style.css

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    margin: 0px;
    padding: 0px;
    line-height: 1.5;
    background-color: lavender;
}

nav {
    margin: 10px auto;
    padding: 0px 25px;
    border: 1px solid black;
    border-radius: 1000px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: white;
    width: 400px;
    -webkit-box-shadow: 0px 0px 20px 0px rgba(0,0,0,0.4);
-moz-box-shadow: 0px 0px 20px 0px rgba(0,0,0,0.4);
box-shadow: 0px 0px 20px 0px rgba(0,0,0,0.4);
}

.nav-links {
    display: flex;
    align-items: center;
    justify-content: space-evenly;
}

li,
ul {
    list-style: none;
}

h4,
button {
    margin: 10px 0px;
}

p {
    font-size: 14px;
}

.container {
    text-align: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: white;
    padding: 5px 20px;
    border-radius: 15px;
    border: 1px solid black;
    width: 200px;
    -webkit-box-shadow: 0px 0px 20px 0px rgba(0,0,0,0.4);
-moz-box-shadow: 0px 0px 20px 0px rgba(0,0,0,0.4);
box-shadow: 0px 0px 20px 0px rgba(0,0,0,0.4);
}

button {
    padding: 5px 10px;
    background-color: white;
    font-family: inherit;
    border: 1px solid black;
    border-radius: 15px;
}

button:hover {
    background-color: #D2D2D2;
    cursor: pointer;
}

hr {
    display: block;
    height: 1px;
    border: 0;
    border-top: 1px solid black;
    margin: 10px 0;
    padding: 0;
}

#content {
    width: 600px;
    margin: 50px auto;
}

/* unvisited link */
a:link {
    color: black;
}

/* visited link */
a:visited {
    color: black;
}

/* mouse over link */
a:hover {
    color: blue;
}

/* selected link */
a:active {
    color: blue;
}

a:link {
    text-decoration: none;
}

a:visited {
    text-decoration: none;
}

a:hover {
    text-decoration: none;
    cursor: pointer;
}

a:active {
    text-decoration: none;
}