/* ============================================================
   lecture.css — shared styling for husainalkhaldy.com/lectures
   Extends the site's "sunrise gold / thin-air blue" dark theme.
   Kept isolated so it can be re-skinned in one file.
   ============================================================ */
:root{
  --bg:#0a0f1e; --bg-2:#0c1224; --elev:#111a33;
  --surface:rgba(255,255,255,.028); --surface-2:rgba(255,255,255,.05);
  --line:rgba(255,255,255,.09); --line-strong:rgba(255,255,255,.16);
  --text:#eaeefb; --muted:#98a2c2; --faint:#657092;
  --accent:#e9b45c; --accent-soft:#f0c884; --ice:#84b9d8;
  --maxw:1080px; --ease:cubic-bezier(.2,.7,.2,1);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  background:var(--bg); color:var(--text);
  font-family:"Instrument Sans",system-ui,sans-serif;
  font-size:clamp(15px,1.02vw,17px); line-height:1.65; letter-spacing:-.005em;
  overflow-x:hidden; -webkit-font-smoothing:antialiased;
}
::selection{background:var(--accent);color:#1a1205}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}

/* ---------- atmosphere ---------- */
.atmos{position:fixed;inset:0;z-index:-2;overflow:hidden;pointer-events:none}
.glow{position:absolute;left:50%;top:-14%;width:120vw;height:70vh;transform:translateX(-50%);
  background:radial-gradient(60% 60% at 50% 40%,rgba(233,180,92,.14),rgba(233,180,92,.03) 40%,transparent 70%);filter:blur(6px)}
.horizon{position:absolute;left:50%;bottom:-34vh;width:140vw;height:70vh;transform:translateX(-50%);
  background:radial-gradient(50% 60% at 50% 100%,rgba(132,185,216,.09),transparent 70%)}
.grain{position:fixed;inset:0;z-index:-1;pointer-events:none;opacity:.045;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E")}

/* ---------- layout ---------- */
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 clamp(20px,5vw,48px)}
.eyebrow{font-family:"Space Mono",monospace;font-size:.72rem;letter-spacing:.24em;text-transform:uppercase;
  color:var(--accent);display:inline-flex;align-items:center;gap:.7em}
.eyebrow::before{content:"";width:24px;height:1px;background:var(--accent);opacity:.6}

/* ---------- nav ---------- */
header{position:fixed;top:0;left:0;right:0;z-index:60;transition:background .4s,backdrop-filter .4s,border-color .4s;border-bottom:1px solid transparent}
header.scrolled{background:rgba(10,15,30,.72);backdrop-filter:blur(14px) saturate(120%);border-color:var(--line)}
nav.top{max-width:var(--maxw);margin:0 auto;padding:16px clamp(20px,5vw,48px);display:flex;align-items:center;justify-content:space-between}
.mark{display:flex;align-items:center;gap:.6em;font-family:"Fraunces",serif;font-weight:600;font-size:1.02rem;letter-spacing:-.02em;color:var(--text)}
.mark .wm{font-weight:600;white-space:nowrap}
.mark i{color:var(--accent);font-style:normal}
.mark svg{width:24px;height:24px;flex:none}
.navlinks{display:flex;gap:1.6em;align-items:center}
.navlinks a{color:var(--muted);font-size:.88rem;position:relative;transition:color .25s}
.navlinks a::after{content:"";position:absolute;left:0;bottom:-5px;width:0;height:1px;background:var(--accent);transition:width .3s var(--ease)}
.navlinks a:hover{color:var(--text)}
.navlinks a:hover::after{width:100%}
.navlinks .cta{color:var(--accent)}

/* hamburger + full-screen mobile menu (matches homepage) */
.menu-btn{display:none;position:relative;width:44px;height:44px;padding:0;border:0;background:none;cursor:pointer;-webkit-tap-highlight-color:transparent;z-index:60;flex:none}
.menu-btn span{position:absolute;left:11px;right:11px;height:2px;border-radius:2px;background:var(--text);transition:transform .35s var(--ease),opacity .2s var(--ease)}
.menu-btn span:nth-child(1){top:16px}.menu-btn span:nth-child(2){top:22px}.menu-btn span:nth-child(3){top:28px}
body.menu-open .menu-btn span:nth-child(1){transform:translateY(6px) rotate(45deg)}
body.menu-open .menu-btn span:nth-child(2){opacity:0}
body.menu-open .menu-btn span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}
.mobile-menu{position:fixed;inset:0;z-index:55;display:flex;flex-direction:column;justify-content:center;
  padding:calc(env(safe-area-inset-top) + 92px) clamp(28px,8vw,56px) calc(env(safe-area-inset-bottom) + 40px);
  background:rgba(10,15,30,.86);backdrop-filter:blur(22px) saturate(120%);-webkit-backdrop-filter:blur(22px) saturate(120%);
  opacity:0;visibility:hidden;transition:opacity .42s var(--ease),visibility .42s var(--ease)}
body.menu-open .mobile-menu{opacity:1;visibility:visible}
body.menu-open{overflow:hidden}
body.menu-open header{z-index:60}
.mm-inner{display:flex;flex-direction:column;gap:.1em}
.mobile-menu a{font-family:"Fraunces",serif;font-weight:400;font-size:clamp(2rem,8.5vw,2.7rem);letter-spacing:-.02em;color:var(--text);padding:.26em 0;line-height:1.1;opacity:0;transform:translateY(16px);transition:opacity .5s var(--ease),transform .5s var(--ease),color .25s}
.mobile-menu a:active{color:var(--accent)}
body.menu-open .mobile-menu a{opacity:1;transform:none}
body.menu-open .mobile-menu a:nth-child(1){transition-delay:.05s}
body.menu-open .mobile-menu a:nth-child(2){transition-delay:.10s}
body.menu-open .mobile-menu a:nth-child(3){transition-delay:.15s}
body.menu-open .mobile-menu a:nth-child(4){transition-delay:.20s}
body.menu-open .mobile-menu a:nth-child(5){transition-delay:.25s}
body.menu-open .mobile-menu a:nth-child(6){transition-delay:.30s}
@media(max-width:820px){.navlinks{display:none}.menu-btn{display:block}}
@media(min-width:821px){.mobile-menu{display:none}}
@media(prefers-reduced-motion:reduce){.mobile-menu,.mobile-menu a,.menu-btn span{transition:none}.mobile-menu a{opacity:1;transform:none}}

/* ---------- hero ---------- */
.lec-hero{padding:clamp(128px,20vh,190px) 0 clamp(30px,5vh,52px)}
.lec-hero .coords{font-family:"Space Mono",monospace;font-size:.74rem;letter-spacing:.14em;color:var(--faint);margin-bottom:1.7em;display:inline-flex;gap:.8em;flex-wrap:wrap;align-items:center}
.lec-hero .coords b{color:var(--ice);font-weight:400}
.lec-hero h1{font-family:"Fraunces",serif;font-weight:420;font-optical-sizing:auto;
  font-size:clamp(2.3rem,6vw,4.4rem);line-height:1.0;letter-spacing:-.032em;color:#f5f7fe;margin:.1em 0 .34em;max-width:16ch}
.lec-hero h1 em{font-style:italic;color:var(--accent)}
.lec-hero .sub{font-family:"Fraunces",serif;font-size:clamp(1.1rem,2.2vw,1.5rem);font-style:italic;color:var(--muted);max-width:40ch;line-height:1.4}
.lec-meta{margin-top:1.8em;display:flex;flex-wrap:wrap;gap:.6em 1.4em;font-family:"Space Mono",monospace;font-size:.76rem;letter-spacing:.06em;color:var(--faint)}
.lec-meta .dot{color:var(--accent)}
.dl-row{display:flex;flex-wrap:wrap;gap:10px;margin-top:1.8em}
.btn{display:inline-flex;align-items:center;gap:.55em;padding:.72em 1.25em;border-radius:100px;font-size:.86rem;font-weight:500;transition:transform .3s var(--ease),background .3s,border-color .3s,color .3s;cursor:pointer}
.btn svg{width:15px;height:15px}
.btn-primary{background:var(--accent);color:#1a1205;border:1px solid var(--accent)}
.btn-primary:hover{background:var(--accent-soft);transform:translateY(-2px)}
.btn-ghost{color:var(--text);border:1px solid var(--line-strong)}
.btn-ghost:hover{border-color:var(--accent);color:var(--accent);transform:translateY(-2px)}

/* ---------- sticky sub-nav (progress + parts) ---------- */
.lec-subnav{position:sticky;top:0;z-index:40;background:rgba(10,15,30,.78);backdrop-filter:blur(14px) saturate(120%);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.lec-subnav .bar{max-width:var(--maxw);margin:0 auto;padding:11px clamp(20px,5vw,48px);display:flex;align-items:center;gap:1.4em;flex-wrap:wrap}
.parts{display:flex;gap:.5em;flex-wrap:wrap}
.parts a{font-family:"Space Mono",monospace;font-size:.74rem;letter-spacing:.05em;color:var(--muted);padding:.4em .85em;border:1px solid var(--line);border-radius:100px;transition:.25s}
.parts a:hover{color:var(--text);border-color:var(--line-strong)}
.parts a.active{color:var(--accent);border-color:var(--accent)}
.progress-track{flex:1;min-width:80px;height:2px;background:var(--line);border-radius:2px;overflow:hidden}
.progress-fill{height:100%;width:0;background:linear-gradient(90deg,var(--accent),var(--accent-soft));transition:width .15s linear}
.progress-pct{font-family:"Space Mono",monospace;font-size:.72rem;color:var(--faint);min-width:3.2em;text-align:right}

/* ---------- parts + slides ---------- */
.lec-part{padding:clamp(40px,7vh,72px) 0 0}
.part-head{display:flex;align-items:baseline;gap:1em;margin-bottom:1.6em;padding-top:.4em}
.part-head .pn{font-family:"Space Mono",monospace;font-size:.8rem;color:var(--accent);letter-spacing:.1em}
.part-head h2{font-family:"Fraunces",serif;font-weight:400;font-size:clamp(1.5rem,3.2vw,2.2rem);letter-spacing:-.025em;line-height:1.1;color:#f2f5ff}

.slide{margin:0 0 clamp(30px,5vh,52px);scroll-margin-top:88px}
.paper{position:relative;border-radius:16px;overflow:hidden;background:#fff;
  border:1px solid var(--line-strong);box-shadow:0 24px 60px -28px rgba(0,0,0,.7),0 2px 8px rgba(0,0,0,.3);
  cursor:zoom-in;transition:transform .4s var(--ease),box-shadow .4s}
.paper:hover{transform:translateY(-3px);box-shadow:0 34px 74px -30px rgba(0,0,0,.78),0 3px 10px rgba(0,0,0,.35)}
.paper img{width:100%;height:auto;background:#fff}
.paper .zoomcue{position:absolute;top:12px;right:12px;width:32px;height:32px;border-radius:50%;
  background:rgba(10,15,30,.55);backdrop-filter:blur(6px);display:flex;align-items:center;justify-content:center;
  opacity:0;transition:opacity .3s}
.paper:hover .zoomcue{opacity:1}
.paper .zoomcue svg{width:16px;height:16px;stroke:#fff}

figure.slide figcaption{margin-top:14px;display:grid;grid-template-columns:auto 1fr;gap:1em;align-items:start}
.snum{font-family:"Space Mono",monospace;font-size:.74rem;color:var(--accent);letter-spacing:.05em;padding-top:.15em;white-space:nowrap}
.trans{color:var(--muted);border-left:2px solid var(--line);padding-left:1.1em}
.trans h4{font-family:"Fraunces",serif;font-weight:500;font-size:1.12rem;color:var(--text);letter-spacing:-.01em;line-height:1.25;margin:0 0 .45em}
.trans p{margin:0 0 .6em;font-size:.95rem}
.trans p:last-child{margin-bottom:0}
.trans strong{color:var(--text);font-weight:600}
.trans em{color:var(--ice);font-style:italic}
.trans ul{margin:.2em 0 .7em;padding-left:1.15em}
.trans li{margin:.28em 0;font-size:.94rem}
.trans li::marker{color:var(--accent)}
.trans table{width:100%;border-collapse:collapse;margin:.5em 0 .8em;font-size:.88rem}
.trans th,.trans td{border:1px solid var(--line);padding:.5em .7em;text-align:left;vertical-align:top}
.trans thead th{background:var(--surface-2);color:var(--text);font-weight:600;font-family:"Space Mono",monospace;font-size:.74rem;letter-spacing:.03em;text-transform:uppercase}
.trans td{color:var(--muted)}
@media(max-width:640px){
  figure.slide figcaption{grid-template-columns:1fr;gap:.5em}
  .trans{border-left:none;padding-left:0}
  .snum{padding-top:0}
}

/* ---------- lightbox ---------- */
.lb{position:fixed;inset:0;z-index:100;background:rgba(6,9,18,.94);backdrop-filter:blur(8px);
  display:flex;align-items:center;justify-content:center;padding:24px;opacity:0;pointer-events:none;transition:opacity .3s}
.lb.open{opacity:1;pointer-events:auto}
.lb img{max-width:96vw;max-height:92vh;width:auto;border-radius:10px;box-shadow:0 30px 80px rgba(0,0,0,.6);cursor:zoom-out;background:#fff}
.lb .lb-close{position:absolute;top:18px;right:22px;width:42px;height:42px;border-radius:50%;border:1px solid var(--line-strong);
  background:rgba(20,26,44,.6);color:var(--text);font-size:1.3rem;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:.25s}
.lb .lb-close:hover{border-color:var(--accent);color:var(--accent)}
.lb .lb-nav{position:absolute;top:50%;transform:translateY(-50%);width:46px;height:46px;border-radius:50%;
  border:1px solid var(--line-strong);background:rgba(20,26,44,.6);color:var(--text);display:flex;align-items:center;justify-content:center;cursor:pointer;transition:.25s;user-select:none}
.lb .lb-nav:hover{border-color:var(--accent);color:var(--accent)}
.lb .lb-prev{left:18px}.lb .lb-next{right:18px}
.lb .lb-count{position:absolute;bottom:20px;left:50%;transform:translateX(-50%);font-family:"Space Mono",monospace;font-size:.78rem;color:var(--muted);letter-spacing:.06em}
@media(max-width:640px){.lb .lb-nav{display:none}}

/* ---------- footer ---------- */
footer{border-top:1px solid var(--line);padding:2.4em 0;margin-top:clamp(50px,9vh,90px)}
.foot{display:flex;justify-content:space-between;align-items:center;gap:1.4em;flex-wrap:wrap;color:var(--faint);font-size:.82rem}
.foot a{color:var(--muted);transition:color .25s}.foot a:hover{color:var(--accent)}
.foot .mono{font-family:"Space Mono",monospace;letter-spacing:.06em}

/* ---------- reveal ---------- */
.reveal{opacity:0;transform:translateY(22px);transition:opacity .9s var(--ease),transform .9s var(--ease)}
.reveal.in{opacity:1;transform:none}
@media(prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}html{scroll-behavior:auto}.paper:hover{transform:none}}

/* ============================================================
   /lectures index (hub) grid
   ============================================================ */
.hub-hero{padding:clamp(128px,20vh,200px) 0 clamp(24px,4vh,40px)}
.hub-hero h1{font-family:"Fraunces",serif;font-weight:420;font-size:clamp(2.4rem,7vw,4.6rem);line-height:.98;letter-spacing:-.035em;color:#f5f7fe;margin:.12em 0 .3em}
.hub-hero h1 em{font-style:italic;color:var(--accent)}
.hub-hero .lede{font-size:clamp(1.02rem,2vw,1.28rem);color:var(--muted);max-width:52ch;line-height:1.5}
.hub-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px;padding:clamp(24px,5vh,48px) 0 0}
@media(max-width:720px){.hub-grid{grid-template-columns:1fr}}
a.lcard{position:relative;display:grid;grid-template-rows:auto 1fr;border:1px solid var(--line);border-radius:18px;background:var(--surface);overflow:hidden;transition:transform .4s var(--ease),border-color .4s,background .4s}
a.lcard:hover{transform:translateY(-5px);border-color:var(--line-strong);background:var(--surface-2)}
.lcard .thumb{aspect-ratio:2752/1536;background:#fff;overflow:hidden;border-bottom:1px solid var(--line)}
.lcard .thumb img{width:100%;height:100%;object-fit:cover;object-position:center top;transition:transform .5s var(--ease)}
a.lcard:hover .thumb img{transform:scale(1.03)}
.lcard .body{padding:1.5em 1.6em 1.7em;display:flex;flex-direction:column;gap:.55em}
.lcard .meta{display:flex;align-items:center;gap:.7em;flex-wrap:wrap}
.lcard .year{font-family:"Space Mono",monospace;font-size:.72rem;color:var(--accent);letter-spacing:.1em}
.tag{font-family:"Space Mono",monospace;font-size:.62rem;letter-spacing:.13em;text-transform:uppercase;color:var(--faint);border:1px solid var(--line);border-radius:100px;padding:.32em .75em}
.lcard h3{font-family:"Fraunces",serif;font-weight:450;font-size:1.42rem;letter-spacing:-.02em;line-height:1.15}
.lcard p{color:var(--muted);font-size:.95rem;line-height:1.5}
.lcard .go{margin-top:auto;padding-top:.5em;font-family:"Space Mono",monospace;font-size:.75rem;letter-spacing:.06em;color:var(--text);display:inline-flex;align-items:center;gap:.5em}
.lcard .go .arw{color:var(--accent);transition:transform .25s var(--ease)}
a.lcard:hover .go .arw{transform:translateX(4px)}
.lcard.soon{border-style:dashed;background:transparent;pointer-events:none}
.lcard.soon .body{padding:1.8em 1.6em}
.lcard.soon h3{color:var(--faint);font-style:italic}
.hub-note{margin-top:2em;font-family:"Space Mono",monospace;font-size:.78rem;color:var(--faint);letter-spacing:.05em}