/* Mathmatives shared stylesheet.
   Design tokens and a utility-first layout: simple, readable, fast.
   No webfonts (Core Web Vitals). */

:root{
  --ink:#22313F;
  --ink-soft:#52606D;
  --link:#0B5FA5;
  --link-hover:#084A82;
  --band:#14415F;
  --band-ink:#FFFFFF;
  --bg:#FFFFFF;
  --bg-alt:#F4F7FA;
  --border:#D6DEE6;
  --result:#0E7B4B;
  --result-bg:#EEF7F1;
  --warn:#9C4221;
  --warn-bg:#FBF1EA;
  --focus:#7FB3E8;
  --radius:6px;
  --maxw:1000px;
  --font:system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--font);
  font-size:1.0625rem;
  line-height:1.6;
  color:var(--ink);
  background:var(--bg);
}
img,svg{max-width:100%;height:auto}

a{color:var(--link);text-decoration:none}
a:hover,a:focus{color:var(--link-hover);text-decoration:underline}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px;border-radius:2px}

h1,h2,h3{line-height:1.25;color:var(--ink)}
h1{font-size:1.75rem;margin:.25rem 0 .75rem}
h2{font-size:1.35rem;margin:2.25rem 0 .6rem;padding-bottom:.3rem;border-bottom:1px solid var(--border)}
h3{font-size:1.1rem;margin:1.4rem 0 .4rem}
p{margin:.7rem 0}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 1rem}
main{padding-bottom:2.5rem}

/* Skip link */
.skip-link{position:absolute;left:-9999px;top:0;background:#fff;color:var(--ink);padding:.6rem 1rem;z-index:100}
.skip-link:focus{left:0}

/* ---------- Header ---------- */
.site-header{background:var(--band);color:var(--band-ink)}
.site-header .wrap{display:flex;flex-wrap:wrap;align-items:center;gap:.75rem 1.25rem;padding-top:.7rem;padding-bottom:.7rem}
.brand{font-size:1.3rem;font-weight:700;color:#fff;letter-spacing:.2px;white-space:nowrap}
.brand:hover,.brand:focus{color:#fff}
.brand .brand-mark{color:#8FD0A9}
.site-search{flex:1 1 260px;display:flex;position:relative;min-width:220px}
.site-search input{
  flex:1;border:1px solid #0E344C;border-radius:var(--radius) 0 0 var(--radius);
  padding:.5rem .75rem;font-size:1rem;font-family:inherit;color:var(--ink)
}
.site-search button{
  border:0;background:#0B5FA5;color:#fff;font-family:inherit;font-size:1rem;
  padding:.5rem .9rem;border-radius:0 var(--radius) var(--radius) 0;cursor:pointer
}
.site-search button:hover{background:#0d6cbb}
.search-suggest{
  position:absolute;top:calc(100% + 4px);left:0;right:0;background:#fff;border:1px solid var(--border);
  border-radius:var(--radius);box-shadow:0 4px 14px rgba(20,65,95,.18);list-style:none;margin:0;padding:.25rem;
  z-index:50;max-height:320px;overflow:auto
}
.search-suggest[hidden]{display:none}
.search-suggest li a{display:block;padding:.45rem .6rem;border-radius:4px;color:var(--ink)}
.search-suggest li a:hover,.search-suggest li a:focus,.search-suggest li a.is-active{background:var(--bg-alt);text-decoration:none}
.search-suggest .suggest-cat{color:var(--ink-soft);font-size:.85rem;margin-left:.35rem}

.site-nav{background:var(--bg-alt);border-bottom:1px solid var(--border)}
.site-nav ul{
  display:flex;gap:.25rem;list-style:none;margin:0 auto;max-width:var(--maxw);
  padding:.25rem 1rem;overflow-x:auto;-webkit-overflow-scrolling:touch
}
.site-nav a{display:block;padding:.5rem .7rem;white-space:nowrap;border-radius:4px;font-size:.97rem}
.site-nav a:hover,.site-nav a:focus{background:#E3ECF3;text-decoration:none}
.site-nav a[aria-current="page"]{font-weight:700;color:var(--ink)}

/* ---------- Breadcrumbs ---------- */
.breadcrumbs{font-size:.9rem;color:var(--ink-soft);margin:1rem 0 .25rem}
.breadcrumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:.25rem;margin:0;padding:0}
.breadcrumbs li+li::before{content:"›";margin:0 .35rem;color:var(--ink-soft)}

/* ---------- Calculator card ---------- */
.calc-card{
  border:1px solid var(--border);border-radius:var(--radius);background:var(--bg-alt);
  padding:1.1rem 1.1rem 1.25rem;margin:1rem 0 1.5rem
}
.calc-grid{display:grid;grid-template-columns:1fr 1fr;gap:.9rem 1.25rem}
.field{display:flex;flex-direction:column}
.field-wide{grid-column:1 / -1}
.field label{font-weight:600;font-size:.95rem;margin-bottom:.3rem}
.field .hint{font-weight:400;color:var(--ink-soft);font-size:.85rem}
.control{display:flex;align-items:stretch}
.field input,.field select{
  width:100%;font:inherit;color:var(--ink);background:#fff;
  border:1px solid #B7C4CF;border-radius:4px;padding:.5rem .6rem;min-height:44px
}
.field input:focus,.field select:focus{border-color:var(--link);outline:3px solid var(--focus);outline-offset:0}
.control .unit{
  display:flex;align-items:center;padding:0 .6rem;border:1px solid #B7C4CF;border-left:0;
  border-radius:0 4px 4px 0;background:#EDF2F6;color:var(--ink-soft);font-size:.92rem;white-space:nowrap
}
.control input{border-radius:4px 0 0 4px}
.control input:only-child{border-radius:4px}
fieldset.field{border:0;padding:0;margin:0}
fieldset.field legend{font-weight:600;font-size:.95rem;margin-bottom:.3rem;padding:0}
.radio-row{display:flex;gap:1rem;flex-wrap:wrap}
.radio-row label{font-weight:400;display:flex;align-items:center;gap:.4rem;min-height:44px;cursor:pointer}
/* Radios must not inherit the full-width, 44px text-input sizing above */
.radio-row input[type="radio"]{width:1.15rem;height:1.15rem;min-height:0;margin:0;padding:0;flex:0 0 auto;accent-color:var(--link);cursor:pointer}
.radio-row input[type="radio"]:focus{outline:3px solid var(--focus);outline-offset:2px}

.calc-actions{margin-top:1.1rem;display:flex;gap:.75rem;flex-wrap:wrap}
.btn{
  font:inherit;font-weight:600;cursor:pointer;border-radius:var(--radius);
  padding:.6rem 1.4rem;min-height:44px;border:1px solid transparent
}
.btn-primary{background:var(--link);color:#fff}
.btn-primary:hover{background:var(--link-hover)}
.btn-secondary{background:#fff;color:var(--ink);border-color:#B7C4CF}
.btn-secondary:hover{background:var(--bg-alt)}

.calc-error{color:var(--warn);background:var(--warn-bg);border:1px solid #E5C3AC;border-radius:4px;padding:.6rem .8rem;margin-top:.9rem}
.calc-error[hidden]{display:none}

/* ---------- Results ---------- */
.calc-results{
  margin-top:1.1rem;border:1px solid #BCDCC9;border-radius:var(--radius);
  background:var(--result-bg);padding:1rem 1.1rem
}
.calc-results[hidden]{display:none}
.result-main .result-label{color:var(--ink-soft);font-size:.95rem}
.result-main .result-value{display:block;color:var(--result);font-size:2rem;font-weight:700;line-height:1.2;margin-top:.1rem}
.result-table{width:100%;border-collapse:collapse;margin-top:.8rem;font-size:.98rem}
.result-table th,.result-table td{text-align:left;padding:.45rem .5rem;border-top:1px solid #CBE3D5}
.result-table td:last-child,.result-table th:last-child{text-align:right;font-variant-numeric:tabular-nums}
.result-note{color:var(--ink-soft);font-size:.9rem;margin:.7rem 0 0}

/* ---------- Content blocks ---------- */
.formula{
  background:var(--bg-alt);border:1px solid var(--border);border-left:4px solid var(--link);
  border-radius:4px;padding:.7rem .9rem;margin:.9rem 0;overflow-x:auto;
  font-size:1.02rem
}
.content-table{width:100%;border-collapse:collapse;margin:1rem 0;font-size:.97rem}
.content-table th,.content-table td{border:1px solid var(--border);padding:.5rem .6rem;text-align:left;vertical-align:top}
.content-table th{background:var(--bg-alt)}
.content-table td.num{text-align:right;font-variant-numeric:tabular-nums}

.faq h3{margin-top:1.25rem}
.disclaimer{color:var(--ink-soft);font-size:.9rem;border-top:1px solid var(--border);margin-top:2rem;padding-top:.8rem}

/* ---------- Cards / grids ---------- */
.tile-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:.9rem;margin:1rem 0;padding:0;list-style:none}
.tile{border:1px solid var(--border);border-radius:var(--radius);background:#fff}
.tile a{display:block;padding:.85rem .95rem;height:100%;color:var(--ink)}
.tile a:hover,.tile a:focus{background:var(--bg-alt);text-decoration:none}
.tile .tile-name{color:var(--link);font-weight:600;display:block;margin-bottom:.25rem}
.tile a:hover .tile-name{text-decoration:underline}
.tile .tile-desc{font-size:.92rem;color:var(--ink-soft)}

.link-cols{columns:2;column-gap:2rem;padding-left:1.2rem;margin:.75rem 0}
.link-cols li{margin:.3rem 0;break-inside:avoid}

.section-band{background:var(--bg-alt);border-top:1px solid var(--border);border-bottom:1px solid var(--border);padding:1.5rem 0;margin:2rem 0}
.section-band h2{border-bottom:0;margin-top:0}

/* ---------- Hero (homepage) ---------- */
.hero{padding:1.75rem 0 .5rem}
.hero h1{font-size:2rem;margin-bottom:.4rem}
.hero p{color:var(--ink-soft);max-width:62ch;margin-top:0}

/* ---------- Ad slots (reserved space to avoid CLS) ----------
   Only rendered when adsense_client is set in src/templates.py. The
   min-height reserves space so a late-loading ad does not shift content. */
.ad-slot{margin:1.5rem 0;text-align:center;overflow:hidden}
.ad-slot-leaderboard{min-height:100px}
.ad-slot-incontent{min-height:250px}
.ad-slot .adsbygoogle{display:block;min-height:inherit}

.updated{color:var(--ink-soft);font-size:.9rem;margin-top:2rem}

/* ---------- Footer ---------- */
.site-footer{background:var(--band);color:#C9D8E4;margin-top:2.5rem;font-size:.95rem}
.site-footer .wrap{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:1.25rem;padding-top:1.75rem;padding-bottom:1.25rem}
.site-footer h2{color:#fff;font-size:1rem;border:0;margin:0 0 .5rem}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin:.3rem 0}
.site-footer a{color:#C9D8E4}
.site-footer a:hover,.site-footer a:focus{color:#fff}
.footer-legal{border-top:1px solid #2A5878;padding:0.9rem 1rem;text-align:center;color:#9FB6C7;font-size:.85rem}
.footer-legal .wrap{display:block;padding-top:0;padding-bottom:0}

/* ---------- Responsive ---------- */
@media (max-width:640px){
  body{font-size:1rem}
  .calc-grid{grid-template-columns:1fr}
  .link-cols{columns:1}
  h1{font-size:1.5rem}
  .hero h1{font-size:1.6rem}
  .result-main .result-value{font-size:1.7rem}
}

@media print{
  .site-header,.site-nav,.site-footer,.ad-slot,.calc-actions{display:none}
}

@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation:none!important;transition:none!important}
}

/* ---------- Interactive tools (basic, scientific, time zones) ---------- */
.tool-card{max-width:520px}
.tool-card.tool-wide{max-width:none}
.tz-result .result-value{font-size:1.5rem}
.tz-board td:last-child{text-align:right;font-variant-numeric:tabular-nums}

/* Calculator widgets: navy brand theme, rounded, minimal.
   Distinct on purpose from the neutral gray/square convention used by
   other free calculator sites: brand navy shell, blue accent for
   operators and the active Deg/Rad key, brand green for equals
   (matching --result used elsewhere on the site), soft rounded keys
   with no borders instead of a bordered grid, ghost-style toolbar. */
.calc-ui{
  --cbg:#0F2E44; --cpanel:#173F5C; --cborder:#2A5878;
  --ckey:#1E4E6E; --ckey-hover:#265D82; --ckey-active:#2E6C93;
  --cfn:#133C58; --cfn-hover:#1B4A69;
  --cop:#0B5FA5; --cop-hover:#0D6CBB;
  --caccent:#0E7B4B; --caccent-hover:#0B6740;
  --cdanger:#D9631F; --cdanger-hover:#C0541A;
  --cmode:#0B5FA5;
  --ctext:#EAF2F8; --ctext-soft:#9FB6C7;
  --crad:12px;
  background:var(--cbg);border-color:var(--cbg);padding:.7rem;max-width:520px;color:var(--ctext);border-radius:16px
}
.calc-ui.tool-sci{max-width:640px}
.calc-hist{background:var(--cpanel);border:1px solid var(--cborder);border-radius:var(--crad);height:132px;overflow-y:auto;padding:.45rem .7rem;font-size:.97rem;font-variant-numeric:tabular-nums}
.hist-line{display:flex;justify-content:space-between;align-items:baseline;gap:.75rem;padding:.12rem 0;color:var(--ctext-soft)}
.hist-expr{overflow-wrap:anywhere}
.hist-val{font:inherit;background:none;border:0;color:var(--ctext);cursor:pointer;padding:0;font-weight:600;white-space:nowrap}
.hist-val:hover{text-decoration:underline}
.hist-err{color:#f3b199}
.hist-err span:last-child{white-space:nowrap;font-size:.88rem}
.calc-inrow{display:flex;gap:.4rem;margin:.5rem 0}
.calc-in{flex:1;min-width:0;font:inherit;font-size:1.3rem;padding:.5rem .8rem;background:var(--cpanel);color:var(--ctext);border:1px solid var(--cborder);border-radius:var(--crad);font-variant-numeric:tabular-nums}
.calc-in::placeholder{color:var(--ctext-soft)}
.calc-in:focus{outline:2px solid var(--cop-hover);outline-offset:1px;border-color:var(--cop-hover)}
.calc-clear,.calc-enter{font:inherit;font-size:1.25rem;min-width:48px;border:0;cursor:pointer;padding:0;border-radius:var(--crad)}
.calc-clear{background:var(--cfn);color:var(--ctext-soft)}
.calc-clear:hover{background:var(--cfn-hover);color:var(--ctext)}
.calc-enter{background:var(--caccent);color:#fff}
.calc-enter:hover{background:var(--caccent-hover)}
.calc-tools{display:grid;grid-template-columns:repeat(4,1fr);gap:4px;margin-bottom:4px}
.tool-btn{font:inherit;min-height:36px;background:transparent;color:var(--ctext-soft);border:0;border-radius:var(--crad);cursor:pointer;display:flex;align-items:center;justify-content:center;padding:0}
.tool-btn:hover{background:var(--cfn-hover);color:var(--ctext)}
.tool-btn.is-flash{background:var(--caccent);color:#fff}
.tool-btn svg{stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.calc-ui:fullscreen{max-width:none;width:100%;height:100%;display:flex;flex-direction:column;justify-content:center;padding:4vh 8vw;border-radius:0}
.calc-ui:fullscreen .calc-hist{height:28vh}
.calc-ui:fullscreen .key{min-height:8vh;font-size:1.4rem}
.calc-ui:fullscreen .key-fn{font-size:1.15rem}
.keypad{display:grid;gap:6px}
.key{font:inherit;cursor:pointer;padding:0 .2rem}
.calc-ui .key{background:var(--ckey);color:var(--ctext);border:0;border-radius:var(--crad);min-height:46px;font-size:1.1rem;min-width:0;overflow:hidden;white-space:nowrap}
.calc-ui .key:hover{background:var(--ckey-hover)}
.calc-ui .key:active{background:var(--ckey-active)}
.calc-ui .key-fn{font-size:.92rem;background:var(--cfn);color:var(--ctext-soft)}
.calc-ui .key-fn:hover{background:var(--cfn-hover);color:var(--ctext)}
.calc-ui .key-op{font-size:1.2rem;background:var(--cop);color:#fff}
.calc-ui .key-op:hover{background:var(--cop-hover)}
.calc-ui .key-ac{background:var(--cdanger);color:#fff;font-weight:600}
.calc-ui .key-ac:hover{background:var(--cdanger-hover)}
.calc-ui .key-eq{background:var(--caccent);color:#fff;font-weight:600;font-size:1.3rem}
.calc-ui .key-eq:hover{background:var(--caccent-hover)}
.calc-ui .key-mode.is-active{background:var(--cmode);color:#fff}
.calc-ui .key sup{font-size:.62em;vertical-align:super;line-height:0}
.key-tall{grid-row:span 2}
.key-wide{grid-column:span 2}
.calc-help{margin-top:.6rem;font-size:.9rem;color:var(--ctext-soft);background:var(--cpanel);border-radius:var(--crad);padding:.5rem .8rem}
.calc-help code{color:var(--ctext);font-size:.88em}
.calc-ui :focus-visible{outline:2px solid var(--cop-hover);outline-offset:1px}
@media (max-width:640px){
  .calc-ui{padding:.5rem}
  .calc-ui .key{min-height:42px;font-size:1rem}
  .calc-ui .key-fn{font-size:.76rem;padding:0}
  .calc-ui .key-op{font-size:1.1rem}
  .tool-sci .keypad{gap:4px}
  .calc-in{font-size:1.15rem}
}

/* ---------- Quick calculators: percentage, fraction, average ----------
   Light, in-page style matching the rest of the site (.calc-card,
   .result-*), not the dark keypad theme used by basic/scientific. Each
   row computes live as you type, no submit button. */
.quickcalc{display:flex;flex-direction:column;gap:.7rem}
.qc-row{display:flex;flex-wrap:wrap;align-items:center;gap:.5rem;font-size:1.05rem;line-height:2.6}
.qc-row + .qc-row{padding-top:.7rem;border-top:1px solid var(--border)}
.qc-in{width:5.5rem;font:inherit;padding:.4rem .5rem;border:1px solid #B7C4CF;border-radius:4px;text-align:center;background:#fff;color:var(--ink)}
.qc-in:focus{border-color:var(--link);outline:3px solid var(--focus);outline-offset:0}
.qc-select{font:inherit;padding:.4rem .5rem;border:1px solid #B7C4CF;border-radius:4px;background:#fff;color:var(--ink)}
.qc-eq{color:var(--ink-soft)}
.qc-out{font-weight:700;color:var(--result);min-width:2ch;display:inline-block}

.frac{display:inline-flex;flex-direction:column;align-items:stretch;vertical-align:middle;margin:0 .1rem}
.frac .qc-in{width:4.4rem;margin:0}
.frac-bar{border-top:2px solid var(--ink);margin:.15rem 0}
.frac-result{font-weight:700;color:var(--result);white-space:nowrap}

.steps-box{background:#fff;border:1px solid var(--border);border-radius:4px;padding:.7rem .9rem;margin-top:.3rem;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.9rem;white-space:pre-line;color:var(--ink-soft)}

.qc-textarea{width:100%;min-height:4rem;font:inherit;font-size:1.05rem;padding:.6rem .8rem;border:1px solid #B7C4CF;border-radius:4px;resize:vertical;color:var(--ink)}
.qc-textarea:focus{border-color:var(--link);outline:3px solid var(--focus);outline-offset:0}

@media (max-width:640px){
  .qc-row{font-size:1rem;line-height:2.4;gap:.4rem}
  .qc-in{width:4.6rem}
  .frac .qc-in{width:3.8rem}
}

/* ---------- Unit converters ----------
   Two big linked value boxes with a unit select under each, a swap
   button between them, a one-line formula and a collapsible
   "in all units" table. Same light card style as the quick calculators. */
.unitconv{gap:.9rem}
.uc-grid{display:grid;grid-template-columns:1fr auto 1fr;gap:.8rem;align-items:end}
.uc-side{display:flex;flex-direction:column;gap:.4rem;min-width:0}
.uc-label{font-weight:600;font-size:.92rem;color:var(--ink-soft)}
.uc-in{width:100%;box-sizing:border-box;font:inherit;font-size:1.35rem;font-weight:600;padding:.55rem .7rem;border:1px solid #B7C4CF;border-radius:4px;background:#fff;color:var(--ink);font-variant-numeric:tabular-nums}
.uc-in:focus{border-color:var(--link);outline:3px solid var(--focus);outline-offset:0}
.uc-side .qc-select{width:100%;box-sizing:border-box}
.uc-swap{align-self:center;justify-self:center;width:44px;height:44px;border:1px solid #B7C4CF;border-radius:50%;background:#fff;font-size:1.35rem;line-height:1;cursor:pointer;color:var(--link);margin-bottom:.2rem}
.uc-swap:hover{background:var(--bg-alt)}
.uc-eq{align-self:center;justify-self:center;font-size:1.5rem;color:var(--ink-soft);padding-bottom:.6rem}
.uc-cat{display:flex;flex-direction:column;gap:.4rem}
.uc-cat .qc-select{width:100%;box-sizing:border-box}
.uc-formula{margin:0;color:var(--ink-soft);font-size:.98rem;line-height:1.55}
.uc-formula strong{color:var(--result);font-size:1.05rem}
.uc-all summary{cursor:pointer;font-weight:600;color:var(--link);padding:.2rem 0}
.uc-all .result-table{margin-top:.4rem}
.uc-pair{display:flex;gap:.5rem;align-items:center}
.uc-pair .uc-in{flex:1 1 0;width:auto;min-width:0}
.uc-pair .uc-unit{color:var(--ink-soft);font-weight:600}
.table-pair{display:grid;grid-template-columns:1fr 1fr;gap:0 1.2rem}
.table-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}
.table-scroll .content-table{min-width:22rem}
@media (max-width:640px){
  .uc-grid{grid-template-columns:1fr;gap:.6rem}
  .uc-in{font-size:1.2rem}
  .uc-eq{padding:0}
  .table-pair{grid-template-columns:1fr}
}