style.css

@import url("https://fonts.googleapis.com/css2?family=Poppins&display=swap");

* {
	font-family: "Poppins", sans-serif;
	margin: 0;
	padding: 0;
	user-select: none;
}

body {
	display: flex;
	flex-direction: column;
	justify-content: center;
	align-items: center;
	min-height: 100vh;
	color: #fff;
	background-color: #3e3e3e;
}

#text {
	display: flex;
	flex-direction: column;
	justify-content: center;
	align-items: center;
	border: 2px solid #fff;
	border-radius: 10px;
	padding: 1rem;
}

main {
	display: flex;
	flex-direction: column;
	justify-content: center;
	align-items: center;
	color: #fff;
	background-color: #1e1e1e;
	padding: 2rem;
	margin: 10px 0;
}

#dmy-container {
	display: flex;
	flex-direction: column;
}

#date-container,
#month-container,
#year-container {
	color: #fff;
	padding: 20px 50px;
}

#date-dd,
#month-dd,
#year-ip {
	width: 120px;
	text-align: center;
	outline: none;
}

#date-dd,
#year-ip {
	margin-left: 45px;
}

#month-dd {
	margin-left: 33px;
}

.button {
	color: #fff;
	background-color: transparent;
	border: 2px solid #fff;
	border-radius: 10px;
	padding: 7px 12px;
	cursor: pointer;
}

#day-button:hover {
	background-color: #3e3e3e;
	transition: 1s;
}

#reset-button {
	background-color: #f00;
}

#result {
	display: none;
	background-color: #3e3e3e;
	border: 2px solid #fff;
	border-radius: 10px;
	margin: 20px;
	padding: 10px;
}

#date-span,
#day {
	font-weight: bold;
	text-decoration: underline;
}