/* 全局样式和变量 */
:root {
    --primary-color: #5B6AFF; /* 蓝紫色 */
    --secondary-color: #8C54FF; /* 紫色 */
    --light-bg: #FFFFFF;
    --grey-bg: #F5F7FA;
    --dark-text: #333333;
    --medium-text: #666666;
    --light-text: #FFFFFF;
    --border-color: #E0E0E0;
    --shadow-color: rgba(0, 0, 0, 0.08);
    --border-radius: 12px;
    --spacing-unit: 8px;
    --font-family: 'Roboto', '思源黑体', sans-serif;
    --gradient: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
}

/* 暗色模式变量 */
body.dark-mode {
    --light-bg: #1a1a2e; /* 深蓝背景 */
    --grey-bg: #2a2a3e; /* 稍浅背景 */
    --dark-text: #E0E0E0; /* 浅灰文字 */
    --medium-text: #A0A0A0; /* 中灰文字 */
    --border-color: #40405a;
    --shadow-color: rgba(255, 255, 255, 0.1);
}

/* 基本重置和字体 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    background-color: var(--grey-bg);
    color: var(--dark-text);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* 顶部导航栏 */
.top-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: calc(var(--spacing-unit) * 8); /* 64px */
    background-color: var(--light-bg);
    display: flex;
    align-items: center;
    justify-content: space-between; /* logo | search | right-group */
    padding: 0 calc(var(--spacing-unit) * 3); /* 24px */
    box-shadow: 0 2px 8px var(--shadow-color);
    z-index: 1000;
    transition: background-color 0.3s ease;
}

.top-nav .logo {
    /* font-size, font-weight, color removed as logo is now an image */
    display: flex;
    align-items: center;
    /* color: var(--primary-color); */ /* Removed */
}

.top-nav .logo i {
    margin-right: var(--spacing-unit); /* 8px */
}

.top-nav .logo .logo-img {
    height: calc(var(--spacing-unit) * 4.5); /* 36px, adjust as needed */
    width: auto; /* Maintain aspect ratio */
    vertical-align: middle; /* Align image nicely */
}
/* New container for right-aligned elements in top-nav */
.top-nav-right {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 3); /* Space between tabs and actions */
}

.search-bar {
    /* Add margin auto for centering, or adjust flex properties on top-nav */
    /* Let's try adjusting flex grow on items */
    flex-grow: 1; /* Allow search to take space */
    margin: 0 calc(var(--spacing-unit) * 4); /* Add some margin around search */
    max-width: 500px; /* Optional: Limit search bar width */
    display: flex;
    align-items: center;
    background-color: var(--grey-bg);
    border-radius: calc(var(--border-radius) / 2); /* 6px */
    padding: calc(var(--spacing-unit) * 0.5) var(--spacing-unit); /* 4px 8px */
    transition: background-color 0.3s ease;
}

.search-bar input {
    border: none;
    outline: none;
    background: transparent;
    padding: calc(var(--spacing-unit) * 0.5) var(--spacing-unit); /* 4px 8px */
    color: var(--dark-text);
    min-width: 250px;
}

.search-bar button {
    background: none;
    border: none;
    color: var(--medium-text);
    cursor: pointer;
    padding: calc(var(--spacing-unit) * 0.5); /* 4px */
}

.top-nav .logo {
    flex-shrink: 0; /* Prevent logo from shrinking */
}
.top-nav-right {
     flex-shrink: 0; /* Prevent right group from shrinking */
}


.nav-actions {
    display: flex;
    align-items: center;
    gap: calc(var(--spacing-unit) * 2); /* 16px */
}

.nav-actions button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.2rem; /* ~19px */
    color: var(--medium-text);
    transition: color 0.2s ease;
}

.nav-actions button:hover {
    color: var(--primary-color);
}

.user-profile {
    display: flex;
    align-items: center;
    gap: var(--spacing-unit); /* 8px */
    cursor: pointer;
}

.user-profile i {
    font-size: 1.5rem; /* 24px */
    color: var(--medium-text);
}

.user-profile span {
    font-size: 0.9rem; /* ~14px */
    color: var(--medium-text);
}

/* 主容器和布局 */
.main-container {
    display: flex;
    padding-top: calc(var(--spacing-unit) * 8); /* 64px - top nav height */
}

/* 左侧导航 */
.side-nav {
    width: 240px;
    height: calc(100vh - var(--spacing-unit) * 8); /* Full height minus top nav */
    background-color: var(--light-bg);
    padding: calc(var(--spacing-unit) * 3) calc(var(--spacing-unit) * 2); /* 24px 16px */
    position: fixed;
    left: 0;
    top: calc(var(--spacing-unit) * 8);
    overflow-y: auto;
    box-shadow: 2px 0 8px var(--shadow-color);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.side-nav nav ul {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-unit); /* 8px */
}

.side-nav .category-item > a {
    display: flex;
    align-items: center;
    padding: calc(var(--spacing-unit) * 1.5) var(--spacing-unit); /* 12px 8px */
    border-radius: calc(var(--border-radius) / 2); /* 6px */
    transition: background-color 0.2s ease, color 0.2s ease;
    font-weight: 500;
    color: var(--medium-text);
}

.side-nav .category-item > a i:first-child {
    margin-right: calc(var(--spacing-unit) * 1.5); /* 12px */
    width: 20px; /* Ensure icons align */
    text-align: center;
}

.side-nav .category-item > a span {
    flex-grow: 1;
}

.side-nav .category-item > a .toggle-icon {
    font-size: 0.8rem;
    transition: transform 0.3s ease;
}

.side-nav .category-item.active > a {
    background-color: var(--primary-color);
    color: var(--light-text);
}

.side-nav .category-item.active > a .toggle-icon {
    transform: rotate(0deg); /* Keep down arrow as is */
}
.side-nav .category-item:not(.active) > a .toggle-icon.fa-chevron-down {
     transform: rotate(-90deg); /* Rotate right arrow */
}


.side-nav .category-item > a:hover {
    background-color: var(--grey-bg);
    color: var(--primary-color);
}
.side-nav .category-item.active > a:hover {
    background-color: var(--secondary-color); /* Slightly different hover for active */
    color: var(--light-text);
}


.side-nav .sub-menu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    padding-left: calc(var(--spacing-unit) * 4); /* 32px */
    margin-top: calc(var(--spacing-unit) * 0.5); /* 4px */
}

.side-nav .sub-menu.open {
    max-height: 500px; /* Adjust as needed */
}

.side-nav .sub-menu li a {
    display: block;
    padding: calc(var(--spacing-unit) * 1) 0; /* 8px 0 */
    font-size: 0.9rem; /* ~14px */
    color: var(--medium-text);
    transition: color 0.2s ease;
}

.side-nav .sub-menu li a:hover {
    color: var(--primary-color);
}

/* 主内容区 */
.content-area {
    flex-grow: 1;
    margin-left: 240px; /* side nav width */
    padding: calc(var(--spacing-unit) * 4); /* 32px */
    background-color: var(--grey-bg);
    min-height: calc(100vh - var(--spacing-unit) * 8);
    transition: background-color 0.3s ease;
}

.tool-category {
    margin-bottom: calc(var(--spacing-unit) * 5); /* 40px */
}

.tool-category h2 {
    font-size: 1.8rem; /* ~29px */
    margin-bottom: var(--spacing-unit); /* 8px */
    color: var(--dark-text);
    display: flex;
    align-items: center;
    gap: var(--spacing-unit);
}
.tool-category h2 i {
    color: var(--primary-color);
}


.tool-category p {
    font-size: 1rem; /* 16px */
    color: var(--medium-text);
    margin-bottom: calc(var(--spacing-unit) * 3); /* 24px */
}

/* 工具卡片网格 */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: calc(var(--spacing-unit) * 3); /* 24px */
}

/* 工具卡片 */
.tool-card {
    background-color: var(--light-bg);
    border-radius: var(--border-radius);
    padding: calc(var(--spacing-unit) * 3); /* 24px */
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: flex-start; /* Align items to the start */
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px var(--shadow-color);
}

.card-icon {
    font-size: 2rem; /* 32px */
    color: var(--primary-color);
    margin-bottom: calc(var(--spacing-unit) * 2); /* 16px */
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, rgba(91, 106, 255, 0.1), rgba(140, 84, 255, 0.1));
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}


.tool-card h3 {
    font-size: 1.2rem; /* ~19px */
    font-weight: 700;
    margin-bottom: var(--spacing-unit); /* 8px */
    color: var(--dark-text);
}

.tool-card p {
    font-size: 0.9rem; /* ~14px */
    color: var(--medium-text);
    margin-bottom: calc(var(--spacing-unit) * 2); /* 16px */
    flex-grow: 1; /* Make description take available space */
}

.use-button {
    background: var(--gradient);
    color: var(--light-text);
    border: none;
    padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 2.5); /* 10px 20px */
    border-radius: calc(var(--border-radius) / 2); /* 6px */
    cursor: pointer;
    font-weight: 500;
    transition: background 0.3s ease, transform 0.2s ease;
    align-self: flex-start; /* Align button to the start */
}

.use-button:hover {
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color)); /* Slightly darker gradient */
    transform: scale(1.05);
}

/* 响应式设计 */
@media (max-width: 992px) {
    .side-nav {
        width: 200px;
    }
    .content-area {
        margin-left: 200px;
        padding: calc(var(--spacing-unit) * 3); /* 24px */
    }
    .tool-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }
}

@media (max-width: 768px) {
    .top-nav {
        padding: 0 calc(var(--spacing-unit) * 2); /* 16px */
    }
    .search-bar input {
        min-width: 150px;
    }
    .side-nav {
        /* Example: Hide side nav and use a toggle button in top nav */
        /* For simplicity, let's just make it narrower for now */
         width: 60px; /* Collapse to icons only */
         padding: calc(var(--spacing-unit) * 2) var(--spacing-unit); /* 16px 8px */
    }
     .side-nav .category-item > a span,
     .side-nav .category-item > a .toggle-icon,
     .side-nav .sub-menu {
         display: none; /* Hide text and submenus */
     }
     .side-nav .category-item > a i:first-child {
         margin-right: 0;
     }
     .side-nav:hover { /* Expand on hover */
         width: 200px;
     }
     .side-nav:hover .category-item > a span,
     .side-nav:hover .category-item > a .toggle-icon {
         display: inline-block; /* Show text on hover */
     }
     .side-nav:hover .category-item > a i:first-child {
         margin-right: calc(var(--spacing-unit) * 1.5); /* 12px */
     }
     /* Submenu display on hover needs JS or more complex CSS */


    .content-area {
        margin-left: 60px; /* Adjust margin for collapsed nav */
        padding: calc(var(--spacing-unit) * 2); /* 16px */
    }
    .tool-grid {
        grid-template-columns: 1fr; /* Stack cards on smaller screens */
    }
    .tool-category h2 {
        font-size: 1.5rem; /* ~24px */
    }
}

@media (max-width: 576px) {
    .top-nav {
        height: auto;
        flex-direction: column;
        align-items: flex-start;
        padding: var(--spacing-unit) * 1.5; /* 12px */
    }
    .search-bar {
        width: 100%;
        margin: var(--spacing-unit) 0; /* 8px */
    }
    .search-bar input {
        width: 100%;
    }
    .nav-actions {
        width: 100%;
        justify-content: space-between;
    }
    .main-container {
        padding-top: calc(var(--spacing-unit) * 15); /* Adjust based on new top nav height */
    }
     .side-nav {
         /* Consider a hamburger menu approach for very small screens */
         /* For now, keep it collapsed */
         width: 50px;
         padding: var(--spacing-unit);
     }
     .content-area {
         margin-left: 50px;
         padding: var(--spacing-unit); /* 8px */
     }
}

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}
/* 悬浮微信图标 */
.floating-weixin {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #7bb32e, #09b63d); /* 微信绿色渐变 */
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    z-index: 1001; /* 确保在大多数内容之上 */
    transition: transform 0.3s ease;
}

.floating-weixin:hover {
    transform: scale(1.1);
}

/* 微信弹框 */
.weixin-modal {
    display: none; /* 默认隐藏 */
    position: fixed;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6); /* 半透明背景 */
    z-index: 1002; /* 在悬浮图标之上 */
    align-items: center;
    justify-content: center;
}

.weixin-modal.show {
    display: flex; /* 激活时显示 */
}

.modal-content {
    background-color: var(--light-bg);
    padding: 30px;
    border-radius: var(--border-radius);
    text-align: center;
    position: relative;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    max-width: 300px; /* 限制弹框宽度 */
    transition: background-color 0.3s ease;
}

.modal-content img {
    max-width: 200px; /* 调整二维码大小 */
    height: auto;
    display: block;
    margin: 15px auto;
}

.modal-content p {
    margin-top: 15px;
    color: var(--medium-text);
    font-size: 0.9rem;
}

.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    font-size: 28px;
    font-weight: bold;
    color: var(--medium-text);
    cursor: pointer;
    transition: color 0.2s ease;
}

.close-btn:hover {
    color: var(--dark-text);
}
/* Landing Page Tab Styles */
.landing-container {
    padding: 20px;
    margin-left: 0; /* Override content-area margin if side-nav is not present */
    margin-top: calc(var(--spacing-unit) * 8 + var(--spacing-unit) * 2); /* Adjust top margin for single top-nav height + padding */
    background-color: var(--grey-bg);
    min-height: calc(100vh - var(--spacing-unit) * 8); /* Adjust based on actual top-nav height */
}

.tab-nav {
    display: flex;
    /* Remove styles related to being a separate bar */
    /* border-bottom: 2px solid var(--border-color); */
    /* margin-bottom: calc(var(--spacing-unit) * 3); */
    height: 100%; /* Align with top-nav height */
    align-items: center;
}

.tab-button {
    padding: calc(var(--spacing-unit) * 1.5) calc(var(--spacing-unit) * 3); /* 12px 24px */
    cursor: pointer;
    border: none;
    background-color: transparent;
    font-size: 1rem; /* 16px */
    font-weight: 500;
    color: var(--medium-text);
    margin-right: var(--spacing-unit); /* 8px */
    border-bottom: 3px solid transparent;
    transition: border-color 0.3s ease, color 0.3s ease;
    /* margin-bottom: -2px; */ /* Remove alignment for old border */
    height: 100%; /* Fill top-nav height */
    display: flex; /* Align text vertically */
    align-items: center;
    padding: 0 calc(var(--spacing-unit) * 2); /* Adjust padding */
}

.tab-button:hover {
    color: var(--dark-text);
}

.tab-button.active {
    border-bottom-color: var(--primary-color);
    color: var(--primary-color);
    font-weight: 700;
}

.tab-content {
    display: none;
    padding: calc(var(--spacing-unit) * 2) 0; /* 16px 0 */
    animation: fadeIn 0.5s ease; /* Add a fade-in effect */
}

.tab-content.active {
    display: block;
}

.tab-content h2 {
    font-size: 1.6rem; /* ~26px */
    color: var(--dark-text);
    margin-bottom: calc(var(--spacing-unit) * 2); /* 16px */
}

.tab-content p {
    color: var(--medium-text);
    line-height: 1.7;
}

/* Simple fade-in animation */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Responsive adjustments for landing page if needed */
@media (max-width: 768px) {
    .landing-container {
        margin-top: calc(var(--spacing-unit) * 8); /* Adjust if top nav changes height */
        padding: 15px;
    }
    .tab-button {
        padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 2); /* 10px 16px */
        font-size: 0.9rem;
    }
}

@media (max-width: 576px) {
     .landing-container {
        /* Adjust based on stacked top nav height */
        margin-top: calc(var(--spacing-unit) * 16);
        padding: 10px;
    }
    .tab-nav {
        /* Could make tabs scrollable horizontally if too many */
        overflow-x: auto;
        white-space: nowrap;
    }
     .tab-button {
        padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5); /* 8px 12px */
    }
}
/* Landing Page - Tools Tab Layout */
.tab-content#tools.active {
    display: flex;
    padding: 0; /* Remove default tab content padding */
    /* Ensure it takes up available space if needed, might not be necessary */
}

/* Side Nav within Tools Tab */
.tab-content#tools .side-nav {
    position: sticky; /* Make it stick within the scrolling container */
    /* Adjust top based on single top-nav height */
    top: calc(var(--spacing-unit) * 8); /* 64px */
    height: calc(100vh - var(--spacing-unit) * 8); /* Adjust height */
    box-shadow: none; /* Remove fixed shadow, maybe add a right border */
    border-right: 1px solid var(--border-color);
    flex-shrink: 0; /* Prevent side-nav from shrinking */
    /* Override fixed position styles */
    left: auto;
    z-index: 1; /* Ensure it's above content but below headers */
}

/* Content Area within Tools Tab */
.tab-content#tools .content-area {
    /* margin-left: 240px; */ /* Already defined globally, should work */
    padding: calc(var(--spacing-unit) * 3); /* Add padding back */
    min-height: auto; /* Override default min-height */
    background-color: transparent; /* Inherit from landing-container */
    width: 100%; /* Ensure it takes remaining width */
}
.tab-content#tools .content-area h2:first-of-type {
    /* Hide the duplicate "工具集" h2 inside the content area */
    display: none;
}


/* Responsive adjustments for Tools Tab Layout */
@media (max-width: 992px) {
    .tab-content#tools .content-area {
        margin-left: 200px; /* Match side-nav width */
        padding: calc(var(--spacing-unit) * 2.5);
    }
}

@media (max-width: 768px) {
     .tab-content#tools.active {
        /* Keep flex layout even when side-nav collapses */
     }
    .tab-content#tools .side-nav {
        /* Styles for collapsed side-nav are already defined globally */
        /* Adjust sticky top position if header heights change */
         /* Adjust sticky top position if header heights change in responsive */
         top: calc(var(--spacing-unit) * 8); /* Assuming top-nav height remains 64px */
         height: calc(100vh - var(--spacing-unit) * 8);
    }
    .tab-content#tools .content-area {
        margin-left: 60px; /* Match collapsed side-nav width */
        padding: calc(var(--spacing-unit) * 2);
    }
     .tab-content#tools .side-nav:hover .content-area {
         /* This interaction might be complex - maybe push content? */
         /* For now, content margin remains based on collapsed width */
     }
}

@media (max-width: 576px) {
    .tab-content#tools.active {
        /* Stack side-nav and content? Or keep flex? Keep flex for now. */
    }
     .tab-content#tools .side-nav {
        /* Styles for collapsed side-nav */
         /* Adjust based on stacked top nav height */
         top: calc(var(--spacing-unit) * 15); /* Example: if top-nav becomes 120px */
         height: calc(100vh - var(--spacing-unit) * 15);
    }
    .tab-content#tools .content-area {
        margin-left: 50px; /* Match collapsed side-nav width */
        padding: var(--spacing-unit);
    }
}