:root {
    --black: #000;
    --white: #fff;
    --blue-light: #8ecae6;
    --blue-medium: #219ebc;
    --blue-dark: #023047;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: sans-serif;
    background-color: var(--black);
    color: var(--white);
    line-height: 1.6;
}

/* Header & Navbar */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--black);
    padding: 1rem 2rem;
    box-shadow: 0 2px 4px rgba(255, 255, 255, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--blue-medium);
}

.navbar ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
}

.navbar a {
    color: var(--white);
    text-decoration: none;
    transition: color 0.3s;
}

.navbar a:hover {
    color: var(--blue-light);
}

.burger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.burger span {
    width: 25px;
    height: 3px;
    background: var(--white);
    transition: 0.3s;
}

/* Sidebar */
.sidebar {
    background: var(--blue-dark);
    padding: 1rem;
    width: 200px;
    position: fixed;
    top: 70px;
    left: 0;
    height: calc(100% - 70px);
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.5);
    display: none;
}

.sidebar ul {
    list-style: none;
}

.sidebar a {
    color: var(--white);
    text-decoration: none;
    display: block;
    padding: 0.5rem 0;
}

.sidebar a:hover {
    color: var(--blue-light);
}

/* Main & Banner */
main {
    margin-left: 0;
    padding: 2rem;
    transition: margin-left 0.3s;
}

.banner {
    background: var(--blue-medium);
    color: var(--black);
    padding: 2rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    text-shadow: 1px 1px var(--white);
}

.content article {
    background: var(--blue-dark);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.05);
}

/* Footer */
footer {
    text-align: center;
    padding: 1rem;
    background: var(--black);
    color: var(--white);
    border-top: 1px solid var(--blue-dark);
}

/* Responsive */
@media (max-width: 768px) {
    .navbar ul {
        flex-direction: column;
        position: absolute;
        top: 70px;
        right: 0;
        background: var(--black);
        width: 100%;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease-in-out;
    }

    .nav-links.nav-active {
        max-height: 300px;
    }

    .burger {
        display: flex;
    }

    .sidebar {
        display: none;
    }

    main {
        margin-left: 0;
    }
}