/* ==========================================================================
   SIL-VEX ENGINEERING — base.css
   Shared on every page: design tokens, reset, typography, nav, footer,
   buttons and reusable components. Page-specific layout lives in its own
   file (home.css, products.css, ...).

   DESIGN LANGUAGE — "Precision engineering / technical blueprint"
   Deep ink navy + graphite surfaces, engineering-red accents, blueprint
   grids, dimension-line details, Oswald display type over IBM Plex body.
   ========================================================================== */

:root{
  /* ---- palette -------------------------------------------------------- */
  --ink:        #0B1620;   /* headings / high-contrast text            */
  --ink-2:      #12222E;   /* deep panel surface                       */
  --steel:      #44576A;   /* body copy                                 */
  --steel-soft: #7C8B96;   /* muted copy, captions                      */
  --navy:       #0B3B5C;   /* primary brand blue                        */
  --navy-2:     #0E4A72;
  --navy-deep:  #061C2C;   /* darkest blue, footers, hero bg            */
  --navy-deep-2:#04131F;
  --red:        #C3311F;   /* brand red accent                          */
  --red-2:      #E23A25;   /* bright red for gradients                  */
  --red-deep:   #8C2013;
  --silver:     #B9C2C9;   /* metallic dividers / strokes               */
  --line:       #D9DEE2;
  --bg:         #F2F4F6;
  --bg-alt:     #E8ECEF;
  --paper:      #FFFFFF;
  --wa:         #25D366;

  --shadow-sm:  0 6px 18px -8px rgba(6,28,44,.18);
  --shadow:     0 22px 50px -24px rgba(6,28,44,.38);
  --shadow-lg:  0 34px 70px -30px rgba(6,28,44,.5);

  /* ---- type ------------------------------------------------------------ */
  --font-display: 'Oswald', sans-serif;
  --font-body:    'IBM Plex Sans', sans-serif;
  --font-mono:    'IBM Plex Mono', monospace;

  /* ---- layout ------------------------------------------------------------ */
  --maxw: 1200px;
  --pad: clamp(20px, 5vw, 64px);
  --radius: 4px;
  --radius-lg: 10px;

  --header-h: 68px;
}

*, *::before, *::after{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }
body{
  margin:0;
  font-family: var(--font-body);
  color: var(--steel);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  line-height: 1.65;
  overflow-x: hidden;
}
::selection{ background: var(--red); color:#fff; }

/* custom scrollbar */
::-webkit-scrollbar{ width: 11px; }
::-webkit-scrollbar-track{ background: var(--navy-deep-2); }
::-webkit-scrollbar-thumb{
  background: linear-gradient(180deg, var(--navy-2), var(--navy));
  border-radius: 8px;
  border: 2px solid var(--navy-deep-2);
}
::-webkit-scrollbar-thumb:hover{ background: var(--red); }

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);
  color: var(--ink);
  text-transform: uppercase;
  letter-spacing: .01em;
  line-height: 1.1;
  margin: 0 0 .45em;
  font-weight: 600;
}
p{ margin:0 0 1em; }
.mono{ font-family: var(--font-mono); }

:focus-visible{
  outline: 2px solid var(--red);
  outline-offset: 3px;
}

.wrap{
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--pad);
}

section{ padding: clamp(64px, 9vw, 112px) 0; }

/* ------------------------------------------------------------ scrollbar-progress */
.scroll-progress{
  position: fixed; top:0; left:0; right:0; height:3px; z-index: 200;
  background: rgba(255,255,255,.06);
  pointer-events: none;
}
.scroll-progress span{
  display:block; height:100%; width:0%;
  background: linear-gradient(90deg, var(--red-2), var(--red));
  box-shadow: 0 0 12px rgba(226,58,37,.6);
}

/* ------------------------------------------------------------ section head */
.section-head{ margin-bottom: clamp(30px, 4.5vw, 54px); }
.section-head .lead{
  font-size: clamp(1.55rem, 3.2vw, 2.35rem);
  max-width: 22ch;
  margin: .35em 0 .5em;
}
.section-head .sub{ max-width: 58ch; color: var(--steel-soft); margin:0; }
.section-head.on-dark .lead{ color:#fff; }
.section-head.on-dark .sub{ color: rgba(255,255,255,.6); }

.num{
  display:inline-flex; align-items:center; gap:10px;
  font-family: var(--font-mono); font-size:.7rem;
  letter-spacing:.22em; text-transform:uppercase;
  color: var(--red);
}
.num::after{
  content:""; width: 44px; height: 1px;
  background: linear-gradient(90deg, var(--red), transparent);
}
.num.on-dark{ color: var(--red-2); }

/* ------------------------------------------------------------ eyebrow */
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:.6em;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--red);
}
.eyebrow::before{
  content:"";
  width: 26px; height: 2px;
  background: var(--red);
}
.eyebrow.on-dark{ color: var(--red-2); }
.eyebrow.on-dark::before{ background: var(--red-2); }

/* ------------------------------------------------------------ buttons */
.btn{
  display:inline-flex;
  align-items:center;
  gap:.65em;
  padding: .95em 1.7em;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor:pointer;
  position:relative;
  overflow:hidden;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease, color .18s ease, border-color .18s ease;
}
.btn:hover{ transform: translateY(-3px); }
.btn:active{ transform: translateY(-1px); }

.btn .arr{ transition: transform .2s ease; display:inline-block; }
.btn:hover .arr{ transform: translateX(4px); }

.btn-primary{
  background: linear-gradient(135deg, var(--red-2), var(--red) 55%, var(--red-deep));
  color:#fff;
  box-shadow: 0 12px 26px -14px rgba(195,49,31,.65);
}
.btn-primary:hover{ box-shadow: 0 18px 34px -14px rgba(195,49,31,.8); }

.btn-outline{ border-color: rgba(255,255,255,.45); color:#fff; backdrop-filter: blur(4px); }
.btn-outline:hover{ background: rgba(255,255,255,.12); border-color:#fff; }

.btn-ghost{ border-color: var(--navy); color: var(--navy); background: transparent; }
.btn-ghost:hover{ background: var(--navy); color:#fff; }

.btn-ghost-dark{
  display:inline-flex; align-items:center; gap:.65em;
  padding: .95em 1.7em;
  font-family: var(--font-mono); font-size:.78rem; letter-spacing:.1em; text-transform:uppercase;
  border-radius: var(--radius); border: 1px solid var(--line);
  color: var(--ink); cursor:pointer; background: var(--paper);
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}
.btn-ghost-dark:hover{ transform: translateY(-3px); border-color: var(--navy); box-shadow: var(--shadow-sm); }

/* arrow text link */
.arrow-link{
  display:inline-flex; align-items:center; gap:.5em;
  font-family: var(--font-mono); font-size:.74rem; letter-spacing:.12em; text-transform:uppercase;
  color: var(--red); font-weight:500;
}
.arrow-link .arr{ transition: transform .2s ease; }
.arrow-link:hover .arr{ transform: translateX(5px); }

/* ---------------------------------------------------------------- nav -- */
.site-header{
  position: fixed; top:0; left:0; right:0; z-index: 100;
  background: rgba(4,19,31,.55);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(255,255,255,.08);
  transition: background .3s ease, box-shadow .3s ease;
}
.site-header.scrolled{
  background: rgba(4,19,31,.92);
  box-shadow: 0 14px 34px -18px rgba(0,0,0,.55);
}
.nav{
  display:flex; align-items:center; justify-content:space-between;
  height: var(--header-h);
  transition: height .3s ease;
}
.site-header.scrolled .nav{ height: 58px; }
.logo{ display:flex; align-items:center; gap:12px; }
.logo-mark{
  width: 36px; height:36px; position:relative; flex:none;
  background: linear-gradient(135deg, var(--red-2) 0 42%, var(--ink) 42% 100%);
  clip-path: polygon(30% 0, 100% 0, 70% 100%, 0 100%);
  box-shadow: 0 6px 14px -6px rgba(226,58,37,.6);
}
.logo-text{ line-height:1.1; }
.logo-text b{
  display:block; font-family: var(--font-display);
  color:#fff; letter-spacing:.06em; font-size:1.18rem;
}
.logo-text span{
  display:block; font-family: var(--font-mono); font-size:.56rem;
  letter-spacing:.34em; color: var(--silver);
}
.nav-links{ display:flex; align-items:center; gap: 34px; }
.nav-links a{
  font-family: var(--font-mono);
  font-size:.74rem; letter-spacing:.1em; text-transform:uppercase;
  color: rgba(255,255,255,.72);
  position:relative; padding-block:6px;
}
.nav-links a::after{
  content:""; position:absolute; left:0; right:100%; bottom:0; height:2px;
  background: linear-gradient(90deg, var(--red-2), var(--red));
  transition: right .25s ease;
}
.nav-links a:hover{ color:#fff; }
.nav-links a:hover::after,
.nav-links a.active::after{ right:0; }
.nav-links a.active{ color:#fff; }
.nav-cta{ display:flex; align-items:center; gap:18px; }
.nav-toggle{
  display:none; flex-direction:column; gap:5px; background:none; border:0; cursor:pointer; padding:6px;
}
.nav-toggle span{ width:22px; height:2px; background:#fff; transition: transform .25s ease, opacity .25s ease; }
.nav-toggle[aria-expanded="true"] span:nth-child(1){ transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2){ opacity:0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3){ transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 980px){
  .nav-links{
    position:fixed; inset: var(--header-h) 0 auto 0; flex-direction:column; align-items:flex-start;
    background: rgba(4,19,31,.98);
    backdrop-filter: blur(14px);
    padding: 26px var(--pad) 34px;
    gap: 20px; transform: translateY(-10px); opacity:0; pointer-events:none;
    transition: opacity .25s ease, transform .25s ease;
    border-bottom: 1px solid rgba(255,255,255,.1);
    box-shadow: 0 30px 50px -20px rgba(0,0,0,.6);
  }
  .nav-links.open{ opacity:1; transform:none; pointer-events:auto; }
  .nav-links a{ font-size:.95rem; }
  .nav-toggle{ display:flex; }
  .nav-cta .btn-outline{ display:none; }
}

/* ------------------------------------------------------------ footer -- */
.site-footer{
  background: var(--navy-deep-2);
  color: rgba(255,255,255,.66);
  padding-block: 64px 26px;
  position:relative;
}
.site-footer::before{
  content:""; position:absolute; top:0; left:0; right:0; height:3px;
  background: linear-gradient(90deg, var(--red-2), var(--red), transparent 70%);
}
.footer-grid{
  display:grid;
  grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
  gap: 42px;
  padding-bottom: 44px;
  border-bottom: 1px solid rgba(255,255,255,.1);
}
.footer-grid h4{
  color:#fff; font-size:.8rem; letter-spacing:.18em; margin-bottom:1.1em;
  position:relative; padding-bottom:.6em;
}
.footer-grid h4::after{
  content:""; position:absolute; left:0; bottom:0; width:22px; height:2px; background: var(--red);
}
.footer-grid p, .footer-grid li{ font-size:.9rem; line-height:1.7; }
.footer-grid a{ transition: color .15s ease, padding-left .15s ease; }
.footer-grid a:hover{ color:#fff; }
.footer-grid li + li{ margin-top:.6em; }
.footer-grid .f-email{ display:inline-flex; align-items:center; gap:.5em; }
.footer-grid .f-email::before{ content:"→"; color: var(--red-2); font-family: var(--font-mono); }
.footer-grid .f-tel::before{ content:"☎"; color: var(--red-2); margin-right:.5em; }
.footer-bottom{
  display:flex; justify-content:space-between; flex-wrap:wrap; gap:10px;
  padding-top: 24px; font-family: var(--font-mono); font-size:.7rem;
  letter-spacing:.06em; color: rgba(255,255,255,.38);
}
@media (max-width: 820px){
  .footer-grid{ grid-template-columns: 1fr 1fr; }
}
@media (max-width: 520px){
  .footer-grid{ grid-template-columns: 1fr; }
}

/* ------------------------------------------------------- spec / rows -- */
.spec-row{
  display:grid;
  grid-template-columns: 170px 1fr;
  gap: 26px;
  padding: 26px 0;
  border-top: 1px solid var(--line);
  transition: background .2s ease, padding-left .2s ease;
}
.spec-row:hover{ background: rgba(11,59,92,.03); padding-left: 12px; }
.spec-row:last-child{ border-bottom: 1px solid var(--line); }
.spec-row .spec-label{
  font-family: var(--font-mono);
  font-size:.7rem; letter-spacing:.16em; text-transform:uppercase;
  color: var(--red);
}
.spec-row h3{ font-size:1.15rem; margin-bottom:.3em; }
@media (max-width:640px){
  .spec-row{ grid-template-columns: 1fr; gap:8px; }
}

/* ------------------------------------------------------------- chips -- */
.chip{
  display:inline-block;
  padding:.35em .95em;
  border:1px solid var(--line);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size:.68rem;
  letter-spacing:.05em;
  color: var(--steel);
  background: var(--paper);
  transition: border-color .15s ease, color .15s ease;
}
.chip:hover{ border-color: var(--navy); color: var(--navy); }

/* --------------------------------------------------------- reveal-on-scroll */
.reveal{
  opacity:0; transform: translateY(28px);
  transition: opacity .8s cubic-bezier(.2,.6,.2,1), transform .8s cubic-bezier(.2,.6,.2,1);
}
.reveal.is-visible{ opacity:1; transform:none; }
.reveal-l{
  opacity:0; transform: translateX(-34px);
  transition: opacity .8s cubic-bezier(.2,.6,.2,1), transform .8s cubic-bezier(.2,.6,.2,1);
}
.reveal-l.is-visible{ opacity:1; transform:none; }
.reveal-r{
  opacity:0; transform: translateX(34px);
  transition: opacity .8s cubic-bezier(.2,.6,.2,1), transform .8s cubic-bezier(.2,.6,.2,1);
}
.reveal-r.is-visible{ opacity:1; transform:none; }
.reveal-scale{
  opacity:0; transform: scale(.94);
  transition: opacity .8s cubic-bezier(.2,.6,.2,1), transform .8s cubic-bezier(.2,.6,.2,1);
}
.reveal-scale.is-visible{ opacity:1; transform:none; }

@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior:auto; }
  .reveal, .reveal-l, .reveal-r, .reveal-scale{ opacity:1; transform:none; transition:none; }
  .scroll-progress span{ transition:none; }
}

/* ------------------------------------------------------ page banner --- */
.page-banner{
  background:
    radial-gradient(52% 70% at 85% 10%, rgba(14,74,114,.5), transparent 70%),
    radial-gradient(40% 60% at 5% 90%, rgba(195,49,31,.18), transparent 70%),
    var(--navy-deep);
  color:#fff;
  padding: calc(var(--header-h) + 64px) 0 58px;
  position:relative;
  overflow:hidden;
}
.page-banner::before{
  content:"";
  position:absolute; inset:0;
  background-image:
    linear-gradient(rgba(255,255,255,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.05) 1px, transparent 1px);
  background-size: 44px 44px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,.85), transparent);
          mask-image: linear-gradient(180deg, rgba(0,0,0,.85), transparent);
}
.page-banner::after{
  content:""; position:absolute; left:0; right:0; bottom:0; height:2px;
  background: linear-gradient(90deg, var(--red-2), transparent 60%);
}
.page-banner h1{ color:#fff; position:relative; font-size: clamp(2.1rem, 5vw, 3.3rem); max-width: 20ch; }
.page-banner p{ position:relative; max-width:660px; color: rgba(255,255,255,.72); font-size:1.02rem; }
.page-banner .crumb{
  position:relative; display:inline-flex; align-items:center; gap:.6em;
  font-family: var(--font-mono); font-size:.68rem; letter-spacing:.2em; text-transform:uppercase;
  color: rgba(255,255,255,.45); margin-bottom: 18px;
}
.page-banner .crumb b{ color: var(--red-2); font-weight:500; }

/* ------------------------------------------------------- cta banner --- */
.cta-banner{
  background:
    radial-gradient(60% 120% at 15% 0%, rgba(14,74,114,.55), transparent 70%),
    linear-gradient(135deg, var(--navy-deep) 0%, var(--navy) 100%);
  color:#fff;
  position:relative; overflow:hidden;
}
.cta-banner::before{
  content:""; position:absolute; inset:0;
  background-image:
    linear-gradient(rgba(255,255,255,.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.04) 1px, transparent 1px);
  background-size: 40px 40px;
}
.cta-inner{
  position:relative;
  display:flex; align-items:center; justify-content:space-between; gap:30px; flex-wrap:wrap;
}
.cta-inner h2{ color:#fff; font-size: clamp(1.6rem, 3vw, 2.2rem); margin-bottom:.25em; max-width: 18ch; }
.cta-inner p{ color: rgba(255,255,255,.72); max-width: 48ch; margin:0; }

/* ------------------------------------------------- back-to-top + WA --- */
.back-to-top{
  position: fixed; right: 22px; bottom: 92px; z-index: 90;
  width: 44px; height: 44px; border-radius: 50%;
  border: 1px solid rgba(255,255,255,.2);
  background: rgba(11,23,32,.92);
  color:#fff; cursor:pointer;
  font-size: 1rem; line-height:1;
  opacity:0; transform: translateY(12px); pointer-events:none;
  transition: opacity .25s ease, transform .25s ease, background .2s ease;
  display:flex; align-items:center; justify-content:center;
  box-shadow: var(--shadow-sm);
}
.back-to-top.show{ opacity:1; transform:none; pointer-events:auto; }
.back-to-top:hover{ background: var(--red); }

.wa-float{
  position: fixed; right: 20px; bottom: 24px; z-index: 90;
  width: 56px; height: 56px; border-radius: 50%;
  background: var(--wa); color:#fff;
  display:flex; align-items:center; justify-content:center;
  box-shadow: 0 14px 30px -10px rgba(37,211,102,.65);
  transition: transform .2s ease, box-shadow .2s ease;
}
.wa-float:hover{ transform: translateY(-4px) scale(1.05); box-shadow: 0 18px 36px -10px rgba(37,211,102,.8); }
.wa-float svg{ width: 28px; height: 28px; fill: currentColor; }
.wa-float::before{
  content:""; position:absolute; inset:0; border-radius:50%;
  border: 2px solid var(--wa);
  animation: pulseRing 2.2s ease-out infinite;
}
.wa-float:hover::before{ animation: none; }

/* ------------------------------------------------------ grid pattern -- */
.grid-pattern{
  background-image:
    linear-gradient(rgba(11,59,92,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(11,59,92,.05) 1px, transparent 1px);
  background-size: 40px 40px;
}