:root {
    --bg: #0d1117;
    --bg-soft: #161b22;
    --bg-card: #161b22;
    --border: #30363d;
    --text: #e6edf3;
    --text-dim: #8b949e;
    --accent: #58a6ff;
    --accent-2: #3fb950;
    --accent-soft: rgba(88, 166, 255, 0.12);
    --shadow: 0 1px 3px rgba(0,0,0,0.4);
    --radius: 12px;
}
:root[data-theme="light"] {
    --bg: #ffffff;
    --bg-soft: #f6f8fa;
    --bg-card: #ffffff;
    --border: #d0d7de;
    --text: #1f2328;
    --text-dim: #636c76;
    --accent: #0969da;
    --accent-2: #1a7f37;
    --accent-soft: rgba(9, 105, 218, 0.08);
    --shadow: 0 1px 3px rgba(27,31,36,0.12);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    line-height: 1.65;
    color: var(--text);
    background: var(--bg);
    margin: 0;
    -webkit-font-smoothing: antialiased;
    transition: background 0.3s ease, color 0.3s ease;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---- Nav ---- */
nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: color-mix(in srgb, var(--bg) 85%, transparent);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
}
.nav-inner {
    max-width: 980px;
    margin: 0 auto;
    padding: 12px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}
.nav-brand { font-weight: 700; font-size: 1.05em; letter-spacing: -0.01em; color: var(--text); }
.nav-brand:hover { text-decoration: none; }
.nav-brand .mono { color: var(--accent); }
.nav-links { display: flex; gap: 4px; flex-wrap: wrap; align-items: center; }
.nav-links a {
    color: var(--text-dim);
    font-size: 0.92em;
    padding: 6px 10px;
    border-radius: 6px;
    transition: color 0.2s, background 0.2s;
}
.nav-links a:hover { color: var(--text); background: var(--bg-soft); text-decoration: none; }
.nav-links a.active { color: var(--accent); background: var(--accent-soft); }
.theme-toggle {
    background: var(--bg-soft);
    border: 1px solid var(--border);
    color: var(--text);
    width: 36px; height: 36px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1em;
    display: inline-flex; align-items: center; justify-content: center;
    transition: background 0.2s, transform 0.2s;
}
.theme-toggle:hover { background: var(--accent-soft); transform: translateY(-1px); }

.wrap { max-width: 980px; margin: 0 auto; padding: 0 24px; }

/* ---- Hero (home) ---- */
header.hero {
    padding: 72px 24px 56px;
    border-bottom: 1px solid var(--border);
    background: radial-gradient(900px 400px at 80% -10%, var(--accent-soft), transparent 60%);
}
.hero-inner {
    max-width: 980px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 40px;
}
.hero-text { flex: 1 1 auto; min-width: 0; }
.hero-photo {
    flex: 0 0 auto;
    width: 200px;
    height: 200px;
    border-radius: var(--radius);
    object-fit: cover;
    object-position: center top;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
}
.eyebrow {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
    color: var(--accent-2);
    font-size: 0.85em;
    letter-spacing: 0.02em;
    margin-bottom: 14px;
}
h1 {
    font-size: clamp(2.2em, 5vw, 3.4em);
    line-height: 1.1;
    margin: 0 0 14px;
    letter-spacing: -0.02em;
}
.flags {
    display: flex;
    gap: 8px;
    font-size: 1.5em;
    line-height: 1;
    margin: 0 0 22px;
}
.tagline {
    font-size: clamp(1.05em, 2.4vw, 1.35em);
    color: var(--text-dim);
    max-width: 680px;
    margin: 0 0 28px;
}
.tagline strong { color: var(--text); font-weight: 600; }
.hero-links { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 9px 16px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text);
    font-size: 0.92em;
    font-weight: 500;
    transition: border-color 0.2s, transform 0.2s, background 0.2s;
}
.btn:hover { text-decoration: none; border-color: var(--accent); transform: translateY(-2px); }
.btn.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn.primary:hover { background: color-mix(in srgb, var(--accent) 88%, #000); }

/* ---- Page header (inner pages) ---- */
.page-head {
    padding: 56px 24px 36px;
    border-bottom: 1px solid var(--border);
    background: radial-gradient(900px 400px at 80% -10%, var(--accent-soft), transparent 60%);
}
.page-head .page-head-inner { max-width: 980px; margin: 0 auto; }
.page-head h1 { font-size: clamp(1.9em, 4vw, 2.6em); }
.page-head p { color: var(--text-dim); max-width: 700px; margin: 8px 0 0; font-size: 1.05em; }

/* ---- Sections ---- */
section { padding: 48px 0; border-bottom: 1px solid var(--border); }
section:last-of-type { border-bottom: none; }
.section-label {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
    color: var(--accent);
    font-size: 0.82em;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 6px;
}
h2 { font-size: 1.7em; margin: 0 0 28px; letter-spacing: -0.01em; }
h3 { font-size: 1.15em; margin: 0 0 4px; }
.lead { font-size: 1.08em; color: var(--text-dim); max-width: 760px; }
.lead strong { color: var(--text); }

/* ---- Timeline ---- */
.timeline { position: relative; }
.entry {
    position: relative;
    padding: 0 0 32px 28px;
    border-left: 2px solid var(--border);
}
.entry:last-child { padding-bottom: 0; }
.entry::before {
    content: "";
    position: absolute;
    left: -7px; top: 4px;
    width: 12px; height: 12px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 0 4px var(--bg);
}
.entry-head { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 4px 16px; align-items: baseline; }
.entry .org { color: var(--text-dim); font-size: 0.95em; }
.entry .when {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
    font-size: 0.82em;
    color: var(--text-dim);
    white-space: nowrap;
}
.entry .role { color: var(--accent-2); font-weight: 600; font-size: 0.95em; margin: 2px 0 8px; }
.proj-list { list-style: none; padding: 0; margin: 10px 0 0; }
.proj-list > li { margin-bottom: 12px; }
.proj-list .pname { font-weight: 600; }
.muted { color: var(--text-dim); }

/* ---- Cards / publications ---- */
.cards { display: grid; gap: 16px; }
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 22px;
    transition: border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}
.card:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: var(--shadow); }
.card .pub-title { font-weight: 600; font-size: 1.04em; margin: 0 0 8px; line-height: 1.4; }
.card .authors { color: var(--text-dim); font-size: 0.92em; margin: 0 0 10px; }
.card .authors .me { color: var(--text); font-weight: 700; }
.card-foot { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.tag {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
    font-size: 0.74em;
    padding: 3px 9px;
    border-radius: 20px;
    background: var(--accent-soft);
    color: var(--accent);
    border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
}
.tag.wip { background: rgba(210,153,34,0.12); color: #d29922; border-color: rgba(210,153,34,0.4); }
.tag.venue { background: var(--bg-soft); color: var(--text-dim); border-color: var(--border); }
.doi { font-size: 0.85em; }

/* ---- Software ---- */
.sw-list { display: flex; flex-direction: column; gap: 28px; }
.sw-item {
    display: flex;
    gap: 24px;
    align-items: flex-start;
    padding: 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}
.sw-item:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: var(--shadow); }
.sw-thumb {
    flex: 0 0 200px;
    width: 200px;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: calc(var(--radius) - 2px);
    overflow: hidden;
    line-height: 0;
}
.sw-thumb:hover { border-color: var(--accent); }
.sw-thumb img {
    display: block;
    width: 100%;
    height: 130px;
    object-fit: cover;
}
.sw-body { flex: 1 1 auto; min-width: 0; }
.sw-body h3 { font-size: 1.2em; margin-bottom: 6px; }
.sw-desc { margin: 0; font-size: 1.0em; }

@media (max-width: 560px) {
    .sw-item { flex-direction: column; gap: 16px; }
    .sw-thumb { flex-basis: auto; width: 100%; }
    .sw-thumb img { height: auto; }
}

/* ---- Skill groups ---- */
.skill-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.skill-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 20px; }
.skill-card h4 { margin: 0 0 12px; font-size: 0.95em; color: var(--accent); }
.chips { display: flex; flex-wrap: wrap; gap: 7px; }
.chip {
    font-size: 0.82em;
    padding: 4px 11px;
    border-radius: 6px;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    color: var(--text);
}

/* ---- Two-col grids ---- */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.award { padding: 14px 0; border-bottom: 1px solid var(--border); }
.award:last-child { border-bottom: none; }
.award .a-title { font-weight: 600; }

/* ---- Home highlights ---- */
.highlights { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 16px; margin-top: 8px; }
.stat { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 20px; }
.stat .num { font-size: 1.8em; font-weight: 700; color: var(--accent); line-height: 1; }
.stat .lbl { color: var(--text-dim); font-size: 0.9em; margin-top: 6px; }

footer {
    margin-top: auto;
    padding: 40px 24px 60px;
    text-align: center;
    color: var(--text-dim);
    font-size: 0.9em;
}
footer a { color: var(--text-dim); }
.footer-links { margin-bottom: 12px; display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }

@media (max-width: 680px) {
    .grid-2 { grid-template-columns: 1fr; gap: 0; }
    header.hero { padding: 48px 24px 40px; }
    .hero-inner { flex-direction: column-reverse; align-items: flex-start; gap: 24px; }
    .hero-photo { width: 140px; height: 140px; }
}