body {
    font-family: 'Microsoft YaHei', sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.header {
    text-align: center;
    margin-bottom: 50px;
}

h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 15px;
    font-size: 2.8em;
    font-weight: bold;
}

.subtitle {
    font-family: 'Ma Shan Zheng', cursive;
    color: #666;
    font-size: 1.4em;
    margin-top: 10px;
    letter-spacing: 2px;
}

.year-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 40px;
}

.year-buttons button {
    padding: 12px 35px;
    font-size: 18px;
    border: none;
    border-radius: 25px;
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 5px rgba(76,175,80,0.3);
}

.year-buttons button:hover {
    background-color: #45a049;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(76,175,80,0.4);
}

.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
    margin-top: 30px;
    padding: 20px;
}

.subject-card {
    padding: 25px;
    text-align: center;
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 1px solid #e0e0e0;
}

.subject-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
    border-color: #4CAF50;
}

#download-container {
    text-align: center;
    margin-top: 40px;
    padding: 30px;
    background-color: #f8f9fa;
    border-radius: 10px;
}

.download-btn {
    display: inline-block;
    margin: 20px auto;
    padding: 15px 50px;
    font-size: 18px;
    background-color: #2196F3;
    color: white;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 5px rgba(33,150,243,0.3);
}

.download-btn:hover {
    background-color: #1976D2;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(33,150,243,0.4);
}

.cloud-download {
    margin-top: 25px;
}

.cloud-link {
    color: #4CAF50;
    text-decoration: underline;
    font-size: 16px;
    transition: color 0.3s ease;
    position: relative;
    padding-bottom: 2px;
}

.cloud-link:hover {
    color: #45a049;
}

.cloud-link::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: #4CAF50;
}

@media (max-width: 768px) {
    .subjects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .year-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .year-buttons button {
        width: 80%;
    }
}

@media (max-width: 480px) {
    .subjects-grid {
        grid-template-columns: 1fr;
    }
    
    h1 {
        font-size: 1.8em;
    }
}