:root {
    --bg: #0b0f19; --surface: #111827; --card: rgba(31, 41, 55, 0.6);
    --text: #f9fafb; --text-muted: #9ca3af; --primary: #3b82f6; --accent: #06b6d4;
    --border: rgba(255,255,255,0.1); --radius: 12px; --font: system-ui, -apple-system, sans-serif;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { background: var(--bg); color: var(--text); font-family: var(--font); line-height: 1.6; }
a { color: inherit; text-decoration: none; transition: 0.2s; }
a:hover { color: var(--accent); }
.container { max-width: 1200px; margin: 0 auto; padding: 0 1.5rem; }
.header-inner, .footer-inner { display: flex; align-items: center; justify-content: space-between; padding: 1rem 0; }
.logo { font-size: 1.8rem; font-weight: 800; letter-spacing: -1px; }
.logo span { color: var(--primary); }
.nav-menu { display: flex; gap: 1.5rem; }
.lang-switch a { padding: 0.4rem 0.8rem; border: 1px solid var(--border); border-radius: 6px; font-size: 0.9rem; }
.menu-toggle { display: none; background: none; border: none; color: var(--text); font-size: 1.5rem; cursor: pointer; }

main { padding: 4rem 0 6rem; }
h1 { font-size: clamp(2rem, 5vw, 3.5rem); font-weight: 800; line-height: 1.1; margin-bottom: 1rem; background: linear-gradient(90deg, var(--text), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
h2 { font-size: 2rem; margin-bottom: 1.5rem; }
p { color: var(--text-muted); margin-bottom: 1.5rem; }
.section { margin-bottom: 4rem; }
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 2rem; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 2rem; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1.5rem; }

.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 2rem; backdrop-filter: blur(10px); transition: transform 0.2s, box-shadow 0.2s; }
.card:hover { transform: translateY(-4px); box-shadow: 0 10px 30px rgba(0,0,0,0.3); border-color: var(--primary); }
.card h3 { font-size: 1.3rem; margin-bottom: 0.5rem; color: var(--text); }
.card p { font-size: 0.95rem; margin-bottom: 0; }

.stat-box { text-align: center; padding: 2.5rem 1rem; background: var(--surface); border-radius: var(--radius); border: 1px solid var(--border); }
.stat-box .num { font-size: 2.8rem; font-weight: 800; color: var(--accent); display: block; margin-bottom: 0.5rem; }
.stat-box .label { color: var(--text-muted); font-size: 0.9rem; }

.timeline { position: relative; padding-left: 2rem; border-left: 2px solid var(--border); }
.timeline-item { margin-bottom: 2rem; position: relative; padding-left: 1.5rem; }
.timeline-item::before { content: ''; position: absolute; left: -2.35rem; top: 0.4rem; width: 12px; height: 12px; background: var(--primary); border-radius: 50%; border: 2px solid var(--bg); }
.timeline-year { font-weight: 700; color: var(--accent); font-size: 0.9rem; margin-bottom: 0.3rem; }

.partner-logo { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; height: 80px; display: flex; align-items: center; justify-content: center; font-weight: 600; color: var(--text-muted); }
.partner-logo:hover { border-color: var(--primary); color: var(--text); }

.btn { display: inline-block; padding: 0.8rem 2rem; background: var(--primary); color: white; border-radius: 8px; font-weight: 600; margin-top: 1rem; }
.btn:hover { background: #2563eb; }

.site-footer { border-top: 1px solid var(--border); padding: 2rem 0; margin-top: 4rem; }
.footer-inner { flex-wrap: wrap; gap: 1rem; }
.footer-links { display: flex; gap: 1.5rem; font-size: 0.9rem; }

@media (max-width: 768px) {
    .nav-menu { display: none; flex-direction: column; position: absolute; top: 60px; left: 0; right: 0; background: var(--surface); padding: 1.5rem; border-bottom: 1px solid var(--border); }
    .nav-menu.active { display: flex; }
    .menu-toggle { display: block; }
    h1 { font-size: 2.2rem; }
}

/* 确保 eleventy-img 生成的 picture 响应式正常 */
picture, picture img {
    width: 100%;
    height: auto;
    display: block;
    object-fit: cover;
}
.partner-logo picture img {
    max-width: 120px;
    margin: 0 auto;
}
/* 🌐 语言下拉菜单 */
.lang-dropdown {
    position: relative;
    display: inline-block;
}

.lang-trigger {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.45rem 0.9rem;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s ease;
}

.lang-trigger:hover,
.lang-dropdown.open .lang-trigger {
    border-color: var(--primary);
    background: rgba(59, 130, 246, 0.1);
}

.lang-arrow {
    width: 12px;
    height: 12px;
    transition: transform 0.25s ease;
}

.lang-dropdown.open .lang-arrow {
    transform: rotate(180deg);
}

.lang-menu {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    min-width: 130px;
    padding: 0.4rem 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px) scale(0.98);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 100;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(10px);
}

.lang-dropdown.open .lang-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.lang-item {
    display: block;
    padding: 0.6rem 1rem;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    transition: background 0.15s, color 0.15s;
    cursor: pointer;
}

.lang-item:hover:not(.active) {
    background: rgba(255, 255, 255, 0.06);
    color: var(--text);
}

.lang-item.active {
    color: var(--primary);
    font-weight: 600;
    cursor: default;
    position: relative;
}

.lang-item.active::after {
    content: "✓";
    position: absolute;
    right: 1rem;
    font-size: 0.8rem;
    opacity: 0.8;
}

/* 移动端适配 */
@media (max-width: 768px) {
    .lang-menu {
        right: auto;
        left: 0;
    }
}

/* 重置列表默认样式 */
.lang-menu {
    list-style: none;
    padding: 0.4rem 0;
    margin: 0;
    /* 保留之前的定位、背景、阴影、动效样式 */
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    min-width: 130px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px) scale(0.98);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 100;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(10px);
}

.lang-dropdown.open .lang-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.lang-menu li { margin: 0; }

/* 键盘焦点样式（无障碍核心） */
.lang-item:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: -2px;
    border-radius: 4px;
}