:root{
  --bg:#F2F5F9; --surface:#FFFFFF; --ink:#101B2D; --mut:#56637A; --line:#D5DCE7; --soft:#E8EEF5;
  --sig:#0B7A85; --noise:#B85F16; --edge:#C23B5A; --sigsoft:#DDF0F1; --plot:#0F1B2E;
  --code-bg:#0F1A2B; --code-fg:#DCE6F5; --focus:#0B7A85;
  color-scheme: light;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#0B121D; --surface:#121C2B; --ink:#E6ECF6; --mut:#95A3BA; --line:#25334A; --soft:#172336;
    --sig:#45C4CF; --noise:#F0A45C; --edge:#F2738F; --sigsoft:#12333A; --plot:#E6ECF6;
    --code-bg:#0A101A; --code-fg:#D5E0F1; --focus:#45C4CF; color-scheme: dark;
  }
}
:root[data-theme="dark"]{
  --bg:#0B121D; --surface:#121C2B; --ink:#E6ECF6; --mut:#95A3BA; --line:#25334A; --soft:#172336;
  --sig:#45C4CF; --noise:#F0A45C; --edge:#F2738F; --sigsoft:#12333A; --plot:#E6ECF6;
  --code-bg:#0A101A; --code-fg:#D5E0F1; --focus:#45C4CF; color-scheme: dark;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:64px}
body{background:var(--bg);color:var(--ink);font-family:"IBM Plex Sans Arabic",Tahoma,"Segoe UI",system-ui,sans-serif;font-size:16.5px;line-height:1.9;margin:0;padding-inline:16px}
.wrap{max-width:1120px;margin-inline:auto}
:focus-visible{outline:2px solid var(--focus);outline-offset:2px}
a{color:var(--sig)}
h1,h2,h3{line-height:1.45;text-wrap:balance;margin:0}
.ltr{direction:ltr;unicode-bidi:isolate;font-family:"IBM Plex Mono",ui-monospace,Consolas,monospace;font-size:.92em}
.mono{font-family:"IBM Plex Mono",ui-monospace,Consolas,monospace;font-variant-numeric:tabular-nums}

/* top bar */
.bar{position:sticky;top:env(safe-area-inset-top,0px);z-index:20;background:var(--bg);border-bottom:1px solid var(--line);margin-inline:-16px;padding-inline:16px}
.bar .wrap{display:flex;align-items:center;gap:18px;min-height:52px}
.bar b{font-weight:700;white-space:nowrap;font-size:15px}
.bar nav{display:flex;gap:4px;overflow-x:auto;scrollbar-width:none;flex:1}
.bar nav a{white-space:nowrap;text-decoration:none;color:var(--mut);padding:6px 11px;border-radius:6px;font-size:14px}
.bar nav a:hover{background:var(--soft);color:var(--ink)}

/* hero */
.hero{padding-block:44px 30px;display:grid;grid-template-columns:1.25fr 1fr;gap:36px;align-items:start}
.eyebrow{font-size:13px;letter-spacing:.06em;color:var(--sig);font-weight:600;margin-bottom:10px}
.hero h1{font-size:clamp(28px,4.2vw,44px);font-weight:700}
.hero p.lead{font-size:18px;color:var(--mut);margin:16px 0 0;max-width:60ch}
.hero p.me{font-size:19px;line-height:1.85;margin:0 0 22px;padding:14px 18px;background:var(--surface);border:1px solid var(--line);border-inline-start:3px solid var(--sig);border-radius:8px;max-width:62ch}
.hero p.me b{font-weight:700}
.who{margin-top:22px;display:flex;flex-wrap:wrap;gap:8px 22px;font-size:15px}
.who span{color:var(--mut)} .who b{font-weight:600}
.panel{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:18px 20px}
.panel h3{font-size:15px;margin-bottom:8px}
.panel ol,.panel ul{margin:0;padding-inline-start:20px;font-size:15px;line-height:1.85}
.panel li+li{margin-top:2px}
.honest{margin-top:14px;border-inline-start:3px solid var(--noise);border-radius:0 8px 8px 0}

/* sections */
section{padding-block:46px;border-top:1px solid var(--line)}
.tag{display:inline-block;font-size:12.5px;font-weight:600;color:var(--sig);background:var(--sigsoft);padding:2px 10px;border-radius:99px;margin-bottom:10px}
section>.wrap>h2{font-size:clamp(23px,3vw,31px);font-weight:700}
.intro{color:var(--mut);max-width:74ch;margin:10px 0 24px}
.lab{display:grid;grid-template-columns:minmax(230px,290px) minmax(0,1fr);gap:26px;align-items:start}
.ctl{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:16px 16px 6px;position:sticky;top:64px}
.ctl h3{font-size:14px;color:var(--mut);font-weight:600;margin-bottom:10px}
.row{margin-bottom:14px}
.row label{display:flex;justify-content:space-between;gap:8px;font-size:14px;margin-bottom:3px}
.row label output{color:var(--sig);font-weight:600}
select,input[type=range],input[type=file],button{font:inherit;color:inherit}
select{width:100%;padding:6px 8px;background:var(--bg);border:1px solid var(--line);border-radius:6px}
input[type=range]{width:100%;accent-color:var(--sig)}
input[type=file]{width:100%;font-size:13px}
.chk{display:flex;gap:8px;align-items:center;font-size:14px;margin-bottom:12px}
.btn{background:var(--sig);color:#fff;border:0;border-radius:6px;padding:7px 14px;cursor:pointer;font-weight:600;font-size:14px}
:root[data-theme="dark"] .btn{color:#06222A}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) .btn{color:#06222A}}
.btn.ghost,:root[data-theme="dark"] .btn.ghost,:root:not([data-theme="light"]) .btn.ghost{background:var(--soft);color:var(--ink);border:1px solid var(--line)}
.btns{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:14px}
.seg{display:flex;border:1px solid var(--line);border-radius:6px;overflow:hidden;margin-bottom:14px}
.seg button{flex:1;background:var(--bg);border:0;padding:6px 4px;cursor:pointer;font-size:14px}
.seg button[aria-pressed=true]{background:var(--sig);color:#fff;font-weight:600}
:root[data-theme="dark"] .seg button[aria-pressed=true]{color:#06222A}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) .seg button[aria-pressed=true]{color:#06222A}}

.out{display:grid;gap:18px;min-width:0}
.grid2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
.grid3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.grid4{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}
figure{margin:0;min-width:0}
figure canvas{display:block;width:100%;height:auto;background:var(--surface);border:1px solid var(--line);border-radius:6px}
figure canvas.px{image-rendering:pixelated;aspect-ratio:1/1}
figcaption{font-size:13.5px;color:var(--mut);margin-top:6px;line-height:1.6}
figcaption b{color:var(--ink);font-weight:600}
.chips{display:flex;gap:6px;flex-wrap:wrap;margin-top:6px}
.chip{font-size:12.5px;background:var(--soft);border-radius:5px;padding:1px 8px;font-family:"IBM Plex Mono",monospace;direction:ltr}
.chip.hi{background:var(--sigsoft);color:var(--sig);font-weight:500}
.note{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:14px 18px;font-size:15px;line-height:1.85}
.note b{font-weight:600}
.note.key{border-inline-start:3px solid var(--sig)}
.eq{direction:ltr;text-align:center;font-family:"IBM Plex Mono",monospace;font-size:15px;background:var(--soft);border-radius:8px;padding:10px 14px;margin:0;overflow-x:auto;white-space:nowrap}
.tw{overflow-x:auto}
table{border-collapse:collapse;width:100%;font-size:14.5px}
th,td{padding:7px 10px;border-bottom:1px solid var(--line);text-align:start;vertical-align:top}
th{font-weight:600;background:var(--soft);white-space:nowrap}
td.n,th.n{text-align:end;font-family:"IBM Plex Mono",monospace;direction:ltr;font-variant-numeric:tabular-nums}
tr.best td{background:var(--sigsoft)}
.legend{display:flex;gap:14px;flex-wrap:wrap;font-size:13px;color:var(--mut)}
.legend i{display:inline-block;width:10px;height:10px;border-radius:2px;margin-inline-end:5px;vertical-align:-1px}
pre{direction:ltr;text-align:left;background:var(--code-bg);color:var(--code-fg);padding:16px 18px;border-radius:8px;overflow-x:auto;font-size:13px;line-height:1.6;margin:0;font-family:"IBM Plex Mono",monospace}
details{background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:0 16px}
details+details{margin-top:8px}
summary{cursor:pointer;padding:12px 0;font-weight:600;list-style:none}
summary::-webkit-details-marker{display:none}
summary::before{content:"+";display:inline-block;width:20px;color:var(--sig);font-weight:700}
details[open] summary::before{content:"−"}
details p{margin:0 0 14px;color:var(--mut)}
ol.refs{direction:ltr;text-align:left;font-size:14px;line-height:1.7;padding-inline-start:36px;font-family:"IBM Plex Sans",system-ui,sans-serif}
ol.refs li{margin-bottom:6px;overflow-wrap:anywhere}
footer{padding-block:34px 60px;border-top:1px solid var(--line);color:var(--mut);font-size:14px}
@media (max-width:900px){
  .hero{grid-template-columns:1fr}
  .lab{grid-template-columns:1fr}
  .ctl{position:static}
  .grid4{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid3{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:560px){.grid2,.grid3{grid-template-columns:1fr}}
@media (prefers-reduced-motion: reduce){html{scroll-behavior:auto}}