/* ============================================================================
   StoneBridge Systems — brand site styles
   Dark · structural · premium.  Palette: near-black + steel-navy + stone + copper.
   Self-hosted fonts. Accessible (WCAG-minded). Reduced-motion safe.
   ========================================================================== */

/* ---- self-hosted fonts ---------------------------------------------------- */
@font-face{font-family:"Space Grotesk";src:url("../fonts/space-grotesk-400.woff2") format("woff2");font-weight:400;font-display:swap}
@font-face{font-family:"Space Grotesk";src:url("../fonts/space-grotesk-500.woff2") format("woff2");font-weight:500;font-display:swap}
@font-face{font-family:"Space Grotesk";src:url("../fonts/space-grotesk-700.woff2") format("woff2");font-weight:700;font-display:swap}
@font-face{font-family:"Inter";src:url("../fonts/inter-400.woff2") format("woff2");font-weight:400;font-display:swap}
@font-face{font-family:"Inter";src:url("../fonts/inter-500.woff2") format("woff2");font-weight:500;font-display:swap}
@font-face{font-family:"Inter";src:url("../fonts/inter-600.woff2") format("woff2");font-weight:600;font-display:swap}
@font-face{font-family:"Inter";src:url("../fonts/inter-700.woff2") format("woff2");font-weight:700;font-display:swap}

/* ---- design tokens -------------------------------------------------------- */
:root{
  --bg:#0b0f16;            /* near-black canvas */
  --bg-elev:#111827;       /* elevated panels/cards */
  --bg-elev-2:#0e1420;
  --navy:#13243b;          /* steel navy */
  --navy-deep:#0c1826;
  --line:rgba(200,214,233,.10);
  --line-strong:rgba(200,214,233,.17);
  --ink:#eaf1f8;           /* headings */
  --text:#c2cedd;          /* body */
  --muted:#8f9fb2;         /* muted labels (AA on --bg) */
  --copper:#c8823c;        /* accent (fills) */
  --copper-bright:#e6ad6e; /* accent text / hover / highlights */
  --copper-soft:rgba(200,130,60,.14);
  --copper-glow:rgba(230,173,110,.35);
  --ff-display:"Space Grotesk",system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
  --ff-body:"Inter",system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  --r:14px;               /* card radius */
  --r-sm:10px;
  --maxw:1140px;
  --gut:clamp(20px,5vw,40px);
  --sp-section:clamp(64px,9vw,116px);
  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---- reset / base --------------------------------------------------------- */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;background:var(--bg);color:var(--text);
  font-family:var(--ff-body);font-size:1.0625rem;line-height:1.65;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
  overflow-x:hidden;
}
img,svg{display:block;max-width:100%}
a{color:var(--copper-bright);text-decoration:none}
a:hover{text-decoration:underline;text-underline-offset:3px}
h1,h2,h3{font-family:var(--ff-display);color:var(--ink);line-height:1.1;font-weight:700;margin:0 0 .5em;letter-spacing:-.01em}
h1{font-size:clamp(2.3rem,6vw,3.7rem);letter-spacing:-.02em}
h2{font-size:clamp(1.7rem,3.6vw,2.5rem)}
h3{font-size:1.2rem;font-weight:600}
p{margin:0 0 1rem}
::selection{background:var(--copper);color:#0b0f16}

/* ---- accessibility helpers ----------------------------------------------- */
.skip{position:absolute;left:-9999px;top:0;z-index:200;background:var(--copper);color:#0b0f16;
  padding:10px 16px;border-radius:0 0 8px 0;font-weight:600}
.skip:focus{left:0}
:focus-visible{outline:2.5px solid var(--copper-bright);outline-offset:3px;border-radius:4px}
.visually-hidden{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;
  clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* ---- layout --------------------------------------------------------------- */
.container{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--gut)}
.section{padding-block:var(--sp-section);position:relative}
.eyebrow{display:inline-flex;align-items:center;gap:9px;font-family:var(--ff-display);font-weight:500;
  font-size:.78rem;letter-spacing:.18em;text-transform:uppercase;color:var(--copper-bright);margin-bottom:16px}
.eyebrow::before{content:"";width:22px;height:2px;background:var(--copper);border-radius:2px;display:inline-block}
.section-head{max-width:640px;margin-bottom:clamp(34px,5vw,52px)}
.section-head p{color:var(--muted);font-size:1.1rem;margin:0}
.lead{font-size:1.18rem;color:var(--text)}

/* ---- buttons -------------------------------------------------------------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;
  font-family:var(--ff-display);font-weight:600;font-size:.98rem;letter-spacing:.005em;
  padding:14px 24px;border-radius:11px;border:1px solid transparent;cursor:pointer;
  transition:transform .16s var(--ease),background .16s,border-color .16s,box-shadow .16s;white-space:nowrap}
.btn:hover{text-decoration:none;transform:translateY(-2px)}
.btn:active{transform:translateY(0)}
.btn-primary{background:var(--copper);color:#0b0f16;box-shadow:0 8px 26px -12px var(--copper-glow)}
.btn-primary:hover{background:var(--copper-bright);box-shadow:0 12px 34px -12px var(--copper-glow)}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--line-strong)}
.btn-ghost:hover{border-color:var(--copper);color:var(--copper-bright)}
.btn[disabled]{opacity:.6;cursor:not-allowed;transform:none}
.btn svg{width:18px;height:18px}

/* ---- brand lockup --------------------------------------------------------- */
.brand{display:inline-flex;align-items:center;gap:12px;color:var(--ink)}
.brand:hover{text-decoration:none}
.brand .emblem{width:34px;height:auto;color:var(--ink);flex:0 0 auto;transition:color .2s}
.brand:hover .emblem{color:var(--copper-bright)}
.brand-name{display:flex;flex-direction:column;line-height:1}
.brand-name b{font-family:var(--ff-display);font-weight:700;font-size:1.02rem;letter-spacing:.06em;color:var(--ink);text-transform:uppercase}
.brand-name span{font-size:.62rem;letter-spacing:.22em;text-transform:uppercase;color:var(--muted);margin-top:3px}

/* ---- header / nav --------------------------------------------------------- */
.site-header{position:sticky;top:0;z-index:100;background:rgba(11,15,22,.72);
  backdrop-filter:saturate(160%) blur(12px);border-bottom:1px solid transparent;transition:border-color .25s,background .25s}
.site-header.is-scrolled{border-bottom-color:var(--line);background:rgba(11,15,22,.9)}
.nav{display:flex;align-items:center;justify-content:space-between;gap:20px;height:70px}
.nav-links{display:flex;align-items:center;gap:30px;margin:0;padding:0;list-style:none}
.nav-links a{color:var(--text);font-size:.96rem;font-weight:500}
.nav-links a:hover{color:var(--ink);text-decoration:none}
.nav-cta{display:flex;align-items:center;gap:14px}
.nav-menu{display:flex;align-items:center;gap:30px}
.nav-menu>.btn-primary{display:none}          /* desktop CTA lives in .nav-cta; this button is mobile-menu only */
.nav-toggle{display:none;background:none;border:1px solid var(--line-strong);border-radius:9px;
  width:44px;height:44px;color:var(--ink);cursor:pointer;align-items:center;justify-content:center}
.nav-toggle svg{width:22px;height:22px}
.nav-toggle .icon-close{display:none}
.nav-toggle[aria-expanded="true"] .icon-open{display:none}
.nav-toggle[aria-expanded="true"] .icon-close{display:block}

/* ---- signature: scroll span-line ----------------------------------------- */
/* top progress bar (all viewports) */
.span-top{position:fixed;top:0;left:0;height:3px;width:100%;z-index:120;pointer-events:none}
.span-top span{display:block;height:100%;width:var(--progress,0%);
  background:linear-gradient(90deg,var(--copper),var(--copper-bright));box-shadow:0 0 14px var(--copper-glow)}
/* left vertical rail — the "bridge" drawing itself (desktop only) */
.span-rail{position:fixed;left:26px;top:130px;bottom:130px;width:2px;z-index:90;pointer-events:none;display:none}
.span-rail .track{position:absolute;inset:0;background:var(--line-strong)}
.span-rail .fill{position:absolute;left:0;top:0;width:100%;height:var(--progress,0%);
  background:linear-gradient(180deg,var(--copper),var(--copper-bright))}
.span-rail .cap{position:absolute;left:50%;top:var(--progress,0%);width:9px;height:9px;border-radius:50%;
  transform:translate(-50%,-50%);background:var(--copper-bright);box-shadow:0 0 12px 2px var(--copper-glow)}
@media(min-width:1180px){.span-rail{display:block}}

/* ---- reveal-on-scroll ----------------------------------------------------- */
.reveal{opacity:0;transform:translateY(20px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.reveal.in{opacity:1;transform:none}
.reveal.d1{transition-delay:.08s}.reveal.d2{transition-delay:.16s}.reveal.d3{transition-delay:.24s}

/* ---- hero ----------------------------------------------------------------- */
.hero{position:relative;overflow:hidden;padding-block:clamp(72px,12vw,140px) clamp(60px,8vw,96px);
  background:radial-gradient(120% 90% at 78% -10%,var(--navy) 0%,var(--navy-deep) 42%,var(--bg) 78%)}
.hero-blueprint{position:absolute;inset:0;z-index:0;pointer-events:none;overflow:hidden}
/* faint engineering grid */
.hero-blueprint .grid{position:absolute;inset:-2px;
  background-image:linear-gradient(var(--line) 1px,transparent 1px),linear-gradient(90deg,var(--line) 1px,transparent 1px);
  background-size:44px 44px;mask-image:radial-gradient(120% 85% at 70% 8%,#000 0%,transparent 72%);
  -webkit-mask-image:radial-gradient(120% 85% at 70% 8%,#000 0%,transparent 72%);
  will-change:transform}
.hero-blueprint .glow{position:absolute;right:-8%;top:-18%;width:min(620px,70vw);aspect-ratio:1;
  background:radial-gradient(circle,var(--copper-soft),transparent 62%)}
.hero-blueprint .watermark{position:absolute;right:2%;top:50%;transform:translateY(-50%);
  width:min(560px,54vw);color:var(--ink);opacity:.045;will-change:transform}
.hero-inner{position:relative;z-index:1;max-width:760px}
.hero h1{margin-bottom:.42em}
.hero .accent{color:var(--copper-bright)}
.hero-sub{font-size:clamp(1.08rem,2.1vw,1.32rem);color:var(--text);max-width:620px;margin-bottom:34px}
.hero-actions{display:flex;flex-wrap:wrap;gap:14px}
.hero-badge{display:inline-flex;align-items:center;gap:10px;margin-bottom:26px;padding:7px 14px 7px 10px;
  border:1px solid var(--line-strong);border-radius:999px;background:rgba(255,255,255,.02);
  font-size:.82rem;color:var(--muted);font-weight:500}
.hero-badge .dot{width:7px;height:7px;border-radius:50%;background:var(--copper);box-shadow:0 0 8px var(--copper-glow)}
.hero-badge b{color:var(--text);font-weight:600}

/* ---- positioning strip ---------------------------------------------------- */
.strip{border-block:1px solid var(--line);background:var(--bg-elev-2)}
.strip .container{padding-block:30px}
.strip p{font-family:var(--ff-display);font-weight:500;font-size:clamp(1.1rem,2.4vw,1.5rem);
  color:var(--ink);margin:0;max-width:900px;line-height:1.35}
.strip p .accent{color:var(--copper-bright)}

/* ---- services ------------------------------------------------------------- */
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.card{position:relative;background:linear-gradient(180deg,var(--bg-elev),var(--bg-elev-2));
  border:1px solid var(--line);border-radius:var(--r);padding:30px 28px;overflow:hidden;
  transition:border-color .25s,transform .25s var(--ease),box-shadow .25s}
.card::before{content:"";position:absolute;left:0;top:0;height:3px;width:100%;
  background:linear-gradient(90deg,var(--copper),transparent);opacity:0;transition:opacity .25s}
.card:hover{transform:translateY(-4px);border-color:var(--line-strong);box-shadow:0 22px 46px -30px rgba(0,0,0,.8)}
.card:hover::before{opacity:1}
.card .ic{width:52px;height:52px;border-radius:12px;display:flex;align-items:center;justify-content:center;
  background:var(--copper-soft);color:var(--copper-bright);margin-bottom:20px}
.card .ic svg{width:26px;height:26px}
.card .num{position:absolute;right:22px;top:20px;font-family:var(--ff-display);font-weight:700;
  font-size:1rem;color:rgba(200,214,233,.32)}
.card h3{color:var(--ink);font-size:1.24rem;margin-bottom:10px}
.card p{color:var(--muted);font-size:.98rem;margin:0}
.card .tag{display:inline-block;margin-top:16px;font-size:.82rem;color:var(--copper-bright);
  font-weight:500;font-family:var(--ff-display);letter-spacing:.01em}

/* ---- why / credibility ---------------------------------------------------- */
.why{background:
  linear-gradient(180deg,transparent,rgba(19,36,59,.35),transparent),var(--bg)}
.why-grid{display:grid;grid-template-columns:1fr 1fr;gap:clamp(34px,6vw,72px);align-items:center}
.why-copy .lead{margin-bottom:18px}
.why-copy p{color:var(--muted)}
.stats{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.stat{background:var(--bg-elev);border:1px solid var(--line);border-radius:var(--r);padding:24px 22px}
.stat b{display:block;font-family:var(--ff-display);font-weight:700;font-size:1.05rem;color:var(--copper-bright);
  margin-bottom:6px;letter-spacing:.01em}
.stat span{font-size:.94rem;color:var(--muted);line-height:1.5}
.contrast{margin-top:26px;border:1px solid var(--line);border-radius:var(--r);overflow:hidden}
.contrast div{display:flex;gap:12px;padding:14px 18px;font-size:.95rem;align-items:flex-start}
.contrast div+div{border-top:1px solid var(--line)}
.contrast .them{color:var(--muted);background:var(--bg-elev-2)}
.contrast .us{color:var(--text);background:rgba(200,130,60,.05)}
.contrast .k{flex:0 0 96px;font-family:var(--ff-display);font-weight:500;font-size:.8rem;
  letter-spacing:.03em;text-transform:uppercase;color:var(--copper-bright);padding-top:2px}
.contrast .them .k{color:var(--muted)}

/* ---- approach ------------------------------------------------------------- */
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;counter-reset:step}
.step{position:relative;padding:28px 26px;border:1px solid var(--line);border-radius:var(--r);
  background:var(--bg-elev-2)}
.step .n{counter-increment:step;font-family:var(--ff-display);font-weight:700;font-size:.85rem;
  color:#0b0f16;background:var(--copper);width:34px;height:34px;border-radius:9px;display:flex;
  align-items:center;justify-content:center;margin-bottom:16px}
.step .n::before{content:"0" counter(step)}
.step h3{font-size:1.12rem;margin-bottom:8px}
.step p{color:var(--muted);font-size:.96rem;margin:0}

/* ---- contact -------------------------------------------------------------- */
.contact{background:radial-gradient(120% 100% at 20% 0%,var(--navy-deep),var(--bg) 60%)}
.contact-grid{display:grid;grid-template-columns:.85fr 1.15fr;gap:clamp(34px,6vw,64px);align-items:start}
.contact-copy h2{margin-bottom:14px}
.contact-copy p{color:var(--muted)}
.contact-copy .lead{color:var(--text)}
.next{list-style:none;margin:24px 0 0;padding:0;display:grid;gap:14px}
.next li{display:flex;gap:12px;align-items:flex-start;color:var(--text);font-size:.98rem}
.next li svg{width:20px;height:20px;color:var(--copper-bright);flex:0 0 auto;margin-top:3px}
.contact-direct{margin-top:26px;font-size:.95rem;color:var(--muted)}
.contact-direct a{font-weight:600}

.form{background:var(--bg-elev);border:1px solid var(--line);border-radius:var(--r);
  padding:clamp(24px,3vw,34px)}
.field{margin-bottom:18px}
.grid2{display:grid;grid-template-columns:1fr 1fr;column-gap:16px}
.grid2 .field{margin-bottom:18px}
.field label{display:block;font-family:var(--ff-display);font-weight:500;font-size:.85rem;
  letter-spacing:.02em;color:var(--text);margin-bottom:7px}
.field label .req{color:var(--copper-bright)}
.field .opt{color:var(--muted);font-weight:400;font-size:.78rem;letter-spacing:.02em}
.input,.select,.textarea{width:100%;background:var(--bg-elev-2);border:1px solid var(--line-strong);
  border-radius:var(--r-sm);color:var(--ink);font-family:var(--ff-body);font-size:1rem;
  padding:12px 14px;transition:border-color .18s,box-shadow .18s}
.textarea{min-height:130px;resize:vertical}
.select{appearance:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='none' stroke='%238f9fb2' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M4 6l4 4 4-4'/%3E%3C/svg%3E");
  background-repeat:no-repeat;background-position:right 14px center;padding-right:40px}
.input::placeholder,.textarea::placeholder{color:#8a99ad}
.input:focus,.select:focus,.textarea:focus{outline:none;border-color:var(--copper);
  box-shadow:0 0 0 3px var(--copper-soft)}
.field .err{margin-top:6px;font-size:.82rem;color:#f0a3a3}   /* stays in the a11y tree so aria-describedby is reliable */
.field .err:empty{display:none}
.field.invalid .input,.field.invalid .select,.field.invalid .textarea{border-color:#c8556a;box-shadow:0 0 0 3px rgba(200,85,106,.12)}
.hp{position:absolute;left:-9999px;width:1px;height:1px;opacity:0}
.form-actions{display:flex;align-items:center;gap:16px;flex-wrap:wrap;margin-top:6px}
.form-note{font-size:.86rem;color:var(--muted);margin:0}
.form-status{margin-top:16px;padding:13px 16px;border-radius:var(--r-sm);font-size:.94rem;display:none}
.form-status.ok{display:block;background:rgba(74,169,110,.12);border:1px solid rgba(74,169,110,.4);color:#a7e0bd}
.form-status.bad{display:block;background:rgba(200,85,106,.1);border:1px solid rgba(200,85,106,.4);color:#f0b3bd}

/* ---- footer --------------------------------------------------------------- */
.site-footer{border-top:1px solid var(--line);background:var(--bg-elev-2);padding-block:40px}
.foot{display:flex;justify-content:space-between;align-items:center;gap:24px;flex-wrap:wrap}
.foot small{color:var(--muted);font-size:.86rem}
.foot-links{display:flex;gap:22px;list-style:none;margin:0;padding:0}
.foot-links a{color:var(--text);font-size:.9rem}

/* ---- responsive ----------------------------------------------------------- */
@media(max-width:900px){
  .cards,.steps{grid-template-columns:1fr}
  .why-grid,.contact-grid{grid-template-columns:1fr}
  .stats{grid-template-columns:1fr 1fr}
  .grid2{grid-template-columns:1fr}
}
@media(max-width:760px){
  .nav-toggle{display:inline-flex}
  .nav-links{display:none}
  .nav-cta{display:none}
  .nav-menu{position:fixed;inset:70px 0 auto 0;background:var(--bg-elev);border-bottom:1px solid var(--line);
    flex-direction:column;align-items:stretch;gap:0;
    transform:translateY(-12px);opacity:0;visibility:hidden;transition:opacity .2s,transform .2s,visibility .2s;
    padding:12px var(--gut) 22px;z-index:99}
  .nav-menu.open{opacity:1;visibility:visible;transform:none}
  .nav-menu .nav-links{display:flex;flex-direction:column;align-items:stretch;gap:2px}
  .nav-menu .nav-links a{padding:13px 4px;border-bottom:1px solid var(--line);font-size:1.05rem}
  .nav-menu>.btn-primary{display:inline-flex;width:100%;margin-top:16px}
  .foot-links a{display:inline-block;padding:8px 4px}
}
@media(max-width:460px){
  .stats{grid-template-columns:1fr}
  .brand-name span{display:none}
  .hero-actions{flex-direction:column}
  .hero-actions .btn{width:100%}
}

/* ---- reduced motion ------------------------------------------------------- */
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms!important;transition-duration:.001ms!important}
  .reveal{opacity:1;transform:none}
  .span-rail,.hero-blueprint .grid,.hero-blueprint .watermark{transform:none!important}
}