/* CSS Custom Properties */
:root {
  /* Colors */
  --color-primary: #f0db4f;
  --color-primary-dark: #d4c23a;
  --color-secondary: #ff391b;
  --color-accent: #fbbe17;
  
  --color-bg-primary: #1a1a1a;
  --color-bg-secondary: #2d2d2d;
  --color-bg-tertiary: #3a3a3a;
  --color-bg-overlay: rgba(0, 0, 0, 0.8);
  
  --color-text-primary: #ffffff;
  --color-text-secondary: #bdbdbe;
  --color-text-muted: #8a8a8a;
  
  --color-border: #4a4a4a;
  --color-border-light: #6a6a6a;
  
  /* Typography */
  --font-family-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  
  --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: 1.875rem;
  --font-size-4xl: 2.25rem;
  
  --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;
  
  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  
  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;
  
  /* Shadows */
  --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: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Z-index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal: 1040;
  --z-popover: 1050;
  --z-tooltip: 1060;
}

/* Reset and base styles */
*,
*::before,
*::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-primary);
  color: var(--color-bg-primary);
  padding: 8px;
  text-decoration: none;
  border-radius: var(--radius-md);
  z-index: var(--z-tooltip);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 6px;
}

/* Header */
.header {
  text-align: center;
  padding: var(--space-16) var(--space-4) var(--space-12);
  max-width: 1200px;
  margin: 0 auto;
}

.header__title {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-4);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header__subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-normal);
}

/* Main content */
.main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4) var(--space-16);
}

/* Katas grid */
.katas {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-16);
}

/* Wider screens - show more columns */
@media (min-width: 1400px) {
  .katas {
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    max-width: 1400px;
    margin: 0 auto var(--space-16);
  }
}

@media (min-width: 1600px) {
  .katas {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    max-width: 1600px;
  }
}

/* Kata cards */
.kata-card {
  position: relative;
  background: var(--color-bg-secondary);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: all var(--transition-normal);
  border: 1px solid var(--color-border);
}

.kata-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--color-border-light);
}

.kata-card--coming-soon {
  opacity: 0.6;
  cursor: not-allowed;
}

.kata-card__link {
  display: block;
  text-decoration: none;
  color: inherit;
  height: 100%;
  min-height: 300px;
  position: relative;
}

.kata-card__link--disabled {
  pointer-events: none;
  cursor: not-allowed;
}

.kata-card__image-container {
  position: relative;
  height: 200px;
  overflow: hidden;
}

.kata-card__image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-normal);
}

.kata-card:hover .kata-card__image {
  transform: scale(1.05);
}

.kata-card__placeholder {
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-bg-tertiary) 0%, var(--color-bg-secondary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
}

.kata-card__placeholder-icon {
  font-size: var(--font-size-4xl);
  opacity: 0.5;
}

.kata-card__badge {
  position: absolute;
  top: var(--space-3);
  background: var(--color-primary);
  color: var(--color-bg-primary);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-full);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  box-shadow: var(--shadow-md);
  z-index: 2;
}

.kata-card__badge--mobile {
  background: #4CAF50;
  right: var(--space-3);
}

.kata-card__badge--desktop {
  background: #2196F3;
  right: var(--space-3);
}

/* Recommended badge positioning */
.kata-card__badge:not([class*="--mobile"]):not([class*="--desktop"]) {
  background: var(--color-primary);
  right: var(--space-3);
}

/* Multiple device badges - position them side by side */
.kata-card__badge--desktop + .kata-card__badge--mobile,
.kata-card__badge--mobile + .kata-card__badge--desktop {
  right: calc(var(--space-3) + 2.5rem);
}

/* When recommended badge is present with device badges */
.kata-card--recommended .kata-card__badge--mobile {
  right: calc(var(--space-3) + 2.5rem);
}

.kata-card--recommended .kata-card__badge--desktop {
  right: calc(var(--space-3) + 2.5rem);
}

/* When both mobile and desktop badges are present with recommended */
.kata-card--recommended .kata-card__badge--desktop + .kata-card__badge--mobile,
.kata-card--recommended .kata-card__badge--mobile + .kata-card__badge--desktop {
  right: calc(var(--space-3) + 5rem);
}

.kata-card__content {
  padding: var(--space-6);
  background: var(--color-bg-secondary);
}

.kata-card__title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-2);
  color: var(--color-text-primary);
}

.kata-card__description {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-relaxed);
}

/* Legend */
.legend {
  background: var(--color-bg-overlay);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin: var(--space-8) auto var(--space-12);
  max-width: 400px;
  border: 1px solid var(--color-border);
}

.legend__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-4);
  color: var(--color-text-primary);
}

.legend__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.legend__item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--font-size-sm);
}

.legend__icon {
  font-size: var(--font-size-lg);
}

.legend__item--recommended .legend__icon {
  color: var(--color-primary);
}

.legend__item--mobile .legend__icon {
  color: #4CAF50;
}

.legend__item--desktop .legend__icon {
  color: #2196F3;
}

.legend__item--wip .legend__icon {
  color: var(--color-secondary);
}

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

/* Footer */
.footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--space-8) var(--space-4);
  margin-top: var(--space-16);
}

.footer__content {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-6);
}

.footer__author {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.footer__avatar {
  border-radius: var(--radius-full);
  border: 2px solid var(--color-border);
  transition: border-color var(--transition-normal);
}

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

.footer__info {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

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

.footer__link:hover {
  color: var(--color-primary);
}

.footer__copyright {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.footer__github {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: var(--color-text-primary);
  transition: all var(--transition-normal);
}

.footer__github:hover {
  background: var(--color-bg-primary);
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.footer__github img {
  filter: invert(1);
  transition: filter var(--transition-fast);
}

.footer__github:hover img {
  filter: invert(1) sepia(1) saturate(5) hue-rotate(45deg);
}

.footer__github-text {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
}

/* Responsive design */
@media (max-width: 1024px) {
  .katas {
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--space-5);
  }
  
  .header {
    padding: var(--space-12) var(--space-4) var(--space-8);
  }
  
  .header__title {
    font-size: var(--font-size-3xl);
  }
}

@media (max-width: 768px) {
  .katas {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-4);
  }
  
  .kata-card__content {
    padding: var(--space-4);
  }
  
  .kata-card__title {
    font-size: var(--font-size-lg);
  }
  
  .header__title {
    font-size: var(--font-size-2xl);
  }
  
  .header__subtitle {
    font-size: var(--font-size-base);
  }
  
  .footer__content {
    flex-direction: column;
    text-align: center;
    gap: var(--space-4);
  }
  
  .footer__author {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 768px) {
  .katas {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }
  
  .kata-card__content {
    padding: var(--space-4);
  }
  
  .kata-card__title {
    font-size: var(--font-size-lg);
  }
  
  .header__title {
    font-size: var(--font-size-2xl);
  }
  
  .header__subtitle {
    font-size: var(--font-size-base);
  }
  
  .footer__content {
    flex-direction: column;
    text-align: center;
    gap: var(--space-4);
  }
  
  .footer__author {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .main {
    padding: 0 var(--space-3) var(--space-12);
  }
  
  .header {
    padding: var(--space-8) var(--space-3) var(--space-6);
  }
  
  .header__title {
    font-size: var(--font-size-xl);
  }
  
  .kata-card__link {
    min-height: 250px;
  }
  
  .kata-card__image-container {
    height: 150px;
  }
  
  .legend {
    margin: var(--space-6) var(--space-3) var(--space-8);
    padding: var(--space-4);
  }
  
  .footer {
    padding: var(--space-6) var(--space-3);
  }
}