:root{
--primary:#2563eb;
--primary-dark:#1e40af;
--bg:#f3f4f6;
--card:#ffffff;
--text:#1f2937;
--muted:#6b7280;
--radius:12px;
--shadow:0 10px 20px rgba(0,0,0,0.08);
}

*{box-sizing:border-box;}

body{
margin:0;
font-family:'Inter',sans-serif;
background:var(--bg);
color:var(--text);
}

header{
background:#fff;
border-bottom:1px solid #e5e7eb;
padding:15px 0;
}

.nav{
max-width:1100px;
margin:auto;
padding:0 20px;
display:flex;
justify-content:space-between;
align-items:center;
}

.logo{
font-weight:700;
font-size:20px;
color:var(--primary);
text-decoration:none;
}

.container{
max-width:1100px;
margin:40px auto;
padding:0 20px;
display:grid;
grid-template-columns:1fr 320px;
gap:30px;
}

.card{
background:var(--card);
padding:30px;
border-radius:var(--radius);
box-shadow:var(--shadow);
}

input{
width:100%;
padding:12px;
margin-top:10px;
border:2px solid #e5e7eb;
border-radius:8px;
}

button{
width:100%;
padding:14px;
margin-top:20px;
background:var(--primary);
color:#fff;
border:none;
border-radius:8px;
font-weight:600;
cursor:pointer;
}

button:hover{background:var(--primary-dark);}

.result{
margin-top:20px;
background:#eff6ff;
padding:20px;
border-radius:8px;
display:none;
}

.sidebar .card{
box-shadow:0 2px 8px rgba(0,0,0,0.05);
}

.ad{
background:#e5e7eb;
height:250px;
display:flex;
align-items:center;
justify-content:center;
border-radius:8px;
color:#9ca3af;
}

footer{
background:#111827;
color:#9ca3af;
text-align:center;
padding:40px 0;
margin-top:60px;
}

@media(max-width:768px){
.container{grid-template-columns:1fr;}
}