/* ==========================================================================
   Cseppfolyós Nitrogén — design tokens
   ========================================================================== */
:root {
  --navy-900: #081B30;
  --navy-800: #0B2A4A;
  --navy-700: #124D8D;
  --navy-600: #1E63AC;
  --cyan-400: #1BC7E0;
  --cyan-300: #5EE3F5;
  --cyan-100: #D8F5FA;
  --frost-50: #F5FAFC;
  --frost-100: #EAF6FB;
  --steel-400: #7C93A8;
  --slate-600: #45566B;
  --ink-900: #0A1930;
  --amber-500: #F0A202;
  --white: #FFFFFF;

  --font-display: 'Space Grotesk', 'Segoe UI', sans-serif;
  --font-body: 'DM Sans', 'Segoe UI', sans-serif;

  --radius-sm: 10px;
  --radius-md: 18px;
  --radius-lg: 28px;

  --shadow-soft: 0 20px 50px -20px rgba(11,42,74,0.25);
  --shadow-glow: 0 0 0 1px rgba(27,199,224,0.15), 0 20px 60px -20px rgba(27,199,224,0.35);

  --ease-out: cubic-bezier(0.16,1,0.3,1);
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
}

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--ink-900);
  background: var(--frost-50);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { font-family: var(--font-display); line-height: 1.15; margin: 0 0 0.5em; font-weight: 700; color: var(--navy-900); }
h1 { font-size: clamp(2.1rem, 4.4vw, 3.4rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.7rem, 3vw, 2.5rem); letter-spacing: -0.01em; }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1em; color: var(--slate-600); }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul { margin: 0; padding: 0; list-style: none; }
button { font-family: inherit; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

.skip-link {
  position: absolute; left: -999px; top: auto;
  background: var(--navy-700); color: #fff; padding: 12px 20px; border-radius: var(--radius-sm);
  z-index: 1000;
}
.skip-link:focus { left: 16px; top: 16px; }

a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible {
  outline: 3px solid var(--cyan-400);
  outline-offset: 2px;
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  font-family: var(--font-display); font-weight: 600; font-size: 0.95rem;
  padding: 14px 26px; border-radius: 100px; border: none; cursor: pointer;
  transition: transform 220ms var(--ease-out), box-shadow 220ms var(--ease-out), background 220ms var(--ease-out);
  white-space: nowrap;
}
.btn svg { flex-shrink: 0; }
.btn-sm { padding: 10px 20px; font-size: 0.85rem; }
.btn-lg { padding: 16px 32px; font-size: 1rem; }
.btn-block { width: 100%; }

.btn-primary { background: var(--navy-700); color: #fff; box-shadow: 0 12px 30px -12px rgba(18,77,141,0.55); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 18px 36px -12px rgba(18,77,141,0.65); }

.btn-accent { background: linear-gradient(135deg, var(--cyan-400), var(--navy-600)); color: #fff; box-shadow: 0 12px 30px -10px rgba(27,199,224,0.55); }
.btn-accent:hover { transform: translateY(-2px); box-shadow: 0 18px 40px -10px rgba(27,199,224,0.65); }
.btn-accent:disabled { opacity: 0.65; cursor: not-allowed; transform: none; }

.btn-ghost { background: rgba(255,255,255,0.08); color: #fff; border: 1.5px solid rgba(255,255,255,0.35); backdrop-filter: blur(6px); }
.btn-ghost:hover { background: rgba(255,255,255,0.16); transform: translateY(-2px); }

/* ==========================================================================
   Header
   ========================================================================== */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  padding: 18px 0;
  transition: background 260ms var(--ease-out), padding 260ms var(--ease-out), box-shadow 260ms var(--ease-out);
}
.site-header.scrolled {
  background: rgba(245,250,252,0.85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  padding: 12px 0;
  box-shadow: 0 8px 30px -16px rgba(8,27,48,0.25);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: inline-flex; align-items: center; flex-shrink: 0; }
.brand-logo { height: 38px; width: auto; display: block; }
.brand-logo-light { display: none; }
.site-header:not(.scrolled) .brand-logo-dark { display: none; }
.site-header:not(.scrolled) .brand-logo-light { display: block; }

.main-nav ul { display: flex; gap: 30px; }
.main-nav a {
  font-family: var(--font-display); font-weight: 500; font-size: 0.95rem;
  color: var(--ink-900); position: relative; padding: 4px 0;
  transition: color 200ms var(--ease-out);
}
.site-header:not(.scrolled) .main-nav a { color: #fff; }
.main-nav a::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: -4px; height: 2px;
  background: var(--cyan-400); transition: right 220ms var(--ease-out);
}
.main-nav a:hover::after { right: 0; }

.header-actions { display: flex; align-items: center; gap: 20px; }
.header-phone { display: flex; align-items: center; gap: 8px; font-weight: 600; font-size: 0.92rem; color: var(--ink-900); }
.site-header:not(.scrolled) .header-phone { color: #fff; }

.nav-toggle { display: none; position: relative; z-index: 101; width: 44px; height: 44px; border: none; background: transparent; cursor: pointer; flex-direction: column; align-items: center; justify-content: center; gap: 5px; }
.nav-toggle span { width: 24px; height: 2px; background: currentColor; color: var(--ink-900); transition: transform 220ms var(--ease-out), opacity 220ms var(--ease-out); }
.site-header:not(.scrolled) .nav-toggle span { background: #fff; }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  position: relative; overflow: hidden;
  min-height: 100svh;
  display: flex; align-items: center;
  padding: 140px 0 80px;
  background: radial-gradient(120% 120% at 15% 10%, #163f6b 0%, var(--navy-800) 45%, var(--navy-900) 100%);
  color: #fff;
}
.hero-bg { position: absolute; inset: 0; z-index: 0; overflow: hidden; }
.hero-glow { position: absolute; border-radius: 50%; filter: blur(70px); opacity: 0.55; }
.hero-glow-1 { width: 420px; height: 420px; background: var(--cyan-400); top: -120px; right: -80px; opacity: 0.25; }
.hero-glow-2 { width: 320px; height: 320px; background: var(--navy-600); bottom: -100px; left: 10%; opacity: 0.35; }

.frost-particles { position: absolute; inset: 0; }
.frost-particles span {
  position: absolute; bottom: -10px; border-radius: 50%;
  background: rgba(216,245,250,0.55);
  animation: rise linear infinite;
}
@keyframes rise {
  0% { transform: translateY(0) translateX(0); opacity: 0; }
  10% { opacity: 0.8; }
  90% { opacity: 0.5; }
  100% { transform: translateY(-110vh) translateX(20px); opacity: 0; }
}

.hero-inner { position: relative; z-index: 1; display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 40px; align-items: center; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--font-display); font-size: 0.82rem; font-weight: 600; letter-spacing: 0.04em;
  color: var(--cyan-300); background: rgba(27,199,224,0.12); border: 1px solid rgba(27,199,224,0.35);
  padding: 8px 16px; border-radius: 100px; margin: 0 0 22px;
}
.eyebrow-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--cyan-300); box-shadow: 0 0 0 4px rgba(94,227,245,0.25); }

.hero h1 { color: #fff; margin-bottom: 20px; }
.hero-lead { color: rgba(255,255,255,0.78); font-size: 1.08rem; max-width: 560px; }
.hero-lead strong { color: var(--cyan-300); }

.hero-cta { display: flex; gap: 16px; flex-wrap: wrap; margin: 28px 0 40px; }

.hero-trust { display: flex; flex-wrap: wrap; gap: 34px; }
.hero-trust li { display: flex; flex-direction: column; }
.hero-trust strong { font-family: var(--font-display); font-size: 1.5rem; color: #fff; }
.hero-trust span { font-size: 0.82rem; color: rgba(255,255,255,0.6); }

.hero-visual { position: relative; display: flex; justify-content: center; }
.tank-illustration { width: 100%; max-width: 380px; filter: drop-shadow(0 30px 60px rgba(0,0,0,0.35)); }
.vapor-wisp path { animation: wisp 5s ease-in-out infinite; }
.vapor-wisp path:nth-child(2) { animation-delay: 0.6s; }
.vapor-wisp path:nth-child(3) { animation-delay: 1.2s; }
@keyframes wisp {
  0%, 100% { transform: translateY(0); opacity: 0.6; }
  50% { transform: translateY(-8px); opacity: 0.9; }
}

.hero-scroll-cue { position: absolute; bottom: 28px; left: 50%; transform: translateX(-50%); z-index: 1; }
.hero-scroll-cue span { display: block; width: 26px; height: 42px; border: 2px solid rgba(255,255,255,0.4); border-radius: 100px; position: relative; }
.hero-scroll-cue span::before {
  content: ""; position: absolute; top: 8px; left: 50%; width: 4px; height: 8px; background: var(--cyan-300);
  border-radius: 4px; transform: translateX(-50%); animation: scrollcue 1.8s ease-in-out infinite;
}
@keyframes scrollcue { 0% { opacity: 1; top: 8px; } 100% { opacity: 0; top: 22px; } }

/* ==========================================================================
   Brand strip
   ========================================================================== */
.brand-strip { background: var(--frost-100); border-bottom: 1px solid #dcebf1; }
.brand-strip-inner { padding: 16px 24px; text-align: center; }
.brand-strip-inner p { margin: 0; font-size: 0.9rem; color: var(--slate-600); }
.brand-strip-inner a { color: var(--navy-700); font-weight: 600; }
.brand-strip-inner a:hover { text-decoration: underline; }

/* ==========================================================================
   Sections
   ========================================================================== */
.section { padding: 110px 0; }
.section-alt { background: var(--frost-100); }
.section-dark { background: radial-gradient(120% 140% at 85% 0%, #14406f 0%, var(--navy-800) 45%, var(--navy-900) 100%); color: #fff; }

.section-head { max-width: 680px; margin: 0 auto 56px; text-align: center; }
.section-tag {
  font-family: var(--font-display); font-weight: 600; font-size: 0.82rem; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--navy-700); margin-bottom: 12px;
}
.section-tag-light { color: var(--cyan-300); }
.section-lead { font-size: 1.05rem; }
.section-lead-light { color: rgba(255,255,255,0.75); }
.section-dark h1, .section-dark h2, .section-dark h3, .section-dark h4 { color: #fff; }

/* reveal-on-scroll */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 700ms var(--ease-out), transform 700ms var(--ease-out); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }

/* ==========================================================================
   Feature cards
   ========================================================================== */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px; }
.feature-card {
  background: #fff; border: 1px solid #E2ECF1; border-radius: var(--radius-md);
  padding: 32px 28px; transition: transform 260ms var(--ease-out), box-shadow 260ms var(--ease-out), border-color 260ms var(--ease-out);
}
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-soft); border-color: rgba(27,199,224,0.4); }
.feature-icon {
  width: 54px; height: 54px; border-radius: 14px; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, rgba(18,77,141,0.1), rgba(27,199,224,0.15)); color: var(--navy-700); margin-bottom: 20px;
}
.feature-card h3 { margin-bottom: 8px; }
.feature-card p { margin: 0; font-size: 0.95rem; }

/* ==========================================================================
   Use grid (application areas)
   ========================================================================== */
.use-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 20px; }
.use-item {
  text-align: center; background: #fff; border-radius: var(--radius-md); padding: 30px 18px;
  border: 1px solid #E2ECF1; transition: transform 260ms var(--ease-out), box-shadow 260ms var(--ease-out);
}
.use-item:hover { transform: translateY(-4px); box-shadow: var(--shadow-soft); }
.use-item svg { color: var(--cyan-400); margin-bottom: 14px; }
.use-item h3 { font-size: 1rem; margin-bottom: 6px; }
.use-item p { font-size: 0.88rem; margin: 0; }

/* ==========================================================================
   Process
   ========================================================================== */
.process-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 26px; position: relative; }
.process-grid::before {
  content: ""; position: absolute; top: 26px; left: 12%; right: 12%; height: 2px;
  background: repeating-linear-gradient(90deg, var(--navy-700) 0 10px, transparent 10px 18px);
  opacity: 0.3; z-index: 0;
}
.process-step { position: relative; z-index: 1; background: #fff; border-radius: var(--radius-md); padding: 30px 24px; border: 1px solid #E2ECF1; }
.process-number {
  font-family: var(--font-display); font-weight: 700; font-size: 1.3rem; color: #fff;
  width: 52px; height: 52px; border-radius: 50%; display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, var(--navy-700), var(--cyan-400)); margin-bottom: 18px;
  box-shadow: 0 10px 24px -10px rgba(18,77,141,0.5);
}
.process-step h3 { margin-bottom: 8px; }
.process-step p { font-size: 0.92rem; margin: 0; }

/* ==========================================================================
   Why us
   ========================================================================== */
.why-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center; }
.why-copy .btn { margin-top: 10px; }
.why-list { display: flex; flex-direction: column; gap: 22px; }
.why-list li { display: flex; gap: 16px; align-items: flex-start; }
.why-list svg { color: var(--cyan-400); flex-shrink: 0; margin-top: 3px; }
.why-list strong { display: block; color: #fff; font-family: var(--font-display); font-size: 1.02rem; margin-bottom: 2px; }
.why-list span { color: rgba(255,255,255,0.65); font-size: 0.92rem; }

/* ==========================================================================
   Coverage
   ========================================================================== */
.coverage-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 50px; align-items: center; }
.coverage-copy { text-align: left; margin: 0; max-width: none; }
.coverage-stats { display: flex; gap: 34px; margin-top: 28px; }
.coverage-stats li { display: flex; flex-direction: column; }
.coverage-stats strong { font-family: var(--font-display); font-size: 1.6rem; color: var(--navy-700); }
.coverage-stats span { font-size: 0.82rem; color: var(--slate-600); }
.coverage-map { background: #fff; border-radius: var(--radius-lg); border: 1px solid #E2ECF1; padding: 20px; box-shadow: var(--shadow-soft); }
.map-svg { width: 100%; height: auto; }
.map-label { font-family: var(--font-body); font-size: 9px; fill: var(--slate-600); }
.map-pulse .city-pulse { animation: pulse 2.6s ease-out infinite; }
@keyframes pulse { 0% { transform: scale(0.6); opacity: 0.5; } 100% { transform: scale(1.6); opacity: 0; } }

/* ==========================================================================
   FAQ
   ========================================================================== */
.faq-list { max-width: 760px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }
.faq-item { background: #fff; border: 1px solid #E2ECF1; border-radius: var(--radius-md); overflow: hidden; }
.faq-question {
  width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 16px;
  background: none; border: none; text-align: left; padding: 22px 26px; cursor: pointer;
  font-family: var(--font-display); font-weight: 600; font-size: 1rem; color: var(--navy-900);
}
.faq-question svg { flex-shrink: 0; color: var(--navy-700); transition: transform 260ms var(--ease-out); }
.faq-item.is-open .faq-question svg { transform: rotate(45deg); color: var(--cyan-400); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 320ms var(--ease-out); }
.faq-answer p { padding: 0 26px 22px; margin: 0; font-size: 0.95rem; }
.faq-item.is-open .faq-answer { max-height: 320px; }

/* ==========================================================================
   Contact / quote form
   ========================================================================== */
.contact-grid { display: grid; grid-template-columns: 0.85fr 1.15fr; gap: 60px; align-items: start; }
.contact-details { display: flex; flex-direction: column; gap: 16px; margin: 28px 0; }
.contact-details li { display: flex; align-items: center; gap: 12px; color: rgba(255,255,255,0.85); }
.contact-details svg { color: var(--cyan-300); flex-shrink: 0; }
.contact-details a:hover { color: var(--cyan-300); }
.contact-parent { font-size: 0.88rem; color: rgba(255,255,255,0.55); }
.contact-parent a { color: var(--cyan-300); font-weight: 600; }

.quote-form {
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.14); backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px); border-radius: var(--radius-lg); padding: 36px; box-shadow: var(--shadow-glow);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.form-field { margin-bottom: 18px; }
.form-field label { display: block; font-size: 0.85rem; font-weight: 600; color: rgba(255,255,255,0.85); margin-bottom: 7px; }
.form-field input, .form-field textarea {
  width: 100%; padding: 13px 16px; border-radius: var(--radius-sm); border: 1.5px solid rgba(255,255,255,0.18);
  background: rgba(8,27,48,0.35); color: #fff; font-family: var(--font-body); font-size: 0.95rem;
  transition: border-color 200ms var(--ease-out), background 200ms var(--ease-out);
}
.form-field input::placeholder, .form-field textarea::placeholder { color: rgba(255,255,255,0.35); }
.form-field input:focus, .form-field textarea:focus { border-color: var(--cyan-400); background: rgba(8,27,48,0.55); outline: none; }
.form-field textarea { resize: vertical; min-height: 100px; }
.form-field.has-error input, .form-field.has-error textarea { border-color: #ff8a80; }
.form-error { display: block; font-size: 0.78rem; color: #ff8a80; margin-top: 6px; min-height: 1em; }

.form-checkbox { display: flex; align-items: flex-start; gap: 10px; }
.form-checkbox input { width: 18px; height: 18px; margin-top: 2px; accent-color: var(--cyan-400); flex-shrink: 0; }
.form-checkbox label { margin: 0; font-size: 0.85rem; font-weight: 400; color: rgba(255,255,255,0.7); }

.hp-field { position: absolute !important; left: -9999px !important; width: 1px; height: 1px; opacity: 0; }

.btn-spinner {
  width: 18px; height: 18px; border-radius: 50%; border: 2.5px solid rgba(255,255,255,0.4); border-top-color: #fff;
  display: none; animation: spin 0.7s linear infinite;
}
.quote-form.is-loading .btn-label { opacity: 0.6; }
.quote-form.is-loading .btn-spinner { display: inline-block; }
@keyframes spin { to { transform: rotate(360deg); } }

.form-status { margin: 14px 0 0; font-size: 0.9rem; min-height: 1.2em; }
.form-status.success { color: var(--cyan-300); }
.form-status.error { color: #ff8a80; }

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer { background: var(--navy-900); color: rgba(255,255,255,0.7); padding: 60px 0 30px; }
.footer-inner { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 40px; padding-bottom: 34px; border-bottom: 1px solid rgba(255,255,255,0.1); }
.footer-brand img { display: block; margin-bottom: 14px; }
.footer-brand p { font-size: 0.88rem; max-width: 320px; }
.footer-nav { display: flex; flex-direction: column; gap: 12px; }
.footer-nav a:hover { color: var(--cyan-300); }
.footer-legal p { font-size: 0.85rem; margin: 0 0 8px; }
.footer-legal a:hover { color: var(--cyan-300); }
.footer-inner + .container p { padding-top: 20px; }
.site-footer .container > p { text-align: center; font-size: 0.8rem; padding-top: 20px; }

/* ==========================================================================
   Mobile call FAB
   ========================================================================== */
.mobile-call-fab {
  display: none; position: fixed; bottom: 20px; right: 20px; z-index: 90;
  width: 56px; height: 56px; border-radius: 50%; background: var(--navy-700); color: #fff;
  align-items: center; justify-content: center; box-shadow: 0 12px 30px -10px rgba(18,77,141,0.6);
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 1024px) {
  .card-grid { grid-template-columns: repeat(2, 1fr); }
  .use-grid { grid-template-columns: repeat(4, 1fr); }
  .process-grid { grid-template-columns: repeat(2, 1fr); }
  .process-grid::before { display: none; }
  .why-grid, .coverage-grid, .contact-grid { grid-template-columns: 1fr; }
  .hero-inner { grid-template-columns: 1fr; text-align: center; }
  .hero-lead { margin-left: auto; margin-right: auto; }
  .hero-cta, .hero-trust { justify-content: center; }
  .hero-visual { max-width: 320px; margin: 0 auto; }
  .coverage-copy { text-align: center; }
  .coverage-stats { justify-content: center; }
}

@media (max-width: 860px) {
  .main-nav { position: fixed; inset: 0 0 0 auto; width: min(320px, 82vw); background: var(--navy-900); padding: 100px 32px 40px; transform: translateX(100%); transition: transform 320ms var(--ease-out); z-index: 99; }
  .main-nav.is-open { transform: translateX(0); }
  .main-nav ul { flex-direction: column; gap: 22px; }
  .main-nav a, .site-header:not(.scrolled) .main-nav a { color: #fff; font-size: 1.05rem; }
  .header-phone { display: none; }
  .nav-toggle { display: flex; }
  .header-actions .btn-sm { display: none; }
  .mobile-call-fab { display: flex; }

  .use-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr; text-align: center; }
  .footer-brand img { margin: 0 auto 14px; }
  .footer-nav { align-items: center; }
}

@media (max-width: 620px) {
  .section { padding: 76px 0; }
  .hero { padding: 120px 0 60px; }
  .card-grid, .use-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .quote-form { padding: 26px 20px; }
  .hero-trust { gap: 22px; }
}

.nav-toggle.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.is-open span:nth-child(2) { opacity: 0; }
.nav-toggle.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }