-number {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    margin: 0 auto 12px;
}
.step-icon { font-size: 36px; margin-bottom: 12px; }
.step h3 { font-size: 18px; margin-bottom: 6px; }
.step p { color: var(--gray); font-size: 14px; }
.step-arrow { font-size: 28px; color: var(--primary); }

/* ========================================
   8. 价格方案
   ======================================== */
.pricing { background: var(--white); }
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    max-width: 1000px;
    margin: 0 auto;
}

.pricing-card {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 32px 28px;
    text-align: center;
    transition: var(--transition);
    position: relative;
}
.pricing-card:hover { transform: translateY(-4px); }
.pricing-card.popular {
    background: var(--white);
    box-shadow: var(--shadow);
    border: 2px solid var(--primary);
}

.popular-badge {
    position: absolute;
    top: -12px;
    right: 20px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--white);
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.pricing-header h3 { font-size: 20px; margin-bottom: 8px; }
.price { font-size: 36px; font-weight: 700; color: var(--primary); }
.price .currency { font-size: 18px; }
.pricing-header p { color: var(--gray); font-size: 14px; }

.pricing-features { text-align: left; margin: 20px 0 24px; padding: 0; }
.pricing-features li {
    padding: 6px 0;
    font-size: 14px;
    color: var(--gray);
    border-bottom: 1px solid rgba(0,0,0,0.04);
}
.pricing-features li:last-child { border-bottom: none; }

/* ========================================
   9. 用户评价
   ======================================== */
.testimonials { background: var(--bg); }
.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.testimonial-card {
    background: var(--white);
    padding: 32px 28px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.testimonial-avatar { font-size: 48px; margin-bottom: 12px; }
.testimonial-text { font-size: 16px; color: var(--gray); line-height: 1.8; }
.testimonial-author { font-weight: 600; margin-top: 16px; }
.testimonial-role { font-size: 14px; color: var(--light-gray); }

/* ========================================
   10. CTA
   ======================================== */
.cta {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--white);
    text-align: center;
    padding: 80px 0;
}
.cta h2 { font-size: 36px; margin-bottom: 12px; }
.cta p { font-size: 18px; opacity: 0.9; margin-bottom: 30px; }
.cta .btn-primary { background: var(--white); color: var(--primary); }
.cta .btn-primary:hover { box-shadow: 0 8px 40px rgba(0,0,0,0.2); }

/* ========================================
   11. 页脚
   ======================================== */
.footer {
    background: var(--dark);
    color: rgba(255,255,255,0.8);
    padding: 60px 0 20px;
}
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand .brand-icon { font-size: 32px; }
.footer-brand .brand-text {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-size: 20px;
    font-weight: 700;
    margin-left: 8px;
}
.footer-brand p { margin: 8px 0 16px; font-size: 14px; }
.footer-social { display: flex; gap: 16px; }
.footer-social a {
    font-size: 24px;
    opacity: 0.7;
    transition: var(--transition);
}
.footer-social a:hover { opacity: 1; }

.footer-links h4 { color: var(--white); margin-bottom: 16px; }
.footer-links a {
    display: block;
    padding: 4px 0;
    font-size: 14px;
    opacity: 0.7;
    transition: var(--transition);
}
.footer-links a:hover { opacity: 1; color: var(--primary); }
.footer-links p { font-size: 14px; opacity: 0.7; margin: 4px 0; }

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.06);
    padding-top: 20px;
    display: flex;
    justify-content: space-between;
    font-size: 13px;
    opacity: 0.6;
}

/* ========================================
   12. 内页
   ======================================== */
.page-header {
    padding: 140px 0 60px;
    background: linear-gradient(135deg, var(--bg), var(--white));
    text-align: center;
}
.page-header h1 { font-size: 40px; font-weight: 700; margin-bottom: 8px; }
.page-header p { color: var(--gray); font-size: 18px; }

.features-detail { background: var(--white); }
.feature-detail-item {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    padding: 60px 0;
    border-bottom: 1px solid rgba(0,0,0,0.04);
}
.feature-detail-item:last-child { border-bottom: none; }

.feature-detail-item.reverse { direction: rtl; }
.feature-detail-item.reverse > * { direction: ltr; }

.feature-tag {
    display: inline-block;
    padding: 4px 16px;
    background: rgba(102, 126, 234, 0.1);
    color: var(--primary);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    margin-bottom: 12px;
}
.feature-detail-text h2 { font-size: 32px; margin-bottom: 12px; }
.feature-detail-text p { color: var(--gray); font-size: 16px; margin-bottom: 16px; }
.feature-detail-text ul li { padding: 4px 0; font-size: 15px; color: var(--gray); }
.feature-detail-image {
    font-size: 120px;
    text-align: center;
}

/* ========================================
   13. 联系页面
   ======================================== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    padding: 16px 0;
    border-bottom: 1px solid rgba(0,0,0,0.04);
}
.contact-icon { font-size: 24px; }
.contact-item strong { display: block; }
.contact-item p { color: var(--gray); margin-top: 2px; }

.contact-form .form-group { margin-bottom: 20px; }
.contact-form label { display: block; font-weight: 500; margin-bottom: 6px; }
.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e8e8e8;
    border-radius: 8px;
    font-size: 14px;
    transition: var(--transition);
}
.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--primary);
}

/* ========================================
   14. 响应式
   ======================================== */
@media (max-width: 992px) {
    .hero-content { grid-template-columns: 1fr; text-align: center; }
    .hero-text p { margin: 0 auto 30px; }
    .hero-buttons { justify-content: center; }
    .hero-stats { justify-content: center; }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .pricing-grid { grid-template-columns: 1fr; max-width: 400px; }
    .testimonials-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .contact-grid { grid-template-columns: 1fr; }
    .feature-detail-item { grid-template-columns: 1fr; text-align: center; }
    .feature-detail-item.reverse { direction: ltr; }
    .feature-detail-image { font-size: 80px; }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 24px;
        gap: 16px;
        box-shadow: var(--shadow);
        display: none;
    }
    .nav-menu.open { display: flex; }
    .nav-actions { display: none; }
    .nav-toggle { display: flex; }
    .hero-text h1 { font-size: 32px; }
    .hero-stats { gap: 24px; flex-wrap: wrap; }
    .hero-stats span { font-size: 22px; }
    .features-grid { grid-template-columns: 1fr; }
    .workflow-steps { flex-direction: column; }
    .step-arrow { transform: rotate(90deg); }
    .footer-grid { grid-template-columns: 1fr; }
    .section-header h2 { font-size: 28px; }
    .pricing-card { padding: 24px 20px; }
}

@media (max-width: 480px) {
    .container { padding: 0 16px; }
    .hero { padding: 100px 0 60px; }
    .hero-text h1 { font-size: 28px; }
    .hero-buttons { flex-direction: column; align-items: center; }
    .btn-large { width: 100%; }
    .page-header h1 { font-size: 30px; }
}