/* ========================================================================
   VoltDrop — theme tokens
   "Power tool" aesthetic: black tool-housing chrome, safety-orange
   controls, hazard-stripe accent. Committed dark theme (it's a device,
   not a document). Numbers: bold system type, tabular digits — no LCD
   gimmick fonts.
   ======================================================================== */
:root {
  --color-bg: #141518;         /* tool housing */
  --color-surface: #1f2125;    /* panel face */
  --color-surface-2: #26282d;  /* recessed wells */
  --color-ink: #f4f5f6;        /* white text: 14.9:1 on surface */
  --color-ink-soft: #b0b5bb;   /* hints: 7.5:1 on surface */
  --color-line: #3a3d43;
  --color-line-strong: #4d5158;

  --color-accent: #ff7a1a;     /* safety orange */
  --color-accent-hot: #ff8c39;
  --color-accent-ink: #1c1002; /* near-black on orange: 9.6:1 */
  --color-hazard: #ffc814;     /* hazard yellow */

  --verdict-good-bg: #16311f;
  --verdict-good-ink: #9fe0b3;   /* 8.9:1 on its bg */
  --verdict-good-bar: #3dbb68;
  --verdict-warn-bg: #362a08;
  --verdict-warn-ink: #ffd24d;   /* 9.5:1 on its bg */
  --verdict-warn-bar: #ffc814;
  --verdict-bad-bg: #3a1515;
  --verdict-bad-ink: #ffabab;    /* 8.3:1 on its bg */
  --verdict-bad-bar: #ff5252;

  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;

  --radius: 12px;
  --radius-sm: 8px;

  --hazard-stripe: repeating-linear-gradient(
    -45deg,
    var(--color-hazard) 0 12px,
    #141518 12px 24px
  );
}

/* ========================================================================
   Base
   ======================================================================== */
* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

[hidden] { display: none !important; }

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.55;
  color: var(--color-ink);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* Big clear numbers everywhere numbers appear */
input, select, .big-number, .result-cell .v {
  font-variant-numeric: lining-nums tabular-nums;
}

.wrap {
  max-width: 620px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

/* ========================================================================
   Header — nameplate with hazard stripe
   ======================================================================== */
.site-header {
  padding: var(--space-5) 0 var(--space-4);
  background: var(--color-surface);
  border-bottom: 6px solid transparent;
  border-image: var(--hazard-stripe) 1;
}

.brand-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

/* Mobile header (pitchchanger-style): Tools | VOLTDROP | Feedback, chip on row 2 */
.tools-btn, .header-feedback {
  display: none;
  font-family: inherit;
  font-size: 13px;
  font-weight: 750;
  color: var(--color-ink);
  background: var(--color-surface-2);
  border: 2px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: var(--space-1) var(--space-3);
  min-height: 38px;
  cursor: pointer;
  text-decoration: none;
  align-items: center;
  white-space: nowrap;
}

.tools-btn:hover, .header-feedback:hover { border-color: var(--color-accent); }
.tools-btn:focus-visible, .header-feedback:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.tools-btn:active, .header-feedback:active { transform: translateY(1px); }
.tools-btn[aria-expanded="true"] { border-color: var(--color-accent); color: var(--color-accent); }

.mobile-tools {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-top: var(--space-3);
  padding: var(--space-2);
  background: var(--color-surface-2);
  border: 1.5px solid var(--color-line);
  border-radius: var(--radius);
}

.mobile-tools .tool-link {
  min-height: 48px;
  padding: var(--space-3);
  font-size: 15px;
}

@media (max-width: 1023px) {
  /* Row 1: Tools · country · Feedback. Row 2: centered brand. Row 3: tagline. */
  .brand-row { flex-wrap: wrap; justify-content: space-between; }
  .tools-btn { display: inline-flex; order: 1; font-size: 14px; min-height: 44px; padding: var(--space-2) var(--space-3); }
  .country-chip { order: 2; }
  .header-feedback { display: inline-flex; order: 3; font-size: 14px; min-height: 44px; padding: var(--space-2) var(--space-3); }
  .brand {
    order: 4;
    flex-basis: 100%;
    justify-content: center;
    align-items: center;
    font-size: 22px;
    line-height: 1;
    margin: var(--space-4) 0 var(--space-1);
  }
  .brand-logo { width: 26px; height: 26px; }
  .tagline { text-align: center; }
  /* keep content clear of the hazard stripe */
  .main-col > :first-child { margin-top: var(--space-5); }
}

@media (min-width: 1024px) {
  .mobile-tools { display: none !important; }
  /* Desktop header: same stacked structure as mobile — controls top-right,
     brand centered on its own line, tagline centered. */
  .site-header .wrap, .site-footer .wrap { max-width: 860px; }
  .brand-row { flex-wrap: wrap; justify-content: flex-end; }
  .header-feedback { display: inline-flex; order: 1; min-height: 44px; }
  .country-chip { order: 2; }
  .brand {
    order: 3;
    flex-basis: 100%;
    justify-content: center;
    font-size: 28px;
    line-height: 1;
    margin: var(--space-3) 0 var(--space-1);
  }
  .tagline { text-align: center; }
}

.country-chip {
  font-family: inherit;
  font-size: 14px;
  font-weight: 750;
  color: var(--color-ink);
  background: var(--color-surface-2);
  border: 2px solid var(--color-line);
  border-radius: var(--radius-sm); /* same rectangle style as Tools/Feedback */
  padding: var(--space-2) var(--space-3);
  min-height: 44px;
  cursor: pointer;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
}

.country-chip:hover { border-color: var(--color-accent); }
.country-chip:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.country-chip:active { transform: translateY(1px); }

.country-picker {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-line);
}

.country-label {
  font-size: 12.5px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-ink-soft);
}

.country-btn {
  font-family: inherit;
  font-size: 13.5px;
  font-weight: 700;
  color: var(--color-ink);
  background: var(--color-surface-2);
  border: 2px solid var(--color-line);
  border-radius: 999px;
  padding: var(--space-1) var(--space-3);
  min-height: 38px;
  cursor: pointer;
}

.country-btn:hover { border-color: var(--color-accent); }
.country-btn:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.country-btn:active { transform: translateY(1px); }

.country-btn.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

.country-note {
  flex-basis: 100%;
  font-size: 12px;
  color: var(--color-ink-soft);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 26px;
  font-weight: 800;
  letter-spacing: 0.01em;
  text-transform: uppercase;
}

.brand { text-decoration: none; }
.brand:hover .brand-name { color: var(--color-accent); }
.brand:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 3px; border-radius: var(--radius-sm); }
.brand-name { color: var(--color-ink); }
.brand-logo { display: block; width: 30px; height: 30px; }

.tagline {
  margin: var(--space-1) 0 0;
  color: var(--color-ink-soft);
  font-size: 15px;
}

/* ========================================================================
   Layout — left tool sidebar on desktop (pitchchanger-style), hidden on
   mobile where the mode tabs take over
   ======================================================================== */
.layout { display: block; }
.sidebar { display: none; }

@media (min-width: 1024px) {
  .layout {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--space-6);
    max-width: 860px;
  }
  .sidebar { display: block; padding-top: var(--space-5); }
  .tool-nav { position: sticky; top: var(--space-5); display: flex; flex-direction: column; gap: 2px; }
  /* sidebar is the tool switcher on desktop; !important because the
     .mode-tabs base rule appears later in the file and would win otherwise */
  .mode-tabs { display: none !important; }
  .main-col { padding-top: var(--space-5); }
}

.tool-nav-head {
  font-size: 11.5px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-ink-soft);
  margin-bottom: var(--space-2);
}

.tool-link {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  font-size: 14px;
  font-weight: 650;
  color: var(--color-ink);
  text-decoration: none;
  border-radius: var(--radius-sm);
  border: 2px solid transparent;
}

.tool-link:hover { background: var(--color-surface-2); border-color: var(--color-line); }
.tool-link:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.tool-link:active { transform: translateY(1px); }

.tool-link.active {
  background: var(--color-surface-2);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.tool-sep {
  border: none;
  border-top: 1.5px solid var(--color-line);
  margin: var(--space-3) var(--space-2);
}

.tool-link.soon {
  color: var(--color-ink-soft);
  cursor: default;
}
.tool-link.soon:hover { background: none; border-color: transparent; }
.tool-link.soon:active { transform: none; }
.tool-link.soon em {
  font-style: normal;
  font-size: 10.5px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-hazard);
  border: 1.5px solid var(--color-hazard);
  border-radius: 999px;
  padding: 0 6px;
  margin-left: auto;
}

/* ========================================================================
   Mode tabs — like a tool's function selector
   ======================================================================== */
.mode-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-2);
  margin: var(--space-5) 0 var(--space-4);
}

.mode-tab {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: var(--space-3);
  background: var(--color-surface);
  border: 2px solid var(--color-line);
  border-radius: var(--radius);
  font-family: inherit;
  text-align: left;
  cursor: pointer;
  color: var(--color-ink);
}

.mode-tab:hover { border-color: var(--color-accent); }
.mode-tab:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.mode-tab:active { transform: translateY(1px); }

.mode-tab.active {
  border-color: var(--color-accent);
  background: var(--color-surface-2);
  box-shadow: inset 0 0 0 1px var(--color-accent);
}

.mode-tab.active .mode-title { color: var(--color-accent); }

.mode-title {
  font-weight: 750;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.mode-sub { font-size: 12.5px; color: var(--color-ink-soft); line-height: 1.35; }

/* ========================================================================
   Cards & fields
   ======================================================================== */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: var(--space-5);
  margin-bottom: var(--space-5);
}

.field { margin-bottom: var(--space-5); }
.field:last-of-type { margin-bottom: var(--space-4); }

.field-label {
  display: block;
  font-weight: 750;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-ink);
  margin-bottom: var(--space-2);
}

.hint {
  margin: var(--space-2) 0 0;
  font-size: 13.5px;
  color: var(--color-ink-soft);
  line-height: 1.45;
}

.highlight-hint strong { color: var(--color-hazard); }

/* Segmented controls — chunky tool switches */
.seg {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.seg-btn {
  flex: 1 1 auto;
  min-height: 46px;
  padding: var(--space-2) var(--space-3);
  font-family: inherit;
  font-size: 14.5px;
  font-weight: 600;
  color: var(--color-ink);
  background: var(--color-surface-2);
  border: 2px solid var(--color-line);
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.seg-btn:hover { border-color: var(--color-accent); }
.seg-btn:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.seg-btn:active { transform: translateY(1px); }

.seg-btn.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
  font-weight: 750;
}

/* Inputs — recessed wells, big clear digits */
.input-unit {
  display: flex;
  align-items: stretch;
}

.input-unit input {
  flex: 1;
  min-width: 0;
  min-height: 52px;
  padding: var(--space-2) var(--space-3);
  font-family: inherit;
  font-size: 22px;
  font-weight: 700;
  color: var(--color-ink);
  background: var(--color-bg);
  border: 2px solid var(--color-line-strong);
  border-radius: var(--radius-sm) 0 0 var(--radius-sm);
  border-right: none;
}

.input-unit input::placeholder { color: #7a8087; font-weight: 500; }

.input-unit input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: inset 0 0 0 1px var(--color-accent);
}

.input-unit .unit {
  display: flex;
  align-items: center;
  padding: 0 var(--space-3);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-ink-soft);
  background: var(--color-surface-2);
  border: 2px solid var(--color-line-strong);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

select {
  width: 100%;
  min-height: 52px;
  padding: var(--space-2) var(--space-3);
  font-family: inherit;
  font-size: 18px;
  font-weight: 700;
  color: var(--color-ink);
  background: var(--color-bg);
  border: 2px solid var(--color-line-strong);
  border-radius: var(--radius-sm);
}

select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: inset 0 0 0 1px var(--color-accent);
}

/* Voltage presets */
.preset-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-2);
}

.preset-btn {
  min-height: 38px;
  padding: 2px var(--space-3);
  font-family: inherit;
  font-size: 14px;
  font-weight: 700;
  color: var(--color-ink);
  background: var(--color-surface-2);
  border: 2px solid var(--color-line);
  border-radius: 999px;
  cursor: pointer;
}

.preset-btn:hover { border-color: var(--color-accent); }
.preset-btn:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }
.preset-btn:active { transform: translateY(1px); }

.preset-btn.active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-ink);
}

/* Calculate button — the trigger */
.calc-btn {
  width: 100%;
  min-height: 56px;
  font-family: inherit;
  font-size: 17px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-accent-ink);
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  box-shadow: 0 3px 0 #b34f05;
}

.calc-btn:hover { background: var(--color-accent-hot); }
.calc-btn:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 3px; }
.calc-btn:active { transform: translateY(2px); box-shadow: 0 1px 0 #b34f05; }
.calc-btn:disabled { opacity: 0.5; cursor: not-allowed; box-shadow: none; }

/* ========================================================================
   Results — the verdict meter (the memorable bit)
   ======================================================================== */
.results { padding: 0; overflow: hidden; border-width: 2px; }

.verdict {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-5);
  border-left: 8px solid transparent;
}

.verdict.good { background: var(--verdict-good-bg); color: var(--verdict-good-ink); border-left-color: var(--verdict-good-bar); }
.verdict.warn { background: var(--verdict-warn-bg); color: var(--verdict-warn-ink); border-left-color: var(--verdict-warn-bar); }
.verdict.bad  { background: var(--verdict-bad-bg);  color: var(--verdict-bad-ink);  border-left-color: var(--verdict-bad-bar); }

.verdict-badge {
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-3);
  border-radius: 6px;
  border: 2.5px solid currentColor;
  white-space: nowrap;
}

.big-number {
  font-size: 48px;
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.01em;
}

.big-label { font-size: 14.5px; font-weight: 600; margin-top: 2px; }

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1px;
  background: var(--color-line);
  border-top: 1px solid var(--color-line);
}

.result-cell {
  background: var(--color-surface);
  padding: var(--space-3) var(--space-4);
}

.result-cell .k {
  font-size: 11.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-ink-soft);
}
.result-cell .v { font-size: 18px; font-weight: 750; }

.verdict-note {
  margin: 0;
  padding: var(--space-3) var(--space-5);
  font-size: 14px;
  color: var(--color-ink-soft);
  border-top: 1px solid var(--color-line);
}

/* "How we calculated this" */
.math-details {
  border-top: 1px solid var(--color-line);
}

.math-details summary {
  padding: var(--space-3) var(--space-5);
  font-weight: 750;
  font-size: 13.5px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  color: var(--color-accent);
}

.math-details summary:hover { color: var(--color-accent-hot); text-decoration: underline; }
.math-details summary:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: -3px; }

.math-body {
  padding: 0 var(--space-5) var(--space-4);
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-ink);
}

.math-body .formula {
  font-size: 14px;
  font-weight: 650;
  background: var(--color-bg);
  border: 1px solid var(--color-line-strong);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-sm);
  padding: var(--space-3);
  margin: var(--space-2) 0;
  white-space: pre-wrap;       /* wrap long formulas — never hide math off-screen */
  overflow-wrap: break-word;
  font-variant-numeric: lining-nums tabular-nums;
}

/* Tool pages (ampacity, conduit) */
.tool-intro { padding: var(--space-4) var(--space-5); }
.tool-title { margin: 0 0 var(--space-1); font-size: 22px; font-weight: 800; letter-spacing: 0.01em; }
.tool-sub { margin: 0; font-size: 14.5px; color: var(--color-ink-soft); }
.inline-link { color: var(--color-accent); font-weight: 650; }
.inline-link:hover { color: var(--color-accent-hot); }
.inline-link:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }

/* ========================================================================
   Explainer & footer
   ======================================================================== */
.explainer h2 {
  font-size: 15px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin: 0 0 var(--space-2);
  color: var(--color-hazard);
}
.explainer h2 + p { margin-top: 0; }
.explainer p { font-size: 14.5px; color: var(--color-ink); margin: 0 0 var(--space-4); }
.explainer p:last-child { margin-bottom: 0; }
.explainer strong { color: var(--color-hazard); }

.site-footer {
  border-top: 6px solid transparent;
  border-image: var(--hazard-stripe) 1;
  padding: var(--space-5) 0 var(--space-6);
  background: var(--color-surface);
}

.site-footer p { margin: 0 0 var(--space-2); font-size: 14px; }

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
  margin-bottom: var(--space-4);
}

.footer-link {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-ink);
  text-decoration: none;
  padding: var(--space-1) 0;
}

.footer-link:hover { color: var(--color-accent); }
.footer-link:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }

.footer-brand { color: var(--color-ink-soft); }
.footer-brand strong { color: var(--color-ink); }
.footer-brand-link { text-decoration: none; }
.footer-brand-link:hover strong { color: var(--color-accent); }
.footer-brand-link:focus-visible { outline: 3px solid var(--color-hazard); outline-offset: 2px; }

.site-footer .fine {
  font-size: 12.5px;
  color: var(--color-ink-soft);
  line-height: 1.5;
  border-top: 1px solid var(--color-line);
  padding-top: var(--space-3);
  margin-top: var(--space-3);
  margin-bottom: 0;
}

/* Desktop footer: spread out — brand+links left/right on one row,
   country picker on the next, fine print full-width below */
@media (min-width: 1024px) {
  .site-footer .wrap {
    display: grid;
    grid-template-columns: 1fr auto;
    grid-template-areas:
      "brand links"
      "country country"
      "fine fine";
    align-items: center;
    column-gap: var(--space-6);
  }
  .footer-brand { grid-area: brand; margin: 0; }
  .footer-links { grid-area: links; margin: 0; justify-content: flex-end; }
  .country-picker {
    grid-area: country;
    border-bottom: none;
    border-top: 1px solid var(--color-line);
    padding: var(--space-3) 0 0;
    margin: var(--space-3) 0 0;
  }
  .country-note { flex-basis: auto; margin-left: auto; }
  .site-footer .fine { grid-area: fine; }
}

/* ========================================================================
   Mobile
   ======================================================================== */
@media (max-width: 480px) {
  .mode-tabs { grid-template-columns: 1fr; }
  .card { padding: var(--space-4); }
  .verdict { padding: var(--space-4); flex-wrap: wrap; }
  .big-number { font-size: 40px; }
}