/*
 * Styles for every page of the Spacelab site.
 *
 * Shares its look with tjo.is (site.css in tusharjois.github.io), but this site is
 * dark-only so the starfield drawn by stars.js always shows.
 *
 * Colors: Nord (https://www.nordtheme.com). Type: Inter (https://rsms.me/inter/).
 */

/* ---------- Tokens ---------- */

:root {
    /* Nord: Polar Night (0-3), Snow Storm (4-6), Frost (7-10), Aurora (11-15) */
    --nord0: #2e3440;
    --nord1: #3b4252;
    --nord2: #434c5e;
    --nord4: #d8dee9;
    --nord6: #eceff4;
    --nord7: #8fbcbb;
    --nord8: #88c0d0;
    --nord10: #5e81ac;
    --nord14: #a3be8c;

    --bg: var(--nord0);
    --surface: var(--nord1);
    --border: var(--nord2);
    --text: var(--nord6);
    --muted: var(--nord4);
    --link: var(--nord8);
    --accent: var(--nord10);
    --header-bg: rgb(46 52 64 / 0.85);

    --header-h: 3.75rem;
    color-scheme: dark;
}

/* ---------- Base ---------- */

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    font-family: Inter, sans-serif;
    font-feature-settings: 'liga' 1, 'calt' 1;
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

@supports (font-variation-settings: normal) {
    html {
        font-family: InterVariable, sans-serif;
    }
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    letter-spacing: -0.011em;
}

a {
    color: var(--link);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
    text-underline-offset: 0.15em;
}

a:focus-visible {
    outline: 2px solid var(--link);
    outline-offset: 2px;
    border-radius: 2px;
}

h1,
h2,
h3,
h4 {
    letter-spacing: -0.022em;
    line-height: 1.25;
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    margin: 0 0 0.75rem;
}

h2 {
    font-size: 1.25rem;
    font-weight: 650;
    margin: 2.75rem 0 1rem;
}

h3 {
    font-size: 1rem;
    font-weight: 600;
    margin: 0;
}

h4 {
    font-size: 0.9375rem;
    font-weight: 600;
    margin: 0;
}

p {
    margin: 0 0 1rem;
}

code {
    font-family: 'Fira Code', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.875em;
    padding: 0.1em 0.35em;
    border-radius: 0.25rem;
    background: var(--surface);
}

hr {
    margin: 2.5rem 0;
    border: 0;
    border-top: 1px solid var(--border);
}

[id] {
    scroll-margin-top: calc(var(--header-h) + 1rem);
}

.wrap {
    max-width: 52.5rem;
    margin: 0 auto;
    padding-inline: 1.25rem;
}

/* Hidden on screen, still read by screen readers and search engines. */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
}

.skip {
    position: absolute;
    left: -999px;
}

.skip:focus {
    left: 1rem;
    top: 0.75rem;
    z-index: 20;
    padding: 0.5rem 0.75rem;
    border-radius: 0.5rem;
    background: var(--bg);
}

/* ---------- Starfield ---------- */

/* Drawn by stars.js. Fixed behind the page, sized to the largest viewport so mobile toolbars don't stretch it. */
.starfield {
    position: fixed;
    top: 0;
    left: 0;
    z-index: -1;
    width: 100%;
    height: 100vh;
    height: 100lvh;
    pointer-events: none;
}

/* ---------- Header ---------- */

.site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: var(--header-bg);
    -webkit-backdrop-filter: saturate(180%) blur(8px);
    backdrop-filter: saturate(180%) blur(8px);
    border-bottom: 1px solid var(--border);
}

.site-header .wrap {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 0.25rem 2rem;
    min-height: var(--header-h);
    padding-block: 0.75rem;
}

.site-name {
    color: var(--text);
    font-size: 1.375rem;
    font-weight: 700;
    letter-spacing: -0.022em;
}

/* Homepage: keep the name's space in the header without showing it. */
.site-name.placeholder {
    visibility: hidden;
}

/* The period in "Spacelab." */
.dot {
    color: var(--link);
    font-weight: 900;
}

.site-header ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem 1.25rem;
    margin: 0;
    padding: 0;
    list-style: none;
    font-size: 0.9375rem;
}

.site-header nav a {
    color: var(--muted);
}

.site-header a:hover {
    color: var(--link);
    text-decoration: none;
}

.site-header a[aria-current] {
    color: var(--text);
}

.site-header nav a[aria-current] {
    font-weight: 600;
    text-decoration: underline 2px var(--link);
    text-underline-offset: 0.45em;
}

/* ---------- Page furniture ---------- */

main.wrap {
    padding-block: 3rem 4rem;
}

.lede {
    color: var(--muted);
    font-size: 1.0625rem;
}

.callout {
    padding: 0.75rem 1rem;
    border-left: 3px solid var(--accent);
    border-radius: 0 0.5rem 0.5rem 0;
    background: var(--surface);
}

.note {
    color: var(--muted);
    font-size: 0.875rem;
    font-style: italic;
}

/* Pill-shaped links: hero links, publication links, course offerings. */
.pills,
.links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.pills a,
.links a {
    display: inline-block;
    padding: 0.3em 0.85em;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--surface);
    color: var(--text);
    font-size: 0.875rem;
    line-height: 1.4;
}

.pills a:hover,
.links a:hover {
    border-color: var(--link);
    color: var(--link);
    text-decoration: none;
}

/* Long-form pages: /people/join/, /research/amigo/. */
.prose li + li {
    margin-top: 0.5rem;
}

.prose h3 {
    margin: 2rem 0 0.5rem;
}

/* ---------- Home ---------- */

/*
 * Desktop: the lab photo floats right, so the name, tagline, links, and intro paragraph wrap around it.
 * Mobile: one column, with the photo moved down above the logo (see the small-screens block).
 */
.home > .photo {
    float: right;
    width: 17rem;
    margin: 0 0 1.5rem 2.5rem;
}

.home > .hero {
    margin-bottom: 2.5rem;
}

/* Everything after the intro paragraph starts below the photo. */
.home .callout {
    clear: right;
}

.hero h1 {
    font-size: 2.5rem;
    margin: 0;
}

.tagline {
    margin: 0.25rem 0 0;
    color: var(--muted);
    font-size: 1.125rem;
}

.tagline .org {
    display: block;
}

.hero .pills {
    margin-top: 1.25rem;
}

address {
    font-style: normal;
}

.photo {
    margin: 0;
}

.photo img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: 0.75rem;
}

.photo figcaption {
    margin-top: 0.6rem;
    color: var(--muted);
    font-size: 0.875rem;
    font-style: italic;
    text-align: center;
}

/* The rocket logo that closes the homepage. */
.emblem {
    display: block;
    clear: both;
    margin: 3rem auto 0;
    width: 112px;
    height: 112px;
    border-radius: 50%;
}

/* ---------- People ---------- */

.people {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(min(100%, 22rem), 1fr));
    gap: 0.75rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

/* Photo on the left, name and details on the right, email along the bottom. */
.person {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: center;
    gap: 0.85rem 1.1rem;
    padding: 1rem 1.1rem;
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    background: var(--surface);
}

.person h3,
.person h4 {
    margin-bottom: 0.2rem;
    font-size: 1.0625rem;
}

.person p {
    margin: 0;
    font-size: 0.875rem;
}

.person .role {
    color: var(--muted);
    font-style: italic;
}

.person .email {
    grid-column: 1 / -1;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border);
}

/* A long address breaks after "(at)" rather than mid-domain. */
.person .email span {
    display: inline-block;
}

.avatar {
    display: block;
    width: 88px;
    height: 88px;
    border-radius: 50%;
    object-fit: cover;
}

/* Stand-in for someone without a photo yet. */
.avatar.initials {
    display: grid;
    place-items: center;
    background: var(--border);
    color: var(--muted);
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: 0;
}

/* Alumni: one per row, with a bigger photo and a short list of facts. */
.people.wide {
    grid-template-columns: minmax(0, 1fr);
}

.wide .avatar {
    width: 128px;
    height: 128px;
}

.facts {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    gap: 0.15rem 0.75rem;
    margin: 0.6rem 0 0;
    font-size: 0.875rem;
}

.facts dt {
    font-weight: 600;
}

.facts dd {
    margin: 0;
}

/* Visitors: smaller cards, no photo. */
.people.compact {
    grid-template-columns: repeat(auto-fill, minmax(min(100%, 15rem), 1fr));
}

.compact .person {
    display: block;
    padding: 0.75rem 1rem;
}

.compact .person h4 {
    font-size: 0.9375rem;
}

.compact .person p {
    font-size: 0.8125rem;
}

/* Term headings ("Summer 2025") between visitor lists. */
h3 + .people {
    margin-top: 0.75rem;
}

.people + h3 {
    margin-top: 2rem;
}

/* ---------- Research ---------- */

.jump {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem 1.25rem;
    margin: 0;
    padding: 0;
    list-style: none;
    font-size: 0.9375rem;
}

/* A group of papers, with its year in a sticky left gutter. */
.pub-group {
    display: grid;
    grid-template-columns: 6rem minmax(0, 1fr);
    column-gap: 1.5rem;
    margin-top: 2.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
}

.pub-group > h2 {
    grid-column: 1;
    grid-row: 1 / span 99;
    align-self: start;
    position: sticky;
    top: calc(var(--header-h) + 1.25rem);
    margin: 0;
    padding-top: 0.15rem;
    color: var(--muted);
    font-size: 0.9375rem;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.pub-group > .pub {
    grid-column: 2;
}

.pub {
    margin: 0 -0.75rem 1.25rem;
    padding: 0.5rem 0.75rem;
    border-radius: 0.5rem;
}

.pub:target {
    background: var(--surface);
    box-shadow: inset 3px 0 var(--accent);
}

.pub h3 {
    margin-bottom: 0.3rem;
    font-size: 1.0625rem;
}

.pub p {
    margin: 0;
    font-size: 0.9375rem;
}

/* Past and present lab members in a paper's author list. */
.pub .member {
    text-decoration: underline 1px;
    text-underline-offset: 0.2em;
}

.pub .venue {
    color: var(--muted);
    font-style: italic;
}

.pub .links {
    margin-top: 0.6rem;
    gap: 0.4rem;
}

.pub .links a {
    font-size: 0.8125rem;
}

/* Short venue name or course number, e.g. "CCS '25" or "EE 469". */
.tag {
    display: inline-block;
    margin-right: 0.45em;
    padding: 0.05em 0.5em;
    border: 1px solid var(--border);
    border-radius: 0.3rem;
    background: var(--surface);
    color: var(--text);
    font-size: 0.75rem;
    font-style: normal;
    font-weight: 600;
    letter-spacing: 0;
    vertical-align: 0.1em;
    white-space: nowrap;
}

/* "Artifact reproduced" and similar badges in a paper's link list. */
.links a.badge {
    border-color: var(--nord14);
    background: rgb(163 190 140 / 0.18);
}

/* ---------- Teaching ---------- */

.course {
    margin-top: 2.5rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.course h2 {
    margin: 0 0 0.4rem;
}

.course .venue {
    margin-bottom: 0.75rem;
    color: var(--muted);
    font-size: 0.9375rem;
}

.offered {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem 0.75rem;
}

.offered > span {
    color: var(--muted);
    font-size: 0.875rem;
}

/* ---------- Project pages (/research/<project>/) ---------- */

/* Project name and subtitle with its logo centered beside them. */
.project-head {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.project-head h1 {
    margin: 0;
    color: var(--link);
    font-size: 2.5rem;
}

.project-head .subtitle {
    margin: 0.35rem 0 0;
    color: var(--link);
    font-size: 1.25rem;
    font-weight: 650;
    letter-spacing: -0.022em;
    line-height: 1.3;
}

.project-head .logo {
    display: block;
    width: 112px;
    height: 112px;
}

/* Amigo's own accent color for its title and intro. */
.amigo {
    --link: var(--nord7);
}

.figure {
    display: block;
    max-width: min(100%, 40rem);
    height: auto;
    margin: 2rem auto;
    border-radius: 0.5rem;
}

.wordmark {
    display: block;
    width: min(50%, 18rem);
    height: auto;
    margin: 3rem auto 0;
}

/* ---------- Small screens ---------- */

@media (max-width: 640px) {
    .site-header {
        position: static;
    }

    main.wrap {
        padding-top: 2rem;
    }

    .home {
        display: grid;
        grid-template-columns: minmax(0, 1fr);
        grid-template-areas:
            "hero"
            "body"
            "photo"
            "emblem";
        gap: 2rem;
    }

    .home > .hero {
        grid-area: hero;
        margin: 0;
    }

    .home > .home-body {
        grid-area: body;
    }

    .home > .photo {
        grid-area: photo;
        float: none;
        width: auto;
        margin: 0;
    }

    .home > .emblem {
        grid-area: emblem;
        margin: 0 auto;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .tagline {
        font-size: 1rem;
    }

    .emblem {
        width: 88px;
        height: 88px;
    }

    .avatar {
        width: 72px;
        height: 72px;
    }

    .wide .avatar {
        width: 88px;
        height: 88px;
    }

    .pub-group {
        display: block;
    }

    .pub-group > h2 {
        position: static;
        margin-bottom: 1rem;
    }

    .project-head h1 {
        font-size: 2rem;
    }

    .project-head .logo {
        width: 72px;
        height: 72px;
    }
}

/* ---------- Print ---------- */

/* Browsers drop dark backgrounds when printing, so switch to dark text on white. */
@media print {
    :root {
        --bg: #fff;
        --surface: #fff;
        --border: #ccc;
        --text: #000;
        --muted: #333;
        --link: var(--nord10);
        color-scheme: light;
    }

    .site-header,
    .skip,
    .jump,
    .starfield {
        display: none;
    }

    .pub,
    .person {
        break-inside: avoid;
    }
}