/* ======================================================
   ICFM10 Proceedings — Stylesheet (matches program.html design)
   ====================================================== */

/* --- Design tokens (mirrors program.html) --- */
:root {
    --bg: #eef5f7;
    --surface: rgba(255,255,255,0.9);
    --surface-strong: #ffffff;
    --text: #153047;
    --muted: #557085;
    --line: rgba(21,48,71,0.12);
    --brand: #0c5f92;
    --brand-deep: #083b63;
    --sand: #f5efe2;
    --shadow: 0 18px 40px rgba(8,59,99,0.12);
    --radius-lg: 28px;
    --radius-card: 20px;
    --radius-sm: 10px;
    --max-width: 960px;
    --header-height: 60px;
    --transition: .25s ease;
    /* backwards-compat aliases */
    --color-primary: #0c5f92;
    --color-primary-dark: #083b63;
    --color-primary-light: rgba(12,95,146,0.09);
    --color-accent: #0c5f92;
    --color-accent-hover: #083b63;
    --color-surface: #ffffff;
    --color-bg: #eef5f7;
    --color-text: #153047;
    --color-text-secondary: #557085;
    --color-text-muted: #8aabb8;
    --color-border: rgba(21,48,71,0.12);
    --radius-md: 14px;
    --shadow-sm: 0 2px 8px rgba(8,59,99,0.06);
    --shadow-md: 0 8px 24px rgba(8,59,99,0.10);
    --shadow-lg: 0 18px 40px rgba(8,59,99,0.14);
}

/* --- Reset --- */
*,*::before,*::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-height) + 72px); overflow-x: hidden; }
body {
    font-family: "Inter","Source Sans 3",sans-serif;
    background:
        radial-gradient(circle at top left, rgba(12,95,146,0.16), transparent 34%),
        radial-gradient(circle at top right, rgba(227,123,66,0.18), transparent 26%),
        linear-gradient(180deg, #f8fbfc 0%, var(--bg) 48%, #e8f0f3 100%);
    background-attachment: fixed;
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    min-height: 100vh;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }
ul { list-style: none; }
button { cursor: pointer; border: none; background: none; font: inherit; color: inherit; }
input, select { font: inherit; }

/* ============ HEADER ============ */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    background: rgba(238,245,247,0.86);
    border-bottom: 1px solid rgba(21,48,71,0.08);
}
/* Header hidden on landing; shown after Browse Papers is clicked */
.header { display: none; }
body.browsing .header { display: block; }
.header__container {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 16px;
    max-width: var(--max-width);
    margin: 0 auto;
}
.header__logo-link { flex-shrink: 0; }
.header__logo { height: 40px; width: auto; border-radius: 12px; box-shadow: 0 6px 18px rgba(8,59,99,0.10); }
.header__text { flex: 1; min-width: 0; }
.header__title {
    font-family: "Space Grotesk",sans-serif;
    font-size: 1rem;
    font-weight: 700;
    color: var(--brand-deep);
    line-height: 1.15;
    letter-spacing: -0.02em;
}
.header__subtitle {
    font-family: "Inter",sans-serif;
    font-size: .75rem;
    font-weight: 500;
    color: var(--muted);
    margin-top: 1px;
}

/* Hamburger */
.header__menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 6px;
    width: 36px;
}
.header__menu-btn span {
    display: block;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: var(--transition);
}
.header__menu-btn[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.header__menu-btn[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.header__menu-btn[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Nav */
.header__nav {
    display: none;
    flex-direction: column;
    background: rgba(238,245,247,0.96);
    border-top: 1px solid var(--line);
    padding: 8px 16px 14px;
    max-width: var(--max-width);
    margin: 0 auto;
}
.header__nav.open { display: flex; }
.header__nav-link {
    padding: 10px 0;
    font-size: .78rem;
    font-weight: 700;
    font-family: "Space Grotesk",sans-serif;
    color: var(--text);
    border-bottom: 1px solid var(--line);
    letter-spacing: .04em;
    text-transform: uppercase;
}
.header__nav-link:last-child { border-bottom: none; }
.header__nav-link:hover { color: var(--brand); text-decoration: none; }

/* ============ HERO ============ */
.hero-card {
    position: relative;
    overflow: visible;
    min-height: 0;
    margin: 0 auto;
    max-width: var(--max-width);
    padding: 28px 24px 32px;
    border-radius: 0;
    background: transparent;
    box-shadow: none;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 16px;
    isolation: isolate;
}
.hero-card::before,
.hero-card::after { display: none; }

/* Cover image (proceedings title page) */
.hero-card__cover {
    max-width: min(500px, 100%);
    height: auto;
    border-radius: 4px;
    /* clip the image's own thin edge */
    outline: 6px solid var(--bg);
    outline-offset: -1px;
    /* layered CSS frame: inner accent ring + outer soft shadow */
    box-shadow:
        0 0 0 2px var(--brand),
        0 0 0 6px rgba(12,95,146,0.12),
        0 24px 56px rgba(8,59,99,0.22),
        0 6px 18px rgba(8,59,99,0.12);
    display: block;
}

/* Browse Papers + Download CTA below the image */
.hero-card__cta {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    justify-content: center;
    margin-top: 4px;
}
.hero-card__browse {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    min-height: 56px;
    padding: 0 36px;
    border-radius: 999px;
    font-family: "Space Grotesk", sans-serif;
    font-weight: 700;
    font-size: 1.08rem;
    letter-spacing: 0.01em;
    background: linear-gradient(135deg, #1478b8 0%, var(--brand) 50%, var(--brand-deep) 100%);
    color: #ffffff;
    text-decoration: none;
    box-shadow:
        0 4px 18px rgba(12,95,146,0.38),
        inset 0 1px 0 rgba(255,255,255,0.18);
    transition: filter .2s, box-shadow .2s, transform .15s;
}
.hero-card__browse:hover {
    filter: brightness(1.1);
    box-shadow:
        0 8px 28px rgba(12,95,146,0.50),
        inset 0 1px 0 rgba(255,255,255,0.22);
    text-decoration: none;
    color: #fff;
}
.hero-card__browse:active { transform: translateY(0); filter: brightness(0.96); }
.hero-card__download {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    min-height: 56px;
    padding: 0 30px;
    border-radius: 999px;
    font-family: "Space Grotesk", sans-serif;
    font-weight: 700;
    font-size: 1.08rem;
    letter-spacing: 0.01em;
    background: rgba(255,255,255,0.55);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    color: var(--brand-deep);
    border: 2px solid rgba(12,95,146,0.35);
    text-decoration: none;
    box-shadow: 0 2px 12px rgba(12,95,146,0.12);
    transition: background .2s, border-color .2s, color .2s, box-shadow .2s, transform .15s;
}
.hero-card__download:hover {
    background: rgba(12,95,146,0.10);
    border-color: var(--brand);
    color: var(--brand-deep);
    box-shadow: 0 6px 20px rgba(12,95,146,0.22);
    text-decoration: none;
}
.hero-card__download:active { transform: translateY(0); }

@media (max-width: 480px) {
    .hero-card__cta {
        flex-direction: column;
        align-items: stretch;
        width: 100%;
    }
    .hero-card__browse,
    .hero-card__download {
        width: 100%;
        justify-content: center;
        font-size: 1rem;
        padding: 0 20px;
    }
}
.hero-card__dismiss {
    position: absolute;
    top: 12px;
    right: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    padding: 0;
    border: none;
    border-radius: 50%;
    background: rgba(21,48,71,0.08);
    color: var(--muted);
    cursor: pointer;
    transition: background .15s;
}
.hero-card__dismiss:hover {
    background: rgba(21,48,71,0.16);
    color: var(--text);
}
.hero-card--hidden {
    display: none;
}
.footer__show-hero { display: none; }
.header__show-hero {
    display: none;
    padding: 5px 10px;
    border: 1.5px solid rgba(12,95,146,0.30);
    border-radius: 8px;
    background: transparent;
    color: var(--brand-deep);
    font-family: "Space Grotesk",sans-serif;
    font-size: .72rem;
    font-weight: 700;
    letter-spacing: .06em;
    text-transform: uppercase;
    cursor: pointer;
    transition: background .15s, border-color .15s;
    white-space: nowrap;
    flex-shrink: 0;
}
body.browsing .header__show-hero { display: inline-flex; }
.header__show-hero:hover {
    background: rgba(12,95,146,0.08);
    border-color: rgba(12,95,146,0.50);
}
@media (max-width: 479px) {
    .header__subtitle { display: none; }
    .header__show-hero__label { display: none; }
}

/* ============ SEARCH BAR ============ */
.search-bar {
    position: sticky;
    top: var(--header-height);
    z-index: 90;
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    background: rgba(238,245,247,0.92);
    border-bottom: 1px solid rgba(21,48,71,0.08);
    padding: 12px 16px;
    box-shadow: 0 2px 12px rgba(8,59,99,0.06);
}
.search-bar__container { max-width: var(--max-width); margin: 0 auto; }
.search-bar__input-wrap {
    position: relative;
    display: flex;
    align-items: center;
    background: var(--surface-strong);
    border: 1.5px solid var(--line);
    border-radius: var(--radius-sm);
    transition: border-color .18s ease, box-shadow .18s ease;
}
.search-bar__input-wrap:focus-within {
    border-color: rgba(12,95,146,0.40);
    box-shadow: 0 0 0 3px rgba(12,95,146,0.10);
}
.search-bar__icon { width: 18px; height: 18px; margin-left: 12px; color: var(--muted); flex-shrink: 0; }
.search-bar__input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 10px 12px;
    font-size: .97rem;
    font-family: "Inter",sans-serif;
    color: var(--text);
    outline: none;
    min-width: 0;
}
.search-bar__input::placeholder { color: var(--muted); }
.search-bar__input::-webkit-search-cancel-button { -webkit-appearance: none; appearance: none; }
.search-bar__clear {
    padding: 8px 12px;
    font-size: 1rem;
    color: var(--muted);
    transition: color .15s;
}
.search-bar__clear:hover { color: var(--text); }
.search-bar__filters {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
    align-items: center;
}
.search-bar__filter-group {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-wrap: nowrap;
    min-width: 0;
    max-width: 100%;
}
.search-bar__label {
    font-family: "Space Grotesk",sans-serif;
    font-size: .72rem;
    font-weight: 700;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: .08em;
}
.search-bar__check-label {
    display: flex;
    align-items: center;
    gap: 5px;
    font-family: "Space Grotesk",sans-serif;
    font-size: .72rem;
    font-weight: 700;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: .08em;
    cursor: pointer;
    margin-left: 4px;
    white-space: nowrap;
}
.search-bar__select {
    flex: 1 1 120px;
    min-width: 80px;
    max-width: 100%;
    padding: 7px 10px;
    border: 1.5px solid var(--line);
    border-radius: 8px;
    background: var(--surface-strong);
    color: var(--text);
    font-family: "Inter",sans-serif;
    font-size: .85rem;
    transition: border-color .18s;
    box-sizing: border-box;
}
.search-bar__select:focus { outline: none; border-color: rgba(12,95,146,0.40); }

/* ============ RESULTS INFO ============ */
.results-info {
    max-width: var(--max-width);
    margin: 12px auto 0;
    padding: 0 16px;
    font-size: .80rem;
    font-family: "Space Grotesk",sans-serif;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .06em;
    color: var(--muted);
}

/* Papers anchor for scroll targeting */
.papers-anchor {
    display: block;
    height: 0;
    margin: 0;
    padding: 0;
}

/* ============ PAPER LIST ============ */
.papers {
    max-width: var(--max-width);
    margin: 14px auto 40px;
    padding: 0 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

/* Paper Card */
.paper-card {
    display: flex;
    flex-direction: column;
    border-radius: var(--radius-card);
    background: var(--surface-strong);
    border: 1px solid var(--line);
    box-shadow: 0 10px 22px rgba(8,59,99,0.05);
    overflow: hidden;
    transition: border-color .18s ease, box-shadow .18s ease;
}
.paper-card:hover {
    border-color: rgba(12,95,146,0.28);
    box-shadow: 0 14px 32px rgba(8,59,99,0.11);
}

.paper-card__header {
    padding: 16px 18px 10px;
}
.paper-card__topic-row {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 8px;
}
.paper-card__topic {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 999px;
    background: rgba(12,95,146,0.09);
    color: var(--brand-deep);
    font-family: "Space Grotesk",sans-serif;
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    margin-bottom: 8px;
}
.paper-card__id {
    display: inline-flex;
    align-items: center;
    padding: 3px 9px;
    border-radius: 8px;
    background: rgba(8,59,99,0.06);
    font-family: "Space Grotesk",sans-serif;
    font-size: .7rem;
    font-weight: 700;
    color: var(--brand-deep);
}
.paper-card__title {
    font-family: "Space Grotesk",sans-serif;
    font-size: 1.02rem;
    font-weight: 700;
    color: var(--text);
    line-height: 1.3;
    letter-spacing: -0.02em;
    margin-bottom: 6px;
}
.paper-card__authors {
    font-size: .88rem;
    color: var(--muted);
    line-height: 1.45;
    font-weight: 500;
}
.paper-card__affiliations-more {
    background: none;
    border: none;
    padding: 0;
    color: var(--brand);
    font-size: .78rem;
    cursor: pointer;
    font-family: "Inter",sans-serif;
    display: inline;
}
.affil-full .paper-card__affiliations-more {
    display: block;
    margin-top: 2px;
}
.paper-card__affiliations-more:hover { text-decoration: underline; }

/* Expandable abstract area */
.paper-card__body {
    max-height: 0;
    overflow: hidden;
    transition: max-height .35s ease, padding .35s ease;
    padding: 0 18px;
}
.paper-card.open .paper-card__body {
    max-height: 800px;
    padding: 0 18px 6px;
}
.paper-card__abstract-label {
    font-family: "Space Grotesk",sans-serif;
    font-size: .72rem;
    font-weight: 700;
    color: var(--brand);
    text-transform: uppercase;
    letter-spacing: .07em;
    margin-bottom: 5px;
}
.paper-card__abstract {
    font-size: .9rem;
    color: var(--muted);
    line-height: 1.7;
    margin-bottom: 12px;
}
mark {
    background: rgba(255, 213, 0, 0.40);
    color: inherit;
    border-radius: 2px;
    padding: 0 1px;
}
.paper-card__keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 12px;
}
.paper-card__keyword {
    background: rgba(12,95,146,0.07);
    color: var(--brand-deep);
    font-size: .72rem;
    font-family: "Space Grotesk",sans-serif;
    font-weight: 600;
    padding: 3px 9px;
    border-radius: 6px;
    border: 1px solid rgba(12,95,146,0.12);
}

.paper-card__actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    padding: 10px 18px 14px;
    border-top: 1px solid var(--line);
    margin-top: 2px;
}
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 18px;
    border-radius: 999px;
    font-family: "Space Grotesk",sans-serif;
    font-size: .82rem;
    font-weight: 700;
    letter-spacing: .04em;
    transition: background .18s, box-shadow .18s;
    border: none;
    text-decoration: none;
}
.btn:hover { text-decoration: none; }
.btn--primary {
    background: var(--brand);
    color: #fff;
    box-shadow: 0 2px 8px rgba(12,95,146,0.28);
}
.btn--primary:hover { background: var(--brand-deep); box-shadow: 0 4px 14px rgba(12,95,146,0.38); }
.btn--outline {
    background: transparent;
    color: var(--brand);
    border: 1.5px solid rgba(12,95,146,0.35);
}
.btn--outline:hover { background: rgba(12,95,146,0.07); border-color: var(--brand); }
.btn svg { width: 15px; height: 15px; }

/* Toggle indicator */
.paper-card__toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6px 16px 10px;
    font-family: "Space Grotesk",sans-serif;
    font-size: .74rem;
    font-weight: 700;
    color: var(--brand);
    letter-spacing: .04em;
    text-transform: uppercase;
    gap: 4px;
    cursor: pointer;
    user-select: none;
    transition: color .15s;
}
.paper-card__toggle:hover { color: var(--brand-deep); }
.paper-card__toggle svg {
    width: 16px;
    height: 16px;
    transition: transform .3s;
}
.paper-card.open .paper-card__toggle svg { transform: rotate(180deg); }

/* ============ PAGINATION ============ */
.pagination {
    max-width: var(--max-width);
    margin: 4px auto 28px;
    padding: 0 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 6px;
}
.pagination:empty { display: none; }
.pagination__btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 38px;
    height: 38px;
    padding: 0 10px;
    border: 1.5px solid var(--line);
    border-radius: 10px;
    background: var(--surface-strong);
    color: var(--text);
    font-family: "Space Grotesk",sans-serif;
    font-size: .84rem;
    font-weight: 700;
    cursor: pointer;
    transition: background .16s, border-color .16s, color .16s, box-shadow .16s;
    user-select: none;
}
.pagination__btn:hover:not(:disabled):not(.pagination__btn--active) {
    background: rgba(12,95,146,0.08);
    border-color: rgba(12,95,146,0.35);
    color: var(--brand);
}
.pagination__btn--active {
    background: var(--brand);
    border-color: var(--brand);
    color: #fff;
    font-weight: 700;
    pointer-events: none;
    box-shadow: 0 2px 10px rgba(12,95,146,0.30);
}
.pagination__btn:disabled { opacity: .38; cursor: default; }
.pagination__btn svg { width: 16px; height: 16px; }
.pagination__ellipsis {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 32px;
    height: 38px;
    color: var(--muted);
    font-size: .84rem;
    user-select: none;
}
.pagination__info {
    width: 100%;
    text-align: center;
    font-family: "Space Grotesk",sans-serif;
    font-size: .72rem;
    font-weight: 600;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: .06em;
    margin-top: 4px;
}

/* ============ EMPTY STATE ============ */
.empty-state {
    text-align: center;
    padding: 56px 16px;
    max-width: var(--max-width);
    margin: 0 auto;
}
.empty-state__icon { width: 52px; height: 52px; color: var(--muted); opacity: 0.3; margin: 0 auto 16px; }
.empty-state__text { color: var(--muted); margin-bottom: 18px; font-size: 1rem; }
.empty-state__btn {
    background: var(--brand);
    color: #fff;
    padding: 10px 24px;
    border-radius: 999px;
    font-family: "Space Grotesk",sans-serif;
    font-weight: 700;
    font-size: .84rem;
    letter-spacing: .04em;
    box-shadow: 0 2px 8px rgba(12,95,146,0.28);
    transition: background .18s;
}
.empty-state__btn:hover { background: var(--brand-deep); }

/* ============ ABOUT SECTION ============ */
.about {
    background:
        linear-gradient(180deg, rgba(255,255,255,0.96), rgba(245,239,226,0.92));
    border-top: 1px solid rgba(21,48,71,0.08);
    padding: 48px 16px;
    margin-top: 8px;
}
.about__container { max-width: var(--max-width); margin: 0 auto; }
.about__title {
    font-family: "Space Grotesk",sans-serif;
    font-size: clamp(1.4rem,3vw,2rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    color: var(--text);
    margin-bottom: 18px;
}
.about p { margin-bottom: 12px; color: var(--muted); font-size: .97rem; line-height: 1.7; }
.about__topics {
    margin: 22px 0;
    padding: 18px 20px;
    border-radius: var(--radius-card);
    background: rgba(12,95,146,0.04);
    border: 1px solid rgba(12,95,146,0.10);
}
.about__topics h3 {
    font-family: "Space Grotesk",sans-serif;
    font-size: .9rem;
    font-weight: 700;
    color: var(--brand);
    text-transform: uppercase;
    letter-spacing: .08em;
    margin-bottom: 12px;
}
.about__topics ul {
    list-style: none;
    display: grid;
    gap: 8px;
}
.about__topics li {
    position: relative;
    padding-left: 18px;
    font-size: .9rem;
    color: var(--muted);
    line-height: 1.5;
}
.about__topics li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--brand);
    font-weight: 700;
}
.about__link { margin-top: 16px; }
.about__link a { color: var(--brand); font-weight: 600; }
.about__link a:hover { color: var(--brand-deep); }

/* ============ SPONSORS SECTION ============ */
.sponsors {
    background: rgba(245,239,226,0.50);
    border-top: 1px solid rgba(21,48,71,0.08);
    padding: 40px 16px;
}
.sponsors__container { max-width: var(--max-width); margin: 0 auto; }
.sponsors__title {
    font-family: "Space Grotesk",sans-serif;
    font-size: clamp(1.2rem,3vw,1.7rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text);
    margin-bottom: 22px;
    text-align: center;
}
.sponsors__group-label {
    font-family: "Space Grotesk", sans-serif;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--muted, #6b7a8d);
    text-align: center;
    margin: 0 0 14px;
}
.sponsors__hosts {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 220px));
    gap: 14px;
    justify-content: center;
    margin-bottom: 28px;
}
.sponsors__hosts .sponsors__item {
    min-height: 110px;
    border-color: rgba(12,95,146,0.18);
    box-shadow: 0 2px 12px rgba(8,59,99,0.09);
}
.sponsors__hosts .sponsors__logo {
    max-height: 70px;
    filter: grayscale(0);
    opacity: 1;
}
.sponsors__divider {
    border: none;
    border-top: 1px solid rgba(21,48,71,0.10);
    margin: 0 0 24px;
}
.sponsors__grid {
    display: grid;
    grid-template-columns: repeat(2,1fr);
    gap: 12px;
}
.sponsors__item {
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,0.90);
    border: 1px solid rgba(21,48,71,0.08);
    border-radius: 18px;
    padding: 18px 16px;
    min-height: 96px;
    transition: box-shadow .18s, transform .18s, border-color .18s;
    text-decoration: none;
}
.sponsors__item:hover {
    box-shadow: 0 10px 28px rgba(8,59,99,0.12);
    transform: translateY(-2px);
    border-color: rgba(12,95,146,0.22);
    text-decoration: none;
}
.sponsors__logo {
    max-height: 54px;
    max-width: 100%;
    width: auto;
    object-fit: contain;
    filter: grayscale(20%);
    opacity: 0.88;
    transition: filter .18s, opacity .18s;
}
.sponsors__item:hover .sponsors__logo { filter: grayscale(0); opacity: 1; }

/* ============ FOOTER ============ */
.footer {
    background:
        linear-gradient(180deg, rgba(255,255,255,0.96), rgba(245,239,226,0.92));
    border-top: 1px solid rgba(21,48,71,0.08);
    padding: 32px 16px;
    font-size: .87rem;
}
.footer__container { max-width: var(--max-width); margin: 0 auto; }
.footer__brand { display: flex; align-items: center; gap: 10px; margin-bottom: 16px; }
.footer__logo { height: 32px; }
.footer__brand p {
    font-family: "Space Grotesk",sans-serif;
    font-weight: 700;
    font-size: .94rem;
    color: var(--text);
}
.footer__links { display: flex; flex-wrap: wrap; gap: 16px; margin-bottom: 14px; }
.footer__links a { color: var(--muted); font-size: .84rem; font-weight: 500; transition: color .15s; }
.footer__links a:hover { color: var(--brand); text-decoration: none; }
.footer__copy { color: var(--muted); font-size: .75rem; }
.footer__version { color: var(--muted); font-size: .65rem; opacity: .45; margin-top: .15rem; }

/* ============ BACK TO TOP ============ */
.back-to-top {
    position: fixed;
    bottom: 22px;
    right: 20px;
    width: 40px;
    height: 40px;
    background: var(--brand);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 24px rgba(8,59,99,0.28);
    transition: opacity .22s ease, transform .22s ease, background .18s;
    z-index: 80;
}
.back-to-top[hidden] { opacity: 0; pointer-events: none; transform: translateY(10px); }
.back-to-top:not([hidden]) { opacity: 1; transform: translateY(0); }
.back-to-top svg { width: 20px; height: 20px; }
.back-to-top:hover { background: var(--brand-deep); }

/* ============ MODAL ============ */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(21,48,71,0.52);
    z-index: 200;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding: 0;
    opacity: 0;
    transition: opacity .25s;
    pointer-events: none;
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
}
.modal-overlay:not([hidden]) { opacity: 1; pointer-events: auto; }
.modal {
    background: #f8fbfc;
    width: 100%;
    max-height: 90vh;
    border-radius: 28px 28px 0 0;
    overflow-y: auto;
    padding: 22px 18px 36px;
    transform: translateY(100%);
    transition: transform .32s cubic-bezier(0.4,0,0.2,1);
    position: relative;
}
.modal-overlay:not([hidden]) .modal { transform: translateY(0); }
.modal__close {
    position: sticky;
    top: 0;
    float: right;
    width: 34px;
    height: 34px;
    font-size: 1.1rem;
    color: var(--muted);
    background: var(--line);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1;
    transition: background .15s, color .15s;
}
.modal__close:hover { background: rgba(21,48,71,0.14); color: var(--text); }
.modal__content { clear: both; }
.modal__topic {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    border-radius: 999px;
    background: rgba(12,95,146,0.09);
    color: var(--brand-deep);
    font-family: "Space Grotesk",sans-serif;
    font-size: .7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .06em;
    margin-bottom: 10px;
}
.modal__title {
    font-family: "Space Grotesk",sans-serif;
    font-size: 1.18rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    line-height: 1.3;
    color: var(--text);
}
.modal__authors { font-size: .88rem; color: var(--muted); margin-bottom: 4px; }
.modal__id { font-size: .78rem; color: var(--muted); margin-bottom: 18px; }
.modal__section-label {
    font-family: "Space Grotesk",sans-serif;
    font-size: .72rem;
    font-weight: 700;
    color: var(--brand);
    text-transform: uppercase;
    letter-spacing: .07em;
    margin-bottom: 6px;
    margin-top: 18px;
}
.modal__abstract { font-size: .92rem; line-height: 1.72; color: var(--muted); }
.modal__keywords { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.modal__keyword {
    background: rgba(12,95,146,0.07);
    color: var(--brand-deep);
    font-size: .72rem;
    font-family: "Space Grotesk",sans-serif;
    font-weight: 600;
    padding: 3px 9px;
    border-radius: 6px;
    border: 1px solid rgba(12,95,146,0.12);
}
.modal__actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 22px; }

/* ============ LOADING SKELETON ============ */
.skeleton {
    background: linear-gradient(90deg, var(--line) 25%, rgba(238,245,247,0.8) 50%, var(--line) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: 8px;
}
@keyframes shimmer { to { background-position: -200% 0; } }
.skeleton--line { height: 14px; margin-bottom: 8px; }
.skeleton--line:nth-child(2) { width: 80%; }
.skeleton--line:nth-child(3) { width: 60%; }

/* ============ RESPONSIVE — TABLET & UP ============ */
@media (min-width: 600px) {
    .hero-card { margin: 22px 16px 24px; }
    .hero-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .search-bar { padding: 14px 24px; }
    .papers { padding: 0 24px; gap: 14px; }
    .about__topics ul { grid-template-columns: 1fr 1fr; }
    .sponsors__grid { grid-template-columns: repeat(3,1fr); }
    .modal {
        max-width: 640px;
        border-radius: 28px;
        margin: auto;
        max-height: 85vh;
    }
    .modal-overlay { align-items: center; padding: 24px; }
}

/* ============ RESPONSIVE — DESKTOP ============ */
@media (min-width: 900px) {
    :root { --header-height: 66px; }
    .header__container { padding: 12px 24px; }
    .header__logo { height: 44px; border-radius: 14px; }
    .header__title { font-size: 1.15rem; }
    .header__menu-btn { display: none; }
    .header__nav {
        display: flex !important;
        flex-direction: row;
        border: none;
        padding: 0 24px 8px;
        gap: 20px;
        background: transparent;
    }
    .header__nav-link {
        border: none;
        padding: 4px 0;
        font-size: .72rem;
    }
    .search-bar__input-wrap { flex: 1; }
    .sponsors__grid { grid-template-columns: repeat(3,1fr); gap: 16px; }
    .sponsors__logo { max-height: 66px; }
    .modal { max-width: 700px; padding: 28px 32px 36px; }
    .hero-card { margin: auto }
    .papers { margin-bottom: 48px; }
}

/* ============ PRINT ============ */
@media print {
    .header,.search-bar,.back-to-top,.modal-overlay,.paper-card__toggle { display: none; }
    .paper-card__body { max-height: none !important; padding: 0 18px 14px !important; }
    .hero-card { background: transparent; color: inherit; }
    body { background: #fff; }
}