*{
margin:0;
padding:0;
box-sizing:border-box;
font-family:Arial,sans-serif;
}
.header{
width:100%;
background:#ffffff;
padding:15px 30px;
display:flex;
justify-content:space-between;
align-items:center;
box-shadow:0 2px 10px rgba(0,0,0,.1);
position:sticky;
top:0;
z-index:1000;
}

.logo a{
font-size:18px;
font-weight:bold;
color:#2196f3;
text-decoration:none;
}

nav{
display:flex;
gap:20px;
}

nav a{
font-size:14px;
text-decoration:none;
color:#333;
font-weight:bold;
transition:.3s;
}

nav a:hover{
color:#2196f3;
}

@media(max-width:600px){

.header{
flex-direction:column;
gap:10px;
padding:15px;
}

nav{
flex-wrap:wrap;
justify-content:center;
}

}
main{
flex:1;
display:flex;
justify-content:center;
align-items:center;
padding:20px;
}
.container{
background:#fff;
max-width:420px;
width:100%;
padding:30px;
border-radius:15px;
box-shadow:0 10px 30px rgba(0,0,0,.2);
text-align:center;
}

h1{
color:#222;
margin-bottom:10px;
}

p{
color:#666;
margin-bottom:20px;
}

input{
width:100%;
padding:15px;
font-size:18px;
border:2px solid #ddd;
border-radius:8px;
outline:none;
margin-bottom:20px;
}

input:focus{
border-color:#2196f3;
}

button{
width:100%;
padding:15px;
font-size:18px;
background:#2196f3;
color:#fff;
border:none;
border-radius:8px;
cursor:pointer;
}

button:hover{
background:#1565c0;
}

.result{
display:none;
margin-top:25px;
background:#f5f5f5;
padding:20px;
border-radius:10px;
}

.box{
display:flex;
justify-content:space-between;
padding:12px;
background:#fff;
margin:10px 0;
border-radius:8px;
font-size:18px;
}

.seo-content{
max-width:900px;
margin:40px auto;
padding:30px;
background:#fff;
border-radius:15px;
box-shadow:0 5px 20px rgba(0,0,0,.08);
line-height:1.8;
}

.seo-content h2{
color:#222;
margin:25px 0 15px;
font-size:28px;
}

.seo-content h3{
margin-top:20px;
color:#444;
font-size:22px;
}

.seo-content p,
.seo-content li{
font-size:17px;
color:#555;
}

.seo-content ul,
.seo-content ol{
padding-left:25px;
}