/* ============================================================
   全站设计 Token —— 改这里，全站生效
   ============================================================ */
:root {
    /* 品牌色 */
    --c-primary:        #1d6fe8;
    --c-primary-hover:  #0ea5e9;
    --c-primary-light:  #38bdf8;
    --c-primary-bg:     #e0f2fe;
    --c-primary-bg-2:   #eff6ff;

    /* 深色系 */
    --c-dark:           #0f2a4a;
    --c-dark-deep:      #0a1f3d;
    --c-dark-soft:      #1e3c72;
    --c-text:           #0f172a;
    --c-text-mid:       #334155;
    --c-text-soft:      #475569;
    --c-text-muted:     #64748b;
    --c-text-light:     #94a3b8;
    --c-text-faint:     #cbd5e1;

    /* 中性色 */
    --c-border:         #e2e8f0;
    --c-border-light:   #f1f5f9;
    --c-bg-soft:        #f8fafc;
    --c-bg-white:       #ffffff;

    /* 语义色 */
    --c-success:        #10b981;
    --c-danger:         #d32f2f;

    /* 圆角 */
    --radius-xs:        4px;
    --radius-sm:        6px;
    --radius-md:        8px;
    --radius-lg:        12px;
    --radius-xl:        16px;
    --radius-full:      999px;

    /* 动效 */
    --ease:             0.25s ease;
    --ease-fast:        0.15s ease;
    --ease-slow:        0.5s ease;

    /* 阴影 */
    --shadow-sm:        0 1px 3px rgba(15, 42, 74, 0.06);
    --shadow-md:        0 8px 24px rgba(15, 42, 74, 0.1);
    --shadow-lg:        0 20px 40px rgba(15, 42, 74, 0.15);
    --shadow-primary:   0 6px 20px rgba(29, 111, 232, 0.25);
}


/* ============================================================
   全站基础重置
   ============================================================ */
html, body {
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    /* 强制全站统一使用无衬线字体，彻底解决火狐浏览器衬线问题 */
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-size: 15px;
    line-height: 1.6;
    color: var(--c-text-mid);
    background-color: var(--c-bg-white);
}

*, *::before, *::after {
    box-sizing: inherit;
}

img {
    max-width: 100%;
    height: auto;
}


/* ============================================================
   返回顶部按钮（全站通用）
   ============================================================ */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: none;
    background: var(--c-primary);
    color: #fff;
    font-size: 22px;
    font-weight: bold;
    cursor: pointer;
    z-index: 999;
    display: none;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 20px -8px rgba(29, 111, 232, 0.5);
    transition: background var(--ease), transform var(--ease);
}
.back-to-top:hover {
    background: var(--c-primary-hover);
    transform: translateY(-3px);
}
@media (max-width: 700px) {
    .back-to-top {
        width: 42px;
        height: 42px;
        font-size: 18px;
        bottom: 20px;
        right: 20px;
    }
}


/* ============================================================
   侧边悬浮导航（全站通用）
   ============================================================ */

/* ---------- 桌面 / 平板：完整版 ---------- */
.side-nav {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 90;
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 12px 8px;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--c-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.35s ease;
}
.side-nav.visible { opacity: 1; pointer-events: auto; }

.side-nav-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 9px 14px;
    border-radius: var(--radius-md);
    color: var(--c-text-muted);
    text-decoration: none;
    font-size: 13px;
    font-weight: 600;
    white-space: nowrap;
    transition: background 0.2s, color 0.2s;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}
.side-nav-item:hover { background: var(--c-border-light); color: var(--c-dark); }
.side-nav-item.active { background: var(--c-primary-bg-2); color: var(--c-primary); }

.side-nav-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--c-text-faint);
    flex-shrink: 0;
    transition: background 0.25s, box-shadow 0.25s, transform 0.25s;
}
.side-nav-item.active .side-nav-dot {
    background: var(--c-primary);
    box-shadow: 0 0 0 4px rgba(29, 111, 232, 0.15);
}

/* 文字：默认一直显示 */
.side-nav-item .side-nav-text {
    display: inline-block;
    transition: color 0.25s ease, transform 0.25s ease;
}

/* 箭头：默认隐藏，激活时显示 */
.side-nav-arrow {
    opacity: 0;
    margin-left: auto;
    padding-left: 10px;
    font-size: 18px;
    line-height: 1;
    color: var(--c-primary);
    font-weight: 700;
    transition: opacity 0.25s ease, transform 0.25s ease;
    pointer-events: none;
}
.side-nav-item.active .side-nav-arrow {
    opacity: 1;
    animation: sideNavArrowPulse 1.8s ease-in-out infinite;
}
@keyframes sideNavArrowPulse {
    0%, 100% { transform: translateX(0); }
    50%      { transform: translateX(4px); }
}

/* 滚动切换段落时，文字"弹一下" */
.side-nav-item.pop .side-nav-text {
    color: var(--c-primary);
    font-weight: 800;
    transform: scale(1.08);
    transform-origin: left center;
    animation: sideNavTextPop 0.8s ease;
}
@keyframes sideNavTextPop {
    0%   { transform: scale(1);    color: var(--c-text-muted); }
    20%  { transform: scale(1.12); color: var(--c-primary); }
    60%  { transform: scale(1.08); color: var(--c-primary); }
    100% { transform: scale(1);    color: var(--c-text-muted); }
}

/* ---------- 子项（缩进 + 小圆点） ---------- */
.side-nav-item-child {
    padding-left: 28px;
    font-size: 12.5px;
    color: var(--c-text-light);
}
.side-nav-item-child .side-nav-dot {
    width: 6px;
    height: 6px;
}
.side-nav-item-child.active .side-nav-dot {
    box-shadow: 0 0 0 3px rgba(29, 111, 232, 0.15);
}

/* ---------- 遮罩层 ---------- */
.side-nav-overlay {
    position: fixed;
    inset: 0;
    background: rgba(10, 20, 35, 0.5);
    backdrop-filter: blur(2px);
    -webkit-backdrop-filter: blur(2px);
    z-index: 98;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease;
}
.side-nav-overlay.open { opacity: 1; pointer-events: auto; }

/* ---------- 抽屉菜单（手机端用） ---------- */
.side-nav-menu {
    position: fixed;
    top: 50%;
    right: 90px;
    transform: translateY(-50%) translateX(12px);
    z-index: 99;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease, transform 0.25s ease;
}
.side-nav-menu.open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(-50%) translateX(0);
}
.side-nav-menu-panel {
    background: var(--c-dark);
    border-radius: var(--radius-lg);
    padding: 8px;
    min-width: 200px;
    box-shadow: 0 12px 40px rgba(15, 42, 74, 0.35);
    display: flex;
    flex-direction: column;
    gap: 2px;
    position: relative;
}
.side-nav-menu-panel::after {
    content: "";
    position: absolute;
    right: -6px;
    top: 50%;
    transform: translateY(-50%);
    width: 0;
    height: 0;
    border: 6px solid transparent;
    border-left-color: var(--c-dark);
    border-right: 0;
}
.side-nav-menu-item {
    display: block;
    padding: 12px 16px;
    color: var(--c-text-faint);
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    border-radius: var(--radius-md);
    white-space: nowrap;
    transition: background 0.15s, color 0.15s;
    -webkit-tap-highlight-color: transparent;
}
.side-nav-menu-item:hover,
.side-nav-menu-item:active { background: rgba(56, 189, 248, 0.15); color: var(--c-primary-light); }
.side-nav-menu-item.active { background: var(--c-primary); color: #fff; }
.side-nav-menu-item-child {
    padding-left: 28px;
    font-size: 13px;
    color: var(--c-text-light);
}

/* 桌面端：菜单和遮罩层隐藏 */
@media (min-width: 901px) {
    .side-nav-menu,
    .side-nav-overlay {
        display: none !important;
    }
}

/* ============================================================
   手机端（≤900px）：只显示圆点
   ============================================================ */
@media (max-width: 900px) {
    .side-nav {
        right: 10px;
        padding: 10px 8px;
        border-radius: 999px;
    }
    .side-nav-item {
        padding: 4px;
        width: 28px;
        height: 28px;
        justify-content: center;
        border-radius: 50%;
        gap: 0;
    }
    /* 手机端隐藏文字和箭头 */
    .side-nav-item .side-nav-text,
    .side-nav-arrow {
        display: none;
    }
    .side-nav-dot {
        width: 12px;
        height: 12px;
    }
    .side-nav-item.active .side-nav-dot {
        box-shadow: 0 0 0 5px rgba(29, 111, 232, 0.18);
        transform: scale(1.15);
        animation: sideNavDotPulse 1.8s ease-in-out infinite;
    }
    @keyframes sideNavDotPulse {
        0%, 100% {
            box-shadow: 0 0 0 5px rgba(29, 111, 232, 0.18);
            transform: scale(1.15);
        }
        50% {
            box-shadow: 0 0 0 8px rgba(29, 111, 232, 0.10);
            transform: scale(1.30);
        }
    }
    .side-nav-item-child {
        padding-left: 4px;
    }
    /* 手机端菜单显示 */
    .side-nav-menu {
        right: 70px;
    }
    .side-nav-menu-panel {
        min-width: 180px;
        padding: 6px;
    }
    .side-nav-menu-item {
        padding: 11px 14px;
        font-size: 13px;
    }
}

/* 减少动画偏好（无障碍） */
@media (prefers-reduced-motion: reduce) {
    .side-nav-item.active .side-nav-arrow,
    .side-nav-item.active .side-nav-dot,
    .side-nav-item.pop .side-nav-text {
        animation: none;
    }
}

/* ============================================================
   手机端气泡
   ============================================================ */
.side-nav-bubble {
    position: fixed;
    z-index: 100;
    padding: 8px 14px;
    background: var(--c-dark);
    color: #fff;
    font-size: 13px;
    font-weight: 600;
    border-radius: var(--radius-sm);
    white-space: nowrap;
    pointer-events: none;
    opacity: 0;
    transform: translateY(-50%) scale(0.9);
    transition: opacity 0.25s ease, transform 0.25s ease;
    display: none;   /* 桌面端隐藏 */
    box-shadow: 0 4px 12px rgba(15, 42, 74, 0.25);
}

.side-nav-bubble.show {
    opacity: 1;
    transform: translateY(-50%) scale(1);
}

.side-nav-bubble::after {
    content: "";
    position: absolute;
    right: -6px;
    top: 50%;
    transform: translateY(-50%);
    border: 6px solid transparent;
    border-left-color: var(--c-dark);
    border-right: 0;
}

@media (max-width: 900px) {
    .side-nav-bubble {
        display: block;
    }
}


/* ============================================================
   手机端：激活圆点变成"展开图标"（三点）
   ============================================================ */
@media (max-width: 900px) {
    .side-nav-item.active .side-nav-dot {
        position: relative;
        width: 22px;
        height: 22px;
        background: var(--c-primary);
        box-shadow: 0 0 0 5px rgba(29, 111, 232, 0.18);
        transform: none;
        animation: none;
    }

    .side-nav-item.active .side-nav-dot::before {
        content: "";
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        width: 3px;
        height: 3px;
        background: #fff;
        border-radius: 50%;
        box-shadow:
            -5px 0 0 0 #fff,
             5px 0 0 0 #fff;
    }
}