:root{
  --bg:#f4f8ff; --card:#ffffff; --card-soft:#f8fbff; --line:#dce7f5; --text:#44556e; --muted:#6e7f98;
  --dark:#14233d; --primary:#2046a8; --primary-2:#2f6df6; --accent:#06b6d4; --success:#149c57;
  --shadow:0 18px 48px rgba(20,35,61,.08); --shadow-soft:0 10px 30px rgba(20,35,61,.06); --radius:22px;
}
*{box-sizing:border-box} html{scroll-behavior:smooth}
body{margin:0;font-family:Arial,Helvetica,sans-serif;color:var(--text);background:radial-gradient(circle at top left,#e3efff 0,transparent 28%),radial-gradient(circle at top right,#def7ff 0,transparent 22%),linear-gradient(180deg,#eef5ff 0,#f7faff 24%,#ffffff 100%)}
a{text-decoration:none;color:inherit}.container{width:min(1240px,92%);margin:auto}
.topbar{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.86);backdrop-filter:blur(14px);border-bottom:1px solid rgba(220,231,245,.9)}
.nav{display:flex;align-items:center;justify-content:space-between;padding:14px 0;gap:20px}
.brand{display:flex;align-items:center;gap:12px;font-size:24px;font-weight:800;color:var(--dark)}
.brand i{width:48px;height:48px;border-radius:16px;display:grid;place-items:center;background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;box-shadow:var(--shadow-soft)}
.navlinks{display:flex;gap:18px;flex-wrap:wrap;color:var(--muted);font-weight:700}
.navlinks a{padding:10px 12px;border-radius:12px}.navlinks a:hover{background:#eef5ff;color:var(--primary-2)}
.hero{padding:54px 0 26px}.heroSplit{display:grid;grid-template-columns:1.15fr .85fr;gap:24px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.heroCard,.sideCard,.contentCard,.catCard,.calcCard,.footcard{padding:30px}
.heroCard{background:linear-gradient(135deg,rgba(32,70,168,.04),rgba(6,182,212,.05)),var(--card)}
.eyebrow{display:inline-flex;align-items:center;gap:8px;background:#dde9ff;color:var(--primary);padding:10px 14px;border-radius:999px;font-size:14px;font-weight:700}
h1{margin:16px 0 14px;font-size:clamp(36px,5vw,60px);line-height:1.04;color:var(--dark)} h2{font-size:34px;color:var(--dark);margin:0 0 12px} h3{font-size:22px;color:var(--dark);margin:0 0 12px} p{line-height:1.8;margin:0 0 12px}
.heroBtns{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}
.btn{display:inline-flex;align-items:center;gap:10px;padding:14px 18px;border-radius:14px;font-weight:800;border:none;cursor:pointer;transition:.2s ease}.btn:hover{transform:translateY(-1px)}
.btnPrimary{background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff}.btnLight{background:#eef5ff;color:var(--primary)}
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-top:22px}
.stat{padding:16px;border:1px solid #dce9ff;background:linear-gradient(180deg,#fbfdff,#f3f8ff);border-radius:18px;text-align:center}
.stat strong{display:block;font-size:24px;color:var(--dark);margin-bottom:5px}
.searchbar{display:flex;gap:10px;margin-top:16px}.searchbar input{flex:1}
.categoryGrid,.calcGrid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.catCard,.calcCard{transition:.18s ease}.catCard:hover,.calcCard:hover{transform:translateY(-4px);box-shadow:0 18px 48px rgba(20,35,61,.12)}
.catCard .icon,.calcCard .icon{width:58px;height:58px;border-radius:18px;display:grid;place-items:center;background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;font-size:22px;margin-bottom:14px}
.section{padding:26px 0}
input,select{width:100%;padding:14px 15px;border:1px solid var(--line);border-radius:14px;font-size:15px;background:#fff;color:var(--dark)}
input:focus,select:focus{outline:none;border-color:#8bb7ff;box-shadow:0 0 0 4px rgba(47,109,246,.12)}
label{display:block;font-weight:700;font-size:14px;color:var(--dark);margin:10px 0 6px}
.grid2{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}
.submitBtn{width:100%;margin-top:14px;padding:15px;border:none;border-radius:14px;background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff;font-weight:800;font-size:15px;cursor:pointer}
.resultBox{margin-top:18px;padding:18px 20px;background:#f0fdf4;border:1px solid #bbf7d0;border-radius:18px;color:#166534;line-height:1.85}
.listCols{columns:3;column-gap:26px}.listCols a{display:block;padding:7px 0;color:var(--primary)}
.tagrow{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px}
.tag,.letter{padding:8px 12px;border-radius:999px;background:#edf4ff;border:1px solid #dce9ff;color:var(--primary);font-size:13px;font-weight:700}
.breadcrumb{font-size:14px;color:var(--muted);margin-bottom:10px}
.footer{padding:24px 0 50px}.footergrid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:18px}
.footcard{background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow)}
.footcard ul{padding-left:18px;margin:0}.footcard li{margin-bottom:8px;line-height:1.7}
.notice{padding:14px 16px;background:#fff8e8;border:1px solid #f3de9a;border-radius:14px;color:#725400}
.azRow{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:18px}.smallMuted{color:var(--muted);font-size:14px}
table.dirTable{width:100%;border-collapse:collapse} table.dirTable td,table.dirTable th{border-bottom:1px solid var(--line);padding:12px 8px;text-align:left} table.dirTable th{color:var(--dark)}
.calcPage{display:grid;grid-template-columns:minmax(0,1.2fr) 380px;gap:24px}.calcShell{background:linear-gradient(180deg,#ffffff,#fbfdff)}
.featureStrip{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}
.featureItem{border:1px solid var(--line);background:var(--card-soft);border-radius:16px;padding:14px}.featureItem strong{display:block;color:var(--dark);margin-bottom:4px}
.formCardHeader{display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:8px}
.formulaBox,.infoBox,.exampleBox,.chartCard,.keypadCard{border:1px solid var(--line);background:var(--card-soft);border-radius:18px;padding:18px}
.contentStack{display:grid;gap:18px}
.keypad{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:14px}
.keyBtn{padding:14px;border:none;border-radius:14px;background:#fff;color:var(--dark);font-weight:800;box-shadow:var(--shadow-soft);cursor:pointer}
.keyBtn.operator{background:#eef5ff;color:var(--primary)}.keyBtn.clear{background:#fff1f2;color:#be123c}
.resultStats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:14px}
.resultStat{padding:14px;border:1px solid #d5f0de;background:#f7fffa;border-radius:16px}.resultStat strong{display:block;color:#11663a;font-size:18px;margin-bottom:3px}
.sideCardSticky{position:sticky;top:88px}
.sidebarList a{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 14px;border:1px solid var(--line);border-radius:14px;background:#fff;margin-bottom:10px}
.sidebarList a:hover{background:#f8fbff}
.meterBar{height:12px;background:#e9f0fb;border-radius:999px;overflow:hidden;margin-top:10px}.meterFill{height:100%;background:linear-gradient(90deg,var(--accent),var(--primary-2));border-radius:999px;width:0%}
.chartWrap{height:280px}
@media(max-width:1100px){.categoryGrid,.calcGrid{grid-template-columns:repeat(2,1fr)}.heroSplit,.footergrid,.calcPage{grid-template-columns:1fr}.listCols{columns:2}.sideCardSticky{position:static}}
@media(max-width:700px){.nav{flex-direction:column;align-items:flex-start}.stats,.categoryGrid,.calcGrid,.grid2,.grid3,.featureStrip,.resultStats{grid-template-columns:1fr}.heroCard,.sideCard,.contentCard,.catCard,.calcCard,.footcard{padding:20px}.listCols{columns:1}}

.classic-calc-wrap{
  border:1px solid #bfcad8;
  border-radius:0;
  background:#e8edf3;
  padding:14px;
  box-shadow:none;
}
.classic-display-top{
  width:100%;
  background:#234f86;
  color:#fff;
  text-align:right;
  font-weight:700;
  font-size:18px;
  padding:6px 10px;
  border:1px solid #5479aa;
  margin-bottom:10px;
  min-height:32px;
}
.classic-display-main{
  width:100%;
  background:#fff;
  color:#111827;
  text-align:right;
  font-weight:700;
  font-size:28px;
  padding:10px 12px;
  border:1px solid #9fb2c9;
  margin-bottom:10px;
  min-height:52px;
}
.classic-mode-row{
  display:flex;
  align-items:center;
  gap:8px;
  flex-wrap:wrap;
  margin-bottom:8px;
}
.classic-mode{
  display:inline-flex;
  align-items:center;
  gap:4px;
  font-size:13px;
  color:#1f2937;
}
.classic-grid{
  display:grid;
  grid-template-columns:repeat(10, 1fr);
  gap:4px;
}
.classic-btn{
  min-height:32px;
  border:1px solid #8aa5c4;
  background:#d9e2ec;
  color:#111827;
  font-weight:700;
  font-size:14px;
  border-radius:3px;
  cursor:pointer;
}
.classic-btn:hover{filter:brightness(.98)}
.classic-btn.fn{background:#e7edf4}
.classic-btn.op{background:#cfdceb}
.classic-btn.eq{background:#bcd0e7}
.classic-btn.mem{background:#e7edf4}
.classic-btn.dark{background:#d4dfeb}
.classic-wide-2{grid-column:span 2}
.classic-wide-3{grid-column:span 3}
@media(max-width:1100px){
  .classic-grid{grid-template-columns:repeat(5, 1fr)}
}