:root{--bg:#f3f4f6;--card:#fff;--text:#111827;--muted:#6b7280;--line:#d1d5db;--accent:#111827}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;background:var(--bg);color:var(--text)}
header{padding:18px 16px;background:var(--accent);color:white}
h1{margin:0;font-size:24px}.sub{opacity:.85;margin-top:4px} h2{margin-top:0}
.tabs{max-width:900px;margin:0 auto;padding:12px 14px;display:flex;gap:8px}
main{max-width:900px;margin:0 auto;padding:0 14px 14px}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px;margin-bottom:12px;box-shadow:0 1px 2px rgba(0,0,0,.04)}
label{font-weight:700;display:block;margin-bottom:6px}
input,select,button{font:inherit}
input,select{width:100%;padding:12px;border:1px solid var(--line);border-radius:10px;background:white}
button{border:0;border-radius:10px;padding:12px 14px;background:var(--accent);color:white;font-weight:700}
button.secondary{background:#e5e7eb;color:#111827}
.mt{margin-top:12px}.hint{font-size:13px;color:var(--muted);margin-top:6px}
.grid2{display:grid;grid-template-columns:1fr;gap:8px}
@media(min-width:700px){.grid2{grid-template-columns:1fr 1fr}}
.hidden{display:none!important}
.qrBox{display:flex;justify-content:center;align-items:center;min-height:230px;border:1px dashed var(--line);border-radius:12px;background:#fafafa}
.qrBox img{width:220px;height:220px}
.linkBox{font-family:ui-monospace,Menlo,monospace;word-break:break-all;background:#f9fafb;border:1px solid var(--line);border-radius:10px;padding:10px}
.status{display:flex;justify-content:space-between;align-items:center}
#timer{font-size:28px;font-weight:800}
.task{border-bottom:1px solid var(--line);padding:12px 0}
.task:last-child{border-bottom:0}
.task-title{font-weight:800;margin-bottom:4px}.task-text{margin:4px 0 10px}
.solution{margin-top:8px;color:var(--muted);font-size:14px}
.good{border-color:#86efac;background:#f0fdf4}.bad{border-color:#fca5a5;background:#fef2f2}
footer{text-align:center;color:var(--muted);font-size:13px;padding:18px}