/*
 * Material You 优化后的颜色变量 (基于 #1a73e8)
 */
:root {
    /* Primary Color: #1a73e8 (原始主色调) */
    --primary: #1a73e8;
    --on-primary: #ffffff;
    --primary-container: #d3e3fd; /* 选中状态的背景色 */
    --on-primary-container: #001d3d;
    /* Secondary Color & Surface */
    --secondary: #585e71;
    --on-secondary: #ffffff;
    --secondary-container: #e1e2ec;
    --on-secondary-container: #1b1b1f;
    --surface: #fefbff;
    --on-surface: #1b1b1f;
    --surface-variant: #e1e2ec;
    --on-surface-variant: #45464f;
    /* Outline and Accent */
    --outline: #757780;
    --outline-variant: #c5c6d0;
    /* 交互专用色 */
    --hover-overlay: rgba(26, 115, 232, 0.08); /* 悬浮时的透明主色叠加 */
    --highlight-color: #63a4ff; /* 提亮/激活色 */
    --highlight-container: #bbdefb; /* 醒目高亮的背景色 (用于焦点环背景) */
    /* 尺寸和字体 */
    --corner-radius: 16px; /* 大圆角 */
    --small-radius: 8px; /* 列表项和输入框圆角 */
    --font-family: 'Roboto', 'Segoe UI', system-ui, sans-serif;
}
/* 🎯 核心解决：禁用所有浏览器自带的点击和焦点高亮 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    /* 解决触屏点击蓝色背景高亮 */
    -webkit-tap-highlight-color: transparent; 
    /* 解决某些浏览器默认的焦点阴影 */
    -webkit-box-shadow: none !important; 
    box-shadow: none !important;
}
/* 💎 可访问性：移除所有元素的默认焦点轮廓，由 :focus-visible 接管 */
*:focus {
    outline: none;
    /* 确保鼠标点击时不保留任何焦点样式 */
    box-shadow: none; 
}
body {
    font-family: var(--font-family);
    background-color: var(--surface);
    color: var(--on-surface);
    line-height: 1.5;
    padding: 16px;
    max-width: 800px;
    margin: 0 auto;
    /* 防止移动端键盘弹出时body高度变化 */
    min-height: 100vh;
    overflow-x: hidden;
}
h1 {
    color: var(--primary);
    margin: 20px 0;
    text-align: center;
    font-weight: 500;
    font-size: 2rem;
}
/* --- ## 单元标题 (Unit-Title) --- */
/* 移除整个单元标题样式 */
.unit-title {
    display: none;
}
.unit-section {
    margin-bottom: 24px;
    display: none; /* 默认隐藏 */
}
.unit-section.active {
    display: block;
    animation: fadeIn 0.3s ease-in-out;
}
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}
/* --- ## 单词项目 (Word-Item) --- */
.word-item {
    margin: 8px 0;
    padding: 14px 20px;
    background-color: var(--surface);
    border: 1px solid var(--outline-variant);
    border-radius: var(--small-radius);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}
.word-item:hover {
    border-color: var(--outline-variant); /* 边框颜色不随悬停变化 */
    background-color: var(--hover-overlay); /* 悬浮效果：浅色透明叠加 */
    box-shadow: 0 2px 4px -1px rgba(0, 0, 0, 0.05);
}
.word-item:active {
    background-color: rgba(26, 115, 232, 0.15); /* Material You 按下效果 */
}
.word-item:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px var(--highlight-container), 0 0 0 5px var(--primary);
}
.selected {
    background-color: var(--primary-container);
    opacity: 1;
    border-color: var(--primary);
    box-shadow: 0 2px 4px -1px rgba(0, 0, 0, 0.1);
}
.selected:hover {
    border-color: var(--primary); /* 选中状态下悬停时保持蓝色边框 */
    background-color: var(--hover-overlay); /* 悬浮效果：浅色透明叠加 */
}
.word-table {
    width: 100%;
    border-collapse: collapse;
}
.word-cell {
    padding: 4px 0;
    vertical-align: middle;
}
.word-col {
    width: 50%; /* 英文和中文各占50% */
}
.detail-col {
    width: auto; /* [详]列自适应宽度 */
    min-width: 40px;
    text-align: center;
}
.hidden-content {
    color: transparent;
    user-select: none;
}
.selected .hidden-content {
    color: var(--on-surface);
}
/* --- ## 单元链接/切换按钮 (Unit-Link) --- */
.unit-link {
    display: inline-block;
    margin: 4px 8px 4px 0;
    padding: 8px 16px;
    cursor: pointer;
    color: var(--primary);
    background-color: var(--primary-container);
    border: none;
    border-radius: 999px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}
.unit-link:hover {
    background-color: #c5d9fc;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}
.unit-link:active {
    background-color: #a0c2f9;
}
.unit-link.active {
    background-color: var(--primary);
    color: var(--on-primary);
}
.unit-link.active:active {
    background-color: #0d62d9;
}
.unit-link:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px var(--highlight-container), 0 0 0 5px var(--primary);
}
/* --- ## 搜索框和选择器 (Input/Select) --- */
#searchBox, #bookSelect {
    margin: 8px 0; /* 减小间距 */
    padding: 10px 16px; /* 减小高度 */
    width: 100%;
    border: 1px solid var(--outline);
    border-radius: 999px; /* 更圆 */
    background-color: var(--surface);
    color: var(--on-surface);
    font-size: 1rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    -webkit-box-shadow: none;
    box-shadow: none;
}
#searchBox:focus, #bookSelect:focus {
    border-color: var(--primary);
    outline: none;
    box-shadow: 0 0 0 2px var(--primary);
}
#bookSelect {
    /* 自定义下拉箭头 (Material You 风格) */
    appearance: none;
    background-image: url('data:image/svg+xml;utf8,<svg fill="%2345464F" height="24" viewBox="0 0 24 24" width="24" xmlns="http://www.w3.org/2000/svg"><path d="M7 10l5 5 5-5z"/></svg>');
    background-repeat: no-repeat;
    background-position: right 12px top 50%;
    padding-right: 40px;
}
/* --- ## 切换容器/按钮 (Toggle Button) --- */
.toggle-container {
    position: fixed;
    top: 16px;
    right: 16px;
    z-index: 9999;
    display: flex;
    gap: 8px;
}
.toggle-btn {
    padding: 10px 14px;
    background: var(--surface-variant);
    color: var(--on-surface-variant);
    border: none;
    border-radius: 999px;
    cursor: pointer;
    font-size: 0.8rem;
    font-weight: 500;
    min-width: 50px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}
.toggle-btn:hover {
    background: #d5d6e0;
}
.toggle-btn:active {
    background: #c8c9d4;
}
.toggle-btn.active {
    background: var(--primary);
    color: var(--on-primary);
    box-shadow: 0 2px 4px -1px rgba(0, 0, 0, 0.1);
}
.toggle-btn.active:active {
    background: #0d62d9;
}
.toggle-btn:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px var(--highlight-container), 0 0 0 5px var(--primary);
}
#unitLinks {
    margin: 16px 0;
    display: flex;
    flex-wrap: wrap;
}
.checkbox-container {
    display: flex;
    align-items: center;
    margin-right: 12px;
}
input[type="checkbox"] {
    width: 20px;
    height: 20px;
    accent-color: var(--primary);
    border-radius: 6px;
    border: 2px solid var(--outline);
    transition: all 0.2s ease-in-out;
}
input[type="checkbox"]:focus-visible {
    outline: none;
    box-shadow: 0 0 0 2px var(--primary);
    border-radius: 6px;
}
/* --- ## 取消选择按钮 (旧版样式) --- */
.unit-unselect-btn, #unselectAllBtn {
    background-color: var(--surface-variant);
    color: var(--on-surface-variant);
    border: 1px solid var(--outline);
    border-radius: var(--corner-radius);
    padding: 6px 12px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: background-color 0.2s ease-in-out;
    position: relative;
}
.unit-unselect-btn:hover, #unselectAllBtn:hover {
    background-color: #d0d0d0;
}
.unit-unselect-btn:active, #unselectAllBtn:active {
    background-color: #c4c4c4;
    transform: translateY(1px);
}
/* 自定义按钮焦点效果 */
.unit-unselect-btn:focus-visible, #unselectAllBtn:focus-visible {
    outline: none;
    box-shadow: 0 0 0 2px var(--primary);
}
.part-of-speech {
    color: var(--outline);
    font-size: 0.9em;
    margin-right: 4px;
}
.search-results {
    margin: 16px 0;
    max-height: 600px;
    overflow-y: auto;
    border: 1px solid var(--outline-variant);
    border-radius: var(--corner-radius);
    display: none;
    animation: fadeIn 0.3s ease-in-out;
    /* 防止键盘弹出时被遮挡 */
    z-index: 1000;
    position: relative;
    background-color: var(--surface);
}
/* --- ## 搜索结果项 (Search-Result-Item) --- */
.search-result-item {
    padding: 14px 20px;
    border-bottom: 1px solid var(--outline-variant);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: var(--small-radius);
    margin: 4px;
    position: relative;
}
.search-result-item:last-child {
    border-bottom: none;
}
.search-result-item:hover {
    border-color: var(--outline-variant); /* 边框颜色不随悬停变化 */
    background-color: var(--hover-overlay); /* 悬浮效果：浅色透明叠加 */
}
.search-result-item:active {
    background-color: rgba(26, 115, 232, 0.15);
}
.search-result-item:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px var(--highlight-container), 0 0 0 5px var(--primary);
}
.search-result-book {
    font-size: 0.8rem;
    color: var(--outline);
    margin-top: 4px;
}
/* --- ## 💥 跳转高亮显示 (Highlight) --- */
.highlight {
    background-color: var(--highlight-container);
    border: 2px solid var(--highlight-color);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 0 8px rgba(99, 164, 255, 0.7) !important; 
    animation: none;
}
/* 移除所有点击效果相关的类 */
.clickable {
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
/* 新增：重置按钮和取消全选按钮在同一行 */
.reset-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 8px 0; /* 减小间距 */
}
.reset-controls .unit-unselect-btn {
    margin-left: 12px;
}
/* 发音按钮样式 */
.pronunciation-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    margin-left: 8px;
    opacity: 0.6;
    transition: opacity 0.2s;
    vertical-align: middle;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}
.pronunciation-btn:hover {
    opacity: 1;
}
.pronunciation-btn svg {
    width: 16px;
    height: 16px;
    fill: var(--on-surface-variant);
}
/* 详情按钮样式 - 独立成列 */
.detail-btn {
    background: none;
    border: 1px solid var(--outline-variant);
    cursor: pointer;
    padding: 4px 8px;
    opacity: 0.6;
    transition: opacity 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    color: var(--on-surface-variant);
    font-size: 0.8rem;
    text-decoration: none;
    border-radius: 4px;
    min-width: 40px;
}
.detail-btn:hover {
    opacity: 1;
    color: var(--primary);
    border-color: var(--primary);
}
/* 确保按钮大小一致 */
.detail-btn, .pronunciation-btn {
    height: 24px;
}