body{
margin:0;
font-family:sans-serif;
background:#f4f7fb;
}

header{
background:#111827;
color:white;
padding:20px;
text-align:center;
}

nav{
display:flex;
gap:10px;
justify-content:center;
flex-wrap:wrap;
padding:15px;
background:white;
}

nav a{
padding:10px 15px;
border-radius:999px;
background:#e5e7eb;
text-decoration:none;
color:black;
font-weight:bold;
}

.active{
background:#2563eb;
color:white;
}

.layout{
max-width:1200px;
margin:auto;
padding:20px;
display:grid;
grid-template-columns:1fr 320px;
gap:20px;
}

.quiz-box{
background:white;
padding:25px;
border-radius:20px;
box-shadow:0 4px 15px rgba(0,0,0,0.1);
}

.status{
display:flex;
justify-content:space-between;
margin-bottom:15px;
font-weight:bold;
}

.progress{
height:10px;
background:#ddd;
border-radius:999px;
overflow:hidden;
margin-bottom:20px;
}

#bar{
height:100%;
width:0%;
background:#22c55e;
}

#choices{
display:grid;
gap:12px;
}

#choices button{
padding:16px;
font-size:18px;
border:none;
border-radius:12px;
background:#f1f5f9;
cursor:pointer;
font-weight:bold;
}

.correct{
background:#86efac !important;
}

.wrong{
background:#fca5a5 !important;
}

.ad-side{
background:white;
padding:15px;
border-radius:20px;
height:fit-content;
position:sticky;
top:20px;
}

@media(max-width:900px){

.layout{
grid-template-columns:1fr;
}

  #choices {
  display: grid;
  gap: 12px;
  margin-top: 24px;
}

.choice-btn {
  display: block;
  width: 100%;
  padding: 14px 16px;
  border: none;
  border-radius: 10px;
  background: #eef2ff;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
  text-align: left;
}

.choice-btn:hover {
  background: #dbe4ff;
}

}