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

:root {
    --primary-color: #2563eb;
    --secondary-color: #64748b;
    --background-color: #ffffff;
    --text-color: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --card-background: #f8fafc;
    --hover-color: #f1f5f9;
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

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

/* 头部 */
.header {
    background: var(--background-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

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

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

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    transition: all 0.2s;
}

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

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

/* 主要内容区 */
.main {
    min-height: calc(100vh - 140px);
    padding: 2rem 0;
}

.section {
    display: none;
}

.section.active {
    display: block;
}

/* Hero 区域 */
.hero {
    text-align: center;
    padding: 4rem 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 1rem;
    margin-bottom: 3rem;
}

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

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* 文章列表 */
.posts-container h3 {
    margin-bottom: 2rem;
    font-size: 1.5rem;
    color: var(--text-color);
}

.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.post-card {
    background: var(--card-background);
    border-radius: 0.75rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    transition: all 0.2s;
    cursor: pointer;
}

.post-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

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

.post-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.post-category {
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.75rem;
}

.post-excerpt {
    color: var(--text-muted);
    line-height: 1.5;
    margin-bottom: 1rem;
}

.post-content {
    color: var(--text-color);
    line-height: 1.8;
}

.read-more {
    color: var(--primary-color);
    font-weight: 500;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
}

.read-more:hover {
    text-decoration: underline;
}

/* 关于页面 */
.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-content h2 {
    margin-bottom: 2rem;
    font-size: 2rem;
    color: var(--text-color);
}

.about-content p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 2rem;
    color: var(--text-muted);
}

.interests {
    background: var(--card-background);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
}

.interests h4 {
    margin-bottom: 1rem;
    color: var(--text-color);
}

.interests ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.5rem;
}

.interests li {
    padding: 0.5rem 0;
    color: var(--text-muted);
}

/* 写文章页面 */
.write-container {
    max-width: 800px;
    margin: 0 auto;
}

.write-container h2 {
    margin-bottom: 2rem;
    font-size: 2rem;
    color: var(--text-color);
}

.post-form {
    background: var(--card-background);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
    font-family: inherit;
    background: var(--background-color);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(37 99 235 / 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 200px;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
}

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

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
    margin-bottom: 2rem;
}

.btn-secondary:hover {
    background: #475569;
}

/* 文章详情页 */
.post-detail-container {
    max-width: 800px;
    margin: 0 auto;
}

#detail-article {
    background: var(--background-color);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
}

#detail-article .post-title {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

#detail-article .post-content {
    margin-top: 2rem;
    line-height: 1.8;
    white-space: pre-wrap;
}

/* 页脚 */
.footer {
    background: var(--card-background);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 4rem;
    text-align: center;
}

.footer p {
    color: var(--text-muted);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    .nav {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-links {
        gap: 1rem;
    }
    
    .hero {
        padding: 2rem 1rem;
    }
    
    .hero h2 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .posts-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .post-form {
        padding: 1.5rem;
    }
    
    .interests ul {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .hero h2 {
        font-size: 1.5rem;
    }
    
    .post-card {
        padding: 1rem;
    }
    
    .write-container {
        padding: 0;
    }
    
    .post-form {
        padding: 1rem;
    }
}

/* 登录页面样式 */
.login-container {
    max-width: 400px;
    margin: 0 auto;
    padding: 2rem;
}

.login-container h2 {
    margin-bottom: 2rem;
    font-size: 2rem;
    color: var(--text-color);
    text-align: center;
}

.login-form {
    background: var(--card-background);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
}

.login-form .form-group {
    margin-bottom: 1.5rem;
}

.login-form input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
    background: var(--background-color);
}

.login-form input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(37 99 235 / 0.1);
}

.error-message {
    margin-top: 1rem;
    padding: 0.75rem;
    background: #fef2f2;
    border: 1px solid #fecaca;
    border-radius: 0.5rem;
    color: #dc2626;
    text-align: center;
}

/* 管理页面样式 */
.admin-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

.admin-container h2 {
    margin-bottom: 2rem;
    font-size: 2rem;
    color: var(--text-color);
}

.admin-tabs {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
}

.tab-btn {
    padding: 0.75rem 1rem;
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    font-size: 1rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s;
}

.tab-btn:hover {
    color: var(--primary-color);
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.admin-actions {
    margin-bottom: 2rem;
}

.users-list {
    background: var(--card-background);
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.user-item {
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.user-item:last-child {
    border-bottom: none;
}

.user-info {
    flex: 1;
}

.user-name {
    font-weight: 600;
    color: var(--text-color);
}

.user-role {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.user-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-danger {
    background: #dc2626;
    color: white;
}

.btn-danger:hover {
    background: #b91c1c;
}

.settings-form {
    background: var(--card-background);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border-color);
}

.admin-footer {
    margin-top: 2rem;
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

/* 添加用户模态框 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
}

.modal-content {
    position: relative;
    background: var(--background-color);
    margin: 5% auto;
    padding: 2rem;
    width: 90%;
    max-width: 500px;
    border-radius: 0.75rem;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.modal-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-color);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
}

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

/* 加载动画 */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    color: var(--text-muted);
}

.loading::after {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-top: 2px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-left: 1rem;
}

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

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-muted);
}

.empty-state h3 {
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.empty-state p {
    margin-bottom: 2rem;
}