:root{--bg:#f6f8fb;--card:#fff;--accent:#2b6bf6;--danger:#e74c3c}
*{box-sizing:border-box;font-family:Segoe UI,system-ui,Arial}
body{background:var(--bg);margin:0;padding:20px}
.container{max-width:900px;margin:0 auto}
h1{margin:0 0 16px}
.controls{display:flex;gap:8px;align-items:center;margin-bottom:12px}
.file-label input{display:inline-block;margin-left:8px}
.card{background:var(--card);padding:16px;border-radius:8px;box-shadow:0 1px 4px rgba(0,0,0,.06);margin-bottom:12px}
.hidden{display:none}
.meta{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px}
.question{font-size:18px;margin-bottom:12px}
.options{display:flex;flex-direction:column;gap:8px}
.options button{padding:10px 12px;border:1px solid #ddd;border-radius:6px;background:#fff;text-align:left}
.options button.correct{background:#e6ffed;border-color:#7bd389}
.options button.wrong{background:#ffecec;border-color:#f29b9b}
.feedback{min-height:24px;margin:12px 0}
.nav{display:flex;gap:8px}
#list{list-style:none;padding:0;margin:8px 0}
#list li{padding:8px;border-bottom:1px solid #eee}
.wrong-options{margin-top:6px;color:#555;font-size:13px}
.flag{background:transparent;border:none;font-size:18px}
.mark{background:#f0f0f0;border:1px solid #ccc;padding:6px;border-radius:6px}
footer{color:#666;margin-top:12px}