/* ==========================================================
   灵溪 Lyncia — Global Stylesheet
   Taste: Web-Craft (Stripe-minimal × Tech Water)
   Palette: 蓝 → 青 → 绿，科技水感（2026 品牌重塑）
   ========================================================== */

:root {
    --canvas: #08122d;         /* Deep Navy */
    --ink: #ffffff;            /* Inverted White */
    --tech-blue: #4c7ff2;      /* 主色1（蓝） */
    --tech-teal: #66c1c9;      /* 主色2（青） */
    --tech-green: #69ac84;     /* 主色3（绿，点缀色） */
    --accent-2: var(--tech-teal); /* 承接旧 warm-red 的"第二强调色"语义 */
    --accent: var(--tech-blue);
    --grad: linear-gradient(135deg, var(--tech-blue), var(--tech-teal));
    --grad-logo: linear-gradient(90deg, var(--tech-blue), var(--tech-teal), var(--tech-green));
    --grad-soft: linear-gradient(135deg, rgba(76, 127, 242, 0.14), rgba(102, 193, 201, 0.1));
    --muted: #8ba0c0;          /* Slate Blue（深色主题次级文字） */
    --surface: #0b1b35;        /* Card Surface */
    --border: #1c3050;         /* Subtle Divider */
    --font-serif: var(--font-sans); /* 新品牌全线无衬线，保留变量名以兼容既有引用 */
    --font-sans: "Noto Sans SC", "Inter", system-ui, sans-serif;
    --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    background-color: var(--canvas);
    color: var(--ink);
    font-family: var(--font-sans);
    -webkit-font-smoothing: antialiased;
}

body {
    overflow-x: hidden;
    background-color: var(--canvas);
}

/* ── 水流渐变滚动条 ── */
::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: #081019; }
::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--tech-blue), var(--tech-teal), var(--tech-green));
    border-radius: 5px;
    border: 2px solid #081019;
}

/* Typography */
h1, h2, h3, h4 {
    font-family: var(--font-serif);
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

p {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--muted);
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition);
}

/* 蓝→青渐变文字（纯 CSS，截图安全） */
.grad-text {
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}

/* Layout */
.container {
    width: 100%;
    max-width: 80%;
    min-width: 0;
    margin: 0 auto;
    padding: 0 2rem;
}

/* 页眉 / 页脚不受 80% 宽度上限约束，保持通栏铺满 */
.navbar .container,
.footer .container {
    max-width: 100%;
}

section {
    position: relative;
    padding: 7rem 0;
}

/* 分割线：微弱的水流渐变（替代生硬的 border-bottom） */
section::after {
    content: "";
    position: absolute;
    bottom: 0; left: 0;
    width: 100%; height: 1px;
    background: linear-gradient(90deg,
        rgba(76, 127, 242, 0.4),
        rgba(102, 193, 201, 0.22) 55%,
        transparent 95%);
    pointer-events: none;
}
section.no-divider::after { display: none; }

/* ── 溪水线条：贯穿全站的动态波光分割线 ── */
.flow-line {
    height: 2px;
    width: 100%;
    background: linear-gradient(90deg,
        transparent, var(--tech-blue) 30%, var(--tech-teal) 65%, transparent);
    background-size: 200% 100%;
    opacity: 0.55;
    animation: flowShimmer 7s linear infinite;
}
@keyframes flowShimmer {
    0%   { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* SVG 波浪条（页面区块之间的溪水过渡） */
.water-divider {
    position: relative;
    height: 64px;
    overflow: hidden;
    pointer-events: none;
}
.water-divider svg {
    position: absolute;
    top: 0; left: 0;
    width: 200%; height: 100%;
    animation: waveDrift 22s linear infinite;
}
.water-divider svg.wave-back {
    animation-duration: 34s;
    animation-direction: reverse;
    opacity: 0.5;
}
@keyframes waveDrift {
    0%   { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

/* ── Navbar：吸顶导航，滚动后收缩为与页面核心内容等宽的半透明浮动胶囊 ── */
.navbar {
    position: fixed;
    top: 0; left: 0;
    width: 101%;
    z-index: 1000;
    padding: 0.5rem 0;
    transition: padding .45s cubic-bezier(.4,0,.2,1);
}

.navbar.scrolled {
    padding: 0.9rem 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1.5rem;
    border-radius: 999px;
    border: 1px solid transparent;
    background-color: rgba(8, 16, 30, 0.78);
    backdrop-filter: blur(12px) saturate(150%);
    box-shadow: 0 6px 24px rgba(2, 8, 20, 0.22);
    transition: max-width .5s cubic-bezier(.4,0,.2,1), background-color .4s ease,
        backdrop-filter .4s ease, border-color .4s ease, box-shadow .4s ease, padding .4s ease;
}

.navbar.scrolled .container {
    max-width: 80%;
    background-color: rgba(8, 16, 30, 0.94);
    backdrop-filter: blur(20px) saturate(170%);
    border-color: var(--border);
    box-shadow: 0 14px 38px rgba(2, 8, 20, 0.4);
    padding: 0.6rem 2rem;
}
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    white-space: nowrap;
}

.logo-img {
    height: 2.9rem;
    width: auto;
    display: block;
}

.footer-brand .logo-img { height: 3.1rem; }

.nav-links {
    display: flex;
    gap: 2.2rem;
    list-style: none;
}

.nav-links a {
    font-size: 1.05rem;
    font-weight: 500;
    color: var(--muted);
    white-space: nowrap;
}

.nav-links a:hover { color: var(--ink); }

.nav-links a.active {
    color: var(--ink);
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    font-weight: 700;
}

/* ── 导航「产品」下拉菜单：hover 展开，合并咨询师/医师 + AI 与 家庭 + AI ── */
.nav-item-dropdown { position: relative; }
/* 隐形桥接区：填补 toggle 与下拉面板之间的间隙，避免鼠标移动途中 hover 状态中断 */
.nav-item-dropdown::before {
    content: "";
    position: absolute;
    top: 100%; left: 0; right: 0;
    height: .9rem;
}
.nav-dropdown-toggle { display: inline-flex; align-items: center; gap: .35rem; cursor: default; }
/* 用纯几何边框三角形代替 Unicode 箭头字符：字符的字形墨迹在其字框内往往不对称/不居中，
   旋转 180° 时视觉上会显得偏移；边框三角形的包围盒本身即是形状主体，旋转后严格对称。
   同时不依赖 color/-webkit-text-fill-color，避免被 .active 的渐变文字（text-fill:transparent）连带隐藏。 */
.nav-dropdown-toggle::after {
    content: "";
    width: 0; height: 0;
    border-left: 4px solid transparent;
    border-right: 4px solid transparent;
    border-top: 5px solid var(--muted);
    opacity: .8;
    transition: transform .3s ease;
}
.nav-item-dropdown:hover .nav-dropdown-toggle::after,
.nav-item-dropdown:focus-within .nav-dropdown-toggle::after { transform: rotate(180deg); }
.nav-dropdown-menu {
    position: absolute;
    top: 100%; left: 50%;
    min-width: 300px;
    margin-top: .9rem;
    padding: .6rem;
    list-style: none;
    background-color: rgba(8, 16, 30, .94);
    backdrop-filter: blur(20px) saturate(170%);
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: 0 14px 38px rgba(2, 8, 20, .4);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateX(-50%) translateY(-6px);
    transition: opacity .25s ease, transform .25s ease, visibility .25s ease;
    z-index: 1200;
}
.nav-item-dropdown:hover .nav-dropdown-menu,
.nav-item-dropdown:focus-within .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}
.nav-dropdown-menu li + li { margin-top: .2rem; }
.nav-dropdown-menu a {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: .75rem 1rem;
    border-radius: 10px;
    font-size: .98rem;
    white-space: nowrap;
}
.nav-dropdown-menu a:hover { background-color: rgba(76, 127, 242, .12); }
.nav-dropdown-brand {
    font-size: .78rem;
    font-weight: 700;
    letter-spacing: .02em;
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    white-space: nowrap;
}
[data-theme="light"] .nav-dropdown-menu {
    background-color: rgba(241, 247, 253, .97);
    box-shadow: 0 14px 32px rgba(76, 127, 242, .16);
}
[data-theme="light"] .nav-dropdown-menu a:hover { background-color: rgba(76, 127, 242, .08); }

.nav-cta {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* ── 中/EN 语言切换 ── */
.lang-toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.45rem 0.9rem;
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 50px;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--muted);
    transition: var(--transition);
    letter-spacing: 0.03em;
}
.lang-toggle:hover { border-color: var(--tech-blue); }
.lang-toggle .lang-opt { transition: var(--transition); }
.lang-toggle .lang-opt.on {
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    font-weight: 700;
}
.lang-toggle .lang-sep { color: var(--border); }

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 500;
    border-radius: 50px;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--grad);
    color: #081018;
    font-weight: 700;
}
.btn-primary:hover {
    opacity: 0.92;
    transform: translateY(-1px);
    box-shadow: 0 6px 22px rgba(76, 127, 242, 0.25);
}

.btn-secondary {
    background-color: transparent;
    color: var(--ink);
    border: 1px solid var(--border);
}
.btn-secondary:hover {
    background-color: var(--surface);
    border-color: var(--muted);
}

.btn-disabled {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: 50px;
    background-color: transparent;
    color: var(--muted);
    border: 1px solid var(--border);
    cursor: not-allowed;
    user-select: none;
    pointer-events: none;
    opacity: 0.45;
}

/* ── Hero ── */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 6rem;
    overflow: hidden;
}

.hero-canvas {
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 1;
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 2;
}

.hero-content { text-align: left; }

.hero-tag {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    color: var(--tech-blue);
    margin-bottom: 1.5rem;
}

.hero-title {
    font-size: 3.5rem;
    color: var(--ink);
    margin-bottom: 1.5rem;
}

.hero-desc {
    font-size: 1.15rem;
    color: var(--muted);
    margin-bottom: 2.5rem;
    max-width: 600px;
    line-height: 1.75;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

/* 协同品牌背书 */
.hero-trust {
    border-top: 1px solid var(--border);
    padding-top: 2rem;
}
.hero-trust-title {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--muted);
    margin-bottom: 1rem;
    font-family: var(--font-sans);
    font-weight: 600;
}
.hero-trust-logos {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.25rem 0;
}
.hero-trust-logo {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--muted);
    white-space: nowrap;
}
.hero-trust-logo small {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.72rem;
    font-weight: 400;
    color: #536b7d;
    letter-spacing: 0.04em;
}
.hero-trust-sep {
    color: #2a4055;
    margin: 0 1.25rem;
    user-select: none;
}

/* ── Cards & Grid ── */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 2rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }

.card {
    background-color: var(--surface);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 2.5rem;
    transition: var(--transition);
    text-align: left;
    position: relative;
    overflow: hidden;
}
.card:hover {
    transform: translateY(-4px);
    border-color: var(--tech-blue);
}
/* 卡片顶部的蓝→青微渐变 */
.card.grad-top::before {
    content: "";
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 2px;
    background: var(--grad);
    opacity: 0.75;
}

/* 图标徽章：圆角方形 + 蓝→青渐变底，card-icon 原本就是包裹图标/编号的容器 */
.card-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 3rem;
    height: 3rem;
    font-size: 1.2rem;
    font-weight: 700;
    color: #ffffff;
    background: var(--grad);
    border-radius: 12px;
    margin-bottom: 1.5rem;
}
.card-title { font-size: 1.45rem; color: var(--ink); margin-bottom: 1rem; }
.card-desc { font-size: 0.95rem; color: var(--muted); line-height: 1.65; }
.card-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--tech-blue);
    margin-top: 1.25rem;
}
.card-link:hover { gap: 0.7rem; color: var(--tech-teal); }

/* ── Section Header ── */
.section-header {
    text-align: left;
    margin-bottom: 4rem;
    max-width: 800px;
}
.section-tag {
    font-family: var(--font-sans);
    font-size: 0.82rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--muted);
    margin-bottom: 1rem;
    display: inline-block;
}
.section-title { font-size: 2.4rem; color: var(--ink); margin-bottom: 1rem; }
.section-desc { font-size: 1.08rem; color: var(--muted); line-height: 1.7; }

/* ── Stats ── */
.stat-card {
    border-left: 3px solid;
    border-image: linear-gradient(180deg, var(--tech-blue), var(--tech-teal)) 1;
    padding-left: 1.5rem;
    text-align: left;
}
.stat-num {
    font-family: var(--font-serif);
    font-size: 2.6rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 0.4rem;
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}
.stat-label { font-size: 0.92rem; color: var(--ink); font-weight: 500; }
.stat-desc { font-size: 0.85rem; color: var(--muted); margin-top: 0.25rem; }

/* ── 免登录体验沙盒（B/C 通用） ── */
.sandbox-overlay {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    background: rgba(6, 13, 23, 0.82);
    backdrop-filter: blur(6px);
}
.sandbox-overlay[hidden] { display: none; }

.sandbox-modal {
    width: 100%;
    max-width: 640px;
    max-height: 88vh;
    display: flex;
    flex-direction: column;
    background: #0d1c2b;
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 30px 80px rgba(0, 0, 0, 0.6);
}
.sandbox-modal::before {
    content: "";
    display: block;
    height: 3px;
    background: var(--grad);
    flex-shrink: 0;
}

.sandbox-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1.1rem 1.5rem;
    border-bottom: 1px solid var(--border);
}
.sandbox-title {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    color: var(--ink);
}
.sandbox-sub {
    font-size: 0.78rem;
    color: var(--muted);
    margin-top: 0.15rem;
}
.sandbox-round {
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    color: var(--tech-blue);
    white-space: nowrap;
}
.sandbox-close {
    background: none;
    border: 1px solid var(--border);
    border-radius: 4px;
    color: var(--muted);
    width: 32px; height: 32px;
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    transition: var(--transition);
    flex-shrink: 0;
}
.sandbox-close:hover { color: var(--ink); border-color: var(--tech-teal); }

.sandbox-body {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    min-height: 280px;
}

/* 场景选择 */
.sandbox-scenarios { display: flex; flex-direction: column; gap: 1rem; }
.sandbox-scenario-btn {
    text-align: left;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 1.25rem 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
    color: var(--ink);
}
.sandbox-scenario-btn:hover { border-color: var(--tech-blue); transform: translateX(4px); }
.sandbox-scenario-btn .sc-name { font-weight: 700; font-size: 1rem; display: block; margin-bottom: 0.3rem; }
.sandbox-scenario-btn .sc-desc { font-size: 0.85rem; color: var(--muted); display: block; line-height: 1.5; }

/* 聊天气泡 */
.sb-msg {
    max-width: 88%;
    padding: 0.85rem 1.1rem;
    border-radius: 8px;
    font-size: 0.92rem;
    line-height: 1.6;
    color: var(--ink);
}
.sb-msg .sb-sender {
    display: block;
    font-size: 0.72rem;
    color: var(--muted);
    margin-bottom: 0.3rem;
    letter-spacing: 0.03em;
}
.sb-msg.ai {
    align-self: flex-start;
    background: rgba(76, 127, 242, 0.1);
    border: 1px solid rgba(76, 127, 242, 0.25);
    border-bottom-left-radius: 2px;
}
.sb-msg.role2 {
    align-self: flex-start;
    background: rgba(105, 172, 132, 0.1);
    border: 1px solid rgba(105, 172, 132, 0.28);
    border-bottom-left-radius: 2px;
}
.sb-msg.user {
    align-self: flex-end;
    background: var(--border);
    border-bottom-right-radius: 2px;
}
.sb-msg.narrator {
    align-self: center;
    max-width: 100%;
    background: transparent;
    border: 1px dashed var(--border);
    color: var(--muted);
    font-size: 0.82rem;
    text-align: center;
}
/* 多模态线索 chip */
.sb-meta {
    align-self: flex-start;
    font-size: 0.75rem;
    color: var(--tech-blue);
    background: rgba(76, 127, 242, 0.07);
    border: 1px dashed rgba(76, 127, 242, 0.35);
    border-radius: 4px;
    padding: 0.4rem 0.75rem;
    line-height: 1.5;
}
/* 督导 / 教练反馈 chip */
.sb-feedback {
    align-self: stretch;
    font-size: 0.8rem;
    line-height: 1.55;
    color: #b8e0c8;
    background: rgba(105, 172, 132, 0.08);
    border-left: 2px solid var(--tech-green);
    border-radius: 0 4px 4px 0;
    padding: 0.6rem 0.9rem;
}

/* 建议回复 */
.sandbox-suggestions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    padding: 0 1.5rem 0.75rem;
}
.sb-suggestion {
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 50px;
    color: var(--muted);
    font-family: var(--font-sans);
    font-size: 0.8rem;
    padding: 0.45rem 1rem;
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
}
.sb-suggestion:hover { border-color: var(--tech-blue); color: var(--ink); }

/* 输入栏 */
.sandbox-inputbar {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 1rem 1.5rem 1.25rem;
    border-top: 1px solid var(--border);
}
.sb-modal-icon {
    width: 36px; height: 36px;
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: 50%;
    color: var(--muted);
    background: none;
    cursor: pointer;
    transition: var(--transition);
}
.sb-modal-icon:hover { border-color: var(--tech-blue); color: var(--tech-blue); }
.sandbox-input {
    flex: 1;
    background: var(--canvas);
    border: 1px solid var(--border);
    border-radius: 50px;
    padding: 0.7rem 1.2rem;
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 0.9rem;
    transition: var(--transition);
    min-width: 0;
}
.sandbox-input:focus { outline: none; border-color: var(--tech-blue); }
.sandbox-send {
    background: var(--grad);
    color: #081018;
    border: none;
    border-radius: 50px;
    font-family: var(--font-sans);
    font-weight: 700;
    font-size: 0.88rem;
    padding: 0.7rem 1.4rem;
    cursor: pointer;
    transition: var(--transition);
    flex-shrink: 0;
}
.sandbox-send:hover { opacity: 0.9; }
.sandbox-send:disabled, .sandbox-input:disabled { opacity: 0.4; cursor: not-allowed; }

/* 评估结果面板 */
.sandbox-eval {
    border-top: 1px solid var(--border);
    padding: 1.5rem;
    background: rgba(17, 34, 51, 0.6);
}
.sandbox-eval-title {
    font-family: var(--font-serif);
    font-size: 1.05rem;
    color: var(--ink);
    margin-bottom: 1.1rem;
}
.sb-eval-row { margin-bottom: 0.9rem; }
.sb-eval-info {
    display: flex;
    justify-content: space-between;
    font-size: 0.82rem;
    color: var(--muted);
    margin-bottom: 0.35rem;
}
.sb-eval-info b { color: var(--ink); font-weight: 600; }
.sb-eval-bar {
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
}
.sb-eval-fill {
    height: 100%;
    background: var(--grad);
    border-radius: 3px;
}
.sandbox-eval-note {
    font-size: 0.82rem;
    color: var(--muted);
    line-height: 1.6;
    margin: 1rem 0 1.25rem;
    border-left: 2px solid var(--tech-blue);
    padding-left: 0.9rem;
}
.sandbox-eval-actions { display: flex; gap: 0.75rem; flex-wrap: wrap; }

/* ── Footer ── */
.footer {
    background-color: #050b1c;
    padding: 0 0 1rem;
    border-top: none;
}
.footer .flow-line { margin-bottom: 5rem; }

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr repeat(3, 1fr);
    gap: 4rem;
    margin-bottom: 4rem;
}
.footer-brand .logo { margin-bottom: 1.25rem; }
.footer-brand p { font-size: 0.9rem; max-width: 300px; line-height: 1.6; }

.footer-links-col h4 {
    font-family: var(--font-sans);
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--ink);
    margin-bottom: 1.5rem;
}
.footer-links-col ul { list-style: none; }
.footer-links-col ul li { margin-bottom: 0.75rem; }
.footer-links-col ul li a { font-size: 0.9rem; color: var(--muted); }
.footer-links-col ul li a:hover { color: var(--ink); }

/* 三方协同 Logo 条 */
.footer-cobrand {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem 0;
    padding: 1.75rem 0;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    margin-bottom: 1rem;
}
.footer-cobrand-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: #536b7d;
    margin-right: 2rem;
    font-weight: 600;
}
.cobrand-logo {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--muted);
    white-space: nowrap;
}
.cobrand-logo small {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.7rem;
    font-weight: 400;
    color: #536b7d;
}
.cobrand-sep { color: #2a4055; margin: 0 1.5rem; user-select: none; }

.footer-bottom {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.35rem 1.25rem;
    text-align: center;
}
.footer-bottom p { margin: 0; font-size: 0.82rem; line-height: 1.5; color: var(--muted); }
.footer-bottom .footer-icp { flex: 0 0 auto; white-space: nowrap; }
.footer-icp a { color: inherit; }
.footer-icp a:hover { text-decoration: underline; }

/* ── Mobile Menu Toggle ── */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    cursor: pointer;
    background: none;
    border: none;
    z-index: 1001;
}
.menu-toggle span {
    display: block;
    width: 25px; height: 2px;
    background-color: var(--ink);
    transition: var(--transition);
}

/* ── Animations ──
   Default: visible (no-JS / screenshot fallback).
   <html class="js-loaded"> (set by common.js) enables hide→reveal. */
.fade-in { opacity: 1; transform: none; }
.js-loaded .fade-in {
    opacity: 0;
    transform: translateY(22px);
    transition: opacity 0.65s ease-out, transform 0.65s ease-out;
}
.js-loaded .fade-in.visible { opacity: 1; transform: none; }
.js-loaded .fade-in:nth-child(2) { transition-delay: 0.08s; }
.js-loaded .fade-in:nth-child(3) { transition-delay: 0.16s; }

/* ── Responsive ── */
@media (max-width: 1024px) {
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 3rem; }
    .nav-links { gap: 1.5rem; }
}

@media (max-width: 768px) {
    section { padding: 5rem 0; }
    .menu-toggle { display: flex; }
    .nav-links {
        position: fixed;
        top: 0; right: -100%;
        width: 80%; height: 100vh;
        background-color: var(--canvas);
        border-left: 1px solid var(--border);
        flex-direction: column;
        padding: 8rem 3rem;
        transition: var(--transition);
        gap: 2rem;
    }
    .nav-links.active { right: 0; }
    .nav-cta .btn { display: none; }
    .nav-dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
        transform: none;
        background: none;
        backdrop-filter: none;
        border: none;
        box-shadow: none;
        padding: .5rem 0 0 1rem;
        margin-top: .5rem;
        min-width: 0;
    }
    .nav-dropdown-toggle::after { display: none; }
    .nav-item-dropdown::before { display: none; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; gap: 2.5rem; }
    .hero-title { font-size: 2.4rem; }
    .hero-actions { flex-direction: column; }
    .hero-actions .btn { width: 100%; justify-content: center; }
    .hero-trust-sep, .cobrand-sep { display: none; }
    .hero-trust-logos, .footer-cobrand { flex-direction: column; align-items: flex-start; gap: 0.75rem; }
    .sandbox-modal { max-height: 92vh; }
}

/* ================================================================
   日间 / 夜间主题切换
   切换按钮：.theme-toggle（太阳☀ / 月亮🌙）
   浅色主题通过 [data-theme="light"] 覆盖 CSS 变量
   ================================================================ */

/* ── 切换按钮 ── */
.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.1rem;
    height: 2.1rem;
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 50%;
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    transition: var(--transition);
    color: var(--muted);
    flex-shrink: 0;
}
.theme-toggle:hover {
    border-color: var(--tech-blue);
    color: var(--ink);
    transform: rotate(20deg);
}

/* ── 浅色主题变量覆盖 ── */
[data-theme="light"] {
    --canvas: #f1f7fd;
    --ink: #111111;
    --tech-blue: #4c7ff2;
    --tech-teal: #66c1c9;
    --tech-green: #69ac84;
    --accent-2: var(--tech-teal);
    --accent: var(--tech-blue);
    --grad: linear-gradient(135deg, var(--tech-blue), var(--tech-teal));
    --grad-logo: linear-gradient(90deg, var(--tech-blue), var(--tech-teal), var(--tech-green));
    --grad-soft: linear-gradient(135deg, rgba(76,127,242,0.1), rgba(102,193,201,0.08));
    --muted: #666666;
    --surface: #ffffff;
    --border: #d8e3f0;
}

/* ── 浅色主题：html / body 背景 ── */
[data-theme="light"] html,
html[data-theme="light"] {
    background-color: #f1f7fd;
    color: #111111;
}
[data-theme="light"] body {
    background-color: #f1f7fd;
}

/* ── 浅色主题：滚动条 ── */
[data-theme="light"] ::-webkit-scrollbar-track { background: #dceaf6; }
[data-theme="light"] ::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, #4c7ff2, #66c1c9, #69ac84);
    border-color: #dceaf6;
}

/* ── 浅色主题：导航栏 ── */
[data-theme="light"] .navbar .container {
    background-color: rgba(241, 247, 253, 0.9);
    box-shadow: 0 6px 22px rgba(76, 127, 242, 0.1);
}
[data-theme="light"] .navbar.scrolled .container {
    background-color: rgba(241, 247, 253, 0.97);
    box-shadow: 0 14px 32px rgba(76, 127, 242, 0.16);
}
[data-theme="light"] .menu-toggle span { background-color: var(--ink); }
[data-theme="light"] .nav-links {
    background-color: var(--canvas);
    border-left-color: var(--border);
}

/* ── 浅色主题：卡片 ── */
[data-theme="light"] .card {
    background-color: #ffffff;
    border-color: var(--border);
    box-shadow: 0 2px 12px rgba(17,17,17,0.05);
}
[data-theme="light"] .card:hover {
    border-color: var(--tech-blue);
    box-shadow: 0 6px 24px rgba(76,127,242,0.12);
}
[data-theme="light"] .hero-stat-card {
    background-color: rgba(255,255,255,0.85);
    border-color: var(--border);
}
[data-theme="light"] .hero-stat-card::before {
    background: linear-gradient(180deg, #4c7ff2, #66c1c9);
}

/* ── 浅色主题：Hero ── */
[data-theme="light"] .hero {
    background-color: var(--canvas);
}

/* ── 浅色主题：section 分割线 ── */
[data-theme="light"] section::after {
    background: linear-gradient(90deg,
        rgba(76,127,242,0.3),
        rgba(102,193,201,0.18) 55%,
        transparent 95%);
}

/* ── 浅色主题：footer ── */
[data-theme="light"] .footer {
    background-color: #dceaf6;
}
[data-theme="light"] .footer-cobrand {
    border-color: var(--border);
}

/* ── 浅色主题：按钮 ── */
[data-theme="light"] .btn-secondary {
    background-color: rgba(255,255,255,0.6);
    border-color: var(--border);
    color: var(--ink);
}
[data-theme="light"] .btn-secondary:hover {
    background-color: #ffffff;
    border-color: var(--tech-blue);
}
[data-theme="light"] .btn-primary {
    color: #ffffff;
}

/* ── 浅色主题：lang-toggle ── */
[data-theme="light"] .lang-toggle {
    border-color: var(--border);
    color: var(--muted);
}

/* ── 浅色主题：沙盒弹窗 ── */
[data-theme="light"] .sandbox-overlay {
    background: rgba(17,17,17,0.55);
}
[data-theme="light"] .sandbox-modal {
    background: #f0f8ff;
    border-color: var(--border);
}
[data-theme="light"] .sandbox-head {
    background: linear-gradient(135deg, rgba(76,127,242,0.1), rgba(102,193,201,0.07));
    border-bottom-color: var(--border);
}
[data-theme="light"] .sb-msg.ai {
    background: #ffffff;
    border-color: var(--border);
}
[data-theme="light"] .sb-msg.user {
    background: linear-gradient(135deg, rgba(76,127,242,0.12), rgba(102,193,201,0.08));
}
[data-theme="light"] .sandbox-input {
    background: #ffffff;
    border-color: var(--border);
    color: var(--ink);
}
[data-theme="light"] .sandbox-inputbar {
    background: #f0f8ff;
    border-top-color: var(--border);
}

/* ── 浅色主题：B端页面专属 ── */
[data-theme="light"] .workspace-card {
    background-color: #ffffff;
    border-color: var(--border);
}
[data-theme="light"] .workspace-card:hover {
    border-color: var(--tech-blue);
}
[data-theme="light"] .feature-item {
    background-color: rgba(255,255,255,0.7);
    border-color: var(--border);
}

/* ── 浅色主题：C端页面专属 ── */
[data-theme="light"] .level-card {
    background-color: #ffffff;
    border-color: var(--border);
}
[data-theme="light"] .counselor-card {
    background-color: #ffffff;
    border-color: var(--border);
}
[data-theme="light"] .mode-card {
    background-color: #ffffff;
    border-color: var(--border);
}

/* ── 浅色主题：research 页面专属 ── */
[data-theme="light"] .research-hero {
    background-color: var(--canvas);
}
[data-theme="light"] .paper-card {
    background-color: #ffffff;
    border-color: var(--border);
}
[data-theme="light"] .collab-card {
    background-color: #ffffff;
    border-color: var(--border);
}

/* ── 浅色主题：about 页面专属 ── */
[data-theme="light"] .about-hero {
    background-color: var(--canvas);
}
[data-theme="light"] .team-card {
    background-color: #ffffff;
    border-color: var(--border);
}
[data-theme="light"] .value-card {
    background-color: #ffffff;
    border-color: var(--border);
}

/* ── 浅色主题：Canvas 粒子透明度调整（浅底上稍加深） ── */
[data-theme="light"] .hero-canvas {
    opacity: 0.45;
}

/* ── 主题切换过渡动画 ── */
html {
    transition: background-color 0.35s ease, color 0.35s ease;
}
body, .navbar, .card, .hero-stat-card, .footer,
.workspace-card, .level-card, .counselor-card, .mode-card,
.paper-card, .collab-card, .team-card, .value-card {
    transition: background-color 0.35s ease, border-color 0.35s ease,
                box-shadow 0.35s ease, color 0.35s ease;
}