/* ============================================================
   robocontrol.dev — v6 Apple-style design system
   White + Fraunces serif + navy accent
   ============================================================ */

:root{
  --ink:#1d1d1f; --body:#3a3a3c; --muted:#6e6e73; --muted2:#86868b;
  --bg:#ffffff; --card:#ffffff; --gray:#f5f5f7; --line:#d2d2d7; --line-soft:rgba(0,0,0,.08);
  --black:#0a0a0a; --on-dark:#f5f5f7; --on-dark-mut:#a1a1a6;
  --accent:#1e3a5f; --accent-d:#142940; --link:#1d3a5c; --link-light:#6f9bd0;
  --serif:"Fraunces",Georgia,"Times New Roman",serif;
  --sans:-apple-system,BlinkMacSystemFont,"SF Pro Display","Inter","Helvetica Neue",Arial,sans-serif;
  --mono:"JetBrains Mono","SF Mono",ui-monospace,monospace;
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--ink);font-family:var(--sans);line-height:1.5;-webkit-font-smoothing:antialiased;letter-spacing:-.003em}
a{color:inherit;text-decoration:none}
.wrap{max-width:1040px;margin:0 auto;padding:0 2rem}
.serif{font-family:var(--serif)}
.mono{font-family:var(--mono)}

/* ---- NAV ---- */
.nav{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.72);backdrop-filter:saturate(180%) blur(20px);-webkit-backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid var(--line-soft)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:50px}
.brand{font-family:var(--serif);font-weight:600;font-size:1.18rem;color:var(--ink);letter-spacing:-.01em}
.brand b{font-weight:600;color:var(--accent)}
.nav ul{display:flex;gap:1.8rem;list-style:none;align-items:center}
.nav ul a{font-size:.84rem;font-weight:400;color:rgba(29,29,31,.7);transition:color .15s}
.nav ul a:hover,.nav ul a.active{color:var(--ink)}
.nav .cta{color:var(--link);font-weight:500}

/* ---- HOMEPAGE HERO ---- */
.hero{padding:clamp(3.5rem,7vw,6rem) 0 clamp(2.5rem,5vw,4rem);text-align:center}
.overline{font-size:.92rem;font-weight:500;color:var(--accent);letter-spacing:.01em;margin-bottom:1rem}
h1.title{font-family:var(--serif);font-weight:600;font-size:clamp(40px,6.4vw,76px);line-height:1.04;letter-spacing:-.025em;color:var(--ink);margin:0 auto .55em;max-width:14ch}
h1.title em{font-style:italic;font-weight:500}
.hero-sub{font-size:clamp(18px,2.1vw,24px);line-height:1.4;color:var(--muted);max-width:32ch;margin:0 auto 1.8rem;font-weight:400}
.cta-row{display:flex;gap:1.6rem;justify-content:center;align-items:center;flex-wrap:wrap}
.pill{background:var(--accent);color:#fff;font-size:1rem;font-weight:500;padding:.74em 1.6em;border-radius:980px;transition:background .15s}
.pill:hover{background:var(--accent-d)}
.text-link{color:var(--link);font-size:1rem}
.text-link:hover{text-decoration:underline}

/* ---- SIM STAGE (dark shell) ---- */
.stage-shell{background:var(--gray);padding:clamp(2.4rem,5vw,3.5rem) 0 clamp(3rem,6vw,5rem)}
.product{max-width:780px;margin:0 auto;background:var(--card);border:1px solid var(--line-soft);border-radius:24px;box-shadow:0 30px 70px -24px rgba(0,0,0,.55);overflow:hidden}
.product-top{display:flex;align-items:center;justify-content:space-between;padding:.95rem 1.4rem;border-bottom:1px solid var(--line-soft)}
.product-top .t{font-size:.82rem;color:var(--muted);font-weight:500}
.product-top .eq{font-family:var(--mono);font-size:.78rem;color:var(--muted2)}
#sim{display:block;width:100%;height:300px;touch-action:none;cursor:grab;background:var(--card)}
#sim.grabbing{cursor:grabbing}
.sim-controls{padding:1.1rem 1.4rem 1.3rem;border-top:1px solid var(--line-soft);background:#fbfbfd}
.ctl-row{display:flex;align-items:center;gap:1rem;flex-wrap:wrap}
.ctl-row label{font-size:.92rem;font-weight:500;color:var(--ink);white-space:nowrap}
.ctl-row .reg{margin-left:auto;font-size:.86rem;font-weight:500;color:var(--accent-d)}
input[type=range]{flex:1;min-width:130px;accent-color:var(--accent);height:5px}
.zval{font-family:var(--mono);font-size:.86rem;font-weight:500;color:var(--ink);min-width:3em;text-align:right}
.minirow{display:flex;gap:.6rem;margin-top:.85rem}
.minibtn{font-size:.86rem;font-weight:400;color:var(--link);background:var(--gray);border:none;padding:.5em 1.05em;border-radius:980px;cursor:pointer;transition:background .15s}
.minibtn:hover{background:#ececef}
.stage-cap{text-align:center;font-size:.86rem;color:var(--muted);margin-top:1.1rem}

/* ---- STATS BAND ---- */
.stats{background:var(--gray);padding:clamp(3rem,6vw,4.5rem) 0}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:1rem;text-align:center}
.stat b{font-family:var(--serif);font-weight:600;font-size:clamp(30px,4.4vw,52px);color:var(--ink);display:block;line-height:1;letter-spacing:-.02em}
.stat span{font-size:.9rem;color:var(--muted);margin-top:.6rem;display:block}

/* ---- SECTIONS ---- */
.sec{padding:clamp(3.5rem,7vw,5.5rem) 0}
.sec.gray{background:var(--gray)}
.sec.dark{background:var(--black)}
.sec-head{text-align:center;margin-bottom:2.6rem}
.sec-head h2{font-family:var(--serif);font-weight:600;font-size:clamp(28px,3.8vw,44px);letter-spacing:-.02em;color:var(--ink)}
.sec-head p{font-size:clamp(16px,1.7vw,19px);color:var(--muted);margin-top:.5rem}
.sec-head.left{text-align:left}
.sec-foot{text-align:center;margin-top:2.4rem}
.sec-foot .text-link{font-size:1.05rem}

/* ---- FEATURE CARD (ME3120 hero) ---- */
.feature{display:grid;grid-template-columns:1.15fr 1fr;background:var(--card);border-radius:22px;overflow:hidden;box-shadow:0 18px 50px -28px rgba(0,0,0,.25);margin-bottom:1.4rem;border:1px solid var(--line-soft)}
.feature .copy{padding:clamp(1.8rem,3vw,2.8rem)}
.feature .code{font-family:var(--mono);font-size:.74rem;letter-spacing:.02em;color:var(--accent-d);text-transform:uppercase;margin-bottom:.7rem;display:block}
.feature h3{font-family:var(--serif);font-weight:600;font-size:clamp(22px,2.6vw,30px);color:var(--ink);letter-spacing:-.01em;line-height:1.15;margin-bottom:.5rem}
.feature p{color:var(--muted);font-size:1rem;margin-bottom:1.1rem;max-width:34ch;line-height:1.55}
.feature .side{background:var(--gray);display:flex;align-items:center;justify-content:center;padding:2rem}
.feature .badge{font-family:var(--serif);font-style:italic;font-size:clamp(18px,2.2vw,26px);color:var(--muted);text-align:center;line-height:1.35}
.feature .badge b{display:block;font-style:normal;font-family:var(--mono);font-size:.76rem;letter-spacing:.06em;color:var(--accent-d);margin-top:.7rem;text-transform:uppercase}
a.feature{transition:box-shadow .2s}
a.feature:hover{box-shadow:0 24px 60px -28px rgba(0,0,0,.35)}

/* ---- COURSE TILES ---- */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:1.4rem}
.tile{background:var(--card);border-radius:18px;padding:1.7rem;box-shadow:0 12px 36px -26px rgba(0,0,0,.25);transition:transform .2s,box-shadow .2s;border:1px solid var(--line-soft)}
.tile:hover{transform:translateY(-3px);box-shadow:0 22px 48px -26px rgba(0,0,0,.35)}
.tile.soon{opacity:.55;pointer-events:none}
.tile .code{font-family:var(--mono);font-size:.74rem;letter-spacing:.02em;color:var(--accent-d);text-transform:uppercase;margin-bottom:.6rem;display:block}
.tile h3{font-family:var(--serif);font-weight:600;font-size:1.28rem;color:var(--ink);letter-spacing:-.01em;margin-bottom:.4rem;line-height:1.2}
.tile p{color:var(--muted);font-size:.92rem;line-height:1.5;margin-bottom:.7rem}
.tile .meta{font-size:.84rem;color:var(--muted2)}
.tile .open{display:inline-block;margin-top:.9rem;color:var(--link);font-size:.92rem}
.tile .soon-tag{display:inline-block;margin-top:.9rem;font-size:.8rem;color:var(--muted2);font-family:var(--mono)}

/* ---- COURSE INDEX: available + coming-soon split ---- */
.cat-label{display:flex;align-items:center;gap:.7rem;font-family:var(--mono);font-size:.76rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted2);margin-bottom:1.4rem}
.cat-label .dot{width:7px;height:7px;border-radius:50%;background:#34c759}
.cat-label.muted .dot{background:var(--muted2)}
.avail-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:1.4rem;margin-bottom:3.5rem}
.course-card{background:var(--card);border:1px solid var(--line-soft);border-radius:18px;padding:1.8rem;box-shadow:0 12px 36px -26px rgba(0,0,0,.25);transition:transform .2s,box-shadow .2s;display:block}
.course-card:hover{transform:translateY(-3px);box-shadow:0 22px 48px -26px rgba(0,0,0,.35)}
.course-card .code{font-family:var(--mono);font-size:.74rem;color:var(--accent-d);text-transform:uppercase;margin-bottom:.6rem;display:block}
.course-card h3{font-family:var(--serif);font-weight:600;font-size:1.4rem;letter-spacing:-.01em;margin-bottom:.5rem;line-height:1.2;color:var(--ink)}
.course-card p{color:var(--muted);font-size:.95rem;line-height:1.5;margin-bottom:1rem}
.course-card .foot{display:flex;justify-content:space-between;align-items:center;border-top:1px solid var(--line-soft);padding-top:.9rem}
.course-card .foot .m{font-size:.84rem;color:var(--muted2)}
.course-card .foot .open{color:var(--link);font-size:.95rem;font-weight:500}
.soon-list{border-top:1px solid var(--line-soft)}
.soon-row{display:grid;grid-template-columns:5.5rem 1fr auto;gap:1.2rem;align-items:center;padding:.95rem .5rem;border-bottom:1px solid var(--line-soft);color:var(--muted)}
.soon-row .code{font-family:var(--mono);font-size:.78rem;color:var(--muted2)}
.soon-row .t{font-family:var(--serif);font-size:1.02rem;font-weight:500;color:var(--body)}
.soon-row .dept{font-size:.78rem;color:var(--muted2);white-space:nowrap}
@media(max-width:560px){.soon-row{grid-template-columns:4.5rem 1fr}.soon-row .dept{display:none}}

/* ---- INNER PAGE HERO ---- */
.page-hero{background:var(--gray);border-bottom:1px solid var(--line-soft);padding:clamp(2.5rem,5vw,4rem) 0}
.breadcrumb{font-family:var(--mono);font-size:.76rem;color:var(--muted2);margin-bottom:1rem;display:flex;gap:.4rem;align-items:center}
.breadcrumb a{color:var(--link)}
.breadcrumb a:hover{text-decoration:underline}
.breadcrumb span{opacity:.4}
.badge-chip{display:inline-block;background:var(--accent);color:#fff;font-family:var(--mono);font-size:.72rem;padding:.3em .85em;border-radius:6px;margin-bottom:.9em;letter-spacing:.05em;font-weight:500}
.page-hero h1{font-family:var(--serif);font-weight:600;font-size:clamp(30px,4.4vw,52px);line-height:1.06;letter-spacing:-.02em;color:var(--ink);margin-bottom:.4em}
.page-hero .sub{color:var(--body);font-size:clamp(15px,1.7vw,19px);max-width:52ch;line-height:1.55}

/* ---- COURSE INDEX (departments) ---- */
.dept-section{margin-bottom:3rem}
.dept-title{font-family:var(--serif);font-weight:600;font-size:clamp(20px,2.4vw,27px);letter-spacing:-.01em;color:var(--ink);margin-bottom:1.2rem;padding-bottom:.7rem;border-bottom:1px solid var(--line)}

/* ---- COURSE PAGE BODY (me3120 lecture list) ---- */
.course-body{max-width:1040px;margin:0 auto;padding:2.5rem 2rem 6rem}
.theme-block{background:var(--card);border:1px solid var(--line-soft);border-radius:18px;margin-bottom:1.4rem;overflow:hidden;box-shadow:0 8px 28px -20px rgba(0,0,0,.18)}
.theme-header{padding:1rem 1.5rem;background:var(--gray);border-bottom:1px solid var(--line-soft);display:flex;align-items:center;gap:.9rem}
.theme-num{width:1.9rem;height:1.9rem;border-radius:50%;background:var(--accent);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:.85rem;flex-shrink:0;font-family:var(--sans)}
.theme-title{font-family:var(--serif);font-weight:600;font-size:clamp(15px,1.7vw,18px);color:var(--ink)}
.lecture-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr))}
.lecture-card{padding:1.15rem 2.4rem 1.15rem 1.5rem;display:flex;flex-direction:column;gap:.3rem;color:inherit;border-right:1px solid var(--line-soft);border-bottom:1px solid var(--line-soft);transition:background .14s;position:relative}
.lecture-card:last-child{border-right:none}
a.lecture-card:hover{background:var(--gray)}
.lecture-card .arrow{position:absolute;right:1rem;top:50%;transform:translateY(-50%);color:var(--accent);font-weight:700;font-size:1.1rem;opacity:0;transition:opacity .14s,right .14s}
a.lecture-card:hover .arrow{opacity:1;right:.75rem}
.lecture-card.soon{opacity:.4;pointer-events:none}
.lecture-num{font-family:var(--mono);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted2)}
.lecture-title{font-size:clamp(14px,1.55vw,16px);font-weight:600;color:var(--ink);line-height:1.3}
.lecture-sub{font-size:.85rem;color:var(--muted);line-height:1.4}

/* ---- ARTICLE / CONTENT (research) ---- */
.content{max-width:740px;margin:0 auto;padding:clamp(2.5rem,5vw,4rem) 2rem 5rem}
.content .lead{font-family:var(--serif);font-size:clamp(18px,2vw,22px);color:var(--ink);line-height:1.5;margin-bottom:1.8rem;font-weight:400}
.content h2{font-family:var(--serif);font-weight:600;font-size:clamp(20px,2.4vw,27px);color:var(--ink);margin:2.4rem 0 .9rem;letter-spacing:-.01em}
.content p{color:var(--body);margin-bottom:1.1rem;font-size:1.02rem;line-height:1.65}
.content a{color:var(--link)}
.content a:hover{text-decoration:underline}
.content ul{margin:0 0 1.2rem 1.2rem;color:var(--body)}
.content li{margin-bottom:.5rem;line-height:1.6}
.content strong{color:var(--ink);font-weight:600}
.fact-list{list-style:none;margin:1.2rem 0;padding:0;display:grid;gap:.6rem}
.fact-list li{display:flex;gap:.8rem;align-items:baseline;border-left:2px solid var(--accent);padding:.25rem 0 .25rem 1rem}
.fact-list .k{font-family:var(--mono);font-size:.78rem;color:var(--accent-d);min-width:6em;letter-spacing:.03em;font-weight:500}

/* ---- FOOTER ---- */
footer.site-footer{background:var(--gray);border-top:1px solid var(--line-soft);padding:2.6rem 0}
.foot-links{display:flex;flex-wrap:wrap;gap:1.8rem;justify-content:center;margin-bottom:1.2rem}
.foot-links a{font-size:.84rem;color:var(--muted);transition:color .15s}
.foot-links a:hover{color:var(--ink)}
.foot-fine{text-align:center;font-size:.8rem;color:var(--muted2);line-height:1.7}
.foot-fine .b{font-family:var(--serif);font-weight:600;color:var(--ink);font-size:.98rem;display:block;margin-bottom:.3rem}

/* ---- RESPONSIVE ---- */
@media(max-width:780px){
  .nav ul li.hide{display:none}
  .feature{grid-template-columns:1fr}
  .feature .side{display:none}
  .stats-grid{grid-template-columns:repeat(2,1fr);gap:2rem 1rem}
}
@media(max-width:600px){
  .lecture-grid{grid-template-columns:1fr}
  .lecture-card{border-right:none}
  .wrap,.content,.course-body{padding-left:1.2rem;padding-right:1.2rem}
}