/* AIFreeHub — Refined Dark Theme v3 */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  --bg: #0c0c0e;
  --bg-secondary: #131316;
  --bg-card: #18181c;
  --bg-card-hover: #1e1e24;
  --bg-elevated: #222228;
  --border: #2a2a32;
  --border-hover: #3a3a46;
  --text: #e8e6e3;
  --text-secondary: #9a9a9e;
  --text-muted: #5c5c64;
  --accent: #ff6b35;
  --accent-rgb: 255, 107, 53;
  --accent-light: #ff8a5c;
  --accent2: #f59e0b;
  --success: #10b981;
  --danger: #ef4444;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', ui-monospace, monospace;
  --radius: 10px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --container: 1160px;
  --header-h: 62px;
  --shadow: 0 2px 8px rgba(0,0,0,0.3), 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.4);
  --shadow-lg: 0 16px 48px rgba(0,0,0,0.5);
  --glow: 0 0 20px rgba(var(--accent-rgb), 0.15);
  --glow-text: 0 0 40px rgba(var(--accent-rgb), 0.3);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  /* Noise texture */
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.025'/%3E%3C/svg%3E");
  background-size: 256px 256px;
}

a { color: var(--accent); text-decoration: none; transition: color .15s; }
a:hover { color: var(--accent-light); }

/* ─── Skip Link ─── */
.skip-link { position: absolute; top: -100%; left: 1rem; background: var(--accent); color: #fff; padding: .5rem 1.2rem; border-radius: var(--radius); z-index: 9999; font-weight: 600; font-size: .85rem; }
.skip-link:focus { top: 1rem; }

/* ─── Header ─── */
.header {
  position: sticky; top: 0; z-index: 100;
  height: var(--header-h);
  background: rgba(12, 12, 14, 0.85);
  backdrop-filter: blur(20px) saturate(1.2);
  -webkit-backdrop-filter: blur(20px) saturate(1.2);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex; align-items: center; height: 100%;
  justify-content: space-between; gap: 1rem;
}

.header-actions { display: flex; align-items: center; gap: .5rem; }

.logo {
  font-weight: 800; font-size: 1.25rem;
  color: var(--text); flex-shrink: 0;
  letter-spacing: -.03em;
}
.logo strong { color: var(--accent); }

.nav { display: flex; gap: .15rem; }

.nav-link {
  padding: .45rem .9rem; font-size: .85rem; font-weight: 500;
  color: var(--text-secondary); border-radius: var(--radius);
  transition: all .15s;
}
.nav-link:hover { color: var(--text); background: var(--bg-elevated); }
.nav-link.active { color: var(--accent); background: rgba(var(--accent-rgb), .08); }

/* Lang select */
.i18n-select {
  appearance: none; -webkit-appearance: none;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 4px 24px 4px 10px;
  border-radius: 8px;
  font-size: 13px;
  cursor: pointer;
  font-family: inherit;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%235c5c64'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  transition: all .15s;
}
.i18n-select:hover { border-color: var(--text-muted); color: var(--text); }
.i18n-select:focus { outline: none; border-color: var(--accent); }
.i18n-select option { background: var(--bg-card); color: var(--text); }

.hamburger { display: none; flex-direction: column; gap: 5px; padding: .25rem; cursor: pointer; background: none; border: none; }
.hamburger span { display: block; width: 18px; height: 2px; background: var(--text); border-radius: 2px; transition: all .2s; }

@media (max-width: 768px) {
  .hamburger { display: flex; }
  .nav {
    position: fixed; top: 0; right: 0; height: 100vh; width: 260px;
    background: var(--bg-secondary);
    flex-direction: column; padding: 80px 1.25rem; gap: .25rem;
    transform: translateX(100%); transition: transform .3s cubic-bezier(.16,1,.3,1);
    box-shadow: -8px 0 30px rgba(0,0,0,0.5);
    border-left: 1px solid var(--border);
  }
  .nav.open { transform: translateX(0); }
  .nav-link { width: 100%; font-size: 1rem; padding: .7rem 1rem; }
}

/* ─── Main ─── */
.main { flex: 1; }
.container { max-width: var(--container); margin: 0 auto; padding: 0 1.5rem; }

/* ─── Hero ─── */
.hero {
  position: relative;
  text-align: center;
  padding: 6rem 0 5rem;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -20%; left: 50%; transform: translateX(-50%);
  width: 1000px; height: 600px;
  background: radial-gradient(ellipse, rgba(var(--accent-rgb), .07) 0%, transparent 70%);
  pointer-events: none;
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 900;
  letter-spacing: -.05em;
  line-height: 1.05;
  margin-bottom: 1.25rem;
}
.gradient {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  color: var(--text-secondary);
  font-size: 1.1rem;
  max-width: 520px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ─── Section ─── */
.section { padding: 4rem 0; }
.section-title {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -.03em;
  margin-bottom: 2rem;
  text-align: center;
}
.page-title {
  font-size: 1.75rem;
  font-weight: 800;
  letter-spacing: -.03em;
  margin-bottom: .35rem;
}

/* ─── Search ─── */
.search-input {
  width: 100%; max-width: 520px;
  padding: .8rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 100px;
  font-size: .9rem;
  color: var(--text);
  outline: none;
  transition: all .2s;
  margin-bottom: 2rem;
  display: block;
}
.search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(var(--accent-rgb), .12), var(--glow);
}
.search-input::placeholder { color: var(--text-muted); }

/* ─── Tools Grid ─── */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1rem;
}

.tool-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all .25s cubic-bezier(.16,1,.3,1);
  position: relative;
  overflow: hidden;
}
.tool-card::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(600px circle at var(--mouse-x, 50%) var(--mouse-y, 50%), rgba(var(--accent-rgb), .04), transparent 40%);
  pointer-events: none;
  opacity: 0;
  transition: opacity .3s;
}
.tool-card:hover {
  border-color: rgba(var(--accent-rgb), .4);
  background: var(--bg-card-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}
.tool-card:hover::before { opacity: 1; }

.card-head { margin-bottom: .4rem; }
.card-link {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  transition: color .15s;
}
.card-link:hover { color: var(--accent); }
.card-link.text-muted { color: var(--text-muted); }
.tool-card p { font-size: .85rem; color: var(--text-secondary); line-height: 1.6; }

/* ─── Category Grid ─── */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1rem;
}

.cat-card {
  display: flex; align-items: flex-start; gap: 1rem;
  padding: 1.25rem 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all .25s cubic-bezier(.16,1,.3,1);
  width: 100%; text-align: left;
  font: inherit; color: inherit;
}
.cat-card:hover {
  border-color: rgba(var(--accent-rgb), .4);
  background: var(--bg-card-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.cat-icon {
  font-size: 1.75rem;
  width: 48px; height: 48px;
  display: flex; align-items: center; justify-content: center;
  background: rgba(var(--accent-rgb), .06);
  border-radius: var(--radius);
  flex-shrink: 0;
}
.cat-body h3 { font-size: .95rem; font-weight: 600; margin-bottom: 2px; }
.cat-body p { font-size: .8rem; color: var(--text-secondary); margin-bottom: 4px; }
.cat-body small { font-size: .75rem; color: var(--text-muted); }

/* ─── Tool Detail ─── */
.tool-detail { padding: 3rem 0; }
.back-link {
  display: inline-flex; align-items: center; gap: .35rem;
  font-size: .85rem; color: var(--text-secondary);
  margin-bottom: 1.5rem; transition: color .15s;
}
.back-link:hover { color: var(--accent); }

.detail-card {
  text-align: center;
  padding: 3.5rem 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}
.detail-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
}
.detail-icon { font-size: 3.5rem; margin-bottom: 1rem; }
.detail-card h1 {
  font-size: 2rem; font-weight: 800;
  letter-spacing: -.03em; margin-bottom: .75rem;
}
.detail-desc {
  font-size: 1.05rem; color: var(--text-secondary);
  max-width: 480px; margin: 0 auto 1.5rem;
}
.detail-meta { margin-bottom: 1.5rem; }

.badge {
  display: inline-block;
  padding: .3rem .85rem;
  font-size: .75rem; font-weight: 600;
  color: var(--accent);
  background: rgba(var(--accent-rgb), .08);
  border: 1px solid rgba(var(--accent-rgb), .15);
  border-radius: 100px;
}

.btn {
  display: inline-flex; align-items: center; gap: .4rem;
  padding: .7rem 1.75rem;
  border-radius: var(--radius);
  font-weight: 600; font-size: .875rem;
  transition: all .2s;
  cursor: pointer; border: none;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), #e85d2b);
  color: #fff;
  box-shadow: 0 4px 12px rgba(var(--accent-rgb), .3);
}
.btn-primary:hover {
  background: linear-gradient(135deg, var(--accent-light), #ff7a45);
  color: #fff;
  box-shadow: 0 6px 20px rgba(var(--accent-rgb), .4);
  transform: translateY(-1px);
}
.btn-lg { padding: .85rem 2.25rem; font-size: 1rem; }

.detail-related h2 {
  font-size: 1.15rem; font-weight: 700; margin-bottom: 1.25rem;
}
.detail-related .tools-grid {
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* ─── Empty state ─── */
.empty-state {
  grid-column: 1 / -1;
  text-align: center; padding: 3rem;
  color: var(--text-muted); font-size: .9rem;
}

/* ─── About page ─── */
.narrow { max-width: 680px; margin: 0 auto; padding: 3rem 1.5rem; }

/* ─── Footer ─── */
.footer {
  margin-top: auto;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: .825rem;
  background: var(--bg-secondary);
}

/* ─── Scrollbar ─── */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-hover); }

/* ─── Selection ─── */
::selection { background: rgba(var(--accent-rgb), .25); color: var(--text); }

/* ─── Fade-in animation ─── */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}
.tool-card, .cat-card { animation: fadeInUp .4s ease-out both; }
.tool-card:nth-child(1) { animation-delay: .05s; }
.tool-card:nth-child(2) { animation-delay: .1s; }
.tool-card:nth-child(3) { animation-delay: .15s; }
.tool-card:nth-child(4) { animation-delay: .2s; }
.tool-card:nth-child(5) { animation-delay: .25s; }
.tool-card:nth-child(6) { animation-delay: .3s; }