/* CSS Variables for Theme */
:root {
    --color-primary: #1a1a1a;
    --color-secondary: #666;
    --color-accent: #2196F3;
    --color-background: #ffffff;
    --color-surface: #f8f9fa;
    --color-border: #e6e6e6;
    --color-text: #1a1a1a;
    --color-text-secondary: #666;
    --color-hover: #f5f5f5;
    --color-success: #4CAF50;
    --color-warning: #FF9800;
    
    --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --border-radius-xl: 16px;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-primary: #ffffff;
    --color-secondary: #b3b3b3;
    --color-background: #0f0f0f;
    --color-surface: #1a1a1a;
    --color-border: #333;
    --color-text: #ffffff;
    --color-text-secondary: #b3b3b3;
    --color-hover: #2a2a2a;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-primary);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
    margin-bottom: var(--spacing-md);
}

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

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

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

/* Header */
.header {
    position: sticky;
    top: 0;
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
    backdrop-filter: blur(10px);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo-link {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.025em;
}

.nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--color-text);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    transition: background-color var(--transition-fast);
}

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

.theme-toggle {
    background: none;
    border: none;
    font-size: var(--font-size-lg);
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: var(--border-radius);
    transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
    background-color: var(--color-hover);
}

/* Hero Section */
.hero {
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-background) 100%);
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: 0;
}

.hero-image {
    border-radius: var(--border-radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-xl);
}

.hero-image img {
    width: 100%;
    height: 300px;
    object-fit: cover;
}

/* Categories Navigation */
.categories-nav {
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
}

.categories-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    gap: var(--spacing-md);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.category-btn {
    background: none;
    border: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    flex-shrink: 0;
}

.category-btn:hover,
.category-btn.active {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
    color: white;
}

/* Main Content */
.main {
    padding: var(--spacing-2xl) 0;
}

.main-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: var(--spacing-2xl);
}

/* Articles Section */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.article-card {
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
    cursor: pointer;
    height: fit-content;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.article-image {
    width: 100%;
    height: 100%;
    overflow: clip;
}

.article-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-normal);
}

.article-card:hover .article-image img {
    transform: scale(1.05);
}

.article-content {
    padding: var(--spacing-lg);
}

.article-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.article-summary {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
}

.article-author {
    font-weight: 500;
    color: var(--color-primary);
}

.article-date {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

.article-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.article-read-time {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

.article-tags {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.article-tag {
    background-color: var(--color-surface);
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius);
    font-size: var(--font-size-xs);
    font-weight: 500;
}

/* Sidebar */
.sidebar {
    position: sticky;
    top: 80px;
    height: fit-content;
}

.sidebar-section {
    background-color: var(--color-surface);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.sidebar-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary);
}

/* Author Card */
.author-card {
    display: flex;
    gap: var(--spacing-md);
    align-items: flex-start;
}

.author-avatar {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-accent) 0%, #64B5F6 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.avatar-emoji {
    font-size: var(--font-size-2xl);
}

.author-name {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.author-bio {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    margin-bottom: 0;
}

/* Tags Cloud */
.tags-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.tag {
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius);
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.tag:hover {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
    color: white;
}

/* Categories Info */
.category-info {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.category-info:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.category-info h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-primary);
}

.category-info p {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    margin-bottom: 0;
}

/* Loading */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    color: var(--color-text-secondary);
}

.loading.hidden {
    display: none;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-border);
    border-top: 3px solid var(--color-accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--spacing-md);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Footer */
.footer {
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-2xl) 0;
    margin-top: var(--spacing-3xl);
    position: relative;
    overflow: hidden;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    text-align: center;
}

.footer-content p {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
}

.footer-content p:last-child {
    margin-bottom: 0;
}

/* Cat Animation */
.cat-animation {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100px;
    pointer-events: none;
}

.cat-container {
    position: absolute;
    bottom: 10px;
    left: 0;
    width: 60px;
    height: 60px;
    /* 移除CSS动画，使用JavaScript控制 */
}

.cat-sprite {
    width: 60px;
    height: 60px;
    object-fit: contain;
    image-rendering: crisp-edges;
    transition: transform 0.1s ease-out;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

/* 小猫在暗色主题下的效果 */
[data-theme="dark"] .cat-sprite {
    filter: drop-shadow(0 2px 4px rgba(255, 255, 255, 0.1));
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    animation: fadeIn var(--transition-normal);
}

.modal.show {
    display: block;
}

.modal-content {
    background-color: var(--color-background);
    margin: 5% auto;
    padding: 0;
    border-radius: var(--border-radius-lg);
    width: 90%;
    max-width: 600px;
    max-height: 80vh;
    overflow-y: auto;
    animation: slideDown var(--transition-normal);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.modal-header h2 {
    margin: 0;
    color: var(--color-primary);
}

.modal-close {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--color-text-secondary);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--border-radius);
    transition: background-color var(--transition-fast);
}

.modal-close:hover {
    background-color: var(--color-hover);
}

.modal-body {
    padding: var(--spacing-lg);
}

/* About Content */
.about-content {
    display: flex;
    gap: var(--spacing-lg);
}

.about-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-accent) 0%, #64B5F6 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.about-emoji {
    font-size: var(--font-size-3xl);
}

.about-text h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.about-text p {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.about-skills,
.about-contact {
    margin-top: var(--spacing-lg);
}

.about-skills h4,
.about-contact h4 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-size: var(--font-size-base);
}

.about-skills ul {
    list-style: none;
    padding: 0;
}

.about-skills li {
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) 0;
    position: relative;
    padding-left: var(--spacing-lg);
}

.about-skills li::before {
    content: "▶";
    position: absolute;
    left: 0;
    color: var(--color-accent);
    font-size: var(--font-size-xs);
}

.about-contact p {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-container {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .sidebar {
        position: static;
        order: -1;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 768px) {
    .header-container {
        padding: 0 var(--spacing-md);
    }
    
    .hero {
        padding: var(--spacing-2xl) 0;
    }
    
    .hero-container {
        padding: 0 var(--spacing-md);
        gap: var(--spacing-xl);
    }
    
    .hero-title {
        font-size: var(--font-size-3xl);
    }
    
    .hero-subtitle {
        font-size: var(--font-size-base);
    }
    
    .categories-container {
        padding: 0 var(--spacing-md);
    }
    
    .main-container {
        padding: 0 var(--spacing-md);
    }
    
    .articles-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .footer-container {
        padding: 0 var(--spacing-md);
    }
    
    .about-content {
        flex-direction: column;
        text-align: center;
    }
    
    .modal-content {
        margin: 10% auto;
        width: 95%;
    }
}

@media (max-width: 480px) {
    .nav {
        gap: var(--spacing-sm);
    }
    
    .nav-link {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: var(--font-size-sm);
    }
    
    .hero-title {
        font-size: var(--font-size-2xl);
    }
    
    .sidebar-section {
        padding: var(--spacing-md);
    }
    
    .article-content {
        padding: var(--spacing-md);
    }
    
    .category-btn {
        padding: var(--spacing-xs) var(--spacing-md);
        font-size: var(--font-size-sm);
    }
}

/* Print Styles */
@media print {
    .header,
    .categories-nav,
    .sidebar,
    .footer,
    .modal {
        display: none;
    }
    
    .main-container {
        grid-template-columns: 1fr;
        max-width: 100%;
        padding: 0;
    }
    
    .article-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000;
        --color-text-secondary: #333;
    }
    
    [data-theme="dark"] {
        --color-border: #fff;
        --color-text-secondary: #ccc;
    }
}