/* ==========================================================================
   Yi Ding — academic homepage
   EB Garamond reading type, JetBrains Mono metadata, restrained sans headings,
   and a handwritten name and signature. Faint personal tags inhabit the margins.
   ========================================================================== */

:root {
    --page-width: 960px;
    --page-inline-space: 3rem;
    --topbar-height: 72px;
    --trail-height: 118px;
    --stage-width: 64px;

    --font-sans: "Manrope", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", sans-serif;
    --font-serif: "EB Garamond", Georgia, "Songti SC", "Times New Roman", serif;
    --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    /* Ships a single weight (400). Display type asks for 700 anyway and lets the
       browser synthesise the bold — deliberate, so `font-synthesis-weight` must
       stay at its default (never set it to `none`, that silently kills this).
       Its cap-height runs ~17% taller and its descenders ~41% deeper than a
       typical script face, so hand-font sizes are set smaller and line-heights
       looser than usual. */
    --font-hand: "Annie Use Your Telescope", "Bradley Hand", "Segoe Script", cursive;

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;

    --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

:root,
:root[data-theme="light"] {
    --bg: #fbfbfd;
    --bg-elev: #ffffff;
    --bg-sunk: #f3f4f8;
    --ink: #15161c;
    --ink-soft: #555a68;
    --ink-faint: #626774;
    --rule: #e1e3ea;
    --rule-soft: #edeef3;
    --accent: #3f4fa8;
    --accent-hover: #33418d;
    --accent-wash: #ecedfa;
    --badge-ink: #805000;
    --badge-bg: #fff3ce;
    --badge-border: #e6c776;
    --shadow: 0 1px 2px rgba(21, 22, 28, 0.05), 0 10px 28px -18px rgba(21, 22, 28, 0.35);
}

:root[data-theme="dark"] {
    --bg: #121315;
    --bg-elev: #191a1d;
    --bg-sunk: #0b0c0f;
    --ink: #e8e9ee;
    --ink-soft: #9ba1b0;
    --ink-faint: #9296a0;
    --rule: #282b34;
    --rule-soft: #1e2027;
    --accent: #9aa6f0;
    --accent-hover: #b3bcf5;
    --accent-wash: #212540;
    --badge-ink: #f6d680;
    --badge-bg: #302714;
    --badge-border: #756030;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.45), 0 10px 28px -18px rgba(0, 0, 0, 0.85);
}

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

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--topbar-height) + 24px);
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: var(--font-serif);
    font-size: 1.1875rem;
    line-height: 1.66;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
}

a {
    color: var(--accent);
    text-decoration: none;
    text-underline-offset: 3px;
    transition: color 140ms var(--ease);
}

a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
    text-decoration-thickness: 1px;
}

p {
    margin: 0 0 0.85em;
}

h1,
h2,
h3 {
    margin: 0;
    font-weight: 600;
    line-height: 1.25;
    text-wrap: balance;
}

p {
    text-wrap: pretty;
}

::selection {
    background: var(--accent-wash);
    color: var(--ink);
}

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
    border-radius: 3px;
}

.muted {
    color: var(--ink-faint);
}

.skip-link {
    position: absolute;
    inset-block-start: -100px;
    inset-inline-start: 12px;
    z-index: 100;
    padding: 0.5rem 0.9rem;
    border-radius: var(--radius-sm);
    background: var(--accent);
    color: #fff;
    font-family: var(--font-mono);
    font-size: 0.8rem;
}

.skip-link:focus {
    inset-block-start: 12px;
}

/* --------------------------------------------------------------------------
   Top bar
   -------------------------------------------------------------------------- */

.topbar {
    position: sticky;
    inset-block-start: 0;
    z-index: 3;
    border-block-end: 1px solid transparent;
    background: var(--bg);
    transition: border-color 200ms var(--ease);
}

.topbar.is-stuck {
    border-block-end-color: var(--rule-soft);
}

.topbar-inner {
    display: flex;
    align-items: center;
    gap: 2.5rem;
    width: min(100% - var(--page-inline-space), var(--page-width));
    height: var(--topbar-height);
    margin-inline: auto;
}

.topbar-name {
    flex-shrink: 0;
    color: var(--ink);
    font-family: var(--font-hand);
    font-size: 1.42rem;
    font-weight: 700;
    line-height: 1.2;
}

.topbar-name:hover {
    color: var(--accent);
    text-decoration: none;
}

.topbar-nav {
    flex: 1;
    min-width: 0;
}

.topbar-controls {
    display: flex;
    align-items: center;
    flex-shrink: 0;
    gap: 0.25rem;
}

.nav-links {
    display: flex;
    gap: 1.35rem;
    margin: 0;
    padding: 0;
    overflow-x: auto;
    list-style: none;
    scrollbar-width: none;
}

.nav-links::-webkit-scrollbar {
    display: none;
}

.nav-links a {
    position: relative;
    display: block;
    padding-block: 8px;
    color: var(--ink-soft);
    font-family: var(--font-mono);
    font-size: 0.79rem;
    font-weight: 500;
    white-space: nowrap;
}

.nav-links a::after {
    position: absolute;
    inset-block-end: 3px;
    inset-inline-start: 0;
    width: 100%;
    height: 1.5px;
    border-radius: 2px;
    background: var(--accent);
    content: "";
    transform: scaleX(0);
    transform-origin: 0 50%;
    transition: transform 220ms var(--ease);
}

.nav-links a:hover {
    color: var(--ink);
    text-decoration: none;
}

.nav-links a.active {
    color: var(--ink);
}

.nav-links a.active::after {
    transform: scaleX(1);
}

.theme-toggle {
    display: grid;
    flex-shrink: 0;
    place-items: center;
    width: 40px;
    height: 40px;
    padding: 0;
    border: 0;
    border-radius: 50%;
    background: transparent;
    color: var(--ink-soft);
    font-size: 0.76rem;
    cursor: pointer;
    transition: color 160ms var(--ease), border-color 160ms var(--ease),
        background-color 160ms var(--ease);
}

.theme-toggle:hover {
    border-color: var(--accent);
    background: var(--accent-wash);
    color: var(--accent);
}

/* --------------------------------------------------------------------------
   Page shell
   -------------------------------------------------------------------------- */

/* Quiet signatures occupy the perimeter, clear of the reading column. */
.ambient-tags {
    --column: min(100% - var(--page-inline-space), var(--page-width));
    --gutter-end: calc(50% - var(--column) / 2);
    --gutter-start: calc(50% + var(--column) / 2);

    position: fixed;
    z-index: 0;
    inset: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    pointer-events: none;
    user-select: none;
    color: var(--ink);
    mask-image: linear-gradient(
        to right,
        #000 0,
        #000 calc(var(--gutter-end) - 32px),
        transparent var(--gutter-end),
        transparent var(--gutter-start),
        #000 calc(var(--gutter-start) + 32px),
        #000 100%
    );
    -webkit-mask-image: linear-gradient(
        to right,
        #000 0,
        #000 calc(var(--gutter-end) - 32px),
        transparent var(--gutter-end),
        transparent var(--gutter-start),
        #000 calc(var(--gutter-start) + 32px),
        #000 100%
    );
}

.ambient-tag {
    position: absolute;
    left: var(--tag-x);
    top: var(--tag-y);
    font-family: var(--tag-font), var(--font-hand);
    font-size: var(--tag-size);
    font-weight: 400;
    line-height: 1.4;
    white-space: nowrap;
    transform: translate(-50%, -50%) rotate(var(--tag-angle));
    opacity: var(--tag-opacity);
    animation: tag-presence var(--tag-duration) linear infinite;
    animation-delay: var(--tag-delay);
}

/* Only opacity changes. Each signature stays still until it is fully invisible. */
@keyframes tag-presence {
    0%, 84%, 100% { opacity: 0; }
    18%, 46% { opacity: var(--tag-opacity); }
}

.ambient-tags.is-paused .ambient-tag { animation-play-state: paused; }
.ambient-tags.is-static .ambient-tag { animation: none; }

.ambient-toggle {
    position: fixed;
    z-index: 2;
    inset-inline-end: 24px;
    inset-block-end: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: 1px solid var(--rule);
    border-radius: 50%;
    background: var(--bg);
    color: var(--ink-soft);
    cursor: pointer;
}

.ambient-toggle[hidden] { display: none; }

.ambient-toggle-icon {
    width: 8px;
    height: 10px;
    border-inline: 2px solid currentColor;
}

.ambient-toggle[aria-pressed="true"] .ambient-toggle-icon {
    width: 0;
    height: 0;
    border: 5px solid transparent;
    border-inline-end: 0;
    border-inline-start: 8px solid currentColor;
}

.ambient-toggle-label {
    position: absolute;
    inset-inline-end: calc(100% + 10px);
    padding: 5px 10px;
    border-radius: 4px;
    background: var(--bg);
    color: var(--ink-soft);
    font-family: var(--font-sans);
    font-size: 0.72rem;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity 160ms var(--ease);
}

.ambient-toggle:hover .ambient-toggle-label,
.ambient-toggle:focus-visible .ambient-toggle-label { opacity: 1; }

.page {
    position: relative;
    z-index: 1;
    width: min(100% - var(--page-inline-space), var(--page-width));
    margin-inline: auto;
    padding-block-end: calc(var(--trail-height) + 1.5rem);
}

/* --------------------------------------------------------------------------
   Hero
   -------------------------------------------------------------------------- */

.hero {
    display: flex;
    align-items: center;
    gap: clamp(1.5rem, 5vw, 3rem);
    padding-block: clamp(3.5rem, 8vw, 7rem) clamp(1.5rem, 3vw, 3rem);
}

.hero-text {
    flex: 1;
    min-width: 0;
}

.hero-name {
    font-family: var(--font-hand);
    font-size: clamp(3.4rem, 8vw, 5rem);
    font-weight: 700;
    line-height: 1.16;
    letter-spacing: 0.005em;
}

.hero-name-cn {
    margin-inline-start: 0.4rem;
    color: var(--ink-soft);
    font-family: var(--font-serif);
    font-size: 0.28em;
    font-weight: 400;
    letter-spacing: 0.02em;
}

.hero-role {
    margin-block: 0.75rem 0;
    color: var(--ink-soft);
    font-family: var(--font-mono);
    font-size: 0.83rem;
    line-height: 1.7;
}

.hero-motto {
    margin-block: 0.6rem 0;
    color: var(--ink-faint);
    font-family: var(--font-hand);
    font-size: 1.28rem;
    font-weight: 700;
    line-height: 1.35;
}

.hero-portrait {
    flex-shrink: 0;
    width: clamp(152px, 28vw, 224px);
}

.hero-portrait img {
    display: block;
    width: 100%;
    aspect-ratio: 1;
    border-radius: 8px;
    object-fit: cover;
    transition: transform 650ms var(--ease);
}

.hero-portrait:hover img {
    transform: translateY(-4px) rotate(-1deg);
}

.social-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-block-start: 1.3rem;
}

.social-links a {
    display: grid;
    place-items: center;
    width: 40px;
    height: 40px;
    border: 0;
    border-radius: 50%;
    color: var(--ink-soft);
    font-size: 0.85rem;
    transition: color 160ms var(--ease), border-color 160ms var(--ease),
        background-color 160ms var(--ease), transform 160ms var(--ease);
}

.social-links a:hover {
    border-color: var(--accent);
    background: var(--accent-wash);
    color: var(--accent);
    text-decoration: none;
    transform: translateY(-2px);
}

.social-cv-mark {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 500;
}

/* --------------------------------------------------------------------------
   Trail — pinned to the viewport bottom, doubling as a reading progress bar.
   `--journey-progress` (0…1) is written by initScrollSpy().
   -------------------------------------------------------------------------- */

.trail {
    position: fixed;
    z-index: 2;
    inset-block-end: 0;
    inset-inline: 0;
    height: var(--trail-height);
    pointer-events: none;
    user-select: none;
}

.trail::before {
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, var(--bg) 55%, transparent);
    content: "";
}

/* The walked path is bounded by the reading column, not the viewport. */
.trail-track {
    position: relative;
    width: min(100% - var(--page-inline-space), var(--page-width));
    height: 100%;
    margin-inline: auto;
}

.trail-line {
    position: absolute;
    inset-block-end: 18px;
    inset-inline: 0;
    height: 1.5px;
    background: linear-gradient(
        to right,
        var(--accent) 0 calc(var(--journey-progress, 0) * 100%),
        var(--rule) calc(var(--journey-progress, 0) * 100%) 100%
    );
}

/* Reading progress, sitting under the right end of the path. */
.trail-readout {
    position: absolute;
    inset-block-end: 3px;
    inset-inline-end: 0;
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.6rem;
    letter-spacing: -0.02em;
    line-height: 1;
}

.traveler-stage {
    position: absolute;
    inset-block-end: 19px;
    inset-inline-start: calc(var(--journey-progress, 0) * 100%);
    width: var(--stage-width);
    pointer-events: auto;
    transform: translateX(calc(var(--journey-progress, 0) * -100%));
}

.traveler-walk {
    position: relative;
    aspect-ratio: 1;
    transform-origin: 50% 100%;
}

.traveler-character {
    position: absolute;
    filter: drop-shadow(0 4px 4px rgba(18, 20, 30, 0.16));
}

:root[data-theme="dark"] .traveler-character {
    filter: drop-shadow(0 4px 5px rgba(0, 0, 0, 0.6));
}

.character-sprite {
    position: absolute;
    inset-block-end: 0;
    overflow: hidden;
    opacity: 0;
    contain: layout paint;
    transition: opacity 70ms linear;
}

.character-sprite-sheet {
    display: block;
    width: 800%;
    max-width: none;
    height: 100%;
    transform: translate3d(var(--sprite-offset, 0%), 0, 0);
    will-change: transform;
}

.traveler-person {
    inset-block-end: 0;
    inset-inline-start: 0;
    width: 58%;
    height: 100%;
}

.traveler-cat {
    inset-block-end: 0.5%;
    inset-inline-end: 0;
    width: 66%;
    height: 42%;
}

.sprite-person-walk {
    inset-inline-start: 0;
    height: 100%;
    aspect-ratio: 269 / 519;
    opacity: 1;
}

.sprite-person-phone {
    inset-inline-start: 0;
    height: 100%;
    aspect-ratio: 230 / 424;
}

.sprite-cat-walk {
    inset-inline-end: 0;
    height: 100%;
    aspect-ratio: 301 / 284;
    opacity: 1;
}

.sprite-cat-rest {
    inset-inline-end: 0;
    height: 100%;
    aspect-ratio: 397 / 302;
}

.sprite-cat-roll {
    inset-inline-end: 0;
    height: 85.8%;
    aspect-ratio: 396 / 259;
}

.traveler-stage.is-rest-action .sprite-person-walk,
.traveler-stage.is-rest-action .sprite-cat-walk,
.traveler-stage.is-cat-rolling .sprite-person-walk,
.traveler-stage.is-cat-rolling .sprite-cat-walk {
    opacity: 0;
}

.traveler-stage.is-rest-action .sprite-person-phone,
.traveler-stage.is-rest-action .sprite-cat-rest,
.traveler-stage.is-cat-rolling .sprite-person-phone,
.traveler-stage.is-cat-rolling .sprite-cat-roll {
    opacity: 1;
}

.traveler-stage.is-reversing .traveler-walk {
    transform: scaleX(-1);
}

.phone-flash {
    position: absolute;
    z-index: 8;
    inset-block-start: 34%;
    inset-inline-start: 43%;
    width: 11px;
    height: 11px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 0 0 3px rgba(226, 232, 255, 0.7),
        0 0 14px 7px rgba(238, 242, 255, 0.85);
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.18);
    pointer-events: none;
}

.phone-flash::before,
.phone-flash::after {
    position: absolute;
    inset: 50% auto auto 50%;
    width: 22px;
    height: 2px;
    border-radius: 99px;
    background: rgba(255, 255, 255, 0.94);
    content: "";
    transform: translate(-50%, -50%);
}

.phone-flash::after {
    transform: translate(-50%, -50%) rotate(90deg);
}

.camera-flash-wash {
    position: absolute;
    z-index: 7;
    inset: -30% -40%;
    border-radius: 50%;
    background: radial-gradient(
        circle,
        rgba(240, 244, 255, 0.75),
        rgba(240, 244, 255, 0)
    );
    opacity: 0;
    pointer-events: none;
}

.traveler-stage.is-flashing .phone-flash {
    animation: phone-camera-flash 300ms ease-out both;
}

.traveler-stage.is-flashing .camera-flash-wash {
    animation: camera-flash-wash 260ms ease-out both;
}

.dust {
    position: absolute;
    z-index: -1;
    inset-block-end: 5%;
    width: 7px;
    height: 7px;
    border: 1.5px solid var(--rule);
    border-radius: 50%;
    opacity: 0;
}

.dust-one {
    inset-inline-start: 10%;
}

.dust-two {
    inset-inline-start: 2%;
    width: 5px;
    height: 5px;
}

.traveler-stage:not(.is-walking):not(.is-rest-action):not(.is-cat-rolling) .traveler-person,
.traveler-stage.is-character-resting .traveler-person {
    animation: person-idle-breathe 3.8s ease-in-out infinite;
}

.traveler-stage:not(.is-walking):not(.is-rest-action):not(.is-cat-rolling) .traveler-cat,
.traveler-stage.is-character-resting .traveler-cat {
    animation: cat-idle-breathe 3.15s ease-in-out 480ms infinite;
}

.traveler-stage.is-walking .dust {
    animation: dust-puff 430ms ease-out infinite;
}

.traveler-stage.is-walking .dust-two {
    animation-delay: 170ms;
}

@keyframes person-idle-breathe {
    0%,
    100% { transform: translateY(0) rotate(0); }
    50% { transform: translateY(-1.2%) rotate(0.18deg); }
}

@keyframes cat-idle-breathe {
    0%,
    100% { transform: translateY(0) rotate(0); }
    50% { transform: translateY(-1.8%) rotate(-0.22deg); }
}

@keyframes phone-camera-flash {
    0% { opacity: 0; transform: translate(-50%, -50%) scale(0.18) rotate(0); }
    18% { opacity: 1; transform: translate(-50%, -50%) scale(1.08) rotate(12deg); }
    52% { opacity: 0.74; transform: translate(-50%, -50%) scale(0.82) rotate(26deg); }
    100% { opacity: 0; transform: translate(-50%, -50%) scale(1.7) rotate(36deg); }
}

@keyframes camera-flash-wash {
    0%,
    100% { opacity: 0; }
    12% { opacity: 0.55; }
    42% { opacity: 0.16; }
}

@keyframes dust-puff {
    0% { opacity: 0; transform: translate(3px, 0) scale(0.45); }
    38% { opacity: 0.55; }
    100% { opacity: 0; transform: translate(-15px, -8px) scale(1.1); }
}

/* --------------------------------------------------------------------------
   Sections
   -------------------------------------------------------------------------- */

.section {
    padding-block: clamp(2.75rem, 6vw, 4.5rem) 0;
}

.section-title {
    display: flex;
    align-items: baseline;
    gap: 0.8rem;
    margin-block-end: 1.65rem;
    font-family: var(--font-sans);
    font-size: clamp(1.25rem, 2.5vw, 1.5rem);
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: -0.03em;
}

.section-title::after {
    content: none;
}

.section-note {
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 400;
}

.prose p:last-child {
    margin-block-end: 0;
}

.prose { width: 100%; }

.prose strong {
    font-weight: 600;
}

.inline-logo {
    height: 0.95em;
    vertical-align: -0.1em;
}

:root[data-theme="dark"] .inline-logo[src$="purdue.svg"] {
    filter: brightness(0) invert(0.9);
}

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

.research-list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
    margin: 0;
    padding: 0;
    list-style: none;
}

.research-list li {
    padding-block-start: 1.2rem;
    border-block-start: 1px solid var(--rule);
}

.interest-keyword {
    display: block;
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 600;
    line-height: 1.3;
}

.research-list p {
    margin-block: 0.6rem 0;
    color: var(--ink-soft);
    font-size: 1.02rem;
    line-height: 1.8;
}

.collab-invite {
    display: flex;
    align-items: baseline;
    gap: 0.6rem;
    margin-block: 1.5rem 0;
    padding: 0;
    color: var(--ink-soft);
    font-size: 1.02rem;
}

.collab-invite i {
    display: none;
}

/* News -------------------------------------------------------------------- */

.news-container {
    max-height: 330px;
    padding-inline-end: 0.5rem;
    overflow-y: auto;
    mask-image: linear-gradient(to bottom, #000 86%, transparent);
    -webkit-mask-image: linear-gradient(to bottom, #000 86%, transparent);
    scrollbar-width: thin;
    scrollbar-color: var(--rule) transparent;
}

.news-container::-webkit-scrollbar {
    width: 5px;
}

.news-container::-webkit-scrollbar-thumb {
    border-radius: 99px;
    background: var(--rule);
}

.news-list {
    margin: 0;
    padding: 0;
    list-style: none;
}

.news-item {
    display: grid;
    grid-template-columns: 5.4rem 1fr;
    gap: 1rem;
    padding-block: 0.45rem;
    border-block-end: 1px solid var(--rule-soft);
}

.news-item:last-child {
    border-block-end: 0;
}

.news-date {
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: -0.02em;
    line-height: 2.1;
    white-space: nowrap;
}

.news-item p {
    margin: 0;
    font-size: 1.04rem;
    line-height: 1.5;
}

/* Publications ------------------------------------------------------------ */

.publication-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 0.35rem 1.5rem;
    margin-block: 0 0.75rem;
    border-block-end: 1px solid var(--rule);
}

.publication-controls[hidden],
.pub[hidden] {
    display: none;
}

.publication-controls button {
    min-height: 44px;
    padding: 0.6rem 0;
    border: 0;
    border-block-end: 2px solid transparent;
    background: transparent;
    color: var(--ink-soft);
    font-family: var(--font-mono);
    font-size: 0.8rem;
    cursor: pointer;
}

.publication-controls button[aria-pressed="true"] {
    border-block-end-color: var(--accent);
    color: var(--accent);
}

.publication-controls button:hover {
    color: var(--accent-hover);
}

.publication-count {
    margin-inline-start: 0.3rem;
    color: var(--ink-faint);
    font-size: 0.72rem;
}

.publication-status {
    margin: 0 0 1.5rem;
    color: var(--ink-soft);
    font-size: 1rem;
}

.publication-list {
    display: grid;
}

.pub {
    display: grid;
    grid-template-columns: 184px 1fr;
    gap: 2rem;
    align-items: start;
    padding-block: 0 2rem;
}

/* Only visible preceding papers add a separator and space above the next row. */
.pub:not([hidden]) ~ .pub {
    padding-block-start: 2rem;
    border-block-start: 1px solid var(--rule-soft);
}

/* Bare figure: fixed width, natural height, no frame or backdrop. */
.pub-thumb img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: 4px;
    transition: transform 650ms var(--ease);
}

.pub:hover .pub-thumb img {
    transform: translateY(-3px);
}

.pub-body {
    min-width: 0;
}

/* Reusable publication distinctions: rankings, Spotlight, Oral, etc.
   Use an anchor when there is a source link; otherwise use a span. */
.pub-meta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.4rem 0.75rem;
}

.pub-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    max-width: 100%;
    padding: 0.24rem 0.6rem;
    border: 1px solid var(--badge-border);
    border-radius: var(--radius-sm);
    background: var(--badge-bg);
    color: var(--badge-ink);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    line-height: 1.65;
}

.pub-badge strong {
    font-weight: 700;
}

.pub-badge time {
    white-space: nowrap;
    font-size: 0.7rem;
}

a.pub-badge:hover {
    color: var(--badge-ink);
    border-color: currentColor;
    text-decoration: underline;
}

a.pub-badge:focus-visible {
    outline: 2px solid var(--badge-ink);
    outline-offset: 3px;
}

.pub-venue {
    display: inline-block;
    color: var(--accent);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.pub-title {
    margin-block: 0.3rem 0;
    font-size: 1.26rem;
    line-height: 1.45;
    letter-spacing: -0.02em;
    text-wrap: pretty;
}

.pub-authors {
    margin-block: 0.32rem 0;
    color: var(--ink-soft);
    font-size: 1rem;
    line-height: 1.75;
}

.highlight-name {
    color: var(--ink);
    font-weight: 600;
}

.pub-tldr {
    margin-block: 0.5rem 0;
    color: var(--ink-soft);
    font-size: 0.99rem;
    line-height: 1.8;
}

.pub-links {
    display: flex;
    flex-wrap: wrap;
    gap: 1.1rem;
    margin-block-start: 0.7rem;
}

.pub-links a {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.4rem 0;
    border: 0;
    color: var(--accent);
    font-family: var(--font-mono);
    font-size: 0.77rem;
    transition: color 160ms var(--ease), border-color 160ms var(--ease),
        background-color 160ms var(--ease);
}

.pub-links a:hover {
    border-color: var(--accent);
    color: var(--accent);
    text-decoration: underline;
}

.pub-links i {
    font-size: 0.64rem;
}

/* GitHub ------------------------------------------------------------------ */

.github-repo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.8rem;
}

.github-repo-card {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    padding: 0.95rem 1.05rem;
    border: 1px solid var(--rule-soft);
    border-radius: var(--radius-md);
    background: var(--bg-elev);
    transition: border-color 200ms var(--ease), transform 200ms var(--ease);
}

.github-repo-card:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.repo-title a {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--ink);
    font-size: 1.1rem;
    font-weight: 600;
    word-break: break-word;
}

.repo-title i {
    color: var(--ink-faint);
    font-size: 0.78rem;
}

.repo-title a:hover {
    color: var(--accent);
    text-decoration: none;
}

.repo-desc {
    flex: 1;
    color: var(--ink-soft);
    font-size: 1rem;
    line-height: 1.45;
}

.repo-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.75rem;
}

.repo-meta span {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
}

.repo-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent);
}

/* Education --------------------------------------------------------------- */

.education-list {
    display: grid;
}

.education-item {
    display: grid;
    grid-template-columns: 1fr 2.5rem;
    gap: 1.1rem;
    align-items: center;
    padding-block: 0.85rem;
    border-block-end: 1px solid var(--rule-soft);
}

.education-item:last-child {
    border-block-end: 0;
}

.edu-year {
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    letter-spacing: -0.02em;
}

.edu-content h3 {
    font-size: 1.14rem;
}

.edu-content p {
    margin: 0.15rem 0 0;
    color: var(--ink-soft);
    font-size: 1rem;
}

.edu-logo img {
    display: block;
    width: 100%;
    max-height: 38px;
    object-fit: contain;
}

/* Services ---------------------------------------------------------------- */

.services {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.7rem;
}

.services-label {
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    text-transform: uppercase;
}

.services-venues {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
}

.venue-tag {
    padding: 0.2rem 0.65rem;
    border: 1px solid var(--rule);
    border-radius: 99px;
    color: var(--ink-soft);
    font-family: var(--font-mono);
    font-size: 0.75rem;
}

/* Footer ------------------------------------------------------------------ */

.site-footer {
    margin-block-start: clamp(2.5rem, 6vw, 3.5rem);
    padding-block-start: 1.35rem;
    border-block-start: 1px solid var(--rule-soft);
    color: var(--ink-faint);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    text-align: center;
}

/* --------------------------------------------------------------------------
   Responsive
   -------------------------------------------------------------------------- */

@media (min-width: 721px) and (max-width: 1100px) {
    :root { --page-inline-space: 8rem; }
}

@media (max-width: 720px) {
    :root {
        --topbar-height: 60px;
        --trail-height: 92px;
        --stage-width: 52px;
    }

    .trail-track {
        width: min(100% - 2rem, var(--page-width));
    }

    /* A few light signatures in the hero; reading sections stay unmarked. */
    .ambient-tags {
        position: absolute;
        height: 380px;
        mask-image: linear-gradient(to bottom, transparent 50px, #000 85px, #000 300px, transparent 100%);
        -webkit-mask-image: linear-gradient(to bottom, transparent 50px, #000 85px, #000 300px, transparent 100%);
    }

    .ambient-tag:nth-child(n + 5) { display: none; }

    .ambient-toggle {
        position: relative;
        inset: auto;
        width: 44px;
        height: 44px;
        border: 0;
        background: transparent;
    }

    .ambient-toggle-label {
        inset-inline-end: 0;
        inset-block-start: calc(100% + 8px);
    }

    .topbar-inner,
    .page {
        width: min(100% - 2rem, var(--page-width));
    }

    .topbar-name {
        display: none;
    }

    .hero {
        flex-direction: column-reverse;
        align-items: flex-start;
        gap: 1.4rem;
    }

    .topbar-inner { gap: 0.5rem; }

    .research-list { grid-template-columns: 1fr; gap: 1.3rem; }

    .nav-links a { min-height: 44px; display: flex; align-items: center; }

    .social-links a,
    .theme-toggle { width: 44px; height: 44px; }

    .pub-links a { min-height: 44px; }

    .trail-line {
        inset-block-end: 15px;
    }

    .traveler-stage {
        inset-block-end: 16px;
    }

    .pub {
        grid-template-columns: 1fr;
        gap: 0.9rem;
    }

    .pub-thumb img {
        max-width: 280px;
    }

    .news-item {
        grid-template-columns: 1fr;
        gap: 0.1rem;
    }

    .news-date {
        line-height: 1.5;
    }

    .education-item {
        grid-template-columns: 1fr 2.2rem;
        gap: 0.6rem 1rem;
    }

    .edu-year {
        grid-column: 1 / -1;
    }
}

@media (prefers-reduced-motion: reduce) {
    .ambient-tag { animation: none !important; }

    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
    }

    .trail,
    .ambient-toggle {
        display: none;
    }

    .page {
        padding-block-end: 2rem;
    }
}

/* Signature ----------------------------------------------------------------
   The calligraphy SVG is used as a mask so it takes the theme's ink colour. */
.signature {
    display: block;
    aspect-ratio: 1495 / 498;
    background-color: currentColor;
    -webkit-mask: url("images/signature.svg") no-repeat left center / contain;
    mask: url("images/signature.svg") no-repeat left center / contain;
}

.topbar-name .signature { height: 34px; }
.hero-name .signature { height: clamp(96px, 15vw, 150px); margin-inline-start: -0.4rem; }
.hero-motto .signature { height: 60px; margin-block-start: 0.2rem; color: var(--ink-soft); }

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
}

/* Themes may decorate the text name/handle; drop that when the signature is used. */
.topbar-name:has(.signature)::after,
.hero-name:has(.signature)::after,
.hero-motto:has(.signature)::after { content: none; }
.hero-motto:has(.signature) { display: block; }

.site-footer .signature {
    height: 40px;
    margin: 0 auto 0.75rem;
    color: var(--ink-faint);
    opacity: 0.55;
    -webkit-mask-position: center;
    mask-position: center;
}

/* Pixel avatar walking the trail -------------------------------------------- */
.traveler-avatar {
    display: block;
    width: 100%;
    height: auto;
    image-rendering: pixelated;
    cursor: grab;
    touch-action: none;
    filter: drop-shadow(0 3px 3px rgba(18, 20, 30, 0.18));
    transform-origin: 50% 100%;
}
:root[data-theme="dark"] .traveler-avatar { filter: drop-shadow(0 3px 4px rgba(0, 0, 0, 0.6)); }
.traveler-stage.is-moving .traveler-avatar { animation: traveler-hop 360ms steps(2) infinite; }
.traveler-stage.is-dragging .traveler-avatar { cursor: grabbing; animation: none; transform: scale(1.06); }
.is-traveler-dragging, .is-traveler-dragging * { cursor: grabbing !important; user-select: none; }
@keyframes traveler-hop { 50% { transform: translateY(-3px); } }
@media (prefers-reduced-motion: reduce) {
    .traveler-stage.is-moving .traveler-avatar { animation: none; }
}