/* =========================================
   Investment Calculator - Modern CSS
   ========================================= */

/* CSS Variables */
:root {
  /* Colors */
  --color-primary: #6366f1;
  --color-primary-dark: #4f46e5;
  --color-primary-light: #818cf8;
  --color-primary-bg: rgba(99, 102, 241, 0.1);
  
  --color-success: #10b981;
  --color-success-dark: #059669;
  --color-success-light: #34d399;
  --color-success-bg: rgba(16, 185, 129, 0.1);
  
  --color-warning: #f59e0b;
  --color-warning-dark: #d97706;
  --color-warning-light: #fbbf24;
  --color-warning-bg: rgba(245, 158, 11, 0.1);
  
  --color-gold: #eab308;
  --color-gold-dark: #ca8a04;
  --color-gold-light: #facc15;
  
  --color-accent: #06b6d4;
  --color-accent-dark: #0891b2;
  
  /* Neutrals */
  --color-bg: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-bg-tertiary: #334155;
  --color-bg-card: #1e293b;
  --color-bg-input: #0f172a;
  
  --color-text: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  
  --color-border: #334155;
  --color-border-light: #475569;
  
  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  --gradient-success: linear-gradient(135deg, var(--color-success) 0%, var(--color-success-light) 100%);
  --gradient-gold: linear-gradient(135deg, var(--color-gold) 0%, var(--color-warning) 100%);
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
}

/* Light Mode */
@media (prefers-color-scheme: light) {
  :root {
    --color-bg: #f8fafc;
    --color-bg-secondary: #ffffff;
    --color-bg-tertiary: #f1f5f9;
    --color-bg-card: #ffffff;
    --color-bg-input: #f1f5f9;
    
    --color-text: #1e293b;
    --color-text-secondary: #475569;
    --color-text-muted: #94a3b8;
    
    --color-border: #e2e8f0;
    --color-border-light: #cbd5e1;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.15);
  }
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  overflow-x: hidden;
  width: 100%;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  width: 100%;
  max-width: 100%;
  padding: 0;
  margin: 0;
}

/* App Container */
.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  width: 100%;
  max-width: 100%;
  padding: 0;
}

/* Header */
.header {
  background: var(--gradient-primary);
  padding: var(--spacing-xl) var(--spacing-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.5;
}

.header-content {
  position: relative;
  z-index: 1;
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-lg);
  color: white;
}

.logo h1 {
  font-size: var(--text-2xl);
  font-weight: 700;
  color: white;
  letter-spacing: -0.025em;
}

.tagline {
  color: rgba(255, 255, 255, 0.9);
  font-size: var(--text-base);
  font-weight: 400;
}

/* Navigation Tabs */
.calculator-nav {
  display: flex;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-lg);
  background: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  flex-wrap: wrap;
}

.nav-tab {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  background: transparent;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  font-size: var(--text-base);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.nav-tab:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.nav-tab.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
  box-shadow: var(--shadow-glow);
}

.tab-icon {
  display: flex;
  align-items: center;
}

/* Format Toggle */
.format-toggle-container {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-left: auto;
  padding-left: var(--spacing-lg);
}

.format-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-weight: 500;
}

.format-toggle {
  display: flex;
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-md);
  padding: 2px;
  border: 1px solid var(--color-border);
}

.format-btn {
  padding: var(--spacing-xs) var(--spacing-md);
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

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

.format-btn.active {
  background: var(--color-primary);
  color: white;
}

/* Main Content */
.main {
  flex: 1;
  padding: var(--spacing-xl);
  max-width: 1400px;
  margin: 0 auto;
  width: 100%;
  overflow-x: hidden;
}

/* Calculator Panel */
.calculator-panel {
  display: none;
  animation: fadeIn 0.3s ease;
  width: 100%;
  max-width: 100%;
  overflow-x: hidden;
}

.calculator-panel.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.calculator-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
  width: 100%;
  max-width: 100%;
}

/* Calculator Inputs Section */
.calculator-inputs {
  background: var(--color-bg-card);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  width: 100%;
  max-width: 100%;
  overflow: hidden;
}

.calculator-title {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.title-icon {
  font-size: var(--text-2xl);
}

.calculator-description {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  margin-bottom: var(--spacing-xl);
}

/* Mode Toggle */
.mode-toggle-container {
  margin-bottom: var(--spacing-xl);
}

.mode-label,
.preserve-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.mode-toggle {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  background: var(--color-bg-input);
  padding: var(--spacing-xs);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
}

.mode-btn {
  flex: 1;
  min-width: fit-content;
  padding: var(--spacing-sm) var(--spacing-md);
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.mode-btn:hover {
  color: var(--color-text);
  background: var(--color-bg-tertiary);
}

.mode-btn.active {
  background: var(--color-primary);
  color: white;
  box-shadow: var(--shadow-sm);
}

/* Preserve Principal Toggle */
.preserve-toggle-container {
  margin-bottom: var(--spacing-xl);
}

.preserve-toggle {
  display: flex;
  gap: var(--spacing-md);
}

.preserve-btn {
  flex: 1;
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--color-bg-input);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: left;
}

.preserve-btn:hover {
  border-color: var(--color-primary-light);
}

.preserve-btn.active {
  border-color: var(--color-primary);
  background: var(--color-primary-bg);
}

.preserve-icon {
  font-size: var(--text-2xl);
}

.preserve-text {
  display: flex;
  flex-direction: column;
}

.preserve-text strong {
  font-size: var(--text-sm);
  color: var(--color-text);
}

.preserve-text small {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

/* Input Fields */
.input-field {
  margin-bottom: var(--spacing-xl);
  transition: opacity var(--transition-normal);
}

.input-field.hidden {
  display: none;
}

.input-field.highlighted {
  background: var(--color-primary-bg);
  margin: calc(var(--spacing-xl) * -1);
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  border: 2px solid var(--color-primary);
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { border-color: var(--color-primary); }
  50% { border-color: var(--color-primary-light); }
}

.field-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
  width: 100%;
  max-width: 100%;
  gap: var(--spacing-sm);
}

.field-header label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  flex: 1 1 auto;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
}

.field-value {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  flex: 0 0 auto;
  max-width: 50%;
}

.currency {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-primary);
}

.suffix {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
}

.value-input {
  background: var(--color-bg-input);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text);
  text-align: right;
  width: 160px;
  max-width: 40vw;
  transition: all var(--transition-fast);
  box-sizing: border-box;
}

.value-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-bg);
}

.value-input--small {
  width: 80px;
  max-width: 25vw;
}

/* Frequency Toggle */
.frequency-toggle {
  display: flex;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-md);
  background: var(--color-bg-input);
  padding: var(--spacing-xs);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.freq-btn {
  flex: 1;
  padding: var(--spacing-sm);
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.freq-btn.active {
  background: var(--color-primary);
  color: white;
}

/* Preset Amount Buttons */
.preset-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-sm);
}

.preset-btn {
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--color-bg-input);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  color: var(--color-text-secondary);
  font-size: var(--text-xs);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

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

.preset-btn.active {
  background: var(--color-primary-bg);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* Slider Styles */
.slider-wrapper {
  position: relative;
}

.slider {
  width: 100%;
  height: 8px;
  background: var(--color-bg-tertiary);
  border-radius: var(--radius-full);
  outline: none;
  cursor: pointer;
  -webkit-appearance: none;
  appearance: none;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  background: var(--color-primary);
  border-radius: 50%;
  cursor: pointer;
  border: 4px solid var(--color-bg-card);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-fast);
}

.slider::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

.slider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  background: var(--color-primary);
  border-radius: 50%;
  cursor: pointer;
  border: 4px solid var(--color-bg-card);
  box-shadow: var(--shadow-md);
}

.slider--accent::-webkit-slider-thumb {
  background: var(--color-accent);
}

.slider--accent::-moz-range-thumb {
  background: var(--color-accent);
}

.slider--success::-webkit-slider-thumb {
  background: var(--color-success);
}

.slider--success::-moz-range-thumb {
  background: var(--color-success);
}

.slider--warning::-webkit-slider-thumb {
  background: var(--color-warning);
}

.slider--warning::-moz-range-thumb {
  background: var(--color-warning);
}

.slider--gold::-webkit-slider-thumb {
  background: var(--color-gold);
}

.slider--gold::-moz-range-thumb {
  background: var(--color-gold);
}

.slider-range {
  display: flex;
  justify-content: space-between;
  margin-top: var(--spacing-xs);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  width: 100%;
  max-width: 100%;
  overflow: hidden;
}

.slider-range span {
  max-width: 45%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Results Section */
.calculator-results {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
  width: 100%;
  max-width: 100%;
  overflow: hidden;
}

.results-card {
  background: var(--color-bg-card);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  width: 100%;
  max-width: 100%;
  overflow: hidden;
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
}

.result-item--highlight {
  background: var(--gradient-primary);
  margin: calc(var(--spacing-xl) * -1);
  margin-bottom: var(--spacing-lg);
  padding: var(--spacing-xl);
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
}

.result-item--highlight .result-label {
  color: rgba(255, 255, 255, 0.9);
  font-weight: 500;
}

.result-item--highlight .result-value {
  color: white;
  font-size: var(--text-3xl);
  font-weight: 700;
}

.result-label {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.result-value {
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-text);
}

.result-value--secondary {
  color: var(--color-text-secondary);
}

.result-value--success {
  color: var(--color-success);
}

.result-value--warning {
  color: var(--color-warning);
}

.result-breakdown {
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-md);
}


.result-info {
  padding: var(--spacing-md);
  background: var(--color-bg-input);
  border-radius: var(--radius-md);
  margin-top: var(--spacing-md);
  font-size: var(--text-sm);
  text-align: center;
}

.result-info.success {
  background: var(--color-success-bg);
  color: var(--color-success);
}

/* Share Button */
.share-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  width: 100%;
  padding: var(--spacing-md);
  margin-top: var(--spacing-md);
  background: var(--color-bg-input);
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-md);
  color: var(--color-primary);
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.share-btn:hover {
  background: var(--color-primary);
  color: white;
}

.share-btn:active {
  transform: scale(0.98);
}

.share-btn svg {
  flex-shrink: 0;
}

.result-info.warning {
  background: var(--color-warning-bg);
  color: var(--color-warning);
}

.result-info.error {
  background: rgba(239, 68, 68, 0.1);
  color: #ef4444;
}

/* Chart Card */
.chart-card {
  background: var(--color-bg-card);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  flex: 1;
}

.chart-title {
  font-size: var(--text-base);
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

.chart-container {
  position: relative;
  height: 280px;
}

/* Footer */
.footer {
  background: var(--color-bg-secondary);
  padding: var(--spacing-xl);
  border-top: 1px solid var(--color-border);
  text-align: center;
}

.footer-note {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto var(--spacing-md);
}

.footer-copyright {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

/* Toast */
.toast {
  position: fixed;
  bottom: var(--spacing-xl);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-success);
  color: white;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--text-sm);
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: all var(--transition-normal);
  z-index: 1000;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Responsive Design */

/* Tablet Portrait and below */
@media (max-width: 1024px) {
  .calculator-container {
    grid-template-columns: 1fr;
  }
  
  .preserve-toggle {
    flex-direction: column;
  }
  
  .calculator-nav {
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
  }
  
  .format-toggle-container {
    margin-left: 0;
    padding-left: 0;
  }
}

/* Tablet and Mobile */
@media (max-width: 768px) {
  :root {
    /* Larger font sizes for better readability */
    --text-xs: 0.875rem;
    --text-sm: 1rem;
    --text-base: 1.1rem;
    --text-lg: 1.2rem;
    --text-xl: 1.35rem;
    --text-2xl: 1.6rem;
    --text-3xl: 1.9rem;
  }
  
  /* Prevent horizontal overflow - global fix */
  html, body {
    overflow-x: hidden !important;
    width: 100% !important;
    max-width: 100vw !important;
  }
  
  * {
    box-sizing: border-box;
  }
  
  .app {
    width: 100%;
    max-width: 100vw;
    overflow-x: hidden;
  }
  
  .main {
    padding: var(--spacing-md);
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
  }
  
  .calculator-panel,
  .calculator-container,
  .calculator-inputs,
  .calculator-results,
  .results-card,
  .chart-card,
  .input-field,
  .field-header,
  .slider-wrapper,
  .result-item,
  .result-breakdown {
    max-width: 100%;
    width: 100%;
    overflow-x: hidden;
  }
  
  /* Header - ensure visibility */
  .header {
    padding: var(--spacing-sm);
    min-height: 70px;
    width: 100%;
    max-width: 100vw;
  }
  
  .header-content {
    position: relative;
    z-index: 2;
  }
  
  .logo {
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .logo-icon {
    width: 36px;
    height: 36px;
  }
  
  .logo-icon svg {
    width: 24px;
    height: 24px;
  }
  
  .logo h1 {
    font-size: var(--text-lg);
  }
  
  .tagline {
    font-size: var(--text-sm);
  }
  
  /* Navigation - stack vertically */
  .calculator-nav {
    padding: var(--spacing-xs);
    gap: var(--spacing-xs);
    flex-direction: column;
    align-items: stretch;
    width: 100%;
    max-width: 100%;
  }
  
  .nav-tab {
    padding: var(--spacing-sm);
    font-size: var(--text-sm);
    justify-content: center;
    flex: none;
    max-width: none;
    border-radius: var(--radius-md);
  }
  
  .nav-tab .tab-icon {
    display: none;
  }
  
  .format-toggle-container {
    width: 100%;
    justify-content: center;
    margin-left: 0;
    padding-left: 0;
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--color-border);
  }
  
  .main {
    padding: var(--spacing-sm);
  }
  
  .calculator-inputs,
  .results-card,
  .chart-card {
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    width: 100%;
    box-sizing: border-box;
  }
  
  .calculator-title {
    font-size: var(--text-base);
    flex-wrap: wrap;
  }
  
  .title-icon {
    font-size: var(--text-lg);
  }
  
  .calculator-description {
    font-size: var(--text-xs);
    margin-bottom: var(--spacing-md);
  }
  
  .mode-toggle-container,
  .preserve-toggle-container {
    margin-bottom: var(--spacing-md);
  }
  
  /* Mode toggle - 2x2 grid with larger touch targets */
  .mode-toggle {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    width: 100%;
  }
  
  .mode-btn {
    flex: none;
    text-align: center;
    padding: var(--spacing-md);
    font-size: var(--text-sm);
    white-space: nowrap;
    min-height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 500;
  }
  
  .preserve-toggle {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .preserve-btn {
    padding: var(--spacing-sm);
    gap: var(--spacing-sm);
    min-height: 50px;
  }
  
  .preserve-icon {
    font-size: var(--text-lg);
  }
  
  .preserve-text strong {
    font-size: var(--text-xs);
  }
  
  .preserve-text small {
    font-size: 0.65rem;
  }
  
  .input-field {
    margin-bottom: var(--spacing-md);
    width: 100%;
  }
  
  .input-field.highlighted {
    margin: calc(var(--spacing-md) * -1);
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md);
  }
  
  /* Input fields - ROW layout for compact mobile view */
  .field-header {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    width: 100%;
  }
  
  .field-header label {
    font-size: var(--text-sm);
    font-weight: 600;
    flex: 1;
    min-width: 0;
  }
  
  .field-value {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    flex: 0 0 auto;
  }
  
  .value-input {
    width: 100px;
    padding: var(--spacing-sm) var(--spacing-sm);
    font-size: var(--text-base);
    text-align: right;
    min-height: 44px;
  }
  
  .value-input--small {
    width: 60px;
  }
  
  .currency {
    font-size: var(--text-base);
    font-weight: 600;
  }
  
  .suffix {
    font-size: var(--text-sm);
    white-space: nowrap;
    font-weight: 500;
  }
  
  /* Frequency toggle above input */
  .frequency-toggle {
    margin-bottom: var(--spacing-sm);
    margin-top: 0;
  }
  
  /* Slider wrapper */
  .slider-wrapper {
    width: 100%;
    max-width: 100%;
    overflow: hidden;
  }
  
  .slider-range {
    width: 100%;
    max-width: 100%;
    overflow: hidden;
  }
  
  .slider-range span {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  
  /* Make sliders more touch-friendly */
  .slider {
    height: 12px;
    width: 100%;
  }
  
  .slider::-webkit-slider-thumb {
    width: 32px;
    height: 32px;
    border-width: 3px;
  }
  
  .slider::-moz-range-thumb {
    width: 32px;
    height: 32px;
    border-width: 3px;
  }
  
  .slider-range {
    font-size: var(--text-xs);
    margin-top: var(--spacing-sm);
  }
  
  .frequency-toggle {
    margin-top: var(--spacing-md);
    width: 100%;
  }
  
  .freq-btn {
    padding: var(--spacing-md);
    font-size: var(--text-sm);
    min-height: 48px;
    font-weight: 500;
  }
  
  /* Results Section Mobile */
  .results-card {
    padding: var(--spacing-md);
    padding-top: 0;
    overflow: hidden;
    border-radius: var(--radius-lg);
  }
  
  .result-item--highlight {
    margin-left: calc(-1 * var(--spacing-md));
    margin-right: calc(-1 * var(--spacing-md));
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: auto;
    box-sizing: border-box;
  }
  
  .result-item--highlight .result-label {
    font-size: var(--text-sm);
    font-weight: 600;
  }
  
  .result-item--highlight .result-value {
    font-size: var(--text-xl);
    font-weight: 700;
  }
  
  .result-breakdown {
    padding-top: var(--spacing-xs);
  }
  
  .result-item {
    padding: var(--spacing-xs) 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-sm);
  }
  
  .result-label {
    font-size: var(--text-sm);
    flex: 1;
    min-width: 0;
  }
  
  .result-value {
    font-size: var(--text-sm);
    flex-shrink: 0;
    text-align: right;
    font-weight: 600;
  }
  
  .result-info {
    padding: var(--spacing-sm);
    font-size: var(--text-sm);
    margin-top: var(--spacing-sm);
  }
  
  .chart-title {
    font-size: var(--text-sm);
    margin-bottom: var(--spacing-md);
  }
  
  /* Square chart for mobile */
  .chart-container {
    height: 280px;
    width: 100%;
    aspect-ratio: 1 / 1;
    max-height: 350px;
  }
  
  .footer {
    padding: var(--spacing-md);
  }
  
  .footer-note {
    font-size: var(--text-xs);
  }
  
  .footer-copyright {
    font-size: 0.65rem;
  }
}

/* Mobile Small */
@media (max-width: 480px) {
  :root {
    /* Still readable font sizes for smaller screens */
    --text-xs: 0.8rem;
    --text-sm: 0.9rem;
    --text-base: 1rem;
    --text-lg: 1.1rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.75rem;
  }
  
  .header {
    padding: var(--spacing-sm);
    min-height: 70px;
  }
  
  .logo-icon {
    width: 30px;
    height: 30px;
  }
  
  .logo-icon svg {
    width: 18px;
    height: 18px;
  }
  
  .logo h1 {
    font-size: var(--text-base);
  }
  
  .tagline {
    font-size: var(--text-xs);
  }
  
  .calculator-nav {
    padding: var(--spacing-xs);
    gap: var(--spacing-xs);
  }
  
  .nav-tab {
    padding: var(--spacing-sm);
    font-size: var(--text-xs);
    border-width: 1px;
    min-height: 44px;
  }
  
  .format-toggle-container {
    padding-top: var(--spacing-xs);
  }
  
  .format-toggle {
    padding: 2px;
  }
  
  .format-btn {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--text-xs);
    min-height: 36px;
  }
  
  .format-label {
    font-size: var(--text-xs);
  }
  
  .main {
    padding: var(--spacing-xs);
  }
  
  .calculator-inputs,
  .results-card,
  .chart-card {
    padding: var(--spacing-sm);
    border-radius: var(--radius-md);
    width: 100%;
  }
  
  .calculator-title {
    font-size: var(--text-sm);
    gap: var(--spacing-xs);
  }
  
  .title-icon {
    font-size: var(--text-base);
  }
  
  .calculator-description {
    font-size: 0.65rem;
    margin-bottom: var(--spacing-sm);
  }
  
  .mode-toggle-container,
  .preserve-toggle-container {
    margin-bottom: var(--spacing-sm);
  }
  
  .mode-label,
  .preserve-label {
    font-size: var(--text-xs);
    margin-bottom: var(--spacing-xs);
  }
  
  /* Mode toggle - 2x2 grid with good touch targets */
  .mode-toggle {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs);
    width: 100%;
  }
  
  .mode-btn {
    padding: var(--spacing-sm);
    font-size: var(--text-sm);
    min-height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .preserve-btn {
    padding: var(--spacing-sm);
    gap: var(--spacing-xs);
    border-width: 1px;
    min-height: 52px;
  }
  
  .preserve-icon {
    font-size: var(--text-lg);
  }
  
  .preserve-text strong {
    font-size: var(--text-sm);
  }
  
  .preserve-text small {
    display: none;
  }
  
  .input-field {
    margin-bottom: var(--spacing-md);
    width: 100%;
  }
  
  .input-field.highlighted {
    margin: calc(var(--spacing-sm) * -1);
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm);
    border-width: 1px;
  }
  
  .field-header {
    margin-bottom: var(--spacing-xs);
  }
  
  .field-header label {
    font-size: var(--text-sm);
  }
  
  .value-input {
    width: 90px;
    padding: var(--spacing-sm);
    font-size: var(--text-sm);
    border-width: 1px;
    min-height: 40px;
  }
  
  .value-input--small {
    width: 55px;
  }
  
  .currency {
    font-size: var(--text-sm);
  }
  
  .suffix {
    font-size: var(--text-xs);
  }
  
  /* Preset buttons smaller on mobile */
  .preset-btn {
    padding: var(--spacing-xs);
    font-size: 0.7rem;
  }
  
  .slider {
    height: 10px;
  }
  
  .slider::-webkit-slider-thumb {
    width: 28px;
    height: 28px;
  }
  
  .slider::-moz-range-thumb {
    width: 28px;
    height: 28px;
  }
  
  .slider-range {
    font-size: var(--text-xs);
  }
  
  .frequency-toggle {
    padding: 3px;
    width: 100%;
  }
  
  .freq-btn {
    padding: var(--spacing-sm);
    font-size: var(--text-sm);
    min-height: 44px;
  }
  
  /* Results Mobile Small */
  .results-card {
    padding: var(--spacing-sm);
    padding-top: 0;
  }
  
  .result-item--highlight {
    margin-left: calc(-1 * var(--spacing-sm));
    margin-right: calc(-1 * var(--spacing-sm));
    margin-top: 0;
    margin-bottom: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    width: auto;
  }
  
  .result-item--highlight .result-label {
    font-size: var(--text-sm);
  }
  
  .result-item--highlight .result-value {
    font-size: var(--text-lg);
  }
  
  .result-breakdown {
    padding-top: var(--spacing-sm);
  }
  
  .result-item {
    padding: var(--spacing-sm) 0;
  }
  
  .result-label {
    font-size: var(--text-sm);
  }
  
  .result-value {
    font-size: var(--text-base);
  }
  
  .result-info {
    padding: var(--spacing-sm);
    font-size: var(--text-sm);
  }
  
  .chart-title {
    font-size: var(--text-xs);
    margin-bottom: var(--spacing-sm);
  }
  
  .chart-container {
    height: 250px;
    width: 100%;
    aspect-ratio: 1 / 1;
    max-height: 300px;
  }
  
  .footer {
    padding: var(--spacing-sm);
  }
  
  .footer-note {
    font-size: 0.6rem;
    margin-bottom: var(--spacing-xs);
  }
  
  .footer-copyright {
    font-size: 0.55rem;
  }
  
  .toast {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--text-xs);
    bottom: var(--spacing-sm);
  }
}

/* Extra small devices */
@media (max-width: 360px) {
  .logo h1 {
    font-size: var(--text-base);
  }
  
  .nav-tab {
    padding: var(--spacing-xs);
    font-size: 0.6rem;
  }
  
  .mode-btn {
    font-size: 0.6rem;
  }
  
  .value-input {
    width: 85px;
    font-size: var(--text-xs);
  }
  
  .value-input--small {
    width: 50px;
  }
  
  .result-item--highlight .result-value {
    font-size: var(--text-lg);
  }
  
  .chart-container {
    height: 160px;
  }
}

/* Landscape orientation for mobile */
@media (max-width: 768px) and (orientation: landscape) {
  .header {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  .logo-icon {
    width: 32px;
    height: 32px;
  }
  
  .tagline {
    display: none;
  }
  
  .calculator-nav {
    flex-direction: row;
    flex-wrap: wrap;
  }
  
  .format-toggle-container {
    border-top: none;
    padding-top: 0;
  }
  
  .chart-container {
    height: 180px;
  }
}

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

/* Screen Reader Only */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Animation Utilities */
.updated {
  animation: highlightUpdate 0.3s ease;
}

@keyframes highlightUpdate {
  0% { transform: scale(1); }
  50% { transform: scale(1.02); }
  100% { transform: scale(1); }
}

/* Print Styles */
@media print {
  .header,
  .calculator-nav,
  .footer,
  .slider-wrapper {
    display: none;
  }
  
  .calculator-container {
    display: block;
  }
  
  .calculator-inputs,
  .results-card,
  .chart-card {
    box-shadow: none;
    border: 1px solid #ddd;
    page-break-inside: avoid;
    margin-bottom: 1rem;
  }
}