:root {
  color-scheme: dark;
  --ink: #f6f8ff;
  --muted: #9ba7c0;
  --faint: #6d7890;
  --bg: #080c18;
  --panel: #101728;
  --panel-2: #151e33;
  --line: #28334d;
  --blue: #8ba4ff;
  --mint: #78f0c7;
  --orange: #ffb86b;
  --red: #ff7f8e;
  --shadow: 0 24px 64px rgba(0, 0, 0, .28);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  background:
    linear-gradient(rgba(139,164,255,.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(139,164,255,.035) 1px, transparent 1px),
    var(--bg);
  background-size: 32px 32px;
  color: var(--ink);
  font-size: 16px;
  line-height: 1.55;
}

a { color: inherit; }
button, input, select { font: inherit; }
button, select { cursor: pointer; }
button:focus-visible, input:focus-visible, select:focus-visible, a:focus-visible {
  outline: 3px solid rgba(120,240,199,.55);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  left: 1rem;
  top: -5rem;
  z-index: 100;
  padding: .7rem 1rem;
  background: var(--mint);
  color: #07100e;
  border-radius: .5rem;
  font-weight: 800;
}
.skip-link:focus { top: 1rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(8, 12, 24, .88);
  border-bottom: 1px solid rgba(139,164,255,.18);
  backdrop-filter: blur(18px);
}
.nav-shell {
  width: min(1180px, calc(100% - 2rem));
  min-height: 70px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 1.2rem;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: .7rem;
  text-decoration: none;
  font-weight: 850;
  letter-spacing: -.03em;
  white-space: nowrap;
}
.brand-mark {
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  color: var(--mint);
  border: 2px solid currentColor;
  border-left-width: 7px;
  border-right-width: 7px;
  border-radius: 5px;
  font-size: 0;
}
.brand em { color: var(--mint); font-style: normal; }
.nav-toggle {
  display: none;
  margin-left: auto;
  padding: .55rem .75rem;
  color: var(--ink);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: .55rem;
}
.main-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: .2rem;
}
.main-nav a {
  padding: .55rem .65rem;
  color: var(--muted);
  text-decoration: none;
  border-radius: .45rem;
  font-size: .89rem;
  font-weight: 680;
}
.main-nav a:hover, .main-nav a[aria-current="page"] { color: var(--ink); background: var(--panel-2); }

.shell { width: min(1180px, calc(100% - 2rem)); margin: 0 auto; }
.page-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 2rem;
  padding: 4rem 0 2rem;
}
.eyebrow {
  margin: 0 0 .65rem;
  color: var(--mint);
  font-size: .79rem;
  font-weight: 850;
  letter-spacing: .13em;
  text-transform: uppercase;
}
h1, h2, h3 { line-height: 1.08; letter-spacing: -.04em; }
h1 { max-width: 780px; margin: 0; font-size: clamp(2.35rem, 5vw, 5.2rem); }
h2 { margin: 0 0 1rem; font-size: clamp(1.7rem, 3vw, 2.55rem); }
h3 { margin: 0 0 .55rem; font-size: 1.08rem; }
.lede { max-width: 720px; margin: 1rem 0 0; color: var(--muted); font-size: 1.08rem; }
.formula-chip {
  padding: .65rem .8rem;
  color: var(--blue);
  background: rgba(139,164,255,.08);
  border: 1px solid rgba(139,164,255,.25);
  border-radius: .55rem;
  font: 700 .85rem ui-monospace, SFMono-Regular, Menlo, monospace;
  white-space: nowrap;
}

.tool-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(320px, .92fr);
  gap: 1rem;
  align-items: stretch;
}
.panel {
  background: linear-gradient(155deg, rgba(21,30,51,.98), rgba(13,19,33,.98));
  border: 1px solid var(--line);
  border-radius: 1rem;
  box-shadow: var(--shadow);
}
.control-panel { padding: clamp(1.1rem, 3vw, 2rem); }
.result-panel { padding: clamp(1.1rem, 3vw, 2rem); position: relative; overflow: hidden; }
.result-panel::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 3px;
  background: linear-gradient(90deg, var(--mint), var(--blue));
}
.panel-label {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: .8rem;
  font-weight: 800;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.mode-switch {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .25rem;
  padding: .25rem;
  margin-bottom: 1.4rem;
  background: #090e1c;
  border: 1px solid var(--line);
  border-radius: .7rem;
}
.mode-switch button {
  min-height: 44px;
  padding: .6rem .8rem;
  color: var(--muted);
  background: transparent;
  border: 0;
  border-radius: .5rem;
  font-weight: 750;
}
.mode-switch button.active { color: #07100e; background: var(--mint); }
.input-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; }
.input-grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.field { display: grid; gap: .42rem; }
.field.full { grid-column: 1 / -1; }
.field label { color: var(--muted); font-size: .86rem; font-weight: 700; }
.input-wrap { position: relative; }
.input-wrap input, .field select, .filter-input {
  width: 100%;
  min-height: 52px;
  padding: .78rem .9rem;
  color: var(--ink);
  background: #090e1c;
  border: 1px solid var(--line);
  border-radius: .65rem;
  font-size: 1rem;
  font-variant-numeric: tabular-nums;
}
.input-wrap input { padding-right: 3.5rem; }
.input-wrap input:hover, .field select:hover, .filter-input:hover { border-color: #3b4a6d; }
.input-wrap input:focus, .field select:focus, .filter-input:focus { border-color: var(--mint); outline: 0; box-shadow: 0 0 0 3px rgba(120,240,199,.12); }
.unit {
  position: absolute;
  right: .85rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--faint);
  font-size: .82rem;
  font-weight: 800;
  pointer-events: none;
}
.presets { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: .8rem; }
.preset {
  padding: .4rem .65rem;
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: .8rem;
  font-weight: 750;
}
.preset:hover, .preset.active { color: var(--ink); border-color: var(--blue); background: rgba(139,164,255,.1); }
.helper { margin: .7rem 0 0; color: var(--faint); font-size: .83rem; }
.divider { height: 1px; margin: 1.4rem 0; background: var(--line); }

.result-main { margin: .2rem 0 1.5rem; }
.result-number {
  display: block;
  overflow-wrap: anywhere;
  color: var(--mint);
  font-size: clamp(2.1rem, 5vw, 4.65rem);
  font-weight: 880;
  line-height: 1;
  letter-spacing: -.06em;
  font-variant-numeric: tabular-nums;
}
.result-caption { display: block; margin-top: .65rem; color: var(--muted); }
.metric-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .65rem; }
.metric {
  min-height: 90px;
  padding: .9rem;
  background: rgba(8,12,24,.64);
  border: 1px solid var(--line);
  border-radius: .7rem;
}
.metric span { display: block; color: var(--faint); font-size: .76rem; font-weight: 800; letter-spacing: .06em; text-transform: uppercase; }
.metric strong { display: block; margin-top: .35rem; color: var(--ink); font-size: 1.05rem; font-variant-numeric: tabular-nums; }
.quality { display: inline-flex; align-items: center; gap: .45rem; margin-top: 1rem; padding: .45rem .7rem; border-radius: 999px; font-size: .82rem; font-weight: 800; }
.quality.good { color: var(--mint); background: rgba(120,240,199,.1); }
.quality.ok { color: var(--orange); background: rgba(255,184,107,.1); }
.quality.low { color: var(--red); background: rgba(255,127,142,.1); }
.action-row { display: flex; flex-wrap: wrap; gap: .65rem; margin-top: 1.25rem; }
.button {
  min-height: 44px;
  padding: .65rem .9rem;
  color: #07100e;
  background: var(--mint);
  border: 1px solid var(--mint);
  border-radius: .58rem;
  font-weight: 820;
}
.button.secondary { color: var(--ink); background: transparent; border-color: var(--line); }
.button:hover { filter: brightness(1.05); }

.tool-strip { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: .75rem; margin: 1rem 0 4.5rem; }
.tool-card {
  min-height: 118px;
  padding: 1rem;
  color: var(--muted);
  background: rgba(16,23,40,.8);
  border: 1px solid var(--line);
  border-radius: .8rem;
  text-decoration: none;
  transition: transform .18s ease, border-color .18s ease;
}
.tool-card:hover { transform: translateY(-3px); border-color: var(--blue); color: var(--ink); }
.tool-card strong { display: block; margin-bottom: .35rem; color: var(--ink); font-size: .93rem; }
.tool-card span { font-size: .81rem; line-height: 1.35; }
.tool-index { color: var(--mint); font: 800 .72rem ui-monospace, monospace; }

.content-section { padding: 4.5rem 0; border-top: 1px solid var(--line); }
.content-grid { display: grid; grid-template-columns: minmax(0, .7fr) minmax(0, 1.3fr); gap: 4rem; }
.prose { max-width: 760px; }
.prose p, .prose li { color: var(--muted); }
.prose code { color: var(--mint); font-family: ui-monospace, monospace; }
.prose a { color: var(--blue); }
.formula-box { padding: 1.2rem; background: var(--panel); border: 1px solid var(--line); border-left: 3px solid var(--mint); border-radius: .7rem; font: 700 .95rem/1.8 ui-monospace, monospace; }
.steps { display: grid; gap: .8rem; counter-reset: step; }
.step { position: relative; padding: 1.1rem 1.1rem 1.1rem 3.5rem; background: rgba(16,23,40,.68); border: 1px solid var(--line); border-radius: .7rem; }
.step::before { counter-increment: step; content: counter(step, decimal-leading-zero); position: absolute; left: 1rem; top: 1.08rem; color: var(--mint); font: 800 .78rem ui-monospace, monospace; }
.step p { margin: .3rem 0 0; color: var(--muted); font-size: .92rem; }

.table-tools { display: flex; align-items: end; gap: 1rem; margin: 0 0 1rem; }
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: .8rem; }
table { width: 100%; border-collapse: collapse; min-width: 660px; background: rgba(16,23,40,.82); }
th, td { padding: .85rem 1rem; text-align: left; border-bottom: 1px solid var(--line); font-variant-numeric: tabular-nums; }
th { color: var(--faint); font-size: .76rem; letter-spacing: .06em; text-transform: uppercase; }
td { color: var(--muted); }
td:first-child { color: var(--ink); font-weight: 720; }
tbody tr:last-child td { border-bottom: 0; }
tbody tr:hover { background: rgba(139,164,255,.05); }
.tabs { display: flex; flex-wrap: wrap; gap: .5rem; margin-bottom: 1rem; }
.tabs button { padding: .5rem .75rem; color: var(--muted); background: var(--panel); border: 1px solid var(--line); border-radius: .5rem; font-weight: 750; }
.tabs button.active { color: #07100e; background: var(--mint); border-color: var(--mint); }

.notice { margin-top: 1rem; padding: .9rem 1rem; color: var(--muted); background: rgba(139,164,255,.07); border: 1px solid rgba(139,164,255,.22); border-radius: .7rem; font-size: .86rem; }
.site-footer { margin-top: 4rem; border-top: 1px solid var(--line); background: rgba(5,8,16,.8); }
.footer-shell { width: min(1180px, calc(100% - 2rem)); margin: 0 auto; padding: 2rem 0; display: flex; justify-content: space-between; gap: 1rem; color: var(--faint); font-size: .82rem; }
.footer-links { display: flex; flex-wrap: wrap; gap: 1rem; }
.footer-links a { color: var(--muted); text-decoration: none; }
.footer-links a:hover { color: var(--ink); }

.static-page { max-width: 800px; padding: 4.5rem 0; }
.static-page h1 { font-size: clamp(2.4rem, 5vw, 4.5rem); }
.static-page h2 { margin-top: 2.5rem; font-size: 1.55rem; }
.static-page p, .static-page li { color: var(--muted); }
.static-page strong { color: var(--ink); }

@media (max-width: 980px) {
  .nav-shell { flex-wrap: wrap; padding: .85rem 0; }
  .nav-toggle { display: block; }
  .main-nav { display: none; width: 100%; margin: 0; padding-top: .5rem; grid-template-columns: repeat(2, 1fr); }
  .main-nav.open { display: grid; }
  .main-nav a { border: 1px solid var(--line); }
  .tool-layout, .content-grid { grid-template-columns: 1fr; }
  .content-grid { gap: 1.5rem; }
  .tool-strip { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  .shell, .nav-shell, .footer-shell { width: min(100% - 1.1rem, 1180px); }
  .page-head { grid-template-columns: 1fr; align-items: start; padding-top: 2.6rem; }
  .page-head .formula-chip { justify-self: start; }
  h1 { font-size: clamp(2.25rem, 12vw, 3.45rem); }
  .input-grid, .input-grid.three, .metric-grid { grid-template-columns: 1fr; }
  .tool-strip { grid-template-columns: 1fr; }
  .tool-card { min-height: auto; }
  .footer-shell { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; transition: none !important; }
}