/* =================================================================
   Mingfei Lu — Homepage
   Dark glassmorphism + aurora gradients + scholar layout
   ================================================================= */

:root {
  /* light theme (default) — soft, premium, cards-on-paper */
  --bg: #f6f7fb;
  --bg-2: #ffffff;
  --surface: rgba(255, 255, 255, 0.72);
  --surface-2: rgba(255, 255, 255, 0.94);
  --border: rgba(15, 20, 40, 0.08);
  --border-2: rgba(15, 20, 40, 0.16);
  --text: #15182a;
  --text-dim: #4a5066;
  --text-muted: #8088a0;
  --accent: #4a5cff;     /* indigo */
  --accent-2: #8b5cff;   /* violet */
  --accent-3: #00a6d6;   /* cyan */
  --accent-warm: #ff8c5a;
  --shadow-lg: 0 24px 48px -20px rgba(40, 50, 100, 0.18),
               0 8px 18px -10px rgba(40, 50, 100, 0.10);
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --font-display: "Playfair Display", Georgia, serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
}

html[data-theme="dark"] {
  --bg: #0a0c12;
  --bg-2: #0e1119;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-2: rgba(255, 255, 255, 0.06);
  --border: rgba(255, 255, 255, 0.09);
  --border-2: rgba(255, 255, 255, 0.14);
  --text: #e7eaf2;
  --text-dim: #a8b0c2;
  --text-muted: #6f778a;
  --accent: #7c8cff;
  --accent-2: #b389ff;
  --accent-3: #5cd1ff;
  --accent-warm: #ffb47a;
  --shadow-lg: 0 30px 60px -25px rgba(0, 0, 0, 0.6),
               0 12px 24px -12px rgba(0, 0, 0, 0.4);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  background-image:
    radial-gradient(1200px 800px at 80% -10%, rgba(124, 140, 255, 0.10), transparent 60%),
    radial-gradient(900px 700px at -10% 30%, rgba(179, 137, 255, 0.08), transparent 60%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; transition: color .15s ease; }
a:hover { color: var(--accent-2); }

.ilink { border-bottom: 1px solid rgba(124, 140, 255, 0.4); }
.ilink:hover { border-bottom-color: var(--accent-2); }

.muted { color: var(--text-dim); }
.small { font-size: 0.9rem; }

/* ============== AURORA BG ============== */
.bg-aurora {
  position: fixed; inset: 0; z-index: -1; overflow: hidden;
  pointer-events: none;
}
.orb {
  position: absolute; border-radius: 50%; filter: blur(80px);
  opacity: 0.32;
  animation: float 18s ease-in-out infinite;
}
html[data-theme="dark"] .orb { opacity: 0.55; }
.orb-1 { width: 480px; height: 480px; top: -120px; left: -120px;
  background: radial-gradient(circle, #6a7bff 0%, transparent 70%); }
.orb-2 { width: 540px; height: 540px; top: 30%; right: -160px;
  background: radial-gradient(circle, #b389ff 0%, transparent 70%); animation-delay: -6s; }
.orb-3 { width: 420px; height: 420px; bottom: -120px; left: 30%;
  background: radial-gradient(circle, #5cd1ff 0%, transparent 70%); animation-delay: -12s; }
@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(40px, -30px) scale(1.08); }
}
.grid-overlay {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(15,20,40,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(15,20,40,0.04) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 30%, #000 30%, transparent 90%);
}
html[data-theme="dark"] .grid-overlay {
  background-image:
    linear-gradient(rgba(255,255,255,0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.025) 1px, transparent 1px);
}

/* ============== TOP NAV ============== */
.topnav {
  position: sticky; top: 0; z-index: 100;
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  background: linear-gradient(to bottom, rgba(255,255,255,0.85), rgba(255,255,255,0.55));
  border-bottom: 1px solid var(--border);
}
html[data-theme="dark"] .topnav {
  background: linear-gradient(to bottom, rgba(10,12,18,0.75), rgba(10,12,18,0.4));
}
.topnav__inner {
  max-width: 1280px; margin: 0 auto; padding: 14px 32px;
  display: flex; align-items: center; gap: 24px;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 1.05rem; color: var(--text);
  letter-spacing: -0.01em;
}
.brand:hover { color: var(--text); }
.brand-dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 12px var(--accent);
}
.topnav__links {
  display: flex; gap: 4px; margin-left: auto;
}
.topnav__links a {
  color: var(--text-dim); font-size: 0.92rem; font-weight: 500;
  padding: 8px 14px; border-radius: 8px;
}
.topnav__links a:hover {
  color: var(--text); background: var(--surface);
}
.theme-toggle {
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text-dim); width: 38px; height: 38px; border-radius: 10px;
  cursor: pointer; transition: all .2s; display: inline-flex; align-items: center; justify-content: center;
}
.theme-toggle:hover { color: var(--text); border-color: var(--border-2); }

/* ============== LAYOUT ============== */
.layout {
  max-width: 1280px;
  margin: 0 auto;
  padding: 48px 32px 80px;
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 56px;
  align-items: flex-start;
}

/* ============== SIDEBAR ============== */
.sidebar { position: relative; }
.sidebar__sticky {
  position: sticky; top: 96px;
  background: var(--surface);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  box-shadow: var(--shadow-lg);
}

.portrait-wrap {
  position: relative; width: 55%;
  margin: 0 auto 20px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: 0 12px 40px rgba(124, 140, 255, 0.18), 0 2px 8px rgba(0,0,0,0.18);
  border: 1px solid var(--border);
  background: var(--bg-2);
}
.portrait {
  width: 100%; height: auto;
  display: block;
  position: relative; z-index: 2;
  transition: transform .6s cubic-bezier(.2,.8,.2,1);
}
.portrait-wrap:hover .portrait { transform: scale(1.03); }
.portrait-glow { display: none; }
@keyframes spin { to { transform: rotate(360deg); } }

.name {
  font-size: 1.5rem; font-weight: 700;
  margin: 0 0 4px; text-align: center;
  letter-spacing: -0.02em;
}
.name-cn {
  font-size: 0.85rem; font-weight: 400;
  color: var(--text-dim); margin-left: 6px;
}
.tagline {
  font-size: 0.85rem; color: var(--text-dim);
  text-align: center; margin: 0 0 20px;
  line-height: 1.5;
}

.meta {
  list-style: none; padding: 0; margin: 0 0 18px;
  font-size: 0.85rem; color: var(--text-dim);
}
.meta li {
  display: flex; align-items: center; gap: 10px;
  padding: 6px 0;
}
.meta li i {
  width: 16px; color: var(--accent); font-size: 0.85rem;
}

.social {
  list-style: none; padding: 0; margin: 0 0 20px;
  display: flex; gap: 8px; justify-content: center; flex-wrap: wrap;
}
.social a {
  width: 38px; height: 38px; border-radius: 10px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  display: inline-flex; align-items: center; justify-content: center;
  color: var(--text-dim); font-size: 0.95rem;
  transition: all .2s;
}
.social a:hover {
  color: #fff; transform: translateY(-2px);
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-color: transparent;
  box-shadow: 0 8px 20px rgba(124, 140, 255, 0.35);
}

.cta {
  display: flex; flex-direction: column; gap: 8px;
  margin-bottom: 18px;
}
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 14px; border-radius: 10px;
  font-size: 0.88rem; font-weight: 600;
  transition: all .2s; cursor: pointer;
  border: 1px solid transparent;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  box-shadow: 0 8px 20px rgba(124, 140, 255, 0.3);
}
.btn-primary:hover { transform: translateY(-1px); color: #fff; box-shadow: 0 10px 24px rgba(124, 140, 255, 0.45); }
.btn-ghost {
  background: var(--surface-2); border-color: var(--border);
  color: var(--text);
}
.btn-ghost:hover { color: var(--text); border-color: var(--border-2); }

.status-card {
  padding: 12px 14px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(92, 209, 255, 0.08), rgba(124, 140, 255, 0.08));
  border: 1px solid rgba(92, 209, 255, 0.2);
  font-size: 0.8rem;
}
.status-row {
  display: flex; align-items: center; gap: 8px;
  font-weight: 600; color: var(--text);
}
.status-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: #5be88c;
  box-shadow: 0 0 0 3px rgba(91, 232, 140, 0.2);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 3px rgba(91, 232, 140, 0.2); }
  50% { box-shadow: 0 0 0 6px rgba(91, 232, 140, 0); }
}
.status-sub { color: var(--text-dim); margin-top: 2px; line-height: 1.4; }

/* ============== CONTENT ============== */
.content { min-width: 0; }

.section { margin-bottom: 72px; scroll-margin-top: 90px; }
.section-eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.74rem; font-weight: 500;
  color: var(--accent);
  text-transform: uppercase; letter-spacing: 0.12em;
  margin-bottom: 12px;
}
.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.5vw, 2.4rem);
  font-weight: 700;
  margin: 0 0 24px;
  line-height: 1.2;
  letter-spacing: -0.02em;
}
.grad {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-2) 60%, var(--accent-3) 100%);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}

.lead {
  font-size: 1.08rem; color: var(--text); line-height: 1.75;
  margin-top: 0;
}

/* About: stat cards */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin: 28px 0 8px;
}
.stat {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: center;
  gap: 4px;
  padding: 16px 18px;
  border-radius: 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  transition: all .25s ease;
  text-decoration: none;
}
.stat:hover {
  transform: translateY(-2px);
  border-color: var(--border-2);
  box-shadow: var(--shadow-md);
}
.stat__num {
  font-size: 1.65rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-2) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1.1;
}
.stat__label {
  font-size: 0.78rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
@media (max-width: 720px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
}

/* About chips */
.chips {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin-top: 24px;
}
.chip {
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  font-size: 0.82rem; color: var(--text-dim);
  transition: all .2s;
}
.chip:hover {
  color: var(--text); border-color: var(--border-2); transform: translateY(-1px);
}

/* News timeline */
.news { list-style: none; padding: 0; margin: 0; }
.news__item {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 20px;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  transition: all .2s;
  margin-bottom: 6px;
}
.news__item:hover {
  background: var(--surface);
  border-color: var(--border);
}
.news__date {
  font-family: var(--font-mono);
  font-size: 0.82rem; font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
}
.news__body { color: var(--text); line-height: 1.65; }
.news__item--muted .news__date,
.news__item--muted .news__body { color: var(--text-muted); }

/* Paper card */
.paper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px 26px;
  margin-bottom: 18px;
  transition: all .25s;
  position: relative;
  overflow: hidden;
}
.paper::before {
  content: ""; position: absolute; left: 0; top: 0; bottom: 0;
  width: 3px;
  background: linear-gradient(180deg, var(--accent), var(--accent-2));
  opacity: 0; transition: opacity .25s;
}
.paper:hover {
  border-color: var(--border-2);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}
.paper:hover::before { opacity: 1; }

.paper__badge { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 12px; }
.badge {
  font-family: var(--font-mono);
  font-size: 0.7rem; font-weight: 600;
  padding: 3px 10px; border-radius: 6px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.badge--accent {
  color: #fff;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-color: transparent;
}

.paper__title {
  font-size: 1.15rem; font-weight: 700;
  margin: 0 0 8px; line-height: 1.4;
  letter-spacing: -0.01em;
}
.paper__title a { color: var(--text); }
.paper__title a:hover { color: var(--accent-2); }

.paper__authors {
  font-size: 0.9rem; color: var(--text-dim);
  margin: 0 0 4px;
}
.paper__authors strong { color: var(--text); font-weight: 700; }
.paper__venue { font-size: 0.85rem; color: var(--text-muted); margin: 0 0 12px; }
.paper__abstract {
  font-size: 0.92rem; color: var(--text-dim); line-height: 1.65;
  margin: 0 0 14px;
}
.paper__links { display: flex; gap: 6px; flex-wrap: wrap; }
.paper__links a {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 12px; border-radius: 8px;
  font-size: 0.82rem; font-weight: 500;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
}
.paper__links a:hover {
  color: var(--text); border-color: var(--accent);
}

/* Projects grid */
.projects {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}
.project {
  display: block;
  padding: 22px 22px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  color: var(--text);
  transition: all .25s;
  position: relative; overflow: hidden;
}
.project::after {
  content: "↗"; position: absolute; top: 16px; right: 18px;
  color: var(--text-muted); font-size: 1.1rem;
  transition: all .2s;
}
.project:hover {
  color: var(--text); transform: translateY(-3px);
  border-color: var(--border-2);
  box-shadow: var(--shadow-lg);
}
.project:hover::after { color: var(--accent); transform: translate(2px, -2px); }
.project__icon { font-size: 1.6rem; margin-bottom: 8px; }
.project h3 {
  font-size: 1.05rem; font-weight: 700;
  margin: 0 0 6px; letter-spacing: -0.01em;
}
.project p {
  font-size: 0.88rem; color: var(--text-dim);
  line-height: 1.55; margin: 0 0 12px;
}
.project__tags { display: flex; gap: 6px; flex-wrap: wrap; }
.project__tags span {
  font-family: var(--font-mono);
  font-size: 0.7rem; font-weight: 500;
  padding: 2px 8px; border-radius: 5px;
  background: var(--surface-2);
  color: var(--text-muted);
}

/* Education timeline */
.timeline { list-style: none; padding: 0; margin: 0; }
.timeline li {
  display: grid; grid-template-columns: 160px 1fr; gap: 20px;
  padding: 16px 0; border-bottom: 1px dashed var(--border);
}
.timeline li:last-child { border-bottom: none; }
.timeline__when {
  font-family: var(--font-mono); font-size: 0.85rem; font-weight: 600;
  color: var(--accent);
}
.timeline__what { color: var(--text); line-height: 1.6; }

/* Footer */
.footer {
  margin-top: 80px; padding-top: 32px;
  border-top: 1px solid var(--border);
}
.footer__row {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; flex-wrap: wrap;
  font-size: 0.85rem; color: var(--text-muted);
}
.footer__links { display: flex; gap: 10px; }

/* ============== RESPONSIVE ============== */
@media (max-width: 980px) {
  .layout { grid-template-columns: 1fr; gap: 32px; padding: 32px 20px 60px; }
  .sidebar__sticky { position: static; }
  .topnav__inner { padding: 12px 20px; }
  .topnav__links { display: none; }
}
@media (max-width: 600px) {
  .news__item, .timeline li { grid-template-columns: 1fr; gap: 4px; }
  .news__date { font-size: 0.78rem; }
  .section { margin-bottom: 56px; }
  .paper { padding: 20px; }
}

/* prefers-reduced-motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}

/* ===== Visitor globe ===== */
.visitor-globe {
  margin-top: 18px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  text-align: center;
}
.visitor-globe .globe-canvas {
  width: 100%;
  max-width: 230px;
  margin: 0 auto;
  aspect-ratio: 1 / 1;
  min-height: 180px;
}
.visitor-globe .globe-canvas canvas { display: block; }
.visitor-globe .globe-label {
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  letter-spacing: 0.2px;
}
.visitor-globe .globe-label i { color: var(--accent); margin-right: 2px; }