* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', sans-serif;
}

body {
    background: linear-gradient(135deg, #0f172a, #1e293b);
    padding: 30px;
    color: #fff;
}

.container {
    width: 1000px;
    margin: auto;
    background: #ffffff;
    color: #111;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 15px 35px rgba(0,0,0,0.35);
}

header {
    height: 130px;
    background: linear-gradient(rgba(0,0,0,0.4), rgba(0,0,0,0.4)), url('https://picsum.photos/1000/200?travel') center/cover;
    display: flex;
    justify-content: center;
    align-items: center;
    color: white;
    font-size: 36px;
    font-weight: bold;
}

nav {
    height: 55px;
    background: #263c6b;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 40px;
}

nav a {
    color: white;
    text-decoration: none;
}

main {
    display: flex;
    min-height: 480px;
}

.left { width: 20%; background: #e0f2fe; padding: 25px; }
.content { width: 45%; padding: 25px; text-align: center; }
.right { width: 35%; background: #f8fafc; padding: 25px; }

footer {
    height: 60px;
    background: #111827;
    color: white;
    display: flex;
    justify-content: center;
    align-items: center;
}