:root { 
    --primary: #99bfc9;
    --secondary: #fff;
    --nava: blue;
    --footer-background-color: #000;
}

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

html, body {
    width: 100%;
    height: 100dvh;
    font-family: 'Times New Roman', Times, serif;
    scroll-behavior: smooth;
}

/* Header */
header {
    padding: 35px 0;
    background-color: #333;
}

nav {
    background: #333;
    overflow: hidden;
}

nav.sticky {
    position: fixed;
    top: 0;
    width: 100%;
}

nav li {
    display: block;
    float: right;
    padding-right: 45px;
}

/* logo */
nav > li {
    padding-left: 45px;
    font-weight: 700;
    float: left;
}

nav a {
    position: relative;
    display: block;
    padding: 10px;
    text-decoration: none;
    color: var(--primary);
    font-size: 1.2em;
}

nav .active {
    color: #eee;
}

@keyframes a {
    from { width: 0; }
    to { width: 65px; }
}

nav .active::before, .active::after {
    content: '';
	position: absolute;
    bottom: 0;
    left: 0;
	height: 4px;
    width: 65px;
    background-color: var(--primary);
}

nav a:hover:after {
    background-color: var(--nava);
    animation: linear 1s infinite alternate a;
}

nav a:hover {
    padding: 20 px;
    color: var(--secondary);
}

/* Image */

.content {
    background: orange;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    margin: 80px 0;
}

img {
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 5px;
    width: 500px;
}
  
img:hover {
    box-shadow: 0 0 2px 1px rgba(0, 140, 186, 0.5);
}

/* Footer */

footer {
    background-color: var(--footer-background-color);
    color: var(--secondary);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 20px;
}

footer article {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0 200px;
}