/* =========================================================
   CƠ KHÍ — Website giới thiệu & catalog gia công cơ khí
   Design tokens
   ========================================================= */
:root{
  --ink:        #1B2430;   /* nền tối / chữ chính */
  --ink-2:      #2C3846;
  --steel:      #3D5A73;   /* xanh thép - accent phụ */
  --steel-light:#8B95A1;   /* xám thép - đường kẻ, phụ đề */
  --paper:      #F2F3F4;   /* nền sáng, xám lạnh (không dùng be/cream) */
  --paper-2:    #E7E9EB;
  --white:      #FFFFFF;
  --accent:     #F2A71B;   /* vàng an toàn công nghiệp */
  --accent-dark:#C9820A;
  --line:       #D3D7DA;
  --line-dark:  #3A4552;
  --danger:     #C0392B;

  --font-display: 'Oswald', 'Arial Narrow', sans-serif;
  --font-body:    'Inter', -apple-system, sans-serif;
  --font-mono:    'IBM Plex Mono', 'Courier New', monospace;

  --radius: 2px;
  --container: 1180px;
}

*,*::before,*::after{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{
  margin:0;
  font-family:var(--font-body);
  color:var(--ink);
  background:var(--paper);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
img{ max-width:100%; display:block; }
a{ color:inherit; text-decoration:none; }
ul{ margin:0; padding:0; list-style:none; }
h1,h2,h3,h4{
  font-family:var(--font-display);
  text-transform:uppercase;
  letter-spacing:.02em;
  margin:0 0 .5em;
  color:var(--ink);
}
p{ margin:0 0 1em; }
.container{
  max-width:var(--container);
  margin:0 auto;
  padding:0 24px;
}
:focus-visible{
  outline:3px solid var(--accent);
  outline-offset:2px;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce){
  *{ animation-duration:.001ms !important; animation-iteration-count:1 !important; transition-duration:.001ms !important; }
}

/* =========================================================
   Utility: eyebrow / spec label kiểu bản vẽ kỹ thuật
   ========================================================= */
.eyebrow{
  font-family:var(--font-mono);
  font-size:.75rem;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--steel);
  display:flex;
  align-items:center;
  gap:10px;
  margin-bottom:10px;
}
.eyebrow::before{
  content:"";
  width:24px;
  height:2px;
  background:var(--accent);
  display:inline-block;
}

/* =========================================================
   HEADER
   ========================================================= */
.site-header{
  position:sticky; top:0; z-index:100;
  background:var(--ink);
  border-bottom:3px solid var(--accent);
}
.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  height:76px;
}
.brand{
  display:flex;
  align-items:center;
  gap:12px;
  color:var(--white);
}
.brand-mark{
  width:60px;height:60px;
  flex:none;
  border:2px solid var(--white);
  border-radius:50%;
  background:var(--white);
  padding:2px;
}
.brand-text{
  font-family:var(--font-display);
  font-size:1.15rem;
  letter-spacing:.04em;
  text-transform:uppercase;
  line-height:1.1;
}
.brand-text small{
  display:block;
  font-family:var(--font-mono);
  font-size:.62rem;
  color:var(--steel-light);
  letter-spacing:.1em;
  text-transform:none;
  margin-top:2px;
}
.brand-text .company-name-placeholder{
  color: var(--accent);
}

.main-nav{ display:flex; align-items:center; gap:2px; }
.main-nav a{
  color:var(--white);
  font-family:var(--font-display);
  font-size:.85rem;
  letter-spacing:.06em;
  text-transform:uppercase;
  padding:10px 16px;
  border-bottom:2px solid transparent;
  transition:.15s;
}
.main-nav a:hover, .main-nav a.active{
  color:var(--accent);
  border-bottom-color:var(--accent);
}
.nav-toggle{
  display:none;
  background:none; border:none;
  color:var(--white);
  font-size:1.6rem;
  cursor:pointer;
  padding:6px 10px;
}

@media (max-width: 880px){
  .main-nav{
    position:fixed; inset:76px 0 0 0;
    background:var(--ink);
    flex-direction:column;
    align-items:stretch;
    gap:0;
    transform:translateX(100%);
    transition:transform .25s ease;
    overflow-y:auto;
    padding:10px 0 40px;
  }
  .main-nav.open{ transform:translateX(0); }
  .main-nav a{
    padding:16px 24px;
    border-bottom:1px solid var(--ink-2);
    font-size:1rem;
  }
  .nav-toggle{ display:block; }
}

/* =========================================================
   HERO — bản vẽ kỹ thuật + bánh răng chuyển động
   ========================================================= */
.hero{
  position:relative;
  background:var(--ink);
  color:var(--white);
  overflow:hidden;
  padding:90px 0 70px;
}
.hero::before{
  content:"";
  position:absolute; inset:0;
  background-image:
    linear-gradient(var(--line-dark) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-dark) 1px, transparent 1px);
  background-size:40px 40px;
  opacity:.35;
  mask-image:linear-gradient(to bottom, black, transparent 85%);
}
.hero-grid{
  position:relative;
  display:grid;
  grid-template-columns:1.1fr .9fr;
  gap:40px;
  align-items:center;
}
.hero-eyebrow{
  font-family:var(--font-mono);
  font-size:.8rem;
  letter-spacing:.15em;
  color:var(--accent);
  text-transform:uppercase;
  margin-bottom:18px;
}
.hero h1{
  color:var(--white);
  font-size:clamp(2.1rem, 4.5vw, 3.4rem);
  line-height:1.5;
  max-width:100ch;
}
.hero h1 .accent{ color:var(--accent); }
.hero p.lead{
  color:var(--steel-light);
  font-size:1.05rem;
  max-width:52ch;
  margin:18px 0 30px;
}
.hero-actions{ display:flex; gap:14px; flex-wrap:wrap; }
.hero-figure{
  position:relative;
  display:flex;
  align-items:center;
  justify-content:center;
}
.hero-figure svg{
  width:280px;
  max-width:100%;
  height:auto; /* giữ đúng tỉ lệ viewBox, không bị méo hình */
}
/* transform-origin thực tế được set inline theo toạ độ tâm từng bánh răng (xem HTML),
   quy tắc dưới đây chỉ là giá trị dự phòng */
.gear-spin{ animation:spin 25s linear infinite; transform-origin:center; }
.gear-spin.reverse{ animation-direction:reverse; animation-duration:17.5s; }
@keyframes spin{ to{ transform:rotate(360deg); } }

.hero-stats{
  position:relative;
  display:grid;
  grid-template-columns:repeat(4,1fr);
  border-top:1px solid var(--line-dark);
  margin-top:60px;
  padding-top:28px;
}
.hero-stats div{ text-align:left; padding-right:16px; }
.hero-stats strong{
  display:block;
  font-family:var(--font-display);
  font-size:1.9rem;
  color:var(--accent);
}
.hero-stats span{
  font-family:var(--font-mono);
  font-size:.72rem;
  color:var(--steel-light);
  text-transform:uppercase;
  letter-spacing:.08em;
}

@media (max-width:880px){
  .hero-grid{ grid-template-columns:1fr; }
  .hero-figure{ order:-1; max-width:220px; margin:0 auto 20px; }
  .hero-stats{ grid-template-columns:repeat(2,1fr); row-gap:20px; }
}

/* =========================================================
   BUTTONS
   ========================================================= */
.btn{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-display);
  font-size:.85rem;
  letter-spacing:.06em;
  text-transform:uppercase;
  padding:14px 26px;
  border-radius:var(--radius);
  border:2px solid transparent;
  cursor:pointer;
  transition:.15s;
}
.btn-primary{ background:var(--accent); color:var(--ink); }
.btn-primary:hover{ background:var(--accent-dark); }
.btn-outline{ border-color:var(--steel-light); color:var(--white); }
.btn-outline:hover{ border-color:var(--white); }
.btn-dark{ background:var(--ink); color:var(--white); }
.btn-dark:hover{ background:var(--ink-2); }

/* =========================================================
   SECTIONS
   ========================================================= */
section{ padding:70px 0; }
.section-head{
  display:flex;
  justify-content:space-between;
  align-items:flex-end;
  gap:20px;
  margin-bottom:36px;
  flex-wrap:wrap;
}
.section-head h2{ font-size:clamp(1.5rem,3vw,2.1rem); margin:0; }
.section-head p{ color:var(--steel); margin:0; max-width:46ch; }

.about-intro-grid{
  display:grid;
  grid-template-columns:minmax(0, 1.2fr) minmax(260px, 0.8fr);
  gap:32px;
  align-items:center;
}
.about-intro-copy h1{
  max-width:50ch;
  font-size:clamp(1.8rem,3.5vw,2.6rem);
  margin-bottom:16px;
}
.about-intro-copy p{
  max-width:70ch;
  font-size:1.05rem;
  color:var(--ink-2);
}
.about-intro-media{
  display:flex;
  justify-content:center;
}
.about-logo-card{
  width:min(100%, 340px);
  padding:24px;
  background:linear-gradient(135deg, var(--paper) 0%, var(--white) 100%);
  border:1px solid var(--line);
  border-radius:var(--radius);
  box-shadow:0 12px 30px rgba(27,36,48,.08);
}
.about-logo-card img{
  width:100%;
  height:auto;
  object-fit:contain;
}

@media (max-width:900px){
  .about-intro-grid{ grid-template-columns:1fr; }
  .about-intro-media{ order:-1; }
  .about-logo-card{ max-width:320px; }
}

.bg-ink{ background:var(--ink); color:var(--white); }
.bg-ink h2{ color:var(--white); }
.bg-white{ background:var(--white); }

/* =========================================================
   CATEGORY / PRODUCT CARDS  — "spec sheet" (signature element)
   ========================================================= */
.grid{
  display:grid;
  gap:22px;
}
.grid-3{ grid-template-columns:repeat(3,1fr); }
.grid-4{ grid-template-columns:repeat(4,1fr); }
@media (max-width:980px){ .grid-3,.grid-4{ grid-template-columns:repeat(2,1fr); } }
@media (max-width:600px){ .grid-3,.grid-4{ grid-template-columns:1fr; } }

.spec-card{
  position:relative;
  background:var(--white);
  border:1px solid var(--line);
  transition:.2s;
}
.spec-card:hover{
  border-color:var(--ink);
  transform:translateY(-3px);
  box-shadow:0 10px 24px rgba(27,36,48,.12);
}
.spec-card .corner{
  position:absolute; width:14px; height:14px;
  border:2px solid var(--accent);
  opacity:0; transition:.2s;
}
.spec-card:hover .corner{ opacity:1; }
.corner.tl{ top:-1px; left:-1px; border-right:none; border-bottom:none; }
.corner.tr{ top:-1px; right:-1px; border-left:none; border-bottom:none; }
.corner.bl{ bottom:-1px; left:-1px; border-right:none; border-top:none; }
.corner.br{ bottom:-1px; right:-1px; border-left:none; border-top:none; }

.spec-card .thumb{
  aspect-ratio:4/3;
  overflow:hidden;
  background:var(--paper-2);
  border-bottom:1px solid var(--line);
}
.spec-card .thumb img{ width:100%; height:100%; object-fit:cover; }
.spec-card .body{ padding:18px 18px 20px; }
.spec-card .code{
  font-family:var(--font-mono);
  font-size:.72rem;
  color:var(--steel);
  letter-spacing:.06em;
  margin-bottom:6px;
  display:block;
}
.spec-card h3{
  font-size:1.05rem;
  margin-bottom:8px;
}
.spec-card p.desc{
  color:var(--ink-2);
  font-size:.9rem;
  margin-bottom:12px;
}
.spec-card .meta{
  display:flex;
  justify-content:space-between;
  align-items:center;
  border-top:1px dashed var(--line);
  padding-top:12px;
  font-family:var(--font-mono);
  font-size:.72rem;
  color:var(--steel-light);
  text-transform:uppercase;
}
.spec-card a.card-link{ position:absolute; inset:0; z-index:2; }

/* category chip */
.category-card{
  background:var(--ink);
  color:var(--white);
  padding:26px 22px;
  position:relative;
  overflow:hidden;
  border-bottom:3px solid var(--accent);
}
.category-card h3{ color:var(--white); font-size:1.05rem; margin-bottom:6px;}
.category-card p{ color:var(--steel-light); font-size:.85rem; margin-bottom:14px; }
.category-card .num{
  font-family:var(--font-mono);
  color:var(--accent);
  font-size:.75rem;
  letter-spacing:.1em;
}
.category-card a.card-link{ position:absolute; inset:0; }
.category-card:hover{ background:var(--ink-2); }

/* =========================================================
   FILTER BAR (trang sản phẩm)
   ========================================================= */
.filter-bar{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  margin-bottom:32px;
}
.filter-chip{
  font-family:var(--font-mono);
  font-size:.78rem;
  text-transform:uppercase;
  letter-spacing:.05em;
  padding:9px 16px;
  border:1px solid var(--line-dark);
  background:transparent;
  color:var(--ink);
  cursor:pointer;
  transition:.15s;
}
.filter-chip:hover{ border-color:var(--ink); }
.filter-chip.active{
  background:var(--ink);
  color:var(--accent);
  border-color:var(--ink);
}

/* =========================================================
   BREADCRUMB
   ========================================================= */
.breadcrumb{
  font-family:var(--font-mono);
  font-size:.75rem;
  color:var(--steel);
  text-transform:uppercase;
  letter-spacing:.05em;
  padding:18px 0;
  border-bottom:1px solid var(--line);
}
.breadcrumb a:hover{ color:var(--accent-dark); }
.breadcrumb .sep{ margin:0 8px; color:var(--line-dark); }

/* =========================================================
   PRODUCT DETAIL
   ========================================================= */
.detail-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:50px;
  align-items:flex-start;
}
.detail-gallery img{
  width:100%;
  border:1px solid var(--line);
  aspect-ratio:4/3;
  object-fit:cover;
}
.detail-info .code{
  font-family:var(--font-mono);
  color:var(--steel);
  font-size:.8rem;
  letter-spacing:.06em;
  display:block;
  margin-bottom:8px;
}
.detail-info h1{ font-size:clamp(1.6rem,3vw,2.2rem); }
.detail-description{ padding-top:0; }
.detail-description-card{
  background:var(--paper);
  border:1px solid var(--line);
  padding:28px 30px;
}
.detail-description-card h2{
  font-size:clamp(1.25rem,2.2vw,1.6rem);
  margin-bottom:12px;
}
.detail-description-card p{ color:var(--ink-2); }
.detail-bullets{
  display:grid;
  gap:8px;
  margin:16px 0 0;
  padding-left:18px;
  list-style:disc;
  color:var(--ink-2);
}
.spec-table{
  width:100%;
  border-collapse:collapse;
  margin:24px 0;
  font-family:var(--font-mono);
  font-size:.85rem;
}
.spec-table tr{ border-bottom:1px solid var(--line); }
.spec-table td{ padding:10px 4px; }
.spec-table td:first-child{ color:var(--steel); text-transform:uppercase; letter-spacing:.05em; width:40%; }
@media (max-width:820px){ .detail-grid{ grid-template-columns:1fr; gap:30px; } }

/* =========================================================
   POSTS
   ========================================================= */
.post-card{
  background:var(--white);
  border:1px solid var(--line);
  display:flex;
  flex-direction:column;
  position:relative;
}
.post-card .thumb{ aspect-ratio:16/10; overflow:hidden; }
.post-card .thumb img{ width:100%; height:100%; object-fit:cover; }
.post-card .body{ padding:18px; }
.post-card .date{
  font-family:var(--font-mono);
  font-size:.7rem;
  color:var(--steel);
  text-transform:uppercase;
  letter-spacing:.08em;
}
.post-card h3{ font-size:1.02rem; margin:8px 0; }
.post-card a.card-link{ position:absolute; inset:0; }

.post-article{ max-width:760px; margin:0 auto; }
.post-article .cover{ width:100%; aspect-ratio:16/9; object-fit:cover; margin-bottom:28px; border:1px solid var(--line); }
.post-article h1{ font-size:clamp(1.7rem,3.2vw,2.3rem); }
.post-article .meta{
  font-family:var(--font-mono);
  font-size:.78rem;
  color:var(--steel);
  text-transform:uppercase;
  margin-bottom:24px;
}
.post-article p{ font-size:1.02rem; color:var(--ink-2); }
.post-article h2{ font-size:1.3rem; margin-top:1.6em; }

/* =========================================================
   CTA STRIP
   ========================================================= */
.cta-strip{
  background:var(--accent);
  padding:46px 0;
}
.cta-strip .container{
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:20px;
  flex-wrap:wrap;
}
.cta-strip h2{ color:var(--ink); margin:0; font-size:1.5rem; }
.cta-strip p{ margin:4px 0 0; color:var(--ink-2); }

/* =========================================================
   CONTACT
   ========================================================= */
.contact-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:50px;
}
.contact-info .item{
  border-left:2px solid var(--accent);
  padding:6px 0 6px 16px;
  margin-bottom:22px;
}
.contact-info .label{
  font-family:var(--font-mono);
  font-size:.72rem;
  color:var(--steel);
  text-transform:uppercase;
  letter-spacing:.08em;
  display:block;
  margin-bottom:4px;
}
.contact-info .value{
  font-family:var(--font-display);
  font-size:1.05rem;
  color: var(--steel-light);
}
form.contact-form{ display:flex; flex-direction:column; gap:16px; }
.contact-form label{
  font-family:var(--font-mono);
  font-size:.72rem;
  text-transform:uppercase;
  letter-spacing:.06em;
  color:var(--steel);
  margin-bottom:6px;
  display:block;
}
.contact-form input,
.contact-form textarea{
  width:100%;
  padding:12px 14px;
  border:1px solid var(--line-dark);
  background:var(--white);
  font-family:var(--font-body);
  font-size:.95rem;
  border-radius:var(--radius);
}
.contact-form textarea{ min-height:120px; resize:vertical; }
@media (max-width:820px){ .contact-grid{ grid-template-columns:1fr; } }

/* =========================================================
   FOOTER
   ========================================================= */
.site-footer{
  background:var(--ink);
  color:var(--steel-light);
  padding:56px 0 24px;
  margin-top:60px;
}
.footer-grid{
  display:grid;
  grid-template-columns:1.4fr 1fr 1fr 1.2fr;
  gap:30px;
  padding-bottom:36px;
  border-bottom:1px solid var(--line-dark);
}
.footer-grid h4{ color:var(--white); font-size:.9rem; margin-bottom:14px; }
.footer-grid li{ margin-bottom:8px; font-size:.9rem; }
.footer-grid a:hover{ color:var(--accent); }
.footer-brand p{ max-width:34ch; font-size:.88rem; }
.footer-bottom{
  display:flex;
  justify-content:space-between;
  flex-wrap:wrap;
  gap:10px;
  padding-top:20px;
  font-family:var(--font-mono);
  font-size:.72rem;
  text-transform:uppercase;
  letter-spacing:.05em;
}
.placeholder-fill{
  color: var(--accent);
  border-bottom:1px dashed var(--accent);
}
@media (max-width:880px){
  .footer-grid{ grid-template-columns:1fr 1fr; }
}
@media (max-width:520px){
  .footer-grid{ grid-template-columns:1fr; }
}

/* =========================================================
   EMPTY STATE / LOADING
   ========================================================= */
.empty-state, .loading-state{
  text-align:center;
  padding:60px 20px;
  color:var(--steel);
  font-family:var(--font-mono);
  font-size:.9rem;
  text-transform:uppercase;
  letter-spacing:.05em;
  grid-column:1/-1;
}