*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}

:root{
  --accent:#818cf8;
  --accent-dark:#6366f1;
  --accent-light:#a5b4fc;
  --grad:linear-gradient(135deg,#818cf8,#c084fc);
  --bg:#0a0a12;
  --bg-alt:#0f0f1a;
  --bg-card:#161625;
  --bg-elevated:#1c1c2e;
  --text:#e8edf5;
  --text-sec:#8892a8;
  --text-muted:#5a6480;
  --border:#252538;
  --radius:10px;
  --radius-sm:6px;
  --transition:.25s ease;
  --mw:1040px;
  --hdr-h:56px
}

html{scroll-behavior:smooth;scroll-padding-top:var(--hdr-h)}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg);
  color:var(--text);
  line-height:1.6;
  -webkit-font-smoothing:antialiased
}
a{color:var(--accent);text-decoration:none;transition:color var(--transition)}
a:hover{color:var(--accent-light)}
img{max-width:100%;height:auto;display:block}
code{
  background:var(--bg-card);
  color:var(--accent-light);
  padding:2px 6px;
  border-radius:4px;
  font-size:.9em
}

.container{max-width:var(--mw);margin:0 auto;padding:0 20px}

.section{padding:64px 0}
.section-alt{background:var(--bg-alt)}
.section-title{
  font-size:clamp(1.3rem,2.5vw,1.75rem);
  font-weight:700;
  text-align:center;
  margin-bottom:4px
}
.section-title::after{
  content:'';
  display:block;
  width:36px;
  height:3px;
  border-radius:2px;
  margin:10px auto 0;
  background:var(--grad)
}
.section-desc{
  text-align:center;
  color:var(--text-sec);
  font-size:.95rem;
  margin-bottom:28px
}

.loading{text-align:center;color:var(--text-muted);padding:32px;font-size:.95rem}

/* header */
.site-header{
  position:fixed;top:0;left:0;right:0;z-index:100;
  height:var(--hdr-h);
  background:transparent;
  transition:background var(--transition)
}
.site-header.scrolled{background:rgba(10,10,18,.85);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px)}
.nav-container{display:flex;align-items:center;justify-content:space-between;height:100%}

.logo{
  font-size:1.2rem;font-weight:800;
  background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;
  letter-spacing:-.5px
}
.logo:hover{opacity:.85}

.main-nav{display:flex;gap:24px}
.main-nav a{
  color:var(--text-sec);font-size:.9rem;font-weight:500;padding:3px 0;
  position:relative
}
.main-nav a::after{
  content:'';position:absolute;bottom:-1px;left:0;
  width:0;height:2px;
  background:var(--grad);transition:width var(--transition);border-radius:1px
}
.main-nav a:hover::after,.main-nav a.active::after{width:100%}
.main-nav a:hover{color:var(--text)}

.menu-toggle{
  display:none;flex-direction:column;gap:5px;
  background:none;border:none;cursor:pointer;padding:4px
}
.menu-toggle span{display:block;width:22px;height:2px;background:var(--text);border-radius:2px;transition:var(--transition)}

/* hero */
.hero{
  position:relative;min-height:80vh;
  display:flex;align-items:center;justify-content:center;
  overflow:hidden
}
.hero::before{
  content:'';
  position:absolute;inset:0;z-index:0;
  background:radial-gradient(ellipse at 30% 50%,rgba(129,140,248,.08) 0%,transparent 60%),
             radial-gradient(ellipse at 70% 50%,rgba(192,132,252,.08) 0%,transparent 60%),
             radial-gradient(ellipse at 50% 0%,rgba(99,102,241,.04) 0%,transparent 50%)
}
.hero::after{
  content:'';
  position:absolute;inset:0;z-index:0;opacity:.015;
  background-image:radial-gradient(circle at 1px 1px,var(--text) 1px,transparent 0);
  background-size:32px 32px
}
.hero-content{position:relative;z-index:1;text-align:center;padding:80px 0 60px}
.hero-title{
  font-size:clamp(2.5rem,7vw,4.5rem);font-weight:800;letter-spacing:-2px;
  background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;
  line-height:1.1;margin-bottom:10px
}
.hero-subtitle{font-size:clamp(1rem,2vw,1.3rem);font-weight:600;color:var(--text);margin-bottom:6px}
.hero-desc{font-size:.95rem;color:var(--text-sec);margin-bottom:28px;max-width:440px;margin-left:auto;margin-right:auto}
.hero-actions{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}

.btn{
  display:inline-flex;align-items:center;
  padding:10px 24px;border-radius:var(--radius-sm);
  font-size:.9rem;font-weight:600;
  transition:all var(--transition);cursor:pointer;
  border:1.5px solid transparent
}
.btn-primary{
  background:var(--grad);color:#fff;
  box-shadow:0 3px 12px rgba(129,140,248,.3)
}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 5px 18px rgba(129,140,248,.4);color:#fff}
.btn-outline{background:transparent;border-color:var(--border);color:var(--text)}
.btn-outline:hover{border-color:var(--accent);color:var(--accent);transform:translateY(-1px)}

/* about */
.about-wrap{
  display:flex;gap:40px;align-items:center;
  max-width:760px;margin:0 auto
}
.about-text{flex:1}
.about-text p{color:var(--text-sec);font-size:.95rem;margin-bottom:12px;line-height:1.75}
.about-stats{display:flex;gap:16px;flex-shrink:0}
.stat-item{
  text-align:center;padding:18px 28px;
  background:var(--bg-card);border-radius:var(--radius);
  border:1px solid var(--border);
  min-width:100px
}
.stat-number{
  display:block;font-size:1.6rem;font-weight:800;
  background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text
}
.stat-label{display:block;font-size:.8rem;color:var(--text-muted);margin-top:2px}

/* announcements */
.announcements-list{display:flex;flex-direction:column;gap:16px;max-width:720px;margin:0 auto}
.announcement-card{
  background:var(--bg-card);border-radius:var(--radius);
  border:1px solid var(--border);overflow:hidden;
  transition:border-color var(--transition),background var(--transition)
}
.announcement-card:hover{border-color:var(--accent-dark);background:var(--bg-elevated)}
.announcement-card.has-image{display:grid;grid-template-columns:200px 1fr}
.announcement-image{width:100%;height:100%;object-fit:cover;min-height:140px;background:var(--bg-alt)}
.announcement-body{padding:20px}
.announcement-header{display:flex;align-items:baseline;gap:10px;margin-bottom:8px;flex-wrap:wrap}
.announcement-title{font-size:1rem;font-weight:700}
.announcement-date{font-size:.8rem;color:var(--text-muted);white-space:nowrap;margin-left:auto}
.announcement-content{color:var(--text-sec);font-size:.88rem;line-height:1.65}
.announcement-content p{margin-bottom:6px}
.announcement-content p:last-child{margin-bottom:0}

/* projects */
.projects-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(280px,1fr));
  gap:16px
}
.project-card{
  background:var(--bg-card);border-radius:var(--radius);
  border:1px solid var(--border);padding:20px;
  transition:border-color var(--transition),background var(--transition);
  display:flex;flex-direction:column
}
.project-card:hover{border-color:var(--accent-dark);background:var(--bg-elevated)}
.project-card-header{display:flex;align-items:flex-start;gap:14px;margin-bottom:12px}
.project-logo{
  width:40px;height:40px;border-radius:var(--radius-sm);
  background:var(--grad);
  display:flex;align-items:center;justify-content:center;flex-shrink:0;
  color:#fff;font-size:1.05rem;font-weight:700
}
.project-logo img{width:100%;height:100%;object-fit:cover;border-radius:var(--radius-sm)}
.project-name{font-size:1rem;font-weight:700;margin-bottom:2px}
.project-desc{color:var(--text-sec);font-size:.85rem;line-height:1.55;flex:1;margin-bottom:14px}
.project-link{
  display:inline-flex;align-items:center;gap:6px;
  font-size:.85rem;font-weight:600;color:var(--accent);align-self:flex-start
}
.project-link svg{width:14px;height:14px;transition:transform var(--transition)}
.project-link:hover svg{transform:translateX(3px)}

/* footer */
.site-footer{background:var(--bg-alt);border-top:1px solid var(--border);padding:28px 0 22px}
.footer-content{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}
.footer-brand{display:flex;align-items:center;gap:12px}
.footer-logo{font-size:1rem;font-weight:800;background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.footer-brand p{color:var(--text-muted);font-size:.85rem}
.footer-links{display:flex;gap:16px}
.footer-links a{color:var(--text-muted);font-size:.85rem}
.footer-links a:hover{color:var(--text)}
.footer-copy{color:var(--text-muted);font-size:.8rem;width:100%;text-align:center;margin-top:4px}

/* animations */
.fade-in{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease}
.fade-in.visible{opacity:1;transform:translateY(0)}

@media(max-width:768px){
  .section{padding:48px 0}
  .hero{min-height:auto}.hero-content{padding:72px 0 48px}
  .main-nav{
    position:fixed;top:var(--hdr-h);left:0;right:0;
    background:rgba(10,10,18,.96);backdrop-filter:blur(14px);
    flex-direction:column;padding:20px;gap:12px;
    transform:translateY(-110%);opacity:0;
    transition:all var(--transition);box-shadow:0 8px 24px rgba(0,0,0,.3)
  }
  .main-nav.open{transform:translateY(0);opacity:1}
  .main-nav a{font-size:1rem}
  .menu-toggle{display:flex}
  .about-wrap{flex-direction:column;gap:24px}
  .about-stats{width:100%;justify-content:center}
  .announcement-card.has-image{grid-template-columns:1fr}
  .announcement-image{height:160px}
  .projects-grid{grid-template-columns:1fr}
  .hero-title{letter-spacing:-1px}
  .footer-content{flex-direction:column;text-align:center}
}

@media(max-width:480px){
  .hero-actions{flex-direction:column;align-items:center}
  .btn{width:100%;max-width:200px;justify-content:center}
  .about-stats{flex-direction:column;align-items:center}
  .announcement-body{padding:16px}
  .stat-item{padding:14px 24px;min-width:80px}
}

@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important}
  .fade-in{opacity:1;transform:none}
}

/* skeleton */
@keyframes sk-shimmer{0%{background-position:-400px 0}100%{background-position:calc(400px + 100%) 0}}
.skeleton{
  background:linear-gradient(90deg,var(--bg-card) 28%,var(--bg-elevated) 40%,var(--bg-card) 52%);
  background-size:400px 100%;animation:sk-shimmer 1.8s ease-in-out infinite;
  border-radius:var(--radius);border:1px solid var(--border);padding:20px
}
.skeleton+.skeleton{margin-top:16px}
.sk-row{display:flex;align-items:center;gap:14px;margin-bottom:16px}
.sk-icon{width:40px;height:40px;border-radius:var(--radius-sm);background:rgba(255,255,255,.04);flex-shrink:0}
.sk-line{height:12px;border-radius:4px;background:rgba(255,255,255,.06);margin-bottom:10px}
.sk-line:last-child{margin-bottom:0}

/* back to top */
.back-to-top{
  position:fixed;bottom:28px;right:28px;left:auto;z-index:99;
  width:42px;height:42px;border-radius:50%;
  background:var(--bg-card);border:1px solid var(--border);
  color:var(--text-sec);cursor:pointer;
  display:flex;align-items:center;justify-content:center;
  opacity:0;transform:translateY(12px);pointer-events:none;
  transition:all var(--transition)
}
.back-to-top.visible{opacity:1;transform:translateY(0);pointer-events:auto}
.back-to-top:hover{border-color:var(--accent);color:var(--accent);background:var(--bg-elevated)}

@media(max-width:768px){.back-to-top{bottom:20px;right:20px;width:38px;height:38px}}