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

body {
    text-align: center;
    font-family: 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
    background-color: #f8f9fa;
    color: #333;
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
}

#main_content {
    max-width: 1000px;
    background-color: #ffffff;
    margin: 30px auto;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

h1 {
    color: #2d3748;
    margin-bottom: 40px;
    font-size: 32px;
    font-weight: 700;
    position: relative;
    padding-bottom: 15px;
}

h1::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background-color: #3182ce;
    border-radius: 2px;
}

h2 {
    color: #4a5568;
    margin: 30px 0 25px;
    font-size: 20px;
    font-weight: 600;
    position: relative;
    display: inline-block;
}

h2::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: #e2e8f0;
    border-radius: 2px;
}

#local_tool_list,
#external_tool_list {
    margin: 0 0 30px;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
}

#local_tool_list li,
#external_tool_list li {
    list-style: none;
    background-color: #3182ce;
    border-radius: 8px;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

#local_tool_list li:hover,
#external_tool_list li:hover {
    background-color: #2c5282;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

#local_tool_list li a,
#external_tool_list li a {
    display: block;
    text-decoration: none;
    color: #ffffff;
    padding: 16px 12px;
    font-size: 14px;
    font-weight: 500;
    white-space: normal;
    word-wrap: break-word;
    line-height: 1.4;
}

#external_tool_list li {
    background-color: #38a169;
}

#external_tool_list li:hover {
    background-color: #2f855a;
}

@media screen and (max-width: 768px) {
    #main_content {
        margin: 20px;
        padding: 30px;
    }

    h1 {
        font-size: 28px;
        margin-bottom: 30px;
    }

    h2 {
        font-size: 20px;
        margin: 5px 0 20px;
    }

    #local_tool_list,
    #external_tool_list {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
        gap: 14px;
    }

    #local_tool_list li a,
    #external_tool_list li a {
        padding: 14px 10px;
        font-size: 13px;
    }
}

@media screen and (max-width: 480px) {
    body {
        padding: 10px;
    }

    #main_content {
        margin: 10px;
        padding: 20px;
    }

    h1 {
        font-size: 24px;
        margin-bottom: 25px;
    }

    h2 {
        font-size: 18px;
        margin: 5px 0 20px;
    }

    #local_tool_list,
    #external_tool_list {
        grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
        gap: 12px;
    }

    #local_tool_list li a,
    #external_tool_list li a {
        padding: 12px 8px;
        font-size: 12px;
    }
}