/* 品牌几何知识库 - 主样式表 */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --light-color: #ecf0f1;
    --dark-color: #2c3e50;
    --text-color: #333;
    --text-light: #7f8c8d;
    --border-color: #ddd;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Inter', 'Noto Serif SC', serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #f9f9f9;
}

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

/* 导航栏 */
.navbar {
    background-color: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
}

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

.nav-brand h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-brand .tagline {
    font-size: 0.9rem;
    color: var(--secondary-color);
    font-weight: 500;
    margin-top: 2px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 8px 12px;
    border-radius: 4px;
    transition: var(--transition);
}

.nav-menu a:hover,
.nav-menu a.active {
    background-color: var(--light-color);
    color: var(--secondary-color);
}

/* 英雄区域 */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, #34495e 100%);
    color: white;
    padding: 4rem 0;
    margin-bottom: 3rem;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--light-color);
    margin-bottom: 1.5rem;
}

.hero-content p {
    margin-bottom: 2rem;
    font-size: 1.1rem;
    opacity: 0.9;
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--secondary-color);
    color: white;
    padding: 12px 24px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.btn-primary:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.quote-box {
    background-color: rgba(255, 255, 255, 0.1);
    padding: 2rem;
    border-radius: 8px;
    border-left: 4px solid var(--secondary-color);
}

.quote-box i {
    font-size: 1.5rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.quote-box p {
    font-size: 1.2rem;
    font-style: italic;
    margin-bottom: 1rem;
}

.quote-box cite {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* 特色区域 */
.featured-section {
    padding: 3rem 0;
}

.featured-section h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.book-card {
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.book-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
}

.book-cover {
    height: 200px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 3rem;
}

.book-content {
    padding: 1.5rem;
}

.book-content h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.book-author {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.book-excerpt {
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.book-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-bottom: 1rem;
}

.tag {
    background-color: var(--light-color);
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
    color: var(--text-light);
}

.book-link {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
}

/* 主编寄语 */
.editor-note {
    background-color: var(--light-color);
    padding: 3rem 0;
    margin: 3rem 0;
}

.editor-card {
    background-color: white;
    border-radius: 8px;
    padding: 2rem;
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: 2rem;
    box-shadow: var(--shadow);
}

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

.avatar-circle {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, var(--secondary-color) 0%, #2ecc71 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-size: 3rem;
    color: white;
}

.editor-avatar h4 {
    font-size: 1.2rem;
    margin-bottom: 5px;
}

.editor-avatar p {
    color: var(--text-light);
    font-size: 0.9rem;
}

.editor-content h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.editor-content p {
    margin-bottom: 1rem;
    line-height: 1.8;
}

.signature {
    font-style: italic;
    color: var(--text-light);
    border-left: 3px solid var(--secondary-color);
    padding-left: 1rem;
    margin-top: 1.5rem;
}

/* 页脚 */
.footer {
    background-color: var(--dark-color);
    color: white;
    padding: 3rem 0 1.5rem;
    margin-top: 3rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-brand h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-links h4,
.footer-contact h4 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
}

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

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #bdc3c7;
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-contact p {
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-contact a {
    color: #bdc3c7;
    text-decoration: none;
}

.footer-contact a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 1.5rem;
    text-align: center;
    color: #bdc3c7;
    font-size: 0.9rem;
}

.footer-note {
    font-style: italic;
    margin-top: 0.5rem;
    opacity: 0.8;
}

/* 加载状态 */
.loading {
    text-align: center;
    padding: 2rem;
    color: var(--text-light);
}

.loading i {
    margin-right: 10px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero .container {
        grid-template-columns: 1fr;
    }
    
    .nav-menu {
        display: none;
    }
    
    .editor-card {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .featured-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-content h2 {
        font-size: 2rem;
    }
}