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

body {
    font-family: sans-serif;
    padding: 0 1rem 2rem 1rem;
    max-width: 1200px;
    margin: auto;
    background-color: rgb(245, 245, 245);
}

header {
    padding: 2rem 0;
    margin: auto;
    text-align: center;
}
header a {
    text-decoration: none;
}
header h1 {
    color: gray;
}


nav {
    margin: auto;
    font-family: monospace;
}

.collapsible {
    margin-bottom: 2rem;
}

.collapsible summary {
    padding: 10px 14px;
    cursor: pointer;
    list-style: none;
    text-align: center;
    text-decoration: underline;
}

.collapsible summary::-webkit-details-marker {
    display: none;
}

.collapsible ul {
    margin: 0;
    padding: 0;
    text-align: center;
}

.collapsible li {
    list-style: none;
}

.collapsible a {
    display: block;
    padding: .5rem 0;
    text-decoration: none;
    color: black;
}

.collapsible a:hover {
    text-decoration: underline;
}

.gallery {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
}
.frame {
    aspect-ratio: 1 / 1;
    overflow: hidden;

}
.frame img {
    width: 100%;
    height: 100%;
    object-fit: contain;     /* fully visible, letterboxed */
    object-position: center;
    display: block;
}