HTTP 400: Missing Parameters.
    <style>
        .math-tex, .MathJax, .MathJax_Display { max-width: 100% !important; overflow-x: auto !important; overflow-y: hidden !important; -webkit-overflow-scrolling: touch !important; word-wrap: break-word !important; white-space: normal !important; }
        .math-tex::-webkit-scrollbar, .MathJax::-webkit-scrollbar { height: 4px; }
        .math-tex::-webkit-scrollbar-thumb, .MathJax::-webkit-scrollbar-thumb { background: rgba(0,0,0,0.15); border-radius: 4px; }
        body { -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; -webkit-touch-callout: none; }
        input, textarea, [contenteditable="true"] { -webkit-user-select: auto !important; user-select: auto !important; }
        img { -webkit-user-drag: none; user-drag: none; pointer-events: none; }
    </style>
    <script>
        document.addEventListener("DOMContentLoaded", function() {
            document.addEventListener("contextmenu", e => e.preventDefault());
            document.addEventListener("keydown", function(e) {
                if (e.key === "F12" || e.keyCode === 123) { e.preventDefault(); return false; }
                if ((e.ctrlKey || e.metaKey) && e.shiftKey && (e.key === "I" || e.key === "i" || e.key === "J" || e.key === "j" || e.key === "C" || e.key === "c")) { e.preventDefault(); return false; }
                if ((e.ctrlKey || e.metaKey) && (e.key === "S" || e.key === "s" || e.key === "P" || e.key === "p" || e.key === "U" || e.key === "u")) { e.preventDefault(); alert("⚠️ 系统资产受版权保护。"); return false; }
            });
        });
    </script>