/* ================================
   Keycap UI — Single Source of Truth
   Light by default, Dark optional
   Optimized for performance & accessibility
   ================================ */

/* Critical CSS inlined for faster rendering */

/* Theme tokens */
:root {
  --kc-bg: #f4f5f7;            /* page background (light gray) */
  --kc-surface: #ffffff;       /* keycap surface */
  --kc-surface-2: #f0f1f4;     /* secondary surface / nav capsule */
  --kc-text: #1f2329;          /* primary text */
  --kc-text-weak: #5f6672;     /* secondary text */

  --kc-primary: #ff774a;       /* CTA orange-red */
  --kc-primary-2: #ff5a2a;

  --kc-shadow-strong: 0 14px 28px rgba(23,28,33,.18), 0 10px 10px rgba(23,28,33,.10);
  --kc-shadow-soft:   0 8px 16px rgba(23,28,33,.14), 0 4px 8px rgba(23,28,33,.08);
  --kc-shadow-ring:   0 0 0 3px rgba(255,119,74,.22);
  --kc-bevel-light: inset 0 2px 0 rgba(255,255,255,.9);
  --kc-bevel-dark:  inset 0 -2px 0 rgba(0,0,0,.06);

  --kc-radius-xl: 18px;        /* keycap corner */
  --kc-radius-md: 14px;
  --kc-radius-pill: 9999px;

  /* layout */
  --container-max: 1200px;
  --container-pad: 1rem;

  color-scheme: light;
}

/* Auto dark mode; manual override via [data-theme="dark"] */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --kc-bg: #0f1115;
    --kc-surface: #171a23;
    --kc-surface-2: #131622;
    --kc-text: #e6e7ea;
    --kc-text-weak: #aeb3bd;

    --kc-shadow-strong: 0 16px 32px rgba(0,0,0,.45), 0 8px 12px rgba(0,0,0,.28);
    --kc-shadow-soft:   0 10px 22px rgba(0,0,0,.35), 0 6px 10px rgba(0,0,0,.22);
    --kc-shadow-ring:   0 0 0 3px rgba(255,119,74,.18);

    color-scheme: dark;
  }
}

/* Manual theme control */
:root[data-theme="light"] {
  --kc-bg: #f4f5f7;
  --kc-surface: #ffffff;
  --kc-surface-2: #f0f1f4;
  --kc-text: #1f2329;
  --kc-text-weak: #5f6672;

  --kc-shadow-strong: 0 14px 28px rgba(23,28,33,.18), 0 10px 10px rgba(23,28,33,.10);
  --kc-shadow-soft:   0 8px 16px rgba(23,28,33,.14), 0 4px 8px rgba(23,28,33,.08);
  --kc-shadow-ring:   0 0 0 3px rgba(255,119,74,.22);

  color-scheme: light;
}
:root[data-theme="dark"] {
  --kc-bg: #0f1115;
  --kc-surface: #171a23;
  --kc-surface-2: #131622;
  --kc-text: #e6e7ea;
  --kc-text-weak: #aeb3bd;

  --kc-shadow-strong: 0 16px 32px rgba(0,0,0,.45), 0 8px 12px rgba(0,0,0,.28);
  --kc-shadow-soft:   0 10px 22px rgba(0,0,0,.35), 0 6px 10px rgba(0,0,0,.22);
  --kc-shadow-ring:   0 0 0 3px rgba(255,119,74,.18);

  color-scheme: dark;
}

/* Base & Performance */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  margin: 0;
  padding: 0;
  background: var(--kc-bg);
  color: var(--kc-text);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

/* Header - Clean & Minimal */
header {
  background: transparent;
  padding: 2rem 1rem 1.5rem;
  text-align: center;
}

header h1 {
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--kc-text);
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 1px;
  position: relative;
  display: inline-block;
}

/* Add subtle glow effect to title */
header h1::after {
  content: "";
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--kc-primary), var(--kc-primary-2));
  border-radius: 2px;
  box-shadow: 0 2px 8px rgba(255, 119, 74, 0.3);
}

/* Nav — keycap pills with optimized spacing */
nav {
  background: transparent;
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: 0.5rem 0 1rem;
  display: flex;
  justify-content: center;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
nav .nav-wrap {
  max-width: var(--container-max);
  padding: 0 var(--container-pad);
  margin: 0 auto;
  width: 100%;
  display: flex;
  justify-content: center;
  text-align: center;
}
nav ul {
  list-style: none;
  padding: .5rem;
  margin: 0 auto;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: .35rem;
  width: max-content;
  background: var(--kc-surface-2);
  border: 1px solid rgba(0,0,0,.06);
  border-radius: var(--kc-radius-pill);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-soft);
}
nav li { margin: 0; }
nav a {
  display: inline-block;
  color: var(--kc-text);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 600;
  padding: .55rem 1rem;
  border-radius: var(--kc-radius-pill);
  background: var(--kc-surface);
  border: 1px solid rgba(0,0,0,.06);
  border-bottom-color: rgba(0,0,0,.12);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark);
  transition: transform 140ms ease, box-shadow 140ms ease, background 140ms ease, color 140ms ease;
  will-change: transform, box-shadow;
}
nav a:hover {
  transform: translateY(-2px);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-soft);
}
nav a:active {
  transform: translateY(0);
  box-shadow:
    inset 0 2px 6px rgba(0,0,0,.12),
    0 2px 0 rgba(255,255,255,.5);
}
nav a.active {
  color: #fff;
  background: linear-gradient(180deg, var(--kc-primary), var(--kc-primary-2));
  border-color: rgba(0,0,0,.02);
  box-shadow:
    inset 0 -2px 0 rgba(0,0,0,.12),
    var(--kc-shadow-strong),
    var(--kc-shadow-ring);
}

/* Theme toggle button styling */
nav .theme-toggle {
  display: inline-block;
  color: var(--kc-text);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 600;
  padding: .55rem 1rem;
  border-radius: var(--kc-radius-pill);
  background: var(--kc-surface);
  border: 1px solid rgba(0,0,0,.06);
  border-bottom-color: rgba(0,0,0,.12);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark);
  transition: transform 140ms ease, box-shadow 140ms ease, background 140ms ease, color 140ms ease;
  will-change: transform, box-shadow;
  cursor: pointer;
}

nav .theme-toggle:hover {
  transform: translateY(-2px);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-soft);
}

nav .theme-toggle:active {
  transform: translateY(0);
  box-shadow:
    inset 0 2px 6px rgba(0,0,0,.12),
    0 2px 0 rgba(255,255,255,.5);
}

nav .theme-toggle:focus-visible {
  outline: none;
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-ring);
}

/* Layout with improved spacing */
main {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0.5rem 1rem 1rem;
}

.category-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 1.8rem 0 1rem;
  color: var(--kc-text);
  text-transform: uppercase;
  letter-spacing: .3px;
  position: relative;
}

.category-title::after {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  margin-left: 8px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, var(--kc-primary), rgba(255,119,74,.25));
  box-shadow: 0 1px 2px rgba(0,0,0,.08);
  vertical-align: middle;
}

/* Grid */
.link-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(8rem, 1fr));
  gap: 1.1rem;
  margin-bottom: 2rem;
}

/* Card — keycap block */
.link-card {
  background: var(--kc-surface);
  border: 1px solid rgba(0,0,0,.06);
  border-bottom-color: rgba(0,0,0,.12);
  border-radius: var(--kc-radius-xl);
  padding: 1.1rem .9rem;
  text-align: center;
  transition: transform 140ms ease, box-shadow 140ms ease, background 140ms ease;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 90px;
  position: relative;
  overflow: hidden;
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-soft);
  transform: translateY(0);
}
.link-card:hover {
  transform: translateY(-3px);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-strong);
}
.link-card:active,
.link-card:has(a:active) {
  transform: translateY(0);
  box-shadow:
    inset 0 3px 8px rgba(0,0,0,.14),
    0 2px 0 rgba(255,255,255,.45);
}

/* Make the whole card clickable via inner <a> */
.link-card a {
  position: absolute;
  inset: 0;
  text-decoration: none;
  z-index: 2;
  display: block;
}

/* Card content */
.link-card i {
  font-size: 1.8rem;
  margin-bottom: .7rem;
  color: var(--kc-primary);
  filter:
    drop-shadow(0 1px 0 rgba(255,255,255,.5))
    drop-shadow(6px 8px 16px rgba(0,0,0,.12));
}
.link-card h3 {
  font-size: .9rem;
  margin: 0;
  color: var(--kc-text);
  line-height: 1.3;
  font-weight: 600;
  max-width: 100%;
  height: 2.6em;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  -webkit-box-orient: vertical;
  text-overflow: ellipsis;
  white-space: normal;
  padding: 0 .3rem;
}

/* Footer */
footer {
  background: transparent;
  color: var(--kc-text-weak);
  text-align: center;
  padding: 1rem;
  font-size: .75rem;
}
footer nav {
  margin-top: .6rem;
  background: transparent;
}
footer nav a {
  color: var(--kc-text);
  margin: 0 .6rem;
  font-size: .75rem;
  display: inline-block;
  padding: .35rem .6rem;
  border-radius: var(--kc-radius-pill);
  background: var(--kc-surface);
  border: 1px solid rgba(0,0,0,.06);
  border-bottom-color: rgba(0,0,0,.12);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark);
  transition: box-shadow 140ms ease, transform 140ms ease;
}
footer nav a:hover {
  transform: translateY(-1px);
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-soft);
}
footer nav a:focus-visible {
  outline: none;
  box-shadow:
    var(--kc-bevel-light),
    var(--kc-bevel-dark),
    var(--kc-shadow-ring);
}

/* Performance: GPU-accelerated animations */
.link-card,
nav a,
footer nav a {
  transform: translateY(0) translateZ(0);
  backface-visibility: hidden;
  perspective: 1000px;
}
/* Accessibility: reduce motion & improve focus */
@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;
  }
}

/* Enhanced focus states for better accessibility */
:focus-visible {
  outline: 2px solid var(--kc-primary);
  outline-offset: 2px;
  border-radius: 4px;
}

/* Skip link for screen readers */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--kc-primary);
  color: white;
  padding: 8px;
  text-decoration: none;
  border-radius: 4px;
  z-index: 10000;
}

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

/* Responsive */
@media (max-width: 1200px) {
  :root { --container-max: 95vw; }
  main {
    padding: 1rem;
    max-width: var(--container-max);
  }
  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(8rem, 1fr));
    gap: 1rem;
  }
}
@media (max-width: 768px) {
  html { font-size: 15px; }
  
  header { 
    padding: 1.5rem 0.8rem 1rem; 
  }
  
  header h1 { 
    font-size: 1.8rem; 
    letter-spacing: 0.8px;
  }
  
  main { padding: 0.5rem 0.8rem 1rem; }
  .link-grid { grid-template-columns: repeat(auto-fill, minmax(7rem, 1fr)); gap: .8rem; }
  nav { padding: .4rem 0 .8rem; justify-content: center; }
  nav a { padding: .45rem .85rem; font-size: .95rem; }
  .category-title { font-size: 1.3rem; margin: 1.5rem 0 1rem; }
  .link-card { padding: 1rem .7rem; min-height: 80px; }
  .link-card i { font-size: 1.6rem; margin-bottom: .5rem; }
  .link-card h3 { font-size: .8rem; height: 2.4em; }
}
@media (max-width: 480px) {
  html { font-size: 14px; }
  
  header { 
    padding: 1.2rem 0.6rem 0.8rem; 
  }
  
  header h1 { 
    font-size: 1.6rem; 
    letter-spacing: 0.6px;
  }
  
  main { padding: 0.4rem 0.6rem 1rem; }
  .link-grid { grid-template-columns: repeat(auto-fill, minmax(6rem, 1fr)); gap: .7rem; }
  nav ul { padding: .35rem; }
  nav a { padding: .4rem .7rem; font-size: .9rem; }
  .link-card { padding: .9rem .55rem; min-height: 70px; border-radius: var(--kc-radius-md); }
  .link-card i { font-size: 1.4rem; margin-bottom: .4rem; }
  .link-card h3 { font-size: .75rem; padding: 0 .2rem; height: 2.4em; }
  footer { padding: .8rem; }
  footer nav a { margin: 0 .4rem; font-size: .7rem; }
}
@media (max-width: 360px) {
  html { font-size: 13px; }
  
  header { 
    padding: 1rem 0.5rem 0.6rem; 
  }
  
  header h1 { 
    font-size: 1.4rem; 
    letter-spacing: 0.4px;
  }
  
  .link-grid { grid-template-columns: repeat(auto-fill, minmax(5.5rem, 1fr)); gap: .6rem; }
  main { padding: 0.3rem 0.5rem 1rem; }
  .link-card { padding: .8rem .5rem; min-height: 70px; }
  .link-card i { font-size: 1.3rem; margin-bottom: .3rem; }
  .link-card h3 { font-size: .7rem; padding: 0 .15rem; height: 2.2em; }
}