* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f5f7fa;
    color: #243044;
}
header {
    background: #17263c;
    color: white;
    display: flex;
    align-items: center;
    gap: 24px;
    padding: 32px max(24px, calc((100% - 900px)/2));
}
header h1 { margin: 0; }
header p { margin: 8px 0 0; }
.logo {
    font-size: 55px;
    color: #f7931a;
}
main {
    max-width: 900px;
    margin: 50px auto;
    padding: 35px;
    background: white;
    border-radius: 12px;
    min-height: 300px;
}
h2 { color: #17263c; }
p { line-height: 1.7; }
.bitcoin-image {
    width: 160px;
    display: block;
    margin: 30px auto;
}
.button {
    display: inline-block;
    background: #f7931a;
    color: white;
    padding: 12px 20px;
    text-decoration: none;
    border-radius: 6px;
}
footer {
    text-align: center;
    padding: 25px;
}
nav {
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}
nav a { color: #17263c; font-weight: bold; }

/* Bonus: stock quotes and visitor counter */
.stock-section {
    max-width: 900px;
    margin: 30px auto;
    padding: 15px;
}
.stock-section h3 {
    margin: 15px 0;
}
.stock-prices {
    line-height: 2;
    font-weight: 600;
}
.stock-section hr {
    border: 0;
    border-top: 1px solid #9ca3af;
}