.language-toggle {
    position: relative;
    display: inline-grid;
    grid-template-columns: 1fr 1fr;
    width: 216px;
    padding: 4px;
    border: 1px solid #d0dde5;
    border-radius: 100px;
    background: #eef3f7;
    touch-action: pan-y;
    user-select: none;
}

.language-thumb {
    position: absolute;
    top: 4px;
    bottom: 4px;
    left: 4px;
    width: calc(50% - 4px);
    border-radius: 100px;
    background: #2a4a5e;
    transition: transform 180ms ease;
    pointer-events: none;
}

.language-toggle[data-language="zh"] .language-thumb { transform: translateX(100%); }
.language-toggle a {
    position: relative;
    padding: 7px 12px;
    color: #2a4a5e;
    font-family: 'Source Sans 3', 'Noto Sans SC', sans-serif;
    font-size: 15px;
    font-weight: 600;
    line-height: 1.6;
    text-align: center;
    text-decoration: none;
    border-radius: 100px;
    transition: color 180ms ease;
}
.language-toggle[data-language="en"] a[data-language="en"],
.language-toggle[data-language="zh"] a[data-language="zh"] { color: #fff; }
.language-toggle a:focus-visible { outline: 2px solid #9ab5c8; outline-offset: 3px; }

@media (prefers-reduced-motion: reduce) {
    .language-thumb, .language-toggle a { transition: none; }
}