/* ========================================
   全局样式
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #3b82f6;
    --secondary-color: #64748b;
    --text-color: #1e293b;
    --text-light: #64748b;
    --bg-color: #f8fafc;
    --white: #ffffff;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--white);
}

/* ========================================
   导航栏
   ======================================== */
.navbar {
    position: sticky;
    top: 0;
    background: var(--white);
    box-shadow: var(--shadow);
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo-content {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-text {
    font-size: 1.25rem;
    font-weight: 700;
}

.logo-domain {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-light);
    margin-top: -2px;
}

.logo-icon {
    font-size: 1.5rem;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
    font-size: 0.95rem;
}

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

.nav-auth {
    display: flex;
    gap: 1rem;
}

.nav-user {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-user-name {
    font-weight: 500;
    color: var(--text-color);
    background: var(--bg-color);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    border: 1px solid var(--border-color);
}

.btn-nav-outline {
    padding: 0.5rem 1.25rem;
    border: 2px solid var(--primary-color);
    background: transparent;
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.3s;
}

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

.btn-nav-primary {
    padding: 0.5rem 1.25rem;
    background: var(--primary-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.3s;
}

.btn-nav-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ========================================
   英雄区域
   ======================================== */
.hero {
    background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
    color: var(--white);
    padding: 5rem 2rem;
    text-align: center;
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    letter-spacing: -0.5px;
}

.hero-subtitle {
    font-size: 1.35rem;
    margin-bottom: 1rem;
    opacity: 0.95;
    font-weight: 500;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2.5rem;
    opacity: 0.9;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 4rem;
}

.btn-hero-primary {
    padding: 1rem 2.5rem;
    background: var(--white);
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s;
    box-shadow: var(--shadow-lg);
}

.btn-hero-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 25px rgba(0, 0, 0, 0.2);
}

.btn-hero-secondary {
    padding: 1rem 2.5rem;
    background: transparent;
    color: var(--white);
    text-decoration: none;
    border: 2px solid var(--white);
    border-radius: 8px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s;
}

.btn-hero-secondary:hover {
    background: var(--white);
    color: var(--primary-color);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 4rem;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.2);
}

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

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.95rem;
    opacity: 0.9;
}

/* ========================================
   通用区域样式
   ======================================== */
.section-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 5rem 2rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.section-subtitle {
    font-size: 1.15rem;
    text-align: center;
    color: var(--text-light);
    margin-bottom: 3rem;
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.feature-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: all 0.3s;
    border: 1px solid var(--border-color);
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-title {
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.feature-desc {
    color: var(--text-light);
    line-height: 1.7;
    font-size: 0.95rem;
}

/* ========================================
   功能介绍
   ======================================== */
.capabilities {
    background: var(--white);
}

.capabilities-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2.5rem;
}

.capability-item {
    display: flex;
    gap: 1.5rem;
    padding: 1.5rem;
    border-left: 4px solid var(--primary-color);
    background: var(--bg-color);
    border-radius: 8px;
    transition: all 0.3s;
}

.capability-item:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-md);
}

.capability-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    opacity: 0.3;
    flex-shrink: 0;
}

.capability-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.capability-desc {
    color: var(--text-light);
    line-height: 1.7;
    font-size: 0.95rem;
}

/* ========================================
   学术标准
   ======================================== */
.standards {
    background: var(--bg-color);
}

.standards-content {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 3rem;
    align-items: start;
}

.standards-left {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.standard-item {
    display: flex;
    gap: 1rem;
    padding: 1.5rem;
    background: var(--white);
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.standard-check {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 700;
    flex-shrink: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #eff6ff;
    border-radius: 50%;
}

.standard-text h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.standard-text p {
    color: var(--text-light);
    line-height: 1.6;
    font-size: 0.9rem;
}

.standards-right {
    position: sticky;
    top: 100px;
}

.journals-box {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    border: 2px solid var(--primary-color);
}

.journals-box h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.journals-description {
    color: var(--text-light);
    line-height: 1.7;
    font-size: 0.9rem;
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 8px;
    border-left: 3px solid var(--primary-color);
}

.journals-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.journal-tag {
    padding: 0.5rem 1rem;
    background: var(--bg-color);
    color: var(--text-color);
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
}

/* ========================================
   服务方案
   ======================================== */
.pricing {
    background: var(--white);
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
}

.pricing-card {
    background: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 2.5rem 2rem;
    transition: all 0.3s;
    position: relative;
}

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

.pricing-card.featured {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-lg);
    transform: scale(1.05);
}

.pricing-card.featured:hover {
    transform: scale(1.05) translateY(-5px);
}

.pricing-badge {
    position: absolute;
    top: -12px;
    right: 20px;
    background: var(--primary-color);
    color: var(--white);
    padding: 0.35rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.pricing-header {
    text-align: center;
    padding-bottom: 1.5rem;
    border-bottom: 2px solid var(--border-color);
    margin-bottom: 2rem;
}

.pricing-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.pricing-price {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 0.5rem;
}

.price-currency {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.price-amount {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.price-period {
    font-size: 1rem;
    color: var(--text-light);
}

.pricing-features {
    list-style: none;
    margin-bottom: 2rem;
}

.pricing-features li {
    padding: 0.75rem 0;
    color: var(--text-color);
    font-size: 0.95rem;
}

.btn-pricing {
    display: block;
    width: 100%;
    padding: 1rem;
    background: var(--primary-color);
    color: var(--white);
    text-align: center;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s;
}

.btn-pricing:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

/* ========================================
   底部
   ======================================== */
.footer {
    background: var(--text-color);
    color: var(--white);
    padding: 3rem 2rem 1.5rem;
}

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

.footer-content {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 3rem;
    margin-bottom: 2rem;
}

.footer-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-text {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.7;
    font-size: 0.9rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s;
    font-size: 0.9rem;
}

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

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.85rem;
}

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 768px) {
    .nav-menu {
        gap: 1rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .hero-stats {
        gap: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .capabilities-grid {
        grid-template-columns: 1fr;
    }
    
    .standards-content {
        grid-template-columns: 1fr;
    }
    
    .pricing-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .pricing-card.featured {
        transform: scale(1);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}