html,
body {
    padding: 0;
    height: 100%;
}

body {
    margin: 0;
    font-family: 'Open Sans', sans-serif;
    /* Background image with dark overlay */
    background-image: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)), url('correlation30.jpg');
    background-size: cover;
    /* scale and crop to fill screen */
    background-position: center;
    /* center the image */
    background-repeat: no-repeat;
    /* don't tile */
    background-attachment: fixed;
    /* optional: keep fixed on scroll */
    color: #f5f5f5;
    /* light text for contrast */
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    min-height: -webkit-fill-available;
}

nav {
    /* background-color: #000; */
    padding: 15px 0;
    text-align: center;
}

nav a {
    color: #f5f5f5;
    text-decoration: none;
    margin: 0 20px;
    font-weight: 600;
}

nav a:hover {
    color: #5374E8;
}

.container {
    max-width: 700px;
    margin: 80px auto;
    padding: 40px 30px;
    /* background-color: rgba(0, 0, 0, 0.5); */
    border-radius: 12px;
    text-align: center;
    animation: fadeIn 1.5s ease forwards;
    flex: 1 0 auto;
}

.container h1 {
    font-weight: 700;
    font-size: 3rem;
    margin-bottom: 20px;
    color: #f0f0f0;
}

.container p {
    font-size: 1.2rem;
    line-height: 1.6;
    color: #ddd;
    margin-bottom: 30px;
}

.container a img {
    width: 48px;
    height: 48px;
    margin: 0 12px;
    vertical-align: middle;
    filter: drop-shadow(0 0 2px rgba(0, 0, 0, 0.7));
    transition: filter 0.3s ease;
}

.container a img:hover {
    filter: drop-shadow(0 0 6px rgba(83, 116, 232, 0.9));
    cursor: pointer;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

h1,
h2 {
    font-weight: 600;
}

a {
    color: #5374E8;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

footer {
    flex-shrink: 0;
    text-align: center;
    padding: 40px 0;
    font-size: 0.9em;
    color: #888;
}

header {
    text-align: center;
    padding-top: 40px;
    margin-bottom: 0;
}