/* ============================================================
   Beijun Shen — academic website
   Design system: serif headings + clean sans body,
   restrained academic-blue accent, light/dark aware, print-friendly.
   ============================================================ */

:root {
    --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua",
             Georgia, "Times New Roman", serif;
    --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
            Arial, "Noto Sans", sans-serif;

    --bg: #ffffff;
    --surface: #f6f8fb;
    --text: #1b1f24;
    --muted: #5b6673;
    --heading: #14233b;
    --accent: #1a4d8f;
    --accent-soft: #eaf1fa;
    --border: #e4e8ee;

    --maxw: 900px;
    --radius: 8px;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #14171c;
        --surface: #1b1f26;
        --text: #e7e9ec;
        --muted: #9aa4b2;
        --heading: #eef1f5;
        --accent: #78add8;
        --accent-soft: #1e2836;
        --border: #2a303a;
    }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
    font-family: var(--sans);
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 22px 64px;
    line-height: 1.65;
    color: var(--text);
    background-color: var(--bg);
    font-size: 17px;
    -webkit-font-smoothing: antialiased;
}

/* ---------- Headings ---------- */
h1, h2, h3 {
    font-family: var(--serif);
    color: var(--heading);
    line-height: 1.2;
    font-weight: 700;
}

h1 {
    font-size: 2.15rem;
    margin: 0 0 0.15em;
    letter-spacing: -0.01em;
}

h2 {
    font-size: 1.5rem;
    margin: 0 0 0.6em;
    padding-bottom: 0.3em;
    border-bottom: 2px solid var(--border);
}

/* ---------- Links ---------- */
a {
    color: var(--accent);
    text-decoration: none;
}

a:hover { text-decoration: underline; }

/* ---------- Header / nav ---------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: color-mix(in srgb, var(--bg) 88%, transparent);
    backdrop-filter: saturate(180%) blur(8px);
    -webkit-backdrop-filter: saturate(180%) blur(8px);
    border-bottom: 1px solid var(--border);
    margin: 0 -22px 34px;
    padding: 0 22px;
}

.nav-inner {
    max-width: var(--maxw);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 6px 18px;
    padding: 13px 0;
}

.brand {
    font-family: var(--serif);
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--heading);
    letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; color: var(--accent); }

nav.menu {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
}

nav.menu a {
    color: var(--muted);
    font-weight: 500;
    font-size: 0.98rem;
    padding: 5px 11px;
    border-radius: 6px;
    transition: background-color 0.15s ease, color 0.15s ease;
}

nav.menu a:hover {
    text-decoration: none;
    color: var(--accent);
    background: var(--accent-soft);
}

nav.menu a.active {
    color: var(--accent);
    background: var(--accent-soft);
    font-weight: 600;
}

/* ---------- Profile / hero ---------- */
.container {
    display: flex;
    gap: 38px;
    align-items: flex-start;
    flex-wrap: wrap;
}

.profile-text {
    flex: 1;
    min-width: 300px;
}

.subtitle {
    font-size: 1.12rem;
    color: var(--muted);
    margin-top: 0.1em;
}

.profile-photo {
    width: 230px;
    max-width: 100%;
    height: auto;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: 0 6px 22px rgba(20, 35, 59, 0.10);
}

/* ---------- Icon / contact links ---------- */
.icon-links {
    margin-top: 20px;
    display: flex;
    flex-direction: column;
    gap: 9px;
}

.icon-link {
    display: inline-flex;
    align-items: center;
    gap: 11px;
    color: var(--text);
    width: fit-content;
    font-size: 0.98rem;
}

.icon-link:hover { color: var(--accent); text-decoration: none; }

.icon {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 26px;
    height: 26px;
    font-size: 13px;
    font-weight: 600;
    color: var(--accent);
    background: var(--accent-soft);
    border: 1px solid var(--border);
    border-radius: 50%;
    line-height: 1;
    flex-shrink: 0;
}

/* ---------- Sections ---------- */
.section { margin-top: 44px; }

ul { padding-left: 20px; }
li { margin-bottom: 9px; }

/* ---------- Research page project cards ---------- */
.project {
    margin-bottom: 0;
    padding: 18px 20px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent);
    border-radius: var(--radius);
}
.section.project { margin-top: 18px; }

.project-title {
    font-family: var(--serif);
    font-weight: 700;
    font-size: 1.12rem;
    color: var(--heading);
    margin-bottom: 4px;
}
.project p { margin: 0; }

/* ---------- Publications ---------- */
.pub-list { list-style: none; padding-left: 0; }

.pub-list li {
    margin-bottom: 16px;
    padding-left: 16px;
    border-left: 2px solid var(--border);
}

.pub-list a { color: var(--accent); }
.note { color: var(--muted); font-size: 0.92em; }

/* Author-role legend at the top of the Publications page — full-strength text
   (not muted), so "Corresponding author" / "Equal contribution" read clearly. */
.pub-legend {
    color: var(--text);
    font-size: 0.92em;
    margin-top: -0.2em;
}

/* Author-role markers (* corresponding, + equal contribution): bold, slightly larger,
   and high-contrast so they clearly draw attention, even inside the muted legend line.
   Uses --heading so it stays near-black in light mode and near-white in dark mode. */
sup {
    color: var(--heading);
    font-weight: 800;
    font-size: 0.9em;
    padding-left: 1px;
}

/* ---------- News ---------- */
.news-item {
    margin-bottom: 26px;
    padding-bottom: 26px;
    border-bottom: 1px solid var(--border);
}
.news-item:last-of-type { border-bottom: none; }
.news-item p { margin: 0; }

.news-photo {
    display: block;
    margin-top: 14px;
    max-width: 480px;
    width: 100%;
    height: auto;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

/* ---------- Footer ---------- */
.footer {
    margin-top: 56px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
    color: var(--muted);
    font-size: 0.88rem;
}

/* ---------- Responsive ---------- */
@media (max-width: 620px) {
    body { font-size: 16px; }
    h1 { font-size: 1.85rem; }
    h2 { font-size: 1.35rem; }
    .container { gap: 24px; }
    .profile-photo {
        width: 100%;
        max-width: 300px;
        order: -1;
        margin: 0 auto;
    }
    .brand { font-size: 1.05rem; }
}

/* ---------- Print ---------- */
@media print {
    .site-header { position: static; border: none; margin: 0 0 20px; }
    nav.menu { display: none; }
    body { color: #000; max-width: none; font-size: 12pt; }
    a { color: #000; text-decoration: underline; }
    .project, .pub-list li, .news-item { break-inside: avoid; }
}