* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "PingFang SC",-apple-system,BlinkMacSystemFont,"Helvetica Neue",Helvetica,Arial,"Microsoft YaHei","Source Han Sans SC",sans-serif;
}

body {
    background-color: #f5f5f5;
    color: #383838;
    line-height: 1.6;
    font-size: 15px;
}

a {
    text-decoration: none;
    color: #333;
    transition: color 0.3s ease;
}

a:hover {
    color: #c00;
}

ul {
    list-style: none;
}

/* 核心容器（保留原有，固定1000px） */
.container {
    width: 100%;
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 15px;
}

/* 顶部导航栏（完全保留原有） */
.top-nav {
    background-color: #222;
    color: #ccc;
    padding: 8px 0;
    font-size: 15px;
    position: sticky;
    top: 0;
    z-index: 999;
}

.top-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.top-nav-left {
    display: flex;
    gap: 20px;
}

.top-nav-right {
    display: flex;
    gap: 20px;
}

.top-nav a {
    color: #ccc;
}

.top-nav a:hover {
    color: #fff;
}

/* 主导航栏（完全保留原有） */
.main-nav {
    background-color: #fff;
    border-bottom: 2px solid #c00;
    padding: 12px 0;
    position: sticky;
    top: 38px;
    z-index: 999;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.main-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: #c00;
}

.nav-menu {
    display: flex;
    gap: 25px;
}

.nav-menu li a {
    font-size: 18px;
    font-weight: bold;
}

.search-box {
    display: flex;
    align-items: center;
    gap: 5px;
}

.search-box input {
    padding: 6px 10px;
    border: 1px solid #ddd;
    border-radius: 3px;
    outline: none;
    font-size: 14px;
    width: 180px;
}

.search-box button {
    padding: 6px 12px;
    background-color: #c00;
    color: #fff;
    border: none;
    border-radius: 3px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.search-box button:hover {
    background-color: #a00;
}

.express-container {
    display: flex;
    gap: 20px;
    margin: 20px 0 30px;
}

.express-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.search-box-wrapper {
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.search-label {
    font-size: 16px;
    font-weight: 500;
    color: #333;
    min-width: 80px;
}

.search-input-group {
    flex: 1;
    display: flex;
    gap: 10px;
}

.search-input {
    flex: 1;
    padding: 12px 15px;
    border: 1px solid #e0e0e0;
    border-radius: 6px;
    outline: none;
    font-size: 14px;
    transition: border-color 0.3s ease;
}

.search-input:focus {
    border-color: #c00;
    box-shadow: 0 0 0 2px rgba(204, 0, 0, 0.1);
}

.search-btn {
    padding: 12px 30px;
    background-color: #c00;
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: background-color 0.3s ease;
    white-space: nowrap;
}

.search-btn:hover {
    background-color: #a00;
}

/* 左侧侧边栏（保留原有） */
.express-sidebar {
    width: 200px;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    padding: 15px;
    height: fit-content;
    position: sticky;
    top: 80px;
}

.sidebar-title {
    font-size: 18px;
    font-weight: 600;
    color: #333;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #f0f0f0;
    display: flex;
    align-items: center;
    gap: 8px;
}

.sidebar-title i {
    color: #c00;
    font-size: 20px;
}

.collapse-list {
    display: flex;
    flex-direction: column;
    gap: 5px;
}

/* 一级列表项 */
.collapse-item {
    border-radius: 6px;
    overflow: hidden;
    border: 1px solid #f0f0f0;
}

/* 一级列表标题（可点击） */
.collapse-header {
    padding: 10px 12px;
    background-color: #f9f9f9;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 17px;
    font-weight: 500;
    transition: all 0.2s ease;
    color: #222;
}

.collapse-header:hover {
    background-color: #f0f0f0;
    color: #c00;
}

/* 展开/收起图标 */
.collapse-icon {
    font-size: 12px;
    color: #666;
    transition: transform 0.2s ease;
}

.collapse-icon.expanded {
    transform: rotate(90deg);
    color: #c00;
}

/* 二级列表容器 */
.collapse-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    background-color: #fff;
}

/* 二级列表展开状态 */
.collapse-content.expanded {
    max-height: 500px; /* 足够大的高度容纳所有二级项 */
}

/* 二级列表项 */
.collapse-subitem {
    padding: 10px 15px;
    font-size: 14px;
    color: #222;
    transition: all 0.2s ease;
    cursor: pointer;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 21px;
}

.collapse-subitem:hover {
    background-color: #fff0f0;
    color: #c00;
    padding-left: 18px;
}

.collapse-subitem.active {
    background-color: #fff0f0;
    color: #c00;
    font-weight: 500;
    border-left: 2px solid #c00;
}


/* 工具地图卡片（保留原有） */
.tool-map-card {
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    padding: 30px;
}

.tool-title {
    font-size: 22px;
    font-weight: 600;
    color: #333;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid #f0f0f0;
}

/* 工具地图一级分类容器 - 单列布局 */
.tool-map-container {
    display: flex; /* 替换grid为flex单列 */
    flex-direction: column;
    gap: 30px; /* 增大分类间间距，提升可读性 */
}

/* 一级分类样式 - 优化单列布局的视觉效果 */
.tool-category {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 15px;
    border-radius: 8px;
    background-color: #f9f9f9;
}

.category-title {
    font-size: 18px;
    font-weight: 600;
    color: #333;
    padding-bottom: 8px;
    border-bottom: 1px solid #e0e0e0;
    margin-bottom: 5px;
}

/* 二级工具列表样式 - 核心修改：每行展示4个 */
.tool-list {
    display: grid; /* 改为grid布局实现每行4个 */
    grid-template-columns: repeat(4, 1fr); /* 固定每行4列 */
    gap: 10px 15px; /* 行列间距：上下10px，左右15px */
    padding: 5px 0;
}

.tool-item {
    font-size: 15px; /* 微调字号适配多列布局 */
    color: #222;
    padding: 12px 10px;
    border-radius: 6px;
    transition: all 0.2s ease;
    cursor: pointer;
    position: relative;
    padding-left: 20px;
    text-align: left;
    background-color: #fff;
    border: 1px solid #f0f0f0;
}

.tool-item:before {
    content: "";
    position: absolute;
    left: 8px;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 4px;
    background-color: #c00;
    border-radius: 50%;
}

.tool-item:hover {
    background-color: #f0f0f0;
    color: #c00;
    padding-left: 25px;
    border-color: #e0e0e0;
}

.tool-item.active {
    background-color: #fff0f0;
    color: #c00;
    font-weight: 500;
    border-left: 2px solid #c00;
    border-color: #ffeeee;
}

/* 工具描述信息 - 优化单列布局的视觉层次 */
.tool-description {
    margin-top: 40px;
    padding: 20px;
    border-radius: 8px;
    background-color: #f5f5f5;
    border-top: 2px solid #f0f0f0;
}

.description-title {
    font-size: 18px;
    font-weight: 600;
    color: #333;
    margin-bottom: 15px;
}

.description-content {
    font-size: 16px;
    color: #666;
    line-height: 1.8;
}

.description-highlight {
    color: #c00;
    font-weight: 500;
}

/* 响应式适配 - 优化每行4个布局的移动端展示 */
@media (max-width: 992px) {
    .tool-list {
        grid-template-columns: repeat(3, 1fr); /* 中等屏幕每行3个 */
    }
}

@media (max-width: 768px) {
    .top-nav {
        display: none;
    }
    .main-nav {
        top: 0px;
    }
    

    .main-nav .container {
        flex-direction: column;
        gap: 10px;
        padding: 10px 0;
    }

    .nav-menu {
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
        margin: 10px 0;
    }
    

    .tool-map-card {
        padding: 20px;
    }

    .tool-title {
        font-size: 20px;
    }

    .tool-category {
        padding: 10px;
    }

    .category-title {
        font-size: 17px;
    }

    .tool-list {
        grid-template-columns: repeat(2, 1fr); /* 移动端每行2个 */
    }
    .tool-item {
        font-size: 14px;
        padding: 10px 30px;
    }
}

@media (max-width: 480px) {
    .tool-list {
        grid-template-columns: 1fr; /* 小屏手机单行1个 */
    }
}