/* 全局样式 */
body {
    font-family: 'Microsoft YaHei', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
}

/* 导航栏样式 */
.navbar {
    background: linear-gradient(135deg, #2c3e50 0%, #3498db 50%, #9b59b6 100%) !important;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.navbar-brand {
    font-weight: bold;
    font-size: 1.3rem;
}

.navbar-nav .nav-link {
    font-weight: 500;
    transition: all 0.3s ease;
}

.navbar-nav .nav-link:hover {
    background-color: rgba(255,255,255,0.1);
    border-radius: 5px;
}

.navbar-text {
    background-color: rgba(255,255,255,0.1);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
}

/* 首页英雄区域 */
.hero-section {
    background: linear-gradient(135deg, rgba(255,255,255,0.9) 0%, rgba(255,255,255,0.7) 100%);
    min-height: 100vh;
}

.display-4 {
    background: linear-gradient(135deg, #2c3e50, #3498db);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 统计卡片网格 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    margin-top: 2rem;
}

.stat-card {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.stat-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 1rem;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-icon i {
    font-size: 1.5rem;
    color: white;
}

.stat-content h3 {
    font-size: 1.3rem;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.stat-content p {
    color: #7f8c8d;
    margin: 0;
    font-size: 0.9rem;
}

/* 报告列表样式 */
.report-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    margin-bottom: 2rem;
}

.report-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.report-card-header {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    padding: 1.5rem;
}

.report-card-body {
    padding: 1.5rem;
}

.report-card-title {
    font-size: 1.2rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.report-card-date {
    font-size: 0.8rem;
    opacity: 0.9;
}

.report-card-info {
    color: #7f8c8d;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.report-card-actions {
    /* 按钮区域样式 */
}

/* 内容页面切换 */
.content-page {
    transition: opacity 0.3s ease;
}

/* 下拉菜单样式 */
.dropdown-menu {
    max-height: 400px;
    overflow-y: auto;
    border: none;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.dropdown-item {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid #f8f9fa;
    transition: background-color 0.2s ease;
}

.dropdown-item:hover {
    background-color: #f8f9fa;
}

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

.dropdown-item .report-date {
    font-size: 0.8rem;
    color: #6c757d;
    display: block;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .stat-card {
        padding: 1.5rem;
    }
    
    .display-4 {
        font-size: 2.5rem;
    }
    
    .hero-section {
        padding: 2rem 0;
    }
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* 空状态样式 */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: #7f8c8d;
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

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

.empty-state p {
    max-width: 400px;
    margin: 0 auto;
}