/* =========================================================
   Research Development Institute — rdi.kz
   Static corporate site. Modern tech dark theme.
   ========================================================= */

:root{
  --bg:#070A12;
  --bg-2:#0B101C;
  --surface:rgba(255,255,255,.035);
  --surface-2:rgba(255,255,255,.06);
  --border:rgba(255,255,255,.09);
  --border-2:rgba(255,255,255,.16);
  --text:#E8ECF4;
  --muted:#98A4B8;
  --muted-2:#6F7C93;
  --accent:#2FD3E1;
  --accent-2:#7C6BFF;
  --accent-soft:rgba(47,211,225,.12);
  --grad:linear-gradient(135deg,#2FD3E1 0%,#5B8CFF 45%,#7C6BFF 100%);
  --radius:16px;
  --radius-lg:24px;
  --maxw:1200px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --font:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',Arial,sans-serif;
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--font);
  background:var(--bg);
  color:var(--text);
  font-size:16px;
  line-height:1.65;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
img,svg{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
ul{margin:0;padding:0;list-style:none}
h1,h2,h3,h4{margin:0;line-height:1.15;letter-spacing:-.02em;font-weight:700}
p{margin:0}
button,input,textarea,select{font:inherit;color:inherit}

.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 24px}
.section{padding:104px 0;position:relative}
.section--tight{padding:80px 0}

/* ---------- decorative background ---------- */
.bg-fx{position:fixed;inset:0;z-index:0;pointer-events:none;overflow:hidden}
.bg-fx::before{
  content:'';position:absolute;inset:0;
  background-image:linear-gradient(rgba(255,255,255,.028) 1px,transparent 1px),
                   linear-gradient(90deg,rgba(255,255,255,.028) 1px,transparent 1px);
  background-size:64px 64px;
  mask-image:radial-gradient(ellipse 90% 60% at 50% 0%,#000 20%,transparent 75%);
  -webkit-mask-image:radial-gradient(ellipse 90% 60% at 50% 0%,#000 20%,transparent 75%);
}
.glow{position:absolute;border-radius:50%;filter:blur(120px);opacity:.5}
.glow--1{width:620px;height:620px;top:-260px;left:-120px;background:rgba(47,211,225,.22)}
.glow--2{width:560px;height:560px;top:-180px;right:-160px;background:rgba(124,107,255,.22)}
.glow--3{width:700px;height:700px;top:1500px;left:40%;background:rgba(91,140,255,.10)}

/* ---------- header ---------- */
.header{
  position:fixed;top:0;left:0;right:0;z-index:100;
  transition:background .3s var(--ease),border-color .3s var(--ease),backdrop-filter .3s;
  border-bottom:1px solid transparent;
}
.header.is-stuck{
  background:rgba(7,10,18,.82);
  backdrop-filter:blur(16px);
  -webkit-backdrop-filter:blur(16px);
  border-bottom-color:var(--border);
}
.header__inner{display:flex;align-items:center;gap:24px;height:74px}
.brand{display:flex;align-items:center;gap:12px;flex-shrink:0}
.brand__mark{width:38px;height:38px;flex:none}
.brand__text{display:flex;flex-direction:column;line-height:1.05}
.brand__name{font-weight:800;font-size:19px;letter-spacing:.02em}
.brand__sub{font-size:10.5px;color:var(--muted-2);letter-spacing:.09em;text-transform:uppercase;white-space:nowrap}

.nav{margin-left:auto;display:flex;align-items:center;gap:4px}
.nav a{
  padding:9px 14px;border-radius:10px;font-size:14.5px;color:var(--muted);
  transition:color .2s,background .2s;white-space:nowrap
}
.nav a:hover{color:var(--text);background:var(--surface)}

.header__actions{display:flex;align-items:center;gap:10px;flex-shrink:0}

.lang{display:flex;gap:2px;padding:3px;background:var(--surface);border:1px solid var(--border);border-radius:11px}
.lang button{
  background:none;border:0;cursor:pointer;padding:5px 10px;border-radius:8px;
  font-size:12.5px;font-weight:600;color:var(--muted-2);letter-spacing:.04em;
  transition:.2s
}
.lang button:hover{color:var(--text)}
.lang button.is-active{background:var(--surface-2);color:var(--text);box-shadow:0 0 0 1px var(--border)}

.burger{display:none;width:42px;height:42px;border:1px solid var(--border);background:var(--surface);border-radius:11px;cursor:pointer;padding:0;place-items:center}
.burger span{display:block;width:18px;height:1.6px;background:var(--text);margin:3.5px auto;transition:.25s var(--ease)}
.burger.is-open span:nth-child(1){transform:translateY(5.1px) rotate(45deg)}
.burger.is-open span:nth-child(2){opacity:0}
.burger.is-open span:nth-child(3){transform:translateY(-5.1px) rotate(-45deg)}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:9px;
  padding:13px 24px;border-radius:12px;font-size:15px;font-weight:600;
  border:1px solid transparent;cursor:pointer;transition:.25s var(--ease);white-space:nowrap;
  text-align:center
}
.btn--primary{background:var(--grad);color:#05070D;box-shadow:0 8px 30px -10px rgba(47,211,225,.65)}
.btn--primary:hover{transform:translateY(-2px);box-shadow:0 14px 40px -12px rgba(47,211,225,.8)}
.btn--ghost{background:var(--surface);border-color:var(--border-2);color:var(--text)}
.btn--ghost:hover{background:var(--surface-2);border-color:var(--accent);color:#fff}
.btn--sm{padding:10px 18px;font-size:14px;border-radius:11px}
.btn--block{width:100%}

/* ---------- eyebrow / headings ---------- */
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;padding:6px 14px;border-radius:999px;
  background:var(--accent-soft);border:1px solid rgba(47,211,225,.25);
  font-size:12.5px;font-weight:600;letter-spacing:.09em;text-transform:uppercase;color:var(--accent);
  margin-bottom:20px
}
.eyebrow .dot{width:6px;height:6px;border-radius:50%;background:var(--accent);box-shadow:0 0 10px var(--accent)}
.h1{font-size:clamp(36px,6vw,62px);font-weight:800;letter-spacing:-.035em}
.h2{font-size:clamp(28px,3.8vw,42px)}
.h3{font-size:20px}
.lead{color:var(--muted);font-size:clamp(16px,1.6vw,18.5px);max-width:64ch}
.section__head{max-width:760px;margin-bottom:56px}
.section__head--center{margin-left:auto;margin-right:auto;text-align:center}
.gradient-text{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}

/* ---------- hero ---------- */
.hero{position:relative;z-index:1;padding:170px 0 90px}
.hero__grid{display:grid;grid-template-columns:1.1fr .9fr;gap:64px;align-items:center}
.hero p.lead{margin-top:22px}
.hero__cta{display:flex;gap:14px;margin-top:36px;flex-wrap:wrap}
.hero__meta{display:flex;gap:28px;margin-top:44px;flex-wrap:wrap}
.hero__meta div{display:flex;flex-direction:column}
.hero__meta b{font-size:26px;font-weight:800;letter-spacing:-.02em}
.hero__meta span{font-size:13px;color:var(--muted-2)}

.hero__visual{position:relative;aspect-ratio:1/1;display:grid;place-items:center}
.orbit{position:absolute;border:1px solid var(--border);border-radius:50%;inset:0}
.orbit--1{inset:6%;animation:spin 34s linear infinite}
.orbit--2{inset:19%;border-style:dashed;border-color:rgba(255,255,255,.07);animation:spin 26s linear infinite reverse}
.orbit--3{inset:32%;animation:spin 18s linear infinite}
.orbit i{position:absolute;top:-4px;left:50%;width:8px;height:8px;margin-left:-4px;border-radius:50%;background:var(--accent);box-shadow:0 0 16px var(--accent)}
.orbit--2 i{background:var(--accent-2);box-shadow:0 0 16px var(--accent-2)}
.orbit--3 i{background:#5B8CFF;box-shadow:0 0 16px #5B8CFF}
@keyframes spin{to{transform:rotate(360deg)}}
.core{
  position:relative;width:44%;aspect-ratio:1;border-radius:50%;
  background:radial-gradient(circle at 30% 30%,rgba(47,211,225,.35),rgba(124,107,255,.18) 60%,transparent 72%);
  border:1px solid var(--border-2);display:grid;place-items:center;
  backdrop-filter:blur(6px)
}
.core svg{width:52%;opacity:.95}

/* ---------- marquee / trust strip ---------- */
.strip{border-top:1px solid var(--border);border-bottom:1px solid var(--border);background:rgba(255,255,255,.015)}
.strip__inner{display:flex;flex-wrap:wrap;gap:14px 40px;padding:22px 0;align-items:center;justify-content:space-between}
.strip__label{font-size:12.5px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted-2)}
.strip__items{display:flex;flex-wrap:wrap;gap:10px}
.chip{
  padding:7px 14px;border-radius:999px;border:1px solid var(--border);
  background:var(--surface);font-size:13px;color:var(--muted)
}

/* ---------- cards grid ---------- */
.grid{display:grid;gap:20px}
.grid--2{grid-template-columns:repeat(2,1fr)}
.grid--3{grid-template-columns:repeat(3,1fr)}
.grid--4{grid-template-columns:repeat(4,1fr)}

.card{
  position:relative;padding:30px;border-radius:var(--radius-lg);
  background:linear-gradient(180deg,rgba(255,255,255,.045),rgba(255,255,255,.015));
  border:1px solid var(--border);overflow:hidden;
  transition:transform .35s var(--ease),border-color .35s,background .35s
}
.card::after{
  content:'';position:absolute;inset:0;border-radius:inherit;pointer-events:none;
  background:radial-gradient(420px circle at var(--mx,50%) var(--my,0%),rgba(47,211,225,.10),transparent 60%);
  opacity:0;transition:opacity .35s
}
.card:hover{transform:translateY(-4px);border-color:var(--border-2)}
.card:hover::after{opacity:1}
.card__icon{
  width:50px;height:50px;border-radius:14px;display:grid;place-items:center;margin-bottom:20px;
  background:var(--accent-soft);border:1px solid rgba(47,211,225,.22);color:var(--accent)
}
.card__icon svg{width:24px;height:24px}
.card h3{font-size:19px;margin-bottom:10px}
.card p{color:var(--muted);font-size:15px}
.card__list{margin-top:18px;display:flex;flex-direction:column;gap:8px}
.card__list li{position:relative;padding-left:20px;font-size:14px;color:var(--muted)}
.card__list li::before{
  content:'';position:absolute;left:0;top:9px;width:6px;height:6px;border-radius:2px;
  background:var(--accent);opacity:.8
}
.card--wide{grid-column:span 2}

/* ---------- about ---------- */
.about{display:grid;grid-template-columns:1fr 1fr;gap:64px;align-items:start}
.about__points{display:grid;gap:16px;margin-top:32px}
.point{display:flex;gap:16px;align-items:flex-start}
.point__num{
  flex:none;width:38px;height:38px;border-radius:11px;display:grid;place-items:center;
  background:var(--surface);border:1px solid var(--border);font-size:13px;font-weight:700;color:var(--accent)
}
.point h4{font-size:16px;margin-bottom:4px}
.point p{font-size:14.5px;color:var(--muted)}

.stat-box{
  display:grid;grid-template-columns:1fr 1fr;gap:1px;background:var(--border);
  border:1px solid var(--border);border-radius:var(--radius-lg);overflow:hidden
}
.stat{background:var(--bg-2);padding:30px 26px}
.stat b{display:block;font-size:38px;font-weight:800;letter-spacing:-.03em;line-height:1}
.stat span{display:block;margin-top:8px;font-size:13.5px;color:var(--muted)}

/* ---------- process ---------- */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;counter-reset:s}
.step{position:relative;padding-top:30px}
.step::before{
  content:'';position:absolute;top:9px;left:0;right:0;height:1px;
  background:linear-gradient(90deg,var(--accent),transparent)
}
.step__n{
  position:absolute;top:0;left:0;width:20px;height:20px;border-radius:50%;
  background:var(--bg);border:1px solid var(--accent);display:grid;place-items:center;
  font-size:10px;font-weight:700;color:var(--accent)
}
.step h4{font-size:17px;margin-bottom:8px}
.step p{font-size:14.5px;color:var(--muted)}

/* ---------- journal ---------- */
.journal{
  display:grid;grid-template-columns:1.15fr .85fr;gap:48px;align-items:center;
  padding:48px;border-radius:var(--radius-lg);
  background:linear-gradient(135deg,rgba(47,211,225,.09),rgba(124,107,255,.09));
  border:1px solid var(--border-2);position:relative;overflow:hidden
}
.journal::before{
  content:'';position:absolute;width:420px;height:420px;right:-120px;top:-160px;border-radius:50%;
  background:rgba(124,107,255,.18);filter:blur(90px)
}
.journal > *{position:relative}
.journal h3{font-size:clamp(22px,2.6vw,30px);margin-bottom:14px}
.journal p{color:var(--muted);font-size:15.5px}
.journal__meta{display:flex;flex-wrap:wrap;gap:10px;margin:24px 0 28px}
.journal__cover{
  border-radius:var(--radius);border:1px solid var(--border-2);
  background:linear-gradient(160deg,#0E1626,#080C16);padding:32px;
  box-shadow:0 30px 60px -30px rgba(0,0,0,.9)
}
.journal__cover .jc-top{font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:var(--accent);margin-bottom:22px}
.journal__cover .jc-title{font-size:26px;font-weight:800;letter-spacing:-.02em;line-height:1.15}
.journal__cover .jc-rule{height:2px;width:64px;background:var(--grad);margin:20px 0}
.journal__cover .jc-sub{font-size:13px;color:var(--muted-2);line-height:1.6}

/* ---------- contacts ---------- */
.contacts{display:grid;grid-template-columns:.9fr 1.1fr;gap:48px;align-items:start}
.contact-list{display:grid;gap:14px;margin-top:32px}
.contact-item{
  display:flex;gap:14px;align-items:center;padding:18px 20px;border-radius:var(--radius);
  background:var(--surface);border:1px solid var(--border);transition:.25s var(--ease)
}
.contact-item:hover{border-color:var(--border-2);background:var(--surface-2)}
.contact-item__ic{
  flex:none;width:40px;height:40px;border-radius:11px;display:grid;place-items:center;
  background:var(--accent-soft);color:var(--accent)
}
.contact-item__ic svg{width:19px;height:19px}
.contact-item span{display:block;font-size:12px;color:var(--muted-2);letter-spacing:.05em;text-transform:uppercase}
.contact-item b{font-weight:600;font-size:15.5px;word-break:break-word}

.form{
  padding:34px;border-radius:var(--radius-lg);border:1px solid var(--border);
  background:linear-gradient(180deg,rgba(255,255,255,.045),rgba(255,255,255,.012))
}
.field{margin-bottom:16px}
.field label{display:block;font-size:13px;color:var(--muted);margin-bottom:7px}
.field input,.field textarea,.field select{
  width:100%;padding:13px 15px;border-radius:12px;
  background:rgba(0,0,0,.28);border:1px solid var(--border);
  outline:none;transition:.2s;font-size:15px
}
.field input:focus,.field textarea:focus,.field select:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(47,211,225,.12)}
.field textarea{resize:vertical;min-height:120px}
.field select option{background:#0B101C}
.form__note{font-size:12.5px;color:var(--muted-2);margin-top:14px;text-align:center}

/* ---------- CTA band ---------- */
.cta-band{
  text-align:center;padding:64px 40px;border-radius:var(--radius-lg);
  background:linear-gradient(135deg,rgba(47,211,225,.10),rgba(124,107,255,.10));
  border:1px solid var(--border-2)
}
.cta-band h2{margin-bottom:14px}
.cta-band p{color:var(--muted);max-width:56ch;margin:0 auto 30px}

/* ---------- footer ---------- */
.footer{border-top:1px solid var(--border);padding:56px 0 32px;position:relative;z-index:1;background:rgba(0,0,0,.2)}
.footer__grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:40px}
.footer h5{font-size:13px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted-2);margin:0 0 16px;font-weight:600}
.footer li{margin-bottom:9px}
.footer a{font-size:14.5px;color:var(--muted);transition:color .2s}
.footer a:hover{color:var(--accent)}
.footer__about{font-size:14.5px;color:var(--muted);margin-top:16px;max-width:34ch}
.footer__bottom{
  margin-top:44px;padding-top:24px;border-top:1px solid var(--border);
  display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;
  font-size:13.5px;color:var(--muted-2)
}

/* ---------- reveal animation ---------- */
.reveal{opacity:0;transform:translateY(22px);transition:opacity .7s var(--ease),transform .7s var(--ease)}
.reveal.is-in{opacity:1;transform:none}

/* ---------- responsive ---------- */
@media (max-width:1040px){
  .grid--4{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
  .footer__grid{grid-template-columns:1fr 1fr}
}
@media (max-width:900px){
  .nav{
    position:fixed;top:74px;left:0;right:0;flex-direction:column;align-items:stretch;gap:2px;
    padding:16px 24px 26px;background:rgba(7,10,18,.97);backdrop-filter:blur(16px);
    border-bottom:1px solid var(--border);
    transform:translateY(-12px);opacity:0;pointer-events:none;transition:.25s var(--ease)
  }
  .nav.is-open{transform:none;opacity:1;pointer-events:auto}
  .nav a{padding:13px 12px;font-size:16px}
  .burger{display:grid}
  .hero{padding:130px 0 70px}
  .hero__grid{grid-template-columns:1fr;gap:48px}
  .hero__visual{max-width:400px;margin:0 auto;width:100%}
  .about,.contacts,.journal{grid-template-columns:1fr;gap:36px}
  .grid--3,.grid--2{grid-template-columns:1fr}
  .card--wide{grid-column:auto}
  .journal{padding:32px}
}
@media (max-width:600px){
  .section{padding:72px 0}
  .container{padding:0 18px}
  .grid--4{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .footer__grid{grid-template-columns:1fr}
  .brand__sub{display:none}
  .stat-box{grid-template-columns:1fr}
  .form{padding:24px}
  .cta-band{padding:44px 24px}
  .hero__cta .btn{width:100%}
}
@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important;scroll-behavior:auto!important}
  .reveal{opacity:1;transform:none}
}