/* ob-wheel.com — self-hosted styles, no external requests.
   Font strategy: Inter is used if the self-hosted woff2 is present (see /assets/fonts),
   otherwise the system-ui stack renders identically-weighted. No network font calls. */

/* @font-face is defined only if you drop Inter into /assets/fonts/.
   Left commented so there is zero risk of a failed external request out of the box.
   To enable: place Inter-var.woff2 in public/assets/fonts/ and uncomment.
@font-face{
  font-family:"Inter var";
  font-weight:100 900;
  font-display:swap;
  font-style:normal;
  src:url("/assets/fonts/Inter-var.woff2") format("woff2");
}
*/

/* ---------- Design tokens ---------- */
:root{
  --primary:#0F766E;
  --primary-strong:#115E59;
  --primary-tint:#F0FDFA;
  --accent:#F59E0B;
  --accent-strong:#B45309;
  --ink:#1F2937;
  --muted:#6B7280;
  --bg:#FFFFFF;
  --bg-alt:#F9FAFB;
  --border:#E5E7EB;
  --success:#16A34A;
  --warning:#D97706;
  --error:#DC2626;

  --surface:var(--bg);
  --surface-alt:var(--bg-alt);
  --shadow:0 1px 2px rgba(16,24,40,.04), 0 8px 24px -12px rgba(16,24,40,.18);
  --radius:14px;
  --radius-sm:10px;

  --font-sans:"Inter var","Inter",system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --font-serif:"Source Serif 4",Georgia,"Times New Roman",serif;
  --maxw:1080px;
  --measure:68ch;
}

@media (prefers-color-scheme: dark){
  :root{
    --primary:#2DD4BF;
    --primary-strong:#5EEAD4;
    --primary-tint:#0B2E2B;
    --accent:#FBBF24;
    --accent-strong:#FCD34D;
    --ink:#E5E7EB;
    --muted:#9CA3AF;
    --bg:#0B1220;
    --bg-alt:#111827;
    --border:#273244;
    --success:#4ADE80;
    --warning:#FBBF24;
    --error:#F87171;
    --shadow:0 1px 2px rgba(0,0,0,.3), 0 10px 30px -12px rgba(0,0,0,.6);
  }
}

/* ---------- Reset-ish ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--font-sans);
  font-size:clamp(16px,1rem + .1vw,17px);
  line-height:1.6;
  color:var(--ink);
  background:var(--bg);
  font-feature-settings:"cv05","ss01";
  text-rendering:optimizeLegibility;
  -webkit-font-smoothing:antialiased;
}
img,svg{max-width:100%;height:auto;display:block}
a{color:var(--primary);text-underline-offset:2px}
a:hover{color:var(--primary-strong)}
h1,h2,h3,h4{line-height:1.2;color:var(--ink);letter-spacing:-.01em}
h1{font-size:clamp(1.8rem,1.3rem + 2vw,2.6rem);margin:.2em 0 .3em}
h2{font-size:clamp(1.35rem,1.1rem + 1vw,1.75rem);margin:1.6em 0 .4em}
h3{font-size:1.15rem;margin:1.4em 0 .3em}
p{margin:0 0 1em}
:where(main) ul,:where(main) ol{margin:0 0 1em;padding-left:1.3em}
:where(main) li{margin:.25em 0}
code,kbd{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.92em}
hr{border:0;border-top:1px solid var(--border);margin:2rem 0}

/* ---------- Accessibility helpers ---------- */
.skip-link{
  position:absolute;left:-999px;top:0;z-index:100;
  background:var(--primary);color:#fff;padding:.6rem 1rem;border-radius:0 0 var(--radius-sm) 0;
}
.skip-link:focus{left:0}
:where(a,button,input,select,textarea,summary,[tabindex]):focus-visible{
  outline:3px solid var(--accent);
  outline-offset:2px;
  border-radius:6px;
}
.visually-hidden{
  position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}

/* ---------- Layout ---------- */
.container{width:min(100% - 2rem,var(--maxw));margin-inline:auto}
.site-header{
  position:sticky;top:0;z-index:20;
  background:color-mix(in srgb,var(--bg) 88%,transparent);
  backdrop-filter:saturate(1.4) blur(8px);
  border-bottom:1px solid var(--border);
}
.site-header .container{display:flex;align-items:center;gap:1rem;min-height:60px}
.brand{display:flex;align-items:center;gap:.55rem;font-weight:700;color:var(--ink);text-decoration:none;letter-spacing:-.02em}
.brand:hover{color:var(--primary-strong)}
.brand .mark{width:30px;height:30px;flex:0 0 auto}
.site-nav{margin-left:auto;display:flex;gap:.25rem;flex-wrap:wrap}
.site-nav a{
  color:var(--ink);text-decoration:none;padding:.5rem .7rem;border-radius:8px;font-weight:500;font-size:.96rem;
}
.site-nav a:hover{background:var(--primary-tint);color:var(--primary-strong)}
.site-nav a[aria-current="page"]{color:var(--primary-strong);background:var(--primary-tint)}

main{display:block}
.section{padding-block:clamp(2rem,1rem + 4vw,3.5rem)}

/* ---------- Buttons ---------- */
.btn{
  --_bg:var(--primary);--_fg:#fff;
  display:inline-flex;align-items:center;gap:.45rem;justify-content:center;
  min-height:44px;padding:.6rem 1.1rem;border-radius:var(--radius-sm);
  background:var(--_bg);color:var(--_fg);border:1px solid transparent;
  font:inherit;font-weight:600;cursor:pointer;text-decoration:none;line-height:1;
  transition:background .15s ease,transform .05s ease;
}
.btn:hover{background:var(--primary-strong);color:#fff}
.btn:active{transform:translateY(1px)}
.btn-secondary{--_bg:transparent;--_fg:var(--primary);border-color:var(--border)}
.btn-secondary:hover{background:var(--primary-tint);color:var(--primary-strong)}
.btn-accent{--_bg:var(--accent);--_fg:#3a2a06}
.btn-accent:hover{background:var(--accent-strong);color:#fff}
.btn-sm{min-height:38px;padding:.4rem .75rem;font-size:.9rem}

/* ---------- Hero ---------- */
.hero{
  background:
    radial-gradient(120% 120% at 100% 0%, var(--primary-tint) 0%, transparent 55%),
    var(--bg);
  border-bottom:1px solid var(--border);
}
.hero .container{padding-block:clamp(1.5rem,1rem + 3vw,2.5rem)}
.hero-grid{display:grid;gap:clamp(1.25rem,1rem + 2vw,2rem);grid-template-columns:1fr}
@media(min-width:900px){.hero-grid{grid-template-columns:1.05fr .95fr;align-items:start}}
.eyebrow{
  display:inline-flex;align-items:center;gap:.4rem;
  text-transform:uppercase;letter-spacing:.08em;font-size:.78rem;font-weight:700;
  color:var(--primary-strong);background:var(--primary-tint);
  padding:.3rem .6rem;border-radius:999px;border:1px solid color-mix(in srgb,var(--primary) 22%,transparent);
}
.hero h1{margin-top:.7rem;max-width:16ch}
.lede{font-size:1.06rem;color:var(--muted);max-width:52ch}
.hero-points{list-style:none;padding:0;margin:1rem 0 0;display:grid;gap:.4rem}
.hero-points li{display:flex;gap:.55rem;align-items:flex-start;color:var(--ink);font-size:.96rem}
.hero-points svg{flex:0 0 auto;margin-top:.15rem;color:var(--primary)}

/* ---------- Calculator card ---------- */
.calc{
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  box-shadow:var(--shadow);overflow:hidden;
}
.calc__head{padding:1rem 1.1rem .25rem}
.calc__title{font-size:1.05rem;margin:0}
.modes{
  display:flex;flex-wrap:wrap;gap:.35rem;padding:.75rem 1.1rem 0;
}
.mode-tab{
  appearance:none;border:1px solid var(--border);background:var(--bg-alt);color:var(--ink);
  padding:.5rem .8rem;border-radius:999px;font:inherit;font-size:.9rem;font-weight:600;cursor:pointer;min-height:40px;
}
.mode-tab[aria-selected="true"]{background:var(--primary);border-color:var(--primary);color:#fff}
.mode-tab:hover:not([aria-selected="true"]){background:var(--primary-tint);color:var(--primary-strong)}

.calc__body{padding:1rem 1.1rem 1.25rem}
.field-grid{display:grid;grid-template-columns:1fr;gap:.9rem}
@media(min-width:520px){.field-grid{grid-template-columns:1fr 1fr}}
.field{display:flex;flex-direction:column;gap:.3rem}
.field--full{grid-column:1/-1}
.field label{font-weight:600;font-size:.92rem}
.field .hint{font-size:.82rem;color:var(--muted)}
.field input,.field select{
  font:inherit;min-height:44px;padding:.55rem .7rem;border:1px solid var(--border);
  border-radius:var(--radius-sm);background:var(--bg);color:var(--ink);width:100%;
}
.field input:focus,.field select:focus{border-color:var(--primary)}
.field input[aria-invalid="true"]{border-color:var(--error)}
.wd-pair{display:flex;gap:.5rem}
.wd-pair .field{flex:1}
.field-error{color:var(--error);font-size:.84rem;min-height:1.1em;font-weight:600}
.field-error:empty{min-height:0}

.calc__actions{display:flex;flex-wrap:wrap;gap:.5rem;margin-top:1rem}

/* ---------- Results ---------- */
.results{
  margin-top:1.1rem;border-top:1px solid var(--border);padding-top:1.1rem;
  font-variant-numeric:tabular-nums;
}
.result-primary{display:grid;gap:.15rem;margin-bottom:.9rem}
.result-primary .label{font-size:.8rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);font-weight:700}
.result-primary .edd{font-size:clamp(1.5rem,1.2rem + 1.6vw,2rem);font-weight:800;letter-spacing:-.02em}
.result-grid{display:grid;gap:.6rem;grid-template-columns:repeat(2,1fr)}
@media(min-width:520px){.result-grid{grid-template-columns:repeat(4,1fr)}}
.stat{background:var(--bg-alt);border:1px solid var(--border);border-radius:var(--radius-sm);padding:.7rem}
.stat .k{font-size:.76rem;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);font-weight:700}
.stat .v{font-size:1.15rem;font-weight:700;margin-top:.15rem}
.method-line{margin:.9rem 0 0;font-size:.9rem;color:var(--muted)}
.method-line a{font-weight:600}

.trimester-chip{display:inline-block;padding:.15rem .5rem;border-radius:999px;font-size:.8rem;font-weight:700;border:1px solid var(--border)}
.trimester-chip[data-t="1"]{background:var(--primary-tint);color:var(--primary-strong);border-color:color-mix(in srgb,var(--primary) 25%,transparent)}
.trimester-chip[data-t="2"]{background:#FEF3C7;color:#92400E;border-color:#FDE68A}
.trimester-chip[data-t="3"]{background:#EDE9FE;color:#5B21B6;border-color:#DDD6FE}
@media (prefers-color-scheme:dark){
  .trimester-chip[data-t="2"]{background:#3a2e0a;color:#FCD34D;border-color:#5b4708}
  .trimester-chip[data-t="3"]{background:#241a4a;color:#C4B5FD;border-color:#3a2c66}
}

/* Milestones table */
.milestones{margin-top:1.1rem}
.milestones h3{margin:.2rem 0 .5rem;font-size:1rem}
table.msto{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums;font-size:.94rem}
table.msto caption{text-align:left;color:var(--muted);font-size:.85rem;margin-bottom:.4rem}
table.msto th,table.msto td{text-align:left;padding:.5rem .5rem;border-bottom:1px solid var(--border)}
table.msto th{font-weight:700;color:var(--muted);font-size:.8rem;text-transform:uppercase;letter-spacing:.04em}
table.msto td:last-child{text-align:right;font-weight:700}

/* Callout / disclaimer */
.note{
  display:flex;gap:.6rem;align-items:flex-start;margin-top:1rem;
  background:var(--primary-tint);border:1px solid color-mix(in srgb,var(--primary) 18%,transparent);
  border-radius:var(--radius-sm);padding:.75rem .85rem;font-size:.9rem;color:var(--ink);
}
.note svg{flex:0 0 auto;color:var(--primary);margin-top:.1rem}
.disclaimer{
  background:var(--bg-alt);border:1px solid var(--border);border-left:4px solid var(--accent);
  border-radius:var(--radius-sm);padding:.85rem 1rem;font-size:.9rem;color:var(--muted);margin:1.25rem 0;
}
.disclaimer strong{color:var(--ink)}

.reveal-status{font-size:.9rem;font-weight:600}
.reveal-status[data-ok="true"]{color:var(--success)}

/* ---------- Cards / article index ---------- */
.grid-cards{display:grid;gap:1rem;grid-template-columns:1fr}
@media(min-width:640px){.grid-cards{grid-template-columns:1fr 1fr}}
@media(min-width:960px){.grid-cards{grid-template-columns:1fr 1fr 1fr}}
.card{
  display:flex;flex-direction:column;gap:.4rem;background:var(--surface);
  border:1px solid var(--border);border-radius:var(--radius);padding:1.1rem;box-shadow:var(--shadow);
}
.card h3{margin:0;font-size:1.08rem}
.card h3 a{text-decoration:none;color:var(--ink)}
.card h3 a:hover{color:var(--primary-strong)}
.card p{margin:0;color:var(--muted);font-size:.94rem}
.card .kw{margin-top:auto;font-size:.78rem;color:var(--primary-strong);font-weight:600}

/* ---------- Article typography ---------- */
.article{max-width:var(--measure);margin-inline:auto}
.article .meta{color:var(--muted);font-size:.9rem;margin-bottom:1rem}
.article h2{border-top:1px solid var(--border);padding-top:1.2rem}
.article h2:first-of-type{border-top:0;padding-top:0}
.breadcrumbs{font-size:.86rem;color:var(--muted);margin:0 0 1rem;display:flex;gap:.4rem;flex-wrap:wrap}
.breadcrumbs a{text-decoration:none}
.breadcrumbs li{list-style:none}
.breadcrumbs ol{display:flex;gap:.4rem;flex-wrap:wrap;padding:0;margin:0}
.breadcrumbs li:not(:last-child)::after{content:"›";margin-left:.4rem;color:var(--muted)}

.faq details{border:1px solid var(--border);border-radius:var(--radius-sm);padding:.25rem .9rem;margin:.5rem 0;background:var(--surface)}
.faq summary{cursor:pointer;font-weight:600;padding:.6rem 0;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"＋";color:var(--primary);margin-right:.5rem;font-weight:700}
.faq details[open] summary::before{content:"－"}
.faq details[open] summary{border-bottom:1px solid var(--border)}
.faq p{padding-top:.6rem}

.related{margin-top:2rem;background:var(--bg-alt);border:1px solid var(--border);border-radius:var(--radius);padding:1.1rem}
.related h2{border:0;padding:0;margin:0 0 .6rem;font-size:1.1rem}
.related ul{margin:0;padding-left:1.1rem}

.sources{font-size:.9rem}
.sources ol{padding-left:1.2rem}

/* ---------- Footer ---------- */
.site-footer{border-top:1px solid var(--border);background:var(--bg-alt);margin-top:2.5rem}
.site-footer .container{padding-block:2rem;display:grid;gap:1.25rem;grid-template-columns:1fr}
@media(min-width:720px){.site-footer .container{grid-template-columns:1.4fr 1fr 1fr}}
.site-footer h4{margin:0 0 .5rem;font-size:.82rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
.site-footer ul{list-style:none;padding:0;margin:0;display:grid;gap:.35rem}
.site-footer a{color:var(--ink);text-decoration:none;font-size:.94rem}
.site-footer a:hover{color:var(--primary-strong)}
.foot-legal{grid-column:1/-1;border-top:1px solid var(--border);padding-top:1rem;color:var(--muted);font-size:.82rem}

/* ---------- 404 ---------- */
.center-narrow{max-width:44ch;margin-inline:auto;text-align:center}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  *{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important;scroll-behavior:auto!important}
}

/* ---------- Print ---------- */
@media print{
  .site-header,.site-footer,.calc__actions,.modes,.site-nav,.skip-link,.hero-points,.note{display:none!important}
  body{background:#fff;color:#000;font-size:12pt}
  .calc{border:0;box-shadow:none}
  .hero{background:#fff;border:0}
  .results{border-top:2px solid #000}
  a[href]::after{content:"";}
  .stat,.disclaimer{border:1px solid #999}
  @page{margin:1.6cm}
}