/* =============================================================================
   USEFULWRITER LLC - PREMIUM DESIGN SYSTEM
   Inspired by Swiss minimalism and premium design principles
   ========================================================================== */

/* CSS Custom Properties - Design System */
:root {
  /* Colors - Monochromatic with subtle accents */
  --color-primary: #1a1a1a;
  --color-secondary: #666666;
  --color-tertiary: #999999;
  --color-accent: #2563eb;
  --color-background: #ffffff;
  --color-surface: #f8fafc;
  --color-surface-elevated: #ffffff;
  --color-border: #e2e8f0;
  --color-text-primary: #0f172a;
  --color-text-secondary: #475569;
  --color-text-tertiary: #64748b;
  
  /* Dark theme colors */
  --color-dark-primary: #ffffff;
  --color-dark-secondary: #cbd5e1;
  --color-dark-tertiary: #94a3b8;
  --color-dark-accent: #3b82f6;
  --color-dark-background: #0f172a;
  --color-dark-surface: #1e293b;
  --color-dark-surface-elevated: #334155;
  --color-dark-border: #475569;
  --color-dark-text-primary: #f8fafc;
  --color-dark-text-secondary: #cbd5e1;
  --color-dark-text-tertiary: #94a3b8;
  
  /* Spacing Scale - Perfect for premium layouts */
  --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 */
  --space-4xl: 6rem;      /* 96px */
  --space-5xl: 8rem;      /* 128px */
  
  /* Typography Scale - Harmonious ratios */
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 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-size-5xl: 3rem;      /* 48px */
  --font-size-6xl: 3.75rem;   /* 60px */
  
  /* Font Weights */
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --line-height-loose: 2;
  
  /* Border Radius - Subtle and refined */
  --radius-sm: 0.125rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-full: 50%;
  
  /* Shadows - Elegant depth */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --transition-slow: 0.5s ease;
  
  /* Layout */
  --max-width-prose: 65ch;
  --max-width-container: 75rem; /* 1200px */
}

/* Dark Theme */
[data-theme="dark"] {
  --color-primary: var(--color-dark-primary);
  --color-secondary: var(--color-dark-secondary);
  --color-tertiary: var(--color-dark-tertiary);
  --color-accent: var(--color-dark-accent);
  --color-background: var(--color-dark-background);
  --color-surface: var(--color-dark-surface);
  --color-surface-elevated: var(--color-dark-surface-elevated);
  --color-border: var(--color-dark-border);
  --color-text-primary: var(--color-dark-text-primary);
  --color-text-secondary: var(--color-dark-text-secondary);
  --color-text-tertiary: var(--color-dark-text-tertiary);
}

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

html {
  font-size: 100%;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Theme Toggle */
.theme-toggle-container {
  position: fixed;
  top: var(--space-lg);
  right: var(--space-lg);
  z-index: 1000;
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-surface-elevated);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-md);
}

.theme-toggle:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
  transform: scale(1.05);
}

.theme-icon {
  transition: all var(--transition-normal);
}

.theme-toggle .moon-icon {
  display: none;
}

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

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  letter-spacing: -0.025em;
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-xl);
}

h2 {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-lg);
}

h3 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-md);
}

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

.lead {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
}

/* Layout */
.container {
  max-width: var(--max-width-container);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Sections */
section {
  padding: var(--space-5xl) 0;
}

/* Welcome Section */
.welcome-section {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: linear-gradient(
    180deg,
    var(--color-background) 0%,
    var(--color-surface) 100%
  );
}

.welcome-content {
  max-width: 50rem;
}

.logo-image {
  width: 120px;
  height: 120px;
  border-radius: var(--radius-full);
  margin: 0 auto var(--space-3xl);
  display: block;
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-normal);
}

.logo-image:hover {
  transform: scale(1.05);
}

/* CTA Buttons */
.cta-button {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  text-decoration: none;
  padding: var(--space-lg) var(--space-2xl);
  border-radius: var(--radius-xl);
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  color: white;
  background: var(--color-accent);
  border: 1px solid var(--color-accent);
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.cta-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.1),
    transparent
  );
  transition: left var(--transition-slow);
}

.cta-button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

.cta-button:hover::before {
  left: 100%;
}

.cta-button.secondary {
  background: transparent;
  color: var(--color-text-primary);
  border-color: var(--color-border);
}

.cta-button.secondary:hover {
  background: var(--color-surface);
  border-color: var(--color-accent);
}

.cta-subtitle {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-normal);
  opacity: 0.8;
  margin-top: var(--space-xs);
}

/* About Section */
.about-section {
  background-color: var(--color-surface);
}

.about-content {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: var(--space-4xl);
  align-items: center;
}

.portrait-image {
  width: 100%;
  max-width: 300px;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-normal);
}

.portrait-image:hover {
  transform: scale(1.02);
}

.about-text h2 {
  color: var(--color-accent);
  margin-bottom: var(--space-lg);
}

.about-text p {
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
}

.about-text a {
  color: var(--color-accent);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-fast);
}

.about-text a:hover {
  text-decoration: underline;
}

/* Mission Section */
.mission-section {
  background-color: var(--color-background);
}

.mission-section h2 {
  text-align: center;
  color: var(--color-text-primary);
  margin-bottom: var(--space-4xl);
}

.mission-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: var(--space-2xl);
}

.mission-item {
  padding: var(--space-3xl);
  border-radius: var(--radius-2xl);
  background-color: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  text-align: center;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

.mission-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--color-accent);
}

.icon-container {
  margin-bottom: var(--space-xl);
}

.mission-icon {
  color: var(--color-accent);
  transition: transform var(--transition-normal);
}

.mission-item:hover .mission-icon {
  transform: scale(1.1);
}

.mission-item h3 {
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
}

.mission-item p {
  font-size: var(--font-size-base);
  line-height: var(--line-height-relaxed);
  max-width: none;
}

/* Contact Section */
.contact-section {
  background-color: var(--color-surface);
  text-align: center;
}

.contact-section h2 {
  color: var(--color-text-primary);
  margin-bottom: var(--space-lg);
}

.contact-content {
  max-width: 40rem;
  margin: 0 auto;
}

.contact-content > p {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-xl);
}

.contact-info {
  padding: var(--space-2xl);
  border-radius: var(--radius-2xl);
  background-color: var(--color-surface-elevated);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.contact-info p {
  margin-bottom: var(--space-sm);
}

.contact-info p:last-child {
  margin-bottom: 0;
}

.contact-info a {
  color: var(--color-accent);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: color var(--transition-fast);
}

.contact-info a:hover {
  text-decoration: underline;
}

/* Final CTA Section */
.final-cta-section {
  background: linear-gradient(
    135deg,
    var(--color-accent) 0%,
    #1d4ed8 100%
  );
  color: white;
  text-align: center;
}

.final-cta-content {
  max-width: 40rem;
  margin: 0 auto;
}

.final-cta-content h2 {
  color: white;
  margin-bottom: var(--space-lg);
}

.final-cta-content p {
  font-size: var(--font-size-lg);
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: var(--space-2xl);
  max-width: none;
}

/* Footer */
footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-xl) 0;
  text-align: center;
}

footer p {
  color: var(--color-text-tertiary);
  font-size: var(--font-size-sm);
  margin: 0;
}

/* Responsive Design */
@media (max-width: 1024px) {
  :root {
    --font-size-5xl: 2.5rem;
    --font-size-4xl: 2rem;
  }
  
  .container {
    padding: 0 var(--space-md);
  }
  
  .about-content {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
    text-align: center;
  }
  
  .mission-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

@media (max-width: 768px) {
  :root {
    --font-size-5xl: 2rem;
    --font-size-4xl: 1.75rem;
    --space-5xl: 4rem;
    --space-4xl: 3rem;
  }
  
  .theme-toggle-container {
    top: var(--space-md);
    right: var(--space-md);
  }
  
  section {
    padding: var(--space-4xl) 0;
  }
  
  .welcome-section {
    min-height: 80vh;
  }
  
  .logo-image {
    width: 100px;
    height: 100px;
    margin-bottom: var(--space-xl);
  }
  
  .cta-button {
    padding: var(--space-md) var(--space-lg);
    font-size: var(--font-size-base);
  }
  
  .mission-item {
    padding: var(--space-xl);
  }
  
  .contact-info {
    padding: var(--space-lg);
  }
}

@media (max-width: 480px) {
  :root {
    --font-size-5xl: 1.75rem;
    --font-size-4xl: 1.5rem;
    --font-size-2xl: 1.25rem;
  }
  
  .container {
    padding: 0 var(--space-sm);
  }
  
  .lead {
    font-size: var(--font-size-lg);
  }
  
  .about-content {
    gap: var(--space-lg);
  }
  
  .portrait-image {
    max-width: 200px;
  }
  
  .mission-item {
    padding: var(--space-lg);
  }
  
  .contact-info {
    padding: var(--space-md);
  }
}

/* Animation Classes */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.8s ease-out forwards;
}

/* Focus States for Accessibility */
.theme-toggle:focus,
.cta-button:focus,
a:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

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