/* EE Labs kit stylesheet, forked from DemoPlayer: an instrument rack (nav, screens, knob panel).
   Every colour is a token the lab sets on :root:
   --bg --panel-a --panel-b --well --well2 --line --line2 --ink --muted --dim --screen --bezel-line --bezel-0 --bezel-1
   --ch1..--ch5 --warn --on-ch1 --on-ch3 --f-ui --f-num, and --glow (1 = phosphor glow, 0 = flat ink on paper). */
*{box-sizing:border-box}
html{background:var(--bg)}
body{margin:0;background:
  radial-gradient(900px 500px at 75% -10%, color-mix(in srgb,var(--ch1) 7%,transparent), transparent 60%),
  radial-gradient(700px 400px at -10% 30%, color-mix(in srgb,var(--ch3) 4%,transparent), transparent 60%), var(--bg);
  color:var(--ink);font:15px/1.5 var(--f-ui);-webkit-font-smoothing:antialiased}
body::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);z-index:30;background:var(--bg)}
a{color:var(--ch3)}
button,select,input{font:inherit}
:focus-visible{outline:2px solid var(--ch3);outline-offset:2px}

/* header */
.top{position:sticky;top:env(safe-area-inset-top,0px);z-index:20;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.topin{display:flex;align-items:center;gap:14px;padding-block:10px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:inherit;min-width:0}
.brand svg{flex:none}
.logo{font:700 21px/1 var(--f-ui);letter-spacing:.03em;color:var(--ch1);text-shadow:0 0 14px color-mix(in srgb,var(--ch1) 55%,transparent)}
.tag{font-size:12px;color:var(--muted);letter-spacing:.04em;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.edition{margin-left:auto;font:500 11px var(--f-num);color:var(--dim);letter-spacing:.08em;text-transform:uppercase;white-space:nowrap}

/* rack */
.app{display:grid;grid-template-columns:212px minmax(0,1fr);gap:24px;max-width:1500px;margin:0 auto;
  padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px));padding-block:20px 40px}
nav#nav{position:sticky;top:calc(env(safe-area-inset-top,0px) + 64px);align-self:start;display:flex;flex-direction:column;gap:16px;max-height:calc(100vh - 84px);overflow:auto;scrollbar-width:thin}
.ng{display:flex;flex-direction:column;gap:2px}
.ngt{font:600 10px var(--f-ui);letter-spacing:.16em;text-transform:uppercase;color:var(--dim);padding:0 10px 4px}
.nl{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:7px 10px;border-radius:7px;color:var(--muted);text-decoration:none;border:1px solid transparent;font-weight:500;font-size:14px}
.nl:hover{color:var(--ink);background:color-mix(in srgb,var(--ch1) 4%,transparent)}
.nl[aria-current="page"]{color:var(--ch1);border-color:color-mix(in srgb,var(--ch1) 35%,transparent);background:color-mix(in srgb,var(--ch1) 7%,transparent);box-shadow:inset 0 0 14px color-mix(in srgb,var(--ch1) 10%,transparent)}
.lv{font:500 10px var(--f-num);letter-spacing:.04em;color:var(--dim);border:1px solid var(--line2);border-radius:4px;padding:1px 5px;white-space:nowrap}
.nl[aria-current="page"] .lv{color:var(--ch1);border-color:color-mix(in srgb,var(--ch1) 35%,transparent)}

main{min-width:0;display:flex;flex-direction:column;gap:18px}
#intro{display:flex;flex-direction:column;gap:6px;max-width:80ch}
.eyebrow{display:flex;gap:10px;align-items:center;font:600 11px var(--f-ui);letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}
#intro h1{margin:0;font:700 clamp(26px,3.2vw,38px)/1.1 var(--f-ui);letter-spacing:.01em;text-wrap:balance;color:var(--ink)}
#intro .sub{margin:0;color:var(--muted);font-size:16px;max-width:70ch;text-wrap:pretty}
.bench{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:20px;align-items:start}
body.full .bench{grid-template-columns:minmax(0,1fr)}
#screens{display:flex;flex-direction:column;gap:18px;min-width:0}
.pair{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}
.trio{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}

/* screens */
.screen{margin:0;display:flex;flex-direction:column;gap:7px;min-width:0}
.bezel{position:relative;width:100%;max-width:100%;border-radius:10px;background:var(--screen);border:1px solid var(--bezel-line);overflow:hidden;
  box-shadow:inset 0 0 0 1px rgba(0,0,0,.6),0 0 0 4px var(--bezel-0),0 0 0 5px var(--bezel-1),0 14px 34px rgba(0,0,0,.55)}
.bezel::after{content:"";position:absolute;inset:0;pointer-events:none;border-radius:inherit;
  background:radial-gradient(120% 120% at 50% 50%, transparent 62%, rgba(0,0,0,.55) 100%),
  repeating-linear-gradient(0deg, rgba(255,255,255,.012) 0 1px, transparent 1px 3px)}
.bezel canvas{display:block;width:100%;height:100%}
.bezel canvas.drag{cursor:grab;touch-action:pan-y}
.glcv{cursor:grab}.glcv.grab{cursor:grabbing}
.bezel .hud{position:absolute;left:10px;top:8px;font:11px var(--f-num);color:var(--muted);pointer-events:none;z-index:2;text-shadow:0 0 6px #000}
.bezel .hud.r{left:auto;right:10px}
.bezel .hud.b{top:auto;bottom:8px}
figcaption{display:flex;flex-wrap:wrap;align-items:baseline;gap:6px 16px;padding:0 4px}
.sn{font:600 12.5px var(--f-ui);letter-spacing:.04em;color:var(--muted)}
.leg{display:flex;flex-wrap:wrap;gap:4px 14px}
.chip{display:inline-flex;align-items:center;gap:6px;font:12px var(--f-num);color:var(--c)}
.chip::before{content:"";width:14px;height:2px;border-radius:1px;background:var(--c);box-shadow:0 0 6px var(--c)}

/* knob panel */
#panel{background:linear-gradient(180deg,var(--panel-a),var(--panel-b));border:1px solid var(--line);border-radius:12px;padding:16px;display:flex;flex-direction:column;gap:18px;min-width:0;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.03)}
.grp{display:flex;flex-direction:column;gap:10px;min-width:0}
.grp+.grp{border-top:1px solid var(--line);padding-top:16px}
.grp h3{margin:0;font:600 11px var(--f-ui);letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}
.knob{display:flex;flex-direction:column;gap:2px}
.knob.off{opacity:.4}
.kl{display:flex;justify-content:space-between;gap:10px;font-size:13.5px;color:var(--ink)}
.val{font:500 13px var(--f-num);color:var(--ch1);white-space:nowrap;font-variant-numeric:tabular-nums}
input[type=range]{-webkit-appearance:none;appearance:none;width:100%;height:24px;background:transparent;margin:0;cursor:pointer}
input[type=range]::-webkit-slider-runnable-track{height:4px;border-radius:2px;background:linear-gradient(90deg,color-mix(in srgb,var(--ch1) 55%,transparent),color-mix(in srgb,var(--ch1) 14%,transparent))}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:18px;height:18px;margin-top:-7px;border-radius:50%;background:var(--well);border:2px solid var(--ch1);box-shadow:0 0 10px color-mix(in srgb,var(--ch1) 60%,transparent)}
input[type=range]::-moz-range-track{height:4px;border-radius:2px;background:linear-gradient(90deg,color-mix(in srgb,var(--ch1) 55%,transparent),color-mix(in srgb,var(--ch1) 14%,transparent))}
input[type=range]::-moz-range-thumb{width:14px;height:14px;border-radius:50%;background:var(--well);border:2px solid var(--ch1);box-shadow:0 0 10px color-mix(in srgb,var(--ch1) 60%,transparent)}
.field{display:flex;flex-direction:column;gap:5px;min-width:0}
.fl{font-size:13.5px;color:var(--ink)}
.segs{display:flex;flex-wrap:wrap;gap:4px}
.sg,.btn{flex:1 1 auto;font:600 12.5px var(--f-ui);letter-spacing:.04em;padding:7px 9px;border-radius:7px;border:1px solid var(--line2);background:var(--well);color:var(--muted);cursor:pointer;white-space:nowrap}
.sg:hover,.btn:hover{color:var(--ink);border-color:color-mix(in srgb,var(--ch1) 40%,transparent)}
.sg[aria-pressed="true"]{color:var(--on-ch1);background:var(--ch1);border-color:var(--ch1);box-shadow:0 0 14px color-mix(in srgb,var(--ch1) 45%,transparent)}
.btn.primary{color:var(--ch1);border-color:color-mix(in srgb,var(--ch1) 55%,transparent);background:color-mix(in srgb,var(--ch1) 8%,transparent)}
.brow{display:flex;flex-wrap:wrap;gap:6px}
select{width:100%;padding:7px 10px;border-radius:7px;border:1px solid var(--line2);background:var(--well);color:var(--ink)}
.ro{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin:0}
.ro div{background:var(--well2);border:1px solid var(--line);border-radius:8px;padding:7px 10px;min-width:0}
.ro dt{font:500 11.5px var(--f-ui);letter-spacing:.02em;color:var(--muted)}
.ro dd{margin:0;font:600 15px var(--f-num);color:var(--ch1);font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.note{margin:0;font-size:13.5px;line-height:1.55;color:var(--muted);text-wrap:pretty}
.note b{color:var(--ink);font-weight:600}
.warn{color:var(--warn)}
.formula{margin:0;font:13px/1.5 var(--f-num);color:var(--ch2);background:var(--well2);border:1px solid var(--line);border-radius:7px;padding:7px 10px;white-space:pre-wrap;overflow-wrap:anywhere}
.tries{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:8px}
.tries li{position:relative;padding-left:18px;font-size:13.5px;color:var(--muted);line-height:1.5}
.tries li::before{content:"";position:absolute;left:2px;top:.55em;width:7px;height:7px;border-radius:50%;background:var(--ch1);box-shadow:0 0 8px var(--ch1)}

/* language switch */
.langs{display:flex;gap:2px;flex:none;border:1px solid var(--line2);border-radius:8px;padding:2px;background:var(--well)}
.lg{font:600 12px var(--f-ui);letter-spacing:.04em;color:var(--muted);background:transparent;border:0;border-radius:6px;padding:5px 9px;cursor:pointer}
.lg[aria-pressed="true"]{color:var(--on-ch1);background:var(--ch1)}
@media (max-width:440px){.brand svg{display:none}.lg{padding:5px 7px}.topin{gap:8px}}
/* level switch under the title */
.levelsw{margin-top:6px;max-width:420px}
/* guided lesson card */
.ls-card{display:flex;flex-direction:column;gap:12px}
.ls-top{display:flex;justify-content:space-between;align-items:center;gap:10px}
.ls-step{font:600 11px var(--f-ui);letter-spacing:.16em;text-transform:uppercase;color:var(--ch2)}
.ls-dots{display:flex;gap:5px}
.ls-dot{width:10px;height:10px;border-radius:50%;border:1.5px solid var(--line2);background:transparent;padding:0;cursor:pointer}
.ls-dot[aria-current="true"]{background:var(--ch1);border-color:var(--ch1);box-shadow:0 0 8px var(--ch1)}
.ls-title{margin:0;font:700 22px/1.2 var(--f-ui);color:var(--ink);text-wrap:balance}
.ls-text{display:flex;flex-direction:column;gap:9px}
.ls-text p{margin:0;font-size:15px;line-height:1.6;color:var(--ink);text-wrap:pretty}
.ls-controls{display:flex;flex-direction:column;gap:10px}
.ls-controls:empty{display:none}
.ls-controls .btn,.ls-nav .btn{white-space:normal;text-align:center;line-height:1.35}
.ls-ask details{border:1px dashed color-mix(in srgb,var(--ch2) 45%,transparent);border-radius:9px;padding:9px 12px;background:color-mix(in srgb,var(--ch2) 4%,transparent)}
.ls-ask summary{cursor:pointer;display:flex;flex-direction:column;gap:3px;list-style:none}
.ls-ask summary::-webkit-details-marker{display:none}
.ls-q{font-weight:600;color:var(--ch2);font-size:14.5px}
.ls-reveal{font-size:12px;color:var(--muted)}
.ls-ask details[open] .ls-reveal{display:none}
.ls-ask details p{margin:8px 0 0;font-size:14.5px;line-height:1.55;color:var(--ink)}
.ls-nav{display:flex;gap:8px}
.ls-nav .btn{flex:1;padding:10px}
.btn:disabled{opacity:.35;cursor:default}
:lang(th) body,:lang(th) .ls-text p{line-height:1.7}
footer{border-top:1px solid var(--line);color:var(--dim);font-size:12.5px;padding-block:18px 28px;
  padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px));display:flex;flex-wrap:wrap;gap:6px 18px;justify-content:space-between;max-width:1500px;margin:0 auto}
.noscript{padding:24px;color:var(--warn)}

/* desktop: let the screens use the window height (phones keep the plain aspect ratios) */
@media (min-width:1181px) and (min-height:700px){
  .app{max-width:1840px}
  #screens > .screen .bezel{min-height:44vh}
  #screens .pair .bezel{min-height:36vh}
  #screens > div:not(.pair):not(.trio) > .screen .bezel{min-height:40vh}
  body.full #screens .bezel{min-height:0}
}
@media (max-width:1180px){
  .app{grid-template-columns:minmax(0,1fr)}
  nav#nav{position:static;flex-direction:row;overflow-x:auto;max-height:none;gap:6px;padding-bottom:4px;margin-inline:-4px;scrollbar-width:none}
  nav#nav::-webkit-scrollbar{display:none}
  .ng{flex-direction:row;gap:4px;align-items:center;flex:none}
  .ngt{display:none}
  .nl{white-space:nowrap;padding:6px 10px;border-color:var(--line)}
  .nl .lv{display:none}
}
@media (max-width:900px){
  .bench{grid-template-columns:minmax(0,1fr)}
  body.guided #panel{order:-1}
  .langs{margin-left:auto}
  .tag,.edition{display:none}
}
@media (max-width:640px){
  .pair,.trio{grid-template-columns:minmax(0,1fr)}
  #intro .sub{font-size:15px}
}
@media (prefers-reduced-motion: reduce){*{scroll-behavior:auto!important}}
/* a screen that keeps its aspect ratio on desktop too (e.g. a wide road strip) */
#screens .screen.short .bezel{min-height:0!important}
/* status tag next to the lab name: live, in progress or experimental */
.status{flex:none;font:600 10.5px var(--f-num);letter-spacing:.12em;text-transform:uppercase;color:var(--ch2);border:1px dashed color-mix(in srgb,var(--ch2) 60%,transparent);border-radius:999px;padding:2px 9px;white-space:nowrap}
@media (max-width:440px){.status{font-size:9.5px;padding:2px 6px}}