/* Layout: single reading column; each calculator is a "meter panel" with a mono readout strip. */
:root {
  --bg: #eef1f3;          /* cool galvanized grey */
  --surface: #ffffff;
  --ink: #14202b;         /* deep slate */
  --muted: #56636f;
  --line: #cdd5db;
  --copper: #a8521f;      /* bare copper wire */
  --copper-soft: #f4e3d6;
  --readout-bg: #14202b;
  --readout-ink: #f2c68b; /* warm meter glow */
  --pos: #c2352b;         /* + terminal red, used sparingly */
  --font-display: "Barlow Semi Condensed", "Arial Narrow", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Public Sans", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-data: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --measure: 68ch;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f161d; --surface: #17212b; --ink: #e4e9ee; --muted: #9aa7b3; --line: #2b3a47;
    --copper: #e08a52; --copper-soft: #2e2219; --readout-bg: #070b0f; --readout-ink: #f5c98f; --pos: #ef6b5f;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f161d; --surface: #17212b; --ink: #e4e9ee; --muted: #9aa7b3; --line: #2b3a47;
  --copper: #e08a52; --copper-soft: #2e2219; --readout-bg: #070b0f; --readout-ink: #f5c98f; --pos: #ef6b5f;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font: 400 1.0625rem/1.65 var(--font-body);
}
a { color: var(--copper); text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--copper); outline-offset: 2px; }

.wrap {
  max-width: 860px; margin: 0 auto;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
}

/* Header */
.site-head { border-bottom: 1px solid var(--line); background: var(--surface); }
.site-head .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px 24px; padding-block: 14px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); font: 700 1.35rem/1 var(--font-display); letter-spacing: 0.01em; }
.brand svg { flex: none; }
.nav { display: flex; flex-wrap: wrap; gap: 4px 18px; font: 600 0.95rem/1.2 var(--font-display); text-transform: uppercase; letter-spacing: 0.06em; }
.nav a { color: var(--muted); text-decoration: none; padding-block: 4px; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--ink); box-shadow: inset 0 -2px 0 var(--copper); }

/* Type */
main { padding-block: 32px 56px; }
h1, h2, h3 { font-family: var(--font-display); line-height: 1.1; text-wrap: balance; }
h1 { font-size: clamp(2.1rem, 5vw, 3.1rem); font-weight: 700; margin: 0 0 12px; letter-spacing: -0.005em; }
h2 { font-size: 1.75rem; font-weight: 700; margin: 2.2em 0 0.5em; }
h3 { font-size: 1.25rem; font-weight: 600; margin: 1.6em 0 0.4em; }
p, ul, ol { max-width: var(--measure); }
.lede { font-size: 1.2rem; color: var(--muted); margin: 0 0 28px; }
.eyebrow { font: 600 0.8rem/1 var(--font-display); text-transform: uppercase; letter-spacing: 0.12em; color: var(--copper); margin: 0 0 10px; }
.num, .data { font-family: var(--font-data); font-variant-numeric: tabular-nums; }
code { font-family: var(--font-data); font-size: 0.92em; background: var(--copper-soft); padding: 1px 5px; border-radius: 3px; }

/* Calculator panel */
.calc { background: var(--surface); border: 1px solid var(--line); border-radius: 6px; overflow: hidden; }
.calc-inputs { padding: 22px; display: grid; gap: 18px; }
.fields { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 16px; }
.field { display: grid; gap: 6px; min-width: 0; align-content: start; }
.field label, .lbl { font: 600 0.8rem/1.2 var(--font-display); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); }
.field small { color: var(--muted); font-size: 0.82rem; line-height: 1.4; }
input, select {
  font: 500 1rem/1.2 var(--font-data); color: var(--ink); background: var(--bg);
  border: 1px solid var(--line); border-radius: 4px; padding: 10px 11px; width: 100%; min-width: 0;
}
input:focus, select:focus { border-color: var(--copper); outline: none; box-shadow: 0 0 0 3px var(--copper-soft); }

.table-scroll { overflow-x: auto; margin: 0 -4px; }
.loads { width: 100%; border-collapse: collapse; min-width: 640px; }
.loads th { text-align: left; font: 600 0.75rem/1.2 var(--font-display); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); padding: 0 4px 8px; }
.loads td { padding: 4px; vertical-align: middle; }
.loads td:nth-child(1) { width: 30%; }
.loads input, .loads select { padding: 8px; font-size: 0.95rem; }
/* Keep the DC/AC dropdown wide enough to show its value plus the arrow */
.loads td:nth-child(5), .loads th:nth-child(5) { width: 7rem; min-width: 7rem; }
.loads select.ac { min-width: 6.5rem; padding-right: 28px; }
.loads input.t { font-family: var(--font-body); }
.loads .whcell { text-align: right; color: var(--muted); white-space: nowrap; padding-right: 8px; }
.rm { background: none; border: 1px solid transparent; color: var(--muted); font-size: 1.3rem; line-height: 1; padding: 4px 9px; border-radius: 4px; cursor: pointer; }
.rm:hover { color: var(--pos); border-color: var(--line); }
.btn { font: 600 0.9rem/1 var(--font-display); text-transform: uppercase; letter-spacing: 0.08em; background: none; color: var(--copper); border: 1.5px solid var(--copper); border-radius: 4px; padding: 10px 14px; cursor: pointer; justify-self: start; }
.btn:hover { background: var(--copper-soft); }
.example-note { font-size: 0.85rem; color: var(--muted); margin: 0; }

/* Readout strip */
.readout { background: var(--readout-bg); color: #c9d3dc; padding: 22px; display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 18px 24px; }
.readout .lbl { color: #8c9aa7; display: block; margin-bottom: 6px; }
.readout .val { font: 500 1.9rem/1 var(--font-data); font-variant-numeric: tabular-nums; color: var(--readout-ink); }
.readout .unit { font: 500 0.95rem/1 var(--font-data); color: #8c9aa7; margin-left: 4px; }
.readout .primary .val { font-size: 2.6rem; }
.readout-foot { grid-column: 1 / -1; font-size: 0.88rem; color: #9fb0bd; margin: 0; border-top: 1px solid #2a3846; padding-top: 14px; max-width: none; }
.readout-foot a { color: var(--readout-ink); }

/* Product picks */
.picks-head { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: baseline; gap: 6px 16px; margin: 36px 0 12px; }
.picks-head h2 { margin: 0; }
.picks-head p { margin: 0; font-size: 0.82rem; color: var(--muted); }
.picks { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; }
.pick { display: grid; gap: 6px; align-content: start; text-decoration: none; color: var(--ink); background: var(--surface); border: 1px solid var(--line); border-radius: 6px; padding: 16px; transition: border-color .15s; }
.pick:hover { border-color: var(--copper); }
.pick-kind { font: 600 0.72rem/1 var(--font-display); text-transform: uppercase; letter-spacing: 0.12em; color: var(--copper); }
.pick-name { font: 600 1.1rem/1.25 var(--font-display); }
.pick-why { font-size: 0.9rem; color: var(--muted); line-height: 1.45; }
.pick-go { font: 600 0.85rem/1 var(--font-display); color: var(--copper); margin-top: 4px; }

/* Content */
.content { margin-top: 8px; }
.ref { overflow-x: auto; }
.ref table { border-collapse: collapse; min-width: 420px; width: 100%; max-width: var(--measure); font-size: 0.95rem; }
.ref th, .ref td { text-align: left; padding: 8px 12px 8px 0; border-bottom: 1px solid var(--line); }
.ref th { font: 600 0.78rem/1.2 var(--font-display); text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); }
.ref td.n { font-family: var(--font-data); font-variant-numeric: tabular-nums; }
.formula { font-family: var(--font-data); background: var(--surface); border: 1px solid var(--line); border-left: 3px solid var(--copper); padding: 12px 14px; border-radius: 0 4px 4px 0; max-width: var(--measure); overflow-x: auto; font-size: 0.95rem; }
.faq details { border-bottom: 1px solid var(--line); padding-block: 12px; max-width: var(--measure); }
.faq summary { cursor: pointer; font: 600 1.15rem/1.3 var(--font-display); }
.faq details p { margin: 10px 0 2px; }
.callout { background: var(--copper-soft); border-radius: 4px; padding: 12px 16px; max-width: var(--measure); font-size: 0.95rem; }

/* Home */
.tools { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 14px; margin-top: 8px; }
.tool { display: grid; gap: 8px; align-content: start; text-decoration: none; color: var(--ink); background: var(--surface); border: 1px solid var(--line); border-radius: 6px; padding: 20px; }
.tool:hover { border-color: var(--copper); }
.tool .unitmark { font: 500 1.6rem/1 var(--font-data); color: var(--copper); }
.tool h2 { font-size: 1.4rem; margin: 0; }
.tool p { margin: 0; color: var(--muted); font-size: 0.95rem; }
.steps { padding-left: 1.2em; }
.steps li { margin-bottom: 6px; }

.ad-slot { margin: 32px 0; min-height: 90px; }

/* Footer */
.site-foot { border-top: 1px solid var(--line); background: var(--surface); font-size: 0.88rem; color: var(--muted); }
.site-foot .wrap { padding-block: 24px 32px; display: grid; gap: 10px; }
.site-foot nav { display: flex; flex-wrap: wrap; gap: 6px 18px; }
.site-foot a { color: var(--muted); }
.site-foot p { margin: 0; max-width: none; }

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

/* Glossary tooltips */
.label-row { display: flex; align-items: center; gap: 6px; }
abbr.tip { text-decoration: none; border-bottom: 1px dotted currentColor; cursor: help; }
abbr.tip:hover { border-bottom-style: solid; }
.tip-btn {
  flex: none; width: 18px; height: 18px; padding: 0; border-radius: 50%;
  border: 1px solid var(--line); background: none; color: var(--muted);
  font: 600 0.7rem/1 var(--font-display); cursor: help;
  display: inline-grid; place-items: center;
}
.tip-btn:hover, .tip-btn:focus-visible { border-color: var(--copper); color: var(--copper); }
#vb-tip {
  position: fixed; z-index: 50; max-width: min(290px, calc(100vw - 16px));
  background: var(--ink); color: var(--bg); border: 1px solid var(--copper);
  font: 400 0.85rem/1.45 var(--font-body); padding: 9px 11px; border-radius: 5px;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.25); pointer-events: none;
}

/* Follow-on link under a result: own line, arrow never orphaned */
.readout-foot .next-step { display: block; width: fit-content; max-width: 100%; margin-top: 8px; font-weight: 600; }