/* KiddoMind 全站共用：导航 + 基础令牌 */
:root {
    --km-bg: #050510;
    --km-card: rgba(12, 18, 40, 0.88);
    --km-line: rgba(100, 200, 255, 0.22);
    --km-text: #ffffff;
    --km-muted: rgba(255, 255, 255, 0.65);
    --km-accent: #64c8ff;
    --km-accent-2: #a78bfa;
    --km-ok: #86efac;
    --km-radius: 18px;
    --km-nav-h: 56px;
    --km-safe-top: env(safe-area-inset-top, 0px);
    --km-safe-bottom: env(safe-area-inset-bottom, 0px);
}

.km-site-nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    min-height: var(--km-nav-h);
    padding: calc(8px + var(--km-safe-top)) 16px 8px;
    background: rgba(6, 10, 24, 0.82);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    backdrop-filter: blur(12px);
}

.km-site-nav a {
    color: inherit;
    text-decoration: none;
}

.km-brand {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 800;
    font-size: 16px;
    letter-spacing: 0.3px;
    white-space: nowrap;
}

.km-brand span.logo-mark {
    filter: drop-shadow(0 0 10px rgba(100, 200, 255, 0.55));
}

.km-nav-links {
    display: flex;
    align-items: center;
    gap: 4px;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.km-nav-links a {
    padding: 8px 12px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
    color: rgba(255, 255, 255, 0.78);
    transition: background 0.2s ease, color 0.2s ease;
}

.km-nav-links a:hover {
    background: rgba(255, 255, 255, 0.08);
    color: #fff;
}

.km-nav-links a.is-active {
    background: rgba(100, 200, 255, 0.2);
    color: #fff;
    box-shadow: 0 0 0 1px rgba(100, 200, 255, 0.35);
}

.km-nav-cta {
    padding: 8px 14px !important;
    border-radius: 999px !important;
    background: linear-gradient(135deg, #64c8ff, #4a9eff) !important;
    color: #fff !important;
    box-shadow: 0 6px 18px rgba(100, 200, 255, 0.28);
}

.km-nav-cta.is-active {
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.35), 0 6px 18px rgba(100, 200, 255, 0.28) !important;
}

/* 探索页：导航浮在场景上 */
body.page-planets .km-site-nav,
body.page-ocean .km-site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    background: rgba(6, 10, 24, 0.55);
}

body.page-ocean .km-site-nav {
    background: rgba(2, 20, 32, 0.55);
}

body.page-planets #header {
    top: calc(var(--km-nav-h) + 10px + var(--km-safe-top));
}

body.page-planets #age-selector {
    top: calc(var(--km-nav-h) + 10px + var(--km-safe-top));
}

body.page-planets #mode-badge {
    top: calc(var(--km-nav-h) + 12px + var(--km-safe-top));
}

body.page-planets #info-panel {
    top: calc(var(--km-nav-h) + 72px);
}

body.page-planets.layout-portrait #info-panel {
    top: auto;
}

@media (max-width: 720px) {
    .km-site-nav {
        padding-left: 10px;
        padding-right: 10px;
    }
    .km-brand .brand-text {
        display: none;
    }
    .km-nav-links a {
        padding: 7px 9px;
        font-size: 12px;
    }
    .km-nav-links a[data-nav="parents"] {
        display: none;
    }
}

@media (max-width: 900px) {
    body.page-planets #mode-badge {
        top: calc(var(--km-nav-h) + 48px + var(--km-safe-top));
    }
}