.rl-helmets{--rlh-ink:#18232D;--rlh-ink2:#45525E;--rlh-slate:#EDF2F6;--rlh-blue:#135DFF;--rlh-cyan:#00A8BD;--rlh-white:#FFFFFF;--rlh-rule:rgba(24,35,45,.16);--rlh-rule2:rgba(24,35,45,.34);
  max-width:1120px;margin-inline:auto;padding-inline:clamp(16px,4vw,32px);direction:rtl;color:var(--rlh-ink);background:var(--rlh-white);font:400 1rem/1.6 "Heebo","IBM Plex Sans",system-ui,sans-serif;overflow-wrap:break-word}
.rl-helmets *,.rl-helmets *::before,.rl-helmets *::after{box-sizing:border-box}
.rl-helmets [hidden]{display:none!important}
.rl-helmets a{color:var(--rlh-blue);text-underline-offset:.2em;text-decoration-thickness:1px}
.rl-helmets a:hover{color:var(--rlh-ink)}
.rl-helmets :focus-visible{outline:3px solid var(--rlh-blue);outline-offset:2px}
.rlh-num{font-family:"IBM Plex Mono",ui-monospace,Menlo,monospace;font-variant-numeric:tabular-nums;direction:ltr;unicode-bidi:isolate}
.rlh-lat{font-family:"IBM Plex Sans","Heebo",system-ui,sans-serif}
.rlh-sr{position:absolute!important;width:1px;height:1px;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;padding:0}

/* hero */
.rlh-hero{display:grid;grid-template-columns:minmax(0,1fr);grid-template-areas:"intro" "tool" "fig";gap:16px;padding-block:clamp(16px,3vw,32px)}
.rlh-intro{grid-area:intro;border-top:4px solid var(--rlh-ink);padding-top:14px}
.rlh-kicker{display:flex;align-items:center;gap:10px;margin:0;color:var(--rlh-blue);font-weight:700;font-size:.9375rem}
.rlh-kicker::before{content:"";inline-size:24px;block-size:2px;background:var(--rlh-cyan)}
.rlh-h2{margin:6px 0 0;font-weight:800;font-size:clamp(1.75rem,1.1rem + 3vw,3.25rem);line-height:1.08;letter-spacing:-.01em;text-wrap:balance}
.rlh-lead{margin:10px 0 0;max-width:46ch;font-size:clamp(1rem,.95rem + .3vw,1.1875rem);color:var(--rlh-ink2);text-wrap:pretty}
.rlh-tool{grid-area:tool;min-width:0;display:grid;gap:14px;background:var(--rlh-slate);padding:16px clamp(14px,3vw,24px) 20px;border-top:4px solid var(--rlh-blue)}
.rlh-fig{grid-area:fig;margin:0;min-width:0}
.rlh-fig__frame{aspect-ratio:4/3;background:var(--rlh-white);border:1px solid var(--rlh-rule2);display:grid;place-items:center;padding:12px;overflow:hidden}
.rlh-fig__frame img{display:block;max-width:100%;max-height:100%;width:auto;height:auto;object-fit:contain}
.rlh-fig__cap{padding-top:8px;font-size:.875rem;font-weight:600;color:var(--rlh-ink2);border-bottom:1px solid var(--rlh-rule);padding-bottom:8px}
@media (min-width:900px){
  .rlh-hero{grid-template-columns:minmax(0,1.3fr) minmax(0,1fr);grid-template-areas:"intro fig" "tool fig";column-gap:40px;align-items:start}
  .rlh-fig{position:sticky;top:24px}
  .rlh-fig__frame{aspect-ratio:1/1}
}

/* form */
.rlh-form{display:grid;grid-template-columns:minmax(0,1fr);gap:12px}
.rlh-field{display:grid;gap:6px;min-width:0}
.rlh-label{font-weight:700;font-size:.9375rem}
.rlh-hint{margin:0;font-size:.8125rem;color:var(--rlh-ink2)}
.rlh-input,.rlh-select{inline-size:100%;min-width:0;min-height:48px;padding:0 12px;border:1.5px solid var(--rlh-ink);border-radius:2px;background:var(--rlh-white);color:var(--rlh-ink)}
.rlh-input{font-size:1.25rem;font-weight:600;text-align:right}
.rlh-select{font:500 1rem/1.2 "IBM Plex Sans","Heebo",system-ui,sans-serif}
.rlh-input[aria-invalid="true"]{border-width:3px}
.rlh-err{margin:0;padding:8px 10px;border:2px solid var(--rlh-ink);background:var(--rlh-white);font-weight:700;font-size:.9375rem}
.rlh-btn{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:0 18px;border:1.5px solid var(--rlh-ink);border-radius:2px;background:var(--rlh-white);color:var(--rlh-ink)!important;font:700 1rem/1.2 "Heebo",system-ui,sans-serif;text-decoration:none;cursor:pointer}
.rlh-btn:hover{background:var(--rlh-ink);color:var(--rlh-white)!important}
.rlh-btn--primary{background:var(--rlh-blue);border-color:var(--rlh-blue);color:var(--rlh-white)!important}
.rlh-btn--primary:hover{background:var(--rlh-ink);border-color:var(--rlh-ink)}
@media (min-width:560px){.rlh-form{grid-template-columns:repeat(2,minmax(0,1fr));align-items:start}.rlh-form__go{grid-column:1 / -1}}

/* measuring tape */
.rlh-tape{direction:ltr;position:relative;padding:6px 0 2px;min-width:0}
.rlh-tape__scale{block-size:14px;background:
  repeating-linear-gradient(to right,var(--rlh-ink) 0 1.5px,transparent 1.5px 20%) 0 0/100% 14px no-repeat,
  repeating-linear-gradient(to right,var(--rlh-ink2) 0 1px,transparent 1px 4%) 0 6px/100% 8px no-repeat,
  var(--rlh-white);border-bottom:1.5px solid var(--rlh-ink)}
.rlh-tape__nums{position:relative;block-size:18px;font:500 .6875rem/18px "IBM Plex Mono",ui-monospace,monospace;color:var(--rlh-ink2)}
.rlh-tape__nums span{position:absolute;left:var(--p);transform:translateX(-50%)}
.rlh-tape__nums span:first-child{transform:none}
.rlh-tape__nums span:last-child{transform:translateX(-100%)}
.rlh-tape__bands{display:grid;gap:3px;margin-top:4px}
.rlh-band{position:relative;block-size:20px;background:var(--rlh-white)}
.rlh-band__bar{position:absolute;inset-block:0;left:var(--a);width:var(--w);display:grid;place-items:center;font:600 .75rem/1 "IBM Plex Mono",ui-monospace,monospace;color:var(--rlh-white);background:var(--rlh-ink)}
.rlh-band__bar[data-size="M"]{background:var(--rlh-blue)}
.rlh-band__bar[data-size="L"]{background:var(--rlh-cyan);color:var(--rlh-ink)}
.rlh-tape__marker{position:absolute;top:0;bottom:0;left:var(--v);inline-size:0;border-left:2px solid var(--rlh-ink);pointer-events:none}
.rlh-tape__marker span{position:absolute;top:-2px;left:4px;padding:0 4px;background:var(--rlh-ink);color:var(--rlh-white);font:600 .6875rem/16px "IBM Plex Mono",ui-monospace,monospace}

/* result */
.rlh-res{background:var(--rlh-white);border:1.5px solid var(--rlh-ink);padding:14px}
.rlh-res p{margin:0}
.rlh-res__idle{color:var(--rlh-ink2);font-size:.9375rem}
.rlh-res__k{font-weight:700;font-size:.9375rem}
.rlh-res__list{list-style:none;margin:10px 0 0;padding:0;display:grid;gap:0}
.rlh-res__item{display:grid;grid-template-columns:auto minmax(0,1fr);align-items:center;gap:14px;padding:10px 0;border-top:1px solid var(--rlh-rule)}
.rlh-res__size{display:grid;place-items:center;inline-size:52px;block-size:52px;background:var(--rlh-blue);color:var(--rlh-white);font-size:1.5rem;font-weight:600}
.rlh-res__d{display:grid;gap:2px;font-size:.9375rem}
.rlh-res__d span:first-child{font-weight:700}
.rlh-res__note{margin-top:8px!important;padding:8px 10px;background:var(--rlh-slate);font-size:.875rem;font-weight:600}
.rlh-res__ctx{margin-top:10px!important;font-size:.8125rem;color:var(--rlh-ink2)}
.rlh-res__warn{font-weight:700}

/* self-check */
.rlh-check{margin:0;padding:0;border:0;min-width:0;display:grid;gap:6px}
.rlh-check__lg{padding:0;margin-bottom:6px;font-weight:800;font-size:1.0625rem}
.rlh-step{display:grid;grid-template-columns:32px minmax(0,1fr) 44px;align-items:center;gap:10px;min-height:56px;padding:8px 10px;background:var(--rlh-white);border:1.5px solid var(--rlh-rule2);border-radius:2px;cursor:pointer}
.rlh-step:hover{border-color:var(--rlh-ink)}
.rlh-step:has(input:checked){border-color:var(--rlh-ink);box-shadow:inset 0 3px 0 var(--rlh-cyan)}
.rlh-step:has(input:focus-visible){outline:3px solid var(--rlh-blue);outline-offset:2px}
.rlh-step__n{display:grid;place-items:center;inline-size:32px;block-size:32px;background:var(--rlh-ink);color:var(--rlh-white);font-weight:600}
.rlh-step__t{display:grid;gap:1px;min-width:0}
.rlh-step__t strong{font-weight:700}
.rlh-step__t span{font-size:.8125rem;color:var(--rlh-ink2)}
.rlh-step input{inline-size:26px;block-size:26px;margin:0;justify-self:center;accent-color:var(--rlh-blue);cursor:pointer}
.rlh-check:disabled .rlh-step{opacity:.55;cursor:not-allowed}
.rlh-check__sum{margin:4px 0 0;font-weight:600;font-size:.9375rem}
.rlh-share{display:grid;gap:8px}
.rlh-share__row{display:flex;flex-wrap:wrap;gap:8px}
.rlh-share__msg{margin:0;font-size:.875rem;font-weight:600}
.rlh-share__fb{inline-size:100%;min-width:0;padding:10px;border:1.5px solid var(--rlh-ink);border-radius:2px;background:var(--rlh-white);color:var(--rlh-ink);font:400 .9375rem/1.5 "Heebo",system-ui,sans-serif;resize:vertical}

/* sections */
.rlh-band-sec{margin-top:clamp(32px,5vw,56px);border-top:4px solid var(--rlh-ink);padding-top:16px}
.rlh-h3{margin:0;font-weight:800;font-size:clamp(1.375rem,1.1rem + 1.2vw,2rem);line-height:1.15}
.rlh-h4{margin:24px 0 8px;font-weight:700;font-size:1.0625rem}
.rlh-sub{margin:6px 0 12px;font-size:.9375rem;color:var(--rlh-ink2);max-width:70ch}
.rlh-tablewrap{max-inline-size:100%;overflow-x:auto;border-block:1.5px solid var(--rlh-ink)}
.rlh-table{inline-size:100%;min-inline-size:280px;border-collapse:collapse;font-size:.9375rem}
.rlh-table th,.rlh-table td{padding:10px 12px;text-align:start;border-top:1px solid var(--rlh-rule);vertical-align:middle}
.rlh-table thead th{border-top:0;background:var(--rlh-slate);font-size:.8125rem;font-weight:700}
.rlh-table tbody th[scope="row"]{font-weight:600}
.rlh-table__grp th{background:var(--rlh-white);font-weight:800;font-size:1rem;border-top:1.5px solid var(--rlh-ink);padding-top:14px}
.rlh-table td.rlh-num{font-weight:600}
.rlh-table tr.is-match th,.rlh-table tr.is-match td{background:rgba(19,93,255,.08)}
.rlh-table tr.is-match th[scope="row"]{box-shadow:inset -4px 0 0 var(--rlh-blue)}
.rlh-table--spec td,.rlh-table--spec th{inline-size:33%}

/* cross-section */
.rlh-x__grid{display:grid;grid-template-columns:minmax(0,1fr);gap:20px;margin-top:14px}
.rlh-x__fig{margin:0;min-width:0}
.rlh-x__art{background:var(--rlh-white);border:1px solid var(--rlh-rule2);padding:12px}
.rlh-x__art svg{display:block;inline-size:100%;block-size:auto;aspect-ratio:400/340;max-inline-size:520px;margin-inline:auto}
.rlh-x__cap{padding-top:8px;font-size:.875rem;font-weight:600;color:var(--rlh-ink2)}
.rlh-x__list{list-style:none;margin:0;padding:0;display:grid;align-content:start}
.rlh-x__list li{display:grid;grid-template-columns:32px minmax(0,1fr);gap:12px;padding:12px 0;border-top:1px solid var(--rlh-rule)}
.rlh-x__list li:first-child{border-top:0;padding-top:0}
.rlh-x__n{display:grid;place-items:center;inline-size:28px;block-size:28px;background:var(--rlh-blue);color:var(--rlh-white);font-weight:600;font-size:.875rem}
.rlh-x__list strong{font-weight:700}
.rlh-x__list p{margin:2px 0 0;font-size:.9375rem;color:var(--rlh-ink2)}
@media (min-width:860px){.rlh-x__grid{grid-template-columns:minmax(0,1.1fr) minmax(0,1fr);column-gap:40px;align-items:start}}

/* chapter nav */
.rlh-toc{margin-top:clamp(32px,5vw,56px);background:var(--rlh-ink);padding:6px clamp(12px,3vw,20px)}
.rlh-toc__list{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 16px}
.rlh-toc a{display:flex;align-items:center;gap:10px;min-height:48px;color:var(--rlh-white);font-weight:600;text-decoration:none}
.rlh-toc a:hover{color:var(--rlh-cyan)}
.rlh-toc a .rlh-num{color:var(--rlh-cyan);font-size:.8125rem}
.rl-helmets .rlh-toc a:focus-visible{outline-color:var(--rlh-cyan)}
@media (min-width:860px){.rlh-toc__list{grid-template-columns:repeat(4,minmax(0,1fr))}}
.rlh-ch{scroll-margin-top:24px;margin-top:clamp(32px,5vw,56px)}
.rlh-ch__h{margin:0;font-weight:800;font-size:clamp(1.5rem,1.2rem + 1.4vw,2.25rem);line-height:1.15}

@media (forced-colors:active){
  .rlh-band__bar,.rlh-res__size,.rlh-step__n,.rlh-x__n{forced-color-adjust:none;background:CanvasText;color:Canvas}
  .rlh-table tr.is-match th,.rlh-table tr.is-match td{outline:2px solid Highlight}
}
@media print{.rlh-share,.rlh-tape{display:none!important}}

.rl-helmets .rlh-article{--rlh-sticky:96px;counter-reset:rlh-sec;margin-top:clamp(32px,5vw,56px);color:#18232D;font-family:"Heebo","IBM Plex Sans",system-ui,sans-serif}
.rl-helmets .rlh-article>section{counter-increment:rlh-sec;max-inline-size:65ch;margin-inline-start:0;margin-inline-end:auto;padding-block:clamp(28px,4vw,44px) 0;border-top:1px solid rgba(24,35,45,.16);scroll-margin-top:calc(var(--rlh-sticky) + 16px)}
.rl-helmets .rlh-article>section:first-child{border-top:4px solid #18232D}
.rl-helmets .rlh-article>section:target{border-top-color:#135DFF;box-shadow:0 -4px 0 #135DFF}
.rl-helmets .rlh-article h2{display:grid;grid-template-columns:auto minmax(0,1fr);align-items:baseline;column-gap:12px;margin:0 0 .9em;font-weight:800;font-size:clamp(1.375rem,1.1rem + 1.1vw,1.875rem);line-height:1.2;letter-spacing:-.005em;text-wrap:balance;scroll-margin-top:calc(var(--rlh-sticky) + 16px)}
.rl-helmets .rlh-article h2::before{content:counter(rlh-sec,decimal-leading-zero);font:600 .8125rem/1 "IBM Plex Mono",ui-monospace,Menlo,monospace;color:#135DFF;direction:ltr;unicode-bidi:isolate;padding-block:4px;border-top:2px solid #00A8BD;font-variant-numeric:tabular-nums}
.rl-helmets .rlh-article p{margin:0 0 1.15em;font-size:clamp(1.0625rem,1rem + .2vw,1.125rem);line-height:1.85;text-wrap:pretty;hyphens:manual;overflow-wrap:break-word}
.rl-helmets .rlh-article p:last-child{margin-bottom:0}
.rl-helmets .rlh-article h2+p{font-size:clamp(1.125rem,1.05rem + .3vw,1.25rem);line-height:1.75}
.rl-helmets .rlh-article strong{font-weight:700}
.rl-helmets .rlh-article a{color:#135DFF;text-decoration:underline;text-underline-offset:.2em;text-decoration-thickness:1px}
.rl-helmets .rlh-article a:hover{color:#18232D;text-decoration-thickness:2px}
.rl-helmets .rlh-article a:focus-visible{outline:3px solid #135DFF;outline-offset:2px;border-radius:1px}
.rl-helmets .rlh-article bdi,.rl-helmets .rlh-article [lang="en"]{font-family:"IBM Plex Sans","Heebo",system-ui,sans-serif}
.rl-helmets .rlh-article .rlh-num,.rl-helmets .rlh-article code{font-family:"IBM Plex Mono",ui-monospace,Menlo,monospace;font-size:.92em;font-variant-numeric:tabular-nums;direction:ltr;unicode-bidi:isolate}
.rl-helmets .rlh-article ul,.rl-helmets .rlh-article ol{margin:0 0 1.15em;padding-inline-start:1.25em;font-size:clamp(1.0625rem,1rem + .2vw,1.125rem);line-height:1.8}
.rl-helmets .rlh-article li+li{margin-top:.35em}
.rl-helmets .rlh-article li::marker{color:#135DFF;font-family:"IBM Plex Mono",ui-monospace,monospace}
.rl-helmets .rlh-ch{scroll-margin-top:calc(var(--rlh-sticky,96px) + 16px)}
@media (min-width:1000px){.rl-helmets .rlh-article>section{margin-inline-start:clamp(0px,6vw,96px)}}
@media (max-width:359px){
  .rl-helmets .rlh-article h2{column-gap:8px;font-size:1.3125rem}
  .rl-helmets .rlh-article p{font-size:1.0313rem;line-height:1.8}
}
@media print{
  .rl-helmets .rlh-article>section{max-inline-size:none;break-inside:auto;border-top-color:#000}
  .rl-helmets .rlh-article h2{break-after:avoid}
  .rl-helmets .rlh-article p{font-size:11.5pt;line-height:1.6;orphans:3;widows:3}
}

/* Keep the complete photograph inside its reserved mobile frame. */
.rlh-fig__frame{grid-template-columns:minmax(0,1fr);grid-template-rows:minmax(0,1fr)}
.rlh-fig__frame img{width:100%;height:100%;min-width:0;min-height:0;object-fit:contain}
.rlh-res__k .rlh-lat{white-space:nowrap}