/* 全局重置 */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 页面主体 */
body {
    font-family: "Microsoft YaHei", "PingFang SC", -apple-system, BlinkMacSystemFont, sans-serif;
    color: #333;
    line-height: 1.6;
    padding-top: 62px;
}

/* ========== 页头 / 导航（共享 site-header） ========== */
#site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
}

/* 菜单加载失败时的降级提示（由 components.js 渲染） */
.site-header-error {
    background: #fff3cd;
    border-bottom: 1px solid #ffc107;
    color: #856404;
    padding: 10px 16px;
    text-align: center;
    font-size: 14px;
}
.site-header-load-error {
    min-height: 48px;
}

.site-header {
    background-color: #1a1a2e;
    padding: 15px 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

/* 旧式 .header 别名 —— 仍使用 <header class="header"> 的页面在迁移前获得相同样式。 */
.header {
    background-color: #1a1a2e;
    padding: 15px 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

/* Logo 图标 */
.logo {
    color: #fff;
    font-size: 20px;
    font-weight: bold;
    letter-spacing: 1px;
    text-decoration: none;
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: color 0.3s ease, transform 0.3s ease;
}

.logo:hover {
    color: #f0a500;
    transform: translateY(-1px);
}

.logo-badge {
    display: inline-block;
    font-size: 9px;
    font-weight: 500;
    letter-spacing: 0.5px;
    padding: 2px 6px;
    border: 1px solid currentColor;
    border-radius: 4px;
    opacity: 0.85;
    line-height: 1.4;
    white-space: nowrap;
}

/* Hero 标题（42px h1）需要更大的徽章以保持比例 */
.vp-hero-title .logo-badge {
    font-size: 14px;
    padding: 4px 12px;
    border-width: 1.5px;
    border-radius: 6px;
    vertical-align: middle;
    margin-left: 4px;
}

/* 导航 */
.site-nav,
.nav {
    display: flex;
    align-items: center;
    gap: 24px;
}

.site-nav a,
.nav a {
    color: #ccc;
    text-decoration: none;
    font-size: 15px;
    transition: color 0.3s;
    position: relative;
    padding-bottom: 3px;
}

/* 悬停 / 激活时从中央向外生长的动画下划线。 */
.site-nav a::after,
.nav a::after {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 2px;
    background-color: #4a90d9;
    transform: scaleX(0);
    transform-origin: center;
    transition: transform 0.3s cubic-bezier(0.2, 0.7, 0.2, 1);
}

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

.site-nav a:hover::after,
.nav a:hover::after {
    transform: scaleX(1);
}

.site-nav a.active,
.nav a.active {
    color: #fff;
    border-bottom: 2px solid #4a90d9;
    padding-bottom: 3px;
}

.site-nav a.active::after,
.nav a.active::after {
    transform: scaleX(1);
    background-color: #4a90d9;
}

.site-nav .tool-link,
.nav .tool-link {
    color: #f0a500;
}

/* ========== 下拉菜单分组（下载与反馈 等） ========== */
.nav-group {
    position: relative;
}

.nav-group-trigger {
    background: transparent;
    border: none;
    color: #ccc;
    font-family: inherit;
    font-size: 15px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 0;
    transition: color 0.3s;
}

.nav-group-trigger:hover,
.nav-group-trigger:focus {
    color: #fff;
    outline: none;
}

.nav-group-trigger .caret {
    font-size: 10px;
    transition: transform 0.2s;
}

.nav-group.open .nav-group-trigger .caret {
    transform: rotate(180deg);
}

.nav-group-menu {
    position: absolute;
    top: calc(100% + 12px);
    left: -12px;
    min-width: 180px;
    background-color: #1a1a2e;
    border: 1px solid #30363d;
    border-radius: 8px;
    padding: 8px 0;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: opacity 0.18s, transform 0.18s, visibility 0.18s;
    z-index: 1100;
}

.nav-group.open .nav-group-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav-group-menu a {
    display: block;
    padding: 10px 18px;
    font-size: 14px;
    color: #ccc;
    text-decoration: none;
    transition: background-color 0.15s, color 0.15s;
}

.nav-group-menu a:hover,
.nav-group-menu a:focus {
    background-color: rgba(255, 255, 255, 0.08);
    color: #fff;
}

/* 语言切换器 */
.lang-switcher {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 2px;
}

.lang-switcher a,
.lang-switcher .lang {
    color: #888;
    font-size: 14px;
    text-decoration: none;
    cursor: pointer;
    transition: color 0.2s;
}

.lang-switcher a:hover,
.lang-switcher .lang:hover {
    color: #fff;
}

.lang-switcher a.active,
.lang-switcher .lang.active {
    color: #fff;
}

.lang-switcher .lang-divider {
    color: #444;
    font-size: 14px;
}

/* ========== 汉堡菜单开关（仅移动端） ========== */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    cursor: pointer;
    gap: 5px;
    background: transparent;
    border: none;
    padding: 0;
    border-radius: 8px;
    transition: background-color 0.25s ease, transform 0.2s ease;
}

.nav-toggle:hover {
    background-color: rgba(255, 255, 255, 0.08);
}

.nav-toggle:active {
    transform: scale(0.92);
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: #fff;
    transition: all 0.3s;
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ========== 浮动操作按钮（成对设计） ==========
   .menu-toggle（指南页左下）与 .back-to-top（所有页面右下）共用同一套样式。
   两者都是正圆，尺寸、阴影、悬停效果、层级一致 —— 让视口两角的按钮读作一对
   协调的设计，而不是恰好出现在同一块屏幕上的两个无关按钮。

   下方每个按钮的覆盖样式只处理真正不同的部分：位置（左 / 右）、
   生命周期（始终可见 / 滚动触发）以及图标。 */
.menu-toggle,
.back-to-top {
    position: fixed;
    width: 52px;
    height: 52px;
    bottom: 24px;
    padding: 0;
    background-color: #4a90d9;
    color: #fff;
    border: none;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 1003;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
    transition: background-color 0.25s ease,
                transform 0.25s cubic-bezier(0.2, 0.7, 0.2, 1),
                box-shadow 0.25s ease;
    font-family: inherit;
    user-select: none;
}

/* 每个按钮的位置 + 生命周期 */
.menu-toggle {
    left: 24px;
    /* Pop in 动画：仅在侧栏抽屉挂载时播放一次（指南页）。 */
    animation: anim-pop-in 0.5s cubic-bezier(0.2, 0.8, 0.3, 1.4) 0.4s both;
}

.back-to-top {
    right: 24px;
    /* 用户滚动超过 100px 前一直隐藏；JS 切换 .show 类。 */
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s,
                background-color 0.25s ease,
                transform 0.25s cubic-bezier(0.2, 0.7, 0.2, 1),
                box-shadow 0.25s ease;
}

/* menu-toggle 仅在移动端作为抽屉触发器 —— 桌面端隐藏。
   mobile.css 在 @media (max-width: 768px) 内重新启用它。 */
.menu-toggle {
    display: none;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    /* 每次按钮重新出现时重播 pop-in 动画。 */
    animation: anim-pop-in 0.5s cubic-bezier(0.2, 0.8, 0.3, 1.4) both;
}

.menu-toggle:hover,
.back-to-top:hover {
    background-color: #357abd;
    transform: scale(1.08);
    box-shadow: 0 8px 22px rgba(74, 144, 217, 0.5);
}

.menu-toggle:active,
.back-to-top:active {
    transform: scale(0.94);
}

/* 汉堡图标在 .menu-toggle 内。<span> 是中间一条；::before / ::after 绘制上下两条。 */
.menu-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background-color: #fff;
    position: relative;
    transition: background-color 0.3s;
}

.menu-toggle span::before,
.menu-toggle span::after {
    content: '';
    position: absolute;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: #fff;
    transition: transform 0.3s;
}

.menu-toggle span::before { top: -7px; }
.menu-toggle span::after  { bottom: -7px; }

/* .back-to-top 内的向上箭头。粗细匹配 menu-toggle 的 22px 图标，
   同样填充白色 —— 让两个按钮读作兄弟按钮，而非"圆形按钮 vs 胶囊按钮"。 */
.back-to-top svg {
    width: 22px;
    height: 22px;
    fill: #fff;
    display: block;
}

/* "顶部" 文字标签被隐藏，让按钮保持与 menu-toggle 一样的简洁圆形。
   向上箭头 SVG 已被普遍认知；标签仍保留在 DOM 中供屏幕阅读器读取
   （display:none 仍然暴露文本节点）。 */
.back-to-top-label {
    display: none;
}

/* ========== 响应式（通用） ========== */

/* 平板 */
@media (max-width: 1024px) {
    .site-header,
    .header {
        padding: 15px 30px;
    }

    .site-nav,
    .nav {
        gap: 18px;
    }
}

/* 手机 */
@media (max-width: 768px) {
    body {
        padding-top: 56px;
    }

    .site-header,
    .header {
        padding: 12px 18px;
        position: relative;
        flex-wrap: wrap;
    }

    .logo {
        font-size: 17px;
    }

    .site-nav,
    .nav {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        gap: 0;
        background-color: #1a1a2e;
        padding: 0 24px;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.4s ease, padding 0.4s ease;
        box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
        z-index: 1000;
    }

    .site-nav.open,
    .nav.open {
        padding: 12px 24px 20px;
        max-height: 70vh;
        overflow-y: auto;
    }

    .site-nav a,
    .nav a {
        padding: 12px 8px;
        text-align: left;
        border-bottom: 1px solid rgba(255, 255, 255, 0.08);
        width: auto;
        min-width: 0;
    }

    .site-nav a.active,
    .nav a.active {
        border-bottom: 1px solid #4a90d9;
        border-bottom-width: 1px;
    }

    /* 下拉菜单 —— 在移动端抽屉里渲染为内联列表 */
    .nav-group {
        width: 100%;
    }

    .nav-group-trigger {
        width: 100%;
        padding: 12px 8px;
        justify-content: space-between;
        border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }

    .nav-group-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        background-color: rgba(0, 0, 0, 0.25);
        border: none;
        border-radius: 0;
        box-shadow: none;
        padding: 4px 0 8px 12px;
        min-width: 0;
        display: none;
    }

    .nav-group.open .nav-group-menu {
        display: block;
    }

    .lang-switcher {
        order: -1;
        margin-left: 0;
        margin-bottom: 8px;
        padding: 8px;
    }

    .nav-toggle {
        display: flex;
    }
}

/* 小屏手机 */
@media (max-width: 480px) {
    .site-header,
    .header {
        padding: 10px 16px;
    }

    .logo {
        font-size: 16px;
    }
}

/* ============================================================
   § 动画库 —— 共享关键帧 + 工具类
   通过 common.css 在每个页面加载。提供入场动画、微交互，
   以及严格的 `prefers-reduced-motion` 关闭选项。
   ============================================================ */

/* --- 关键帧 --- */
@keyframes anim-fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes anim-fade-up {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes anim-fade-down {
  from { opacity: 0; transform: translateY(-14px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes anim-fade-left {
  from { opacity: 0; transform: translateX(-14px); }
  to   { opacity: 1; transform: translateX(0); }
}

@keyframes anim-fade-right {
  from { opacity: 0; transform: translateX(14px); }
  to   { opacity: 1; transform: translateX(0); }
}

@keyframes anim-pop-in {
  0%   { opacity: 0; transform: scale(0.86); }
  60%  { opacity: 1; transform: scale(1.04); }
  100% { opacity: 1; transform: scale(1); }
}

@keyframes anim-float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-4px); }
}

@keyframes anim-soft-float {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  33%      { transform: translateY(-3px) rotate(0.4deg); }
  66%      { transform: translateY(2px)  rotate(-0.4deg); }
}

@keyframes anim-bounce-soft {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-6px); }
}

@keyframes anim-icon-bob {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-2px); }
}

@keyframes anim-underline-grow {
  from { transform: translateX(-50%) scaleX(0); }
  to   { transform: translateX(-50%) scaleX(1); }
}

@keyframes anim-shine-sweep {
  0%   { transform: translateX(-160%) skewX(-18deg); }
  100% { transform: translateX(260%) skewX(-18deg); }
}

@keyframes anim-shimmer {
  0%   { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

@keyframes anim-pulse-ring {
  0%   { box-shadow: 0 0 0 0 currentColor; }
  70%  { box-shadow: 0 0 0 10px transparent; }
  100% { box-shadow: 0 0 0 0 transparent; }
}

@keyframes anim-gradient-pan {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

@keyframes anim-pop {
  0%   { transform: scale(1); }
  40%  { transform: scale(1.15); }
  100% { transform: scale(1); }
}

@keyframes anim-blink {
  0%, 50%      { opacity: 1; }
  50.01%, 100% { opacity: 0; }
}

/* --- 入场工具类 --- */
.anim-fade-in       { animation: anim-fade-in   0.6s ease both; }
.anim-fade-up       { animation: anim-fade-up   0.6s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
.anim-fade-down     { animation: anim-fade-down 0.6s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
.anim-fade-left     { animation: anim-fade-left 0.6s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
.anim-fade-right    { animation: anim-fade-right 0.6s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
.anim-pop-in        { animation: anim-pop-in    0.5s cubic-bezier(0.2, 0.8, 0.3, 1.4) both; }

/* Stagger —— 应用在容器上，子元素依次入场。 */
.anim-stagger > * { animation: anim-fade-up 0.55s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
.anim-stagger > *:nth-child(1) { animation-delay: 0.05s; }
.anim-stagger > *:nth-child(2) { animation-delay: 0.12s; }
.anim-stagger > *:nth-child(3) { animation-delay: 0.19s; }
.anim-stagger > *:nth-child(4) { animation-delay: 0.26s; }
.anim-stagger > *:nth-child(5) { animation-delay: 0.33s; }
.anim-stagger > *:nth-child(6) { animation-delay: 0.40s; }
.anim-stagger > *:nth-child(7) { animation-delay: 0.47s; }
.anim-stagger > *:nth-child(8) { animation-delay: 0.54s; }
.anim-stagger > *:nth-child(n+9) { animation-delay: 0.60s; }

/* 按钮 / 链接 / 卡片的悬停按下微交互。 */
.tap-feedback        { transition: transform 0.12s ease, box-shadow 0.2s ease; }
.tap-feedback:active { transform: scale(0.97); }

/* --- 减弱动效：全局尊重该设置 ---
   装饰性动画被关闭；功能性状态变化（可见性 / 颜色）仍然生效，
   只是瞬间切换。 */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .anim-stagger > * { animation-delay: 0s !important; }
}