/* ============================================================
   NeonFit Premium BMI Calculator — styles.css
   Cyberpunk / Glassmorphism theme with neon variants
   ============================================================ */

/* ---- Google Fonts ---- */
@import url('https://fonts.googleapis.com/css2?family=Orbitron:wght@400;600;700;900&family=Inter:wght@300;400;500;600;700&display=swap');

/* ============================================================
   CSS CUSTOM PROPERTIES — Theme Tokens
   ============================================================ */
:root {
  /* Base colors */
  --bg-primary: #050a05;
  --bg-secondary: #0a0f0a;
  --bg-card: rgba(10, 20, 10, 0.7);
  --bg-card-hover: rgba(15, 30, 15, 0.85);
  --bg-input: rgba(5, 15, 5, 0.8);

  /* Neon Green (default) */
  --neon: #00ff88;
  --neon-dim: #00cc6a;
  --neon-dark: #009944;
  --neon-glow: rgba(0, 255, 136, 0.35);
  --neon-glow-soft: rgba(0, 255, 136, 0.12);
  --neon-glow-ultra: rgba(0, 255, 136, 0.6);

  /* Text */
  --text-primary: #e8ffe8;
  --text-secondary: #8aaa8a;
  --text-muted: #4a6a4a;

  /* Borders */
  --border: rgba(0, 255, 136, 0.18);
  --border-hover: rgba(0, 255, 136, 0.45);

  /* BMI category colors */
  --cat-underweight: #00bfff;
  --cat-normal: #00ff88;
  --cat-overweight: #ffa500;
  --cat-obese1: #ff4500;
  --cat-obese2: #ff0040;

  /* Transitions */
  --transition-fast: 0.18s ease;
  --transition-mid: 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
  --transition-slow: 0.6s cubic-bezier(0.25, 0.8, 0.25, 1);

  /* Border radius */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;

  /* Fonts */
  --font-display: 'Orbitron', 'Courier New', monospace;
  --font-body: 'Inter', system-ui, sans-serif;

  /* Shadows */
  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.5), 0 0 0 1px var(--border);
  --shadow-neon: 0 0 20px var(--neon-glow), 0 0 60px var(--neon-glow-soft);
  --shadow-neon-strong: 0 0 30px var(--neon-glow-ultra), 0 0 80px var(--neon-glow);
}

/* ---- Blue Theme ---- */
.theme-blue {
  --bg-primary: #020510;
  --bg-secondary: #050a18;
  --bg-card: rgba(5, 10, 25, 0.75);
  --bg-card-hover: rgba(8, 16, 38, 0.88);
  --bg-input: rgba(3, 6, 18, 0.85);
  --neon: #00d4ff;
  --neon-dim: #00a8cc;
  --neon-dark: #007a99;
  --neon-glow: rgba(0, 212, 255, 0.35);
  --neon-glow-soft: rgba(0, 212, 255, 0.12);
  --neon-glow-ultra: rgba(0, 212, 255, 0.6);
  --text-primary: #e0f8ff;
  --text-secondary: #6aacbc;
  --text-muted: #2a5a6a;
  --border: rgba(0, 212, 255, 0.18);
  --border-hover: rgba(0, 212, 255, 0.45);
  --cat-normal: #00d4ff;
}

/* ---- Purple Theme ---- */
.theme-purple {
  --bg-primary: #06020f;
  --bg-secondary: #0e0518;
  --bg-card: rgba(14, 5, 28, 0.75);
  --bg-card-hover: rgba(22, 8, 44, 0.88);
  --bg-input: rgba(8, 3, 18, 0.85);
  --neon: #bf00ff;
  --neon-dim: #9900cc;
  --neon-dark: #6600aa;
  --neon-glow: rgba(191, 0, 255, 0.35);
  --neon-glow-soft: rgba(191, 0, 255, 0.12);
  --neon-glow-ultra: rgba(191, 0, 255, 0.6);
  --text-primary: #f0e0ff;
  --text-secondary: #9a7abc;
  --text-muted: #4a2a6a;
  --border: rgba(191, 0, 255, 0.18);
  --border-hover: rgba(191, 0, 255, 0.45);
  --cat-normal: #bf00ff;
}

/* ============================================================
   RESET & BASE
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color 0.5s ease, color 0.3s ease;
  position: relative;
}

/* ============================================================
   ANIMATED BACKGROUND
   ============================================================ */
.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px),
    linear-gradient(90deg, var(--border) 1px, transparent 1px);
  background-size: 48px 48px;
  opacity: 0.4;
  pointer-events: none;
  z-index: 0;
  animation: gridPulse 8s ease-in-out infinite;
}

@keyframes gridPulse {
  0%, 100% { opacity: 0.35; }
  50% { opacity: 0.55; }
}

#particleCanvas {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.5;
}

/* ============================================================
   HEADER
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(5, 10, 5, 0.82);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 0 30px var(--neon-glow-soft), 0 2px 24px rgba(0,0,0,0.5);
  transition: background 0.3s ease, border-color 0.3s ease;
}

.header-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 64px;
  display: flex;
  align-items: center;
  gap: 2rem;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  flex-shrink: 0;
}

.logo-icon {
  font-size: 1.8rem;
  color: var(--neon);
  text-shadow: 0 0 12px var(--neon), 0 0 24px var(--neon-glow);
  animation: logoPulse 3s ease-in-out infinite;
  line-height: 1;
}

@keyframes logoPulse {
  0%, 100% { text-shadow: 0 0 12px var(--neon), 0 0 24px var(--neon-glow); }
  50% { text-shadow: 0 0 20px var(--neon), 0 0 50px var(--neon-glow), 0 0 80px var(--neon-glow-soft); }
}

.logo-text {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.05em;
}

.logo-accent {
  color: var(--neon);
  text-shadow: 0 0 10px var(--neon-glow);
}

/* Header Nav */
.header-nav {
  display: flex;
  gap: 0.25rem;
  margin-left: auto;
}

.nav-btn {
  padding: 0.45rem 1.1rem;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  position: relative;
  letter-spacing: 0.02em;
}

.nav-btn:hover {
  color: var(--neon);
  background: var(--neon-glow-soft);
}

.nav-btn.active {
  color: var(--neon);
  background: var(--neon-glow-soft);
}

.nav-btn.active::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 50%;
  transform: translateX(-50%);
  width: 60%;
  height: 2px;
  background: var(--neon);
  box-shadow: 0 0 8px var(--neon);
  border-radius: 2px;
}

/* Header Controls */
.header-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.theme-switcher {
  display: flex;
  gap: 0.4rem;
  align-items: center;
}

.theme-dot {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  padding: 0;
}

.theme-dot.theme-green { background: #00ff88; }
.theme-dot.theme-blue { background: #00d4ff; }
.theme-dot.theme-purple { background: #bf00ff; }

.theme-dot.active, .theme-dot:hover {
  border-color: white;
  transform: scale(1.25);
  box-shadow: 0 0 10px currentColor;
}

.icon-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.icon-btn:hover {
  color: var(--neon);
  border-color: var(--neon);
  box-shadow: 0 0 12px var(--neon-glow);
}

/* ============================================================
   MAIN LAYOUT
   ============================================================ */
#main-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem;
  position: relative;
  z-index: 1;
}

/* ============================================================
   TAB PANELS
   ============================================================ */
.tab-panel { display: none; }
.tab-panel.active { display: block; }
.hidden { display: none !important; }

/* ============================================================
   GLASS CARD
   ============================================================ */
.glass-card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  transition: border-color var(--transition-mid), box-shadow var(--transition-mid), background var(--transition-mid);
}

.glass-card:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-card), 0 0 30px var(--neon-glow-soft);
}

/* ============================================================
   CALCULATOR LAYOUT
   ============================================================ */
.calculator-layout {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 1.5rem;
  align-items: start;
}

@media (max-width: 900px) {
  .calculator-layout {
    grid-template-columns: 1fr;
  }
}

/* ============================================================
   INPUT PANEL
   ============================================================ */
.input-panel {
  padding: 2rem 1.75rem;
  position: sticky;
  top: 80px;
}

.panel-title {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  margin-bottom: 0.4rem;
  line-height: 1.2;
}

.neon-text {
  color: var(--neon);
  text-shadow: 0 0 10px var(--neon-glow), 0 0 20px var(--neon-glow-soft);
}

.panel-subtitle {
  font-size: 0.83rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

/* Unit Toggle */
.unit-toggle-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.toggle-label {
  font-size: 0.83rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.toggle-track {
  display: flex;
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
  gap: 2px;
}

.toggle-option {
  padding: 0.3rem 0.9rem;
  border-radius: 999px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.toggle-option.active {
  background: var(--neon);
  color: #000;
  font-weight: 700;
  box-shadow: 0 0 12px var(--neon-glow);
}

/* Field Sections */
.field-section {
  margin-bottom: 1.25rem;
}

.section-heading {
  font-family: var(--font-display);
  font-size: 0.72rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--neon);
  margin-bottom: 0.9rem;
  opacity: 0.9;
}

/* Collapsible */
.collapsible-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--neon);
  padding: 0.5rem 0;
  border-top: 1px solid var(--border);
  margin-top: 0.5rem;
  font-family: var(--font-display);
  font-size: 0.72rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  transition: color var(--transition-fast);
}

.collapsible-trigger:hover { color: var(--text-primary); }

.chevron {
  transition: transform var(--transition-mid);
  display: inline-block;
}

.collapsible-trigger[aria-expanded="true"] .chevron {
  transform: rotate(180deg);
}

.collapsible-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.collapsible-body.open {
  max-height: 900px;
}

/* Field Groups */
.field-group {
  margin-bottom: 1rem;
  position: relative;
}

.field-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.optional-tag {
  font-size: 0.68rem;
  color: var(--text-muted);
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
}

/* Input Row */
.input-row {
  display: flex;
  gap: 0.6rem;
}

.input-wrapper {
  flex: 1;
  position: relative;
}

.neon-input {
  width: 100%;
  padding: 0.65rem 2.8rem 0.65rem 0.9rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  outline: none;
  appearance: textfield;
  -moz-appearance: textfield;
}

.neon-input::-webkit-inner-spin-button,
.neon-input::-webkit-outer-spin-button { -webkit-appearance: none; }

.neon-input::placeholder { color: var(--text-muted); }

.neon-input:focus {
  border-color: var(--neon);
  box-shadow: 0 0 0 2px var(--neon-glow-soft), 0 0 16px var(--neon-glow-soft);
  background: rgba(0, 255, 136, 0.04);
}

.input-unit {
  position: absolute;
  right: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--neon);
  pointer-events: none;
  letter-spacing: 0.05em;
}

/* Tooltip */
.tooltip-trigger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  border: 1px solid var(--text-muted);
  font-size: 0.65rem;
  color: var(--text-muted);
  cursor: help;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.tooltip-trigger:hover, .tooltip-trigger:focus {
  border-color: var(--neon);
  color: var(--neon);
  box-shadow: 0 0 8px var(--neon-glow);
  outline: none;
}

.tooltip-box {
  display: none;
  position: absolute;
  bottom: calc(100% + 6px);
  left: 0;
  background: rgba(0, 0, 0, 0.92);
  border: 1px solid var(--border-hover);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem;
  font-size: 0.78rem;
  color: var(--text-primary);
  z-index: 50;
  max-width: 260px;
  line-height: 1.5;
  box-shadow: 0 4px 20px rgba(0,0,0,0.7), 0 0 12px var(--neon-glow-soft);
  pointer-events: none;
}

.tooltip-trigger:hover + .input-row ~ .tooltip-box,
.tooltip-trigger:focus + .input-row ~ .tooltip-box,
.field-label:hover .tooltip-trigger ~ .tooltip-box { display: block; }

/* Gender Toggle */
.gender-toggle {
  display: flex;
  gap: 0.5rem;
}

.gender-btn {
  flex: 1;
  padding: 0.55rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-input);
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
}

.gender-btn:hover {
  border-color: var(--neon);
  color: var(--neon);
}

.gender-btn.active {
  background: var(--neon-glow-soft);
  border-color: var(--neon);
  color: var(--neon);
  box-shadow: 0 0 12px var(--neon-glow);
}

/* Select */
.select-wrapper {
  position: relative;
}

.neon-select {
  width: 100%;
  padding: 0.65rem 2.2rem 0.65rem 0.9rem;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.85rem;
  outline: none;
  appearance: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.neon-select:focus {
  border-color: var(--neon);
  box-shadow: 0 0 0 2px var(--neon-glow-soft);
}

.neon-select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.select-arrow {
  position: absolute;
  right: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--neon);
  pointer-events: none;
  font-size: 0.8rem;
}

/* Buttons */
.calc-btn {
  width: 100%;
  padding: 0.9rem 1.5rem;
  background: var(--neon);
  border: none;
  border-radius: var(--radius-md);
  color: #000;
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: all var(--transition-fast);
  text-transform: uppercase;
  margin-top: 1.25rem;
  box-shadow: 0 0 20px var(--neon-glow), 0 4px 16px rgba(0,0,0,0.4);
}

.calc-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  transform: translateX(-100%);
  transition: transform 0.55s ease;
}

.calc-btn:hover::before { transform: translateX(100%); }

.calc-btn:hover {
  box-shadow: 0 0 35px var(--neon-glow), 0 0 70px var(--neon-glow-soft), 0 6px 24px rgba(0,0,0,0.5);
  transform: translateY(-2px);
}

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

.btn-text { position: relative; z-index: 1; }

.reset-btn {
  width: 100%;
  padding: 0.6rem 1rem;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-top: 0.5rem;
  font-family: var(--font-body);
}

.reset-btn:hover {
  border-color: #ff4444;
  color: #ff4444;
}

/* ============================================================
   RESULTS PANEL
   ============================================================ */
.results-panel {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Empty State */
.empty-state {
  padding: 3rem 2rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.empty-icon {
  color: var(--neon);
  animation: spinSlow 12s linear infinite;
  opacity: 0.7;
}

@keyframes spinSlow {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.empty-title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  letter-spacing: 0.06em;
  color: var(--neon);
}

.empty-subtitle {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  max-width: 340px;
}

.feature-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: center;
  margin-top: 0.5rem;
}

.pill {
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--border-hover);
  border-radius: 999px;
  font-size: 0.75rem;
  color: var(--neon);
  background: var(--neon-glow-soft);
  font-weight: 600;
  letter-spacing: 0.05em;
}

/* Result Card */
.result-card {
  padding: 1.5rem 1.75rem;
  animation: fadeSlideUp 0.45s cubic-bezier(0.25, 0.8, 0.25, 1) both;
}

@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.card-title {
  font-family: var(--font-display);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--neon);
  margin-bottom: 1.25rem;
  opacity: 0.9;
}

/* ============================================================
   GAUGE
   ============================================================ */
.gauge-card {
  text-align: center;
}

.gauge-wrapper {
  position: relative;
  display: inline-block;
  width: 220px;
  margin: 0 auto 0.75rem;
}

.gauge-svg {
  width: 220px;
  height: 130px;
  overflow: visible;
}

.gauge-label {
  font-family: var(--font-display);
  font-size: 9px;
  fill: var(--text-muted);
  font-weight: 600;
}

.gauge-center {
  position: absolute;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
}

.bmi-value {
  font-family: var(--font-display);
  font-size: 2.4rem;
  font-weight: 900;
  color: var(--neon);
  text-shadow: 0 0 20px var(--neon-glow), 0 0 40px var(--neon-glow-soft);
  line-height: 1;
  letter-spacing: -0.02em;
  transition: all 0.5s ease;
}

.bmi-unit {
  font-family: var(--font-display);
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.15em;
  margin-top: 2px;
}

.bmi-category-badge {
  display: inline-block;
  padding: 0.4rem 1.5rem;
  border-radius: 999px;
  border: 1px solid var(--neon);
  color: var(--neon);
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  background: var(--neon-glow-soft);
  box-shadow: 0 0 12px var(--neon-glow-soft);
  margin-bottom: 1.25rem;
  transition: all 0.4s ease;
}

/* BMI Scale Bar */
.bmi-scale {
  margin-top: 0.5rem;
}

.scale-bar {
  display: flex;
  height: 10px;
  border-radius: 999px;
  overflow: hidden;
  gap: 2px;
}

.scale-seg {
  border-radius: 2px;
  position: relative;
  display: flex;
  align-items: flex-end;
}

.scale-seg.underweight { background: #00bfff; }
.scale-seg.normal { background: #00ff88; }
.scale-seg.overweight { background: #ffa500; }
.scale-seg.obese1 { background: #ff4500; }
.scale-seg.obese2 { background: #ff0040; }

.scale-label {
  position: absolute;
  top: 14px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.55rem;
  white-space: nowrap;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

.scale-ticks {
  display: flex;
  justify-content: space-between;
  margin-top: 20px;
  font-size: 0.65rem;
  color: var(--text-muted);
  font-family: var(--font-display);
  letter-spacing: 0.05em;
}

.scale-pointer-track {
  position: relative;
  height: 10px;
  margin-top: 4px;
}

.scale-pointer {
  position: absolute;
  top: 0;
  width: 12px;
  height: 10px;
  background: var(--neon);
  border-radius: 2px;
  transform: translateX(-50%);
  box-shadow: 0 0 8px var(--neon);
  transition: left 0.7s cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* ============================================================
   METRICS GRID
   ============================================================ */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}

.metric-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.2rem 1.25rem;
  transition: all var(--transition-mid);
  cursor: default;
  position: relative;
  overflow: hidden;
}

.metric-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--neon-glow-soft) 0%, transparent 60%);
  opacity: 0;
  transition: opacity var(--transition-mid);
}

.metric-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.5), 0 0 20px var(--neon-glow-soft);
}

.metric-card:hover::before { opacity: 1; }

.metric-icon {
  font-size: 1.3rem;
  margin-bottom: 0.5rem;
  line-height: 1;
}

.metric-value {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--neon);
  text-shadow: 0 0 10px var(--neon-glow-soft);
  line-height: 1.2;
  margin-bottom: 0.2rem;
}

.metric-label {
  font-size: 0.72rem;
  color: var(--text-secondary);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 0.15rem;
}

.metric-sub {
  font-size: 0.68rem;
  color: var(--text-muted);
  line-height: 1.4;
}

/* ============================================================
   PROGRESS RINGS
   ============================================================ */
.progress-ring-card {}

.rings-row {
  display: flex;
  justify-content: space-around;
  gap: 1rem;
  flex-wrap: wrap;
}

.ring-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
  flex: 1;
  min-width: 80px;
}

.ring-svg {
  width: 80px;
  height: 80px;
}

.ring-bg {
  fill: none;
  stroke: rgba(255,255,255,0.06);
  stroke-width: 8;
}

.ring-progress {
  fill: none;
  stroke: var(--neon);
  stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 188.5;
  stroke-dashoffset: 188.5;
  transform: rotate(-90deg);
  transform-origin: center;
  transition: stroke-dashoffset 1.2s cubic-bezier(0.25, 0.8, 0.25, 1);
  filter: drop-shadow(0 0 4px var(--neon));
}

.ring-label-wrap { text-align: center; }

.ring-value {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--neon);
  line-height: 1;
}

.ring-label {
  font-size: 0.68rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-top: 0.2rem;
}

/* ============================================================
   CALORIE BREAKDOWN
   ============================================================ */
.calorie-bars {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.calorie-row {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

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

.calorie-label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.calorie-val {
  font-family: var(--font-display);
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--neon);
}

.calorie-bar-track {
  height: 6px;
  background: rgba(255,255,255,0.06);
  border-radius: 999px;
  overflow: hidden;
}

.calorie-bar-fill {
  height: 100%;
  border-radius: 999px;
  background: var(--neon);
  box-shadow: 0 0 8px var(--neon-glow);
  width: 0;
  transition: width 1s cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* ============================================================
   RECOMMENDATIONS
   ============================================================ */
.reco-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.reco-item {
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  padding: 0.85rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: rgba(0,0,0,0.2);
  transition: all var(--transition-fast);
  animation: fadeSlideUp 0.4s ease both;
}

.reco-item:hover {
  border-color: var(--border-hover);
  background: var(--neon-glow-soft);
}

.reco-icon { font-size: 1.2rem; flex-shrink: 0; line-height: 1.4; }

.reco-text {
  font-size: 0.84rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

.reco-text strong {
  color: var(--text-primary);
  font-weight: 600;
  display: block;
  margin-bottom: 0.15rem;
}

/* ============================================================
   ACTION BUTTONS
   ============================================================ */
.actions-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.action-btn {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-body);
  letter-spacing: 0.02em;
}

.action-btn:hover {
  border-color: var(--neon);
  color: var(--neon);
  box-shadow: 0 0 12px var(--neon-glow);
  background: var(--neon-glow-soft);
}

.action-btn.danger:hover {
  border-color: #ff4444;
  color: #ff4444;
  box-shadow: 0 0 12px rgba(255, 68, 68, 0.3);
  background: rgba(255, 68, 68, 0.08);
}

/* ============================================================
   HISTORY TAB
   ============================================================ */
.history-layout {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.section-title {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.history-actions {
  display: flex;
  gap: 0.5rem;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.history-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  flex-wrap: wrap;
  cursor: pointer;
}

.history-item:hover {
  border-color: var(--border-hover);
  background: var(--bg-card-hover);
  box-shadow: 0 0 16px var(--neon-glow-soft);
}

.history-date {
  font-size: 0.75rem;
  color: var(--text-muted);
  flex-shrink: 0;
  font-family: var(--font-display);
  letter-spacing: 0.04em;
}

.history-bmi {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--neon);
  flex-shrink: 0;
  min-width: 60px;
}

.history-cat {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: var(--neon-glow-soft);
  border: 1px solid var(--border);
  color: var(--neon);
  flex-shrink: 0;
}

.history-meta {
  font-size: 0.78rem;
  color: var(--text-secondary);
  flex: 1;
  min-width: 120px;
}

.history-delete {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.9rem;
  padding: 0.25rem;
  border-radius: 4px;
  transition: color var(--transition-fast);
  flex-shrink: 0;
}

.history-delete:hover { color: #ff4444; }

.history-empty {
  text-align: center;
  padding: 3rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.history-chart-card {
  padding: 1.5rem;
}

#historyChart {
  max-height: 220px;
}

/* ============================================================
   FAQ TAB
   ============================================================ */
.faq-layout {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

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

.faq-item:hover { border-color: var(--border-hover); }

.faq-question {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.25rem;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-primary);
  font-size: 0.9rem;
  font-weight: 600;
  text-align: left;
  gap: 1rem;
  transition: color var(--transition-fast);
  font-family: var(--font-body);
}

.faq-question:hover { color: var(--neon); }

.faq-chevron {
  flex-shrink: 0;
  font-size: 0.8rem;
  color: var(--neon);
  transition: transform var(--transition-mid);
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease;
}

.faq-item.open .faq-answer {
  max-height: 300px;
}

.faq-answer-inner {
  padding: 0 1.25rem 1rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
  border-top: 1px solid var(--border);
  padding-top: 0.75rem;
}

/* ============================================================
   TOAST
   ============================================================ */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: rgba(10, 20, 10, 0.95);
  border: 1px solid var(--neon);
  border-radius: var(--radius-sm);
  padding: 0.8rem 1.25rem;
  font-size: 0.85rem;
  color: var(--text-primary);
  box-shadow: 0 0 20px var(--neon-glow), 0 8px 32px rgba(0,0,0,0.6);
  z-index: 999;
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: all 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
  max-width: 320px;
  backdrop-filter: blur(10px);
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

/* ============================================================
   MODAL
   ============================================================ */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.75);
  backdrop-filter: blur(6px);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-box {
  position: relative;
  padding: 2rem;
  max-width: 440px;
  width: 100%;
  animation: fadeSlideUp 0.35s ease both;
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 1.1rem;
  padding: 0.25rem;
  transition: color var(--transition-fast);
}

.modal-close:hover { color: var(--text-primary); }

.modal-title {
  font-family: var(--font-display);
  font-size: 1rem;
  letter-spacing: 0.08em;
  color: var(--neon);
  margin-bottom: 1.25rem;
}

.share-url-wrap {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.share-url-wrap .neon-input { font-size: 0.8rem; }

.share-socials {
  display: flex;
  gap: 0.5rem;
}

.social-btn {
  flex: 1;
  padding: 0.6rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-body);
}

.social-btn:hover {
  border-color: var(--neon);
  color: var(--neon);
}

/* ============================================================
   PRINT STYLES
   ============================================================ */
@media print {
  .site-header, .input-panel, .empty-state,
  .actions-card, #particleCanvas, .bg-grid,
  .header-controls, .header-nav { display: none !important; }

  body {
    background: white;
    color: black;
  }

  .glass-card {
    border: 1px solid #ccc;
    box-shadow: none;
    background: white;
  }

  .neon-text, .bmi-value, .metric-value,
  .card-title, .bmi-category-badge {
    color: #000;
    text-shadow: none;
  }

  .calculator-layout {
    grid-template-columns: 1fr;
  }

  .results-panel { width: 100%; }
}

/* ============================================================
   SCROLLBAR
   ============================================================ */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 999px; }
::-webkit-scrollbar-thumb:hover { background: var(--neon-dim); }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
  #main-content { padding: 1rem; }

  .header-inner { padding: 0 1rem; gap: 0.75rem; }

  .logo-text { font-size: 1.1rem; }

  .input-panel { padding: 1.5rem 1.25rem; position: relative; top: 0; }

  .metrics-grid { grid-template-columns: repeat(2, 1fr); }

  .rings-row { gap: 0.5rem; }

  .gauge-wrapper { width: 180px; }
  .gauge-svg { width: 180px; height: 108px; }
  .bmi-value { font-size: 1.9rem; }
}

@media (max-width: 480px) {
  .header-nav .nav-btn { padding: 0.35rem 0.65rem; font-size: 0.8rem; }
  .theme-switcher { display: none; }
  .metrics-grid { grid-template-columns: 1fr 1fr; }
  .actions-row { gap: 0.4rem; }
  .action-btn { padding: 0.45rem 0.7rem; font-size: 0.75rem; }
}

/* ============================================================
   ANIMATIONS / UTILITIES
   ============================================================ */
.fade-in {
  animation: fadeSlideUp 0.5s ease both;
}

[data-delay="1"] { animation-delay: 0.05s; }
[data-delay="2"] { animation-delay: 0.1s; }
[data-delay="3"] { animation-delay: 0.15s; }
[data-delay="4"] { animation-delay: 0.2s; }
[data-delay="5"] { animation-delay: 0.25s; }
[data-delay="6"] { animation-delay: 0.3s; }
[data-delay="7"] { animation-delay: 0.35s; }
[data-delay="8"] { animation-delay: 0.4s; }