/* ==========================================================================
   Exotech AI — landing page styles
   Brand: indigo → violet, Inter typeface. Light base with dark accent
   sections. Auto dark mode via prefers-color-scheme. Fully responsive.
   ========================================================================== */

:root{
  --brand:#4f46e5;        /* indigo-600 */
  --brand2:#7c3aed;       /* violet-600 */
  --brand-light:#a5b4fc;
  --bg:#ffffff;
  --surface:#f8fafc;
  --ink:#0f172a;
  --muted:#64748b;
  --line:#e2e8f0;
  --dark-bg:#0b1020;
  --grad:linear-gradient(135deg,var(--brand),var(--brand2));
  --maxw:1200px;
}
@media (prefers-color-scheme: dark){
  :root{
    --bg:#0b0f1a; --surface:#141b2d; --ink:#e6e9f2; --muted:#9aa3b7;
    --line:#232b3e; --dark-bg:#070a12;
  }
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:'Inter',-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg); color:var(--ink); line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%}
.container{max-width:var(--maxw); margin:0 auto; padding:0 24px}
section[id]{scroll-margin-top:84px}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex; align-items:center; justify-content:center; gap:8px;
  font-weight:600; font-size:15px; padding:13px 26px; border-radius:11px;
  border:0; cursor:pointer; text-decoration:none; line-height:1;
  background:var(--grad); color:#fff; transition:transform .2s ease, box-shadow .2s ease, border-color .2s ease, color .2s ease;
}
.btn:hover{transform:translateY(-2px)}
.btn--primary{box-shadow:0 8px 24px rgba(79,70,229,.35)}
.btn--primary:hover{box-shadow:0 12px 30px rgba(79,70,229,.45)}
.btn--ghost{background:transparent; color:var(--ink); border:1px solid var(--line)}
.btn--ghost:hover{border-color:var(--brand); color:var(--brand)}
.btn--sm{padding:10px 18px; font-size:14px; box-shadow:0 6px 18px rgba(79,70,229,.3)}
.btn--full{width:100%}

/* ---------- Nav ---------- */
.nav{
  position:fixed; top:0; left:0; right:0; z-index:100;
  background:color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter:saturate(180%) blur(14px); -webkit-backdrop-filter:saturate(180%) blur(14px);
  border-bottom:1px solid transparent; transition:border-color .3s, box-shadow .3s;
}
.nav.scrolled{border-bottom-color:var(--line); box-shadow:0 4px 24px rgba(0,0,0,.06)}
.nav__inner{display:flex; align-items:center; justify-content:space-between; height:72px}
.nav__logo{font-weight:800; font-size:22px; letter-spacing:-.02em; color:var(--ink); text-decoration:none}
.nav__logo span{background:var(--grad); -webkit-background-clip:text; background-clip:text; color:transparent}
.nav__links{display:flex; align-items:center; gap:30px; list-style:none; margin:0; padding:0}
.nav__links a{color:var(--ink); text-decoration:none; font-weight:500; font-size:15px; transition:color .2s}
.nav__links a:not(.btn):hover{color:var(--brand)}
.nav__toggle{display:none; flex-direction:column; gap:5px; background:none; border:0; cursor:pointer; padding:6px}
.nav__toggle span{display:block; width:24px; height:2px; background:var(--ink); border-radius:2px; transition:.3s}
.nav__toggle.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav__toggle.open span:nth-child(2){opacity:0}
.nav__toggle.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ---------- Hero ---------- */
.hero{position:relative; padding:168px 0 104px; text-align:center; overflow:hidden}
.hero__bg{position:absolute; inset:0; z-index:0; pointer-events:none;
  background:radial-gradient(circle at 50% -10%, color-mix(in srgb,var(--brand) 22%,transparent), transparent 55%)}
.hero__inner{position:relative; z-index:1; max-width:880px; margin:0 auto}
.hero__badge{display:inline-block; padding:8px 18px; border-radius:999px; margin-bottom:26px;
  background:color-mix(in srgb,var(--brand) 12%,transparent); color:var(--brand); font-weight:600; font-size:14px}
.hero__title{font-size:clamp(40px,7vw,72px); line-height:1.05; letter-spacing:-.03em; font-weight:800; margin:0 0 22px}
.hero__title span{background:var(--grad); -webkit-background-clip:text; background-clip:text; color:transparent}
.hero__sub{font-size:clamp(17px,2.2vw,21px); color:var(--muted); max-width:660px; margin:0 auto 38px}
.hero__cta{display:flex; gap:14px; justify-content:center; flex-wrap:wrap; margin-bottom:68px}
.hero__stats{display:flex; gap:56px; justify-content:center; flex-wrap:wrap}
.stat{display:flex; flex-direction:column}
.stat__num{font-size:42px; font-weight:800; letter-spacing:-.02em;
  background:var(--grad); -webkit-background-clip:text; background-clip:text; color:transparent}
.stat__label{color:var(--muted); font-size:14px; margin-top:4px}

/* ---------- Section shell ---------- */
.section{padding:104px 0}
.section__header{text-align:center; max-width:660px; margin:0 auto 60px}
.section__tag{display:inline-block; color:var(--brand); font-weight:700; font-size:13px;
  letter-spacing:.09em; text-transform:uppercase; margin-bottom:14px}
.section__header h2{font-size:clamp(30px,4.5vw,44px); letter-spacing:-.02em; margin:0 0 14px; font-weight:800}
.section__header p{color:var(--muted); font-size:18px; margin:0}
.section__header--light h2{color:#fff}
.section__header--light .section__tag{color:var(--brand-light)}
.section__header--light p{color:rgba(255,255,255,.72)}

/* ---------- Services ---------- */
.services__grid{display:grid; grid-template-columns:repeat(auto-fit,minmax(270px,1fr)); gap:24px}
.service-card{position:relative; background:var(--surface); border:1px solid var(--line);
  border-radius:20px; padding:32px; transition:transform .25s, box-shadow .25s, border-color .25s}
.service-card:hover{transform:translateY(-6px); box-shadow:0 24px 44px rgba(15,23,42,.10);
  border-color:color-mix(in srgb,var(--brand) 40%,var(--line))}
.service-card__icon{font-size:42px; margin-bottom:18px; line-height:1}
.service-card h3{font-size:20px; margin:0 0 10px}
.service-card p{color:var(--muted); font-size:15px; margin:0 0 18px}
.service-card__list{list-style:none; padding:0; margin:0}
.service-card__list li{position:relative; padding-left:24px; margin:8px 0; font-size:14.5px}
.service-card__list li::before{content:"✓"; position:absolute; left:0; color:var(--brand); font-weight:700}
.service-card--featured{
  background:linear-gradient(165deg, color-mix(in srgb,var(--brand) 9%,var(--surface)), var(--surface));
  border-color:color-mix(in srgb,var(--brand) 32%,var(--line))}
.service-card__badge{position:absolute; top:-13px; left:32px; background:var(--grad); color:#fff;
  font-size:12px; font-weight:700; padding:6px 14px; border-radius:999px; box-shadow:0 6px 16px rgba(79,70,229,.35)}

/* ---------- Why us (dark) ---------- */
.section--dark{background:var(--dark-bg); color:#fff}
.features__grid{display:grid; grid-template-columns:repeat(auto-fit,minmax(260px,1fr)); gap:30px 28px}
.feature__icon{font-size:38px; margin-bottom:14px; line-height:1}
.feature h4{font-size:18px; margin:0 0 8px; color:#fff}
.feature p{color:rgba(255,255,255,.68); font-size:15px; margin:0}

/* ---------- Process ---------- */
.process__steps{display:flex; align-items:stretch; justify-content:center; gap:16px; flex-wrap:wrap}
.step{flex:1; min-width:210px; background:var(--surface); border:1px solid var(--line);
  border-radius:18px; padding:30px 26px; text-align:center}
.step__num{font-size:34px; font-weight:800; margin-bottom:12px; letter-spacing:-.02em;
  background:var(--grad); -webkit-background-clip:text; background-clip:text; color:transparent}
.step h4{margin:0 0 8px; font-size:18px}
.step p{color:var(--muted); font-size:14.5px; margin:0}
.step__arrow{display:flex; align-items:center; color:var(--brand); font-size:26px; font-weight:700}

/* ---------- Contact (accent) ---------- */
.section--accent{background:var(--grad); color:#fff}
.contact__inner{display:grid; grid-template-columns:1fr 1fr; gap:56px; align-items:center}
.contact__info .section__tag{color:rgba(255,255,255,.9)}
.contact__info h2{color:#fff; font-size:clamp(28px,4vw,42px); letter-spacing:-.02em; margin:0 0 14px}
.contact__info p{color:rgba(255,255,255,.85); font-size:18px; margin:0}
.contact__details{margin-top:28px; display:flex; flex-direction:column; gap:14px}
.contact__link{display:inline-flex; align-items:center; gap:10px; color:#fff; text-decoration:none; font-weight:500}
.contact__link:hover{text-decoration:underline}
.contact__form{background:#fff; border-radius:22px; padding:34px; box-shadow:0 30px 60px rgba(15,23,42,.25)}
.form__group{margin-bottom:16px}
.form__group input,.form__group select,.form__group textarea{
  width:100%; padding:14px 16px; border:1px solid #e2e8f0; border-radius:11px;
  font:inherit; font-size:15px; color:#0f172a; background:#fff; transition:border-color .2s, box-shadow .2s}
.form__group input::placeholder,.form__group textarea::placeholder{color:#94a3b8}
.form__group input:focus,.form__group select:focus,.form__group textarea:focus{
  outline:none; border-color:var(--brand); box-shadow:0 0 0 3px rgba(79,70,229,.15)}
.form__group textarea{resize:vertical}

/* ---------- Footer ---------- */
.footer{background:var(--dark-bg); color:#fff; padding:64px 0 40px}
.footer__inner{display:grid; grid-template-columns:2fr 1fr 1.6fr; gap:36px; align-items:start}
.footer__brand .nav__logo{color:#fff}
.footer__brand p{color:rgba(255,255,255,.6); font-size:14px; margin:14px 0 0}
.footer__links{display:flex; flex-direction:column; gap:11px}
.footer__links a{color:rgba(255,255,255,.7); text-decoration:none; font-size:15px}
.footer__links a:hover{color:#fff}
.footer__copy{color:rgba(255,255,255,.6); font-size:14px; text-align:right}
.footer__copy p{margin:0 0 6px}
.footer__copy a{color:rgba(255,255,255,.82); text-decoration:none}
.footer__copy a:hover{text-decoration:underline}

/* ---------- Responsive ---------- */
@media (max-width:900px){
  .nav__toggle{display:flex}
  .nav__links{
    position:fixed; top:72px; left:0; right:0; flex-direction:column; align-items:stretch;
    gap:6px; background:var(--bg); border-bottom:1px solid var(--line); padding:16px 24px 22px;
    transform:translateY(-130%); transition:transform .32s ease; box-shadow:0 20px 40px rgba(0,0,0,.12)}
  .nav__links.open{transform:translateY(0)}
  .nav__links li{width:100%}
  .nav__links a:not(.btn){display:block; padding:12px 4px; border-bottom:1px solid var(--line)}
  .nav__links .btn{margin-top:10px; width:100%}
  .hero{padding:140px 0 84px}
  .hero__stats{gap:36px}
  .stat__num{font-size:36px}
  .section{padding:76px 0}
  .contact__inner{grid-template-columns:1fr; gap:36px}
  .process__steps{flex-direction:column; align-items:stretch}
  .step__arrow{justify-content:center; transform:rotate(90deg); padding:4px 0}
  .footer__inner{grid-template-columns:1fr; gap:26px}
  .footer__copy{text-align:left}
}
@media (max-width:480px){
  .hero__stats{gap:26px}
  .service-card,.contact__form{padding:26px}
}