/* =========================================================
   DESIGN TOKENS & RESET
   ========================================================= */
:root {
  --bg-base:        #0B1220;
  --bg-surface:     #111A2E;
  --bg-card:        #151F35;
  --border-card:    rgba(255, 255, 255, 0.08);
  --border-subtle:  rgba(255, 255, 255, 0.05);

  --text-primary:   #E6EDF7;
  --text-muted:     #94A3B8;
  --text-faint:     #4B5675;

  --accent:         #10B981;
  --accent-dim:     rgba(16, 185, 129, 0.15);
  --accent-glow:    rgba(16, 185, 129, 0.3);
  --cyan:           #22D3EE;
  --cyan-dim:       rgba(34, 211, 238, 0.15);
  --amber:          #F59E0B;
  --amber-dim:      rgba(245, 158, 11, 0.15);
  --danger:         #EF4444;
  --danger-dim:     rgba(239, 68, 68, 0.15);

  --radius-sm:      8px;
  --radius-md:      12px;
  --radius-lg:      16px;
  --radius-xl:      24px;

  --font-sans:      'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --shadow-card:    0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-elevated:0 8px 40px rgba(0, 0, 0, 0.5);

  --max-width:      1100px;
  --nav-height:     60px;

  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  background-color: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* =========================================================
   TYPOGRAPHY
   ========================================================= */
h1 { font-size: clamp(2rem, 5vw, 3.25rem); font-weight: 800; line-height: 1.15; letter-spacing: -0.02em; }
h2 { font-size: clamp(1.5rem, 3.5vw, 2.25rem); font-weight: 700; line-height: 1.25; letter-spacing: -0.015em; }
h3 { font-size: clamp(1.125rem, 2.5vw, 1.5rem); font-weight: 600; line-height: 1.3; }
h4 { font-size: 1.125rem; font-weight: 600; }

p { color: var(--text-primary); max-width: 68ch; }
p + p { margin-top: 1rem; }

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-base), opacity var(--transition-base);
}
a:hover,
a:focus-visible { color: #34d399; text-decoration: underline; }

strong { color: var(--text-primary); font-weight: 600; }
em { font-style: italic; color: var(--text-muted); }

ul, ol { padding-left: 1.5rem; }
li { margin-bottom: 0.4rem; color: var(--text-primary); }
li + li { margin-top: 0.25rem; }

/* =========================================================
   FOCUS STYLES
   ========================================================= */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* =========================================================
   READING PROGRESS BAR
   ========================================================= */
#reading-progress {
  position: fixed;
  top: var(--nav-height);
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--cyan));
  z-index: 1001;
  transition: width 0.1s linear;
  box-shadow: 0 0 8px var(--accent-glow);
}

/* =========================================================
   NAVIGATION
   ========================================================= */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--nav-height);
  background: rgba(11, 18, 32, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-card);
  display: flex;
  align-items: center;
}

.nav-inner {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.nav-brand {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
}
.nav-brand:hover { color: var(--accent); text-decoration: none; }
.nav-brand-dot { color: var(--accent); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
  padding: 0;
  flex-wrap: wrap;
}

.nav-links a {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-base), background-color var(--transition-base);
  white-space: nowrap;
}
.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--text-primary);
  background: var(--border-card);
  text-decoration: none;
}

@media (max-width: 640px) {
  .nav-links { display: none; }
}

/* =========================================================
   LAYOUT CONTAINERS
   ========================================================= */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

section {
  padding: 5rem 0;
}

section + section {
  border-top: 1px solid var(--border-subtle);
}

.section-label {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
  display: block;
}

.section-header {
  margin-bottom: 3rem;
}

.section-header h2 { margin-bottom: 0.75rem; }
.section-header p { color: var(--text-muted); font-size: 1.0625rem; }

/* =========================================================
   CARDS
   ========================================================= */
.card {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-card);
}

.card-sm {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}

/* =========================================================
   HERO SECTION
   ========================================================= */
#hero {
  padding: 6rem 0 5rem;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(16, 185, 129, 0.06) 0%, transparent 70%);
  border-bottom: 1px solid var(--border-subtle);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent-dim);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.375rem 0.875rem;
  border-radius: 100px;
  margin-bottom: 1.75rem;
}

#hero h1 {
  margin-bottom: 1.25rem;
  background: linear-gradient(135deg, var(--text-primary) 60%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-summary {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin-bottom: 3rem;
  max-width: 60ch;
}

.stat-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-chip {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 1rem 1.5rem;
  min-width: 160px;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.stat-chip-value {
  font-size: 1.875rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.stat-chip-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
  line-height: 1.4;
}

.hero-disclaimer {
  font-size: 0.75rem;
  color: var(--text-faint);
  font-style: italic;
  margin-top: 0.75rem;
}

/* =========================================================
   BUSINESS PROBLEM — SLIDER WIDGET
   ========================================================= */
.churn-calculator {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-top: 2.5rem;
}

.churn-calculator h3 {
  margin-bottom: 0.5rem;
}

.calculator-disclaimer {
  font-size: 0.8rem;
  color: var(--text-faint);
  font-style: italic;
  margin-bottom: 1.5rem;
}

.slider-row {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 2rem;
}

.slider-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.slider-label {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-primary);
}

.slider-value-display {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  min-width: 4ch;
  text-align: right;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  background: var(--border-card);
  border-radius: 100px;
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
  cursor: pointer;
  transition: box-shadow var(--transition-base);
}

input[type="range"]::-webkit-slider-thumb:hover {
  box-shadow: 0 0 0 6px var(--accent-dim);
}

input[type="range"]::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
  cursor: pointer;
}

.calculator-results {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}

.calc-result-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  text-align: center;
}

.calc-result-number {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--danger);
  font-variant-numeric: tabular-nums;
  display: block;
}

.calc-result-number.positive { color: var(--accent); }

.calc-result-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
  display: block;
}

/* =========================================================
   METHODOLOGY — TABS
   ========================================================= */
.tab-nav {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 0;
  border-bottom: 1px solid var(--border-card);
  flex-wrap: wrap;
}

.tab-btn {
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  padding: 0.75rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  transition: color var(--transition-base), border-color var(--transition-base);
  margin-bottom: -1px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  font-family: var(--font-sans);
}

.tab-btn:hover { color: var(--text-primary); }

.tab-btn[aria-selected="true"] {
  color: var(--accent);
  border-bottom-color: var(--accent);
  background: var(--accent-dim);
}

.tab-panel {
  display: none;
  padding: 1.75rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-top: none;
  border-radius: 0 0 var(--radius-lg) var(--radius-lg);
}

.tab-panel[aria-hidden="false"] { display: block; }

.metrics-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.metric-chip {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.6rem 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.2rem;
  min-width: 90px;
}

.metric-chip-value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.metric-chip-name {
  font-size: 0.6875rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* =========================================================
   CHARTS
   ========================================================= */
.chart-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.chart-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-card);
}

.chart-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.chart-wrapper {
  position: relative;
  width: 100%;
}

.chart-wrapper canvas {
  max-width: 100%;
}

/* =========================================================
   CONFUSION MATRIX
   ========================================================= */
.confusion-matrix-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}

.confusion-axis-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-align: center;
}

.confusion-grid-wrapper {
  position: relative;
}

.confusion-y-label {
  position: absolute;
  left: -3rem;
  top: 50%;
  transform: translateY(-50%) rotate(-90deg);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  white-space: nowrap;
}

.confusion-grid {
  display: grid;
  grid-template-columns: auto 1fr 1fr;
  grid-template-rows: auto 1fr 1fr;
  gap: 6px;
  width: 320px;
}

.confusion-header-cell {
  background: none;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  padding: 0.5rem;
}

.confusion-row-header {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: 0 0.75rem 0 0;
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  white-space: nowrap;
}

.confusion-cell {
  border-radius: var(--radius-md);
  padding: 1.25rem 1rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  cursor: pointer;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  position: relative;
}

.confusion-cell:hover,
.confusion-cell:focus-visible {
  transform: scale(1.04);
  box-shadow: 0 6px 20px rgba(0,0,0,0.4);
  z-index: 1;
  outline: 2px solid var(--accent);
}

.confusion-cell.tp { background: rgba(16, 185, 129, 0.2); border: 1px solid rgba(16, 185, 129, 0.4); }
.confusion-cell.tn { background: rgba(34, 211, 238, 0.15); border: 1px solid rgba(34, 211, 238, 0.35); }
.confusion-cell.fp { background: rgba(245, 158, 11, 0.15); border: 1px solid rgba(245, 158, 11, 0.35); }
.confusion-cell.fn { background: rgba(239, 68, 68, 0.2); border: 1px solid rgba(239, 68, 68, 0.4); }

.confusion-cell-abbr {
  font-size: 1.375rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}
.tp .confusion-cell-abbr { color: var(--accent); }
.tn .confusion-cell-abbr { color: var(--cyan); }
.fp .confusion-cell-abbr { color: var(--amber); }
.fn .confusion-cell-abbr { color: var(--danger); }

.confusion-cell-label {
  font-size: 0.6875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.confusion-cell-count {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-faint);
  font-variant-numeric: tabular-nums;
}

/* Tooltip */
.cm-tooltip {
  position: absolute;
  bottom: calc(100% + 12px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-md);
  padding: 0.875rem 1rem;
  font-size: 0.8125rem;
  color: var(--text-primary);
  width: 220px;
  box-shadow: var(--shadow-elevated);
  z-index: 10;
  pointer-events: none;
  opacity: 0;
  transition: opacity var(--transition-base);
  text-align: left;
}

.cm-tooltip.visible { opacity: 1; }

.cm-tooltip::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--border-card);
}

/* =========================================================
   DETAILS / DATA TABLES
   ========================================================= */
details {
  margin-top: 1rem;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

summary {
  padding: 0.625rem 1rem;
  cursor: pointer;
  font-size: 0.8125rem;
  color: var(--text-muted);
  background: var(--bg-card);
  user-select: none;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: color var(--transition-base), background-color var(--transition-base);
}

summary::-webkit-details-marker { display: none; }
summary::before {
  content: '▶';
  font-size: 0.625rem;
  transition: transform var(--transition-base);
  flex-shrink: 0;
}
details[open] summary::before { transform: rotate(90deg); }
summary:hover { color: var(--text-primary); background: var(--border-subtle); }

.data-table-wrapper {
  overflow-x: auto;
  padding: 0.75rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
}

thead th {
  background: var(--bg-card);
  color: var(--text-muted);
  font-weight: 600;
  text-align: left;
  padding: 0.625rem 0.875rem;
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

tbody td {
  padding: 0.625rem 0.875rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-primary);
  vertical-align: middle;
}

tbody tr:last-child td { border-bottom: none; }
tbody tr:hover td { background: var(--border-subtle); }

/* =========================================================
   SIMULATOR
   ========================================================= */
#simulador {
  background: linear-gradient(180deg, var(--bg-base) 0%, rgba(16, 185, 129, 0.03) 100%);
}

.simulator-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 768px) {
  .simulator-layout { grid-template-columns: 1fr; }
}

.simulator-controls {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
}

.sim-field {
  margin-bottom: 1.25rem;
}

.sim-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.4rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
}

.sim-label-value {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.sim-select {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  padding: 0.625rem 0.875rem;
  cursor: pointer;
  transition: border-color var(--transition-base);
  -webkit-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%2394A3B8' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.875rem center;
  padding-right: 2.5rem;
}

.sim-select:focus { outline: 2px solid var(--accent); outline-offset: 2px; border-color: var(--accent); }

.btn-reset {
  background: none;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.5rem 1rem;
  cursor: pointer;
  margin-top: 0.5rem;
  transition: color var(--transition-base), border-color var(--transition-base), background-color var(--transition-base);
}

.btn-reset:hover {
  color: var(--text-primary);
  border-color: var(--text-muted);
  background: var(--border-subtle);
}

/* Gauge */
.simulator-result {
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}

.gauge-container {
  position: relative;
  width: 220px;
  height: 120px;
  overflow: visible;
}

.gauge-svg {
  width: 220px;
  height: 120px;
  overflow: visible;
}

.gauge-track {
  fill: none;
  stroke: var(--border-card);
  stroke-width: 18;
  stroke-linecap: round;
}

.gauge-fill {
  fill: none;
  stroke-width: 18;
  stroke-linecap: round;
  transition: stroke-dashoffset 0.6s cubic-bezier(0.34, 1.56, 0.64, 1), stroke 0.4s ease;
  transform-origin: center;
  transform: rotate(-180deg) scaleX(-1);
}

.gauge-center-text {
  text-anchor: middle;
  dominant-baseline: middle;
}

.gauge-percent {
  font-size: 2rem;
  font-weight: 800;
  fill: var(--text-primary);
  font-family: var(--font-sans);
}

.gauge-sublabel {
  font-size: 0.75rem;
  fill: var(--text-muted);
  font-family: var(--font-sans);
}

.risk-tier-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1.25rem;
  border-radius: 100px;
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  border: 1px solid;
}

.risk-tier-badge.bajo   { background: var(--accent-dim); border-color: rgba(16,185,129,0.4); color: var(--accent); }
.risk-tier-badge.medio  { background: var(--amber-dim);  border-color: rgba(245,158,11,0.4);  color: var(--amber);  }
.risk-tier-badge.alto   { background: var(--danger-dim); border-color: rgba(239,68,68,0.4);   color: var(--danger); }

.risk-action-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  width: 100%;
}

.risk-action-label {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-faint);
  margin-bottom: 0.4rem;
  display: block;
}

.risk-action-text {
  font-size: 0.875rem;
  color: var(--text-primary);
  line-height: 1.5;
}

.sim-disclaimer {
  font-size: 0.75rem;
  color: var(--text-faint);
  font-style: italic;
  text-align: center;
  padding: 0.75rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  margin-top: 0.5rem;
}

/* =========================================================
   IMPACT / ROI TABLE
   ========================================================= */
.impact-table-wrapper {
  overflow-x: auto;
  margin-top: 1.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-card);
  background: var(--bg-surface);
}

.impact-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.impact-table thead th {
  padding: 0.875rem 1.25rem;
  background: var(--bg-card);
  font-size: 0.75rem;
  text-align: left;
}

.impact-table tbody td {
  padding: 0.875rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
}

.impact-table tbody tr:last-child td { border-bottom: none; }

.impact-highlight {
  color: var(--accent);
  font-weight: 700;
}

/* =========================================================
   ARCHITECTURE DIAGRAM
   ========================================================= */
.arch-wrapper {
  position: relative;
  background: var(--bg-surface);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: 2rem;
  overflow: hidden;
  margin-top: 1.5rem;
}

.arch-diagram {
  display: block;
  max-width: 100%;
  margin: 0 auto;
  overflow: visible;
}

/* SVG node styles */
.arch-node {
  cursor: pointer;
  transition: transform 0.2s ease;
}

.arch-node:hover .node-bg,
.arch-node:focus .node-bg {
  filter: brightness(1.3);
}

.arch-node:focus { outline: none; }
.arch-node:focus .node-bg { stroke: var(--accent); stroke-width: 2; }

.arch-node:active { transform: scale(0.97); }

.node-bg {
  transition: filter var(--transition-base);
}

.node-label {
  font-family: var(--font-sans);
  font-size: 11px;
  font-weight: 600;
  fill: var(--text-primary);
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
}

.node-sublabel {
  font-family: var(--font-sans);
  font-size: 9px;
  fill: var(--text-muted);
  text-anchor: middle;
  dominant-baseline: middle;
  pointer-events: none;
}

.arch-arrow {
  fill: none;
  stroke: var(--border-card);
  stroke-width: 1.5;
  marker-end: url(#arrowhead);
}

.arch-label {
  font-family: var(--font-sans);
  font-size: 9px;
  fill: var(--text-faint);
  text-anchor: middle;
}

/* Side panel */
.arch-panel {
  position: absolute;
  top: 0;
  right: 0;
  width: 280px;
  height: 100%;
  background: var(--bg-card);
  border-left: 1px solid var(--border-card);
  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
  padding: 1.5rem;
  transform: translateX(100%);
  transition: transform var(--transition-slow);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.arch-panel.open { transform: translateX(0); }

.arch-panel-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: 1px solid var(--border-card);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-size: 1.125rem;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  line-height: 1;
  font-family: var(--font-sans);
  transition: color var(--transition-base);
}
.arch-panel-close:hover { color: var(--text-primary); }

.arch-panel h4 {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-primary);
  padding-right: 2rem;
}

.arch-panel-tech {
  display: inline-flex;
  align-items: center;
  background: var(--accent-dim);
  border: 1px solid rgba(16,185,129,0.25);
  color: var(--accent);
  font-size: 0.6875rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: 100px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.arch-panel p { font-size: 0.8125rem; color: var(--text-muted); max-width: none; }

@media (max-width: 640px) {
  .arch-panel {
    position: fixed;
    top: var(--nav-height);
    right: 0;
    height: calc(100dvh - var(--nav-height));
    border-radius: 0;
    width: 90%;
    max-width: 320px;
    z-index: 999;
  }
}

.arch-caption {
  font-size: 0.75rem;
  color: var(--text-faint);
  text-align: center;
  margin-top: 1rem;
  font-style: italic;
}

/* =========================================================
   AUTHOR / CTA
   ========================================================= */
.author-card {
  background: linear-gradient(135deg, var(--bg-surface) 0%, rgba(16, 185, 129, 0.05) 100%);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: 3rem 2.5rem;
  display: flex;
  align-items: center;
  gap: 2.5rem;
  flex-wrap: wrap;
}

.author-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent) 0%, var(--cyan) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 800;
  color: var(--bg-base);
  flex-shrink: 0;
}

.author-info { flex: 1; min-width: 200px; }
.author-info h3 { margin-bottom: 0.25rem; }
.author-info p { color: var(--text-muted); font-size: 0.9375rem; max-width: none; }

.author-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.75rem;
}

.author-tag {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 100px;
  padding: 0.25rem 0.75rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent);
  color: var(--bg-base);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 700;
  padding: 0.875rem 2rem;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: background-color var(--transition-base), transform var(--transition-base), box-shadow var(--transition-base);
  white-space: nowrap;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: #0ea572;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--accent-glow);
  text-decoration: none;
  color: var(--bg-base);
}

/* =========================================================
   FOOTER
   ========================================================= */
.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-card);
  padding: 3rem 0 2rem;
  margin-top: 0;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 640px) {
  .footer-inner { grid-template-columns: 1fr; }
}

.footer-brand {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.footer-brand:hover { color: var(--accent); text-decoration: none; }
.footer-brand span { color: var(--accent); }

.footer-byline {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 0.35rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  align-items: flex-end;
}

@media (max-width: 640px) {
  .footer-links { align-items: flex-start; }
}

.footer-links-label {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-faint);
  margin-bottom: 0.25rem;
}

.footer-links a {
  font-size: 0.8125rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-base);
}

.footer-links a:hover { color: var(--accent); }

.footer-divider {
  border: none;
  border-top: 1px solid var(--border-subtle);
  margin: 1.5rem 0 1rem;
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  font-size: 0.75rem;
  color: var(--text-faint);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* =========================================================
   SCROLL REVEAL
   ========================================================= */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* =========================================================
   UTILITY
   ========================================================= */
.text-accent  { color: var(--accent); }
.text-cyan    { color: var(--cyan); }
.text-amber   { color: var(--amber); }
.text-danger  { color: var(--danger); }
.text-muted   { color: var(--text-muted); }

.mt-1  { margin-top: 0.5rem; }
.mt-2  { margin-top: 1rem; }
.mt-3  { margin-top: 1.5rem; }
.mt-4  { margin-top: 2rem; }
.mb-1  { margin-bottom: 0.5rem; }
.mb-2  { margin-bottom: 1rem; }
.mb-3  { margin-bottom: 1.5rem; }

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}

/* =========================================================
   PROBLEM SECTION — INFO BOX
   ========================================================= */
.insight-box {
  background: var(--accent-dim);
  border: 1px solid rgba(16,185,129,0.25);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1rem 1.25rem;
  margin-top: 1.25rem;
  font-size: 0.9375rem;
  color: var(--text-primary);
}

.warning-box {
  background: var(--amber-dim);
  border: 1px solid rgba(245,158,11,0.25);
  border-left: 3px solid var(--amber);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1rem 1.25rem;
  margin-top: 1rem;
  font-size: 0.875rem;
  color: var(--text-primary);
}

/* =========================================================
   FEATURE IMPORTANCE — INLINE BAR
   ========================================================= */
.fi-bar-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding-top: 0.5rem;
}

.fi-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.8125rem;
}

.fi-label {
  flex: 0 0 140px;
  color: var(--text-muted);
  text-align: right;
  white-space: nowrap;
}

.fi-bar-bg {
  flex: 1;
  background: var(--border-card);
  border-radius: 100px;
  height: 8px;
  overflow: hidden;
}

.fi-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--cyan));
  border-radius: 100px;
  width: 0%;
  transition: width 0.8s cubic-bezier(0.22, 1, 0.36, 1);
}

.fi-value {
  flex: 0 0 42px;
  color: var(--text-primary);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  text-align: right;
}