/* ==========================================================================
   SellerRTO Design System & Stylesheet
   Option B: Simple Utility Website
   Clean, Fast, Mobile-First, Accessible
   ========================================================================== */

:root {
  /* Brand & Palette */
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #eff6ff;
  --color-primary-border: #bfdbfe;

  --color-success: #16a34a;
  --color-success-dark: #15803d;
  --color-success-bg: #ecfdf5;
  --color-success-border: #bbf7d0;

  --color-danger: #dc2626;
  --color-danger-dark: #b91c1c;
  --color-danger-bg: #fef2f2;
  --color-danger-border: #fecaca;

  --color-warning: #d97706;
  --color-warning-bg: #fffbeb;
  --color-warning-border: #fde68a;

  /* Neutrals & Text */
  --color-text-main: #0f172a;       /* Dark navy text */
  --color-text-muted: #334155;      /* Secondary text */
  --color-text-subtle: #64748b;     /* Tertiary/caption text */
  --color-bg-page: #f8fafc;         /* Page background */
  --color-bg-surface: #ffffff;      /* Card/white background */
  --color-bg-subtle: #f1f5f9;       /* Input & neutral highlight */
  --color-bg-input: #ffffff;
  --color-border: #e2e8f0;
  --color-border-hover: #cbd5e1;
  --color-border-focus: #2563eb;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-md: 1.125rem;   /* 18px */
  --font-size-lg: 1.25rem;    /* 20px */
  --font-size-xl: 1.5rem;     /* 24px */
  --font-size-2xl: 1.875rem;  /* 30px */
  --font-size-3xl: 2.25rem;   /* 36px */

  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;

  /* Spacing */
  --space-2xs: 0.25rem; /* 4px */
  --space-xs: 0.5rem;   /* 8px */
  --space-sm: 0.75rem;  /* 12px */
  --space-md: 1rem;     /* 16px */
  --space-lg: 1.5rem;   /* 24px */
  --space-xl: 2rem;     /* 32px */
  --space-2xl: 3rem;    /* 48px */
  --space-3xl: 4rem;    /* 64px */

  /* Radii & Elevation */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-full: 9999px;

  --shadow-sm: 0 1px 2px 0 rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.08), 0 2px 4px -2px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.03);

  /* Container */
  --container-max-width: 1100px;
}

/* ==========================================================================
   CSS Reset & Base Rules
   ========================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-main);
  background-color: var(--color-bg-page);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

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

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

/* Accessible focus styling */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ==========================================================================
   Layout & Containers
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-md);
  padding-right: var(--space-md);
}

.main-content {
  flex: 1 0 auto;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-header {
  background-color: var(--color-bg-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  text-decoration: none;
  color: var(--color-text-main);
}

.brand-link:hover {
  text-decoration: none;
}

.brand-logo-icon {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.brand-text-wrap {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.brand-name span {
  color: var(--color-primary);
}

.brand-tagline-sub {
  font-size: var(--font-size-xs);
  color: var(--color-text-subtle);
  font-weight: var(--font-weight-medium);
}

/* Navigation Links */
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  list-style: none;
}

.nav-link {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
  padding: var(--space-xs) var(--space-xs);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: all 0.15s ease;
}

.nav-link:hover {
  color: var(--color-primary);
  text-decoration: none;
  background-color: var(--color-primary-light);
}

.nav-link.active {
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

/* Mobile Nav Toggle */
.menu-toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background-color: var(--color-bg-surface);
  color: var(--color-text-main);
}

.menu-toggle:hover {
  background-color: var(--color-bg-subtle);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  background-color: var(--color-bg-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-xl) 0 var(--space-lg) 0;
  text-align: center;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-sm);
  border: 1px solid var(--color-primary-border);
}

.hero-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  line-height: var(--line-height-tight);
  margin-bottom: var(--space-xs);
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: var(--font-size-md);
  color: var(--color-text-muted);
  max-width: 680px;
  margin: 0 auto;
  line-height: var(--line-height-relaxed);
}

/* ==========================================================================
   Buttons & Form Controls
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: 10px 18px;
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  text-decoration: none;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #ffffff;
  border: 1px solid var(--color-primary);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  color: #ffffff;
}

.btn-secondary {
  background-color: var(--color-bg-surface);
  color: var(--color-text-main);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background-color: var(--color-bg-subtle);
  border-color: var(--color-border-hover);
}

.btn-outline-primary {
  background-color: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary-border);
}

.btn-outline-primary:hover {
  background-color: var(--color-primary-light);
  color: var(--color-primary-hover);
}

.btn-icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* Input Styles */
.form-group {
  margin-bottom: var(--space-md);
}

.form-label-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}

.form-label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  gap: 6px;
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.input-prefix, .input-suffix {
  position: absolute;
  color: var(--color-text-subtle);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  pointer-events: none;
}

.input-prefix {
  left: 12px;
}

.input-suffix {
  right: 12px;
}

.form-input {
  width: 100%;
  height: 44px;
  padding: 8px 12px;
  background-color: var(--color-bg-input);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  color: var(--color-text-main);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.has-prefix .form-input {
  padding-left: 28px;
}

.has-suffix .form-input {
  padding-right: 32px;
}

.form-input:hover {
  border-color: var(--color-border-hover);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.form-input.is-invalid {
  border-color: var(--color-danger);
  background-color: #fffafb;
}

.form-input.is-invalid:focus {
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.15);
}

.input-error-msg {
  display: none;
  font-size: var(--font-size-xs);
  color: var(--color-danger);
  margin-top: 4px;
  font-weight: var(--font-weight-medium);
}

.form-input.is-invalid ~ .input-error-msg,
.form-group.has-error .input-error-msg {
  display: block;
}

.form-help-text {
  font-size: var(--font-size-xs);
  color: var(--color-text-subtle);
  margin-top: 4px;
}

/* Tooltip */
.tooltip-trigger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  border-radius: var(--radius-full);
  background-color: var(--color-bg-subtle);
  color: var(--color-text-subtle);
  font-size: 11px;
  font-weight: var(--font-weight-bold);
  cursor: help;
  position: relative;
  border: 1px solid var(--color-border);
}

.tooltip-trigger:hover, .tooltip-trigger:focus {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  border-color: var(--color-primary-border);
}

.tooltip-trigger .tooltip-content {
  visibility: hidden;
  opacity: 0;
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--color-text-main);
  color: #ffffff;
  padding: 8px 12px;
  border-radius: var(--radius-md);
  font-size: var(--font-size-xs);
  line-height: 1.4;
  width: 240px;
  text-align: left;
  z-index: 50;
  box-shadow: var(--shadow-lg);
  pointer-events: none;
  transition: opacity 0.15s ease, visibility 0.15s ease;
  font-weight: var(--font-weight-regular);
}

.tooltip-trigger .tooltip-content::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  margin-left: -5px;
  border-width: 5px;
  border-style: solid;
  border-color: var(--color-text-main) transparent transparent transparent;
}

.tooltip-trigger:hover .tooltip-content,
.tooltip-trigger:focus .tooltip-content {
  visibility: visible;
  opacity: 1;
}

/* ==========================================================================
   Calculator Grid & Cards
   ========================================================================== */

.calculator-section {
  padding: var(--space-xl) 0;
}

.calculator-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: var(--space-xl);
  align-items: start;
}

.calc-card {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
}

.calc-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}

.calc-card-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.calc-card-title-icon {
  width: 20px;
  height: 20px;
  color: var(--color-primary);
}

/* Fieldset styling inside forms */
.input-section-title {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-subtle);
  margin-top: var(--space-md);
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: 8px;
}

.input-section-title::after {
  content: "";
  flex: 1;
  height: 1px;
  background-color: var(--color-border);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.calc-actions {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  margin-top: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
}

/* ==========================================================================
   Results Dashboard
   ========================================================================== */

.results-wrapper {
  position: sticky;
  top: 88px;
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

/* Primary Metric Cards */
.metrics-primary-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.metric-card {
  padding: var(--space-md);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background-color: var(--color-bg-surface);
  position: relative;
}

.metric-card.loss-highlight {
  background-color: #fff9f9;
  border-color: #fed7d7;
}

.metric-card.cost-highlight {
  background-color: #f8fafc;
  border-color: var(--color-border);
}

.metric-label {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-subtle);
  margin-bottom: 4px;
}

.metric-value {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  line-height: 1.15;
}

.metric-card.loss-highlight .metric-value {
  color: var(--color-danger);
}

.metric-sub {
  font-size: var(--font-size-xs);
  color: var(--color-text-subtle);
  margin-top: 4px;
}

/* Detailed Cost Breakdown Table/List */
.breakdown-section {
  margin-top: var(--space-md);
}

.breakdown-title {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  margin-bottom: var(--space-sm);
}

.breakdown-list {
  list-style: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.breakdown-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 14px;
  font-size: var(--font-size-sm);
  background-color: var(--color-bg-surface);
  border-bottom: 1px solid var(--color-border);
}

.breakdown-item:last-child {
  border-bottom: none;
}

.breakdown-item:nth-child(even) {
  background-color: var(--color-bg-subtle);
}

.breakdown-label {
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.breakdown-val {
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-main);
  font-variant-numeric: tabular-nums;
}

/* Quick Order Summary Bar */
.order-split-bar-wrap {
  margin-bottom: var(--space-md);
  padding: 12px;
  background-color: var(--color-bg-subtle);
  border-radius: var(--radius-md);
}

.order-split-header {
  display: flex;
  justify-content: space-between;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
  margin-bottom: 6px;
}

.order-split-progress {
  display: flex;
  height: 8px;
  border-radius: var(--radius-full);
  overflow: hidden;
  background-color: #e2e8f0;
}

.order-split-progress-cod {
  background-color: #f97316; /* warm amber for COD */
}

.order-split-progress-prepaid {
  background-color: var(--color-primary); /* blue for prepaid */
}

/* ==========================================================================
   Target Savings Comparison Section
   ========================================================================== */

.target-savings-card {
  background: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-top: var(--space-xl);
  box-shadow: var(--shadow-sm);
}

.target-savings-header {
  margin-bottom: var(--space-md);
}

.target-savings-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.target-savings-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-top: 4px;
}

.savings-result-banner {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-success-border);
  background-color: var(--color-success-bg);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.savings-result-banner.no-savings {
  border-color: var(--color-border);
  background-color: var(--color-bg-subtle);
  grid-template-columns: 1fr;
  text-align: center;
}

.savings-metric-title {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  color: var(--color-success-dark);
  letter-spacing: 0.04em;
}

.savings-metric-val {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-success);
  line-height: 1.15;
}

.no-savings-title {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-muted);
}

.no-savings-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-subtle);
  margin-top: 4px;
}

/* ==========================================================================
   Assumptions & Disclaimers Box
   ========================================================================== */

.assumptions-box {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-top: var(--space-xl);
}

.assumptions-title {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  margin-bottom: var(--space-sm);
}

.assumptions-quote {
  padding: 12px 16px;
  background-color: #f8fafc;
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-main);
  font-style: italic;
  margin-bottom: var(--space-md);
}

.assumptions-list {
  padding-left: var(--space-lg);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
}

.assumptions-list li {
  margin-bottom: 6px;
}

/* ==========================================================================
   Content Sections (How It Works, FAQs, Guides)
   ========================================================================== */

.info-section {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--color-border);
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto var(--space-xl) auto;
}

.section-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  margin-bottom: var(--space-xs);
}

.section-subtitle {
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
}

/* Step Cards */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
}

.step-card {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  position: relative;
}

.step-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-xs);
  margin-bottom: var(--space-sm);
}

.step-title {
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  margin-bottom: var(--space-xs);
}

.step-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
}

/* FAQ Accordion / Details */
.faq-grid {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.faq-item {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-main);
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--color-bg-surface);
  transition: background-color 0.15s ease;
}

.faq-question:hover {
  background-color: var(--color-bg-subtle);
}

.faq-icon {
  width: 18px;
  height: 18px;
  color: var(--color-text-subtle);
  transition: transform 0.2s ease;
  flex-shrink: 0;
}

.faq-item.is-open .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  display: none;
  padding: 0 var(--space-lg) var(--space-md) var(--space-lg);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
}

.faq-item.is-open .faq-answer {
  display: block;
}

/* Feature/Guide Cards */
.guides-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-lg);
}

.guide-card {
  background-color: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}

.guide-card:hover {
  border-color: var(--color-primary-border);
  box-shadow: var(--shadow-md);
  text-decoration: none;
}

.guide-tag {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-xs);
}

.guide-title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  margin-bottom: var(--space-xs);
}

.guide-desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-md);
}

.guide-link-text {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* Article / Long-form Page Typography */
.article-header {
  padding: var(--space-xl) 0 var(--space-lg) 0;
  background-color: var(--color-bg-surface);
  border-bottom: 1px solid var(--color-border);
}

.article-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  line-height: var(--line-height-tight);
  margin-bottom: var(--space-xs);
}

.article-lead {
  font-size: var(--font-size-md);
  color: var(--color-text-muted);
  max-width: 800px;
  line-height: var(--line-height-relaxed);
}

.article-content {
  padding: var(--space-2xl) 0;
  max-width: 820px;
}

.article-content h2 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
}

.article-content h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-main);
  margin-top: var(--space-lg);
  margin-bottom: var(--space-xs);
}

.article-content p {
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-md);
}

.article-content ul, .article-content ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-xl);
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
}

.article-content li {
  margin-bottom: 8px;
}

.article-callout {
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-primary);
  background-color: var(--color-bg-surface);
  box-shadow: var(--shadow-sm);
  margin: var(--space-lg) 0;
}

.article-callout.warning {
  border-left-color: var(--color-warning);
  background-color: var(--color-warning-bg);
}

.formula-card {
  background-color: #0f172a;
  color: #f8fafc;
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: var(--font-size-sm);
  line-height: 1.6;
  margin: var(--space-lg) 0;
  overflow-x: auto;
}

.formula-card .comment {
  color: #94a3b8;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  background-color: #0f172a;
  color: #94a3b8;
  border-top: 1px solid #1e293b;
  padding: var(--space-2xl) 0 var(--space-xl) 0;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, 1fr);
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand-name {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: #ffffff;
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: var(--space-xs);
}

.footer-brand-name span {
  color: #60a5fa;
}

.footer-desc {
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
  color: #94a3b8;
  margin-bottom: var(--space-md);
  max-width: 320px;
}

.footer-heading {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  color: #ffffff;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-md);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-link {
  font-size: var(--font-size-sm);
  color: #94a3b8;
  text-decoration: none;
  transition: color 0.15s ease;
}

.footer-link:hover {
  color: #ffffff;
  text-decoration: none;
}

.footer-bottom {
  padding-top: var(--space-lg);
  border-top: 1px solid #1e293b;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: var(--font-size-xs);
  color: #64748b;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

/* ==========================================================================
   Print Stylesheet (@media print)
   ========================================================================== */

@media print {
  body {
    background-color: #ffffff !important;
    color: #000000 !important;
    font-size: 12pt;
  }

  .site-header,
  .site-footer,
  .calc-actions,
  .hero-pill,
  .menu-toggle,
  .tooltip-trigger,
  .info-section,
  .target-savings-header p {
    display: none !important;
  }

  .container {
    max-width: 100% !important;
    padding: 0 !important;
  }

  .calculator-grid {
    display: block !important;
  }

  .calc-card,
  .target-savings-card,
  .assumptions-box {
    box-shadow: none !important;
    border: 1px solid #cccccc !important;
    page-break-inside: avoid;
    margin-bottom: 20pt !important;
  }

  .results-wrapper {
    position: static !important;
  }

  .print-header {
    display: block !important;
    border-bottom: 2px solid #000000;
    padding-bottom: 10pt;
    margin-bottom: 15pt;
  }

  .print-header .print-report-title {
    font-size: 18pt;
    font-weight: bold;
    margin-bottom: 4pt;
  }

  .print-header p {
    font-size: 10pt;
    color: #555555;
  }
}

.print-header {
  display: none;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

/* Tablet (max 992px) */
@media (max-width: 992px) {
  .calculator-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .results-wrapper {
    position: static;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
  }

  .steps-grid {
    grid-template-columns: 1fr;
  }
}

/* Mobile (max 768px) */
@media (max-width: 768px) {
  .hero-title {
    font-size: var(--font-size-2xl);
  }

  .hero-subtitle {
    font-size: var(--font-size-base);
  }

  .menu-toggle {
    display: inline-flex;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background-color: var(--color-bg-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md);
    box-shadow: var(--shadow-md);
  }

  .site-nav.is-open {
    display: block;
  }

  .nav-links {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }

  .nav-link {
    padding: 10px 14px;
    font-size: var(--font-size-base);
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .metrics-primary-grid {
    grid-template-columns: 1fr;
  }

  .savings-result-banner {
    grid-template-columns: 1fr;
  }

  .guides-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* Small mobile (max 390px / 360px) */
@media (max-width: 390px) {
  .container {
    padding-left: var(--space-sm);
    padding-right: var(--space-sm);
  }

  .calc-card,
  .target-savings-card,
  .assumptions-box {
    padding: var(--space-md);
  }

  .calc-actions {
    flex-direction: column;
  }

  .calc-actions .btn {
    width: 100%;
  }

  .metric-value {
    font-size: var(--font-size-lg);
  }

  .savings-metric-val {
    font-size: var(--font-size-xl);
  }
}