/* ============================================================
   Zuid PetroTech — Stylesheet
   Theme inspired by the Production System Optimisation infographic
   ============================================================ */

:root {
  --bg: #0a1428;
  --bg-alt: #0e1c38;
  --panel: #12213f;
  --panel-2: #16294c;
  --text: #e8eef7;
  --muted: #9fb0c9;
  --border: rgba(255, 255, 255, 0.08);

  --green: #7cc243;
  --gold: #f0a83c;
  --blue: #3a9bdc;
  --orange: #e6772e;
  --purple: #8b6fc9;

  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.45);
  --max: 1180px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 clamp(1rem, 4vw, 2.5rem);
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* Accent helpers */
.accent-gold, .accent-gold-text { color: var(--gold); }
.accent-green { color: var(--green); }
.accent-blue { color: var(--blue); }

/* ============================================================
   HEADER / NAV
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 20, 40, 0.82);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}
.brand-mark { color: var(--green); display: grid; place-items: center; }
.brand-text { font-size: 1.05rem; }
.brand-text strong { color: var(--gold); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
}
.nav-links a {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s var(--ease);
}
.nav-links a:hover { color: var(--text); }

.nav-cta {
  background: var(--green);
  color: #06210a !important;
  padding: 0.5rem 1.1rem;
  border-radius: 999px;
  font-weight: 700 !important;
}
.nav-cta:hover { filter: brightness(1.08); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 6px;
}
.nav-toggle span {
  width: 26px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease);
}
.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: clamp(4.5rem, 12vw, 9rem) 0;
  background:
    radial-gradient(1200px 500px at 80% -10%, rgba(58, 155, 220, 0.22), transparent 60%),
    radial-gradient(900px 500px at 0% 20%, rgba(124, 194, 67, 0.14), transparent 55%),
    linear-gradient(160deg, #0a1428 0%, #0d1e3c 100%);
  overflow: hidden;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(115deg, rgba(255,255,255,0.02) 0 2px, transparent 2px 26px);
  pointer-events: none;
}
.hero-inner { position: relative; max-width: 860px; }

.hero-kicker {
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--blue);
  margin-bottom: 1.1rem;
}
.hero-title {
  font-size: clamp(2.2rem, 6vw, 4.2rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.02em;
}
.hero-sub {
  margin-top: 1.3rem;
  font-size: clamp(1rem, 2.4vw, 1.3rem);
  color: var(--muted);
  font-weight: 500;
}
.hero-actions {
  margin-top: 2.2rem;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 1.7rem;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.2s var(--ease), filter 0.2s var(--ease), background 0.2s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn-primary { background: var(--green); color: #06210a; }
.btn-primary:hover { filter: brightness(1.08); }
.btn-ghost { border-color: rgba(255,255,255,0.25); color: var(--text); }
.btn-ghost:hover { background: rgba(255,255,255,0.06); }

/* ============================================================
   VISION
   ============================================================ */
.vision {
  background: linear-gradient(90deg, rgba(124,194,67,0.10), rgba(58,155,220,0.10));
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.vision-inner {
  display: flex;
  align-items: center;
  gap: 1.4rem;
  padding: 2.2rem clamp(1rem, 4vw, 2.5rem);
}
.vision-icon {
  flex: 0 0 auto;
  width: 62px;
  height: 62px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: var(--green);
  background: rgba(124,194,67,0.12);
  border: 1px solid rgba(124,194,67,0.3);
}
.vision-title { font-size: 1.2rem; color: var(--green); letter-spacing: 0.04em; text-transform: uppercase; }
.vision-text { color: var(--text); font-size: clamp(1rem, 2.2vw, 1.25rem); font-weight: 500; }

/* ============================================================
   SECTIONS
   ============================================================ */
.section { padding: clamp(3.5rem, 8vw, 6rem) 0; }
.section-alt { background: var(--bg-alt); }

.section-head { text-align: center; max-width: 720px; margin: 0 auto clamp(2.2rem, 5vw, 3.4rem); }
.section-title {
  font-size: clamp(1.7rem, 4vw, 2.7rem);
  font-weight: 800;
  letter-spacing: -0.01em;
}
.section-lead { margin-top: 0.8rem; color: var(--muted); font-size: clamp(1rem, 2.2vw, 1.2rem); }

/* ============================================================
   PRODUCTION SYSTEM GRID
   ============================================================ */
.system-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.2rem;
}
.sys-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.8rem 1.4rem;
  text-align: center;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), border-color 0.25s var(--ease);
  border-top: 3px solid var(--border);
}
.sys-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.sys-card[data-accent="green"]  { border-top-color: var(--green); }
.sys-card[data-accent="blue"]   { border-top-color: var(--blue); }
.sys-card[data-accent="orange"] { border-top-color: var(--orange); }
.sys-card[data-accent="gold"]   { border-top-color: var(--gold); }
.sys-card[data-accent="purple"] { border-top-color: var(--purple); }
.sys-icon { font-size: 2.2rem; margin-bottom: 0.7rem; }
.sys-card h3 { font-size: 1.1rem; margin-bottom: 0.25rem; }
.sys-card p { color: var(--muted); font-size: 0.92rem; }

/* ============================================================
   OPTIMISATION CYCLE
   ============================================================ */
.cycle-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 1.2rem;
}
.cycle-card {
  position: relative;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem 1.4rem 1.5rem;
  overflow: hidden;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}
.cycle-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.cycle-card::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 4px;
  background: linear-gradient(var(--green), var(--blue));
}
.cycle-step {
  font-size: 2.2rem;
  font-weight: 900;
  color: rgba(240,168,60,0.35);
  line-height: 1;
}
.cycle-card h3 { margin-top: 0.4rem; font-size: 1.25rem; color: var(--gold); }
.cycle-card p { color: var(--muted); margin-top: 0.3rem; }

/* ============================================================
   INNOVATION GRID
   ============================================================ */
.innovation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.2rem;
}
.inno-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.7rem;
  transition: transform 0.25s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}
.inno-card:hover {
  transform: translateY(-5px);
  border-color: rgba(58,155,220,0.5);
  box-shadow: var(--shadow);
}
.inno-card h3 { font-size: 1.15rem; margin-bottom: 0.5rem; color: var(--blue); }
.inno-card p { color: var(--muted); }
.inno-card em { color: var(--gold); font-style: italic; }

/* ============================================================
   PRINCIPLES
   ============================================================ */
.principles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 1.2rem;
}
.prin-card {
  text-align: center;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.7rem 1.2rem;
  transition: transform 0.25s var(--ease);
}
.prin-card:hover { transform: translateY(-5px); }
.prin-icon { font-size: 2rem; margin-bottom: 0.6rem; }
.prin-card h3 { font-size: 1.05rem; }
.prin-card p { color: var(--muted); font-size: 0.9rem; }

.principles-banner {
  margin-top: clamp(2.5rem, 5vw, 3.5rem);
  text-align: center;
  font-weight: 900;
  font-size: clamp(1.3rem, 4vw, 2.4rem);
  letter-spacing: -0.01em;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem 1.2rem;
}

/* ============================================================
   CONTACT
   ============================================================ */
.contact { background: linear-gradient(160deg, #0a1428, #0e1f3e); }
.contact-inner { max-width: 700px; margin: 0 auto; text-align: center; }
.contact-form {
  margin-top: 2.4rem;
  text-align: left;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(1.5rem, 4vw, 2.4rem);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.1rem; }
.field { margin-bottom: 1.1rem; display: flex; flex-direction: column; }
.field label { font-size: 0.85rem; font-weight: 600; margin-bottom: 0.4rem; color: var(--muted); }
.field input, .field textarea {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.8rem 0.9rem;
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  transition: border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.field input:focus, .field textarea:focus {
  outline: none;
  border-color: var(--green);
  box-shadow: 0 0 0 3px rgba(124,194,67,0.2);
}
.field textarea { resize: vertical; }
.form-status { margin-top: 0.9rem; font-size: 0.9rem; font-weight: 600; min-height: 1.2em; }
.form-status.ok { color: var(--green); }
.form-status.err { color: #ff7a7a; }

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  background: #071022;
  border-top: 1px solid var(--border);
  padding: 2.4rem 0;
}
.footer-inner { text-align: center; }
.footer-tagline {
  font-weight: 800;
  font-size: clamp(1rem, 2.6vw, 1.4rem);
  letter-spacing: 0.01em;
}
.footer-copy { margin-top: 0.8rem; color: var(--muted); font-size: 0.85rem; }

/* ============================================================
   REVEAL ANIMATION
   ============================================================ */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.6s var(--ease), transform 0.6s var(--ease); }
.reveal.visible { opacity: 1; transform: none; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 820px) {
  .nav-toggle { display: flex; }
  .nav-links {
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s var(--ease);
  }
  .nav-links.open { max-height: 360px; }
  .nav-links li { border-top: 1px solid var(--border); }
  .nav-links a { display: block; padding: 1rem clamp(1rem, 4vw, 2.5rem); }
  .nav-cta { border-radius: 0; text-align: center; }
}

@media (max-width: 560px) {
  .form-row { grid-template-columns: 1fr; }
  .vision-inner { flex-direction: column; text-align: center; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; }
}

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