/* ===== SO-3RE Blog — shared styles (dark brand frame + light reading surface) ===== */
:root{
  --teal:#63dbc6; --orange:#ff9a33; --violet:#bfa3f5; --human:#c4abf2; --yellow:#ffce5a; --coral:#f0604a;
  --orangeD:#d9760f; --violetD:#8a5cf0; --coralD:#d8362a; --tealD:#0f9b82;
  --ink:#1a1029; --ink2:#5a5170; --ink3:#9a90ad; --lineL:rgba(63,0,138,.12);
  --cream:#faf8f4; --card:#ffffff;
  --wink:#fff; --soft:rgba(255,255,255,.66); --faint:rgba(255,255,255,.5);
  --line:rgba(255,255,255,.13); --glass:rgba(255,255,255,.055);
  --maxw:1120px; --e:cubic-bezier(.22,.61,.36,1);
}
*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;color:var(--wink);
  font-family:"Be Vietnam Pro",system-ui,sans-serif;
  font-size:17px;line-height:1.65;-webkit-font-smoothing:antialiased;
  background:
    radial-gradient(70% 60% at 78% 22%, rgba(99,219,198,.16) 0%, transparent 55%),
    radial-gradient(80% 70% at 12% 90%, rgba(122,40,210,.40) 0%, transparent 55%),
    radial-gradient(120% 100% at 50% -10%, #38136f 0%, #25094e 48%, #170632 100%);
  background-attachment:fixed;
}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 28px;position:relative;z-index:2;}

/* language toggle visibility — strong rules so per-class display can't override */
body:not(.lang-vi) [data-vi]{display:none !important;}
body.lang-vi [data-en]{display:none !important;}

/* ===== top bar (same vocabulary as index) ===== */
.topbar{position:sticky;top:0;z-index:10;border-bottom:1px solid var(--line);background:rgba(23,6,50,.55);backdrop-filter:blur(12px) saturate(120%);}
.topbar .wrap{display:flex;justify-content:space-between;align-items:center;height:58px;}
.mark{display:flex;align-items:center;gap:10px;font-weight:800;letter-spacing:-.01em;font-size:16px;white-space:nowrap;color:#fff;text-decoration:none;}
.mark .mk{height:30px;width:30px;object-fit:contain;filter:drop-shadow(0 0 6px rgba(255,255,255,.45));}
.nav{display:flex;align-items:center;gap:16px;}
.nav-link{font-size:13.5px;font-weight:800;color:var(--teal);text-decoration:none;letter-spacing:.02em;white-space:nowrap;transition:opacity .18s;}
.nav-link:hover{opacity:.7;}
.toggle{display:flex;gap:3px;background:rgba(255,255,255,.08);border:1px solid var(--line);border-radius:11px;padding:4px;}
.toggle button{font-family:inherit;font-size:12px;font-weight:800;border:0;background:transparent;color:rgba(255,255,255,.7);padding:6px 13px;border-radius:8px;cursor:pointer;letter-spacing:.03em;transition:all .18s;}
.toggle button[aria-pressed="true"]{background:#fff;color:#3f008a;}

/* ===== post hero (dark) ===== */
.phero{padding:46px 0 30px;}
.lanechip{display:inline-flex;align-items:center;gap:8px;font-size:11.5px;font-weight:800;letter-spacing:.12em;text-transform:uppercase;color:var(--lane);background:color-mix(in srgb,var(--lane) 12%,transparent);border:1px solid color-mix(in srgb,var(--lane) 40%,transparent);border-radius:99px;padding:6px 14px;margin:0 0 18px;}
.lanechip i{width:7px;height:7px;border-radius:50%;background:var(--lane);box-shadow:0 0 10px var(--lane);}
.phero h1{font-weight:900;font-size:clamp(30px,4.6vw,52px);line-height:1.06;letter-spacing:-.03em;margin:0 0 14px;max-width:21ch;}
.pmeta{display:flex;flex-wrap:wrap;align-items:center;gap:10px 18px;font-size:13.5px;color:var(--faint);font-weight:600;}
.pmeta .dot{opacity:.4;}

/* video shell */
.pvideo{margin:26px 0 0;}
.vshell{position:relative;aspect-ratio:16/9;border-radius:18px;overflow:hidden;background:#0b0320;border:1px solid var(--line);box-shadow:0 40px 110px -40px color-mix(in srgb,var(--lane) 60%,transparent);}
.vshell.short{aspect-ratio:9/16;max-width:330px;margin:0 auto;}
.vshell iframe{position:absolute;inset:0;width:100%;height:100%;border:0;}
.vshell .vsoon{position:absolute;inset:0;display:grid;place-items:center;align-content:center;gap:10px;text-align:center;color:var(--soft);}
.vshell .vsoon .pulse{width:52px;height:52px;border-radius:50%;background:color-mix(in srgb,var(--lane) 25%,transparent);border:1px solid var(--lane);display:grid;place-items:center;margin:0 auto;}
.vshell .vsoon .pulse svg{width:20px;height:20px;fill:var(--lane);margin-left:2px;}
.vshell .vsoon p{margin:0;font-size:14px;font-weight:600;}
/* facade: thumbnail + brand play button (player loads on click) */
.vshell .vplay{position:absolute;inset:0;border:0;padding:0;cursor:pointer;background-color:#0b0320;background-size:cover;background-position:center;display:grid;place-items:center;}
.vshell .vplay::before{content:"";position:absolute;inset:0;background:radial-gradient(120% 90% at 50% 50%, transparent 40%, rgba(11,3,32,.55) 100%);}
.vshell .vplay .pbtn{position:relative;width:64px;height:64px;border-radius:50%;background:var(--teal);display:grid;place-items:center;box-shadow:0 0 0 8px rgba(99,219,198,.22),0 18px 50px -12px rgba(0,0,0,.65);transition:transform .25s var(--e);}
.vshell .vplay:hover .pbtn{transform:scale(1.1);}
.vshell .vplay .pbtn svg{width:24px;height:24px;fill:#10322b;margin-left:3px;}
.vshell.short .vplay .pbtn{width:54px;height:54px;}

/* ===== light reading surface ===== */
.doc{background:var(--cream);color:var(--ink);margin-top:34px;border-top:1px solid var(--lineL);}
.docgrid{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:56px;padding:54px 0 64px;}
article{max-width:680px;}
article h2{font-weight:800;font-size:clamp(21px,2.4vw,27px);letter-spacing:-.02em;color:#3f008a;margin:42px 0 14px;scroll-margin-top:80px;}
article h2:first-of-type{margin-top:0;}
article p{margin:0 0 16px;color:var(--ink);font-size:16.5px;}
article p strong{color:#3f008a;}
article ul{margin:0 0 16px;padding-left:22px;}
article li{margin-bottom:8px;font-size:16.5px;}
.epigraph{font-style:italic;font-size:17.5px;color:var(--ink2);border-left:3px solid var(--laneD);padding:4px 0 4px 18px;margin:0 0 30px;}
.epigraph p{margin:0;color:var(--ink2);}
article .callout{border-left:3px solid var(--laneD);background:color-mix(in srgb,var(--laneD) 6%,#fff);padding:14px 18px;border-radius:0 12px 12px 0;margin:0 0 16px;font-size:15.5px;color:var(--ink);}
.sample-note{font-family:"IBM Plex Mono",monospace;font-size:11.5px;color:var(--ink3);border:1px dashed var(--lineL);border-radius:10px;padding:8px 12px;margin:0 0 26px;display:inline-block;}

/* side column (toc + author + lab cta) */
.side{position:sticky;top:84px;align-self:start;display:flex;flex-direction:column;gap:18px;}
.toc{font-size:13.5px;}
.toc .toct{font-size:11px;font-weight:800;letter-spacing:.12em;text-transform:uppercase;color:var(--ink3);margin:0 0 10px;}
.toc a{display:block;color:var(--ink2);text-decoration:none;font-weight:600;padding:6px 0 6px 14px;border-left:2px solid var(--lineL);transition:color .18s,border-color .18s;}
.toc a:hover{color:var(--laneD);border-left-color:var(--laneD);}

/* share row */
.share{display:flex;align-items:center;gap:10px;margin:38px 0 0;padding-top:24px;border-top:1px solid var(--lineL);flex-wrap:wrap;}
.share .sl{font-size:12px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--ink3);margin-right:4px;}
.share button,.share a{display:inline-flex;align-items:center;gap:7px;font-family:inherit;font-size:13px;font-weight:700;color:var(--ink2);background:#fff;border:1px solid var(--lineL);border-radius:99px;padding:8px 16px;cursor:pointer;text-decoration:none;transition:border-color .18s,color .18s,transform .18s;}
.share button:hover,.share a:hover{border-color:var(--laneD);color:var(--laneD);transform:translateY(-1px);}
.share svg{width:15px;height:15px;fill:currentColor;}

/* author box */
.author{display:flex;gap:16px;align-items:center;background:#fff;border:1px solid var(--lineL);border-radius:18px;padding:18px 22px;margin:30px 0 0;box-shadow:0 6px 24px rgba(63,0,138,.06);}
.side .author{flex-direction:column;align-items:center;text-align:center;gap:12px;margin:0;padding:22px 18px;}
.side .author .ava{width:96px;height:96px;font-size:32px;box-shadow:0 0 0 4px color-mix(in srgb,var(--laneD) 16%,transparent);}
.side .author .an{font-size:16.5px;}
.side .author .ar{font-size:12.5px;}
.author .ava{width:58px;height:58px;border-radius:50%;flex:0 0 auto;background:radial-gradient(circle at 50% 35%, #4a1d8f, #2a0b56);color:#fff;display:grid;place-items:center;font-weight:800;font-size:18px;letter-spacing:.02em;overflow:hidden;}
.author .ava img{width:100%;height:100%;object-fit:cover;display:block;}
.author .an{font-weight:800;font-size:15.5px;color:var(--ink);margin:0;}
.author .ar{font-size:13px;color:var(--ink2);margin:2px 0 0;}

/* CTA to Lab */
.labcta{position:relative;overflow:hidden;border-radius:20px;margin:30px 0 0;padding:28px 30px;color:#fff;background:radial-gradient(90% 140% at 85% 0%, rgba(99,219,198,.25) 0%, transparent 50%), linear-gradient(135deg,#3f008a 0%, #25094e 100%);}
.side .labcta{margin:0;padding:20px;border-radius:16px;}
.side .labcta h3{font-size:15.5px;line-height:1.3;}
.side .labcta p{font-size:12.5px;margin-bottom:14px;}
.side .cta{font-size:12.5px;padding:10px 16px;}
.labcta h3{margin:0 0 6px;font-size:20px;font-weight:800;letter-spacing:-.01em;}
.labcta p{margin:0 0 18px;font-size:14.5px;color:var(--soft);max-width:48ch;}
.cta{display:inline-flex;align-items:center;gap:8px;font-weight:800;font-size:14px;padding:12px 20px;border-radius:99px;text-decoration:none;background:var(--teal);color:#10322b;box-shadow:0 16px 40px -18px var(--teal);transition:transform .25s var(--e),box-shadow .25s;}
.cta:hover{transform:translateY(-3px);box-shadow:0 22px 50px -18px var(--teal);}

/* explore-more (YouTube playlist) */
.explore{background:#fff;border:1px solid var(--lineL);border-radius:16px;padding:18px 20px;box-shadow:0 6px 24px rgba(63,0,138,.06);}
.explore .xlbl{display:inline-flex;align-items:center;gap:7px;font-size:10.5px;font-weight:800;letter-spacing:.11em;text-transform:uppercase;color:var(--coralD);margin-bottom:11px;}
.explore .xlbl svg{width:19px;height:19px;flex:0 0 auto;}
.explore h3{margin:0 0 6px;font-size:16px;font-weight:800;color:var(--ink);letter-spacing:-.01em;}
.explore p{margin:0 0 14px;font-size:12.5px;line-height:1.5;color:var(--ink2);}
.explore .xlink{display:inline-flex;align-items:center;gap:7px;font-family:inherit;font-size:12.5px;font-weight:800;color:var(--coralD);text-decoration:none;padding:9px 16px;border:1px solid color-mix(in srgb,var(--coralD) 38%,transparent);border-radius:99px;transition:background .2s var(--e),color .2s var(--e),transform .2s var(--e);}
.explore .xlink:hover{background:var(--coralD);color:#fff;transform:translateY(-1px);}

/* related / prev-next */
.related{margin:38px 0 0;}
.related .rt{font-size:11px;font-weight:800;letter-spacing:.12em;text-transform:uppercase;color:var(--ink3);margin:0 0 12px;}
.relgrid{display:grid;grid-template-columns:1fr 1fr;gap:14px;}
.relcard{display:block;background:#fff;border:1px solid var(--lineL);border-radius:16px;padding:18px 20px;text-decoration:none;transition:transform .25s var(--e),box-shadow .25s,border-color .25s;}
.relcard:hover{transform:translateY(-3px);border-color:var(--rc);box-shadow:0 18px 40px -22px var(--rc);}
.relcard .rl{font-size:10.5px;font-weight:800;letter-spacing:.13em;text-transform:uppercase;color:var(--rc);margin-bottom:6px;}
.relcard .rn{font-weight:800;font-size:15.5px;color:var(--ink);line-height:1.35;}
.relcard .ra{font-size:13px;font-weight:800;color:var(--rc);margin-top:8px;}

/* footer (dark) */
.bfooter{padding:30px 0 48px;}
.bfooter .meta{font-family:"IBM Plex Mono",monospace;font-size:12px;color:var(--faint);letter-spacing:.03em;}

/* ===== hub page ===== */
.pill{display:inline-flex;align-items:center;gap:8px;font-size:11.5px;font-weight:800;letter-spacing:.10em;text-transform:uppercase;color:var(--teal);background:rgba(99,219,198,.1);border:1px solid rgba(99,219,198,.34);border-radius:99px;padding:6px 13px;margin:0 0 20px;}
.pill i{width:7px;height:7px;border-radius:50%;background:var(--teal);box-shadow:0 0 10px var(--teal);animation:blink 2.6s ease-in-out infinite;}
@keyframes blink{0%,100%{opacity:1;}50%{opacity:.35;}}
.hub-hero{padding:60px 0 34px;}
.hub-hero h1{font-weight:900;font-size:clamp(38px,6vw,64px);letter-spacing:-.03em;line-height:1;margin:0 0 14px;}
.hub-hero h1 b{color:var(--teal);}
.hub-hero .sub{font-size:clamp(15px,1.8vw,17.5px);color:var(--soft);max-width:58ch;margin:0;}
.postgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;padding:34px 0 10px;}
.pcard{position:relative;display:flex;flex-direction:column;border-radius:18px;padding:22px 20px 19px;background:var(--glass);border:1px solid var(--line);backdrop-filter:blur(10px);overflow:hidden;color:#fff;text-decoration:none;transition:transform .25s var(--e),box-shadow .25s,border-color .25s;}
.pcard:hover{transform:translateY(-5px);border-color:var(--c);box-shadow:0 22px 50px -26px var(--c);}
.pcard::before{content:"";position:absolute;inset:0 0 auto 0;height:2px;background:linear-gradient(90deg,transparent,var(--c),transparent);opacity:.7;}
.pcard .glow{position:absolute;top:-46px;right:-30px;width:120px;height:120px;border-radius:50%;background:var(--c);filter:blur(50px);opacity:.45;pointer-events:none;}
.pcard .ic{position:relative;width:44px;height:44px;border-radius:12px;display:grid;place-items:center;background:color-mix(in srgb,var(--c) 20%,transparent);border:1px solid color-mix(in srgb,var(--c) 45%,transparent);margin-bottom:13px;}
.pcard .ic svg{width:23px;height:23px;stroke:var(--c);fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round;}
.pcard .pl{position:relative;font-size:10.5px;font-weight:800;letter-spacing:.13em;text-transform:uppercase;color:var(--c);margin-bottom:7px;}
.pcard h3{position:relative;font-size:17px;font-weight:800;letter-spacing:-.015em;margin:0 0 8px;line-height:1.32;text-wrap:balance;min-height:calc(2 * 1.32em);}
.pcard p{position:relative;font-size:13px;line-height:1.5;color:rgba(255,255,255,.66);margin:0 0 16px;flex:1;text-wrap:pretty;}
.pcard .pmrow{position:relative;display:flex;align-items:center;justify-content:space-between;gap:10px;}
.pcard .badge{font-size:10.5px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--soft);background:rgba(255,255,255,.08);border:1px solid var(--line);border-radius:99px;padding:4px 10px;}
.pcard .go{font-size:13.5px;font-weight:800;color:var(--c);}

/* reveal */
.reveal{opacity:0;transform:translateY(10px);animation:rise .7s var(--e) forwards;}
.reveal:nth-child(2){animation-delay:.06s;}
.reveal:nth-child(3){animation-delay:.12s;}
@keyframes rise{to{opacity:1;transform:none;}}
@media (prefers-reduced-motion:reduce){.reveal{animation:none;opacity:1;transform:none;}}
:focus-visible{outline:2px solid var(--teal);outline-offset:3px;border-radius:4px;}

@media (max-width:920px){
  .docgrid{grid-template-columns:1fr;gap:0;}
  .toc{display:none;}
  .side{position:static;margin-top:30px;}
  .postgrid{grid-template-columns:1fr;}
  .relgrid{grid-template-columns:1fr;}
}
@media (max-width:640px){
  .topbar .wrap{padding:8px 14px;height:auto;min-height:52px;flex-wrap:wrap;gap:7px 10px;}
  .mark{font-size:13.5px;gap:7px;}
  .mark .mk{height:22px;width:22px;}
  .nav{gap:8px 12px;flex-wrap:wrap;}
  .nav-link{font-size:11.5px;}
  .toggle{padding:3px;}
  .toggle button{padding:4px 8px;font-size:10.5px;}
  .phero h1{font-size:clamp(26px,7.5vw,38px);}
}