/* ==========================================================================
   MyCalculator — Design System
   Signature: results render in a monospace "readout" — like a physical
   calculator display — tying the visual language to the product itself.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@500;600;700;800&family=Inter:wght@400;500;600&family=IBM+Plex+Mono:wght@500;600&display=swap');

:root {
  /* Color */
  --ink:        #14181F;
  --ink-soft:   #4B5261;
  --muted:      #6E7686;
  --line:       #E3E6EB;
  --line-soft:  #EEF0F3;
  --bg:         #F6F7F9;
  --surface:    #FFFFFF;
  --brand:      #1F3A5F;
  --brand-dark: #142B47;
  --brand-tint: #EAF0F7;
  --accent:     #1F8A70;
  --accent-tint:#E7F5F1;
  --amber:      #B7791F;
  --danger:     #C0442C;

  /* Type */
  --font-display: 'Manrope', ui-sans-serif, system-ui, sans-serif;
  --font-body: 'Inter', ui-sans-serif, system-ui, sans-serif;
  --font-mono: 'IBM Plex Mono', ui-monospace, SFMono-Regular, monospace;

  /* Scale */
  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px rgba(20,24,31,0.04);
  --shadow: 0 4px 16px rgba(20,24,31,0.06);
  --shadow-lg: 0 12px 32px rgba(20,24,31,0.10);
  --container: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--bg);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--ink);
  line-height: 1.2;
  margin: 0 0 0.5em;
  letter-spacing: -0.01em;
}
h1 { font-size: clamp(1.9rem, 3.4vw, 2.7rem); font-weight: 800; }
h2 { font-size: clamp(1.4rem, 2.2vw, 1.9rem); font-weight: 700; }
h3 { font-size: 1.15rem; font-weight: 700; }
p { margin: 0 0 1em; color: var(--ink-soft); }

.container { max-width: var(--container); margin: 0 auto; padding: 0 20px; }
.section { padding: 56px 0; }
.section-tight { padding: 32px 0; }
.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  display: inline-block;
  margin-bottom: 10px;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 40;
  background: rgba(246,247,249,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.site-header .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--font-display); font-weight: 800; font-size: 1.15rem; color: var(--ink); }
.brand img { width: 30px; height: 30px; }
.main-nav { display: flex; align-items: center; gap: 26px; }
.main-nav a { font-size: 0.92rem; font-weight: 600; color: var(--ink-soft); }
.main-nav a:hover { color: var(--brand); }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 6px; }
.nav-toggle svg { width: 24px; height: 24px; }

@media (max-width: 860px) {
  .main-nav { position: fixed; inset: 68px 0 0 0; background: var(--surface); flex-direction: column; align-items: flex-start; padding: 24px 20px; gap: 4px; transform: translateX(100%); transition: transform .25s ease; overflow-y: auto; }
  .main-nav.open { transform: translateX(0); }
  .main-nav a { width: 100%; padding: 12px 4px; border-bottom: 1px solid var(--line-soft); }
  .nav-toggle { display: block; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: var(--font-body); font-weight: 600; font-size: 0.92rem;
  padding: 11px 20px; border-radius: var(--radius-sm); border: 1px solid transparent;
  cursor: pointer; transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-dark); }
.btn-ghost { background: transparent; border-color: var(--line); color: var(--ink); }
.btn-ghost:hover { border-color: var(--brand); color: var(--brand); }
.btn-block { width: 100%; }

/* ---------- Hero ---------- */
.hero { padding: 64px 0 40px; text-align: center; }
.hero p.lede { max-width: 640px; margin: 0 auto 28px; font-size: 1.06rem; }

/* ---------- Search ---------- */
.calc-search { max-width: 620px; margin: 0 auto; position: relative; }
.calc-search input {
  width: 100%; padding: 15px 46px 15px 18px; font-size: 1rem; font-family: var(--font-body);
  border: 1.5px solid var(--line); border-radius: var(--radius); background: var(--surface);
  box-shadow: var(--shadow-sm);
}
.calc-search input:focus { border-color: var(--brand); }
.calc-search svg { position: absolute; right: 16px; top: 50%; transform: translateY(-50%); width: 18px; height: 18px; color: var(--muted); }
.search-results {
  position: absolute; left: 0; right: 0; top: calc(100% + 8px);
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow-lg); max-height: 340px; overflow-y: auto; text-align: left; z-index: 30; display: none;
}
.search-results.active { display: block; }
.search-results a { display: block; padding: 12px 16px; border-bottom: 1px solid var(--line-soft); }
.search-results a:last-child { border-bottom: none; }
.search-results a:hover { background: var(--brand-tint); }
.search-results .r-name { font-weight: 700; font-size: 0.94rem; }
.search-results .r-meta { font-size: 0.78rem; color: var(--muted); font-family: var(--font-mono); }
.search-empty { padding: 16px; color: var(--muted); font-size: 0.9rem; }

/* ---------- Grids / Cards ---------- */
.grid { display: grid; gap: 16px; }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 900px) { .grid-4 { grid-template-columns: repeat(2, 1fr); } .grid-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; } }

.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px; box-shadow: var(--shadow-sm); transition: box-shadow .15s ease, transform .15s ease, border-color .15s ease;
}
.card-link { display: block; }
.card-link:hover .card { box-shadow: var(--shadow); border-color: #D4DAE3; transform: translateY(-2px); }
.card h3 { margin-bottom: 4px; font-size: 1rem; }
.card p { font-size: 0.88rem; margin: 0; }
.card .tag { display: inline-block; font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: .04em; text-transform: uppercase; color: var(--brand); background: var(--brand-tint); padding: 3px 8px; border-radius: 4px; margin-bottom: 10px; }

.section-head { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 22px; gap: 12px; flex-wrap: wrap; }
.section-head .view-all { font-size: 0.86rem; font-weight: 600; color: var(--brand); white-space: nowrap; }

/* ---------- Calculator layout ---------- */
.calc-page-head { padding: 40px 0 8px; }
.breadcrumbs { font-size: 0.82rem; color: var(--muted); margin-bottom: 14px; }
.breadcrumbs a { color: var(--muted); }
.breadcrumbs a:hover { color: var(--brand); }
.calc-wrap { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 24px; align-items: start; margin: 24px 0 8px; }
@media (max-width: 860px) { .calc-wrap { grid-template-columns: 1fr; } }

.calc-panel {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius-lg);
  padding: 26px; box-shadow: var(--shadow-sm);
}
.field { margin-bottom: 16px; }
.field label { display: flex; justify-content: space-between; font-size: 0.86rem; font-weight: 600; margin-bottom: 6px; color: var(--ink); }
.field .hint { font-weight: 400; color: var(--muted); font-size: 0.78rem; }
.field input[type="number"], .field input[type="text"], .field select {
  width: 100%; padding: 11px 13px; font-size: 1rem; font-family: var(--font-mono);
  border: 1.5px solid var(--line); border-radius: var(--radius-sm); background: var(--bg);
}
.field input:focus, .field select:focus { border-color: var(--brand); background: var(--surface); }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 460px) { .field-row { grid-template-columns: 1fr; } }

/* Result "readout" — the signature element */
.readout {
  background: var(--brand-dark);
  border-radius: var(--radius-lg);
  padding: 24px 22px;
  color: #fff;
  box-shadow: var(--shadow);
}
.readout .r-label { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: .08em; text-transform: uppercase; color: #9FB4CC; margin-bottom: 6px; }
.readout .r-value { font-family: var(--font-mono); font-size: 2.1rem; font-weight: 600; color: #fff; letter-spacing: -0.01em; word-break: break-word; }
.readout .r-sub { font-size: 0.84rem; color: #B9C7D8; margin-top: 4px; }
.readout-list { margin-top: 16px; padding-top: 16px; border-top: 1px solid rgba(255,255,255,0.14); display: grid; gap: 10px; }
.readout-row { display: flex; justify-content: space-between; align-items: baseline; font-size: 0.88rem; }
.readout-row .k { color: #B9C7D8; }
.readout-row .v { font-family: var(--font-mono); font-weight: 600; color: #fff; }
.readout.is-empty .r-value { color: #7C93AC; }

.calc-note { font-size: 0.82rem; color: var(--muted); margin-top: 14px; padding-top: 14px; border-top: 1px solid var(--line-soft); }

/* Article-style explainer blocks under calculators */
.explainer { max-width: 760px; }
.explainer h2 { margin-top: 2em; }
.explainer table { width: 100%; border-collapse: collapse; margin: 1em 0; font-size: 0.92rem; }
.explainer th, .explainer td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); }
.explainer th { font-family: var(--font-mono); font-size: 0.75rem; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
.explainer code { font-family: var(--font-mono); background: var(--brand-tint); padding: 1px 6px; border-radius: 4px; font-size: 0.88em; }
.callout { background: var(--accent-tint); border: 1px solid #CFE9E0; border-radius: var(--radius); padding: 14px 16px; font-size: 0.9rem; color: #135641; margin: 1.2em 0; }
.callout strong { color: #0E4433; }

.faq details { border-bottom: 1px solid var(--line); padding: 14px 0; }
.faq summary { cursor: pointer; font-weight: 700; font-size: 0.98rem; list-style: none; display: flex; justify-content: space-between; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font-family: var(--font-mono); color: var(--brand); font-weight: 400; }
.faq details[open] summary::after { content: "–"; }
.faq details p { margin-top: 10px; }

.related { margin-top: 40px; }

/* ---------- Category chips ---------- */
.chip-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0 30px; }
.chip { font-size: 0.82rem; font-weight: 600; padding: 7px 13px; border-radius: 999px; border: 1px solid var(--line); background: var(--surface); color: var(--ink-soft); }
.chip.active, .chip:hover { border-color: var(--brand); color: var(--brand); background: var(--brand-tint); }

/* ---------- Why / How sections ---------- */
.icon-tile { width: 40px; height: 40px; border-radius: 10px; background: var(--brand-tint); display: flex; align-items: center; justify-content: center; margin-bottom: 12px; color: var(--brand); }
.icon-tile svg { width: 20px; height: 20px; }

/* ---------- Footer ---------- */
.site-footer { background: var(--brand-dark); color: #C8D3E0; padding: 48px 0 26px; margin-top: 64px; }
.site-footer a { color: #C8D3E0; }
.site-footer a:hover { color: #fff; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 28px; margin-bottom: 32px; }
@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
.footer-grid h4 { color: #fff; font-size: 0.82rem; text-transform: uppercase; letter-spacing: .06em; font-family: var(--font-mono); margin-bottom: 14px; }
.footer-grid ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 9px; font-size: 0.88rem; }
.footer-brand { display: flex; align-items: center; gap: 9px; font-family: var(--font-display); font-weight: 800; color: #fff; font-size: 1.1rem; margin-bottom: 10px; }
.footer-brand img { width: 26px; height: 26px; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.12); padding-top: 20px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px; font-size: 0.8rem; color: #93A3B8; }
.disclaimer-box { font-size: 0.78rem; color: #93A3B8; max-width: 760px; margin-top: 14px; line-height: 1.6; }

/* ---------- Utility ---------- */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.skip-link { position: absolute; left: -999px; top: 0; background: var(--brand); color: #fff; padding: 10px 16px; z-index: 100; }
.skip-link:focus { left: 10px; top: 10px; }