/* =========================================================
   Sahara Energy Resource s.r.o — styles
   ========================================================= */

:root {
  /* Brand palette */
  --navy-900: #07171f;
  --navy-800: #0b1f2a;
  --navy-700: #102a38;
  --navy-600: #163847;
  --line: rgba(255, 255, 255, 0.09);

  --sand-300: #ffd39b;
  --amber-400: #ffb347;
  --orange-500: #ff8c42;
  --coral-500: #f25c54;
  --teal-400: #3fd0c9;

  --text: #eaf2f5;
  --text-muted: #9fb3bd;
  --text-faint: #6e8590;

  --bg: var(--navy-900);
  --surface: var(--navy-800);
  --surface-2: var(--navy-700);

  --grad-warm: linear-gradient(120deg, #ffd39b 0%, #ffb347 35%, #ff8c42 70%, #f25c54 100%);
  --grad-warm-soft: linear-gradient(135deg, rgba(255, 179, 71, 0.18), rgba(242, 92, 84, 0.10));

  --radius: 18px;
  --radius-sm: 12px;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  --shadow-sm: 0 10px 30px rgba(0, 0, 0, 0.30);

  --max: 1180px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);

  --font-display: "Sora", system-ui, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

* { margin: 0; }

html { scroll-behavior: smooth; scroll-padding-top: 90px; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img, svg { display: block; max-width: 100%; }

a { color: inherit; text-decoration: none; }

h1, h2, h3, h4 { font-family: var(--font-display); line-height: 1.1; font-weight: 700; }

ul { list-style: none; padding: 0; }

.container { width: 100%; max-width: var(--max); margin-inline: auto; padding-inline: 24px; }
.container.narrow { max-width: 820px; }

.grad-text {
  background: var(--grad-warm);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.96rem;
  padding: 13px 26px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s, color 0.25s;
  white-space: nowrap;
}
.btn-primary {
  background: var(--grad-warm);
  color: #2a1402;
  box-shadow: 0 10px 28px rgba(255, 140, 66, 0.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 36px rgba(255, 140, 66, 0.45); }
.btn-ghost {
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--line);
  color: var(--text);
}
.btn-ghost:hover { background: rgba(255, 255, 255, 0.09); transform: translateY(-2px); }
.btn-block { width: 100%; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  background: rgba(7, 23, 31, 0.72);
  border-bottom: 1px solid transparent;
  transition: background 0.3s, border-color 0.3s;
}
.site-header.scrolled {
  background: rgba(7, 23, 31, 0.92);
  border-bottom-color: var(--line);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  height: 72px;
}
.brand { display: inline-flex; align-items: center; gap: 12px; }
.brand-mark { border-radius: 10px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.05; }
.brand-text strong { font-family: var(--font-display); font-size: 1.02rem; letter-spacing: 0.2px; }
.brand-text em { font-style: normal; font-size: 0.72rem; color: var(--text-faint); letter-spacing: 1px; text-transform: uppercase; }

.main-nav { display: flex; align-items: center; gap: 28px; }
.main-nav a { font-size: 0.94rem; color: var(--text-muted); font-weight: 500; transition: color 0.2s; }
.main-nav a:hover { color: var(--text); }
.main-nav .nav-cta { color: #2a1402; }
.main-nav .nav-cta:hover { color: #2a1402; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  width: 24px; height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.3s var(--ease), opacity 0.3s;
}
.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); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: clamp(70px, 12vw, 140px) 0 clamp(60px, 9vw, 110px);
  overflow: hidden;
  isolation: isolate;
}
.hero-bg { position: absolute; inset: 0; z-index: -1; }
.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.5;
}
.glow-a {
  width: 520px; height: 520px;
  top: -160px; right: -120px;
  background: radial-gradient(circle, rgba(255, 140, 66, 0.55), transparent 65%);
}
.glow-b {
  width: 460px; height: 460px;
  bottom: -200px; left: -140px;
  background: radial-gradient(circle, rgba(63, 208, 201, 0.35), transparent 65%);
}
.hero-inner { max-width: 880px; }
.eyebrow {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.8rem;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--sand-300);
  background: var(--grad-warm-soft);
  border: 1px solid rgba(255, 179, 71, 0.25);
  padding: 7px 16px;
  border-radius: 999px;
  margin-bottom: 26px;
}
.hero-title {
  font-size: clamp(2.4rem, 6.2vw, 4.4rem);
  font-weight: 800;
  letter-spacing: -1.5px;
  margin-bottom: 22px;
}
.hero-sub {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-muted);
  max-width: 640px;
  margin-bottom: 34px;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }

.hero-trust {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 40px;
  margin-top: 54px;
  padding-top: 34px;
  border-top: 1px solid var(--line);
}
.hero-trust li { display: flex; flex-direction: column; }
.hero-trust strong { font-family: var(--font-display); font-size: 1.5rem; }
.hero-trust span { font-size: 0.86rem; color: var(--text-faint); }

/* ---------- Section scaffolding ---------- */
.section { padding: clamp(70px, 10vw, 120px) 0; }
.section-alt {
  background: var(--surface);
  border-block: 1px solid var(--line);
}

.section-head { max-width: 720px; margin: 0 auto clamp(40px, 6vw, 64px); text-align: center; }
.kicker {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.78rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--orange-500);
  margin-bottom: 14px;
}
.section-title {
  font-size: clamp(1.8rem, 4.2vw, 2.9rem);
  letter-spacing: -0.8px;
  margin-bottom: 16px;
}
.section-lead { color: var(--text-muted); font-size: 1.06rem; }
.section-lead em { color: var(--text-faint); }

/* ---------- Grids ---------- */
.grid { display: grid; gap: 22px; }
.grid-services { grid-template-columns: repeat(4, 1fr); }
.grid-steps { grid-template-columns: repeat(4, 1fr); counter-reset: none; }
.grid-sectors { grid-template-columns: repeat(4, 1fr); }
.grid-cases { grid-template-columns: repeat(3, 1fr); }

/* ---------- Cards ---------- */
.card {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.045), rgba(255, 255, 255, 0.015));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 26px;
  transition: transform 0.3s var(--ease), border-color 0.3s, box-shadow 0.3s;
}
.card:hover {
  transform: translateY(-6px);
  border-color: rgba(255, 179, 71, 0.4);
  box-shadow: var(--shadow-sm);
}
.card-icon {
  width: 52px; height: 52px;
  display: grid; place-items: center;
  font-size: 1.5rem;
  border-radius: 14px;
  background: var(--grad-warm-soft);
  border: 1px solid rgba(255, 179, 71, 0.25);
  margin-bottom: 18px;
}
.card h3 { font-size: 1.12rem; margin-bottom: 10px; }
.card p { color: var(--text-muted); font-size: 0.95rem; }

/* ---------- Steps ---------- */
.step {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px 26px 28px;
  overflow: hidden;
}
.step::before {
  content: "";
  position: absolute; top: 0; left: 0;
  width: 100%; height: 3px;
  background: var(--grad-warm);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.4s var(--ease);
}
.step:hover::before { transform: scaleX(1); }
.step-num {
  font-family: var(--font-display);
  font-size: 2.4rem; font-weight: 800;
  background: var(--grad-warm);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  display: block; margin-bottom: 14px;
}
.step h3 { font-size: 1.18rem; margin-bottom: 8px; }
.step p { color: var(--text-muted); font-size: 0.94rem; }

/* ---------- Sectors ---------- */
.sector {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: transform 0.3s var(--ease), background 0.3s;
}
.sector:hover { transform: translateY(-5px); background: var(--surface-2); }
.sector h3 { font-size: 1.1rem; margin-bottom: 10px; }
.sector p { color: var(--text-muted); font-size: 0.94rem; }

/* ---------- Cases ---------- */
.case {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.015));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  display: flex; flex-direction: column; gap: 12px;
  transition: transform 0.3s var(--ease), border-color 0.3s;
}
.case:hover { transform: translateY(-6px); border-color: rgba(255, 179, 71, 0.35); }
.case-tag {
  align-self: flex-start;
  font-family: var(--font-display);
  font-size: 0.72rem; letter-spacing: 1px; text-transform: uppercase;
  color: var(--sand-300);
  background: var(--grad-warm-soft);
  border: 1px solid rgba(255, 179, 71, 0.25);
  padding: 5px 12px; border-radius: 999px;
}
.case h3 { font-size: 1.16rem; }
.case p { color: var(--text-muted); font-size: 0.94rem; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: auto; }
.chips li {
  font-size: 0.78rem; color: var(--text-faint);
  border: 1px solid var(--line); border-radius: 999px;
  padding: 4px 12px;
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 56px;
  align-items: center;
}
.about-copy .kicker { text-align: left; }
.about-copy .section-title { text-align: left; }
.about-copy p { color: var(--text-muted); margin-bottom: 16px; }
.check-list { display: grid; gap: 12px; margin: 22px 0 28px; }
.check-list li {
  position: relative; padding-left: 32px;
  color: var(--text); font-weight: 500;
}
.check-list li::before {
  content: "✓";
  position: absolute; left: 0; top: 0;
  width: 22px; height: 22px;
  display: grid; place-items: center;
  font-size: 0.72rem; font-weight: 700;
  color: #2a1402;
  background: var(--grad-warm);
  border-radius: 50%;
}

.about-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}
.stat {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 22px;
  text-align: center;
}
.stat-num {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 2.8rem);
  font-weight: 800;
  background: var(--grad-warm);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  display: block;
}
.stat-label { font-size: 0.86rem; color: var(--text-muted); }

/* ---------- CTA banner ---------- */
.cta-banner {
  background:
    radial-gradient(circle at 20% 30%, rgba(255, 140, 66, 0.18), transparent 50%),
    radial-gradient(circle at 80% 70%, rgba(63, 208, 201, 0.14), transparent 50%),
    var(--navy-800);
  border-block: 1px solid var(--line);
}
.cta-inner { text-align: center; padding: clamp(56px, 8vw, 90px) 0; max-width: 720px; margin-inline: auto; }
.cta-inner h2 { font-size: clamp(1.8rem, 4vw, 2.8rem); letter-spacing: -0.8px; margin-bottom: 14px; }
.cta-inner p { color: var(--text-muted); font-size: 1.06rem; margin-bottom: 28px; }
.cta-inner .hero-actions { justify-content: center; }

/* ---------- FAQ ---------- */
.faq-list { display: grid; gap: 14px; }
.faq-item {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: 20px 24px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.02rem;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-size: 1.5rem; color: var(--orange-500);
  transition: transform 0.3s var(--ease);
  line-height: 1;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-body { padding: 0 24px 20px; }
.faq-body p { color: var(--text-muted); font-size: 0.96rem; }

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: start;
}
.contact-copy .kicker, .contact-copy .section-title { text-align: left; }
.contact-copy > p { color: var(--text-muted); margin-bottom: 28px; }
.contact-details { display: grid; gap: 18px; }
.contact-details li { display: flex; flex-direction: column; gap: 2px; }
.contact-label {
  font-size: 0.74rem; letter-spacing: 1px; text-transform: uppercase;
  color: var(--text-faint); font-family: var(--font-display);
}
.contact-value { font-size: 1rem; color: var(--text); }
.contact-value a { color: var(--sand-300); }

.contact-form {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow-sm);
}
.field { margin-bottom: 18px; }
.field label {
  display: block; margin-bottom: 7px;
  font-size: 0.86rem; font-weight: 500; color: var(--text-muted);
}
.field input, .field textarea {
  width: 100%;
  background: var(--navy-900);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 13px 15px;
  color: var(--text);
  font-family: var(--font-body);
  font-size: 0.96rem;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.field input::placeholder, .field textarea::placeholder { color: var(--text-faint); }
.field input:focus, .field textarea:focus {
  outline: none;
  border-color: var(--orange-500);
  box-shadow: 0 0 0 3px rgba(255, 140, 66, 0.18);
}
.field textarea { resize: vertical; }
.form-note { margin-top: 14px; font-size: 0.9rem; min-height: 1.2em; }
.form-note.ok { color: var(--teal-400); }
.form-note.err { color: var(--coral-500); }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--navy-900);
  border-top: 1px solid var(--line);
  padding-top: 60px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1.3fr 2fr;
  gap: 40px;
  padding-bottom: 40px;
}
.footer-brand p { color: var(--text-faint); margin-top: 14px; max-width: 280px; font-size: 0.94rem; }
.footer-nav { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.footer-nav h4 {
  font-size: 0.82rem; letter-spacing: 1px; text-transform: uppercase;
  color: var(--text); margin-bottom: 14px;
}
.footer-nav a { display: block; color: var(--text-muted); font-size: 0.92rem; padding: 4px 0; transition: color 0.2s; }
.footer-nav a:hover { color: var(--sand-300); }
.footer-bottom {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between;
  gap: 10px;
  padding: 22px 24px;
  border-top: 1px solid var(--line);
  margin-top: 0;
}
.footer-bottom p { font-size: 0.86rem; color: var(--text-faint); }

/* ---------- Back to top ---------- */
.to-top {
  position: fixed;
  right: 24px; bottom: 24px;
  width: 46px; height: 46px;
  display: grid; place-items: center;
  background: var(--grad-warm);
  color: #2a1402;
  border-radius: 50%;
  font-size: 1.2rem; font-weight: 700;
  box-shadow: var(--shadow-sm);
  opacity: 0; visibility: hidden; transform: translateY(12px);
  transition: opacity 0.3s, transform 0.3s, visibility 0.3s;
  z-index: 40;
}
.to-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.to-top:hover { transform: translateY(-3px); }

/* ---------- Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.in { opacity: 1; transform: translateY(0); }

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .grid-services, .grid-steps, .grid-sectors { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 860px) {
  .nav-toggle { display: flex; }
  .main-nav {
    position: fixed;
    inset: 72px 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    background: rgba(7, 23, 31, 0.98);
    border-bottom: 1px solid var(--line);
    padding: 18px 24px 26px;
    transform: translateY(-12px);
    opacity: 0; pointer-events: none;
    transition: transform 0.3s var(--ease), opacity 0.3s;
  }
  .main-nav.open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .main-nav a { padding: 12px 4px; border-bottom: 1px solid var(--line); }
  .main-nav .nav-cta { text-align: center; margin-top: 10px; border-bottom: 0; }

  .grid-cases { grid-template-columns: 1fr; }
  .about-grid, .contact-grid { grid-template-columns: 1fr; gap: 36px; }
  .footer-inner { grid-template-columns: 1fr; }
}

@media (max-width: 540px) {
  .grid-services, .grid-steps, .grid-sectors { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: 1fr 1fr; }
  .footer-nav { grid-template-columns: 1fr 1fr; }
  .contact-form { padding: 24px 20px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
  html { scroll-behavior: auto; }
}