:root {

    --bg: #ffffff;
    --text: #222;
    --card: #f5f5f5;
    --primary: #2563eb;

}


.dark {

    --bg: #111827;
    --text: #eeeeee;
    --card: #1f2937;

}



* {

    box-sizing:border-box;

}


body {

    margin:0;
    font-family:
        Arial,
        Helvetica,
        sans-serif;

    background:var(--bg);
    color:var(--text);

    line-height:1.6;

}



header {

    padding:20px;

}



nav {

    display:flex;
    justify-content:space-between;
    align-items:center;

}



.logo {

    font-size:28px;
    font-weight:bold;

}



button {

    border:none;
    padding:10px;
    cursor:pointer;

}



.hero {

    padding:100px 20px;
    text-align:center;

}


.hero h1 {

    font-size:48px;

}



.hero p {

    font-size:20px;

}



.button {

    display:inline-block;

    background:var(--primary);

    color:white;

    padding:14px 28px;

    border-radius:8px;

    text-decoration:none;

    margin-top:20px;

}



section {

    padding:50px 20px;

    max-width:1000px;

    margin:auto;

}



h2 {

    text-align:center;

    font-size:32px;

}



.cards {

    display:flex;

    gap:20px;

    flex-wrap:wrap;

}



.card {

    flex:1;

    min-width:250px;

    background:var(--card);

    padding:25px;

    border-radius:12px;

}



.placeholder {

    height:300px;

    background:var(--card);

    display:flex;

    align-items:center;

    justify-content:center;

    border-radius:12px;

}



footer {

    text-align:center;

    padding:30px;

}