@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  /* ─── Colors (Dark Theme) ─────────────────────────────── */
  --bg:           #0c0f14;
  --bg-elevated:  #12161e;
  --sidebar-bg:   #10141b;
  --card-bg:      rgba(18, 22, 30, 0.85);
  --input-bg:     rgba(255, 255, 255, 0.04);
  --hover-bg:     rgba(255, 255, 255, 0.06);
  --border:       rgba(255, 255, 255, 0.08);

  --text:         #e8ecf4;
  --text-muted:   #7b8498;

  --accent:       #10b981;
  --accent-dark:  #059669;
  --accent-glow:  rgba(16, 185, 129, 0.15);
  --accent-gradient: linear-gradient(135deg, #10b981, #06b6d4);
  --header-bg: rgba(12, 15, 20, 0.85);

  /* ─── Typography ──────────────────────────────────────── */
  --font-body:  'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono:  'JetBrains Mono', 'Fira Code', monospace;

  /* ─── Layout ──────────────────────────────────────────── */
  --header-h:   64px;
}

:root[data-theme='light'] {
  --bg: #f8fafc;
  --bg-elevated: #ffffff;
  --sidebar-bg: #ffffff;
  --card-bg: #ffffff;
  --input-bg: rgba(15, 23, 42, 0.04);
  --hover-bg: rgba(15, 23, 42, 0.08);
  --border: rgba(15, 23, 42, 0.12);
  --text: #0f172a;
  --text-muted: #475569;
  --accent: #047857;
  --accent-dark: #065f46;
  --accent-glow: rgba(16, 185, 129, 0.15);
  --accent-gradient: linear-gradient(135deg, #10b981, #06b6d4);
  --header-bg: rgba(255, 255, 255, 0.95);
}

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

html {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  line-height: 1.6;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s;
}
a:hover {
  color: var(--accent-dark);
}

/* ─── Layout Shell ───────────────────────────────────────── */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  background: var(--header-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text);
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}
.site-logo .logo-accent {
  color: var(--accent);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--text);
  font-weight: 600;
  font-size: 1rem;
  font-family: inherit;
  line-height: 1;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s, color 0.2s, box-shadow 0.2s;
}
.theme-toggle:hover {
  border-color: var(--accent);
}
.theme-toggle:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.floating-palette-controls {
  position: fixed;
  bottom: clamp(0.75rem, 2vw, 1.25rem);
  right: clamp(0.75rem, 2vw, 1.25rem);
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.2rem 0.45rem;
  border-radius: 999px;
  background: var(--bg-elevated);
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 16px 30px rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  z-index: 200;
}
.palette-dots {
  display: flex;
  gap: 0.25rem;
}
.palette-dot {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 1px solid transparent;
  padding: 0;
  background-size: 160%;
  background-position: center;
  cursor: pointer;
  transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
  overflow: hidden;
}
.palette-dot:hover {
  transform: translateY(-1px);
}
.palette-dot.active,
.palette-dot:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.palette-dot:focus-visible {
  outline: none;
}

@media (max-width: 520px) {
  .floating-palette-controls {
    gap: 0.2rem;
    padding: 0.18rem 0.35rem;
    right: 0.65rem;
  }
  .palette-dot {
    width: 26px;
    height: 26px;
  }
}

.hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0.25rem;
}

.site-body {
  display: flex;
  min-height: calc(100vh - var(--header-h));
  width: 100%;
  max-width: none;
  margin: 0;
  gap: clamp(1.25rem, 2vw, 2.5rem);
  padding: 0 clamp(1rem, 2vw, 2rem) 0 0;
  align-items: stretch;
}

.main-content {
  flex: 1;
  padding: clamp(1.5rem, 2vw, 3rem);
  width: 100%;
}

.site-footer {
  padding: 2rem;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

/* ─── Page Utilities ─────────────────────────────────────── */

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}
.breadcrumbs a {
  color: var(--text-muted);
}
.breadcrumbs a:hover {
  color: var(--accent);
}
.breadcrumbs .sep {
  opacity: 0.4;
}

.page-title {
  font-size: 1.8rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-subtitle {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 2rem;
  line-height: 1.5;
}

.section-heading {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 2.5rem 0 1rem;
  color: var(--text);
}

/* ─── Category Grid ──────────────────────────────────────── */

.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 1rem;
}

/* ─── Calculator List (category page) ────────────────────── */

.calc-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 0.75rem;
}
.calc-list-item {
  display: block;
  padding: 1rem 1.25rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: border-color 0.2s, transform 0.15s, box-shadow 0.2s;
}
.calc-list-item:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
  color: var(--accent);
}

/* ─── Related Converters ─────────────────────────────────── */

.related-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.related-chip {
  padding: 0.4rem 0.85rem;
  font-size: 0.8rem;
  background: var(--hover-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-muted);
  text-decoration: none;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.related-chip:hover {
  background: var(--accent-glow);
  color: var(--accent);
  border-color: var(--accent);
}

/* ─── SEO Content ────────────────────────────────────────── */

.seo-content {
  margin-top: 2.5rem;
  padding: 2rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  line-height: 1.7;
  color: var(--text-muted);
  font-size: 0.92rem;
}
.seo-content h3 {
  color: var(--text);
  font-size: 1rem;
  margin-bottom: 0.75rem;
}
.seo-content p + p {
  margin-top: 1rem;
}

/* ─── Hero ───────────────────────────────────────────────── */

.hero {
  text-align: center;
  padding: 3rem 1rem 2rem;
  margin-bottom: 1rem;
}
.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 0.75rem;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 500px;
  margin: 0 auto 1.5rem;
}
.hero .search-center {
  display: flex;
  justify-content: center;
}

/* ─── Stats Row ──────────────────────────────────────────── */

.stats-row {
  display: flex;
  justify-content: center;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
  padding: 1rem 0;
}
.stat {
  text-align: center;
}
.stat-num {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--accent);
}
.stat-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* ─── Responsive ─────────────────────────────────────────── */

@media (max-width: 768px) {
  .hamburger {
    display: block;
  }
  .main-content {
    padding: 1.25rem;
  }
  .hero h1 {
    font-size: 1.8rem;
  }
  .category-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  }
  .stats-row {
    gap: 1.5rem;
  }
  .site-body {
    gap: 1rem;
    padding-inline: 1rem;
  }
}