/*
Theme Name: CalculateHub
Theme URI: https://example.com/calculatehub
Author: CalculateHub Team
Author URI: https://example.com
Description: A fast, clean, SEO-friendly WordPress theme for free online calculators, converters and everyday tools. Built for AdSense monetization and organic search traffic (US, Canada, UK, EU audiences).
Version: 1.0.0
Requires at least: 6.0
Tested up to: 6.6
Requires PHP: 7.4
License: GNU General Public License v2 or later
License URI: LICENSE
Text Domain: calculatehub
Tags: calculator, tools, blog, custom-colors, custom-logo, custom-menu, featured-images, translation-ready, accessibility-ready, responsive-layout
*/

/* =========================================================
   1. CSS VARIABLES / DESIGN TOKENS
   ========================================================= */
:root {
  --ch-primary: #2563EB;
  --ch-primary-dark: #1D4ED8;
  --ch-secondary: #0F172A;
  --ch-bg: #F8FAFC;
  --ch-card: #FFFFFF;
  --ch-text: #0F172A;
  --ch-muted: #64748B;
  --ch-success: #16A34A;
  --ch-error: #DC2626;
  --ch-border: #E2E8F0;
  --ch-radius: 12px;
  --ch-radius-sm: 8px;
  --ch-shadow: 0 1px 3px rgba(15,23,42,0.08), 0 1px 2px rgba(15,23,42,0.06);
  --ch-shadow-lg: 0 10px 25px rgba(15,23,42,0.08);
  --ch-font: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --ch-container: 1200px;
}

[data-theme="dark"] {
  --ch-primary: #3B82F6;
  --ch-primary-dark: #60A5FA;
  --ch-secondary: #F8FAFC;
  --ch-bg: #0B1220;
  --ch-card: #111827;
  --ch-text: #F1F5F9;
  --ch-muted: #94A3B8;
  --ch-success: #22C55E;
  --ch-error: #F87171;
  --ch-border: #1F2937;
}

/* =========================================================
   2. RESET / BASE
   ========================================================= */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--ch-font);
  color: var(--ch-text);
  background: var(--ch-bg);
  line-height: 1.6;
  font-size: 16px;
  transition: background .2s ease, color .2s ease;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--ch-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { line-height: 1.25; margin: 0 0 .5em; color: var(--ch-text); }
h1 { font-size: clamp(1.75rem, 3vw, 2.5rem); font-weight: 800; }
h2 { font-size: clamp(1.4rem, 2.5vw, 1.9rem); font-weight: 700; }
h3 { font-size: 1.15rem; font-weight: 700; }
p { margin: 0 0 1em; }
ul { padding-left: 1.2em; }
button { font-family: inherit; cursor: pointer; }

.container { max-width: var(--ch-container); margin: 0 auto; padding: 0 20px; }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; }
:focus-visible { outline: 3px solid var(--ch-primary); outline-offset: 2px; }
.skip-link { position: absolute; left: -9999px; top: 0; background: var(--ch-primary); color: #fff; padding: 10px 16px; z-index: 10000; border-radius: 0 0 8px 0; }
.skip-link:focus { left: 0; }

/* =========================================================
   3. HEADER
   ========================================================= */
.site-header { background: var(--ch-card); border-bottom: 1px solid var(--ch-border); position: sticky; top: 0; z-index: 500; }
.site-header .container { display: flex; align-items: center; justify-content: space-between; gap: 24px; height: 72px; }
.site-branding { display: flex; flex-direction: column; }
.site-title { font-size: 1.4rem; font-weight: 800; color: var(--ch-text); letter-spacing: -0.02em; }
.site-title span.brand-mark { color: var(--ch-primary); }
.site-tagline { font-size: .72rem; color: var(--ch-muted); margin: 0; }

.main-navigation { display: flex; }
.main-navigation ul { list-style: none; display: flex; gap: 4px; margin: 0; padding: 0; }
.main-navigation a { color: var(--ch-text); font-weight: 600; font-size: .95rem; padding: 10px 12px; border-radius: var(--ch-radius-sm); }
.main-navigation a:hover { background: var(--ch-bg); text-decoration: none; color: var(--ch-primary); }

.header-actions { display: flex; align-items: center; gap: 8px; }
.header-search-toggle, .theme-toggle, .menu-toggle {
  background: var(--ch-bg); border: 1px solid var(--ch-border); border-radius: var(--ch-radius-sm);
  width: 40px; height: 40px; display: flex; align-items: center; justify-content: center; color: var(--ch-text);
}
.menu-toggle { display: none; }

.header-search-panel { display: none; border-top: 1px solid var(--ch-border); background: var(--ch-card); }
.header-search-panel.is-open { display: block; }
.header-search-panel form { display: flex; gap: 8px; padding: 12px 0; }
.header-search-panel input[type="search"] { flex: 1; padding: 10px 14px; border-radius: var(--ch-radius-sm); border: 1px solid var(--ch-border); background: var(--ch-bg); color: var(--ch-text); }

/* =========================================================
   4. HERO
   ========================================================= */
.hero { padding: 56px 0 40px; text-align: center; background: linear-gradient(180deg, var(--ch-bg) 0%, var(--ch-card) 100%); }
.hero p.subheadline { color: var(--ch-muted); font-size: 1.05rem; max-width: 640px; margin: 0 auto 28px; }
.hero-search { max-width: 620px; margin: 0 auto; }
.hero-search form { display: flex; gap: 8px; background: var(--ch-card); padding: 8px; border-radius: 999px; box-shadow: var(--ch-shadow-lg); border: 1px solid var(--ch-border); }
.hero-search input[type="search"] { flex: 1; border: none; background: transparent; padding: 12px 16px; font-size: 1rem; color: var(--ch-text); }
.hero-search input[type="search"]:focus { outline: none; }
.hero-search button { background: var(--ch-primary); color: #fff; border: none; padding: 12px 22px; border-radius: 999px; font-weight: 700; }
.hero-search button:hover { background: var(--ch-primary-dark); }
.hero-popular { margin-top: 18px; display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
.hero-popular a { background: var(--ch-card); border: 1px solid var(--ch-border); padding: 6px 14px; border-radius: 999px; font-size: .85rem; color: var(--ch-text); font-weight: 600; }
.hero-popular a:hover { border-color: var(--ch-primary); color: var(--ch-primary); text-decoration: none; }

/* =========================================================
   5. SECTIONS / CARDS
   ========================================================= */
.section { padding: 48px 0; }
.section-header { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 24px; }
.section-header .see-all { font-weight: 700; font-size: .9rem; }

.grid { display: grid; gap: 16px; }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: var(--ch-card); border: 1px solid var(--ch-border); border-radius: var(--ch-radius);
  padding: 22px; box-shadow: var(--ch-shadow); display: flex; flex-direction: column; gap: 8px; transition: transform .15s ease, box-shadow .15s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--ch-shadow-lg); }
.card .card-icon { width: 44px; height: 44px; border-radius: 10px; background: #EFF6FF; color: var(--ch-primary); display: flex; align-items: center; justify-content: center; font-size: 1.3rem; }
[data-theme="dark"] .card .card-icon { background: rgba(59,130,246,.15); }
.card h3 { margin: 4px 0 0; }
.card p { color: var(--ch-muted); font-size: .92rem; margin: 0; flex: 1; }
.card .btn { align-self: flex-start; margin-top: 6px; }

.category-card { text-align: center; padding: 28px 16px; }
.category-card .card-icon { margin: 0 auto; }

.btn { display: inline-flex; align-items: center; gap: 6px; background: var(--ch-primary); color: #fff; padding: 10px 18px; border-radius: var(--ch-radius-sm); font-weight: 700; font-size: .9rem; border: none; }
.btn:hover { background: var(--ch-primary-dark); text-decoration: none; color: #fff; }
.btn-outline { background: transparent; color: var(--ch-primary); border: 1px solid var(--ch-primary); }
.btn-outline:hover { background: var(--ch-primary); color: #fff; }
.btn-secondary { background: var(--ch-bg); color: var(--ch-text); border: 1px solid var(--ch-border); }
.btn-secondary:hover { background: var(--ch-border); color: var(--ch-text); }

.why-list { list-style: none; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.why-list li { background: var(--ch-card); border: 1px solid var(--ch-border); border-radius: var(--ch-radius); padding: 18px; font-weight: 600; display: flex; gap: 10px; align-items: flex-start; }
.why-list li::before { content: "✓"; color: var(--ch-success); font-weight: 900; }

/* =========================================================
   6. BREADCRUMBS
   ========================================================= */
.breadcrumbs { font-size: .85rem; color: var(--ch-muted); margin-bottom: 16px; }
.breadcrumbs a { color: var(--ch-muted); }
.breadcrumbs a:hover { color: var(--ch-primary); }

/* =========================================================
   7. CALCULATOR PAGE
   ========================================================= */
.tool-page-header { padding: 32px 0 8px; }
.tool-intro { color: var(--ch-muted); max-width: 760px; }

.calculator-box {
  background: var(--ch-card); border: 1px solid var(--ch-border); border-radius: var(--ch-radius);
  box-shadow: var(--ch-shadow); padding: 28px; max-width: 640px; margin: 24px 0;
}
.calculator-box h2 { margin-top: 0; font-size: 1.2rem; }
.form-row { margin-bottom: 16px; }
.form-row label { display: block; font-weight: 700; font-size: .88rem; margin-bottom: 6px; }
.form-row .field-wrap { position: relative; display: flex; align-items: center; }
.form-row input[type="number"], .form-row input[type="text"], .form-row select {
  width: 100%; padding: 12px 14px; font-size: 1.05rem; border: 1px solid var(--ch-border);
  border-radius: var(--ch-radius-sm); background: var(--ch-bg); color: var(--ch-text);
}
.form-row input:focus, .form-row select:focus { outline: none; border-color: var(--ch-primary); box-shadow: 0 0 0 3px rgba(37,99,235,.15); }
.field-suffix { position: absolute; right: 14px; color: var(--ch-muted); font-weight: 600; pointer-events: none; }
.form-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 20px; }
.form-error { color: var(--ch-error); font-size: .85rem; margin-top: 6px; display: none; }
.form-error.is-visible { display: block; }

.result-box {
  margin-top: 22px; padding: 20px; background: var(--ch-bg); border: 1px dashed var(--ch-border);
  border-radius: var(--ch-radius-sm); display: none;
}
.result-box.is-visible { display: block; }
.result-box .result-label { font-size: .8rem; text-transform: uppercase; letter-spacing: .04em; color: var(--ch-muted); font-weight: 700; }
.result-box .result-value { font-size: 2rem; font-weight: 800; color: var(--ch-primary); margin: 4px 0; word-break: break-word; }
.result-box .result-detail { font-size: .85rem; color: var(--ch-muted); }
.copy-btn { display: inline-flex; align-items: center; gap: 6px; font-size: .8rem; background: none; border: 1px solid var(--ch-border); padding: 6px 10px; border-radius: 999px; color: var(--ch-text); }
.copy-btn.copied { border-color: var(--ch-success); color: var(--ch-success); }

.tool-content-section { padding: 24px 0; border-top: 1px solid var(--ch-border); }
.tool-content-section:first-of-type { border-top: none; }
.examples-list, .faq-list { list-style: none; padding: 0; }
.examples-list li { padding: 10px 0; border-bottom: 1px solid var(--ch-border); }
.faq-item { border-bottom: 1px solid var(--ch-border); padding: 14px 0; }
.faq-item summary { font-weight: 700; cursor: pointer; list-style: none; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; float: right; font-weight: 900; color: var(--ch-primary); }
.faq-item[open] summary::after { content: "−"; }
.faq-item p { margin-top: 10px; color: var(--ch-muted); }

.related-tools { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.related-tools a.card { text-decoration: none; }

/* =========================================================
   8. ADS
   ========================================================= */
.ad-slot {
  background: var(--ch-bg); border: 1px dashed var(--ch-border); border-radius: var(--ch-radius-sm);
  display: flex; align-items: center; justify-content: center; min-height: 90px;
  color: var(--ch-muted); font-size: .75rem; text-transform: uppercase; letter-spacing: .06em;
  margin: 24px 0; overflow: hidden;
}
.ad-slot-sidebar { min-height: 250px; }

/* =========================================================
   9. SIDEBAR / LAYOUT
   ========================================================= */
.layout-with-sidebar { display: grid; grid-template-columns: 1fr 300px; gap: 32px; align-items: start; }
.sidebar-widget { background: var(--ch-card); border: 1px solid var(--ch-border); border-radius: var(--ch-radius); padding: 18px; margin-bottom: 16px; }

/* =========================================================
   10. FOOTER
   ========================================================= */
.site-footer { background: var(--ch-secondary); color: #CBD5E1; margin-top: 48px; }
.site-footer .container { padding: 48px 20px 24px; }
.footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-bottom: 32px; }
.footer-grid h4 { color: #fff; font-size: .85rem; text-transform: uppercase; letter-spacing: .05em; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: 8px; }
.footer-grid a { color: #94A3B8; font-size: .88rem; }
.footer-grid a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid #1E293B; padding-top: 20px; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; font-size: .82rem; color: #94A3B8; }
.footer-social { display: flex; gap: 10px; }
.footer-social a { width: 32px; height: 32px; border-radius: 50%; background: #1E293B; display: flex; align-items: center; justify-content: center; color: #fff; }

/* =========================================================
   11. SEARCH RESULTS
   ========================================================= */
.search-results-list .card { flex-direction: row; align-items: center; }

/* =========================================================
   12. RESPONSIVE
   ========================================================= */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .related-tools { grid-template-columns: repeat(2, 1fr); }
  .layout-with-sidebar { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .main-navigation { display: none; }
  .menu-toggle { display: flex; }
  .grid-3, .grid-2, .why-list { grid-template-columns: 1fr; }
  .calculator-box { padding: 20px; }
  .site-header .container { height: 64px; }
}
@media (max-width: 480px) {
  .grid-4 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero { padding: 36px 0 28px; }
}

/* Mobile nav drawer */
.mobile-nav { display: none; position: fixed; inset: 0; background: rgba(15,23,42,.5); z-index: 900; }
.mobile-nav.is-open { display: block; }
.mobile-nav-panel { background: var(--ch-card); width: 82%; max-width: 320px; height: 100%; padding: 24px; overflow-y: auto; }
.mobile-nav-panel ul { list-style: none; padding: 0; margin: 0; }
.mobile-nav-panel li { border-bottom: 1px solid var(--ch-border); }
.mobile-nav-panel a { display: block; padding: 14px 4px; font-weight: 700; color: var(--ch-text); }
.mobile-nav-close { background: none; border: none; font-size: 1.4rem; float: right; color: var(--ch-text); }