:root {
    --bg: #0a0e14;
    --surface: #111720;
    --border: #1e2d3d;
    --accent: #00d4ff;
    --accent2: #ff6b00;
    --green: #00ff88;
    --yellow: #ffd600;
    --red: #ff3b3b;
    --text: #c8d8e8;
    --muted: #5a7a8a;
    --white: #f0f8ff;
  }

  * { margin: 0; padding: 0; box-sizing: border-box; }

  html { scroll-behavior: smooth; }

  /* ── 1. ÚPRAVA PRO BODY: Nastavení Flexboxu pro tlačení patičky dolů ── */
  body {
    background: var(--bg);
    color: var(--text);
    font-family: 'DM Sans', sans-serif;
    font-weight: 400;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh; /* Roztáhne body na celou výšku obrazovky */
  }

  /* ── 2. ÚPRAVA PRO MAIN WRAPPER: Vyplní veškeré volné místo ── */
  .content-wrapper {
    flex: 1;
    position: relative;
    z-index: 1;
  }

  /* ── GRID OVERLAY (Nyní fixovaný na pozadí body) ── */
  body::before {
    content: '';
    position: fixed;
    inset: 0;
    background-image:
      linear-gradient(rgba(0,212,255,.03) 1px, transparent 1px),
      linear-gradient(90deg, rgba(0,212,255,.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
  }

  /* ── NAV ── */
  nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 40px;
    background: rgba(10,14,20,.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
  }

  .logo {
    font-family: 'Bebas Neue', sans-serif;
    font-size: 26px;
    letter-spacing: 3px;
    color: var(--white);
  }
  .logo span { color: var(--accent); }

  nav a {
    color: var(--muted);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    letter-spacing: .5px;
    transition: color .2s;
  }
  nav a:hover { color: var(--accent); }

  .nav-links { display: flex; gap: 32px; }

  .nav-cta {
    background: var(--accent);
    color: var(--bg) !important;
    padding: 8px 20px;
    border-radius: 4px;
    font-weight: 600 !important;
  }
  .nav-cta:hover { background: #33ddff !important; color: var(--bg) !important; }

  /* ── HERO ── */
  .hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px 40px 80px;
    max-width: 1200px;
    margin: 0 auto;
    gap: 60px;
  }
  .seda-kapka {
    filter: grayscale(100%);
    opacity: 0.8;
    display: inline-block;
  }

  .hero-text { flex: 1; z-index: 1; }

  .hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(0,212,255,.1);
    border: 1px solid rgba(0,212,255,.3);
    padding: 6px 14px;
    border-radius: 100px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 24px;
    animation: fadeUp .6s ease both;
  }

  .hero-badge::before {
    content: '';
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
    animation: pulse 2s infinite;
  }

  @keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: .4; transform: scale(.8); }
  }

  h1 {
    font-family: 'Bebas Neue', sans-serif;
    font-size: clamp(54px, 7vw, 96px);
    line-height: .95;
    letter-spacing: 2px;
    color: var(--white);
    animation: fadeUp .6s .1s ease both;
  }

  h1 em {
    font-style: normal;
    color: var(--accent);
    display: block;
  }

  .hero-sub {
    margin-top: 24px;
    font-size: 18px;
    line-height: 1.6;
    color: var(--muted);
    max-width: 480px;
    animation: fadeUp .6s .2s ease both;
  }

  .hero-actions {
    display: flex;
    gap: 16px;
    margin-top: 40px;
    flex-wrap: wrap;
    animation: fadeUp .6s .3s ease both;
  }

  .btn-primary {
    background: var(--accent);
    color: var(--bg);
    padding: 14px 32px;
    border-radius: 4px;
    font-weight: 700;
    font-size: 16px;
    text-decoration: none;
    transition: all .2s;
    display: inline-flex;
    align-items: center;
    gap: 8px;
  }
  .btn-primary:hover { background: #33ddff; transform: translateY(-2px); }

  .btn-secondary {
    border: 1px solid var(--border);
    color: var(--text);
    padding: 14px 32px;
    border-radius: 4px;
    font-weight: 500;
    font-size: 16px;
    text-decoration: none;
    transition: all .2s;
  }
  .btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

  /* ── TANK VISUALIZER ── */
  .hero-visual {
    flex: 0 0 340px;
    z-index: 1;
    animation: fadeUp .6s .2s ease both;
  }

  .tank-wrap {
    position: relative;
    width: 100%;
    aspect-ratio: 1 / 1.4;
  }

  .tank-container {
    width: 160px;
    height: 280px;
    border: 2px solid var(--border);
    border-radius: 12px;
    position: relative;
    overflow: hidden;
    margin: 0 auto;
    background: var(--surface);
    box-shadow: 0 0 40px rgba(0,212,255,.08), inset 0 0 20px rgba(0,0,0,.5);
  }

  .tank-fill {
    position: absolute;
    bottom: 0; left: 0; right: 0;
    background: linear-gradient(180deg, rgba(0,212,255,.6) 0%, rgba(0,100,180,.8) 100%);
    animation: fillUp 3s ease-in-out forwards, wavey 4s 3s ease-in-out infinite;
    border-radius: 0 0 10px 10px;
  }

  @keyframes fillUp {
    from { height: 5%; }
    to { height: 73%; }
  }
  @keyframes wavey {
    0%, 100% { clip-path: polygon(0 5%, 25% 0%, 50% 5%, 75% 0%, 100% 5%, 100% 100%, 0 100%); }
    50% { clip-path: polygon(0 0%, 25% 5%, 50% 0%, 75% 5%, 100% 0%, 100% 100%, 0 100%); }
  }

  .tank-label {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-family: 'Bebas Neue', sans-serif;
    font-size: 48px;
    color: var(--white);
    text-shadow: 0 2px 8px rgba(0,0,0,.8);
    z-index: 2;
  }

  .led-strip {
    position: absolute;
    right: -28px;
    top: 0; bottom: 0;
    width: 16px;
    display: flex;
    flex-direction: column-reverse;
    gap: 3px;
  }

  .led {
    flex: 1;
    border-radius: 2px;
    background: var(--border);
  }

  .led:nth-child(-n+15) {
    background: var(--barva-led);
    box-shadow: 0 0 8px var(--barva-led);
  }

  .led:nth-child(-n+6) { --barva-led: var(--red); }
  .led:nth-child(n+7):nth-child(-n+12) { --barva-led: var(--yellow); }
  .led:nth-child(n+13):nth-child(-n+15) { --barva-led: var(--green); }

  .tank-pipe {
    position: absolute;
    left: 50%;
    bottom: -30px;
    transform: translateX(-50%);
    width: 8px;
    height: 34px;
    background: var(--border);
    border-radius: 0 0 4px 4px;
  }

  .wireless-signal {
    position: absolute;
    top: 20px;
    right: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
  }

  .signal-bar {
    width: 4px;
    background: var(--accent);
    border-radius: 2px;
    opacity: .3;
  }
  .signal-bar:nth-child(1) { height: 8px; opacity: 1; animation: signalPulse 1.5s .0s infinite; }
  .signal-bar:nth-child(2) { height: 14px; opacity: .7; animation: signalPulse 1.5s .2s infinite; }
  .signal-bar:nth-child(3) { height: 20px; opacity: .4; animation: signalPulse 1.5s .4s infinite; }
  .signal-bar:nth-child(4) { height: 26px; animation: signalPulse 1.5s .6s infinite; }

  @keyframes signalPulse {
    0%, 100% { opacity: .2; }
    50% { opacity: 1; }
  }

  /* ── STATS ── */
  .stats-bar {
    background: var(--surface);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    padding: 32px 40px;
  }
  .stats-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-around;
    gap: 40px;
    flex-wrap: wrap;
  }
  .stat { text-align: center; }
  .stat-number {
    font-family: 'Bebas Neue', sans-serif;
    font-size: 48px;
    color: var(--accent);
    line-height: 1;
  }
  .stat-label {
    font-size: 13px;
    color: var(--muted);
    margin-top: 4px;
    letter-spacing: .5px;
  }

  /* ── SECTIONS ── */
  section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 40px;
    position: relative;
    z-index: 1;
  }

  .section-label {
    font-family: 'DM Mono', monospace;
    font-size: 12px;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 16px;
  }

  h2 {
    font-family: 'Bebas Neue', sans-serif;
    font-size: clamp(36px, 5vw, 60px);
    letter-spacing: 2px;
    color: var(--white);
    line-height: 1;
    margin-bottom: 16px;
  }

  .section-sub {
    font-size: 17px;
    color: var(--muted);
    max-width: 560px;
    line-height: 1.7;
    margin-bottom: 60px;
  }

  /* ── HOW IT WORKS ── */
  .steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2px;
    background: var(--border);
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
  }

  .step {
    background: var(--surface);
    padding: 36px 28px;
    position: relative;
    transition: background .2s;
  }
  .step:hover { background: #161f2a; }

  .step-num {
    font-family: 'Bebas Neue', sans-serif;
    font-size: 64px;
    color: rgba(0,212,255,.08);
    line-height: 1;
    position: absolute;
    top: 16px; right: 20px;
  }

  .step-icon {
    width: 44px;
    height: 44px;
    background: rgba(0,212,255,.1);
    border: 1px solid rgba(0,212,255,.2);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    margin-bottom: 20px;
  }

  .step h3 {
    font-weight: 600;
    font-size: 16px;
    color: var(--white);
    margin-bottom: 10px;
  }

  .step p {
    font-size: 14px;
    color: var(--muted);
    line-height: 1.6;
  }

  /* ── FEATURES ── */
  .features-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }

  .feature-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 32px;
    transition: border-color .2s, transform .2s;
    position: relative;
    overflow: hidden;
  }
  .feature-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent), transparent);
    opacity: 0;
    transition: opacity .2s;
  }
  .feature-card:hover { border-color: rgba(0,212,255,.3); transform: translateY(-3px); }
  .feature-card:hover::before { opacity: 1; }

  .feature-icon { font-size: 32px; margin-bottom: 16px; }

  .feature-card h3 {
    font-weight: 600;
    font-size: 18px;
    color: var(--white);
    margin-bottom: 10px;
  }

  .feature-card p {
    font-size: 14px;
    color: var(--muted);
    line-height: 1.7;
  }

  /* ── USE CASES ── */
  .use-cases {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
  }

  .use-case {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 28px 20px;
    text-align: center;
    transition: border-color .2s;
  }
  .use-case:hover { border-color: var(--accent); }

  .use-case-icon { font-size: 36px; margin-bottom: 12px; }
  .use-case h3 { font-size: 15px; font-weight: 600; color: var(--white); }

  /* ── SPECS ── */
  .specs-table {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    width: 100%;
  }

  .spec-row {
    display: flex;
    border-bottom: 1px solid var(--border);
  }
  .spec-row:last-child { border-bottom: none; }

  .spec-key {
    flex: 0 0 260px;
    padding: 16px 24px;
    color: var(--muted);
    border-right: 1px solid var(--border);
    font-family: 'DM Mono', monospace;
    font-size: 13px;
  }

  .spec-val {
    padding: 16px 24px;
    font-size: 14px;
    color: var(--white);
    font-weight: 500;
  }

  /* ── PRICING ── */
  .pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
    margin-bottom: 32px;
  }

  .price-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 28px;
    transition: border-color .2s;
  }
  .price-card.featured {
    border-color: var(--accent);
    position: relative;
  }
  
  .price-card.featured::before {
     content: 'NEJPRODÁVANĚJŠÍ';
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--accent);
    color: var(--bg);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 1px;
    padding: 4px 12px;
    border-radius: 100px;
    white-space: nowrap;
  }

  .price-card h3 {
    font-size: 14px;
    color: var(--muted);
    font-weight: 500;
    margin-bottom: 12px;
    letter-spacing: .5px;
  }

  .price-amount {
    font-family: 'Bebas Neue', sans-serif;
    font-size: 42px;
    color: var(--white);
    line-height: 1;
  }
  .price-amount span {
    font-family: 'DM Sans', sans-serif;
    font-size: 18px;
    color: var(--muted);
  }

  .price-desc {
    font-size: 13px;
    color: var(--muted);
    margin-top: 8px;
    line-height: 1.5;
  }

  .price-includes {
    margin-top: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
  }

  .price-item {
    font-size: 13px;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 8px;
  }
  .price-item::before {
    content: '✓';
    color: var(--green);
    font-weight: 700;
    flex-shrink: 0;
  }

  .total-box {
    background: rgba(0,212,255,.07);
    border: 1px solid rgba(0,212,255,.2);
    border-radius: 8px;
    padding: 24px 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
  }

  .total-label { font-size: 16px; color: var(--muted); }
  .total-price {
    font-family: 'Bebas Neue', sans-serif;
    font-size: 52px;
    color: var(--accent);
    line-height: 1;
  }
  .total-note { font-size: 13px; color: var(--muted); }

  /* ── CONTACT ── */
  .contact-section {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 80px 40px;
  }

  .contact-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: start;
  }

  .contact-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
  }

  .form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
  }

  label {
    font-size: 13px;
    font-weight: 500;
    color: var(--muted);
    letter-spacing: .5px;
  }

  input, textarea, select {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 12px 16px;
    color: var(--white);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    outline: none;
    transition: border-color .2s;
    width: 100%;
  }
  input:focus, textarea:focus, select:focus { border-color: var(--accent); }
  textarea { height: 120px; resize: vertical; }
  select option { background: var(--bg); }

  .submit-btn {
    background: var(--accent);
    color: var(--bg);
    border: none;
    padding: 14px 32px;
    border-radius: 4px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: all .2s;
    width: 100%;
  }
  .submit-btn:hover { background: #33ddff; transform: translateY(-2px); }

  .contact-info { display: flex; flex-direction: column; gap: 32px; }

  .contact-item h4 {
    font-size: 13px;
    color: var(--muted);
    letter-spacing: 1px;
    text-transform: uppercase;
    margin-bottom: 8px;
  }
  .contact-item a, .contact-item p {
    font-size: 17px;
    color: var(--white);
    text-decoration: none;
    font-weight: 500;
  }
  .contact-item a:hover { color: var(--accent); }

  /* ── FOOTER ── */
  footer {
    border-top: 1px solid var(--border);
    padding: 24px 40px;
    text-align: center;
    font-size: 13px;
    color: var(--muted);
    z-index: 1;

  }

  /* ── ANIMATIONS ── */
  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
  }

  /* ── RESPONSIVE ── */
  @media (max-width: 768px) {
    nav { padding: 14px 20px; }
    .nav-links { display: none; }
    .hero { flex-direction: column; padding: 100px 20px 60px; gap: 40px; }
    .hero-visual { flex: none; width: 100%; }
    section { padding: 60px 20px; }
    .features-grid { grid-template-columns: 1fr; }
    .contact-inner { grid-template-columns: 1fr; gap: 40px; }
    .stats-bar { padding: 24px 20px; }
    .spec-key { flex: 0 0 160px; }
    .total-box { flex-direction: column; text-align: center; }
  }

  /* .obrazekM1 { 
  position: absolute;
  top: -350px;      
  left: auto;       
  width: 250px;
  height: auto;
}
*/

/* ── RESPONSIVNÍ ROZVRŽENÍ SEKCE JAK TO FUNGUJE ── */

/* ── FINÁLNÍ RESPONZIVNÍ ROZVRŽENÍ SEKCE JAK TO FUNGUJE ── */

/* ── FINÁLNÍ RESPONZIVNÍ ROZVRŽENÍ SEKCE JAK TO FUNGUJE ── */

/* Společný kontejner pro kroky a obrázek */
.how-it-works-content {
  display: flex;
  flex-direction: column; /* Na mobilu řadíme pod sebe */
  gap: 24px;
  width: 100%;
  margin-top: 20px;       /* Na mobilu jemná mezera pod textem */
}

.steps-side {
  width: 100%;
}

.image-side {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Obrázek: Na mobilu kompaktní (280px) */
.obrazekM1 {
  position: static !important; 
  width: 100%;
  max-width: 280px; 
  height: auto;
  object-fit: cover;
  border-radius: 8px;
  border: 1px solid var(--border);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

/* Nastavení pro počítače a větší obrazovky (od šířky 992px výše) */
@media (min-width: 992px) {
  .how-it-works-content {
    flex-direction: row;   /* Text a obrázek vedle sebe */
    align-items: flex-start;
    gap: 48px;
    margin-top: -30px;     /* ZÁPORNÝ MARGIN: Vytáhne kroky i obrázek výrazně NAHORU k nadpisu */
  }

  .steps-side {
    flex: 1;
  }

  .image-side {
    flex: 0 0 340px; 
    position: sticky;
    top: 70px;             /* VYŠŠÍ POZICE: Obrázek bude při skrolování držet blíž k hornímu okraji */
  }

  .obrazekM1 {
    max-width: 100%;
  }
}



/* Styl pro otevřené menu a rozestupy */
details[open] .dropdown-links {
  display: flex;
  flex-direction: column;
  gap: 16px;              /* Mezera mezi odkazy */
  padding: 16px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  position: absolute;
  right: 40px;
  top: 60px;
  min-width: 200px;
  z-index: 1000;
}

.dropdown-links a {
  display: block;
  padding: 4px 0;
  color: var(--text);
  text-decoration: none;
}

.dropdown-links a:hover {
  color: var(--accent);
}