/* ==========================================================================
   I HATE CALCULATOR DESIGN SYSTEM — WARM EDITORIAL & SWISS UTILITY
   Independent, Grounded, Human-Crafted Aesthetic (US / EU / AU Standards)
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;600;700&family=Newsreader:ital,opsz,wght@0,6..72,400;0,6..72,500;0,6..72,600;0,6..72,700;1,6..72,400;1,6..72,600&display=swap');

:root {
  /* Typography Families — Institutional Financial Standard */
  --font-serif: 'Newsreader', Georgia, Cambria, 'Times New Roman', Times, serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  --font-financial: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* Color Palette - Warm Editorial Light Mode (Paper & Ink) */
  --bg-app: #faf9f6;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f5f4ef;
  --bg-surface-alt: #f0eee8;
  --bg-card-hover: #ffffff;
  --border-subtle: #e5e3dc;
  --border-focus: #0f2942;
  --border-hover: #cfcbc1;

  --text-primary: #191816;
  --text-secondary: #4a4741;
  --text-muted: #79756d;
  --text-inverse: #ffffff;

  /* High-Trust Editorial Accents (No neon, pure grounded tones) */
  --brand-primary: #0f2942;        /* Oxford Navy - authoritative & grounded */
  --brand-primary-hover: #173d61;
  --brand-primary-light: #1e3a8a;
  --brand-primary-subtle: #eef3f8;
  
  --btn-primary-bg: #0f2942;
  --btn-primary-fg: #ffffff;
  --btn-primary-hover: #173d61;

  --brand-sand-light: #f5f4ef;
  
  --brand-accent: #b45309;         /* Warm amber / honey */
  --brand-accent-subtle: #fef3c7;

  --brand-forest: #166534;         /* British racing green / savings green */
  --brand-forest-subtle: #dcfce7;

  --brand-brick: #991b1b;          /* Traditional bookbinding red for costs */
  --brand-brick-subtle: #fee2e2;

  --brand-slate: #334155;
  --brand-slate-subtle: #f1f5f9;

  /* Subtle Warm Lighting */
  --grad-subtle: linear-gradient(180deg, #ffffff 0%, #faf9f6 100%);

  /* Tangible Shadows & Paper Depth */
  --shadow-xs: 0 1px 2px rgba(25, 24, 22, 0.04);
  --shadow-sm: 0 1px 3px rgba(25, 24, 22, 0.06), 0 1px 2px rgba(25, 24, 22, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(25, 24, 22, 0.06), 0 2px 4px -2px rgba(25, 24, 22, 0.03);
  --shadow-lg: 0 10px 15px -3px rgba(25, 24, 22, 0.06), 0 4px 6px -4px rgba(25, 24, 22, 0.02);
  --shadow-card: 0 1px 3px rgba(25, 24, 22, 0.05), 0 0 0 1px rgba(25, 24, 22, 0.06);

  /* Spacing & Radii */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.25rem;
  --radius-full: 9999px;

  /* Layout Standards - Sleek 56px modern header */
  --header-height: 3.5rem;
  --max-w-content: 1220px;
}

/* Warm Charcoal Slate Dark Mode (Editorial evening study mode) */
[data-theme="dark"] {
  --bg-app: #131312;
  --bg-surface: #1c1c19;
  --bg-surface-elevated: #252521;
  --bg-surface-alt: #1e1e1b;
  --bg-card-hover: #262622;
  --border-subtle: #303029;
  --border-focus: #60a5fa;
  --border-hover: #4a4a40;

  --text-primary: #f5f4ef;
  --text-secondary: #c5c2b8;
  --text-muted: #848177;
  --text-inverse: #131312;

  --brand-primary: #60a5fa;        /* Crisp, legible blue accent */
  --brand-primary-hover: #93c5fd;
  --brand-primary-light: #93c5fd;
  --brand-primary-subtle: rgba(96, 165, 250, 0.14);

  --btn-primary-bg: #f5f4ef;       /* Solid, high-contrast primary buttons in dark mode */
  --btn-primary-fg: #131312;
  --btn-primary-hover: #e5e3dc;

  --brand-sand-light: #252521;

  --brand-accent: #fbbf24;
  --brand-accent-subtle: rgba(251, 191, 36, 0.16);

  --brand-forest: #4ade80;
  --brand-forest-subtle: rgba(74, 222, 128, 0.14);

  --brand-brick: #f87171;
  --brand-brick-subtle: rgba(248, 113, 113, 0.15);

  --brand-slate: #cbd5e1;
  --brand-slate-subtle: rgba(203, 213, 225, 0.1);

  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.6);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.08);
}

/* CSS Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  color: var(--text-primary);
  background-color: var(--bg-app);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-app);
  color: var(--text-primary);
  transition: background-color 0.2s ease, color 0.2s ease;
  overflow-x: hidden;
}

/* Financial Engineering Typography & Tabular Lining Figures */
.tabular-nums, .financial-nums,
input[type="number"], .calc-input-box input,
.stat-val, .calc-result-value,
.amort-table td, .matrix-table td, .term-monthly,
.term-interest, .badge-mono, .calc-input-prefix, .calc-input-suffix {
  font-family: var(--font-financial);
  font-variant-numeric: tabular-nums lining-nums;
  font-feature-settings: "tnum" 1, "lnum" 1, "zero" 1;
  letter-spacing: -0.015em;
}

a {
  color: inherit;
  text-decoration: none;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  background: none;
  border: none;
}

/* Universal Input & Select Theme Consistency */
select, .calc-select {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-hover);
  border-radius: var(--radius-md);
  padding: 0.5rem 0.75rem;
  font-size: 0.88rem;
  outline: none;
  transition: border-color 0.15s ease;
}

select option, .calc-select option {
  background-color: var(--bg-surface);
  color: var(--text-primary);
}

select:focus, .calc-select:focus {
  border-color: var(--border-focus);
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-w-content);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

@media (max-width: 640px) {
  .container {
    padding-left: 1rem;
    padding-right: 1rem;
  }
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.7rem;
  padding: 0.2rem 0.55rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border: 1px solid transparent;
}

.badge-brand {
  background-color: var(--brand-primary-subtle);
  color: var(--brand-primary);
  border-color: var(--brand-primary-subtle);
}

.badge-editorial {
  background-color: var(--bg-surface-elevated);
  color: var(--text-secondary);
  border-color: var(--border-subtle);
}

.badge-amber, .badge-hot {
  background-color: var(--brand-accent-subtle);
  color: var(--brand-accent);
  border-color: var(--brand-accent-subtle);
}

.badge-forest, .badge-new {
  background-color: var(--brand-forest-subtle);
  color: var(--brand-forest);
  border-color: var(--brand-forest-subtle);
}

.badge-pill {
  border-radius: var(--radius-full);
}

/* Buttons - Tactile & Grounded */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  font-weight: 600;
  font-size: 0.85rem;
  padding: 0.45rem 1rem;
  border-radius: var(--radius-md);
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--btn-primary-bg);
  color: var(--btn-primary-fg);
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(0, 0, 0, 0.1);
}

.btn-primary:hover {
  background-color: var(--btn-primary-hover);
  color: var(--btn-primary-fg);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-xs);
}

.btn-outline:hover {
  background-color: var(--bg-surface-elevated);
  border-color: var(--border-hover);
  color: var(--text-primary);
}

.btn-sm {
  font-size: 0.78rem;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sm);
}

.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
  flex-shrink: 0;
}

.btn-icon:hover {
  border-color: var(--border-hover);
  color: var(--text-primary);
  background: var(--bg-surface);
  transform: scale(1.05);
}