/* Mạch Gọn — giao diện. Chủ đề: bảng mạch đồng (nâu đỏ) trên nền xanh đêm. */
:root{
  --ink:#0b1220;--ink2:#1f2a44;--mut:#6b7a93;--line:#e5e9f2;--line2:#eef2f8;
  --bg:#f5f7fc;--card:#fff;
  --cu:#d97a28;--cu2:#f0a84b;--teal:#0d9488;--vio:#6d5efc;
  --ok:#15a34a;--bad:#dc2626;--warn:#d97706;
  --r:16px;--r2:22px;
  --sh1:0 1px 2px rgba(11,18,32,.05),0 4px 14px -8px rgba(11,18,32,.18);
  --sh2:0 2px 6px rgba(11,18,32,.06),0 18px 40px -22px rgba(11,18,32,.45);
  --ff:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;font:16.5px/1.65 var(--ff);color:var(--ink);background:var(--bg);-webkit-font-smoothing:antialiased}
a{color:var(--teal);text-underline-offset:2px}
img,svg{max-width:100%}
h1,h2,h3,h4{letter-spacing:-.022em;line-height:1.22}
::selection{background:#fde3c3}

/* ---------- Thanh trên ---------- */
.top{display:flex;align-items:center;gap:18px;padding:11px 22px;background:rgba(11,18,32,.92);backdrop-filter:saturate(1.4) blur(10px);color:#fff;position:sticky;top:0;z-index:20;border-bottom:1px solid rgba(255,255,255,.07)}
.top nav{display:flex;gap:20px;margin-left:auto;flex-wrap:wrap}
.top nav a{color:#b9c4d6;text-decoration:none;font-size:14.5px;font-weight:550;padding:4px 0;border-bottom:2px solid transparent}
.top nav a:hover{color:#fff;border-color:var(--cu2)}
.logo{color:#fff;text-decoration:none;font-weight:800;font-size:19.5px;letter-spacing:-.4px;display:inline-flex;align-items:center;gap:9px}
.logo .mk{width:26px;height:26px;border-radius:8px;background:linear-gradient(140deg,var(--cu2),var(--cu));display:grid;place-items:center;font-size:14px;box-shadow:0 2px 10px -2px rgba(217,122,40,.7)}
main{max-width:1120px;margin:0 auto;padding:22px 20px 40px}

/* ---------- Trang chủ ---------- */
.hero{position:relative;overflow:hidden;margin:6px 0 0;padding:58px 24px 44px;text-align:center;color:#fff;border-radius:28px;
  background:radial-gradient(900px 420px at 50% -10%,#1d2b4d 0%,#0b1220 62%),#0b1220;box-shadow:var(--sh2)}
.hero:before{content:"";position:absolute;inset:0;opacity:.5;pointer-events:none;
  background-image:linear-gradient(rgba(240,168,75,.10) 1px,transparent 1px),linear-gradient(90deg,rgba(240,168,75,.10) 1px,transparent 1px);
  background-size:34px 34px;mask-image:radial-gradient(600px 300px at 50% 20%,#000 20%,transparent 75%)}
.hero>*{position:relative}
.hero h1{font-size:clamp(30px,5.2vw,50px);margin:0 0 14px;letter-spacing:-.035em}
.hero h1 em{font-style:normal;background:linear-gradient(95deg,var(--cu2),#ffd79b);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p{color:#b6c2d6;font-size:17.5px;max-width:700px;margin:0 auto 26px}
.hero p b{color:#fff;font-weight:650}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font-size:13px;font-weight:650;letter-spacing:.04em;text-transform:uppercase;color:var(--cu2);background:rgba(240,168,75,.12);border:1px solid rgba(240,168,75,.3);padding:5px 13px;border-radius:999px;margin-bottom:18px}

.search{display:flex;gap:8px;max-width:720px;margin:0 auto;background:#fff;border:1px solid rgba(255,255,255,.16);border-radius:var(--r2);padding:7px;box-shadow:0 24px 60px -24px rgba(0,0,0,.65)}
.search input,.search textarea{flex:1;border:0;outline:0;font:inherit;font-size:17px;padding:11px 14px;background:transparent;min-width:0;resize:vertical;color:var(--ink)}
.search input::placeholder,.search textarea::placeholder{color:#93a0b5}
.search.big{flex-direction:column;border-radius:var(--r);padding:12px;border:1px solid var(--line);box-shadow:var(--sh1);background:#fff}
.search.big .row{display:flex;gap:8px;flex-wrap:wrap}
.search.big .row input{border:1px solid var(--line);border-radius:12px;font-size:15px;flex:1 1 180px}
.search.big textarea{border:1px solid var(--line);border-radius:12px;margin-bottom:8px;font-size:16px}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;background:linear-gradient(180deg,#1b2740,#0d1526);color:#fff;border:0;border-radius:13px;padding:12px 20px;font:inherit;font-weight:650;cursor:pointer;text-decoration:none;white-space:nowrap;box-shadow:0 1px 0 rgba(255,255,255,.12) inset,0 6px 16px -10px rgba(11,18,32,.9);transition:transform .12s,box-shadow .12s,background .12s}
.btn:hover{transform:translateY(-1px);box-shadow:0 1px 0 rgba(255,255,255,.14) inset,0 12px 22px -12px rgba(11,18,32,.9)}
.btn:active{transform:translateY(0)}
.btn[disabled]{opacity:.55;cursor:default;transform:none}
.btn.cu{background:linear-gradient(180deg,var(--cu2),var(--cu));box-shadow:0 1px 0 rgba(255,255,255,.35) inset,0 10px 22px -12px rgba(217,122,40,.95)}
.btn.ghost{background:#fff;color:var(--ink);border:1px solid var(--line);box-shadow:var(--sh1)}
.btn.ghost:hover{background:#fbfcfe;border-color:#cfd7e6}
.search .btn{border-radius:16px}

.chips{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin:20px auto 0;max-width:840px}
.chip{border:1px solid var(--line);background:#fff;border-radius:999px;padding:7px 15px;font:inherit;font-size:14px;cursor:pointer;color:var(--ink2);transition:.14s}
.chip:hover,.chip.on{border-color:var(--cu);color:#8a4b10;background:#fff7ec}
.hero .chip{background:rgba(255,255,255,.07);border-color:rgba(255,255,255,.18);color:#d7deea}
.hero .chip:hover{background:rgba(240,168,75,.16);border-color:var(--cu2);color:#fff}

/* ---------- Khối tin cậy ---------- */
.trust{display:grid;grid-template-columns:repeat(auto-fit,minmax(202px,1fr));gap:14px;margin:30px 0}
.trust div{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:18px;box-shadow:var(--sh1);position:relative;overflow:hidden}
.trust div:before{content:"";position:absolute;left:0;top:0;bottom:0;width:3px;background:linear-gradient(var(--cu2),var(--teal))}
.trust b{display:block;font-size:16.5px;margin-bottom:5px}
.trust p{margin:0;color:var(--ink2);font-size:14.5px;line-height:1.55}

/* ---------- Lưới thẻ mạch ---------- */
.rh{margin:34px 0 12px;font-size:23px;display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.rh small{font-size:12.5px;color:var(--ok);font-weight:650;background:#e9f9ef;border:1px solid #bdecce;padding:3px 10px;border-radius:999px}
.rh2{margin:26px 0 12px;font-size:19px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(305px,1fr));gap:16px}
.grid.best{grid-template-columns:1fr}
.card{display:flex;flex-direction:column;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:18px 19px;text-decoration:none;color:inherit;box-shadow:var(--sh1);transition:transform .16s,box-shadow .16s,border-color .16s}
.card:hover{border-color:#d4dcea;transform:translateY(-3px);box-shadow:var(--sh2)}
.card h3{margin:5px 0 7px;font-size:18.5px}
.card p{margin:0 0 14px;color:var(--ink2);font-size:14.5px;line-height:1.58;display:-webkit-box;-webkit-line-clamp:4;-webkit-box-orient:vertical;overflow:hidden}
.card-cat{font-size:11.5px;text-transform:uppercase;letter-spacing:.07em;color:var(--cu);font-weight:750}
.meta{display:flex;flex-wrap:wrap;gap:6px 14px;font-size:13px;color:var(--mut);margin-top:auto;padding-top:10px;border-top:1px dashed var(--line)}
.ok-pill{color:var(--ok);font-weight:700}

.ai-cta{display:flex;gap:16px;align-items:center;justify-content:space-between;flex-wrap:wrap;
  background:linear-gradient(135deg,#131d33,#0b1220);color:#e8edf6;border:1px solid rgba(240,168,75,.28);border-radius:var(--r2);padding:20px 22px;margin:26px 0;box-shadow:var(--sh2)}
.ai-cta b{color:#fff}
.ai-cta.big{padding:26px}

.alert{border-radius:14px;padding:13px 16px;margin:16px 0;font-size:15.5px}
.alert.bad{background:#fef3f2;border:1px solid #fecaca;color:#7f1d1d}
.alert.warn{background:#fffaeb;border:1px solid #fde68a;color:#7c4a03}
.alert.info{background:#eff8ff;border:1px solid #bfdcfe;color:#0b3a6b}
.alert ul{margin:6px 0 0;padding-left:20px}
.demo-note{border-left:4px solid var(--vio)}

/* ---------- Trang một mạch ---------- */
.crumbs{font-size:13.5px;color:var(--mut)}.crumbs a{color:var(--mut)}
.circuit h1{font-size:clamp(26px,4vw,38px);margin:10px 0 10px}
.lead{font-size:17.5px;color:var(--ink2);margin:0 0 14px;max-width:70ch}
.badges{display:flex;flex-wrap:wrap;gap:8px}
.badges span{background:#fff;border:1px solid var(--line);border-radius:999px;padding:5px 13px;font-size:14px;box-shadow:var(--sh1)}
.toc{display:flex;flex-wrap:wrap;gap:6px 16px;align-items:center;margin:18px 0;padding:11px 14px;border:1px solid var(--line);border-radius:999px;background:rgba(255,255,255,.86);backdrop-filter:blur(8px);position:sticky;top:60px;z-index:9;box-shadow:var(--sh1)}
.toc a{text-decoration:none;font-size:14.5px;color:var(--ink2);font-weight:550}
.toc a:hover{color:var(--cu)}
.toc .btn{margin-left:auto;padding:7px 14px;font-size:14px}
section{background:var(--card);border:1px solid var(--line);border-radius:var(--r2);padding:20px 22px;margin:18px 0;scroll-margin-top:120px;box-shadow:var(--sh1)}
section h2{margin:0 0 12px;font-size:21.5px;display:flex;align-items:center;gap:9px}
section h2:before{content:"";width:4px;height:20px;border-radius:3px;background:linear-gradient(var(--cu2),var(--cu));flex:none}
.pcb-sec h2:before,.verify h2:before{background:linear-gradient(var(--teal),#0f766e)}

.verify{border:1px solid #bdecce;background:linear-gradient(180deg,#f3fdf6,#fff)}
.verify.ai{border-color:#fde68a;background:linear-gradient(180deg,#fffbeb,#fff)}
.vgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:12px;margin-bottom:10px}
.vbox{background:#fff;border:1px solid var(--line);border-radius:14px;padding:12px 14px;border-left:4px solid var(--mut);display:flex;flex-direction:column;box-shadow:var(--sh1)}
.vbox.ok{border-left-color:var(--ok)}.vbox.bad{border-left-color:var(--bad)}.vbox.wait{border-left-color:var(--warn)}.vbox.na{border-left-color:var(--line)}
.vbox b{font-size:14px;color:var(--mut);font-weight:650}
.vbox span{font-weight:700;font-size:16px;margin:1px 0 3px}
.vbox small{color:var(--mut);font-size:12.5px;line-height:1.45}
.checks{margin:6px 0 0;padding-left:20px;font-size:14.5px}
.checks li.pass{color:var(--ok)}.checks li.warn{color:var(--warn)}.checks li.error{color:var(--bad)}
.warns{background:#fffaeb;border:1px solid #fde68a;border-radius:14px;padding:12px 14px;margin-top:12px;font-size:15px}
.warns ul{margin:6px 0 0;padding-left:20px}

.diagram-wrap{overflow:auto;border:1px solid var(--line);border-radius:14px;background:#fff;-webkit-overflow-scrolling:touch}
table{width:100%;border-collapse:collapse;font-size:14.5px;margin-top:12px}
th,td{text-align:left;padding:9px 10px;border-bottom:1px solid var(--line2);vertical-align:top}
th{font-size:12.5px;color:var(--mut);font-weight:700;text-transform:uppercase;letter-spacing:.04em}
tbody tr:hover{background:#fafbfe}
.wires tr{cursor:pointer}.wires tr.hl{background:#fff7ec}
.sw{display:inline-block;width:14px;height:14px;border-radius:5px;margin-right:7px;vertical-align:-2px;border:1px solid rgba(0,0,0,.15)}
.arr{color:var(--mut)}.bom .total td{font-weight:700;border-bottom:0;background:#fafbfe}
.buy{font-size:13px;white-space:nowrap;font-weight:600}

.steps{padding-left:0;list-style:none;counter-reset:s}
.steps li{counter-increment:s;margin:10px 0;border:1px solid var(--line);border-radius:14px;padding:12px 14px;transition:.15s}
.steps label{display:flex;gap:12px;cursor:pointer}
.steps input{width:20px;height:20px;margin-top:3px;flex:none;accent-color:var(--teal)}
.steps b:before{content:counter(s);display:inline-grid;place-items:center;width:22px;height:22px;border-radius:7px;background:#eef2f8;color:var(--ink2);font-size:12.5px;margin-right:8px;vertical-align:1px}
.steps li:has(input:checked){background:#f2fdf6;border-color:#bdecce}
.steps li:has(input:checked) b:before{background:var(--ok);color:#fff}
.progress{height:8px;background:#e8edf5;border-radius:99px;overflow:hidden;margin-top:8px}
.progress div{height:100%;width:0;background:linear-gradient(90deg,var(--teal),var(--ok));transition:width .3s}

.code{background:#0b1220;color:#dbe4f3;border-radius:14px;padding:16px;overflow:auto;max-height:520px;font:13px/1.55 ui-monospace,SFMono-Regular,Consolas,monospace;border:1px solid #1d2b45}
.code-actions{display:flex;gap:9px;margin:10px 0;flex-wrap:wrap}
.muted{color:var(--mut)}.mono{font-family:ui-monospace,Consolas,monospace}
.safety{background:linear-gradient(180deg,#fff7ed,#fff);border-color:#fed7aa}
.safety h2:before{background:linear-gradient(#fb923c,#ea580c)}
details{border-top:1px solid var(--line2);padding:10px 0}
details>summary{cursor:pointer;font-weight:650;list-style:none}
details>summary::-webkit-details-marker{display:none}
details>summary:before{content:"▸";color:var(--cu);margin-right:8px;display:inline-block;transition:transform .15s}
details[open]>summary:before{transform:rotate(90deg)}

/* ---------- Mạch in ---------- */
.bb-sec h2:before{background:linear-gradient(#60a5fa,#2563eb)}
.bb-wrap svg{max-height:none;min-width:820px}
.bb-note{margin:12px 0 0;padding-left:20px;color:var(--ink2);font-size:14.5px}
.bb-note li{margin:4px 0}
.pcb-sec .pcb-stats{margin:14px 0}
.pcb-views{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:16px;margin:14px 0}
.pcb-views figure{margin:0}
.pcb-views figcaption{font-size:13px;color:var(--mut);margin-bottom:7px}
.pcb-wrap{border:1px solid var(--line);border-radius:14px;background:#fff;padding:12px;overflow:auto;box-shadow:var(--sh1)}
.pcb-wrap svg{display:block;width:100%;height:auto;max-height:460px}
.pcb-guide h4{margin:16px 0 4px;font-size:15.5px;color:var(--ink)}
.pcb-guide ul{margin:4px 0 10px;padding-left:20px}
.pcb-guide li{margin:4px 0}
.pcb-guide p{margin:5px 0}

/* ---------- Thiết kế bằng AI ---------- */
.stages{list-style:none;padding:0;max-width:760px;margin:20px auto;background:#fff;border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--sh1);overflow:hidden}
.stages li{padding:11px 16px 11px 42px;position:relative;color:var(--mut);border-bottom:1px solid var(--line2);font-size:15.5px}
.stages li:last-child{border-bottom:0}
.stages li:before{content:"○";position:absolute;left:16px}
.stages li.run{color:var(--ink);font-weight:650;background:#fffdf7}
.stages li.run:before{content:"◌";animation:spin 1s linear infinite;display:inline-block;color:var(--cu)}
.stages li.ok{color:var(--ink2)}.stages li.ok:before{content:"✔";color:var(--ok)}
.stages li.bad{color:var(--bad)}.stages li.bad:before{content:"✖"}
.stages small{color:var(--mut);font-weight:400}
@keyframes spin{to{transform:rotate(360deg)}}

/* ---------- Bảng giá ---------- */
.plans{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}
.plan{background:#fff;border:1px solid var(--line);border-radius:var(--r2);padding:22px;box-shadow:var(--sh1);display:flex;flex-direction:column;position:relative}
.plan.hot{border:2px solid var(--cu);box-shadow:var(--sh2)}
.plan.hot:after{content:"Chọn nhiều nhất";position:absolute;top:-12px;left:22px;background:linear-gradient(180deg,var(--cu2),var(--cu));color:#fff;font-size:12px;font-weight:700;padding:4px 11px;border-radius:999px}
.plan h3{margin:0 0 6px;font-size:18px}
.plan .price{font-size:30px;font-weight:800;letter-spacing:-.03em}
.plan p{color:var(--ink2);font-size:14.5px;flex:1}
.paybox{display:flex;gap:20px;flex-wrap:wrap;align-items:center;background:#fff;border:1px solid var(--line);border-radius:var(--r2);padding:20px;margin-top:18px;box-shadow:var(--sh1)}
.filters{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0 18px}
.toast{position:fixed;left:50%;bottom:26px;transform:translateX(-50%);background:var(--ink);color:#fff;padding:12px 18px;border-radius:14px;z-index:50;box-shadow:var(--sh2);font-size:15px}

footer{border-top:1px solid var(--line);color:var(--mut);padding:30px 20px;font-size:14px;background:#fff;margin-top:30px}
footer .fin{max-width:1120px;margin:0 auto;display:flex;gap:18px;justify-content:space-between;flex-wrap:wrap;align-items:center}
footer a{color:var(--ink2)}

@media (max-width:720px){
  main{padding:14px 13px 30px}
  .hero{margin:4px 0 0;padding:38px 16px 30px;border-radius:20px}
  .top{padding:9px 13px;flex-wrap:wrap;gap:8px}
  .logo{font-size:18px}
  .top nav{gap:14px;margin-left:0;width:100%}
  .top nav a{font-size:13.5px}
  .ai-cta{flex-direction:column;align-items:flex-start}
  .toc{position:static;border-radius:14px}
  .search{flex-direction:column;border-radius:18px}
  .search input{font-size:16px}
  .search .btn{width:100%}
  section{padding:16px 15px;border-radius:var(--r)}
  .pcb-views{grid-template-columns:1fr}
}
@media print{
  .top,footer,.toc,.code-actions,.ai-cta,.buy,.btn,#dform,#dprog,.hero:before{display:none!important}
  section{break-inside:avoid;border:0;padding:0;box-shadow:none}
  body{background:#fff}
  .code{max-height:none;white-space:pre-wrap;background:#fff;color:#000;border:1px solid #ccc}
  .diagram{min-width:0}.pcb-wrap svg{max-height:none}.pcb-guide[open] summary{display:none}
}