/* ============================================================
   LENGOCMINH.VN — V2 "BẢN VẼ KỸ THUẬT" · 2026-08-29
   Concept: trang web như tờ bản vẽ của người thầy kỹ sư.
   Palette: mực xanh bản vẽ + vàng ong Bee + giấy kẻ ô kỹ thuật.
   Chỉ dùng cho index V2 — các trang trong vẫn dùng style.css cũ.
   ============================================================ */

:root{
  /* nét kẻ trên giấy */
  --net-dam:rgba(255,255,255,.14); /* nét kẻ trên mực */
  --do-focus:#C9524A;
  --f-display:"Bricolage Grotesque","Be Vietnam Pro",system-ui,sans-serif;
  --f-body:"Be Vietnam Pro",system-ui,-apple-system,sans-serif;
  --f-mono:"IBM Plex Mono","Courier New",monospace;
  --r:10px;
  --wrap:1120px;
}

*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}
body{
  font-family:var(--f-body);
  color:var(--muc);
  background:var(--giay);
  line-height:1.65;
  font-size:16px;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto}
a{color:var(--ong-dam)}
a:focus-visible,button:focus-visible{outline:3px solid var(--ong);outline-offset:2px}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 22px}

/* ---------- chữ ---------- */
h1,h2,h3{font-family:var(--f-display);line-height:1.18;letter-spacing:-.01em}
h1{font-size:clamp(1.9rem,4.2vw,3rem);font-weight:700}
h2{font-size:clamp(1.45rem,3vw,2.1rem);font-weight:700}
h3{font-size:1.08rem;font-weight:600}
.callout{
  font-family:var(--f-mono);font-size:.78rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--ong-dam);
  display:inline-flex;align-items:center;gap:10px;
}
.callout::before{content:"";width:26px;height:1px;background:var(--ong-dam);display:inline-block}
.dark .callout,.callout.on-dark{color:var(--ong)}
.dark .callout::before,.callout.on-dark::before{background:var(--ong)}

/* ---------- nav ---------- */
.nav{
  position:sticky;top:0;z-index:50;
  background:rgba(250,247,240,.92);backdrop-filter:blur(8px);
  border-bottom:1px solid var(--net);
}
.nav .wrap{display:flex;align-items:center;gap:18px;min-height:60px}
.logo{
  font-family:var(--f-display);font-weight:700;font-size:1.02rem;
  color:var(--muc);text-decoration:none;letter-spacing:.02em;white-space:nowrap;
  display:inline-flex;align-items:center;min-height:44px;
}
.logo span{color:var(--ong-dam)}
.nav ul{display:flex;gap:2px;list-style:none;margin-left:auto;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none}
.nav ul::-webkit-scrollbar{display:none}
.nav .item{
  display:inline-flex;align-items:center;min-height:44px;padding:0 12px;
  font-size:.88rem;color:var(--muc);text-decoration:none;white-space:nowrap;
  border-bottom:2px solid transparent;
}
.nav .item:hover,.nav .item.on{border-bottom-color:var(--ong-dam);color:var(--ong-dam)}
@media (hover:none){.nav .item:active{background:var(--giay-dam)}}

/* ---------- hero: tờ bản vẽ ---------- */
.hero{
  background:
    linear-gradient(rgba(255,255,255,.028) 1px,transparent 1px),
    linear-gradient(90deg,rgba(255,255,255,.028) 1px,transparent 1px),
    linear-gradient(180deg,var(--muc) 0%,var(--muc-sau) 100%);
  background-size:34px 34px,34px 34px,100% 100%;
  color:#fff;padding:64px 0 72px;position:relative;overflow:hidden;
}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:44px;align-items:center}
.hero .who{display:flex;align-items:center;gap:12px;margin-bottom:18px}
.hero .who img{width:52px;height:52px;border-radius:50%;border:2px solid var(--ong);object-fit:cover}
.hero .who span{color:var(--thep-nhat);font-size:.92rem}
.hero .who strong{color:#fff}
.hero h1{margin:12px 0 16px;color:#fff}
.hero h1 em{font-style:normal;color:var(--ong)}
.hero .lead{color:#D9E2EC;font-size:1.04rem;max-width:34em}
.hero .lead strong{color:#fff}
.hero-ctas{display:flex;flex-wrap:wrap;gap:12px;margin-top:26px}

.btn{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:48px;padding:0 22px;border-radius:8px;
  font-family:var(--f-body);font-weight:600;font-size:.95rem;
  text-decoration:none;cursor:pointer;border:1.5px solid transparent;
  transition:transform .15s ease,box-shadow .15s ease;
}
.btn-ong{background:var(--ong);color:#1A1A1A}
.btn-ong:hover{transform:translateY(-2px);box-shadow:0 8px 22px rgba(255,192,32,.28)}
.btn-vien{background:transparent;color:#fff;border-color:rgba(255,255,255,.35)}
.btn-vien:hover{border-color:var(--ong);color:var(--ong)}
.light .btn-vien{color:var(--muc);border-color:var(--net)}
.light .btn-vien:hover{border-color:var(--ong-dam);color:var(--ong-dam)}
@media (hover:none){
  .btn-ong:active{transform:scale(.97)}
  .btn-vien:active{background:rgba(255,255,255,.08)}
}

/* tờ bản vẽ (signature) */
.sheet{
  background:rgba(255,255,255,.035);
  border:1px solid var(--net-dam);
  border-radius:6px;padding:18px 18px 0;position:relative;
}
.sheet::before{ /* lỗ gáy bản vẽ */
  content:"";position:absolute;left:-1px;top:14%;bottom:14%;width:3px;
  background:repeating-linear-gradient(180deg,var(--ong) 0 6px,transparent 6px 26px);
  opacity:.5;
}
.sheet-head{
  display:flex;justify-content:space-between;align-items:center;
  font-family:var(--f-mono);font-size:.68rem;letter-spacing:.12em;
  color:var(--thep-nhat);text-transform:uppercase;margin-bottom:10px;
}
.sheet-head b{color:var(--ong);font-weight:600}
.sheet svg.draw{display:block;width:100%;height:auto}
.sheet svg.stamp{width:104px;height:104px}
.sheet .draw path,.sheet .draw line,.sheet .draw rect,.sheet .draw circle{
  stroke-dasharray:600;stroke-dashoffset:600;
  animation:ve 1.6s ease forwards;
}
.sheet .draw .d2{animation-delay:.35s}
.sheet .draw .d3{animation-delay:.7s}
@keyframes ve{to{stroke-dashoffset:0}}
.stamp{
  position:absolute;right:16px;top:52px;width:104px;height:104px;
  transform:rotate(8deg);opacity:0;animation:dong .5s .1s ease forwards;
}
@keyframes dong{
  from{transform:rotate(8deg) scale(1.6);opacity:0}
  60%{transform:rotate(8deg) scale(.94);opacity:1}
  to{transform:rotate(8deg) scale(1);opacity:1}
}
/* khung tên bản vẽ */
.titleblock{
  margin:14px -18px 0;border-top:1px solid var(--net-dam);
  display:grid;grid-template-columns:1fr 1fr 1fr;
  font-family:var(--f-mono);font-size:.7rem;
}
.titleblock div{padding:9px 12px;border-right:1px solid var(--net-dam)}
.titleblock div:last-child{border-right:0}
.titleblock .k{display:block;color:var(--thep-nhat);font-size:.6rem;letter-spacing:.12em;text-transform:uppercase}
.titleblock .v{color:#fff}
.titleblock .v.ong{color:var(--ong)}

/* ---------- tóm tắt nhanh (GEO best-answer-first) ---------- */
.tomtat{background:#fff;border-bottom:1px solid var(--net);padding:26px 0}
.tomtat p{max-width:52em;margin-top:8px;font-size:1.02rem}
.tomtat strong{color:var(--muc)}

/* ---------- section chung ---------- */
.block{padding:64px 0}
.block.dark{background:
  linear-gradient(rgba(255,255,255,.025) 1px,transparent 1px),
  linear-gradient(90deg,rgba(255,255,255,.025) 1px,transparent 1px),
  var(--muc);
  background-size:34px 34px,34px 34px;
  color:#fff;
}
.block.dark h2{color:#fff}
.block.dark p{color:#D9E2EC}
.block.giay-dam{background:
  linear-gradient(var(--net) 1px,transparent 1px),
  linear-gradient(90deg,var(--net) 1px,transparent 1px),
  var(--giay-dam);
  background-size:34px 34px,34px 34px;
  background-blend-mode:normal;
}
.block h2{margin:10px 0 8px}
.block .sub{color:var(--thep);max-width:42em}
.dark .sub{color:var(--thep-nhat)}

/* ---------- sổ ghi lỗi (pains) ---------- */
.fault-log{margin-top:22px;border:1px solid var(--net);border-radius:var(--r);background:#fff;overflow:hidden}
.fault-head{
  display:flex;justify-content:space-between;padding:10px 16px;
  background:var(--muc);color:var(--thep-nhat);
  font-family:var(--f-mono);font-size:.7rem;letter-spacing:.12em;text-transform:uppercase;
}
.fault-head b{color:var(--ong)}
.fault{
  display:flex;gap:14px;padding:15px 16px;border-top:1px solid var(--net);
  align-items:baseline;
}
.fault:first-of-type{border-top:0}
.fault .ma{font-family:var(--f-mono);font-size:.78rem;color:var(--ong-dam);white-space:nowrap}
.fault p{font-size:.96rem}
.fault strong{color:var(--muc)}
@media (hover:hover){.fault:hover{background:var(--giay)}}

/* ---------- thẻ ---------- */
.bento{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:24px}
.bento.b4{grid-template-columns:repeat(4,1fr)}
.card{
  background:#fff;border:1px solid var(--net);border-radius:var(--r);
  padding:20px;position:relative;
  transition:transform .18s ease,box-shadow .18s ease,border-color .18s ease;
}
.card:hover{transform:translateY(-4px);box-shadow:0 12px 28px rgba(16,38,63,.10);border-color:var(--ong)}
@media (hover:none){.card:active{transform:scale(.985);border-color:var(--ong)}}
.card h3{margin-bottom:8px}
.card p{font-size:.94rem;color:#3C4A5C}
.card a{font-weight:600;text-decoration:none}
.card a:hover{text-decoration:underline}
.dark .card{background:rgba(255,255,255,.045);border-color:var(--net-dam)}
.dark .card p{color:#D9E2EC}
.dark .card h3{color:#fff}
.dark .card:hover{border-color:var(--ong);box-shadow:0 12px 28px rgba(0,0,0,.35)}
.badge{
  display:inline-block;font-family:var(--f-mono);font-size:.66rem;
  letter-spacing:.1em;text-transform:uppercase;
  background:var(--ong);color:#1A1A1A;border-radius:4px;
  padding:3px 8px;margin-bottom:10px;
}
.badge.xam{background:var(--giay-dam);color:var(--muc);border:1px solid var(--net)}
.dark .badge.xam{background:transparent;color:var(--thep-nhat);border-color:var(--net-dam)}
.chips{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.chips span{
  font-family:var(--f-mono);font-size:.68rem;color:var(--thep);
  border:1px solid var(--net);border-radius:4px;padding:2px 7px;
}
.dark .chips span{color:var(--thep-nhat);border-color:var(--net-dam)}

/* ---------- sơ đồ 6 mảnh (dark) ---------- */
.mod-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:24px}
.mod{
  border:1px solid var(--net-dam);border-radius:var(--r);
  padding:18px;background:rgba(255,255,255,.035);position:relative;
  transition:border-color .18s ease,transform .18s ease;
}
.mod:hover{border-color:var(--ong);transform:translateY(-3px)}
@media (hover:none){.mod:active{border-color:var(--ong)}}
.mod .ma{
  font-family:var(--f-mono);font-size:.64rem;letter-spacing:.12em;
  color:var(--ong);display:block;margin-bottom:8px;
}
.mod h3{color:#fff;margin-bottom:6px}
.mod p{font-size:.92rem;color:#C5D2DE}
.mod a{color:var(--ong);font-weight:600;text-decoration:none}
.mod a:hover{text-decoration:underline}

/* ---------- dải số đo (stats) ---------- */
.dim-strip{
  border-top:1px solid var(--net);border-bottom:1px solid var(--net);
  background:#fff;padding:34px 0;
}
.dims{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap}
.dim{text-align:center;flex:1;min-width:130px;position:relative;padding:0 8px}
.dim + .dim::before{
  content:"";position:absolute;left:0;top:8%;bottom:8%;width:1px;
  background:repeating-linear-gradient(180deg,var(--net) 0 5px,transparent 5px 10px);
}
.dim .n{font-family:var(--f-display);font-size:2.1rem;font-weight:700;color:var(--muc)}
.dim .n small{font-size:1.1rem;color:var(--ong-dam)}
.dim .l{font-family:var(--f-mono);font-size:.68rem;letter-spacing:.08em;text-transform:uppercase;color:var(--thep);margin-top:4px}

/* ---------- quy trình 7 bước ---------- */
.steps{margin-top:26px;display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:0 34px}
.step{
  display:flex;gap:16px;padding:16px 0;border-bottom:1px dashed var(--net);
  align-items:baseline;
}
.step .num{
  font-family:var(--f-mono);font-size:.8rem;color:var(--ong-dam);
  border:1px solid var(--ong-dam);border-radius:4px;
  min-width:44px;text-align:center;padding:3px 0;
}
.step h3{font-size:1rem;margin-bottom:3px}
.step p{font-size:.9rem;color:var(--thep)}

/* ---------- trích dẫn ---------- */
.quote{background:var(--muc-sau);color:#fff;padding:72px 0;text-align:center;position:relative}
.quote blockquote{
  font-family:var(--f-display);font-weight:600;
  font-size:clamp(1.25rem,2.6vw,1.75rem);line-height:1.4;
  max-width:19em;margin:0 auto;
}
.quote blockquote::before{content:"“";color:var(--ong);font-size:1.4em;vertical-align:-.1em;margin-right:2px}
.quote blockquote::after{content:"”";color:var(--ong);font-size:1.4em;vertical-align:-.35em;margin-left:2px}
.quote cite{
  display:inline-block;margin-top:18px;font-style:normal;
  font-family:var(--f-mono);font-size:.75rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--ong);
}

/* ---------- CTA band ---------- */
.cta-band{background:var(--ong);padding:58px 0;color:#1A1A1A}
.cta-band h2{color:#1A1A1A;max-width:22em}
.cta-band p{max-width:44em;margin-top:10px;color:#3D3316}
.cta-band .btn-ong{background:var(--muc);color:#fff}
.cta-band .btn-ong:hover{box-shadow:0 8px 22px rgba(16,38,63,.3)}
.cta-band .btn-vien{color:#1A1A1A;border-color:rgba(26,26,26,.4)}
.cta-band .btn-vien:hover{border-color:#1A1A1A;color:#1A1A1A}

/* ---------- cta strip nhỏ ---------- */
.cta-strip{
  margin-top:26px;display:flex;flex-wrap:wrap;gap:16px;align-items:center;
  justify-content:space-between;background:#fff;
  border:1px solid var(--net);border-left:4px solid var(--ong);
  border-radius:var(--r);padding:18px 20px;
}
.cta-strip p{font-size:.96rem}

/* ---------- footer ---------- */
footer{background:var(--muc-sau);color:var(--thep-nhat);padding:46px 0 40px;font-size:.9rem}
footer a{color:#D9E2EC;text-decoration:none}
footer a:hover{color:var(--ong)}
.footer-links{display:flex;flex-wrap:wrap;gap:6px 18px;margin:14px 0}
.footer-links a{display:inline-flex;min-height:32px;align-items:center}
footer .small{font-family:var(--f-mono);font-size:.7rem;letter-spacing:.08em;margin-top:14px}
footer .zalo{color:var(--ong);font-weight:600}

/* ---------- dải huy hiệu giải thưởng ---------- */
.awards{background:var(--muc-sau);border-top:1px solid var(--net-dam);padding:20px 0}
.awards-row{display:flex;flex-wrap:wrap;gap:10px 12px;align-items:stretch}
.awards .lb{
  font-family:var(--f-mono);font-size:.68rem;letter-spacing:.12em;text-transform:uppercase;
  color:var(--ong);align-self:center;margin-right:6px;white-space:nowrap;
}
.aw{
  display:flex;gap:9px;align-items:center;
  border:1px solid var(--net-dam);border-radius:6px;padding:8px 12px;
  background:rgba(255,255,255,.03);flex:1 1 220px;min-width:0;
}
.aw .yr{font-family:var(--f-mono);font-size:.74rem;color:var(--ong);font-weight:500;white-space:nowrap}
.aw .tx{font-size:.82rem;color:#D9E2EC;line-height:1.35}

/* ---------- form nhận tài liệu ---------- */
.lead-box{
  display:grid;grid-template-columns:1.05fr .95fr;gap:30px;align-items:start;
  background:#fff;border:1px solid var(--net);border-radius:var(--r);
  border-top:4px solid var(--ong);padding:26px;margin-top:22px;
}
.lead-box ul{margin:14px 0 0 18px}
.lead-box li{font-size:.95rem;margin:7px 0;color:#3C4A5C}
.f-row{margin-bottom:14px}
.f-row label{display:block;font-size:.86rem;font-weight:600;margin-bottom:5px}
.f-row input,.f-row select{
  width:100%;min-height:46px;padding:10px 12px;
  border:1.5px solid var(--net);border-radius:7px;
  font-family:var(--f-body);font-size:.95rem;color:var(--muc);background:#fff;
}
.f-row input:focus,.f-row select:focus{outline:none;border-color:var(--ong);box-shadow:0 0 0 3px rgba(255,192,32,.22)}
.f-consent{display:flex;gap:9px;align-items:flex-start;font-size:.84rem;color:var(--thep);margin:6px 0 14px}
.f-consent input{width:18px;height:18px;margin-top:2px;flex:none;accent-color:var(--ong-dam)}
.f-note{font-size:.8rem;color:var(--thep);margin-top:10px}
.f-kq{
  display:none;margin-top:12px;padding:12px 14px;border-radius:7px;
  background:#FFF7E0;border:1px solid var(--ong);font-size:.9rem;
}
.f-kq.hien{display:block}
.f-kq.loi{background:#FDECEA;border-color:#C9524A}

/* ---------- bài viết (series/blog) ---------- */
.prose{max-width:46em}
.prose h2{margin:34px 0 10px}
.prose p{margin:12px 0;font-size:1.02rem}
.prose ol,.prose ul{margin:12px 0 12px 22px}
.prose li{margin:8px 0;font-size:1.02rem}
.prose .meta{font-family:var(--f-mono);font-size:.72rem;letter-spacing:.1em;text-transform:uppercase;color:var(--thep-nhat)}
.faq-item{border:1px solid var(--net);border-radius:var(--r);background:#fff;margin-top:10px;padding:4px 16px}
.faq-item summary{cursor:pointer;font-weight:600;padding:10px 0;list-style-position:outside}
.faq-item p{margin:0 0 12px;color:#3C4A5C}

/* ---------- reveal khi cuộn ---------- */
.lo{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease}
.lo.vao{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.lo{opacity:1;transform:none}}

/* ---------- mobile ---------- */
@media (max-width:900px){
  .hero-grid{grid-template-columns:1fr;gap:34px}
  .bento,.bento.b4,.mod-grid{grid-template-columns:1fr 1fr}
  .lead-box{grid-template-columns:1fr;gap:22px}
}
@media (max-width:620px){
  body{font-size:15.5px}
  .hero{padding:44px 0 52px}
  .bento,.bento.b4,.mod-grid{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .dims{flex-direction:column;gap:18px}
  .dim + .dim::before{display:none}
  .titleblock{grid-template-columns:1fr 1fr}
  .titleblock div:nth-child(2){border-right:0}
  .cta-strip{flex-direction:column;align-items:flex-start}
  .stamp{width:84px;height:84px;top:40px}
  .lead-box{padding:20px}
  .aw{flex:1 1 100%}
}