/* =========================================
   全局重置与变量
   ========================================= */
:root {
    --primary-color: #1e40af; /* Deep Tech Blue */
    --primary-hover: #1e3a8a;
    --text-main: #1e293b; /* Slate 800 - Professional Grey */
    --text-light: #475569; /* Slate 600 */
    --text-muted: #94a3b8; /* Slate 400 */
    --bg-white: #ffffff;
    --bg-light: #f1f5f9; /* Slate 100 */
    --border-color: #e2e8f0; /* Slate 200 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --transition: all 0.3s ease;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    color: var(--text-main);
    line-height: 1.6;
    background-color: var(--bg-white);
    -webkit-font-smoothing: antialiased;
    font-size: 16px;
}

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

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

ul {
    list-style: none;
}

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

/* =========================================
   排版与基础样式
   ========================================= */
h1, h2, h3, h4, h5, h6 {
    color: var(--text-main);
    line-height: 1.2;
    margin-bottom: 1rem;
    font-weight: 700;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-padding {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.2rem;
    margin-bottom: 3rem;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
    max-width: 700px;
    margin: -2rem auto 3rem;
}

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

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

/* =========================================
   按钮
   ========================================= */
.btn {
    display: inline-block;
    padding: 10px 24px;
    border-radius: 6px;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    border: 2px solid transparent;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
    color: #fff;
}

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

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

.btn-large {
    padding: 14px 32px;
    font-size: 1.1rem;
}

.btn-sm {
    padding: 6px 16px;
    font-size: 0.9rem;
}

.btn-block {
    display: block;
    width: 100%;
}

/* =========================================
   网格系统
   ========================================= */
.grid {
    display: grid;
    gap: 30px;
}

.grid-3 {
    grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* =========================================
   导航栏 (Navbar)
   ========================================= */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    transition: var(--transition);
}

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

.brand-logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    font-size: 1.8rem;
}

.nav-menu {
    display: flex;
    align-items: center;
    flex-grow: 1;
    justify-content: flex-end;
    gap: 30px;
}

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

.nav-links a {
    color: var(--text-light);
    font-weight: 500;
}

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

.nav-actions {
    display: flex;
    gap: 12px;
}

/* 移动端汉堡菜单按钮 (纯CSS) */
.nav-toggle {
    display: none;
}

.nav-toggle-label {
    display: none;
    cursor: pointer;
    padding: 10px;
}

.nav-toggle-label span,
.nav-toggle-label span::before,
.nav-toggle-label span::after {
    display: block;
    background: var(--text-main);
    height: 3px;
    width: 24px;
    border-radius: 2px;
    position: relative;
    transition: var(--transition);
}

.nav-toggle-label span::before,
.nav-toggle-label span::after {
    content: '';
    position: absolute;
}

.nav-toggle-label span::before { bottom: 8px; }
.nav-toggle-label span::after { top: 8px; }

/* =========================================
   首屏横幅区 (Hero Section)
   ========================================= */
.hero-section {
    padding: 160px 0 100px;
    text-align: center;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.promo-tag {
    display: inline-block;
    background-color: #fee2e2;
    color: #dc2626;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.hero-section h1 {
    font-size: 3.5rem;
    letter-spacing: -1px;
    margin-bottom: 24px;
    color: #0f172a; /* Slate 900 */
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: 40px;
}

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

/* =========================================
   核心优势图卡区
   ========================================= */
.feature-card {
    background: var(--bg-white);
    padding: 30px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* =========================================
   定价卡片区
   ========================================= */
.pricing-grid {
    align-items: center;
}

.pricing-card {
    background: var(--bg-white);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    padding: 40px 30px;
    text-align: center;
    position: relative;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.pricing-card:hover {
    box-shadow: var(--shadow-lg);
}

.pricing-card.recommended {
    border: 2px solid var(--primary-color);
    transform: scale(1.05);
    box-shadow: var(--shadow-md);
    z-index: 2;
}

.recommended-badge {
    position: absolute;
    top: -16px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: #fff;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: bold;
    white-space: nowrap;
}

.card-header h3 {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 15px;
}

.price {
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 5px;
}

.price span {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: normal;
}

.billing-cycle {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 30px;
}

.pricing-features {
    text-align: left;
    margin-bottom: 30px;
}

.pricing-features li {
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-light);
    font-size: 0.95rem;
}

.pricing-features li:last-child {
    border-bottom: none;
}

.pricing-features li::before {
    content: '✓';
    color: #10b981;
    margin-right: 10px;
    font-weight: bold;
}

/* =========================================
   多平台支持区
   ========================================= */
.platform-card {
    background: var(--bg-light);
    padding: 30px 20px;
    border-radius: 12px;
    text-align: center;
    border: 1px solid var(--border-color);
}

.platform-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.platform-card h3 {
    margin-bottom: 10px;
}

.platform-card p {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 20px;
}

/* =========================================
   深度特性区 (Why Choose)
   ========================================= */
.why-card {
    text-align: center;
    padding: 20px;
}

.why-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.why-card h4 {
    font-size: 1.25rem;
    margin-bottom: 15px;
}

.why-card p {
    color: var(--text-light);
}

/* =========================================
   用户评价跑马灯区
   ========================================= */
.overflow-hidden {
    overflow: hidden;
}

.marquee-container {
    width: 100%;
    overflow: hidden;
    position: relative;
    padding: 20px 0;
}

.marquee-container::before,
.marquee-container::after {
    content: "";
    position: absolute;
    top: 0;
    width: 100px;
    height: 100%;
    z-index: 2;
}

.marquee-container::before {
    left: 0;
    background: linear-gradient(to right, var(--bg-white) 0%, transparent 100%);
}

.marquee-container::after {
    right: 0;
    background: linear-gradient(to left, var(--bg-white) 0%, transparent 100%);
}

.marquee-content {
    display: flex;
    gap: 30px;
    width: max-content;
    animation: marquee 30s linear infinite;
}

.marquee-content:hover {
    animation-play-state: paused;
}

.testimonial-card {
    width: 350px;
    background: var(--bg-light);
    padding: 30px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    flex-shrink: 0;
}

.stars {
    color: #f59e0b;
    font-size: 1.2rem;
    margin-bottom: 15px;
    letter-spacing: 2px;
}

.review-text {
    font-style: italic;
    color: var(--text-light);
    margin-bottom: 20px;
    line-height: 1.6;
}

.user-info {
    font-weight: 600;
    color: var(--text-main);
    text-align: right;
}

@keyframes marquee {
    0% { transform: translateX(0); }
    100% { transform: translateX(calc(-50% - 15px)); } /* 50%因为复制了一半卡片 */
}

/* =========================================
   常见问题区 (FAQ)
   ========================================= */
.faq-container {
    max-width: 800px;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.faq-item {
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}

.faq-item summary {
    padding: 20px;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    list-style: none; /* 去除默认箭头 */
    position: relative;
    outline: none;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.faq-item[open] summary::after {
    content: '−';
}

.faq-answer {
    padding: 0 20px 20px;
    color: var(--text-light);
    line-height: 1.6;
    border-top: 1px solid transparent;
}

.faq-item[open] .faq-answer {
    border-top-color: var(--border-color);
    padding-top: 20px;
}

/* =========================================
   底部转化区与页脚
   ========================================= */
.bottom-cta-section {
    background: var(--primary-color);
    color: #fff;
}

.bottom-cta-section h2 {
    color: #fff;
    margin-bottom: 15px;
}

.bottom-cta-section p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.bottom-cta-section .btn-primary {
    background: #fff;
    color: var(--primary-color);
    border-color: #fff;
}

.bottom-cta-section .btn-primary:hover {
    background: var(--bg-light);
}

.footer {
    background: #0f172a; /* Slate 900 */
    color: #94a3b8; /* Slate 400 */
    padding: 60px 0 30px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 30px;
    margin-bottom: 30px;
}

.footer-links a {
    color: #9ca3af;
}

.footer-links a:hover {
    color: #fff;
}

.copyright {
    font-size: 0.9rem;
    border-top: 1px solid #374151;
    padding-top: 30px;
}

/* =========================================
   媒体查询 (响应式适配)
   ========================================= */
@media (max-width: 992px) {
    .grid-3, .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .pricing-card.recommended {
        transform: none;
    }
}

@media (max-width: 768px) {
    .hero-section h1 {
        font-size: 2.5rem;
    }
    
    .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }
    
    .nav-toggle-label {
        display: block;
        z-index: 1001;
    }
    
    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 300px;
        height: 100vh;
        background: var(--bg-white);
        flex-direction: column;
        justify-content: flex-start;
        padding: 80px 30px 30px;
        transition: var(--transition);
        box-shadow: -5px 0 15px rgba(0,0,0,0.1);
    }
    
    .nav-links {
        flex-direction: column;
        width: 100%;
        gap: 20px;
        margin-bottom: 30px;
    }
    
    .nav-links a {
        display: block;
        font-size: 1.1rem;
        padding: 10px 0;
        border-bottom: 1px solid var(--border-color);
    }
    
    .nav-actions {
        flex-direction: column;
        width: 100%;
    }
    
    /* 菜单展开状态 */
    .nav-toggle:checked ~ .nav-menu {
        right: 0;
    }
    
    .nav-toggle:checked ~ .nav-toggle-label span {
        background: transparent;
    }
    
    .nav-toggle:checked ~ .nav-toggle-label span::before {
        transform: rotate(45deg);
        bottom: 0;
        background: var(--text-main);
    }
    
    .nav-toggle:checked ~ .nav-toggle-label span::after {
        transform: rotate(-45deg);
        top: 0;
        background: var(--text-main);
    }
}

@media (max-width: 480px) {
    .hero-section h1 {
        font-size: 2rem;
    }
    
    .section-padding {
        padding: 50px 0;
    }
    
    .btn-large {
        padding: 12px 24px;
    }
    
    .price {
        font-size: 2.5rem;
    }
}