/* GoAhead Academic Site — Blue-tone stylesheet */
:root {
  --bg: #f4f6f9;
  --paper: rgba(255,255,255,.92);
  --paper-strong: rgba(255,255,255,.98);
  --ink: #1a2a3a;
  --ink-soft: #5a6a7a;
  --line: rgba(26,42,58,.10);
  --accent: #2a5d84;
  --accent-deep: #1b3f5e;
  --accent-soft: rgba(42,93,132,.10);
  --accent-light: #e8f0f7;
  --steel: #607789;
  --steel-soft: rgba(96,119,137,.10);
  --shadow: 0 8px 32px rgba(20,35,50,.08);
  --shadow-lg: 0 16px 48px rgba(20,35,50,.12);
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --container: min(1140px, calc(100vw - 40px));
  --header-h: 64px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;color:var(--ink);background:var(--bg);font-family:"Noto Sans SC","Source Han Sans SC","PingFang SC",system-ui,sans-serif;line-height:1.7;font-size:15px}
img,video{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
p{margin:0 0 .8rem}
h1,h2,h3,h4{margin:0;font-family:"Noto Serif SC","Source Han Serif SC",serif;line-height:1.25}

/* ---- Layout Shell ---- */
.site-shell{position:relative;z-index:1}
.wrap{width:var(--container);margin:0 auto}

/* ---- Header ---- */
.site-header{position:sticky;top:0;z-index:50;backdrop-filter:blur(14px);background:rgba(244,246,249,.88);border-bottom:1px solid var(--line);height:var(--header-h)}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;height:100%}
.brand{display:flex;align-items:baseline;gap:10px}
.brand-mark{font-family:"Noto Serif SC",serif;font-size:1.35rem;font-weight:700;color:var(--accent-deep)}
.brand-sub{color:var(--ink-soft);font-size:.82rem;display:none}
@media(min-width:900px){.brand-sub{display:inline}}

.site-nav{display:flex;gap:4px}
.site-nav a{padding:8px 14px;border-radius:999px;color:var(--ink-soft);font-size:.9rem;transition:background .18s,color .18s}
.site-nav a:hover,.site-nav a.is-active{color:var(--accent-deep);background:var(--accent-soft)}

/* Hamburger */
.nav-toggle{display:none;background:none;border:none;padding:8px;cursor:pointer}
.nav-toggle span{display:block;width:22px;height:2px;background:var(--ink);margin:5px 0;border-radius:2px;transition:transform .2s}
@media(max-width:768px){
  .nav-toggle{display:block}
  .site-nav{display:none;position:absolute;top:var(--header-h);left:0;right:0;background:var(--paper-strong);flex-direction:column;padding:12px 20px;border-bottom:1px solid var(--line);box-shadow:var(--shadow)}
  .site-nav.is-open{display:flex}
  .site-nav a{padding:12px 0;font-size:1rem}
}

/* ---- Section ---- */
.section{padding:48px 0}
.section + .section{border-top:1px solid var(--line)}
.section-head{max-width:720px;margin-bottom:28px}
.section-head h2{font-size:clamp(1.5rem,2.4vw,2.2rem);margin-bottom:8px}
.section-head p{color:var(--ink-soft)}

.kicker{display:inline-flex;align-items:center;gap:6px;color:var(--accent);font-size:.78rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;margin-bottom:8px}
.kicker::before{content:"";width:8px;height:8px;border-radius:50%;background:var(--accent)}

/* ---- Hero ---- */
.hero-section{padding-top:18px}

/* Banner — full-width screenshot */
.hero-banner{border-radius:16px;overflow:hidden;box-shadow:0 12px 32px rgba(20,35,50,.10);background:#dfe8f0}
.hero-banner img{width:100%;display:block;aspect-ratio:2.8/1;object-fit:cover;object-position:left top}

/* Bottom row — text + monitor side by side */
.hero-bottom{display:grid;grid-template-columns:1fr 1fr;gap:36px;align-items:center;margin-top:32px}
.hero-copy{padding:4px 0}
.hero-copy h1{font-size:clamp(2.2rem,3.6vw,3.4rem);line-height:1.06;letter-spacing:-.02em;margin:0 0 10px}
.hero-summary{margin:0 0 12px;color:var(--accent-deep);font-size:1rem;font-weight:700;letter-spacing:.02em}
.hero-copy .lede{margin:0;color:var(--ink-soft);font-size:.95rem;line-height:1.85}
.hero-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}

/* Monitor mockup — thin bezel style */
.hero-device{display:flex;flex-direction:column;align-items:center}
.monitor{width:100%;border-radius:6px;overflow:hidden;box-shadow:0 8px 30px rgba(20,35,50,.16)}
.monitor-screen{background:#111;padding:3px 3px 0;border-radius:6px 6px 0 0}
.monitor-screen video{width:100%;display:block;aspect-ratio:16/9;object-fit:cover;background:#0b1116;border-radius:3px 3px 0 0}
.monitor-chin{height:16px;background:#111;border-radius:0 0 6px 6px;position:relative}
.monitor-chin::after{content:"";position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:8px;height:8px;border-radius:50%;background:#222}
.monitor-neck{width:24px;height:18px;background:#333;border-radius:0 0 2px 2px}
.monitor-base{width:72px;height:6px;background:#333;border-radius:3px;margin-top:-1px}

@media(max-width:980px){.hero-bottom{grid-template-columns:1fr;gap:24px}.hero-banner img{aspect-ratio:2.2/1}}
@media(max-width:640px){.hero-copy h1{font-size:2rem}.hero-summary{font-size:.93rem}.hero-copy .lede{font-size:.9rem;line-height:1.8}.hero-actions{margin-top:14px}}

/* ---- Buttons ---- */
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:42px;padding:0 20px;border-radius:999px;font-weight:600;font-size:.9rem;transition:transform .15s,box-shadow .15s}
.btn:hover{transform:translateY(-1px);box-shadow:0 8px 20px rgba(20,35,50,.14)}
.btn-primary{background:var(--accent);color:#fff}
.btn-outline{background:var(--paper);border:1px solid var(--line);color:var(--ink)}

/* ---- Cards ---- */
.card{background:var(--paper);border:1px solid rgba(255,255,255,.8);border-radius:var(--radius-lg);box-shadow:var(--shadow);padding:24px}
.card h3{margin-bottom:8px;font-size:1.05rem}
.card p,.card li{color:var(--ink-soft);font-size:.92rem}

/* ---- Grid Layouts ---- */
.grid-2{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.grid-4{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.grid-6{display:grid;grid-template-columns:repeat(6,1fr);gap:12px}
@media(max-width:1000px){.grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}.grid-6{grid-template-columns:repeat(3,1fr)}}
@media(max-width:640px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}.grid-6{grid-template-columns:repeat(2,1fr)}}

/* ---- Feature Cards ---- */
.feature-card{text-align:center;padding:28px 20px}
.feature-icon{display:inline-flex;align-items:center;justify-content:center;width:56px;height:56px;border-radius:14px;background:var(--accent-soft);color:var(--accent);margin-bottom:12px}

/* ---- Media Surface ---- */
.media-box{border-radius:var(--radius-md);overflow:hidden;background:#0c1418;border:1px solid var(--line)}
.media-box video,.media-box img{width:100%;display:block;object-fit:cover}
.media-box.aspect-16-9 video,.media-box.aspect-16-9 img{aspect-ratio:16/9}

/* ---- Split Section (text + media) ---- */
.split{display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:center}
.split.reverse{direction:rtl}
.split.reverse > *{direction:ltr}
@media(max-width:900px){.split,.split.reverse{grid-template-columns:1fr;direction:ltr}}

/* ---- Timeline ---- */
.timeline{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.timeline-item{position:relative;padding:20px;padding-top:28px;background:var(--paper);border-radius:var(--radius-md);box-shadow:var(--shadow)}
.timeline-item::before{content:"";position:absolute;top:0;left:20px;right:20px;height:3px;background:linear-gradient(90deg,var(--accent),var(--accent-soft));border-radius:2px}
.timeline-period{display:block;color:var(--accent);font-weight:700;font-size:.85rem;margin-bottom:4px}
.timeline-item h3{font-size:.95rem;margin-bottom:4px}
.timeline-item p{color:var(--ink-soft);font-size:.85rem;margin:0}
/* Timeline with images */
.timeline-rich .timeline-item{padding-top:0;overflow:hidden}
.timeline-rich .timeline-item::before{display:none}
.timeline-media{margin:-20px -20px 12px;border-radius:0}
.timeline-media img{width:100%;height:100%;object-fit:cover}
@media(max-width:900px){.timeline{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){.timeline{grid-template-columns:1fr}}

/* ---- KPI Strip ---- */
.kpi-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.kpi-card{background:var(--paper);border-radius:var(--radius-md);padding:20px;box-shadow:var(--shadow)}
.kpi-value{color:var(--accent);font-size:1.8rem;font-weight:800;line-height:1;margin-bottom:6px}
.kpi-card p{color:var(--ink-soft);font-size:.88rem;margin:0}
@media(max-width:900px){.kpi-strip{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){.kpi-strip{grid-template-columns:1fr}}

/* ---- Step Cards ---- */
.step-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.step-card{padding:20px}
.step-num{display:inline-flex;align-items:center;justify-content:center;width:32px;height:32px;border-radius:50%;background:var(--accent);color:#fff;font-weight:700;font-size:.85rem;margin-bottom:12px}
.step-card .media-box{margin-top:14px}
@media(max-width:900px){.step-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){.step-grid{grid-template-columns:1fr}}

/* ---- Capability Cards (with media) ---- */
.cap-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
.cap-card{padding:16px}
.cap-card .media-box{margin-bottom:12px}
.cap-card h3{font-size:1rem;margin-bottom:6px}
.cap-card p{font-size:.88rem}
@media(max-width:640px){.cap-grid{grid-template-columns:1fr}}

/* ---- Video Grid (3 col) ---- */
.vid-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.vid-item{border-radius:var(--radius-md);overflow:hidden;background:#0c1418;box-shadow:var(--shadow)}
.vid-item video{width:100%;aspect-ratio:16/9;object-fit:cover;display:block}
.vid-item .vid-label{padding:10px 14px;background:var(--paper);font-size:.88rem;font-weight:600}
@media(max-width:900px){.vid-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:640px){.vid-grid{grid-template-columns:1fr}}

/* ---- IP Gallery (hover zoom) ---- */
.ip-gallery{display:grid;grid-template-columns:repeat(5,1fr);gap:14px}
.ip-thumb{position:relative;border-radius:var(--radius-md);overflow:hidden;box-shadow:var(--shadow);background:#edf2f4;cursor:pointer;transition:transform .25s,box-shadow .25s}
.ip-thumb:hover{transform:scale(1.03);box-shadow:var(--shadow-lg);z-index:2}
.ip-thumb img{width:100%;display:block;aspect-ratio:3/4.2;object-fit:cover;object-position:top}
.ip-thumb-title{position:absolute;bottom:0;left:0;right:0;padding:8px 10px;background:linear-gradient(transparent,rgba(0,0,0,.7));color:#fff;font-size:.7rem;line-height:1.3;font-weight:500}
@media(max-width:1000px){.ip-gallery{grid-template-columns:repeat(4,1fr)}}
@media(max-width:768px){.ip-gallery{grid-template-columns:repeat(3,1fr)}}
@media(max-width:480px){.ip-gallery{grid-template-columns:repeat(2,1fr)}}

/* IP Lightbox overlay */
.ip-lightbox{position:fixed;inset:0;z-index:200;background:rgba(0,0,0,.75);backdrop-filter:blur(6px);display:flex;align-items:center;justify-content:center;opacity:0;pointer-events:none;transition:opacity .25s}
.ip-lightbox.is-active{opacity:1;pointer-events:auto}
.ip-lightbox img{max-width:min(520px,90vw);max-height:88vh;border-radius:8px;box-shadow:0 20px 60px rgba(0,0,0,.4)}

/* ---- Paper List ---- */
.paper-list{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}
.paper-card{display:grid;grid-template-columns:56px 1fr;gap:12px;padding:18px;background:var(--paper);border-radius:var(--radius-md);box-shadow:var(--shadow)}
.paper-year{color:var(--accent);font-size:1.2rem;font-weight:800}
.paper-body h3{font-size:.88rem;font-weight:600;line-height:1.4;margin-bottom:4px}
.paper-body p{color:var(--ink-soft);font-size:.82rem;margin:0 0 6px}
.tag{display:inline-block;padding:2px 7px;border-radius:999px;background:var(--steel-soft);color:var(--steel);font-size:.68rem;margin-right:3px}
@media(max-width:640px){.paper-list{grid-template-columns:1fr}.paper-card{grid-template-columns:1fr;gap:6px}}

/* ---- Application Tiles ---- */
.app-tile{padding:18px;border-radius:var(--radius-md);background:var(--paper);box-shadow:var(--shadow);text-align:center}
.app-glyph{display:inline-flex;align-items:center;justify-content:center;width:52px;height:52px;border-radius:14px;background:linear-gradient(135deg,var(--accent-soft),var(--steel-soft));color:var(--accent-deep);font-size:1.2rem;font-weight:800;margin-bottom:8px}
.app-tile strong{display:block;font-size:.9rem}

/* ---- Case Cards ---- */
.case-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}
.case-card{overflow:hidden;background:var(--paper);border-radius:var(--radius-lg);box-shadow:var(--shadow)}
.case-media{aspect-ratio:16/9;background:#0c1418}
.case-media img,.case-media video{width:100%;height:100%;object-fit:cover}
.case-body{padding:20px;display:grid;gap:8px}
@media(max-width:640px){.case-grid{grid-template-columns:1fr}}

/* ---- Code Block ---- */
.code-block{background:#1a2a3a;color:#c8d8e8;border-radius:var(--radius-md);padding:20px;font-family:"JetBrains Mono",Consolas,monospace;font-size:.78rem;line-height:1.6;overflow-x:auto;white-space:pre}
.code-block .kw{color:#7abaff}
.code-block .str{color:#a8d8a8}
.code-block .cmt{color:#6a7a8a}

/* ---- CTA ---- */
.cta-card{background:var(--paper);border-radius:var(--radius-lg);box-shadow:var(--shadow);padding:28px;display:grid;gap:12px}

/* ---- Bullet List ---- */
.bullet-list{padding:0;margin:0;list-style:none;display:grid;gap:8px}
.bullet-list li{position:relative;padding-left:16px;color:var(--ink-soft);font-size:.92rem}
.bullet-list li::before{content:"";position:absolute;top:.72em;left:0;width:6px;height:6px;border-radius:50%;background:var(--accent)}

/* ---- Footer ---- */
.site-footer{padding:24px 0 36px;border-top:1px solid var(--line);margin-top:48px}
.site-footer .wrap{text-align:center;color:var(--ink-soft);font-size:.85rem}
.cta-contact{margin-top:4px}
.cta-contact p{color:var(--ink-soft);font-size:.95rem;line-height:1.8}

/* ---- Reveal Animation ---- */
.reveal{opacity:0;transform:translateY(14px);transition:opacity .4s ease,transform .4s ease}
.reveal.is-visible{opacity:1;transform:translateY(0)}

/* ---- Misc ---- */
.text-link{color:var(--accent-deep);font-weight:600}
.muted{color:var(--ink-soft)}
.mt-sm{margin-top:12px}
.mb-sm{margin-bottom:12px}