/* ===========================
   BuildUnitConverter - Main CSS
   =========================== */

/* --- Reset & Variables --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #1a56db;
  --primary-dark: #1040b0;
  --primary-light: #e8f0fe;
  --secondary: #f97316;
  --secondary-dark: #c2570e;
  --accent: #10b981;
  --dark: #111827;
  --gray-800: #1f2937;
  --gray-700: #374151;
  --gray-600: #4b5563;
  --gray-500: #6b7280;
  --gray-400: #9ca3af;
  --gray-300: #d1d5db;
  --gray-200: #e5e7eb;
  --gray-100: #f3f4f6;
  --gray-50: #f9fafb;
  --white: #ffffff;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow: 0 4px 12px rgba(0,0,0,0.10);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.14);
  --radius: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --transition: 0.2s ease;
}

html { scroll-behavior: smooth; font-size: 16px; }
body { font-family: var(--font); color: var(--gray-800); background: var(--white); line-height: 1.6; }
img { max-width: 100%; height: auto; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* --- Typography --- */
h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 800; line-height: 1.2; }
h2 { font-size: clamp(1.4rem, 3vw, 2rem); font-weight: 700; line-height: 1.3; }
h3 { font-size: clamp(1.1rem, 2vw, 1.4rem); font-weight: 600; }
h4 { font-size: 1.05rem; font-weight: 600; }
p { color: var(--gray-600); }

/* --- Layout --- */
.container { max-width: 1200px; margin: 0 auto; padding: 0 1.25rem; }
.container-sm { max-width: 800px; margin: 0 auto; padding: 0 1.25rem; }
.section { padding: 4rem 0; }
.section-lg { padding: 5rem 0; }

/* --- Header / Nav --- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
  box-shadow: var(--shadow-sm);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 0.5rem; font-weight: 800; font-size: 1.2rem; color: var(--dark); text-decoration: none; }
.logo-icon { width: 36px; height: 36px; background: var(--primary); border-radius: 8px; display: grid; place-items: center; color: white; font-size: 1.1rem; font-weight: 900; }
.logo span { color: var(--primary); }
.nav-links { display: flex; align-items: center; gap: 0.25rem; list-style: none; }
.nav-links a { padding: 0.4rem 0.75rem; border-radius: var(--radius); color: var(--gray-700); font-size: 0.9rem; font-weight: 500; transition: background var(--transition), color var(--transition); text-decoration: none; }
.nav-links a:hover, .nav-links a.active { background: var(--primary-light); color: var(--primary); }
.nav-cta { background: var(--primary) !important; color: var(--white) !important; padding: 0.45rem 1rem !important; }
.nav-cta:hover { background: var(--primary-dark) !important; text-decoration: none; }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.25rem; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--gray-700); margin: 5px 0; transition: var(--transition); }

/* --- Hero --- */
.hero { background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 50%, #1a56db 100%); color: white; padding: 5rem 0 4rem; text-align: center; position: relative; overflow: hidden; }
.hero::before { content: ''; position: absolute; inset: 0; background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E"); }
.hero-badge { display: inline-flex; align-items: center; gap: 0.4rem; background: rgba(255,255,255,0.12); border: 1px solid rgba(255,255,255,0.2); border-radius: 100px; padding: 0.35rem 0.9rem; font-size: 0.82rem; font-weight: 600; color: #93c5fd; margin-bottom: 1.25rem; }
.hero h1 { color: white; margin-bottom: 1rem; }
.hero h1 span { color: #60a5fa; }
.hero p { color: #bfdbfe; font-size: 1.1rem; max-width: 600px; margin: 0 auto 2rem; }
.hero-search { display: flex; gap: 0.5rem; max-width: 520px; margin: 0 auto 1.5rem; }
.hero-search input { flex: 1; padding: 0.85rem 1.1rem; border: 2px solid rgba(255,255,255,0.2); border-radius: var(--radius); background: rgba(255,255,255,0.1); color: white; font-size: 0.95rem; outline: none; transition: border-color var(--transition); }
.hero-search input::placeholder { color: rgba(255,255,255,0.5); }
.hero-search input:focus { border-color: rgba(255,255,255,0.5); }
.hero-search button { padding: 0.85rem 1.5rem; background: var(--secondary); border: none; border-radius: var(--radius); color: white; font-weight: 700; cursor: pointer; white-space: nowrap; transition: background var(--transition); }
.hero-search button:hover { background: var(--secondary-dark); }
.hero-stats { display: flex; justify-content: center; gap: 2rem; flex-wrap: wrap; margin-top: 1.5rem; }
.hero-stat { text-align: center; }
.hero-stat strong { display: block; font-size: 1.6rem; font-weight: 800; color: white; }
.hero-stat span { font-size: 0.8rem; color: #93c5fd; }

/* --- Buttons --- */
.btn { display: inline-flex; align-items: center; gap: 0.4rem; padding: 0.65rem 1.3rem; border-radius: var(--radius); font-weight: 600; font-size: 0.9rem; cursor: pointer; border: 2px solid transparent; transition: all var(--transition); text-decoration: none; }
.btn-primary { background: var(--primary); color: white; border-color: var(--primary); }
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); text-decoration: none; }
.btn-secondary { background: var(--secondary); color: white; border-color: var(--secondary); }
.btn-secondary:hover { background: var(--secondary-dark); text-decoration: none; }
.btn-outline { background: transparent; color: var(--primary); border-color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: white; text-decoration: none; }
.btn-ghost { background: transparent; color: var(--gray-600); border-color: var(--gray-300); }
.btn-ghost:hover { background: var(--gray-100); text-decoration: none; }
.btn-lg { padding: 0.85rem 1.75rem; font-size: 1rem; }
.btn-sm { padding: 0.4rem 0.85rem; font-size: 0.82rem; }
.btn-copy { background: var(--accent); color: white; border-color: var(--accent); padding: 0.45rem 0.9rem; font-size: 0.85rem; }
.btn-copy:hover { background: #059669; text-decoration: none; }
.btn-copy.copied { background: var(--gray-500); border-color: var(--gray-500); }

/* --- Cards --- */
.card { background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-lg); padding: 1.5rem; box-shadow: var(--shadow-sm); transition: box-shadow var(--transition), transform var(--transition); }
.card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.card-icon { width: 48px; height: 48px; border-radius: var(--radius); display: grid; place-items: center; font-size: 1.4rem; margin-bottom: 0.85rem; }

/* --- Tool Cards Grid --- */
.tools-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1.25rem; }
.tool-card { background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-lg); padding: 1.25rem 1.5rem; transition: all var(--transition); cursor: pointer; position: relative; overflow: hidden; }
.tool-card::before { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px; background: linear-gradient(90deg, var(--primary), var(--accent)); opacity: 0; transition: opacity var(--transition); }
.tool-card:hover { box-shadow: var(--shadow); transform: translateY(-3px); border-color: var(--primary); text-decoration: none; }
.tool-card:hover::before { opacity: 1; }
.tool-card h3 { font-size: 0.95rem; color: var(--dark); margin-bottom: 0.35rem; }
.tool-card p { font-size: 0.82rem; color: var(--gray-500); margin: 0; }
.tool-card-icon { font-size: 1.6rem; margin-bottom: 0.6rem; }
.tool-card .badge { display: inline-block; font-size: 0.7rem; font-weight: 700; padding: 0.15rem 0.5rem; border-radius: 100px; background: var(--primary-light); color: var(--primary); margin-bottom: 0.5rem; }
.tool-card .badge.new { background: #fef3c7; color: #d97706; }

/* --- Categories --- */
.categories-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 1rem; }
.category-card { background: var(--gray-50); border: 1px solid var(--gray-200); border-radius: var(--radius-lg); padding: 1.25rem; text-align: center; transition: all var(--transition); cursor: pointer; text-decoration: none; }
.category-card:hover { background: var(--primary-light); border-color: var(--primary); transform: translateY(-2px); text-decoration: none; }
.category-card .cat-icon { font-size: 2rem; margin-bottom: 0.5rem; display: block; }
.category-card h3 { font-size: 0.9rem; color: var(--dark); margin-bottom: 0.2rem; }
.category-card p { font-size: 0.78rem; color: var(--gray-500); margin: 0; }

/* --- Section Headers --- */
.section-header { text-align: center; margin-bottom: 2.5rem; }
.section-header .label { display: inline-block; font-size: 0.78rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--primary); background: var(--primary-light); padding: 0.3rem 0.85rem; border-radius: 100px; margin-bottom: 0.75rem; }
.section-header h2 { color: var(--dark); margin-bottom: 0.6rem; }
.section-header p { max-width: 540px; margin: 0 auto; color: var(--gray-500); }

/* --- Tool Page Layout --- */
.tool-page { padding: 2rem 0 4rem; }
.tool-header { background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); color: white; padding: 2.5rem 0; margin-bottom: 2.5rem; }
.tool-header h1 { color: white; font-size: clamp(1.5rem, 3vw, 2.2rem); margin-bottom: 0.5rem; }
.tool-header p { color: #bfdbfe; margin: 0; }
.tool-breadcrumb { font-size: 0.82rem; color: rgba(255,255,255,0.6); margin-bottom: 0.5rem; }
.tool-breadcrumb a { color: rgba(255,255,255,0.8); text-decoration: none; }
.tool-breadcrumb a:hover { color: white; }

.tool-main { display: grid; grid-template-columns: 1fr 300px; gap: 2rem; align-items: start; }
@media (max-width: 900px) { .tool-main { grid-template-columns: 1fr; } }

/* --- Converter Box --- */
.converter-box { background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-xl); padding: 2rem; box-shadow: var(--shadow); }
.converter-box h2 { font-size: 1.1rem; color: var(--dark); margin-bottom: 1.5rem; padding-bottom: 0.75rem; border-bottom: 1px solid var(--gray-200); }
.form-group { margin-bottom: 1.25rem; }
.form-group label { display: block; font-size: 0.85rem; font-weight: 600; color: var(--gray-700); margin-bottom: 0.4rem; }
.form-group input, .form-group select {
  width: 100%; padding: 0.75rem 1rem; border: 2px solid var(--gray-200);
  border-radius: var(--radius); font-size: 1rem; color: var(--dark);
  background: var(--gray-50); outline: none; transition: border-color var(--transition), background var(--transition);
  -moz-appearance: textfield;
}
.form-group input:focus, .form-group select:focus { border-color: var(--primary); background: white; }
.form-group input::-webkit-outer-spin-button, .form-group input::-webkit-inner-spin-button { -webkit-appearance: none; }
.input-with-unit { position: relative; }
.input-with-unit input { padding-right: 4.5rem; }
.input-unit { position: absolute; right: 1rem; top: 50%; transform: translateY(-50%); font-size: 0.82rem; font-weight: 700; color: var(--gray-500); pointer-events: none; }
.convert-arrow { display: flex; align-items: center; justify-content: center; margin: 0.5rem 0; }
.convert-arrow svg { width: 24px; height: 24px; color: var(--primary); }

.result-box { background: var(--primary-light); border: 2px solid var(--primary); border-radius: var(--radius-lg); padding: 1.25rem 1.5rem; margin: 1.25rem 0; }
.result-box .result-label { font-size: 0.8rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; color: var(--primary); margin-bottom: 0.35rem; }
.result-box .result-value { font-size: 2rem; font-weight: 800; color: var(--dark); word-break: break-all; }
.result-box .result-unit { font-size: 0.95rem; font-weight: 500; color: var(--gray-600); margin-left: 0.25rem; }
.result-box .result-actions { display: flex; gap: 0.5rem; margin-top: 0.75rem; flex-wrap: wrap; }

.quick-ref { background: var(--gray-50); border-radius: var(--radius-lg); padding: 1.25rem; margin-top: 1.25rem; }
.quick-ref h4 { font-size: 0.85rem; color: var(--gray-700); margin-bottom: 0.75rem; }
.quick-ref table { width: 100%; border-collapse: collapse; font-size: 0.82rem; }
.quick-ref td { padding: 0.35rem 0.5rem; border-bottom: 1px solid var(--gray-200); }
.quick-ref td:first-child { font-weight: 600; color: var(--primary); }
.quick-ref td:last-child { color: var(--gray-600); text-align: right; }

/* --- Sidebar --- */
.sidebar { display: flex; flex-direction: column; gap: 1.25rem; }
.sidebar-widget { background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-lg); padding: 1.25rem; }
.sidebar-widget h3 { font-size: 0.9rem; font-weight: 700; color: var(--dark); margin-bottom: 0.85rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--gray-200); }
.related-links { list-style: none; }
.related-links li { padding: 0.35rem 0; border-bottom: 1px solid var(--gray-100); }
.related-links li:last-child { border: none; }
.related-links a { font-size: 0.85rem; color: var(--gray-700); display: flex; align-items: center; gap: 0.35rem; text-decoration: none; }
.related-links a::before { content: '→'; color: var(--primary); font-size: 0.75rem; }
.related-links a:hover { color: var(--primary); }

/* --- Ad Placeholders --- */
.ad-unit { background: var(--gray-100); border: 2px dashed var(--gray-300); border-radius: var(--radius); display: flex; align-items: center; justify-content: center; text-align: center; color: var(--gray-400); font-size: 0.75rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; }
.ad-banner { height: 90px; margin: 1.5rem 0; }
.ad-rectangle { height: 250px; }
.ad-leaderboard { height: 90px; }

/* --- Why Section --- */
.why-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 1.5rem; }
.why-card { text-align: center; padding: 1.75rem 1.25rem; background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-lg); }
.why-card .why-icon { font-size: 2.5rem; margin-bottom: 0.85rem; }
.why-card h3 { color: var(--dark); margin-bottom: 0.4rem; font-size: 1rem; }
.why-card p { font-size: 0.85rem; }

/* --- FAQ --- */
.faq-list { max-width: 780px; margin: 0 auto; }
.faq-item { border: 1px solid var(--gray-200); border-radius: var(--radius-lg); margin-bottom: 0.75rem; overflow: hidden; }
.faq-question { width: 100%; background: white; border: none; padding: 1.1rem 1.25rem; text-align: left; font-size: 0.95rem; font-weight: 600; color: var(--dark); cursor: pointer; display: flex; justify-content: space-between; align-items: center; transition: background var(--transition); }
.faq-question:hover { background: var(--gray-50); }
.faq-question[aria-expanded="true"] { background: var(--primary-light); color: var(--primary); }
.faq-icon { font-size: 1.2rem; font-weight: 400; transition: transform var(--transition); flex-shrink: 0; margin-left: 0.5rem; }
.faq-question[aria-expanded="true"] .faq-icon { transform: rotate(45deg); }
.faq-answer { display: none; padding: 0 1.25rem 1.1rem; font-size: 0.9rem; color: var(--gray-600); border-top: 1px solid var(--gray-200); }
.faq-answer.open { display: block; }
.faq-answer p, .faq-answer li { font-size: 0.9rem; }
.faq-answer ul { margin: 0.5rem 0 0 1.25rem; }

/* --- Blog --- */
.blog-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1.5rem; }
.blog-card { background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-lg); overflow: hidden; transition: all var(--transition); }
.blog-card:hover { box-shadow: var(--shadow); transform: translateY(-3px); text-decoration: none; }
.blog-card-thumb { background: linear-gradient(135deg, var(--primary), var(--accent)); height: 160px; display: flex; align-items: center; justify-content: center; font-size: 3rem; }
.blog-card-body { padding: 1.25rem; }
.blog-card-body .tag { font-size: 0.72rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--primary); }
.blog-card-body h3 { font-size: 1rem; color: var(--dark); margin: 0.4rem 0 0.5rem; line-height: 1.4; }
.blog-card-body p { font-size: 0.83rem; color: var(--gray-500); margin-bottom: 0.85rem; }
.blog-card-body .meta { font-size: 0.78rem; color: var(--gray-400); display: flex; gap: 0.75rem; }

/* --- Article Page --- */
.article-layout { display: grid; grid-template-columns: 1fr 300px; gap: 2rem; align-items: start; }
@media (max-width: 900px) { .article-layout { grid-template-columns: 1fr; } }
.article-body h2 { color: var(--dark); margin: 2rem 0 0.75rem; font-size: 1.4rem; }
.article-body h3 { color: var(--dark); margin: 1.5rem 0 0.5rem; }
.article-body p { margin-bottom: 1rem; line-height: 1.75; }
.article-body ul, .article-body ol { margin: 0.75rem 0 1rem 1.5rem; }
.article-body li { margin-bottom: 0.4rem; font-size: 0.95rem; color: var(--gray-600); line-height: 1.6; }
.article-body .callout { background: var(--primary-light); border-left: 4px solid var(--primary); padding: 1rem 1.25rem; border-radius: 0 var(--radius) var(--radius) 0; margin: 1.25rem 0; }
.article-body .callout p { color: var(--primary-dark); margin: 0; font-size: 0.9rem; }
.article-body .tool-cta { background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: white; padding: 1.5rem; border-radius: var(--radius-lg); margin: 1.75rem 0; text-align: center; }
.article-body .tool-cta p { color: rgba(255,255,255,0.85); margin-bottom: 0.85rem; }
.article-meta { display: flex; gap: 1rem; flex-wrap: wrap; margin-bottom: 1.5rem; padding-bottom: 1.5rem; border-bottom: 1px solid var(--gray-200); }
.article-meta span { font-size: 0.82rem; color: var(--gray-500); display: flex; align-items: center; gap: 0.3rem; }

/* --- Features/Stats Bar --- */
.stats-bar { background: var(--dark); color: white; padding: 2.5rem 0; }
.stats-bar-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; text-align: center; }
.stats-bar-item strong { display: block; font-size: 2rem; font-weight: 800; color: #60a5fa; }
.stats-bar-item span { font-size: 0.85rem; color: #9ca3af; }

/* --- Footer --- */
.site-footer { background: var(--gray-800); color: var(--gray-300); padding: 3rem 0 1.5rem; }
.footer-grid { display: grid; grid-template-columns: 2fr repeat(3, 1fr); gap: 2.5rem; margin-bottom: 2rem; }
.footer-brand .logo { color: white; margin-bottom: 0.75rem; display: flex; }
.footer-brand p { font-size: 0.85rem; color: var(--gray-400); line-height: 1.6; }
.footer-col h4 { color: white; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 0.85rem; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 0.4rem; }
.footer-col a { font-size: 0.85rem; color: var(--gray-400); text-decoration: none; transition: color var(--transition); }
.footer-col a:hover { color: var(--white); }
.footer-bottom { border-top: 1px solid #374151; padding-top: 1.25rem; display: flex; justify-content: space-between; align-items: center; flex-wrap: gap; gap: 0.75rem; font-size: 0.8rem; color: var(--gray-500); }

/* --- Affiliate Box --- */
.affiliate-box { background: linear-gradient(135deg, #fef3c7, #fde68a); border: 1px solid #fbbf24; border-radius: var(--radius-lg); padding: 1.25rem; }
.affiliate-box h4 { color: #92400e; margin-bottom: 0.5rem; font-size: 0.9rem; }
.affiliate-box p { font-size: 0.82rem; color: #78350f; margin-bottom: 0.85rem; }
.affiliate-item { display: flex; align-items: center; gap: 0.75rem; padding: 0.6rem 0; border-bottom: 1px solid rgba(251,191,36,0.3); }
.affiliate-item:last-child { border: none; padding-bottom: 0; }
.affiliate-item .aff-icon { font-size: 1.4rem; }
.affiliate-item .aff-info { flex: 1; }
.affiliate-item .aff-info strong { display: block; font-size: 0.85rem; color: #92400e; }
.affiliate-item .aff-info span { font-size: 0.75rem; color: #a16207; }
.affiliate-item a { font-size: 0.78rem; font-weight: 700; color: var(--primary); white-space: nowrap; text-decoration: none; }
.affiliate-item a:hover { text-decoration: underline; }

/* --- Breadcrumbs --- */
.breadcrumbs { display: flex; align-items: center; gap: 0.4rem; font-size: 0.82rem; color: var(--gray-500); flex-wrap: wrap; margin-bottom: 1.5rem; }
.breadcrumbs a { color: var(--primary); text-decoration: none; }
.breadcrumbs a:hover { text-decoration: underline; }
.breadcrumbs span { color: var(--gray-400); }

/* --- Search Results --- */
.search-results { position: absolute; top: calc(100% + 0.5rem); left: 0; right: 0; background: white; border: 1px solid var(--gray-200); border-radius: var(--radius-lg); box-shadow: var(--shadow-lg); z-index: 200; max-height: 380px; overflow-y: auto; display: none; }
.search-results.open { display: block; }
.search-result-item { display: flex; align-items: center; gap: 0.75rem; padding: 0.75rem 1rem; border-bottom: 1px solid var(--gray-100); cursor: pointer; transition: background var(--transition); }
.search-result-item:hover { background: var(--gray-50); }
.search-result-item .sri-icon { font-size: 1.4rem; width: 32px; text-align: center; }
.search-result-item .sri-info strong { display: block; font-size: 0.88rem; color: var(--dark); }
.search-result-item .sri-info span { font-size: 0.78rem; color: var(--gray-500); }
.search-hero-wrap { position: relative; max-width: 520px; margin: 0 auto; }

/* --- Tabs --- */
.tabs { display: flex; gap: 0; border: 1px solid var(--gray-200); border-radius: var(--radius); overflow: hidden; margin-bottom: 1.5rem; }
.tab-btn { flex: 1; padding: 0.65rem 1rem; border: none; background: var(--gray-50); color: var(--gray-600); font-size: 0.85rem; font-weight: 600; cursor: pointer; transition: all var(--transition); }
.tab-btn.active { background: var(--primary); color: white; }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* --- Toast --- */
.toast { position: fixed; bottom: 1.5rem; right: 1.5rem; background: var(--dark); color: white; padding: 0.75rem 1.25rem; border-radius: var(--radius); font-size: 0.88rem; font-weight: 500; box-shadow: var(--shadow-lg); z-index: 9999; transform: translateY(100px); opacity: 0; transition: all 0.3s ease; }
.toast.show { transform: translateY(0); opacity: 1; }

/* --- Utilities --- */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-accent { color: var(--accent); }
.text-muted { color: var(--gray-500); }
.mt-1 { margin-top: 0.5rem; } .mt-2 { margin-top: 1rem; } .mt-3 { margin-top: 1.5rem; } .mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; } .mb-2 { margin-bottom: 1rem; } .mb-3 { margin-bottom: 1.5rem; } .mb-4 { margin-bottom: 2rem; }
.bg-light { background: var(--gray-50); }
.bg-dark { background: var(--dark); }
.divider { border: none; border-top: 1px solid var(--gray-200); margin: 2rem 0; }
.badge-pill { display: inline-block; padding: 0.2rem 0.6rem; border-radius: 100px; font-size: 0.72rem; font-weight: 700; }
.badge-blue { background: var(--primary-light); color: var(--primary); }
.badge-green { background: #d1fae5; color: #065f46; }
.badge-orange { background: #fef3c7; color: #d97706; }

/* --- Responsive --- */
@media (max-width: 768px) {
  .nav-links { display: none; position: fixed; inset: 64px 0 0; background: white; flex-direction: column; padding: 1rem; align-items: flex-start; overflow-y: auto; z-index: 99; border-top: 1px solid var(--gray-200); }
  .nav-links.open { display: flex; }
  .nav-links a { width: 100%; padding: 0.75rem 1rem; font-size: 1rem; }
  .nav-toggle { display: block; }
  .hero-stats { gap: 1rem; }
  .stats-bar-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
  .tool-main { grid-template-columns: 1fr; }
  .article-layout { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
}
@media (max-width: 480px) {
  .categories-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; }
  .stats-bar-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-search { flex-direction: column; }
}