/* ═══════════════════════════════════════════════════════
   ĐỔI SỐ THÀNH CHỮ — KTHDIGI GOLDEN TEMPLATE v2.0
   Zero-CDN · Dark/Light · Glassmorphism · CSS Grid
   ═══════════════════════════════════════════════════════ */
@font-face{font-family:'Phudu';src:url('https://kth-electric.com/wp-content/fonts/DT-Phudu/DTPhudu-Bold.woff') format('woff');font-weight:700;font-display:swap}
@font-face{font-family:'Ganh';src:url('https://kth-electric.com/wp-content/fonts/Ganh/Ganh%20Type-Regular.otf') format('opentype');font-weight:400;font-display:swap}

:root{
--p:#10b981;--p2:#059669;--p3:#047857;--pg:linear-gradient(135deg,#059669,#10b981,#34d399);
--bg:#f0fdf4;--bg2:#fff;--card:#fff;--txt:#1a202c;--txt2:#4a5568;--txt3:#718096;
--border:rgba(0,0,0,.06);--shadow:0 4px 24px rgba(0,0,0,.07);
--r:14px;--font-h:'Phudu',system-ui,sans-serif;--font-b:'Ganh',system-ui,sans-serif;
}
html.dark{
--bg:#0c1017;--bg2:#151b26;--card:rgba(22,30,44,.85);--txt:#e8e2d9;--txt2:#a3b1c6;--txt3:#6b7b8f;
--border:rgba(255,255,255,.06);--shadow:0 4px 24px rgba(0,0,0,.3);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:var(--font-b);background:var(--bg);color:var(--txt);line-height:1.6;transition:background .3s,color .3s}
.brand-font{font-family:var(--font-h)}
.container{max-width:1100px;margin:0 auto;padding:0 20px}
a{color:var(--p);text-decoration:none}

/* ─── NAV ─── */
.kth-nav{position:sticky;top:0;z-index:1000;background:rgba(255,255,255,.85);backdrop-filter:blur(20px) saturate(180%);border-bottom:1px solid var(--border);transition:.3s}
html.dark .kth-nav{background:rgba(15,20,30,.8)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:58px}
.nav-logo{font-family:var(--font-h);font-size:1.35rem;font-weight:700;color:var(--p);display:flex;align-items:center;gap:8px;text-decoration:none}
.nav-logo span{color:var(--txt)}
.nav-actions{display:flex;align-items:center;gap:8px}
.nav-actions a{font-weight:600;color:var(--txt2);font-size:.85rem;padding:7px 14px;border-radius:8px;transition:.2s}
.nav-actions a:hover{color:var(--p);background:rgba(16,185,129,.08)}
.btn-theme{width:36px;height:36px;border:none;background:rgba(16,185,129,.08);color:var(--p);border-radius:8px;cursor:pointer;font-size:1rem;transition:.2s;display:flex;align-items:center;justify-content:center}
.btn-theme:hover{background:var(--p);color:#fff}

/* ─── HERO ─── */
.hero{background:var(--pg);padding:clamp(28px,5vw,48px) 20px;text-align:center;color:#fff;position:relative;overflow:hidden}
.hero::before{content:'';position:absolute;inset:0;background:radial-gradient(circle at 20% 50%,rgba(255,255,255,.12) 0%,transparent 50%)}
.hero h1{font-family:var(--font-h);font-size:clamp(1.6rem,4vw,2.4rem);margin-bottom:10px;text-shadow:0 2px 8px rgba(0,0,0,.15)}
.hero p{font-size:1.05rem;opacity:.92;max-width:680px;margin:0 auto}
.hero-badges{display:flex;justify-content:center;gap:10px;margin-top:14px;flex-wrap:wrap}
.badge{background:rgba(255,255,255,.18);backdrop-filter:blur(8px);padding:5px 14px;border-radius:20px;font-size:.82rem;font-weight:600;border:1px solid rgba(255,255,255,.2)}

/* ─── MAIN GRID ─── */
.main-grid{display:grid;grid-template-columns:1fr 340px;gap:24px;margin-top:-28px;position:relative;z-index:10}
@media(max-width:920px){.main-grid{grid-template-columns:1fr;margin-top:20px}}

/* ─── CARD ─── */
.card{background:var(--card);border-radius:var(--r);padding:24px;box-shadow:var(--shadow);border:1px solid var(--border);margin-bottom:24px;transition:transform .2s,box-shadow .2s}
.card:hover{transform:translateY(-2px);box-shadow:0 8px 32px rgba(16,185,129,.1)}
.card h2{font-family:var(--font-h);font-size:1.3rem;color:var(--p3);margin-bottom:16px;padding-bottom:10px;border-bottom:2px solid rgba(16,185,129,.15);display:flex;align-items:center;gap:8px}
html.dark .card h2{color:var(--p)}

/* ─── INPUT ─── */
.input-wrap{position:relative;margin-bottom:18px}
.num-input{width:100%;padding:16px 50px 16px 20px;font-size:clamp(1.4rem,3vw,1.8rem);font-family:var(--font-h);color:var(--p3);background:var(--bg);border:2px solid rgba(16,185,129,.25);border-radius:12px;outline:none;transition:.3s;letter-spacing:2px}
html.dark .num-input{background:var(--bg2);color:var(--p)}
.num-input:focus{border-color:var(--p);box-shadow:0 0 0 4px rgba(16,185,129,.12)}
.num-input::placeholder{color:var(--txt3);font-size:1rem;letter-spacing:0}
.btn-clear{position:absolute;right:14px;top:50%;transform:translateY(-50%);width:30px;height:30px;border:none;background:rgba(0,0,0,.06);color:var(--txt3);border-radius:50%;cursor:pointer;display:none;align-items:center;justify-content:center;font-size:12px;transition:.2s}
.btn-clear:hover{background:#ef4444;color:#fff}
.btn-clear.show{display:flex}

/* ─── OPTIONS ─── */
.opts-row{display:flex;gap:14px;margin-bottom:20px;flex-wrap:wrap;align-items:center}
.seg-ctrl{display:inline-flex;background:rgba(16,185,129,.06);padding:3px;border-radius:8px}
.seg-ctrl label{padding:7px 16px;cursor:pointer;border-radius:6px;font-weight:600;color:var(--txt3);font-size:.85rem;transition:.3s}
.seg-ctrl input[type="radio"]{display:none}
.seg-ctrl label:has(input:checked){background:var(--card);color:var(--p);box-shadow:0 2px 6px rgba(0,0,0,.06)}
.switch-lbl{display:flex;align-items:center;gap:8px;cursor:pointer;font-weight:600;color:var(--txt2);font-size:.82rem;margin-left:auto}
.switch-track{position:relative;width:40px;height:22px;background:rgba(0,0,0,.12);border-radius:20px;transition:.3s}
.switch-track::after{content:'';position:absolute;top:2px;left:2px;width:18px;height:18px;background:#fff;border-radius:50%;transition:.3s;box-shadow:0 1px 3px rgba(0,0,0,.15)}
.switch-lbl input{display:none}
.switch-lbl input:checked+.switch-track{background:var(--p)}
.switch-lbl input:checked+.switch-track::after{transform:translateX(18px)}

/* ─── RESULT ─── */
.result-box{background:linear-gradient(135deg,rgba(16,185,129,.04),rgba(52,211,153,.08));border:1.5px dashed rgba(16,185,129,.35);border-radius:12px;padding:24px;position:relative;min-height:110px;transition:.3s}
.result-box:hover{border-color:var(--p);box-shadow:0 4px 18px rgba(16,185,129,.1)}
.result-text{font-size:clamp(1.1rem,2.5vw,1.35rem);color:var(--p3);font-weight:700;line-height:1.7;animation:fadeUp .4s ease-out}
html.dark .result-text{color:#34d399}
@keyframes fadeUp{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}
.btn-copy{position:absolute;top:14px;right:14px;background:var(--card);color:var(--p);border:1px solid rgba(16,185,129,.3);padding:7px 14px;border-radius:6px;cursor:pointer;font-weight:600;font-size:.8rem;transition:.2s;display:flex;align-items:center;gap:5px}
.btn-copy:hover{background:var(--p);color:#fff;transform:translateY(-1px);box-shadow:0 4px 10px rgba(16,185,129,.25)}
.btn-copy.copied{background:var(--p);color:#fff}

/* ─── INVOICE MOCKUP ─── */
.invoice-mock{background:#fffdf5;border:1px solid rgba(0,0,0,.08);padding:24px;margin-top:22px;position:relative;box-shadow:0 8px 24px rgba(0,0,0,.04);animation:slideUp .5s cubic-bezier(.16,1,.3,1);background-image:radial-gradient(rgba(0,0,0,.04) 1px,transparent 0);background-size:20px 20px}
html.dark .invoice-mock{background:#1e2430;background-image:radial-gradient(rgba(255,255,255,.03) 1px,transparent 0)}
.invoice-mock::before{content:'';position:absolute;top:0;left:0;width:100%;height:4px;background:repeating-linear-gradient(45deg,#ef4444,#ef4444 10px,transparent 10px,transparent 20px,#3b82f6 20px,#3b82f6 30px,transparent 30px,transparent 40px)}
.invoice-mock::after{content:'';position:absolute;bottom:-6px;left:0;right:0;height:6px;background-image:radial-gradient(circle at 10px 0,transparent 10px,#fffdf5 11px);background-size:20px 10px;background-repeat:repeat-x}
html.dark .invoice-mock::after{background-image:radial-gradient(circle at 10px 0,transparent 10px,#1e2430 11px)}
@keyframes slideUp{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}
.inv-stamp{position:absolute;right:12px;top:28px;border:3px solid rgba(239,68,68,.25);border-radius:50%;width:74px;height:74px;display:flex;align-items:center;justify-content:center;color:rgba(239,68,68,.4);font-weight:700;font-size:12px;transform:rotate(-15deg);pointer-events:none;text-align:center;line-height:1.2}
.inv-title{text-align:center;color:#ef4444;margin-bottom:18px;font-family:var(--font-h);font-size:1rem;letter-spacing:1px}
.inv-row{display:flex;justify-content:space-between;margin-bottom:10px;border-bottom:1px dotted rgba(0,0,0,.1);padding-bottom:5px;font-size:.85rem}
html.dark .inv-row{border-bottom-color:rgba(255,255,255,.08)}
.inv-lbl{color:var(--txt3)}
.inv-val{font-weight:700;color:var(--txt);font-size:.95rem}
.inv-text{font-weight:700;color:#1d4ed8;font-style:italic;font-size:1.1rem;line-height:1.6}
html.dark .inv-text{color:#60a5fa}

/* ─── QUICK PRESETS ─── */
.presets{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:18px}
.preset-btn{padding:6px 14px;border:1px solid rgba(16,185,129,.2);border-radius:20px;background:transparent;color:var(--txt2);font-size:.78rem;font-weight:600;cursor:pointer;transition:.2s;font-family:var(--font-b)}
.preset-btn:hover{background:var(--p);color:#fff;border-color:var(--p);transform:translateY(-1px)}

/* ─── STATS ROW ─── */
.stats-row{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}
.stat-item{text-align:center;padding:14px 10px;border-radius:10px;background:rgba(16,185,129,.04);border:1px solid rgba(16,185,129,.1)}
.stat-num{font-family:var(--font-h);font-size:1.2rem;color:var(--p);font-weight:700}
.stat-label{font-size:.72rem;color:var(--txt3);margin-top:3px}

/* ─── SEO CONTENT ─── */
.seo-content{margin-top:32px}
.seo-content h2{font-family:var(--font-h);font-size:1.25rem;color:var(--p3);border-left:4px solid var(--p);padding-left:14px;margin:28px 0 14px}
html.dark .seo-content h2{color:var(--p)}
.seo-content p,.seo-content li{font-size:.95rem;color:var(--txt2);line-height:1.7}
.seo-content ul{padding-left:20px;margin-bottom:16px}
.seo-content li{margin-bottom:8px}

/* ─── TABLE ─── */
.cmp-table{width:100%;border-collapse:collapse;margin:16px 0;font-size:.85rem;overflow:hidden;border-radius:10px;border:1px solid var(--border)}
.cmp-table th,.cmp-table td{padding:11px 14px;text-align:left;border-bottom:1px solid var(--border)}
.cmp-table th{background:rgba(16,185,129,.06);font-weight:700;color:var(--p3);font-size:.78rem;text-transform:uppercase;letter-spacing:.5px}
html.dark .cmp-table th{color:var(--p);background:rgba(16,185,129,.08)}
.cmp-table td{color:var(--txt2)}
.cmp-table tbody tr:hover{background:rgba(16,185,129,.03)}

/* ─── FAQ ─── */
.faq-section{margin-top:32px}
.faq-item{border-bottom:1px solid var(--border);padding:14px 0}
.faq-q{font-weight:700;color:var(--txt);cursor:pointer;display:flex;justify-content:space-between;align-items:center;font-size:.95rem}
.faq-q::after{content:'+';font-size:1.2rem;color:var(--p);transition:.3s}
.faq-item.open .faq-q::after{transform:rotate(45deg)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .3s ease;color:var(--txt2);font-size:.9rem;line-height:1.7}
.faq-item.open .faq-a{max-height:600px;padding-top:10px}

/* ─── RELATED ─── */
.related-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:14px;margin-top:16px}
.rel-card{background:var(--card);border:1px solid var(--border);border-radius:12px;padding:18px;text-align:center;transition:.2s;text-decoration:none;color:var(--txt)}
.rel-card:hover{transform:translateY(-3px);box-shadow:var(--shadow);border-color:rgba(16,185,129,.3)}
.rel-icon{font-size:1.6rem;display:block;margin-bottom:6px}
.rel-card h4{font-size:.85rem;margin-bottom:3px}
.rel-card p{font-size:.72rem;color:var(--txt3)}

/* ─── FOOTER ─── */
.kth-footer{background:var(--bg2);border-top:1px solid var(--border);margin-top:40px;padding:32px 0 16px;text-align:center}
html.dark .kth-footer{background:var(--bg2)}
.footer-inner{max-width:1100px;margin:0 auto;padding:0 20px}
.footer-brand{font-family:var(--font-h);color:var(--p);font-size:1rem;margin-bottom:6px}
.footer-author{font-size:.82rem;color:var(--txt3);margin-bottom:12px}
.footer-author a{color:var(--p)}
.footer-links{display:flex;justify-content:center;gap:16px;flex-wrap:wrap;margin-bottom:12px}
.footer-links a{color:var(--txt3);font-size:.8rem;font-weight:600;transition:.2s}
.footer-links a:hover{color:var(--p)}
.footer-social{display:flex;justify-content:center;gap:14px;margin-bottom:10px}
.footer-social a{color:var(--txt3);transition:.2s}
.footer-social a:hover{color:var(--p)}
.ic{width:18px;height:18px;fill:currentColor}
.footer-copy{font-size:.75rem;color:var(--txt3);margin-top:6px}

/* ─── UTILITY ─── */
@media(max-width:600px){
.stats-row{grid-template-columns:repeat(2,1fr)}
.nav-actions a span{display:none}
.hero h1{font-size:1.4rem}
}