body {
    font-family: "Raleway", sans-serif;
    font-weight: 400;
    font-style: normal;
    color: var(--main-text, black);
    width: 90%;
    max-width: 960px;
    min-width: 320px;
    margin: auto;
    font-size: 16px;
}

/* longhand margin, padding, border */
header {
    position: relative;
    background-color: #eff6ff;
    background-color: color-mix(in srgb, white 70%, lightblue 30%);
    margin-top: 1px;
    margin-bottom: 5px;
    margin-left: 10px;
    margin-right: 10px;
    padding-top: 1px;
    padding-right: 1rem;
    padding-bottom: 1rem;
    padding-left: 1rem;
    border-style: solid;
    border-width: 2px;
    border-radius: 12px;
    text-align: center;
}

h1 {
    color: hsl(210, 100%, 50%);
    text-decoration: underline;
    margin-bottom: 0.5em;
}

h3 {
    font-size: 12pt;
}

strong {
    color: orange;
}

/* shorthand margin, padding, border */
section {
    margin: 1rem 0.5rem 1rem 0.5rem;
    padding: 1rem 1.25rem 1rem 1.25rem;
    border: 2px solid #94a3b8;
    border-radius: 10px;
    background-color: #eff6ff;
    background-color: color-mix(in srgb, white 70%, lightblue 30%);
}

/* wider-gamut color() */
#misc summary {
    color: #1d4ed8;
    color: color(display-p3 0.15 0.40 0.90);
}

nav a {
    display: inline-block;
    margin: 0.25rem;
    padding: 0.3rem 0.6rem;
    color: var(--main-text, black);
    border-radius: 8px;
}

nav a:hover,
button:hover {
    background-color: hsla(210, 80%, 55%, 0.18);
}

nav a:active,
button:active {
    background-color: rgba(0, 140, 255, 0.25);
}

span {
    display: inline;
}

label {
    display: inline-block;
    margin-bottom: 0.35rem;
}

.hidden {
    display: none;
}

.title {
    position: relative;
    top: 2px;
    right: 2px;
    background-color: #dbeafe;
    background-color: color-mix(in srgb, white 75%, skyblue 25%);
    padding: 4px 8px;
    border: 1px solid #93c5fd;
    border-radius: 999px;
}

img,
audio,
video {
    display: block;
    width: 100%;
    max-width: 500px;
    min-width: 220px;
    margin: auto;
}

video {
    height: auto;
}

textarea {
    width: 80%;
    height: 120px;
}

/* Flexbox */
.attendance {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    list-style-position: inside;
    width: 12cm;
}

/* Grid */
.agenda {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    justify-items: stretch;
}

footer {
    position: static;
    text-align: center;
}

:root {
    --main-text: #1f2937;
    --card-bg: #ffffff;
}

/* Responsive design */
@media screen and (max-width: 700px) {
    body {
        width: 95%;
    }

    .attendance {
        flex-direction: column;
        align-items: flex-start;
    }

    .agenda {
        grid-template-columns: 1fr;
    }

    nav a {
        display: block;
    }
}

/* Universal Selector (*) */
* {
    box-sizing: border-box;
}

/* Class Selector (.class) */
.hidden {
    display: none;
}

/* ID Selector (#id) */
#attendance {
    background-color: #f8fbff;
}

/* Element Selector (element) */
summary {
    cursor: pointer;
}

/* Attribute Selector ([attribute=foo]) */
input[type="text"] {
    border: 2px solid #93c5fd;
}

/* Pseudo-class Selector (e.g. p:hover) */
summary:hover {
    color: #2563eb;
}

/* Selector List (element, element) */
h1, h2 {
    letter-spacing: 0.5px;
}

/* Descendant Combinator (element element) */
section ul {
    padding-left: 1.5rem;
}

/* Child Combinator (element > element) */
nav > a {
    font-weight: 600;
}

/* General sibling combinator (element ~ element) */
h1 ~ h3 {
    font-style: italic;
}

/* Adjacent sibling combinator (element + element) */
h1 + h2 {
    margin-top: 0.5rem;
}

/* Combining Two Selectors (element.class) */
ul.attendance {
    border-top: 2px dashed #cbd5e1;
    padding-top: 0.5rem;
}

/* New Selector :has() */
section:has(img) {
    box-shadow: 0 0 0 3px #dbeafe;
}

/* Nested Selectors */
header {
    & nav {
        margin-top: 0.5rem;
    }

    & p {
        font-size: 0.95rem;
    }
}