/* ============================================================
   Material / Google-style design system for leishu02.github.io
   ============================================================ */

:root {
    --g-blue:   #1a73e8;
    --g-blue-d: #1765cc;
    --g-red:    #ea4335;
    --g-yellow: #fbbc05;
    --g-green:  #34a853;

    --text:      #202124;  /* grey 900 */
    --text-2:    #5f6368;  /* grey 700 */
    --line:      #dadce0;  /* grey 300 */
    --bg:        #f8f9fa;  /* grey 50  */
    --surface:   #ffffff;

    --radius:    12px;
    --shadow-1:  0 1px 2px rgba(60,64,67,.30), 0 1px 3px 1px rgba(60,64,67,.15);
    --shadow-2:  0 1px 3px rgba(60,64,67,.30), 0 4px 8px 3px rgba(60,64,67,.15);
    --maxw:      960px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
    margin: 0;
    font-family: 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--g-blue); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Top app bar ---------- */
.appbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--surface);
    border-bottom: 1px solid var(--line);
}
.appbar-inner {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 24px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.brand {
    font-size: 20px;
    font-weight: 500;
    color: var(--text);
    letter-spacing: .2px;
    white-space: nowrap;
}
.brand:hover { text-decoration: none; }
.brand .dot-b { color: var(--g-blue); }
.brand .dot-r { color: var(--g-red); }
.brand .dot-y { color: var(--g-yellow); }
.brand .dot-g { color: var(--g-green); }

.nav {
    display: flex;
    gap: 4px;
    flex-wrap: wrap;
}
.nav a {
    color: var(--text-2);
    font-size: 14px;
    font-weight: 500;
    padding: 8px 14px;
    border-radius: 999px;
    transition: background .15s, color .15s;
}
.nav a:hover { background: #f1f3f4; color: var(--text); text-decoration: none; }
.nav a.active { color: var(--g-blue); background: #e8f0fe; }

/* ---------- Layout ---------- */
main { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
section { padding: 40px 0; }
.section-title {
    font-size: 24px;
    font-weight: 500;
    margin: 0 0 20px;
    color: var(--text);
}
.section-title .bar {
    display: inline-block;
    width: 36px; height: 4px;
    border-radius: 2px;
    background: var(--g-blue);
    vertical-align: middle;
    margin-right: 12px;
}

/* ---------- Hero ---------- */
.hero {
    position: relative;
    overflow: hidden;
    text-align: center;
    padding: 56px 24px 40px;
    background: url('../../images/bamboo-bg.webp') center/cover no-repeat;
    border-bottom: 1px solid #d0dbd2;
}
.hero > * {
    position: relative;
    z-index: 1;
}
.hero img.avatar {
    width: 152px; height: 152px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: var(--shadow-2);
    border: 4px solid #fff;
}
.hero h1 {
    font-size: 40px;
    font-weight: 500;
    margin: 20px 0 6px;
    letter-spacing: -.5px;
}
.hero .subtitle {
    color: var(--text-2);
    font-size: 16px;
    margin: 0 auto 22px;
    max-width: 640px;
}
.chips { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; margin-bottom: 24px; }
.chip {
    font-size: 13px; font-weight: 500;
    color: var(--text-2);
    background: #f1f3f4;
    padding: 6px 14px;
    border-radius: 999px;
}

/* social buttons */
.social { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.btn {
    display: inline-flex; align-items: center; gap: 8px;
    font-size: 14px; font-weight: 500;
    padding: 9px 18px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: var(--surface);
    color: var(--g-blue);
    transition: background .15s, box-shadow .15s;
}
.btn:hover { background: #f8faff; box-shadow: var(--shadow-1); text-decoration: none; }
.btn.solid { background: var(--g-blue); color: #fff; border-color: var(--g-blue); }
.btn.solid:hover { background: var(--g-blue-d); }

/* ---------- Cards ---------- */
.card {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 24px 28px;
    box-shadow: var(--shadow-1);
}
.card p:first-child { margin-top: 0; }
.card p:last-child { margin-bottom: 0; }

/* ---------- Lists (research focus, news) ---------- */
.rows { list-style: none; margin: 0; padding: 0; }
.rows > li {
    padding: 16px 0;
    border-bottom: 1px solid var(--line);
}
.rows > li:last-child { border-bottom: none; }
.rows .lead { font-weight: 500; color: var(--text); }
.rows .lead.b { color: var(--g-blue); }

/* ---------- Publications ---------- */
.pub-year {
    font-size: 14px;
    font-weight: 700;
    letter-spacing: .8px;
    text-transform: uppercase;
    color: var(--text-2);
    margin: 28px 0 8px;
    padding-bottom: 6px;
    border-bottom: 2px solid var(--line);
}
.pub-year:first-of-type { margin-top: 0; }
.pubs { list-style: none; margin: 0 0 4px; padding: 0; }
.pubs > li { padding: 14px 0; border-bottom: 1px solid #eef0f1; }
.pubs > li:last-child { border-bottom: none; }
.pubs .title { font-weight: 500; color: var(--text); }
.pubs .authors { color: var(--text-2); font-size: 14.5px; }
.pubs .venue { color: var(--text); font-style: italic; font-size: 14.5px; }
.pubs .me { font-weight: 700; color: var(--text); }
.pubs .links { margin-left: 6px; }
.pubs .links a { font-size: 13px; }
.tag-award { color: var(--g-red); font-weight: 500; font-size: 13.5px; }

/* ---------- Footer ---------- */
footer {
    border-top: 1px solid var(--line);
    background: var(--surface);
    margin-top: 24px;
}
.footer-inner {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 28px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
    color: var(--text-2);
    font-size: 14px;
}
.footer-inner .social .btn { padding: 7px 14px; }

/* ---------- Buttons row ---------- */
.actions { margin-top: 20px; }

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
    .appbar-inner { padding: 0 14px; height: 56px; }
    .nav a { padding: 7px 10px; }
    main { padding: 0 16px; }
    .hero { padding: 40px 16px 32px; }
    .hero h1 { font-size: 32px; }
    .card { padding: 20px; }
}