/* ครูกั้มสอนคอม
   Layout: night-mode code editor — deep navy ground with a faint circuit grid, cyan for interaction, gold borrowed from the portrait's glow.
   A deliberate single dark look: every colour below is set explicitly. */
:root{
  --bg:#070b16; --grid:rgba(56,189,248,.055); --surface:#0d1426; --sunk:#131c33; --ink:#e8eefc; --muted:#93a3c3; --line:#1e2a46;
  --accent:#22d3ee; --accent-ink:#03131a; --accent-soft:rgba(34,211,238,.12); --gold:#f6c344;
  --t-teach:#60a5fa; --t-innov:#f6c344; --t-code:#34d399; --t-robot:#a78bfa; --t-ai:#f472b6; --t-design:#fb923c;
  --f-display:"Bai Jamjuree","IBM Plex Sans Thai",system-ui,sans-serif;
  --f-body:"IBM Plex Sans Thai",system-ui,-apple-system,"Segoe UI",sans-serif;
  --f-mono:"IBM Plex Mono",ui-monospace,Menlo,Consolas,monospace;
  --r:14px; --max:1180px; color-scheme:dark;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background-color:var(--bg);color:var(--ink);font-family:var(--f-body);font-size:16px;line-height:1.65;
  background-image:radial-gradient(900px 520px at 85% -10%,rgba(34,211,238,.13),transparent 60%),radial-gradient(700px 500px at -10% 30%,rgba(167,139,250,.10),transparent 60%),
    linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);
  background-size:auto,auto,28px 28px,28px 28px;background-attachment:fixed,fixed,scroll,scroll}
img{max-width:100%}
a{color:var(--accent);text-underline-offset:3px}
h1,h2,h3{font-family:var(--f-display);line-height:1.2;text-wrap:balance;margin:0}
p{margin:0}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:4px}
.wrap{max-width:var(--max);margin:0 auto;padding-inline:20px}
.mono{font-family:var(--f-mono)}
.muted{color:var(--muted)}
.eyebrow{font-family:var(--f-mono);font-size:13px;letter-spacing:.4px;color:var(--muted)}

/* header */
.site-head{position:sticky;top:env(safe-area-inset-top,0px);z-index:10;background:rgba(7,11,22,.82);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.site-head .wrap{display:flex;align-items:center;gap:16px;min-height:60px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);margin-right:auto}
.logo-mark{width:32px;height:32px;border-radius:9px;background:linear-gradient(135deg,var(--accent),#6366f1);display:grid;place-items:center;flex:none;font-family:var(--f-mono);font-weight:600;font-size:13px;color:#fff}
.logo-mark i{display:none}
.logo-mark::after{content:"</>"}
.logo b{font-family:var(--f-display);font-size:19px}
.logo small{font-family:var(--f-mono);font-size:11.5px;color:var(--muted);display:block;line-height:1}
.nav{display:flex;gap:2px}
.nav a{color:var(--muted);text-decoration:none;padding:8px 11px;border-radius:8px;font-size:15px;white-space:nowrap}
.nav a:hover{color:var(--ink);background:var(--sunk)}
.nav a[aria-current=page]{color:var(--ink);font-weight:600}
.nav a.navtool{color:var(--gold);font-weight:600}
.menu-btn{display:none;border:1px solid var(--line);background:var(--surface);border-radius:8px;padding:7px 12px;font:inherit;color:inherit;cursor:pointer}
@media (max-width:900px){
  .menu-btn{display:block}
  .nav{display:none;position:absolute;left:0;right:0;top:100%;flex-direction:column;background:var(--surface);border-bottom:1px solid var(--line);padding:8px 20px 14px}
  .nav.open{display:flex}
  .nav a{padding:11px 4px;border-bottom:1px solid var(--line);border-radius:0}
}

/* home hero */
.hero{padding-block:64px 40px;display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:40px;align-items:center}
@media (max-width:860px){.hero{grid-template-columns:1fr;padding-block:40px 24px}}
.hero h1{font-size:clamp(56px,11vw,128px);font-weight:700;letter-spacing:-1px;line-height:1.15;margin-top:.12em}
.hero h1 span{color:var(--accent)}
.hero .lead{font-size:clamp(18px,2.2vw,21px);max-width:34ch;margin-top:18px}
.hero .chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:22px}
.chip{display:inline-flex;align-items:center;gap:6px;font-size:14px;padding:5px 12px;border-radius:30px;background:var(--surface);border:1px solid var(--line);color:var(--ink);text-decoration:none}
.chip i{width:8px;height:8px;border-radius:50%;background:var(--c,var(--accent))}
.chip:hover{border-color:var(--c,var(--accent))}

/* featured tool card */
.tool-card{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:22px;display:flex;flex-direction:column;gap:14px;box-shadow:0 18px 40px -26px rgba(20,30,60,.35)}
.tool-card .top{display:flex;justify-content:space-between;align-items:center}
.badge{font-family:var(--f-mono);font-size:12px;padding:3px 9px;border-radius:20px;background:var(--accent-soft);color:var(--accent);font-weight:600}
.tool-card h2{font-size:28px}
.sheet-mini{display:grid;grid-template-columns:auto repeat(4,1fr);gap:7px 10px;align-items:center;padding:14px;border-radius:10px;background:var(--sunk);font-family:var(--f-mono);font-size:12.5px;color:var(--muted)}
.sheet-mini .b{width:18px;height:18px;border-radius:50%;border:1.5px solid var(--muted);justify-self:center}
.sheet-mini .b.f{background:var(--ink);border-color:var(--ink)}
.sheet-mini .b.ok{box-shadow:0 0 0 3px color-mix(in srgb,var(--t-code) 55%,transparent)}
.sheet-mini .b.no{box-shadow:0 0 0 3px color-mix(in srgb,#e5402a 60%,transparent)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:11px 18px;border-radius:10px;font-weight:600;text-decoration:none;border:1px solid var(--line);color:var(--ink);background:var(--surface)}
.btn.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.btn:hover{filter:brightness(1.05)}

/* sections */
.section{padding-block:40px}
.sec-head{display:flex;justify-content:space-between;align-items:end;gap:16px;margin-bottom:20px;flex-wrap:wrap}
.sec-head h2{font-size:clamp(24px,3.2vw,32px)}
.topics{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:16px}
.topic{grid-column:span 2;background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:20px;text-decoration:none;color:var(--ink);display:flex;flex-direction:column;gap:10px;transition:border-color .15s,transform .15s}
.topic:hover{border-color:var(--c);transform:translateY(-2px)}
.topic .ic{width:42px;height:42px;border-radius:10px;display:grid;place-items:center;background:color-mix(in srgb,var(--c) 14%,transparent);color:var(--c)}
.topic .ic svg{width:24px;height:24px}
.topic h3{font-size:21px}
.topic p{color:var(--muted);font-size:15px}
.topic .path{margin-top:auto;font-family:var(--f-mono);font-size:12.5px;color:var(--c)}
@media (max-width:860px){.topics{grid-template-columns:1fr 1fr}.topic{grid-column:span 1}}
@media (max-width:520px){.topics{grid-template-columns:1fr}}

/* topic page */
.page-hero{padding-block:48px 28px;border-bottom:1px solid var(--line)}
.page-hero .tag{display:inline-flex;align-items:center;gap:8px;font-family:var(--f-mono);font-size:13px;color:var(--c);font-weight:600}
.page-hero .tag i{width:9px;height:9px;border-radius:50%;background:var(--c)}
.page-hero h1{font-size:clamp(38px,6vw,64px);margin-top:10px}
.page-hero .lead{font-size:19px;max-width:60ch;margin-top:12px;color:var(--muted)}
.draft{display:inline-block;margin-top:14px;font-size:13px;color:var(--muted);border:1px dashed var(--line);padding:4px 10px;border-radius:8px;background:var(--surface)}
.grid2{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(300px,100%),1fr));gap:16px}
.grid3{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(240px,100%),1fr));gap:16px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:20px;min-width:0}
.card h3{font-size:19px;margin-bottom:8px}
.card p,.card li{color:var(--muted);font-size:15.5px}
.card ul,.card ol{margin:8px 0 0;padding-left:20px;display:flex;flex-direction:column;gap:4px}
.card .meta{font-family:var(--f-mono);font-size:12.5px;color:var(--c,var(--accent));margin-bottom:6px}
.path-steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(200px,100%),1fr));gap:0;border:1px solid var(--line);border-radius:var(--r);overflow:hidden;background:var(--surface)}
.path-steps > div{padding:18px;border-right:1px solid var(--line);box-shadow:0 1px 0 var(--line);min-width:0}
.path-steps > div:last-child{border-right:0}
.path-steps .n{font-family:var(--f-mono);font-size:12.5px;color:var(--c)}
.path-steps h3{font-size:18px;margin:4px 0 6px}
.path-steps p{color:var(--muted);font-size:15px}
.links{display:flex;flex-direction:column;border:1px solid var(--line);border-radius:var(--r);background:var(--surface);overflow:hidden}
.links a{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:4px 16px;padding:14px 18px;text-decoration:none;color:var(--ink);border-bottom:1px solid var(--line)}
.links a:last-child{border-bottom:0}
.links a:hover{background:var(--sunk)}
.links a span{color:var(--muted);font-size:14.5px;grid-column:1}
.links a em{font-style:normal;font-family:var(--f-mono);font-size:12.5px;color:var(--muted);grid-row:1;grid-column:2;align-self:center}
.note{border-left:3px solid var(--c,var(--accent));background:var(--surface);padding:14px 18px;border-radius:0 var(--r) var(--r) 0;color:var(--muted)}

/* footer */
.site-foot{border-top:1px solid var(--line);margin-top:48px;padding-block:28px calc(28px + env(safe-area-inset-bottom,0px));font-size:14px;color:var(--muted)}
.site-foot .wrap{display:flex;flex-wrap:wrap;gap:10px 24px;justify-content:space-between}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}

/* ===== Home: hero with portrait ===== */
.hero2{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:28px;align-items:center;padding-block:48px 24px}
.hero2>div{min-width:0}
@media (max-width:900px){.hero2{grid-template-columns:1fr;padding-block:28px 8px}.hero-art{order:-1;max-width:440px;margin-inline:auto}}
.term{display:inline-flex;align-items:center;gap:8px;font-family:var(--f-mono);font-size:13px;color:var(--muted);background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:6px 12px}
.term i{width:9px;height:9px;border-radius:50%;background:#ff5f57}.term i:nth-child(2){background:#febc2e}.term i:nth-child(3){background:#28c840}
.term b{color:var(--t-code);font-weight:500}
.hero2 h1{margin-top:18px;line-height:1.08;font-weight:700;letter-spacing:-.5px}
.hero2 h1 .h1a{display:block;font-size:clamp(54px,9vw,104px)}
.hero2 h1 .h1b{display:block;font-size:clamp(40px,6.4vw,76px);background:linear-gradient(90deg,var(--accent),#818cf8 55%,var(--gold));-webkit-background-clip:text;background-clip:text;color:transparent;padding-bottom:.08em}
.hero2 .lead{font-size:clamp(17px,2vw,20px);color:var(--muted);max-width:36ch;margin-top:14px}
.code-card{margin-top:22px;background:#0a1020;border:1px solid var(--line);border-radius:12px;overflow:hidden;max-width:520px;box-shadow:0 20px 50px -30px rgba(34,211,238,.45)}
.code-card .bar{display:flex;justify-content:space-between;align-items:center;padding:7px 12px;border-bottom:1px solid var(--line);font-family:var(--f-mono);font-size:12px;color:var(--muted)}
.code-card pre{margin:0;padding:14px 16px;font-family:var(--f-mono);font-size:13.5px;line-height:1.7;overflow-x:auto;color:#dbe4ff}
.code-card .k{color:#f472b6}.code-card .f{color:#60a5fa}.code-card .s{color:#34d399}.code-card .c{color:#64748b}.code-card .n{color:var(--gold)}
.caret{display:inline-block;width:8px;height:1.1em;background:var(--accent);vertical-align:-3px;animation:blink 1.1s steps(1) infinite}
@keyframes blink{50%{opacity:0}}
.langs{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}
.lang{font-family:var(--f-mono);font-size:13px;padding:5px 11px;border-radius:8px;border:1px solid var(--line);background:var(--surface);color:var(--ink)}
.lang b{color:var(--c,var(--accent));font-weight:600}
.cta{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}
.btn.gold{background:var(--gold);border-color:var(--gold);color:#1a1300}
.btn.ghost2{background:transparent;border-color:var(--line);color:var(--ink)}
.hero-art{position:relative;aspect-ratio:1/1;width:100%;max-width:100%}
.hero-art .ring{position:absolute;inset:7%;border-radius:50%;background:conic-gradient(from 0deg,rgba(34,211,238,.0),rgba(34,211,238,.55),rgba(246,195,68,.55),rgba(167,139,250,.5),rgba(34,211,238,.0));filter:blur(28px);opacity:.75;animation:spin 18s linear infinite}
.hero-art .disc{position:absolute;inset:16%;border-radius:50%;background:radial-gradient(circle at 50% 40%,#16244a,#0a1122 70%);border:1px solid rgba(34,211,238,.35);box-shadow:inset 0 0 60px rgba(34,211,238,.18)}
.hero-art img{position:absolute;inset:0;width:100%;height:100%;object-fit:contain;filter:drop-shadow(0 18px 30px rgba(0,0,0,.55))}
.ftag{position:absolute;font-family:var(--f-mono);font-weight:600;font-size:clamp(12px,1.4vw,15px);padding:6px 10px;border-radius:10px;background:rgba(13,20,38,.85);border:1px solid var(--line);color:var(--accent);backdrop-filter:blur(4px);animation:bob 5s ease-in-out infinite}
.ftag.t1{left:0;top:18%}.ftag.t2{right:0;top:8%;color:var(--gold);animation-delay:-1.5s}.ftag.t3{right:0;bottom:24%;color:var(--t-ai);animation-delay:-3s}.ftag.t4{left:2%;bottom:12%;color:var(--t-code);animation-delay:-2.2s}
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes bob{50%{transform:translateY(-8px)}}
@media (prefers-reduced-motion:reduce){.hero-art .ring,.ftag,.caret{animation:none}}
.lang-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}
@media (max-width:980px){.lang-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (max-width:560px){.lang-grid{grid-template-columns:1fr 1fr}}
.lcard{text-decoration:none;color:inherit;transition:border-color .15s,transform .15s;background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:16px;display:flex;flex-direction:column;gap:6px;min-width:0;position:relative;overflow:hidden}
.lcard::before{content:"";position:absolute;inset:0 0 auto 0;height:3px;background:var(--c)}
.lcard .ext{font-family:var(--f-mono);font-size:12px;color:var(--c)}
.lcard h3{font-size:18px}
.lcard p{font-size:14px;color:var(--muted)}
.lcard .lv{margin-top:auto;font-family:var(--f-mono);font-size:12px;color:var(--muted)}
.tools{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media (max-width:760px){.tools{grid-template-columns:1fr}}
.tool{display:grid;grid-template-columns:auto minmax(0,1fr);gap:16px;align-items:center;background:linear-gradient(135deg,var(--surface),#101a33);border:1px solid var(--line);border-radius:16px;padding:20px;text-decoration:none;color:var(--ink);transition:border-color .15s,transform .15s}
.tool:hover{border-color:var(--c);transform:translateY(-2px)}
.tool .ti{width:56px;height:56px;border-radius:14px;display:grid;place-items:center;background:color-mix(in srgb,var(--c) 16%,transparent);color:var(--c)}
.tool .ti svg{width:30px;height:30px}
.tool h3{font-size:21px}
.tool p{color:var(--muted);font-size:15px}
.tool .go{font-family:var(--f-mono);font-size:13px;color:var(--c);margin-top:4px;display:inline-block}

.lcard:hover{border-color:var(--c);transform:translateY(-2px)}