:root{
  --bg:#0b0d10;
  --panel:#12151b;
  --text:#e9eef5;
  --muted:#a8b3c2;
  --line:rgba(255,255,255,.10);
  --accent:#7aa7ff;
  --shadow: 0 12px 40px rgba(0,0,0,.35);
  --radius:16px;
}

:root[data-theme="light"]{
  --bg:#ffffff;
  --panel:#f5f7fb;
  --text:#0f172a;
  --muted:#475569;
  --line:rgba(15,23,42,.12);
  --accent:#2563eb;
  --shadow: 0 12px 40px rgba(2,6,23,.10);
}

*{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
  background:var(--bg);
  color:var(--text);
}

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

.container{
  width:min(1040px, calc(100% - 48px));
  margin:0 auto;
  padding: 28px 0 64px;
}

.top{
  position:sticky; top:0; z-index:50;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  border-bottom:1px solid var(--line);
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding: 14px 24px;
}

.brand{
  font-weight:800;
  letter-spacing:.4px;
  color:var(--text);
  text-decoration:none;
}

.nav{
  display:flex;
  gap:14px;
  align-items:center;
}
.nav a{
  color:var(--muted);
  font-weight:600;
  font-size:14px;
}
.nav a:hover{ color:var(--text); text-decoration:none; }

.theme{
  border:1px solid var(--line);
  background:var(--panel);
  color:var(--text);
  border-radius: 999px;
  width:40px; height:34px;
  cursor:pointer;
  box-shadow: var(--shadow);
}

.hero{
  display:grid;
  grid-template-columns: 1.3fr .7fr;
  gap:18px;
  margin-top: 18px;
}

@media (max-width: 900px){
  .hero{ grid-template-columns: 1fr; }
  .nav a{ display:none; }
}

h1{
  font-size:44px;
  margin: 6px 0 12px;
  line-height:1.05;
}
.lead{
  font-size: 16px;
  color: var(--muted);
  line-height:1.7;
  margin: 0 0 18px;
}

.cta{ display:flex; gap:10px; flex-wrap:wrap; margin: 12px 0 12px; }

.btn{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:10px 14px;
  border-radius: 999px;
  border:1px solid var(--line);
  background: var(--panel);
  color: var(--text);
  box-shadow: var(--shadow);
}
.btn:hover{ text-decoration:none; transform: translateY(-1px); }
.btn.primary{
  background: color-mix(in srgb, var(--accent) 28%, var(--panel));
  border-color: color-mix(in srgb, var(--accent) 60%, var(--line));
}

.meta{
  color: var(--muted);
  font-size: 13px;
  display:flex;
  gap:8px;
  flex-wrap:wrap;
  margin-top: 6px;
}

.section{ margin-top: 26px; }
h2{ font-size: 22px; margin: 0 0 12px; }

.card{
  border:1px solid var(--line);
  background: var(--panel);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
}

.grid2{
  display:grid;
  grid-template-columns: 1fr 1fr;
  gap:16px;
}
@media (max-width: 900px){ .grid2{ grid-template-columns: 1fr; } }

.list{ margin: 10px 0 0; padding-left: 18px; color: var(--muted); line-height:1.8; }
.muted{ color: var(--muted); }

.cards{
  display:grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
@media (max-width: 1000px){ .cards{ grid-template-columns: 1fr; } }

.cardHead{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:12px;
}
.tag{
  font-size: 12px;
  color: var(--muted);
  border:1px solid var(--line);
  padding: 4px 10px;
  border-radius: 999px;
}

.links{
  display:flex;
  gap:12px;
  flex-wrap:wrap;
  margin-top: 10px;
  font-size: 13px;
}

.pubs{ margin:0; padding-left:18px; }
.pubs li{ margin: 12px 0; }

.timeline{ display:flex; flex-direction:column; gap:12px; }
.titem{
  display:grid;
  grid-template-columns: 120px 1fr;
  gap: 14px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line);
}
.titem:last-child{ border-bottom:none; }
.when{ color: var(--muted); font-size: 13px; padding-top: 2px; }

.hint{
  color: var(--muted);
  font-size: 13px;
  margin-top: 10px;
}

.footer{
  margin-top: 30px;
  display:flex;
  justify-content:space-between;
  gap:10px;
  flex-wrap:wrap;
  color: var(--muted);
  font-size: 13px;
  border-top:1px solid var(--line);
  padding-top: 16px;
}
/* Flip card */
.flip-card{
  position: relative;
  width: 100%;
  height: 0;
  padding-bottom: 100%; /* 保证容器为方形 */
  perspective: 1200px;
  border-radius: var(--radius);
  outline: none;
}

.flip-inner{
  position: absolute;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 700ms cubic-bezier(.2,.8,.2,1);
  border-radius: var(--radius);
}

/* Flip card face */
.flip-face{
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius);
  overflow: hidden;
}

/* Hover / focus 翻转（桌面端） */
.flip-card:hover .flip-inner,
.flip-card:focus .flip-inner,
.flip-card:focus-visible .flip-inner{
  transform: rotateY(180deg);
}

/* 背面 */
.flip-back{
  transform: rotateY(180deg);
}

/* 你的图片样式（确保方形且不变形） */
.photo{
  display:block;
  width: 100%;
  height: 100%;
  object-fit: cover;  /* 保证图片铺满容器，同时保持比例 */
  border-radius: var(--radius);
}

/* 尊重“减少动画”系统设置 */
@media (prefers-reduced-motion: reduce){
  .flip-inner{ transition: none; }
}