/* ErgoHaus DE - Focus Grid Aesthetic */

/* ===== CSS Variables (Design Tokens) ===== */
:root {
  /* Color Palette */
  --color-graphite: #1A2230;
  --color-navy: #0B1220;
  --color-signal-blue: #3AA7FF;
  --color-mint: #20C6B7;
  --color-gray: #A7B0BD;
  
  /* Semantic Colors */
  --color-bg-primary: var(--color-navy);
  --color-bg-secondary: var(--color-graphite);
  --color-text-primary: #FFFFFF;
  --color-text-secondary: var(--color-gray);
  --color-accent: var(--color-signal-blue);
  --color-accent-mint: var(--color-mint);
  --color-border: rgba(255, 255, 255, 0.1);
  --color-card-bg: rgba(26, 34, 48, 0.8);
  --color-hover: rgba(58, 167, 255, 0.1);
  
  /* Typography */
  --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2.25rem;
  --font-size-4xl: 3.1rem;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Layout */
  --max-width: 1200px;
  --gutter: 1.5rem;
  --border-radius: 16px;
  --card-shadow: 0 12px 28px rgba(0, 0, 0, 0.24);
  
  /* Transitions */
  --transition-fast: 160ms ease;
  --transition-normal: 220ms ease;
  --transition-slow: 320ms ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  background: var(--color-bg-primary);
  color: var(--color-text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

/* ===== Focus Grid Background Animation ===== */
.focus-grid-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-graphite) 100%);
  overflow: hidden;
}

.focus-grid-bg::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background-image: 
    linear-gradient(rgba(58, 167, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(58, 167, 255, 0.03) 1px, transparent 1px);
  background-size: 50px 50px;
  animation: gridMove 20s linear infinite;
}

@keyframes gridMove {
  0% { transform: translate(0, 0); }
  100% { transform: translate(50px, 50px); }
}

.focus-grid-bg::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(
    circle at 50% 50%, 
    rgba(32, 198, 183, 0.05) 0%, 
    transparent 50%
  );
  animation: pulse 8s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 0.8; }
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: var(--font-size-4xl);
  font-weight: 700;
}

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-base);
}

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

/* ===== Layout Components ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-sm {
  padding: var(--spacing-2xl) 0;
}

/* ===== Grid System ===== */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-6 { grid-template-columns: repeat(6, 1fr); }

/* ===== Header ===== */
.header {
  position: sticky;
  top: 0;
  background: rgba(11, 18, 32, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  transition: all var(--transition-normal);
}

.header.scrolled {
  background: rgba(11, 18, 32, 0.98);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

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

.logo {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.logo-accent {
  color: var(--color-accent);
}

/* ===== Navigation ===== */
.nav {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
}

.nav-list {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
  margin: 0;
}

.nav-link {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: 8px;
  transition: all var(--transition-fast);
  position: relative;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-text-primary);
  background: var(--color-hover);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: all var(--transition-fast);
  transform: translateX(-50%);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 80%;
}

/* ===== Mobile Menu ===== */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-primary);
  cursor: pointer;
  padding: var(--spacing-sm);
}

.mobile-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--color-bg-primary);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-lg);
}

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

.mobile-nav-list {
  list-style: none;
  flex-direction: column;
  gap: var(--spacing-md);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm) var(--spacing-lg);
  border: none;
  border-radius: 8px;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: var(--font-size-base);
}

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

.btn-primary:hover {
  background: #2a8de6;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(58, 167, 255, 0.3);
}

.btn-secondary {
  background: transparent;
  color: var(--color-accent);
  border: 2px solid var(--color-accent);
}

.btn-secondary:hover {
  background: var(--color-accent);
  color: white;
}

.btn-link {
  background: transparent;
  color: var(--color-accent);
  padding: var(--spacing-sm) 0;
}

.btn-link:hover {
  color: var(--color-accent-mint);
}

/* ===== Cards ===== */
.card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--spacing-xl);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-mint));
  transform: scaleX(0);
  transition: transform var(--transition-normal);
}

.card:hover::before {
  transform: scaleX(1);
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--card-shadow);
  border-color: rgba(58, 167, 255, 0.3);
}

.card-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 12px;
  margin-bottom: var(--spacing-lg);
}

.card-title {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-sm);
}

.card-description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

/* ===== Badges & Chips ===== */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.badge-beginner {
  background: rgba(32, 198, 183, 0.2);
  color: var(--color-accent-mint);
}

.badge-advanced {
  background: rgba(58, 167, 255, 0.2);
  color: var(--color-accent);
}

.badge-quick-fix {
  background: rgba(167, 176, 189, 0.2);
  color: var(--color-gray);
}

/* ===== Hero Section ===== */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 1;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4rem);
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--color-text-primary) 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

.hero-cta {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Stats Section ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-3xl);
}

.stat-card {
  text-align: center;
  padding: var(--spacing-xl);
}

.stat-number {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: var(--spacing-sm);
}

.stat-label {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* ===== Article Grid ===== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-3xl);
}

/* ===== Filter Chips ===== */
.filter-chips {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
  flex-wrap: wrap;
}

.filter-chip {
  padding: var(--spacing-sm) var(--spacing-lg);
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  border-radius: 25px;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: var(--font-size-sm);
}

.filter-chip:hover,
.filter-chip.active {
  background: var(--color-accent);
  color: white;
  border-color: var(--color-accent);
}

/* ===== Newsletter ===== */
.newsletter {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--spacing-3xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.newsletter::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-mint));
}

.newsletter-form {
  display: flex;
  gap: var(--spacing-md);
  max-width: 500px;
  margin: 0 auto;
  margin-top: var(--spacing-lg);
}

.newsletter-input {
  flex: 1;
  padding: var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  background: var(--color-bg-secondary);
  color: var(--color-text-primary);
  font-size: var(--font-size-base);
}

.newsletter-input::placeholder {
  color: var(--color-text-secondary);
}

/* ===== Footer ===== */
.footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
  margin-top: var(--spacing-3xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-xl);
}

.footer-section h5 {
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-lg);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--spacing-sm);
}

.footer-links a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-lg);
  text-align: center;
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

/* ===== Icons ===== */
.icon {
  width: 24px;
  height: 24px;
  display: inline-block;
  vertical-align: middle;
}

.icon-lg {
  width: 48px;
  height: 48px;
}

/* ===== Scroll Animations ===== */
.scroll-reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease;
}

.scroll-reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Back to Top Button ===== */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background: var(--color-accent);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  z-index: 100;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: #2a8de6;
  transform: translateY(-3px);
}

/* ===== Utilities ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

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

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --gutter: 1rem;
    --spacing-3xl: 2.5rem;
  }
  
  .nav-list {
    display: none;
  }
  
  .mobile-menu-toggle {
    display: block;
  }
  
  .grid-2,
  .grid-3,
  .grid-4,
  .grid-6 {
    grid-template-columns: 1fr;
  }
  
  .hero-cta {
    flex-direction: column;
    align-items: center;
  }
  
  .newsletter-form {
    flex-direction: column;
  }
  
  .filter-chips {
    justify-content: center;
  }
  
  .article-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .hero {
    min-height: 70vh;
  }
  
  .card {
    padding: var(--spacing-lg);
  }
}

/* ===== Accessibility ===== */
@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;
  }
  
  .focus-grid-bg::before,
  .focus-grid-bg::after {
    animation: none;
  }
}

/* Focus styles for keyboard navigation */
*:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus,
a:focus,
input:focus,
textarea:focus,
select:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}