/* CalcKit — Material You (M3) design system.
   Tonal palette from an indigo/violet seed. System fonts only, zero external requests.
   Performance: transitions on transform/opacity only; backdrop-filter ONLY on the
   small sticky app bar (with rgba fallback); no infinite animations. */
*{box-sizing:border-box;margin:0;padding:0}
:root{
  --m3-primary:#3f4fc4;
  --m3-on-primary:#ffffff;
  --m3-primary-container:#e1e3ff;
  --m3-on-primary-container:#0b0f66;
  --m3-secondary:#5a5d72;
  --m3-secondary-container:#e2e1f9;
  --m3-on-secondary-container:#191a2c;
  --m3-tertiary:#6f43c0;
  --m3-tertiary-container:#eddcff;
  --m3-on-tertiary-container:#2a0a63;
  --m3-error:#ba1a1a;
  --m3-surface:#fdf8ff;
  --m3-surface-lowest:#ffffff;
  --m3-surface-low:#f7f2fa;
  --m3-surface-container:#f1edf6;
  --m3-surface-high:#ebe5f1;
  --m3-surface-highest:#e5dfeb;
  --m3-on-surface:#1d1b20;
  --m3-on-surface-variant:#49454f;
  --m3-outline:#79747e;
  --m3-outline-variant:#cac4d0;
  --m3-shadow-sm:0 1px 2px rgba(29,27,32,.06),0 4px 12px -6px rgba(63,79,196,.16);
  --m3-shadow-lg:0 2px 6px rgba(29,27,32,.08),0 16px 34px -14px rgba(63,79,196,.30);
  --ease:cubic-bezier(.2,0,0,1);
  --appbar-h:64px;
}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important}
}
body{
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,"Noto Sans","Noto Sans Devanagari",Arial,sans-serif;
  background-color:var(--m3-surface);
  background-image:linear-gradient(180deg,#efeaff 0%,rgba(239,234,255,0) 360px);
  color:var(--m3-on-surface);
  line-height:1.6;font-size:16px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
::selection{background:var(--m3-primary-container)}
.wrap{max-width:920px;margin:0 auto;padding:0 20px}
a{color:var(--m3-primary)}
:focus-visible{outline:2px solid var(--m3-primary);outline-offset:3px;border-radius:8px}

/* ---------- M3 top app bar (glass, restrained: blur only here) ---------- */
header.site{
  position:sticky;top:0;z-index:50;
  min-height:var(--appbar-h);
  display:flex;align-items:center;
  background:rgba(253,248,255,.88);
  border-bottom:1px solid var(--m3-outline-variant);
}
@supports ((-webkit-backdrop-filter:blur(10px)) or (backdrop-filter:blur(10px))){
  header.site{
    background:rgba(253,248,255,.68);
    -webkit-backdrop-filter:blur(10px) saturate(1.35);
    backdrop-filter:blur(10px) saturate(1.35);
  }
}
header.site .wrap{width:100%;display:flex;align-items:center;justify-content:space-between;gap:12px}
.logo{font-weight:800;font-size:1.3rem;letter-spacing:-.01em;color:var(--m3-on-surface);text-decoration:none;display:inline-flex;align-items:center;gap:8px}
.logo span{color:var(--m3-primary)}
.langsw{font-size:.875rem;font-weight:600}
.langsw a{color:var(--m3-primary);text-decoration:none;padding:10px 18px;border-radius:999px;display:inline-block;position:relative;transition:opacity .18s var(--ease)}
.langsw a::after{content:"";position:absolute;inset:0;border-radius:inherit;background:var(--m3-primary);opacity:0;transition:opacity .18s var(--ease)}
.langsw a:hover::after{opacity:.08}
.langsw a:active::after{opacity:.14}

/* ---------- type scale ---------- */
nav.crumbs{font-size:.85rem;color:var(--m3-on-surface-variant);margin:20px 0 6px}
nav.crumbs a{color:var(--m3-primary);text-decoration:none;font-weight:600}
h1{font-size:clamp(1.75rem,4.5vw,2.4rem);line-height:1.2;letter-spacing:-.02em;font-weight:800;margin:8px 0 12px;color:var(--m3-on-surface);text-wrap:balance}
h2{font-size:1.35rem;font-weight:700;letter-spacing:-.01em;margin:34px 0 12px;color:var(--m3-on-surface)}
p{margin:0 0 12px}
.lead{font-size:1.075rem;color:var(--m3-on-surface-variant);max-width:62ch}

/* ---------- tool card ---------- */
.toolcard{
  background:var(--m3-surface-lowest);
  border:1px solid var(--m3-outline-variant);
  border-radius:24px;
  padding:clamp(18px,4vw,28px);
  margin:20px 0 10px;
  box-shadow:var(--m3-shadow-sm);
}
@media(min-width:1024px){
  .toolcard{position:sticky;top:calc(var(--appbar-h) + 16px)}
}
.toolcard label{display:block;font-weight:600;font-size:.92rem;margin:14px 0 6px;color:var(--m3-on-surface)}
.toolcard label:first-child{margin-top:0}
.toolcard input[type=number],.toolcard input[type=date],.toolcard input[type=time],
.toolcard input[type=text],.toolcard select,.toolcard textarea{
  width:100%;min-height:52px;padding:12px 16px;
  border:1.5px solid var(--m3-outline-variant);border-radius:16px;
  font-size:1rem;font-family:inherit;color:var(--m3-on-surface);
  background:var(--m3-surface-lowest);
}
.toolcard select{
  appearance:none;-webkit-appearance:none;
  background-image:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2349454f' stroke-width='2.4' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat:no-repeat;background-position:right 16px center;padding-right:44px;
}
.toolcard textarea{min-height:128px;resize:vertical;line-height:1.55}
.toolcard input:focus,.toolcard select:focus,.toolcard textarea:focus{
  outline:none;border-color:var(--m3-primary);
  box-shadow:0 0 0 3px rgba(63,79,196,.14);
}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.grid3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:12px}
@media(max-width:600px){.grid2,.grid3{grid-template-columns:1fr}}

/* ---------- M3 buttons: pill, tonal state layers ---------- */
.btn{
  position:relative;overflow:hidden;isolation:isolate;
  display:inline-flex;align-items:center;justify-content:center;
  min-height:54px;width:100%;padding:12px 28px;margin-top:16px;
  border:0;border-radius:999px;cursor:pointer;
  background:var(--m3-primary);color:var(--m3-on-primary);
  font-size:1.02rem;font-weight:600;font-family:inherit;letter-spacing:.01em;
  box-shadow:0 1px 2px rgba(29,27,32,.14);
  transition:transform .18s var(--ease),opacity .18s var(--ease);
}
.btn::after{content:"";position:absolute;inset:0;border-radius:inherit;background:#fff;opacity:0;transition:opacity .18s var(--ease);z-index:-1}
.btn:hover{transform:translateY(-1px);box-shadow:0 2px 5px rgba(29,27,32,.16),0 10px 22px -10px rgba(63,79,196,.5)}
.btn:hover::after{opacity:.08}
.btn:active{transform:translateY(0)}
.btn:active::after{opacity:.16}

/* ---------- result: tonal container ---------- */
.result{
  margin-top:16px;background:var(--m3-primary-container);color:var(--m3-on-primary-container);
  border-radius:20px;padding:18px 16px;min-height:66px;
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;
  font-size:1.4rem;font-weight:700;text-align:center;overflow-wrap:anywhere;
}
.result small{font-size:.82rem;font-weight:500;opacity:.72}
.hint{font-size:.85rem;color:var(--m3-on-surface-variant);margin-top:8px}

/* ---------- steps: numbered tonal chips ---------- */
ol.steps{margin:8px 0 12px;list-style:none;counter-reset:step}
ol.steps li{counter-increment:step;position:relative;padding:9px 0 9px 50px;margin-bottom:6px;color:var(--m3-on-surface)}
ol.steps li::before{
  content:counter(step);position:absolute;left:0;top:7px;
  width:34px;height:34px;border-radius:50%;
  background:var(--m3-secondary-container);color:var(--m3-on-secondary-container);
  font-weight:700;font-size:.92rem;display:flex;align-items:center;justify-content:center;
}

/* ---------- FAQ: M3 expansion ---------- */
details.faq{
  background:var(--m3-surface-low);border:1px solid var(--m3-outline-variant);
  border-radius:16px;margin-bottom:10px;overflow:hidden;
}
details.faq[open]{border-color:var(--m3-primary);background:var(--m3-surface-lowest)}
details.faq summary{
  list-style:none;cursor:pointer;font-weight:600;color:var(--m3-on-surface);
  padding:16px 54px 16px 20px;position:relative;
}
details.faq summary::-webkit-details-marker{display:none}
details.faq summary::after{
  content:"+";position:absolute;right:16px;top:50%;margin-top:-15px;
  width:30px;height:30px;border-radius:50%;font-size:1.35rem;font-weight:400;line-height:30px;text-align:center;
  color:var(--m3-primary);background:var(--m3-primary-container);
  transition:transform .22s var(--ease);
}
details.faq[open] summary::after{transform:rotate(45deg)}
details.faq summary:hover{color:var(--m3-primary)}
details.faq p{margin:0;padding:0 20px 18px;color:var(--m3-on-surface-variant)}

/* ---------- tool grid cards ---------- */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:14px;margin:16px 0}
.cards a{
  background:var(--m3-surface-lowest);border:1px solid var(--m3-outline-variant);
  border-radius:20px;padding:20px;text-decoration:none;color:var(--m3-on-surface);display:block;
  transition:transform .2s var(--ease);
}
.cards a:hover{transform:translateY(-3px);border-color:var(--m3-primary);box-shadow:var(--m3-shadow-lg)}
.cards b{color:var(--m3-on-surface);display:block;margin-bottom:6px;font-size:1.02rem}
.cards span{font-size:.88rem;color:var(--m3-on-surface-variant)}

/* ---------- calculator: tonal dark ---------- */
.calc{max-width:360px;margin:0 auto;background:#1d1b20;border-radius:28px;padding:14px;box-shadow:0 10px 32px -12px rgba(29,27,32,.5)}
.cdisplay{
  color:#fff;font-size:2.6rem;font-weight:600;text-align:right;
  padding:22px 14px 12px;min-height:96px;overflow-x:auto;white-space:nowrap;
  font-variant-numeric:tabular-nums;letter-spacing:-.01em;
}
.cgrid{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}
.cgrid button{
  font-size:1.3rem;min-height:62px;border:0;border-radius:16px;cursor:pointer;font-family:inherit;
  background:rgba(255,255,255,.09);color:#fff;font-weight:500;
  transition:transform .12s var(--ease),opacity .12s var(--ease);
}
.cgrid button:hover{transform:scale(1.045)}
.cgrid button:active{transform:scale(.96);opacity:.85}
.cgrid button.op{background:var(--m3-primary-container);color:var(--m3-on-primary-container);font-weight:700}
.cgrid button.eq{background:var(--m3-primary);color:var(--m3-on-primary);font-weight:700}

/* ---------- footer: tonal surface ---------- */
footer.site{background:var(--m3-surface-container);color:var(--m3-on-surface-variant);margin-top:60px;padding:42px 0 34px;font-size:.92rem;border-top:1px solid var(--m3-outline-variant)}
footer.site a{color:var(--m3-primary);text-decoration:none;font-weight:600;display:inline-block;margin:0 18px 10px 0;padding:4px 0}
footer.site a:hover{text-decoration:underline}
footer.site .flang{margin-top:16px;display:flex;flex-wrap:wrap;gap:4px 8px;align-items:center}

/* ---------- small components ---------- */
.checkline{display:flex;align-items:center;gap:12px;margin:14px 0;font-size:.95rem;font-weight:500;cursor:pointer}
.checkline input{width:22px;height:22px;flex:none;margin:0;accent-color:var(--m3-primary);cursor:pointer}
.oprow{display:flex;gap:10px;align-items:center}
.oprow select{width:88px;flex:none;text-align:center;font-size:1.25rem;font-weight:700;border-radius:999px}
/* M3 segmented buttons */
.modebtns{display:flex;margin:6px 0;border:1.5px solid var(--m3-outline);border-radius:999px;overflow:hidden;background:var(--m3-surface-lowest)}
.modebtns button{
  flex:1;border:0;background:transparent;cursor:pointer;font-family:inherit;
  font-weight:600;font-size:.9rem;color:var(--m3-on-surface);
  min-height:50px;padding:10px 6px;transition:opacity .18s var(--ease);
}
.modebtns button+button{border-left:1px solid var(--m3-outline-variant)}
.modebtns button.on{background:var(--m3-secondary-container);color:var(--m3-on-secondary-container)}
@media(max-width:600px){
  .modebtns{flex-direction:column;border-radius:24px}
  .modebtns button+button{border-left:0;border-top:1px solid var(--m3-outline-variant)}
}
.hidden{display:none!important}
.badge{display:inline-block;background:var(--m3-tertiary-container);color:var(--m3-on-tertiary-container);font-size:.75rem;font-weight:700;letter-spacing:.03em;border-radius:999px;padding:5px 14px;margin-bottom:10px}
/* language gateway */
.gate{display:flex;gap:18px;flex-wrap:wrap;justify-content:center;margin:34px 0}
.gate a{
  flex:1;min-width:250px;max-width:360px;background:var(--m3-surface-lowest);
  border:1.5px solid var(--m3-outline-variant);border-radius:28px;
  padding:42px 24px;text-align:center;text-decoration:none;color:var(--m3-on-surface);
  transition:transform .2s var(--ease);
}
.gate a:hover{transform:translateY(-4px);border-color:var(--m3-primary);box-shadow:var(--m3-shadow-lg)}
.gate .big{font-size:3.2rem}
.gate b{font-size:1.35rem;color:var(--m3-on-surface);display:block;margin:12px 0 6px}
.gate span{color:var(--m3-on-surface-variant)}