/* ── CSS Custom Properties ─────────────────────────────────────────────────── */
:root {
  --brand-amber:    #F59E0B;
  --brand-amberdk:  #D97706;
  --brand-slate:    #0F172A;
  --brand-slatemid: #1E293B;
  --brand-slatelit: #334155;
  --brand-offwhite: #F8FAFC;
  --transition-base: 200ms ease;
}

/* ── Base Resets ────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background-color: var(--brand-slate);
  color: var(--brand-offwhite);
}

/* ── Tab System ─────────────────────────────────────────────────────────────── */
.tab-btn {
  position: relative;
  padding: 0.625rem 1.5rem;
  border-radius: 0.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: #94a3b8;
  transition: color var(--transition-base), background-color var(--transition-base);
  cursor: pointer;
  border: none;
  background: transparent;
  white-space: nowrap;
}

.tab-btn:hover { color: #fff; }

.tab-btn.tab-active {
  background-color: var(--brand-amber);
  color: var(--brand-slate);
}

/* ── Input Fields ────────────────────────────────────────────────────────────── */
.calc-input {
  width: 100%;
  background-color: var(--brand-slatemid);
  border: 1.5px solid var(--brand-slatelit);
  border-radius: 0.625rem;
  padding: 0.75rem 1rem;
  color: var(--brand-offwhite);
  font-size: 1rem;
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
  outline: none;
}

.calc-input:focus {
  border-color: var(--brand-amber);
  box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.18);
}

.calc-input::placeholder { color: #475569; }

/* Remove number input spinners */
.calc-input[type=number]::-webkit-inner-spin-button,
.calc-input[type=number]::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }
.calc-input[type=number] { -moz-appearance: textfield; }

/* Select */
select.calc-input {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2394a3b8' stroke-width='2'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' d='M19 9l-7 7-7-7'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  background-size: 1rem;
  padding-right: 2.5rem;
  cursor: pointer;
}

/* ── Buttons ────────────────────────────────────────────────────────────────── */
.btn-primary {
  background-color: var(--brand-amber);
  color: var(--brand-slate);
  font-weight: 700;
  padding: 0.75rem 2rem;
  border-radius: 0.625rem;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  transition: background-color var(--transition-base), transform var(--transition-base), box-shadow var(--transition-base);
  box-shadow: 0 4px 14px rgba(245, 158, 11, 0.35);
}

.btn-primary:hover {
  background-color: var(--brand-amberdk);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(245, 158, 11, 0.45);
}

.btn-primary:active { transform: translateY(0); }

.btn-secondary {
  background-color: transparent;
  color: #94a3b8;
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  border-radius: 0.625rem;
  border: 1.5px solid var(--brand-slatelit);
  cursor: pointer;
  font-size: 0.9rem;
  transition: color var(--transition-base), border-color var(--transition-base);
}

.btn-secondary:hover { color: #fff; border-color: #64748b; }

/* ── Result Cards ────────────────────────────────────────────────────────────── */
.result-card {
  background: linear-gradient(135deg, var(--brand-slatemid) 0%, #1a2744 100%);
  border: 1px solid var(--brand-slatelit);
  border-radius: 1rem;
  padding: 1.25rem 1rem;
  text-align: center;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.result-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.4);
}

.result-card .result-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--brand-amber);
  line-height: 1.2;
  font-variant-numeric: tabular-nums;
}

.result-card .result-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: #94a3b8;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: 0.25rem;
}

/* ── Animations ──────────────────────────────────────────────────────────────── */
@keyframes fade-in {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.animate-fade-in { animation: fade-in 0.35s ease-out both; }

@keyframes pulse-amber {
  0%, 100% { box-shadow: 0 0 0 0 rgba(245, 158, 11, 0); }
  50%       { box-shadow: 0 0 0 6px rgba(245, 158, 11, 0.15); }
}

.pulse-amber { animation: pulse-amber 2s ease-in-out infinite; }

/* ── Hero Section ────────────────────────────────────────────────────────────── */
.hero-gradient {
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #1a2744 100%);
}

/* ── Card / Panel ────────────────────────────────────────────────────────────── */
.panel {
  background-color: var(--brand-slatemid);
  border: 1px solid var(--brand-slatelit);
  border-radius: 1rem;
}

/* ── Table ───────────────────────────────────────────────────────────────────── */
.history-table th {
  background-color: #0f172a;
  color: #64748b;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.75rem 1rem;
}

/* ── Prose (SEO content pages) ───────────────────────────────────────────────── */
.prose-dark h1, .prose-dark h2, .prose-dark h3 { color: var(--brand-offwhite); }
.prose-dark h2 { font-size: 1.5rem; font-weight: 700; margin: 2rem 0 0.75rem; }
.prose-dark h3 { font-size: 1.125rem; font-weight: 600; margin: 1.5rem 0 0.5rem; color: var(--brand-amber); }
.prose-dark p  { color: #cbd5e1; line-height: 1.75; margin-bottom: 1rem; }
.prose-dark ul { list-style: disc; padding-left: 1.5rem; color: #cbd5e1; margin-bottom: 1rem; }
.prose-dark li { margin-bottom: 0.5rem; line-height: 1.7; }
.prose-dark a  { color: var(--brand-amber); text-decoration: underline; }
.prose-dark a:hover { color: var(--brand-amberdk); }

/* ── FAQ Accordion ────────────────────────────────────────────────────────────── */
.faq-item summary {
  cursor: pointer;
  padding: 1rem;
  font-weight: 600;
  color: var(--brand-offwhite);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: '+'; color: var(--brand-amber); font-size: 1.25rem; font-weight: 300; }
.faq-item[open] summary::after { content: '−'; }

.faq-item .faq-body {
  padding: 0 1rem 1rem;
  color: #94a3b8;
  line-height: 1.7;
  font-size: 0.9rem;
}

/* ── Print Styles ────────────────────────────────────────────────────────────── */
@media print {
  header, footer, nav, #history-section { display: none !important; }
  body { background: white; color: black; }
  .result-card { border: 1px solid #ccc; page-break-inside: avoid; }
  .result-card .result-value { color: #0f172a; }
}

/* ── Scrollbar ────────────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--brand-slate); }
::-webkit-scrollbar-thumb { background: var(--brand-slatelit); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #475569; }