:root {
  --bg: #05080c;
  --bg-2: #070d12;
  --panel: #0a1118;
  --panel-2: #0d161f;
  --ink: #e8f1f5;
  --muted: #8ba0ad;
  --faint: #5f7480;
  --line: #1a2a34;
  --line-strong: #2a4653;
  --accent: #53f0c2;
  --accent-dim: #27b992;
  --cyan: #6bd5ff;
  --danger: #ff6b7a;
  --warn: #ffbd6b;
  --sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  --radius: 4px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; color-scheme: dark; }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: 1rem;
  color: var(--ink);
  background-color: var(--bg);
  background-image:
    linear-gradient(rgba(83, 240, 194, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(83, 240, 194, 0.035) 1px, transparent 1px),
    radial-gradient(circle at 78% -10%, rgba(83, 240, 194, 0.10), transparent 34rem);
  background-size: 48px 48px, 48px 48px, auto;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
::selection { background: rgba(83, 240, 194, 0.25); color: #fff; }
a { color: var(--cyan); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: var(--accent); }
a:focus-visible, button:focus-visible, summary:focus-visible, input:focus-visible, select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.skip { position: absolute; left: -999px; top: 0; background: var(--accent); color: #02100b; padding: .6rem 1rem; z-index: 30; font-family: var(--mono); }
.skip:focus { left: 1rem; top: 1rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  width: 100%;
  padding: 0 max(1rem, calc((100vw - 1180px) / 2));
  min-height: 68px;
  display: flex;
  align-items: center;
  gap: 1rem;
  background: rgba(5, 8, 12, 0.86);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}
.brand { display: inline-flex; align-items: center; gap: .55rem; color: var(--ink); text-decoration: none; font-family: var(--mono); font-size: .88rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; }
.brand-mark { display: block; width: 28px; height: 28px; flex: 0 0 28px; }
.brand-word { display: inline-flex; align-items: center; white-space: nowrap; line-height: 1; }
.brand-vane { color: var(--ink); font-weight: 750; }
.brand-cost { color: var(--accent); font-weight: 500; }
.brand-cursor { color: var(--accent); font-size: .72em; margin-left: .16em; opacity: .9; }
.nav { margin-left: auto; display: flex; flex-wrap: wrap; gap: .15rem; }
.nav a { color: var(--muted); text-decoration: none; padding: .45rem .55rem; font-family: var(--mono); font-size: .86rem; letter-spacing: .06em; text-transform: uppercase; border-bottom: 1px solid transparent; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--accent); border-bottom-color: var(--accent); }
.nav-short, .lang-short { display: none; }
.lang { color: var(--ink); text-decoration: none; border: 1px solid var(--line-strong); padding: .38rem .65rem; font-family: var(--mono); font-size: .82rem; letter-spacing: .08em; text-transform: uppercase; }
.lang:hover { border-color: var(--accent); color: var(--accent); }

main { width: min(1180px, calc(100% - 2rem)); margin: 0 auto; }
.hero { padding: clamp(1.8rem, 3.2vw, 2.4rem) 0 1rem; max-width: 920px; }
.hero.compact { padding-bottom: 1rem; }
.hero-meta { display: flex; flex-wrap: wrap; gap: .45rem; margin-bottom: 1.2rem; }
.chip { display: inline-flex; align-items: center; gap: .4rem; border: 1px solid var(--line); background: rgba(10, 17, 24, .8); color: var(--muted); padding: .32rem .5rem; font-family: var(--mono); font-size: .8rem; letter-spacing: .08em; text-transform: uppercase; }
.chip-live { color: var(--accent); border-color: rgba(83, 240, 194, .35); }
.chip-live i { width: 6px; height: 6px; display: inline-block; background: var(--accent); box-shadow: 0 0 8px var(--accent); animation: pulse 2.4s ease-in-out infinite; }
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: .35; } }
.eyebrow { margin: 0 0 .85rem; color: var(--accent); font-family: var(--mono); font-size: .82rem; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; }
h1 { margin: 0 0 .85rem; font-family: var(--sans); font-size: clamp(2.1rem, 4vw, 3.4rem); line-height: .98; letter-spacing: -.055em; font-weight: 750; text-wrap: balance; }
h1 span { color: var(--accent); }
.hero.compact h1 { font-size: clamp(2rem, 4.5vw, 3.35rem); line-height: 1.04; }
.lede { margin: 0; color: var(--muted); font-size: clamp(1rem, 1.7vw, 1.14rem); max-width: 800px; line-height: 1.6; text-wrap: pretty; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .6rem; margin: 1.15rem 0 0; }
.btn-primary, .btn-ghost { display: inline-flex; align-items: center; gap: .55rem; padding: .72rem .95rem; font-family: var(--mono); font-size: .8rem; letter-spacing: .06em; text-transform: uppercase; text-decoration: none; border: 1px solid; min-height: 44px; }
.btn-primary { color: #03110c; background: var(--accent); border-color: var(--accent); font-weight: 750; }
.btn-primary:hover { background: #8bffe0; color: #03110c; border-color: #8bffe0; }
.btn-ghost { color: var(--ink); border-color: var(--line-strong); background: rgba(10, 17, 24, .6); }
.btn-ghost:hover { color: var(--accent); border-color: var(--accent); }
.note { color: var(--muted); font-size: .9rem; line-height: 1.55; }
.calc > #result-note { margin: .7rem 1.2rem 0; color: var(--faint); font-family: var(--mono); font-size: .76rem; }
.calc > #result-note:empty { display: none; }
.small { font-size: .82rem; }
.field-src { display: block; margin-top: .3rem; color: var(--faint); font-family: var(--mono); font-size: .76rem; font-weight: 400; letter-spacing: .01em; line-height: 1.4; }
.field-src a { color: var(--cyan); }
.privacy-note { margin: 1rem 1.2rem 0; padding: .75rem .85rem; border: 1px solid #17352d; background: rgba(83, 240, 194, .04); color: #a9c9bd; font-size: .84rem; }
.formula-box { margin: 1.1rem 1.2rem 1.2rem; border: 1px solid var(--line); background: var(--bg-2); padding: .8rem .9rem; }
.formula-box summary { cursor: pointer; color: var(--ink); font-family: var(--mono); font-size: .8rem; letter-spacing: .05em; text-transform: uppercase; }
.formula-box summary::marker { color: var(--accent); }
.formula-box pre { margin: .8rem 0 .55rem; background: #03070a; border: 1px solid var(--line); color: #c8f7e8; padding: .85rem; overflow-x: auto; font-family: var(--mono); font-size: .86rem; line-height: 1.65; }
.formula-box p { margin: .3rem 0; color: var(--muted); font-size: .82rem; }
.noscript { margin: 1rem 0 2rem; border: 1px solid #5b4522; background: #1a1409; padding: 1rem 1.1rem; color: #f2d7a8; }
.noscript p { margin: .4rem 0; }
.noscript a { color: var(--warn); }
.noscript code { font-family: var(--mono); font-size: .8em; color: #ffe7bd; }

.calc {
  position: relative;
  margin: 0 0 3rem;
  background: linear-gradient(180deg, rgba(13, 22, 31, .96), rgba(7, 13, 18, .98));
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  box-shadow: 0 0 0 1px rgba(83, 240, 194, .04) inset, 0 24px 70px rgba(0, 0, 0, .35);
  padding: 0;
  scroll-margin-top: 88px;
}
.calc::before { content: ""; position: absolute; inset: -1px; pointer-events: none; background: linear-gradient(90deg, transparent, rgba(83, 240, 194, .35), transparent); height: 1px; }
.console-bar { display: flex; align-items: center; gap: .55rem; padding: .65rem 1.2rem; border-bottom: 1px solid var(--line); background: rgba(5, 10, 14, .75); color: var(--muted); font-family: var(--mono); font-size: .8rem; letter-spacing: .08em; text-transform: uppercase; }
.console-bar .dot { width: 6px; height: 6px; background: var(--accent); box-shadow: 0 0 8px var(--accent); }
.console-right { margin-left: auto; color: var(--faint); }
.calc-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; flex-wrap: wrap; padding: 1.25rem 1.2rem 0; }
.calc h2 { margin: 0; font-family: var(--sans); font-size: clamp(1.45rem, 2.6vw, 1.95rem); letter-spacing: -.035em; font-weight: 720; }
.presets { display: flex; flex-wrap: wrap; gap: .35rem; }
.presets button { border: 1px solid var(--line-strong); background: rgba(8, 16, 22, .8); color: var(--ink); border-radius: 0; padding: .45rem .6rem; font-family: var(--mono); font-size: .82rem; letter-spacing: .02em; cursor: pointer; min-height: 38px; }
.presets button:hover, .presets button:focus-visible { border-color: var(--accent); color: var(--accent); background: rgba(83, 240, 194, .06); }
.grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .8rem; margin-top: 1.2rem; padding: 0 1.2rem; }
.grid label { display: flex; flex-direction: column; gap: .35rem; color: var(--muted); font-family: var(--mono); font-size: .8rem; font-weight: 500; letter-spacing: .04em; text-transform: uppercase; line-height: 1.4; }
.grid input, .grid select {
  width: 100%; border: 1px solid var(--line-strong); border-radius: 0; padding: .65rem .65rem;
  background: #060d12; color: var(--ink); font-family: var(--mono); font-size: .98rem; min-height: 42px;
}
.grid select { appearance: none; background-image: linear-gradient(45deg, transparent 50%, var(--accent) 50%), linear-gradient(135deg, var(--accent) 50%, transparent 50%); background-position: calc(100% - 13px) 50%, calc(100% - 8px) 50%; background-size: 5px 5px, 5px 5px; background-repeat: no-repeat; padding-right: 1.8rem; }
.grid input:focus, .grid select:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 1px rgba(83, 240, 194, .3), 0 0 18px rgba(83, 240, 194, .08); }
.grid input:disabled { background: #0a0f13; color: var(--faint); border-color: #16222a; }
.error { margin: .9rem 1.2rem 0; color: #ffb8c0; background: rgba(255, 107, 122, .08); border: 1px solid rgba(255, 107, 122, .38); padding: .62rem .75rem; font-family: var(--mono); font-size: .72rem; }
.results { display: grid; grid-template-columns: 1.4fr repeat(4, 1fr); gap: 0; margin-top: 1.2rem; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: #060d12; }
.results > div { border-right: 1px solid var(--line); padding: .85rem 1rem; min-width: 0; }
.results > div:last-child { border-right: 0; }
.results span { display: block; color: var(--faint); font-family: var(--mono); font-size: .8rem; letter-spacing: .07em; text-transform: uppercase; line-height: 1.4; }
.results strong { display: block; margin-top: .35rem; color: var(--ink); font-family: var(--mono); font-size: 1.28rem; font-weight: 500; letter-spacing: -.04em; white-space: normal; overflow-wrap: anywhere; }
.results .result-main { background: rgba(83, 240, 194, .055); border-right-color: rgba(83, 240, 194, .28); }
.results .result-main span { color: #90c9b9; }
.results .result-main strong { color: var(--accent); font-size: clamp(1.55rem, 3.5vw, 2.25rem); text-shadow: 0 0 22px rgba(83, 240, 194, .18); }
.results #break-even { font-size: .95rem; line-height: 1.35; }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: .8rem; margin: 2rem 0 3rem; counter-reset: card; }
.cards article { position: relative; background: rgba(8, 16, 22, .72); border: 1px solid var(--line); border-top-color: var(--line-strong); padding: 1.15rem 1.1rem 1.2rem; counter-increment: card; }
.cards article::before { content: "0" counter(card); position: absolute; top: .85rem; right: .9rem; color: var(--accent); font-family: var(--mono); font-size: .64rem; letter-spacing: .08em; opacity: .8; }
.cards h2 { margin: 0 0 .5rem; color: var(--ink); font-family: var(--sans); font-size: 1.08rem; letter-spacing: -.02em; font-weight: 700; }
.cards p { margin: 0; color: var(--muted); font-size: .96rem; line-height: 1.65; }

.prose { max-width: 900px; padding-bottom: 3rem; }
.prose h2 { margin: 2.1rem 0 .65rem; color: var(--ink); font-family: var(--sans); font-size: clamp(1.3rem, 2.6vw, 1.75rem); letter-spacing: -.03em; font-weight: 700; text-wrap: balance; }
.prose h2::before { content: "// "; color: var(--accent); font-family: var(--mono); font-size: .75em; letter-spacing: 0; }
.prose h3 { margin: 1.5rem 0 .4rem; color: var(--ink); font-size: 1.05rem; }
.prose p, .prose li { color: #b3c4cc; font-size: 1rem; }
.prose ul, .prose ol { padding-left: 1.25rem; }
.prose li { margin: .35rem 0; }
.prose strong { color: var(--ink); }
.prose pre { overflow-x: auto; background: #03070a; border: 1px solid var(--line); color: #c8f7e8; padding: 1rem; font-family: var(--mono); font-size: .8rem; line-height: 1.65; }
.prose code { font-family: var(--mono); font-size: .9em; }
.prose p code, .prose li code { background: rgba(83, 240, 194, .09); color: var(--accent); padding: .1rem .3rem; border: 1px solid rgba(83, 240, 194, .14); }
.prose table, .calc table { width: 100%; border-collapse: collapse; margin: 1rem 0; font-size: .95rem; background: rgba(7, 13, 18, .7); }
th, td { text-align: left; vertical-align: top; padding: .7rem .75rem; border-bottom: 1px solid var(--line); }
th { background: rgba(13, 22, 31, .9); color: var(--accent); font-family: var(--mono); font-size: .7rem; font-weight: 500; letter-spacing: .07em; text-transform: uppercase; }
td { color: #b3c4cc; }
tr:hover td { background: rgba(83, 240, 194, .025); }

.faq { max-width: 900px; padding-bottom: 3rem; }
.faq details { background: rgba(8, 16, 22, .72); border: 1px solid var(--line); padding: .85rem .95rem; margin: .55rem 0; }
.faq details[open] { border-color: var(--line-strong); }
.faq summary { cursor: pointer; color: var(--ink); font-family: var(--mono); font-size: .88rem; letter-spacing: .01em; }
.faq summary::marker { color: var(--accent); }
.faq details p { margin: .7rem 0 0; color: var(--muted); font-size: .96rem; }

.site-footer {
  width: min(1180px, calc(100% - 2rem));
  margin: 2rem auto 0;
  padding: 1.8rem 0 2rem;
  border-top: 1px solid var(--line);
  color: var(--faint);
  font-size: .82rem;
}
.footer-top { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 1.85fr); gap: 3rem; padding-bottom: 1.35rem; }
.footer-brand { max-width: 46ch; }
.footer-signature { display: flex; align-items: center; gap: .5rem; margin: 0 0 .45rem; font-family: var(--mono); font-size: 1.06rem; font-weight: 700; letter-spacing: .08em; line-height: 1.2; }
.footer-mark { display: block; width: 22px; height: 22px; flex: 0 0 22px; }
.footer-word { display: inline-flex; align-items: center; }
.footer-vane { color: var(--ink); font-weight: 750; }
.footer-cost { color: var(--accent); font-weight: 500; }
.footer-cursor { color: var(--accent); opacity: .55; margin-left: .18rem; animation: cursor-blink 2.4s steps(1) infinite; }
@keyframes cursor-blink { 0%, 55% { opacity: .55; } 56%, 100% { opacity: .12; } }
.footer-tagline { margin: .2rem 0; color: var(--muted); font-size: .82rem; line-height: 1.5; }
.footer-disclaimer { margin: .2rem 0; color: var(--faint); font-size: .78rem; line-height: 1.55; }
.footer-links { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; align-content: start; }
.footer-group { display: flex; flex-direction: column; align-items: flex-start; }
.footer-label { display: block; margin: 0 0 .45rem; color: var(--accent); font-family: var(--mono); font-size: .7rem; letter-spacing: .1em; opacity: .8; }
.footer-group a { display: flex; align-items: center; min-height: 32px; width: 100%; color: var(--muted); text-decoration: none; font-family: var(--mono); font-size: .8rem; text-transform: uppercase; padding: .2rem 0; border-bottom: 1px solid transparent; }
.footer-group a:hover { color: var(--accent); border-bottom-color: var(--line-strong); }
.footer-meta { display: flex; align-items: center; gap: .5rem; margin: 0; padding-top: .9rem; border-top: 1px solid var(--line); color: var(--faint); font-family: var(--mono); font-size: .72rem; line-height: 1.5; }
.footer-dot { width: 5px; height: 5px; flex: 0 0 auto; background: var(--accent); box-shadow: 0 0 7px rgba(83, 240, 194, .7); }
.site-footer p { margin: .3rem 0; }
.site-footer a { color: var(--muted); }
.site-footer a:hover { color: var(--accent); }

@media (max-width: 980px) {
  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .results { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .results > div { border-bottom: 1px solid var(--line); }
  .results > div:nth-child(2n) { border-right: 0; }
  .results .result-main { grid-column: 1 / -1; border-right: 0; }
  .cards { grid-template-columns: 1fr; }
}
@media (max-width: 700px) {
  .site-header { flex-wrap: nowrap; padding: .5rem .75rem; min-height: 56px; gap: .35rem; }
  .brand { gap: .4rem; font-size: .88rem; letter-spacing: .03em; flex-shrink: 0; }
  .brand-mark { width: 26px; height: 26px; font-size: .85rem; }
  .nav { order: 0; width: auto; margin-left: auto; flex-wrap: nowrap; overflow: visible; gap: 0; }
  .nav a { font-size: .86rem; padding: .4rem .2rem; letter-spacing: 0; white-space: nowrap; }
  .nav-long { display: none; }
  .nav-short { display: inline; }
  .lang { margin-left: 0; padding: .3rem .36rem; font-size: .82rem; flex-shrink: 0; }
  .lang-long { display: none; }
  .lang-short { display: inline; }
  .hero { padding-top: 1.6rem; padding-bottom: 1.25rem; }
  .hero-meta { margin-bottom: 1rem; }
  .hero-actions { align-items: stretch; }
  .btn-primary, .btn-ghost { justify-content: center; flex: 1 1 auto; }
  .grid { grid-template-columns: 1fr; padding: 0 1rem; }
  .calc-head { padding: 1rem 1rem 0; flex-direction: column; }
  .presets { width: 100%; }
  .presets button { flex: 1 1 auto; }
  .console-bar { padding: .6rem 1rem; }
  .results { grid-template-columns: 1fr; }
  .results > div { border-right: 0; }
  .results .result-main { grid-column: auto; }
  .privacy-note, .formula-box, .error, .calc > #result-note { margin-left: 1rem; margin-right: 1rem; }
  .formula-box { margin-bottom: 1rem; }
  .prose h2 { margin-top: 1.8rem; }
  .site-footer { padding: 1.5rem 0 1.8rem; }
  .footer-top { grid-template-columns: 1fr; gap: 1.3rem; padding-bottom: 1.2rem; }
  .footer-brand { max-width: none; }
  .footer-links { gap: 1.25rem; }
  .footer-group a { min-height: 36px; font-size: .82rem; }
}
@media (max-width: 360px) {
  .brand > span:last-child { display: none; }
  .site-header { padding-left: .55rem; padding-right: .55rem; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .chip-live i { animation: none; }
}