/* ==========================================================================
   ElectroMechCalc — shared site theme
   Single source of truth for typography, layout helpers, search UI,
   and dark/light theming. Every page links this file instead of
   carrying its own duplicated <style> block.

   Theme model: body.dark-theme / body.light-theme is toggled by
   site-nav.js. Everything themeable reads from the CSS custom
   properties defined below (--bg, --surface, --text, etc.) rather
   than hardcoded hex values, so there is exactly one place to change
   a color for both themes.
   ========================================================================== */

body { font-family: 'Inter', system-ui, sans-serif; }
h1, h2, h3, .font-display { font-family: 'Space Grotesk', system-ui, sans-serif; }
.font-mono { font-family: 'JetBrains Mono', monospace; }

.blueprint-grid {
  background-image:
    linear-gradient(#1f2f47 1px, transparent 1px),
    linear-gradient(90deg, #1f2f47 1px, transparent 1px);
  background-size: 42px 42px;
}

.calc-card {
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
}
.calc-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 28px rgba(11,18,32,0.10);
  border-color: #0ea5e9;
}

.formula-chip {
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  background: #eaf6fd;
  color: #0369a1;
  padding: 3px 9px;
  border-radius: 6px;
  display: inline-block;
}

details summary::-webkit-details-marker { display: none; }
details summary { list-style: none; cursor: pointer; }
details summary .plus { transition: transform .2s ease; }
details[open] summary .plus { transform: rotate(45deg); }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

.nav-dropdown .nav-dropdown-panel { display: none; }
.nav-dropdown.nav-dropdown-open .nav-dropdown-panel { display: block; }
.nav-dropdown-panel { padding-top: 10px; margin-top: -10px; }

.nav-dropdown-link {
  display: block;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--text);
}
.nav-dropdown-link:hover {
  background: rgba(14,165,233,.10);
  color: var(--accent);
}

.mobile-sublink {
  display: block;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 13px;
  color: var(--nav-text);
  opacity: 0.85;
}
.mobile-sublink:hover {
  background: rgba(14,165,233,.12);
  color: var(--accent);
  opacity: 1;
}

.mobile-dropdown summary::-webkit-details-marker { display: none; }
.mobile-dropdown summary { list-style: none; }
.mobile-dropdown summary .plus { transition: transform .2s ease; }
.mobile-dropdown[open] summary .plus { transform: rotate(45deg); }

.premium-disabled {
  cursor: not-allowed;
  opacity: 0.55;
  pointer-events: none;
  user-select: none;
}

/* ---------------------------- search bar --------------------------------- */

.search-wrap { position: relative; }

.search-input {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 8px 12px 8px 34px;
  font-size: 13px;
  width: 190px;
  outline: none;
  transition: .15s ease;
}
.search-input::placeholder { color: var(--text-2); }
.search-input:focus {
  width: 230px;
  border-color: #0ea5e9;
  background: rgba(255,255,255,0.1);
}

.search-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  color: #64748b;
  pointer-events: none;
}

/*
 * Visibility state: site-nav.js toggles the "hidden" class on
 * #searchResults directly (classList.add/remove("hidden")). The
 * rules below match that exact mechanism — no separate
 * ".search-wrap.has-results" wrapper class is used anywhere, so
 * there is only one signal that controls whether results show.
 */
.search-results {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 280px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  box-shadow: 0 14px 30px rgba(11,18,32,0.25);
  overflow: hidden;
  z-index: 60;
}
.search-results.hidden { display: none; }

.search-results a {
  display: block;
  padding: 10px 14px;
  font-size: 13px;
  color: var(--text);
  border-bottom: 1px solid var(--border);
}
.search-results a:last-child { border-bottom: none; }
.search-results a:hover { background: rgba(14,165,233,.10) !important; }

.search-empty {
  padding: 12px 14px;
  font-size: 12.5px;
  color: var(--text-2);
}

/* ---------------------------- article prose ------------------------------ */

.page-prose h2 {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text);
  margin-top: 1.75rem;
  margin-bottom: 0.6rem;
  font-family: 'Space Grotesk', system-ui, sans-serif;
}
.page-prose p { color: var(--text-2); line-height: 1.75; margin-bottom: 1rem; }
.page-prose strong { color: var(--text); }
.page-prose ul { margin: 0 0 1rem 1.25rem; color: var(--text-2); line-height: 1.75; }
.page-prose li { margin-bottom: 0.4rem; }

.nav-icon-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 9999px;
  flex-shrink: 0;
  box-shadow: 0 2px 5px rgba(0,0,0,0.25);
}

/* ---------------------------- theme switch -------------------------------- */

.theme-switch {
  width: 38px;
  height: 20px;
  border-radius: 9999px;
  background: #64748b;
  position: relative;
  transition: .2s ease;
  flex-shrink: 0;
}
.theme-switch-dot {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #fff;
  transition: .2s ease;
}
body.dark-theme .theme-switch { background: #0ea5e9; }
body.dark-theme .theme-switch-dot { transform: translateX(18px); }

/* ================= UNIVERSAL THEME (CSS custom properties) ================= */

:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-2: #f1f5f9;
  --text: #111827;
  --text-2: #475569;
  --border: #e5e7eb;
  --nav: #ffffff;
  --nav-text: #111827;
  --accent: #0ea5e9;
}

body.dark-theme {
  --bg: #0B1220;
  --surface: #111c2e;
  --surface-2: #0f172a;
  --text: #e2e8f0;
  --text-2: #94a3b8;
  --border: #1f2f47;
  --nav: #111c2e;
  --nav-text: #e2e8f0;
}

body {
  background: var(--bg) !important;
  color: var(--text) !important;
  transition: background-color .25s ease, color .25s ease;
}

.site-header {
  background: var(--nav) !important;
  border-color: var(--border) !important;
}

#mainNav, #mobileNav {
  color: var(--nav-text) !important;
  background: var(--nav) !important;
}

.nav-link, .mobile-link {
  color: var(--nav-text) !important;
  padding: 8px 12px;
  border-radius: 8px;
  transition: .15s ease;
}
.nav-link:hover, .mobile-link:hover {
  background: rgba(14,165,233,.12);
  color: var(--accent) !important;
}

.bg-white, .bg-gray-50 { background: var(--surface) !important; }
.border, .border-gray-100, .border-gray-200 { border-color: var(--border) !important; }
.text-gray-800, .text-brandDark { color: var(--text) !important; }
.text-gray-700, .text-gray-600, .text-gray-500 { color: var(--text-2) !important; }

footer {
  background: var(--surface) !important;
  border-top: 1px solid var(--border);
}