body{font-family:sans-serif;margin:0;background:#f5f5f5;color:#111;}
header{display:flex;flex-wrap:wrap;gap:.5em;align-items:center;
       background:#006400;color:#fff;padding:.5em;}
header h1{flex:1;font-size:1.25em;margin:0}
button{padding:.4em .8em;font-size:1em;border:0;border-radius:4px}
button:disabled{opacity:.4}
main{padding:1em;max-width:800px;margin:auto}
.opt{margin:.4em 0;padding:.6em;border:1px solid #ccc;
     border-radius:4px;background:#fff;cursor:pointer}
.opt.correct{border-color:green;background:#cfc}
.opt.wrong{border-color:red;background:#fcc}
.rationale{font-style:italic;margin-top:.5em;}
#exam-chooser{display:flex;gap:.4em;border:0;margin:0;padding:0;color:#fff}
#exam-chooser label{display:flex;align-items:center;font-weight:bold}
#num-wrapper{display:flex;align-items:center;gap:.25em;font-weight:bold}

/* NEW – “I don’t know / Show answer” button */
.skip-btn{
  margin-top:.8em;padding:.5em 1em;font-size:1em;
  border:0;border-radius:4px;background:#eee;color:#111;cursor:pointer
}