* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
    background: #f5f5f7;
    color: #1d1d1f;
}

header {
    background: white;
    border-bottom: 1px solid #e5e5e5;
    padding: 18px 24px;
    position: sticky;
    top: 0;
}

nav {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    gap: 18px;
    align-items: center;
    justify-content: space-between;
}

.brand {
    font-weight: 800;
    font-size: 20px;
}

.links {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

a {
    color: #007aff;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

main {
    max-width: 1000px;
    margin: 40px auto;
    padding: 0 20px;
}

.card {
    background: white;
    border-radius: 20px;
    padding: 36px;
    box-shadow: 0 10px 30px rgba(0,0,0,.08);
    margin-bottom: 24px;
}

.hero h1 {
    font-size: 44px;
    margin: 0 0 12px;
}

.hero p {
    font-size: 20px;
    line-height: 1.6;
}

h1, h2, h3 {
    margin-top: 0;
}

p, li {
    line-height: 1.7;
    font-size: 17px;
}

.button {
    display: inline-block;
    background: #007aff;
    color: white;
    padding: 12px 18px;
    border-radius: 12px;
    margin-top: 10px;
}

.button:hover {
    text-decoration: none;
}

.app-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 18px;
}

.app-card {
    background: #f5f5f7;
    border-radius: 16px;
    padding: 22px;
}

footer {
    max-width: 1000px;
    margin: 40px auto;
    padding: 20px;
    color: #666;
    text-align: center;
}

@media (max-width: 650px) {
    nav {
        align-items: flex-start;
        flex-direction: column;
    }

    .hero h1 {
        font-size: 34px;
    }

    .card {
        padding: 24px;
    }
}