/* ==========================================================================
   Accumeasure v2.0 - Mobile-First Responsive CSS System
   ========================================================================== */

/* CSS Custom Properties (Variables) */
:root {
  /* Colors - Enhanced Light Mode */
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-primary-light: #60a5fa;
  --color-secondary: #8b5cf6;
  --color-accent: #06b6d4;
  
  --color-text: #0f172a;
  --color-text-secondary: #475569;
  --color-text-muted: #64748b;
  --color-text-inverse: #ffffff;
  
  --color-bg: #ffffff;
  --color-bg-secondary: #fafbfc;
  --color-bg-tertiary: #f3f4f6;
  --color-bg-elevated: #ffffff;
  --color-bg-glass: rgba(255, 255, 255, 0.85);
  
  --color-border: #e5e7eb;
  --color-border-secondary: #d1d5db;
  --color-border-focus: #60a5fa;
  
  --color-success: #10b981;
  --color-success-bg: #d1fae5;
  --color-warning: #f59e0b;
  --color-warning-bg: #fef3c7;
  --color-error: #ef4444;
  --color-error-bg: #fee2e2;
  --color-info: #06b6d4;
  --color-info-bg: #cffafe;
  
  /* Interactive States - Enhanced */
  --color-hover: rgba(59, 130, 246, 0.1);
  --color-active: rgba(59, 130, 246, 0.15);
  --color-focus: rgba(59, 130, 246, 0.25);
  
  /* Dark Mode Colors - Enhanced for Readability */
  --color-dark-primary: #60a5fa;
  --color-dark-primary-dark: #3b82f6;
  --color-dark-primary-light: #93c5fd;
  
  --color-dark-text: #ffffff;
  --color-dark-text-secondary: #e2e8f0;
  --color-dark-text-muted: #cbd5e1;
  --color-dark-text-inverse: #0f172a;
  
  --color-dark-bg: #0a0f1c;
  --color-dark-bg-secondary: #1a202c;
  --color-dark-bg-tertiary: #2d3748;
  --color-dark-bg-elevated: #1a202c;
  --color-dark-bg-glass: rgba(10, 15, 28, 0.95);
  
  --color-dark-border: #4a5568;
  --color-dark-border-secondary: #718096;
  --color-dark-border-focus: #60a5fa;
  
  --color-dark-success: #48cc80;
  --color-dark-success-bg: rgba(72, 204, 128, 0.15);
  --color-dark-warning: #ffd93d;
  --color-dark-warning-bg: rgba(255, 217, 61, 0.15);
  --color-dark-error: #ff7979;
  --color-dark-error-bg: rgba(255, 121, 121, 0.15);
  --color-dark-info: #4db8ff;
  --color-dark-info-bg: rgba(77, 184, 255, 0.15);
  
  /* Dark Interactive States - Enhanced Visibility */
  --color-dark-hover: rgba(96, 165, 250, 0.18);
  --color-dark-active: rgba(96, 165, 250, 0.25);
  --color-dark-focus: rgba(96, 165, 250, 0.35);
  
  /* Spacing */
  --space-xs: 0.25rem;   /* 4px */
  --space-sm: 0.5rem;    /* 8px */
  --space-md: 1rem;      /* 16px */
  --space-lg: 1.5rem;    /* 24px */
  --space-xl: 2rem;      /* 32px */
  --space-2xl: 3rem;     /* 48px */
  --space-3xl: 4rem;     /* 64px */
  
  /* Typography */
  --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  
  --font-size-xs: 0.75rem;   /* 12px */
  --font-size-sm: 0.875rem;  /* 14px */
  --font-size-md: 1rem;      /* 16px */
  --font-size-lg: 1.125rem;  /* 18px */
  --font-size-xl: 1.25rem;   /* 20px */
  --font-size-2xl: 1.5rem;   /* 24px */
  --font-size-3xl: 1.875rem; /* 30px */
  --font-size-4xl: 2.25rem;  /* 36px */
  
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Layout */
  --container-max-width: 1200px;
  --header-height: 60px;
  
  /* Border Radius */
  --radius-sm: 0.125rem;  /* 2px */
  --radius-md: 0.25rem;   /* 4px */
  --radius-lg: 0.5rem;    /* 8px */
  --radius-xl: 0.75rem;   /* 12px */
  
  /* Enhanced Shadows for Light Mode */
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.08), 0 1px 2px 0 rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 8px -2px rgba(0, 0, 0, 0.12), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 12px 24px -4px rgba(0, 0, 0, 0.15), 0 8px 16px -4px rgba(0, 0, 0, 0.08);
  --shadow-xl: 0 20px 40px -8px rgba(0, 0, 0, 0.18), 0 16px 32px -8px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.2);
  --shadow-glow-lg: 0 0 40px rgba(59, 130, 246, 0.25);
  
  /* Dark Mode Enhanced Shadows */
  --shadow-dark-sm: 0 2px 4px 0 rgba(0, 0, 0, 0.4);
  --shadow-dark-md: 0 6px 12px -2px rgba(0, 0, 0, 0.5), 0 4px 8px -2px rgba(0, 0, 0, 0.3);
  --shadow-dark-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Z-index */
  --z-dropdown: 1000;
  --z-modal: 1050;
  --z-overlay: 1040;
  --z-header: 1030;
}

/* Dark Mode Variables */
[data-theme="dark"] {
  /* Primary Colors */
  --color-primary: var(--color-dark-primary);
  --color-primary-dark: var(--color-dark-primary-dark);
  --color-primary-light: var(--color-dark-primary-light);
  
  /* Text Colors */
  --color-text: var(--color-dark-text);
  --color-text-secondary: var(--color-dark-text-secondary);
  --color-text-muted: var(--color-dark-text-muted);
  --color-text-inverse: var(--color-dark-text-inverse);
  
  /* Background Colors */
  --color-bg: var(--color-dark-bg);
  --color-bg-secondary: var(--color-dark-bg-secondary);
  --color-bg-tertiary: var(--color-dark-bg-tertiary);
  --color-bg-elevated: var(--color-dark-bg-elevated);
  --color-bg-glass: var(--color-dark-bg-glass);
  
  /* Border Colors */
  --color-border: var(--color-dark-border);
  --color-border-secondary: var(--color-dark-border-secondary);
  --color-border-focus: var(--color-dark-border-focus);
  
  /* Status Colors */
  --color-success: var(--color-dark-success);
  --color-success-bg: var(--color-dark-success-bg);
  --color-warning: var(--color-dark-warning);
  --color-warning-bg: var(--color-dark-warning-bg);
  --color-error: var(--color-dark-error);
  --color-error-bg: var(--color-dark-error-bg);
  --color-info: var(--color-dark-info);
  --color-info-bg: var(--color-dark-info-bg);
  
  /* Interactive States */
  --color-hover: var(--color-dark-hover);
  --color-active: var(--color-dark-active);
  --color-focus: var(--color-dark-focus);
  
  /* Enhanced Shadows for Dark Mode */
  --shadow-sm: var(--shadow-dark-sm);
  --shadow-md: var(--shadow-dark-md);
  --shadow-lg: var(--shadow-dark-lg);
}

/* ==========================================================================
   Reset & Base Styles
   ========================================================================== */

/* Box sizing reset */
*, *::before, *::after {
  box-sizing: border-box;
}

/* Remove default margins */
* {
  margin: 0;
  padding: 0;
}

/* HTML & Body */
html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  /* Beautiful gradient background with visible pattern */
  background: 
    radial-gradient(circle at 1px 1px, rgba(59, 130, 246, 0.15) 1px, transparent 0),
    linear-gradient(135deg, 
      #f1f5f9 0%, 
      #e2e8f0 25%, 
      #cbd5e1 50%, 
      #e2e8f0 75%, 
      #f1f5f9 100%
    );
  background-size: 20px 20px, 400% 400%;
  background-attachment: fixed;
  animation: gradientShift 20s ease infinite;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: color var(--transition-normal), background var(--transition-normal);
}

/* Enhanced font rendering for dark mode */
[data-theme="dark"] body {
  -webkit-font-smoothing: subpixel-antialiased;
  -moz-osx-font-smoothing: auto;
  /* Dark theme gradient background with subtle pattern */
  background: 
    radial-gradient(circle at 1px 1px, rgba(96, 165, 250, 0.12) 1px, transparent 0),
    linear-gradient(135deg, 
      #0f172a 0%, 
      #1e293b 25%, 
      #334155 50%, 
      #1e293b 75%, 
      #0f172a 100%
    );
  background-size: 20px 20px, 400% 400%;
  background-attachment: fixed;
  animation: gradientShift 25s ease infinite;
}

/* ==========================================================================
   Typography
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-md); }

p {
  margin-bottom: var(--space-md);
  color: var(--color-text-secondary);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* ==========================================================================
   Layout Components
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* Mobile-first breakpoints */
@media (min-width: 480px) {
  .container {
    padding: 0 var(--space-lg);
  }
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--space-xl);
  }
}

@media (min-width: 1024px) {
  .container {
    padding: 0 var(--space-2xl);
  }
}

/* ==========================================================================
   Header & Navigation - Modern & Simplistic
   ========================================================================== */

.header {
  background: linear-gradient(135deg, 
    rgba(255, 255, 255, 0.98) 0%, 
    rgba(248, 250, 252, 0.96) 50%, 
    rgba(241, 245, 249, 0.94) 100%
  );
  backdrop-filter: blur(24px) saturate(200%);
  -webkit-backdrop-filter: blur(24px) saturate(200%);
  border-bottom: 2px solid rgba(148, 163, 184, 0.2);
  box-shadow: 
    0 1px 3px rgba(0, 0, 0, 0.05),
    0 8px 32px rgba(0, 0, 0, 0.08),
    0 0 0 1px rgba(255, 255, 255, 0.8);
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  height: 64px;
  transition: all var(--transition-normal);
  /* Performance enhancements */
  will-change: transform;
  transform: translateZ(0); /* Enable GPU acceleration */
  -webkit-transform: translateZ(0);
}

.header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, 
    rgba(59, 130, 246, 0.04) 0%, 
    rgba(16, 185, 129, 0.02) 50%, 
    rgba(139, 92, 246, 0.03) 100%
  );
  pointer-events: none;
}

[data-theme="dark"] .header {
  background: linear-gradient(135deg, 
    rgba(3, 7, 18, 0.98) 0%, 
    rgba(15, 23, 42, 0.96) 30%, 
    rgba(30, 41, 59, 0.94) 70%, 
    rgba(51, 65, 85, 0.92) 100%
  );
  backdrop-filter: blur(28px) saturate(200%);
  -webkit-backdrop-filter: blur(28px) saturate(200%);
  border-bottom: 2px solid rgba(96, 165, 250, 0.3);
  box-shadow: 
    0 1px 3px rgba(0, 0, 0, 0.4),
    0 8px 32px rgba(0, 0, 0, 0.7),
    0 0 0 1px rgba(96, 165, 250, 0.15),
    inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

[data-theme="dark"] .header::before {
  background: linear-gradient(135deg, 
    rgba(96, 165, 250, 0.08) 0%, 
    rgba(52, 211, 153, 0.04) 30%, 
    rgba(139, 92, 246, 0.06) 70%, 
    rgba(59, 130, 246, 0.05) 100%
  );
}

.nav {
  height: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  position: relative;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  transition: transform var(--transition-fast);
}

.nav-brand:hover {
  transform: translateY(-1px);
}

.brand-title {
  font-size: var(--font-size-xl);
  font-weight: 800;
  background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 50%, #1e40af 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin: 0;
  line-height: 1;
  letter-spacing: -0.02em;
  position: relative;
  z-index: 1;
  filter: drop-shadow(0 1px 2px rgba(37, 99, 235, 0.2));
}

/* Enhanced brand visibility in dark mode */
[data-theme="dark"] .brand-title {
  background: linear-gradient(135deg, #60a5fa 0%, #3b82f6 50%, #2563eb 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  /* Removed glow effect for better readability */
  filter: none;
}

.brand-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1;
  font-weight: var(--font-weight-medium);
  opacity: 0.8;
}

/* Mobile Navigation Toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 48px;
  height: 48px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
  border-radius: 12px;
  transition: all var(--transition-fast);
  position: relative;
  /* Better mobile experience */
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  /* Prevent text selection/highlighting */
  user-select: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
}

.nav-toggle:hover, .nav-toggle:focus {
  background-color: var(--color-bg-secondary);
  transform: translateY(-1px);
}

.nav-toggle:active {
  transform: scale(0.98);
}

.hamburger-line {
  width: 22px;
  height: 2.5px;
  background-color: var(--color-text);
  margin: 2.5px 0;
  transition: all var(--transition-normal);
  border-radius: 2px;
  transform-origin: center;
  /* Prevent selection */
  user-select: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  pointer-events: none; /* Lines shouldn't be interactive */
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6px);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
  transform: scale(0);
}

.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

/* Dark Mode Navigation Toggle */
[data-theme="dark"] .nav-toggle {
  background: linear-gradient(135deg, 
    rgba(96, 165, 250, 0.2) 0%, 
    rgba(59, 130, 246, 0.15) 100%
  );
  border: 1px solid rgba(96, 165, 250, 0.4);
  box-shadow: 
    var(--shadow-sm),
    0 0 0 1px rgba(255, 255, 255, 0.1),
    inset 0 1px 0 rgba(255, 255, 255, 0.15);
}

[data-theme="dark"] .nav-toggle:hover, 
[data-theme="dark"] .nav-toggle:focus {
  background: linear-gradient(135deg, 
    rgba(96, 165, 250, 0.3) 0%, 
    rgba(59, 130, 246, 0.25) 100%
  );
  border-color: rgba(96, 165, 250, 0.6);
  box-shadow: 
    var(--shadow-md),
    0 0 12px rgba(96, 165, 250, 0.3),
    inset 0 1px 0 rgba(255, 255, 255, 0.2);
  transform: translateY(-2px);
}

[data-theme="dark"] .hamburger-line {
  background: linear-gradient(135deg, #ffffff 0%, #e2e8f0 100%);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* Navigation Menu */
.nav-menu {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  left: var(--space-md);
  right: var(--space-md);
  background-color: var(--color-bg-glass);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.15), 0 10px 10px -5px rgba(0, 0, 0, 0.1);
  list-style: none;
  padding: var(--space-md);
  margin: 0;
  animation: slideDown 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] .nav-menu {
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.8), 0 15px 25px -10px rgba(0, 0, 0, 0.6);
  border-color: var(--color-dark-border-secondary);
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.nav-menu.active {
  display: block;
}

.nav-item {
  margin: 0;
}

.nav-link {
  display: block;
  padding: var(--space-sm) var(--space-md);
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  border-radius: 10px;
  margin-bottom: var(--space-xs);
  transition: all var(--transition-fast);
  position: relative;
}

.nav-link:hover, .nav-link:focus {
  background-color: var(--color-hover);
  color: var(--color-primary);
  text-decoration: none;
  transform: translateX(4px);
  box-shadow: var(--shadow-sm);
}

.nav-link.active {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  box-shadow: var(--shadow-md);
}

/* Theme Toggle - Modern Animated */
.theme-toggle {
  display: flex;
  align-items: center;
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  background: none;
  border: none;
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
  cursor: pointer;
  text-align: left;
  border-radius: 12px;
  margin-bottom: var(--space-xs);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
  /* Better mobile experience */
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

/* Nav Menu Theme Icon Switching Logic handled by opacity above */

.theme-toggle::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.05), transparent);
  transition: left var(--transition-slow);
  opacity: 0.8;
}

.theme-toggle:hover::before {
  left: 100%;
}

.theme-toggle:hover, .theme-toggle:focus {
  background-color: var(--color-hover);
  color: var(--color-primary);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.theme-toggle:active {
  transform: translateY(0) scale(0.98);
}

/* Theme Toggle Container */
.theme-toggle-container {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* Animated Theme Icon Container */
.theme-icon-container {
  position: relative;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-icon {
  font-size: var(--font-size-lg);
  transition: all var(--transition-normal);
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

/* Icon visibility based on theme */
[data-theme="light"] .theme-icon.moon,
.theme-icon.moon {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1) rotate(0deg);
}

[data-theme="light"] .theme-icon.sun,
.theme-icon.sun {
  opacity: 0;
  transform: translate(-50%, -50%) scale(0.5) rotate(-90deg);
}

[data-theme="dark"] .theme-icon.moon {
  opacity: 0;
  transform: translate(-50%, -50%) scale(0.5) rotate(90deg);
}

[data-theme="dark"] .theme-icon.sun {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1) rotate(0deg);
}

/* Hover effects */
.theme-toggle:hover .theme-icon.moon {
  transform: translate(-50%, -50%) rotate(5deg);
}

.theme-toggle:hover .theme-icon.sun {
  transform: translate(-50%, -50%) rotate(5deg);
}

[data-theme="dark"] .theme-toggle:hover .theme-icon.sun {
  transform: translate(-50%, -50%) rotate(5deg);
}

[data-theme="dark"] .theme-toggle:hover .theme-icon.moon {
  transform: translate(-50%, -50%) rotate(5deg);
}

/* Theme toggle text */
.theme-toggle-text {
  font-size: var(--font-size-sm);
  opacity: 0.9;
  transition: opacity var(--transition-fast);
}

.theme-toggle:hover .theme-toggle-text {
  opacity: 1;
}

/* Dark Mode Theme Toggle */
[data-theme="dark"] .theme-toggle {
  background: linear-gradient(135deg, 
    rgba(96, 165, 250, 0.18) 0%, 
    rgba(59, 130, 246, 0.12) 100%
  );
  border: 1px solid rgba(96, 165, 250, 0.4);
  color: var(--color-text);
  box-shadow: 
    var(--shadow-sm),
    0 0 0 1px rgba(255, 255, 255, 0.08),
    inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

[data-theme="dark"] .theme-toggle:hover, 
[data-theme="dark"] .theme-toggle:focus {
  background: linear-gradient(135deg, 
    rgba(96, 165, 250, 0.2) 0%, 
    rgba(59, 130, 246, 0.15) 100%
  );
  color: var(--color-primary);
  box-shadow: 0 2px 8px rgba(96, 165, 250, 0.15);
  transform: translateY(-1px);
}

/* Animation keyframes */
@keyframes iconBounce {
  0% { transform: scale(1) rotate(0deg); }
  25% { transform: scale(0.8) rotate(-10deg); }
  50% { transform: scale(1.2) rotate(5deg); }
  75% { transform: scale(0.95) rotate(-2deg); }
  100% { transform: scale(1) rotate(0deg); }
}

/* Gradient shift animation for background */
@keyframes gradientShift {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}

/* Smooth theme transitions */
* {
  transition: background-color var(--transition-normal), 
              color var(--transition-normal), 
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
}

/* Mobile Header Enhancements */
@media (max-width: 767px) {
  .header {
    background: linear-gradient(135deg, 
      rgba(255, 255, 255, 0.99) 0%, 
      rgba(248, 250, 252, 0.97) 50%, 
      rgba(241, 245, 249, 0.95) 100%
    );
    backdrop-filter: blur(28px) saturate(200%);
    -webkit-backdrop-filter: blur(28px) saturate(200%);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.08), 
      0 8px 32px rgba(0, 0, 0, 0.12),
      0 0 0 1px rgba(255, 255, 255, 0.9);
    border-bottom: 2px solid rgba(148, 163, 184, 0.25);
  }

  [data-theme="dark"] .header {
    background: linear-gradient(135deg, 
      rgba(3, 7, 18, 0.99) 0%, 
      rgba(15, 23, 42, 0.97) 30%, 
      rgba(30, 41, 59, 0.95) 70%, 
      rgba(51, 65, 85, 0.93) 100%
    );
    backdrop-filter: blur(32px) saturate(200%);
    -webkit-backdrop-filter: blur(32px) saturate(200%);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.5), 
      0 8px 32px rgba(0, 0, 0, 0.8),
      0 0 0 1px rgba(96, 165, 250, 0.2),
      inset 0 1px 0 rgba(255, 255, 255, 0.12);
    border-bottom: 2px solid rgba(96, 165, 250, 0.4);
  }

  .nav {
    padding: 0 var(--space-md);
  }

  .nav-container {
    min-height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  /* Mobile Header Layout: Brand | Theme Toggle + Hamburger */
  .nav-brand {
    flex: 1;
  }

  .brand-title {
    font-size: var(--font-size-lg);
    font-weight: 800;
  }

  .brand-subtitle {
    font-size: var(--font-size-xs);
  }

  /* Mobile Header Right Side - Theme Toggle + Hamburger */
  .mobile-header-controls {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
  }

  /* Move theme toggle out of nav menu to header */
  .header-theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, 
      rgba(255, 255, 255, 0.9) 0%, 
      rgba(248, 250, 252, 0.8) 100%
    );
    border: 2px solid rgba(148, 163, 184, 0.3);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.06),
      0 0 0 1px rgba(255, 255, 255, 0.8),
      inset 0 1px 0 rgba(255, 255, 255, 0.9);
    /* Better mobile experience */
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
  }

  .header-theme-toggle::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
      transparent, 
      rgba(59, 130, 246, 0.15), 
      transparent
    );
    transition: left 0.6s ease;
  }

  .header-theme-toggle:hover::before {
    left: 100%;
  }

  .header-theme-toggle:hover {
    background: linear-gradient(135deg, 
      rgba(59, 130, 246, 0.12) 0%, 
      rgba(37, 99, 235, 0.08) 100%
    );
    border-color: rgba(59, 130, 246, 0.4);
    box-shadow: 
      0 4px 16px rgba(59, 130, 246, 0.15),
      0 0 0 1px rgba(255, 255, 255, 0.9),
      inset 0 1px 0 rgba(255, 255, 255, 0.95);
    transform: translateY(-1px);
  }

  /* Dark Mode Header Theme Toggle */
  [data-theme="dark"] .header-theme-toggle {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.25) 0%, 
      rgba(59, 130, 246, 0.2) 100%
    );
    border: 2px solid rgba(96, 165, 250, 0.5);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.4),
      0 0 0 1px rgba(255, 255, 255, 0.15),
      inset 0 1px 0 rgba(255, 255, 255, 0.2);
  }

  [data-theme="dark"] .header-theme-toggle::before {
    background: linear-gradient(90deg, 
      transparent, 
      rgba(96, 165, 250, 0.3), 
      transparent
    );
  }

  [data-theme="dark"] .header-theme-toggle:hover {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.35) 0%, 
      rgba(59, 130, 246, 0.3) 100%
    );
    border-color: rgba(96, 165, 250, 0.7);
    box-shadow: 
      0 4px 16px rgba(96, 165, 250, 0.25),
      0 0 16px rgba(96, 165, 250, 0.2),
      0 0 0 1px rgba(255, 255, 255, 0.2),
      inset 0 1px 0 rgba(255, 255, 255, 0.25);
    transform: translateY(-1px);
  }

  /* Header Theme Icon Container */
  .header-theme-icon {
    font-size: var(--font-size-lg);
    transition: all var(--transition-normal);
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.1));
  }

  [data-theme="dark"] .header-theme-icon {
    filter: drop-shadow(0 0 4px rgba(96, 165, 250, 0.4));
  }

  .header-theme-toggle:hover .header-theme-icon {
    transform: scale(1.1) rotate(15deg);
  }

  /* Header Theme Icon Switching Logic */
  /* Default state (light mode) */
  .header-theme-icon.moon {
    display: block;
  }

  .header-theme-icon.sun {
    display: none;
  }

  /* Light mode explicit */
  [data-theme="light"] .header-theme-icon.moon {
    display: block;
  }

  [data-theme="light"] .header-theme-icon.sun {
    display: none;
  }

  /* Dark mode */
  [data-theme="dark"] .header-theme-icon.moon {
    display: none;
  }

  [data-theme="dark"] .header-theme-icon.sun {
    display: block;
  }

  /* Hide theme toggle from mobile nav menu since it's now in header */
  .nav-menu .theme-toggle {
    display: none;
  }

  .nav-toggle {
    background: rgba(59, 130, 246, 0.1);
    border: 1px solid rgba(59, 130, 246, 0.2);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
  }

  .nav-toggle:hover, .nav-toggle:focus {
    background: rgba(59, 130, 246, 0.15);
    border-color: rgba(59, 130, 246, 0.3);
    box-shadow: var(--shadow-md);
  }

  [data-theme="dark"] .nav-toggle {
    background: rgba(96, 165, 250, 0.15);
    border-color: rgba(96, 165, 250, 0.3);
  }

  [data-theme="dark"] .nav-toggle:hover, 
  [data-theme="dark"] .nav-toggle:focus {
    background: rgba(96, 165, 250, 0.2);
    border-color: rgba(96, 165, 250, 0.4);
  }

  .nav-menu {
    background: linear-gradient(135deg, 
      rgba(255, 255, 255, 0.95) 0%, 
      rgba(248, 250, 252, 0.92) 50%, 
      rgba(241, 245, 249, 0.90) 100%
    );
    backdrop-filter: blur(32px) saturate(200%);
    -webkit-backdrop-filter: blur(32px) saturate(200%);
    border: 2px solid rgba(59, 130, 246, 0.2);
    border-radius: 20px;
    box-shadow: 
      0 8px 32px rgba(0, 0, 0, 0.12), 
      0 20px 60px rgba(0, 0, 0, 0.08),
      inset 0 1px 0 rgba(255, 255, 255, 0.8);
  }

  [data-theme="dark"] .nav-menu {
    background: linear-gradient(135deg, 
      rgba(15, 23, 42, 0.95) 0%, 
      rgba(30, 41, 59, 0.92) 50%, 
      rgba(51, 65, 85, 0.90) 100%
    );
    border: 2px solid rgba(96, 165, 250, 0.3);
    box-shadow: 
      0 8px 32px rgba(0, 0, 0, 0.4), 
      0 20px 60px rgba(0, 0, 0, 0.6),
      inset 0 1px 0 rgba(255, 255, 255, 0.1);
  }

  .nav-link {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-lg);
    margin: var(--space-xs) 0;
    border-radius: var(--radius-xl);
    transition: all var(--transition-normal);
    text-decoration: none;
    position: relative;
    overflow: hidden;
    font-weight: 500;
    
    /* Modern glassmorphism effect */
    background: linear-gradient(135deg, 
      rgba(255, 255, 255, 0.6) 0%, 
      rgba(248, 250, 252, 0.4) 100%
    );
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 2px solid rgba(148, 163, 184, 0.2);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.04),
      inset 0 1px 0 rgba(255, 255, 255, 0.5);
  }

  /* Dark mode nav links */
  [data-theme="dark"] .nav-link {
    background: linear-gradient(135deg, 
      rgba(30, 41, 59, 0.6) 0%, 
      rgba(51, 65, 85, 0.4) 100%
    );
    border-color: rgba(96, 165, 250, 0.2);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.3),
      inset 0 1px 0 rgba(255, 255, 255, 0.1);
    color: var(--color-text);
  }

  /* Hover sweep effect */
  .nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
      transparent, 
      rgba(59, 130, 246, 0.15), 
      transparent
    );
    transition: left 0.5s ease;
  }

  .nav-link:hover::before {
    left: 100%;
  }

  .nav-link:hover, .nav-link:focus {
    background: linear-gradient(135deg, 
      rgba(59, 130, 246, 0.15) 0%, 
      rgba(37, 99, 235, 0.1) 100%
    );
    border-color: rgba(59, 130, 246, 0.4);
    box-shadow: 
      0 4px 16px rgba(59, 130, 246, 0.15),
      0 0 0 1px rgba(255, 255, 255, 0.9),
      inset 0 1px 0 rgba(255, 255, 255, 0.8);
    transform: translateX(8px) scale(1.02);
    color: var(--color-primary-dark);
  }

  [data-theme="dark"] .nav-link:hover,
  [data-theme="dark"] .nav-link:focus {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.25) 0%, 
      rgba(59, 130, 246, 0.2) 100%
    );
    border-color: rgba(96, 165, 250, 0.5);
    box-shadow: 
      0 4px 16px rgba(96, 165, 250, 0.25),
      0 0 0 1px rgba(255, 255, 255, 0.15),
      inset 0 1px 0 rgba(255, 255, 255, 0.2);
    color: var(--color-primary);
  }

  .nav-link.active {
    background: linear-gradient(135deg, 
      rgba(59, 130, 246, 0.9) 0%, 
      rgba(37, 99, 235, 0.95) 100%
    );
    color: white;
    box-shadow: 
      0 4px 20px rgba(59, 130, 246, 0.4),
      0 0 0 1px rgba(255, 255, 255, 0.2),
      inset 0 1px 0 rgba(255, 255, 255, 0.3);
    border-color: transparent;
    font-weight: 600;
  }

  [data-theme="dark"] .nav-link.active {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.8) 0%, 
      rgba(59, 130, 246, 0.85) 100%
    );
    box-shadow: 
      0 4px 20px rgba(96, 165, 250, 0.5),
      0 0 24px rgba(96, 165, 250, 0.3),
      inset 0 1px 0 rgba(255, 255, 255, 0.3);
  }

  /* Active indicator */
  .nav-link.active::after {
    content: '';
    position: absolute;
    top: 50%;
    right: var(--space-md);
    transform: translateY(-50%);
    width: 4px;
    height: 60%;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 2px;
    box-shadow: 0 0 8px rgba(255, 255, 255, 0.3);
  }

  /* Nav link icons */
  .nav-link i {
    font-size: var(--font-size-lg);
    width: 24px;
    text-align: center;
    transition: all var(--transition-normal);
  }

  .nav-link:hover i {
    transform: scale(1.1) rotate(5deg);
  }

  .nav-link.active i {
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
  }

  .theme-toggle {
    border-radius: var(--radius-xl);
    background: linear-gradient(135deg, 
      rgba(255, 255, 255, 0.9) 0%, 
      rgba(248, 250, 252, 0.8) 50%, 
      rgba(241, 245, 249, 0.7) 100%
    );
    border: 2px solid rgba(148, 163, 184, 0.3);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.06),
      0 0 0 1px rgba(255, 255, 255, 0.8),
      inset 0 1px 0 rgba(255, 255, 255, 0.9);
    position: relative;
    overflow: hidden;
    min-height: 48px;
    transition: all var(--transition-normal);
  }

  .theme-toggle::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
      transparent, 
      rgba(59, 130, 246, 0.15), 
      transparent
    );
    transition: left 0.6s ease;
  }

  .theme-toggle:hover::before {
    left: 100%;
  }

  .theme-toggle:hover, .theme-toggle:focus {
    background: linear-gradient(135deg, 
      rgba(59, 130, 246, 0.12) 0%, 
      rgba(37, 99, 235, 0.08) 50%, 
      rgba(29, 78, 216, 0.06) 100%
    );
    border-color: rgba(59, 130, 246, 0.4);
    box-shadow: 
      0 4px 16px rgba(59, 130, 246, 0.15),
      0 0 0 1px rgba(255, 255, 255, 0.9),
      inset 0 1px 0 rgba(255, 255, 255, 0.95);
    transform: translateX(4px) scale(1.02);
  }

  /* Enhanced Dark Mode Mobile Theme Toggle */
  [data-theme="dark"] .theme-toggle {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.25) 0%, 
      rgba(59, 130, 246, 0.2) 50%, 
      rgba(37, 99, 235, 0.15) 100%
    );
    border: 2px solid rgba(96, 165, 250, 0.5);
    box-shadow: 
      0 2px 8px rgba(0, 0, 0, 0.4),
      0 0 0 1px rgba(255, 255, 255, 0.15),
      inset 0 1px 0 rgba(255, 255, 255, 0.2);
    color: var(--color-text);
  }

  [data-theme="dark"] .theme-toggle::before {
    background: linear-gradient(90deg, 
      transparent, 
      rgba(96, 165, 250, 0.3), 
      transparent
    );
  }

  [data-theme="dark"] .theme-toggle:hover, 
  [data-theme="dark"] .theme-toggle:focus {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.35) 0%, 
      rgba(59, 130, 246, 0.3) 50%, 
      rgba(37, 99, 235, 0.25) 100%
    );
    border-color: rgba(96, 165, 250, 0.7);
    box-shadow: 
      0 4px 16px rgba(96, 165, 250, 0.25),
      0 0 16px rgba(96, 165, 250, 0.2),
      0 0 0 1px rgba(255, 255, 255, 0.2),
      inset 0 1px 0 rgba(255, 255, 255, 0.25);
    color: var(--color-primary);
    transform: translateX(4px) scale(1.02);
  }

  /* Enhanced Mobile Theme Icons */
  .theme-icon-container {
    position: relative;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: linear-gradient(135deg, 
      rgba(59, 130, 246, 0.1) 0%, 
      rgba(37, 99, 235, 0.05) 100%
    );
    transition: all var(--transition-normal);
  }

  [data-theme="dark"] .theme-icon-container {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.2) 0%, 
      rgba(59, 130, 246, 0.15) 100%
    );
    box-shadow: 
      0 0 8px rgba(96, 165, 250, 0.3),
      inset 0 1px 0 rgba(255, 255, 255, 0.1);
  }

  .theme-toggle:hover .theme-icon-container {
    background: linear-gradient(135deg, 
      rgba(59, 130, 246, 0.2) 0%, 
      rgba(37, 99, 235, 0.15) 100%
    );
    transform: rotate(5deg);
    /* Removed scale and box-shadow to prevent overflow */
  }

  [data-theme="dark"] .theme-toggle:hover .theme-icon-container {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.35) 0%, 
      rgba(59, 130, 246, 0.25) 100%
    );
    transform: rotate(-5deg);
    /* Removed scale and external box-shadow to prevent overflow */
  }

  .theme-icon {
    font-size: var(--font-size-lg);
    transition: all var(--transition-normal);
    position: absolute;
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.1));
  }

  [data-theme="dark"] .theme-icon {
    filter: drop-shadow(0 0 4px rgba(96, 165, 250, 0.4));
  }

  .theme-toggle-text {
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    position: relative;
    z-index: 1;
  }
}

/* Desktop Navigation */
@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
  
  /* Hide mobile header controls on desktop */
  .mobile-header-controls {
    display: none;
  }
  
  /* Show regular nav menu theme toggle on desktop */
  .nav-menu .theme-toggle {
    display: flex !important;
  }
  
  .nav-menu {
    display: flex;
    position: static;
    background: none;
    border: none;
    box-shadow: none;
    padding: var(--space-xs) var(--space-md); /* Add padding to contain hover effects */
    align-items: center;
    gap: var(--space-sm);
    animation: none;
  }
  
  .nav-link {
    padding: var(--space-sm) var(--space-lg);
    margin-bottom: 0;
    border-radius: 12px;
    font-size: var(--font-size-sm);
    transition: all var(--transition-fast);
    white-space: nowrap;
  }
  
  .nav-link:hover, .nav-link:focus {
    background-color: var(--color-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
  }
  
  .nav-link.active {
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
    box-shadow: var(--shadow-md);
  }
  
  .theme-toggle {
    width: auto;
    padding: var(--space-sm) var(--space-md);
    border-radius: 12px;
    margin-bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 48px;
    gap: var(--space-xs);
    overflow: hidden; /* Contain hover effects within button */
    position: relative; /* Ensure proper stacking context */
  }
  
  .theme-toggle:hover, .theme-toggle:focus {
    background-color: var(--color-hover);
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.1);
    filter: brightness(1.05);
  }
  
  .theme-toggle:active {
    background-color: var(--color-active);
    /* No transform or shadow effects to prevent overflow */
  }
  
  .theme-toggle-text {
    display: none; /* Hide text on desktop for cleaner look */
  }
  
  /* Dark Mode Desktop Theme Toggle */
  [data-theme="dark"] .theme-toggle {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.2) 0%, 
      rgba(59, 130, 246, 0.15) 100%
    );
    border: 1px solid rgba(96, 165, 250, 0.4);
    color: var(--color-text);
    box-shadow: 
      var(--shadow-sm),
      0 0 0 1px rgba(255, 255, 255, 0.08),
      inset 0 1px 0 rgba(255, 255, 255, 0.12);
  }
  
  [data-theme="dark"] .theme-toggle:hover, 
  [data-theme="dark"] .theme-toggle:focus {
    background: linear-gradient(135deg, 
      rgba(96, 165, 250, 0.3) 0%, 
      rgba(59, 130, 246, 0.25) 100%
    );
    border-color: rgba(96, 165, 250, 0.6);
    color: var(--color-primary);
    filter: brightness(1.1);
  }
}

/* ==========================================================================
   Main Content
   ========================================================================== */

.main {
  /* No margin-top needed since header is sticky (not fixed) */
  min-height: calc(100vh - 64px); /* Account for header height */
  padding-bottom: var(--space-3xl); /* Add bottom padding since no footer */
}

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

.hero {
  padding: var(--space-lg) 0; /* Reduced from 2xl to lg for mobile */
  background: linear-gradient(135deg, 
    rgba(59, 130, 246, 0.02) 0%, 
    rgba(139, 92, 246, 0.02) 50%, 
    rgba(6, 182, 212, 0.02) 100%
  );
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: 
    radial-gradient(circle at 25% 25%, rgba(59, 130, 246, 0.04) 0%, transparent 50%),
    radial-gradient(circle at 75% 75%, rgba(139, 92, 246, 0.04) 0%, transparent 50%);
  pointer-events: none;
}

.hero-title {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.hero-description {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

@media (min-width: 768px) {
  .hero {
    padding: var(--space-2xl) 0; /* Reduced from 3xl to 2xl for desktop */
  }
  
  .hero-title {
    font-size: var(--font-size-4xl);
  }
  
  .hero-description {
    font-size: var(--font-size-xl);
  }
}

/* ==========================================================================
   Cards & Grids
   ========================================================================== */

.tool-grid {
  display: grid;
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

@media (min-width: 768px) {
  .tool-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
  }
}

.tool-card {
  background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.tool-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transition: left 0.6s ease;
}

.tool-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl), var(--shadow-glow);
  border-color: var(--color-primary);
}

.tool-card:hover::before {
  left: 100%;
}

.tool-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

.tool-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-sm) var(--space-lg);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  border-radius: var(--radius-lg);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  min-height: 44px; /* Touch target minimum */
  user-select: none;
  /* Better mobile experience */
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

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

.btn:active {
  transform: translateY(1px) scale(0.98);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-text-inverse);
  border-color: var(--color-primary-dark);
  box-shadow: var(--shadow-md), inset 0 1px 0 rgba(255, 255, 255, 0.2);
  font-weight: var(--font-weight-semibold);
}

.btn-primary:hover, .btn-primary:focus {
  background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-primary) 100%);
  border-color: var(--color-primary);
  color: var(--color-text-inverse);
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-secondary {
  background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
  color: var(--color-text);
  border-color: var(--color-border-secondary);
  box-shadow: var(--shadow-sm), inset 0 1px 0 rgba(255, 255, 255, 0.8);
  font-weight: var(--font-weight-medium);
}

.btn-secondary:hover, .btn-secondary:focus {
  background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg-tertiary) 100%);
  color: var(--color-primary);
  text-decoration: none;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

/* ==========================================================================
   Features Section
   ========================================================================== */

.features {
  padding: var(--space-3xl) 0;
}

.section-title {
  text-align: center;
  margin-bottom: var(--space-2xl);
  color: var(--color-text);
}

.feature-grid {
  display: grid;
  gap: var(--space-xl);
}

@media (min-width: 768px) {
  .feature-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-item {
  text-align: center;
  padding: var(--space-lg);
}

.feature-item h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-sm);
}

.feature-item p {
  color: var(--color-text-secondary);
  margin: 0;
}


/* ==========================================================================
   Utility Classes
   ========================================================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-grid { display: grid; }

@media (min-width: 768px) {
  .d-md-none { display: none; }
  .d-md-block { display: block; }
  .d-md-flex { display: flex; }
  .d-md-grid { display: grid; }
}

/* ==========================================================================
   Animations
   ========================================================================== */

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

/* ==========================================================================
   Print Styles
   ========================================================================== */

@media print {
  .header, .nav-toggle, .theme-toggle {
    display: none;
  }
  
  .main {
    margin-top: 0;
  }
  
  * {
    background: white !important;
    color: black !important;
    box-shadow: none !important;
  }
}

/* ==========================================================================
   Warning Notice & Modal Styles
   ========================================================================== */

/* Simple Notice Styling */
.simple-notice {
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
  border: 2px solid #f59e0b;
  border-left: 6px solid #d97706;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.3);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

/* Dark Mode Simple Notice */
[data-theme="dark"] .simple-notice {
  background: linear-gradient(135deg, rgba(254, 243, 199, 0.2) 0%, rgba(253, 230, 138, 0.15) 100%);
  border: 2px solid #fbbf24;
  border-left: 6px solid #f59e0b;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.3);
}


.warning-header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-xs) var(--space-sm);
}

.warning-icon {
  font-size: 1.125rem;
  filter: drop-shadow(0 2px 4px rgba(217, 119, 6, 0.3));
}

.warning-content {
  /* Content no longer needs to flex since no click indicator */
}


.warning-description {
  font-size: 0.75rem;
  color: #b45309;
  margin: 0;
  font-weight: 500;
  text-align: center;
  line-height: 1.2;
}


/* Enhanced Warning Notice Content for Dark Mode */
[data-theme="dark"] .warning-icon {
  filter: drop-shadow(0 2px 8px rgba(245, 158, 11, 0.6));
}

[data-theme="dark"] .warning-description {
  color: #fef3c7;
  font-weight: 500;
}


}



/* ==========================================================================
   PWA Specific Styles
   ========================================================================== */

/* PWA standalone mode detection and fixes */
.pwa-mode .header {
  position: fixed \!important;
  top: 0 \!important;
  left: 0 \!important;
  right: 0 \!important;
  z-index: 9999 \!important;
  border-bottom: 2px solid var(--color-border) \!important;
}

.pwa-mode .main {
  margin-top: 64px \!important;
  min-height: calc(100vh - 64px) \!important;
}

/* Ensure PWA header controls work properly */
.pwa-mode .nav-toggle {
  z-index: 10000 \!important;
  position: relative \!important;
}

.pwa-mode .header-theme-toggle {
  z-index: 10000 \!important;
  position: relative \!important;
}

.pwa-mode .nav-menu {
  z-index: 10001 \!important;
  position: fixed \!important;
  top: 72px \!important;
}

/* PWA Mobile fixes */
@media (max-width: 767px) {
  .pwa-mode .mobile-header-controls {
    display: flex \!important;
    align-items: center \!important;
    gap: var(--space-sm) \!important;
  }
  
  .pwa-mode .header-theme-toggle {
    display: flex \!important;
    width: 48px \!important;
    height: 48px \!important;
  }
  
  .pwa-mode .nav-toggle {
    display: flex \!important;
    width: 48px \!important;
    height: 48px \!important;
  }
}

/* Standalone mode specific styles */
@media (display-mode: standalone) {
  .header {
    position: fixed \!important;
    top: 0 \!important;
    left: 0 \!important;
    right: 0 \!important;
    z-index: 9999 \!important;
  }
  
  .main {
    margin-top: 64px \!important;
  }
  
  .nav-menu {
    z-index: 10001 \!important;
    position: fixed \!important;
    top: 72px \!important;
  }
}

/* iOS Safari PWA specific fixes */
@supports (-webkit-touch-callout: none) {
  .pwa-mode .header,
  @media (display-mode: standalone) {
    .header {
      padding-top: env(safe-area-inset-top) \!important;
      height: calc(64px + env(safe-area-inset-top)) \!important;
    }
    
    .main {
      margin-top: calc(64px + env(safe-area-inset-top)) \!important;
    }
  }
}