style.css

@import url('https://fonts.googleapis.com/css2?family=Quicksand:wght@400;500;600;700&display=swap');

:root {
	--color-accent: rgb(112, 71, 235);
	--color-accent: #3099f0;
	--background-color: #F8F7FA;
	--foreground-color:  #FFFFFF;
	--text-color: #19181A;
	--highlight-text-color: var(--text-color);
	--active-text-color: #F8F7FA;
	--inactive-text-color: #A5A5A5;
	--btn-bg: #F8F7FA;
	--box-shadow: #EFEFEF;

	--border-width: 1px;
	--border-radius: 15px;
	--spacing: 18px;
}

@media	(prefers-color-scheme: dark){
	:root{
		--background-color: #19181A;
		--foreground-color:  #282729;
		--text-color: #C9C8CC;
		--highlight-text-color: #F8F7FA;
		--inactive-text-color: #68676A;
		--btn-bg: #313133;
		--box-shadow: #111111;
	}
}

* {
	margin: 0;
	padding: 0;
}

body {
	height: 100vh;
	background: var(--background-color);
	display: flex;
	justify-content: center;
	align-items: center;
	font-family: 'Quicksand', sans-serif;
	user-select: none;
}

/* ----------card---------- */

.card {
	width: 316px;
	height: fit-content;
	background-color: var(--foreground-color);
	border-radius: var(--border-radius);
	box-shadow: 0px 0px 10px var(--box-shadow);
	margin:20px;
}

/* ----------calendar ---------- */

.calendar-toolbar {
	display: flex;
	justify-content: space-between;
	align-items: center;
	padding: 20px;
	padding-bottom: 15px;
}

.calendar-toolbar > .current-month{
	font-size: 20px;
	font-weight: bold;
	color: var(--highlight-text-color);
}

.btn{
	background: var(--btn-bg);
	border: none;
	border-radius: var(--border-radius);
	padding: 11px 15.5px;
	color: var(--highlight-text-color);
	font-family: 'Quicksand', sans-serif;
	font-weight: 600;
	font-size: 0.9rem;
	margin-right: 1px;
	box-shadow: 0px 0px 0px var(--box-shadow);
}

.weekdays,
.calendar-days{
	display: flex;
	flex-wrap: wrap;
	padding-inline: var(--spacing);
}
.weekdays{
	padding-top: 12px;
}
.calendar-days{
	padding-bottom: 12px;
}

.weekday-name,
[class$='-day']{
    width: 40px;
    height: 40px;
	color: var(--text-color);
    text-align: center;
	line-height: 40px;
	font-weight: 500;
	font-size: 1rem;
}

.weekday-name{
	color: var(--highlight-text-color);
    font-weight: 700;
}

.current-day{
	background-color: var(--color-accent);
	color: var(--active-text-color); 
	border-radius: var(--border-radius);
	font-weight: 700;
	transition: .5s;
	cursor: pointer;
}

.padding-day{
	color: var(--inactive-text-color);
	user-select: none;
}

.btn:hover,
.month-day:hover{
	border-radius: var(--border-radius);
	background-color: var(--btn-bg);
	color: var(--color-accent);
	border-radius: var(--border-radius);
	transition: .1s;
	cursor: pointer;
	box-shadow: inset 0px 0px 0px 1.5px var(--color-accent);
}

.btn:focus,
.month-day:focus{
	border-radius: var(--border-radius);
	background-color: var(--color-accent);
	color: var(--active-text-color);
}

.goto-buttons{
	padding-block: 18px;
	display: flex;
	justify-content: space-evenly;
}

.border-top{
	border-top: var(--border-width) solid var(--box-shadow);
}