/* Shuping Wu — personal academic site */
:root {
  --text: #1c1c1c;
  --muted: #666;
  --accent: #14655d;
  --rule: #e5e5e5;
  --bg: #ffffff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  color: var(--text);
  background: #fbfbfd; /* Apple's near-white */
}

/* Apple-style gradient: one smooth green wash rising from the bottom of the
   viewport, dissolving into near-white before it reaches the text. */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(140% 62% at 50% 118%,
      rgba(64, 145, 118, 0.34) 0%,     /* deep sea green */
      rgba(122, 191, 158, 0.24) 36%,   /* jade */
      rgba(190, 226, 205, 0.14) 58%,   /* pale mint */
      rgba(251, 251, 253, 0) 78%),
    linear-gradient(180deg, #ffffff 0%, #fbfbfd 100%);
}

/* ---------- Navigation ---------- */
nav {
  border-bottom: 1px solid var(--rule);
  background: rgba(255, 255, 255, 0.85);
}
.nav-inner {
  max-width: 760px;
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}
.nav-name {
  font-size: 20px;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.2px;
}
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  margin-left: 22px;
  font-size: 15.5px;
}
.nav-links a:hover { color: var(--accent); }
.nav-links a.active { color: var(--text); font-weight: 600; }

/* ---------- Layout ---------- */
main {
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}

h1 { font-size: 30px; font-weight: 700; margin: 0 0 6px; }
h2 {
  font-size: 21px;
  font-weight: 650;
  margin: 40px 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--rule);
}
a { color: var(--accent); }
a:hover { text-decoration: underline; }
.muted { color: var(--muted); }

/* ---------- Home ---------- */
.home-header {
  display: flex;
  gap: 36px;
  align-items: flex-start;
  flex-wrap: wrap;
  margin-bottom: 28px;
}
.headshot {
  width: 240px;
  height: 300px;
  object-fit: cover;
  object-position: center 22%;
  border-radius: 6px;
  flex-shrink: 0;
  background: #fff;
  border: 1px solid var(--rule);
}
.home-intro { flex: 1; min-width: 260px; }
.contact-line { margin: 10px 0 0; font-size: 16px; }
.contact-line a { margin-right: 6px; }

/* ---------- Research ---------- */
.paper { margin-bottom: 26px; }
.paper-title { font-weight: 650; }
.paper-authors { color: var(--muted); font-size: 15.5px; }
.paper-status { font-size: 15.5px; font-style: italic; }
.paper-desc { margin: 6px 0 0; font-size: 16px; }

/* ---------- CV embed ---------- */
.cv-frame {
  width: 100%;
  height: 82vh;
  min-height: 600px;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: #fff;
}
.cv-actions { margin: 14px 0 22px; }

/* ---------- Footer ---------- */
footer {
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 13.5px;
  text-align: center;
  padding: 20px 0 32px;
}

@media (max-width: 620px) {
  .home-header { flex-direction: column; align-items: center; text-align: center; }
  .nav-links a { margin-left: 14px; }
}