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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    color: #4a5568;
    font-size: 2rem;
    margin-bottom: 1rem;
    text-align: center;
    background: linear-gradient(45deg, #667eea, #764ba2);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

nav {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.nav-btn {
    background: linear-gradient(45deg, #667eea, #764ba2);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.nav-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.nav-btn.active {
    background: linear-gradient(45deg, #48bb78, #38a169);
    box-shadow: 0 4px 15px rgba(72, 187, 120, 0.3);
}

main {
    max-width: 1400px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.chart-container {
    background: white;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

#chart-title {
    color: #4a5568;
    font-size: 1.5rem;
}

.chart-controls {
    display: flex;
    gap: 1rem;
    align-items: center;
}

#chart-type {
    padding: 0.5rem 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    background: white;
    color: #4a5568;
    font-size: 1rem;
    cursor: pointer;
    transition: border-color 0.3s ease;
}

#chart-type:focus {
    outline: none;
    border-color: #667eea;
}

.refresh-btn {
    background: #48bb78;
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.refresh-btn:hover {
    background: #38a169;
    transform: translateY(-1px);
}

.chart-wrapper {
    position: relative;
    height: 400px;
    margin: 2rem 0;
}

.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    text-align: center;
    transition: transform 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
}

.stat-card h3 {
    color: #718096;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-value {
    color: #2d3748;
    font-size: 2rem;
    font-weight: bold;
    margin: 0;
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.grid-item {
    background: white;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
}

.grid-item h3 {
    color: #4a5568;
    margin-bottom: 1rem;
    font-size: 1.1rem;
    text-align: center;
}

.grid-item canvas {
    max-height: 250px;
}

footer {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    text-align: center;
    padding: 2rem;
    color: #718096;
    margin-top: 3rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.5rem;
    }
    
    nav {
        justify-content: center;
    }
    
    .nav-btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .chart-container {
        padding: 1rem;
    }
    
    .chart-header {
        flex-direction: column;
        text-align: center;
    }
    
    .chart-wrapper {
        height: 300px;
    }
    
    .stats-container {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
    
    .grid-container {
        grid-template-columns: 1fr;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.chart-container, .stat-card, .grid-item {
    animation: fadeIn 0.6s ease-out;
}

/* 加载动画 */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

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