/* ===== PHYSICS FUNDAMENTALS — CALCULATOR SUITE STYLES ===== */
/* Shares the site design tokens (midnight blue + brass gold). */

:root {
  --ink: #0A1628;
  --ink-2: #142139;
  --ink-3: #1F2E47;
  --cream: #FAF6EE;
  --paper: #F5F2EA;
  --gold: #C8932A;
  --gold-bright: #E8B43D;
  --gold-soft: #F4E8D0;
  --gold-text: #7E5B11;
  --bronze: #8B6914;
  --wine: #7A1F2B;
  --mist: #C5D0DC;
  --mist-2: #8597AF;
  --mist-text: #5A6D85;
  --rule: #D9CFB8;
  --shadow: 0 30px 60px rgba(10, 22, 40, 0.12);
  --shadow-deep: 0 40px 80px rgba(10, 22, 40, 0.25);
}

/* ===== THE CALCULATOR WIDGET ===== */
.pfc {
  background: var(--ink);
  border-radius: 6px;
  box-shadow: var(--shadow-deep);
  padding: 28px;
  color: var(--cream);
  margin: 0 0 40px;
}
.pfc-solvefor {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 24px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--ink-3);
}
.pfc-solvefor label {
  font-family: 'Manrope', sans-serif;
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--mist);
}
.pfc select,
.pfc input[type="number"] {
  font-family: 'Manrope', sans-serif;
  background: var(--ink-2);
  color: var(--cream);
  border: 1px solid var(--ink-3);
  border-radius: 3px;
  padding: 10px 12px;
  font-size: 15px;
  outline: none;
  transition: border-color 0.15s;
}
.pfc select:focus,
.pfc input[type="number"]:focus { border-color: var(--gold); }
.pfc-solvefor select { flex: 1; color: var(--gold); font-weight: 600; }

.pfc-inputs { display: flex; flex-direction: column; gap: 18px; }
.pfc-row { display: grid; grid-template-columns: 1fr; gap: 8px; }
.pfc-row > label {
  font-size: 13px;
  font-weight: 600;
  color: var(--mist);
  display: flex;
  align-items: baseline;
  gap: 8px;
}
.pfc-sym {
  font-family: 'JetBrains Mono', monospace;
  color: var(--gold);
  font-size: 12px;
}
.pfc-controls { display: flex; gap: 10px; }
.pfc-controls input { flex: 1; min-width: 0; }
.pfc-unit { min-width: 90px; }
.pfc-preset { margin-top: 2px; }
.pfc-unitstatic {
  display: inline-flex;
  align-items: center;
  padding: 0 12px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  color: var(--mist-2);
  background: var(--ink-2);
  border: 1px solid var(--ink-3);
  border-radius: 3px;
}

/* ===== RESULT ===== */
.pfc-result {
  margin-top: 26px;
  padding-top: 24px;
  border-top: 1px solid var(--ink-3);
}
.pfc-result--empty p { color: var(--mist-2); font-style: italic; margin: 0; font-size: 14px; }
.pfc-result-main { display: flex; flex-direction: column; gap: 4px; }
.pfc-result-label {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--mist-2);
}
.pfc-result-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 38px;
  font-weight: 500;
  color: var(--gold);
  line-height: 1.1;
}
.pfc-result-unit { font-size: 18px; color: var(--mist); }

.pfc-extras {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}
.pfc-extra {
  background: var(--ink-2);
  border: 1px solid var(--ink-3);
  border-radius: 3px;
  padding: 8px 14px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.pfc-extra span {
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--mist-2);
}
.pfc-extra strong { font-family: 'JetBrains Mono', monospace; color: var(--cream); font-size: 16px; }

.pfc-steps { margin-top: 20px; }
.pfc-steps summary {
  cursor: pointer;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--gold);
  list-style: none;
}
.pfc-steps summary::-webkit-details-marker { display: none; }
.pfc-steps summary::before { content: '▸ '; }
.pfc-steps[open] summary::before { content: '▾ '; }
.pfc-steps ol {
  margin: 14px 0 0;
  padding: 0 0 0 8px;
  list-style: none;
  counter-reset: step;
}
.pfc-steps li {
  font-family: 'JetBrains Mono', monospace;
  font-size: 14px;
  color: var(--mist);
  padding: 8px 0 8px 34px;
  position: relative;
  border-left: 1px solid var(--ink-3);
  margin-left: 10px;
}
.pfc-steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: -11px;
  top: 8px;
  width: 20px;
  height: 20px;
  background: var(--ink-2);
  border: 1px solid var(--gold);
  border-radius: 50%;
  color: var(--gold);
  font-size: 10px;
  font-family: 'Manrope', sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===== VISUALISATION ===== */
.pfc-viz { margin-top: 22px; }
.pfc-viz canvas {
  width: 100%;
  height: auto;
  background: #050D1A;
  border-radius: 4px;
  border: 1px solid var(--ink-3);
}

/* ===== CALCULATOR PAGE LAYOUT ===== */
.calc-formula {
  background: var(--ink);
  color: var(--gold);
  font-family: 'JetBrains Mono', monospace;
  font-size: 22px;
  text-align: center;
  padding: 28px 24px;
  border-radius: 4px;
  margin: 0 0 36px;
  position: relative;
  box-shadow: var(--shadow);
}
.calc-formula::before {
  content: 'FORMULA';
  position: absolute;
  top: 10px; left: 16px;
  font-size: 9px;
  letter-spacing: 0.2em;
  color: var(--mist-2);
  font-family: 'Manrope', sans-serif;
}
.calc-formula small {
  display: block;
  margin-top: 10px;
  font-size: 14px;
  color: var(--mist);
}

/* Calculator hub grid */
.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 22px;
}
.calc-card {
  background: var(--cream);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  transition: all 0.2s;
}
.calc-card:hover { border-color: var(--gold); box-shadow: var(--shadow); transform: translateY(-3px); }
.calc-card .calc-topic {
  font-size: 11px; letter-spacing: 0.12em; text-transform: uppercase;
  font-weight: 700; color: var(--gold-text); margin-bottom: 8px;
}
.calc-card h3 { font-size: 20px; margin: 0 0 8px; }
.calc-card .calc-eq {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px; color: var(--mist-text);
  background: var(--paper); padding: 6px 10px; border-radius: 3px;
  margin-bottom: 12px; display: inline-block;
}
.calc-card p { font-size: 14px; color: var(--ink-3); margin: 0 0 16px; flex: 1; line-height: 1.5; }
.calc-card .calc-link {
  font-size: 12px; letter-spacing: 0.1em; text-transform: uppercase;
  font-weight: 700; color: var(--gold-text);
}
.calc-card.is-soon { opacity: 0.62; }
.calc-card.is-soon:hover { transform: none; border-color: var(--rule); box-shadow: none; }
.calc-card .calc-soon-tag {
  align-self: flex-start;
  font-size: 10px; letter-spacing: 0.12em; text-transform: uppercase;
  font-weight: 700; color: var(--mist-text);
  border: 1px solid var(--rule); border-radius: 999px; padding: 3px 10px;
}

.calc-topic-head {
  display: flex; align-items: baseline; gap: 14px;
  margin: 56px 0 24px;
}
.calc-topic-head h2 {
  font-size: 26px; margin: 0; padding-bottom: 8px;
  border-bottom: 2px solid var(--gold); display: inline-block;
}
.calc-topic-head .count { font-size: 13px; color: var(--mist-text); }

/* ===== CITABLE DEFINITION (AI overviews / featured snippet) ===== */
.calc-definition {
  background: var(--paper);
  border-left: 4px solid var(--gold);
  padding: 18px 22px;
  margin: 0 0 32px;
  font-size: 17px;
  line-height: 1.6;
  color: var(--ink);
}
.calc-definition strong { color: var(--wine); }
.calc-definition .mono { font-family: 'JetBrains Mono', monospace; color: var(--gold-text); }

/* ===== FAQ BLOCK ===== */
.calc-faq { margin: 56px 0 0; }
.calc-faq h2 {
  font-size: 26px;
  margin: 0 0 18px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--gold);
  display: inline-block;
}
.calc-faq details {
  border-bottom: 1px solid var(--rule);
  padding: 4px 0;
}
.calc-faq summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 44px 18px 0;
  font-family: 'Spectral', Georgia, serif;
  font-size: 19px;
  font-weight: 500;
  color: var(--ink);
  position: relative;
}
.calc-faq summary::-webkit-details-marker { display: none; }
.calc-faq summary::after {
  content: '+';
  position: absolute;
  right: 6px; top: 50%;
  transform: translateY(-50%);
  font-family: 'Spectral', serif;
  font-size: 26px; color: var(--gold); font-weight: 300;
}
.calc-faq details[open] summary::after { content: '−'; }
.calc-faq details p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-3);
}

@media (max-width: 600px) {
  .pfc { padding: 20px; }
  .pfc-result-value { font-size: 30px; }
  .calc-formula { font-size: 18px; }
  .calc-faq summary { font-size: 17px; }
}