/* ==========================================================================
   Ravault Energy — stylesheet
   Clean-tech theme. Edit the CSS variables below to re-brand quickly.
   ========================================================================== */

:root {
  --blue-900: #0a2540;
  --blue-800: #0f3d68;
  --blue-600: #1667b1;
  --green-500: #17b978;
  --green-400: #2fd18f;
  --green-600: #0f9a63;
  --ink: #142033;
  --muted: #56637a;
  --line: #e2e8f0;
  --bg: #ffffff;
  --bg-soft: #f5f8fc;
  --bg-dark: #071a2f;
  --white: #ffffff;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(10, 37, 64, 0.08);
  --shadow-lg: 0 20px 50px rgba(10, 37, 64, 0.14);
  --max: 1140px;
  --font: "Segoe UI", system-ui, -apple-system, Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  line-height: 1.65;
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { line-height: 1.2; color: var(--blue-900); margin: 0 0 0.5em; }
h1 { font-size: clamp(2.1rem, 5vw, 3.3rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.7rem, 3.5vw, 2.4rem); letter-spacing: -0.01em; }
h3 { font-size: 1.25rem; }
p { margin: 0 0 1rem; color: var(--muted); }
a { color: var(--blue-600); text-decoration: none; }
img { max-width: 100%; display: block; }

.container { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 20px; }

.section { padding: 84px 0; }
.section--soft { background: var(--bg-soft); }
.section__eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--green-600);
  margin-bottom: 12px;
}
.section__lead { max-width: 720px; font-size: 1.1rem; }
.text-center { text-align: center; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 13px 26px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}
.btn:active { transform: translateY(1px); }
.btn--primary { background: var(--green-500); color: var(--white); box-shadow: var(--shadow); }
.btn--primary:hover { background: var(--green-600); box-shadow: var(--shadow-lg); }
.btn--ghost { background: transparent; color: var(--white); border-color: rgba(255, 255, 255, 0.6); }
.btn--ghost:hover { background: rgba(255, 255, 255, 0.12); }
.btn--outline { background: transparent; color: var(--blue-600); border-color: var(--blue-600); }
.btn--outline:hover { background: var(--blue-600); color: var(--white); }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 1.2rem; color: var(--blue-900); }
.brand__mark { width: 30px; height: 30px; }
.brand span b { color: var(--green-600); }
.nav__links { display: flex; align-items: center; gap: 28px; list-style: none; margin: 0; padding: 0; }
.nav__links a { color: var(--ink); font-weight: 500; }
.nav__links a:hover { color: var(--green-600); }
.nav__toggle {
  display: none; background: none; border: 0; cursor: pointer;
  width: 44px; height: 44px; padding: 10px;
}
.nav__toggle span { display: block; height: 2px; background: var(--blue-900); margin: 5px 0; transition: 0.25s; }

@media (max-width: 860px) {
  .nav__toggle { display: block; }
  .nav__links {
    position: absolute; top: 68px; left: 0; right: 0;
    flex-direction: column; gap: 0;
    background: var(--white); border-bottom: 1px solid var(--line);
    max-height: 0; overflow: hidden; transition: max-height 0.3s ease;
  }
  .nav__links.open { max-height: 360px; }
  .nav__links li { width: 100%; text-align: center; }
  .nav__links a { display: block; padding: 16px; border-top: 1px solid var(--line); }
  .nav__links .btn { margin: 12px auto; }
}

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(160deg, var(--blue-900) 0%, var(--blue-800) 55%, var(--blue-600) 120%);
  color: var(--white);
  padding: 72px 0 84px;
  overflow: hidden;
}
.hero__grid { display: grid; grid-template-columns: 1.05fr 1fr; gap: 48px; align-items: center; }
.hero h1 { color: var(--white); }
.hero p { color: rgba(255, 255, 255, 0.85); font-size: 1.15rem; max-width: 520px; }
.hero__tag {
  display: inline-block; padding: 6px 14px; border-radius: 999px;
  background: rgba(47, 209, 143, 0.18); color: var(--green-400);
  font-weight: 600; font-size: 0.85rem; letter-spacing: 0.04em; margin-bottom: 20px;
}
.hero__cta { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 26px; }
.hero__art { background: rgba(255, 255, 255, 0.06); border: 1px solid rgba(255, 255, 255, 0.12); border-radius: var(--radius); padding: 22px; }

@media (max-width: 860px) {
  .hero__grid { grid-template-columns: 1fr; gap: 28px; }
}

/* ---------- Value chain strip ---------- */
.chain { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 32px; }
.chain__step { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); display: flex; flex-direction: column; }
.chain__media { position: relative; aspect-ratio: 16 / 10; background: var(--bg-soft); }
.chain__media img { width: 100%; height: 100%; object-fit: cover; display: block; }
.chain__fallback { position: absolute; inset: 0; display: none; place-items: center; background: var(--bg-soft); }
.chain__fallback svg { width: 72px; height: 72px; }
.chain__step.no-img .chain__media img { display: none; }
.chain__step.no-img .chain__fallback { display: grid; }
.chain__body { padding: 20px 22px; }
.chain__body h3 { margin-bottom: 6px; }
.chain__body p { margin: 0; font-size: 0.95rem; }
.chain__note { display: inline-block; margin-top: 10px; font-size: 0.78rem; color: var(--muted); font-style: italic; }
@media (max-width: 720px) { .chain { grid-template-columns: 1fr; } }

/* ---------- Feature cards (flow-battery characteristics) ---------- */
.cards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin-top: 36px; }
.card {
  background: var(--white); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 22px; box-shadow: var(--shadow); transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.card__icon {
  width: 52px; height: 52px; border-radius: 12px; display: grid; place-items: center;
  background: rgba(23, 185, 120, 0.12); margin-bottom: 16px;
}
.card__icon svg { width: 28px; height: 28px; }
.card h3 { font-size: 1.1rem; margin-bottom: 6px; }
.card p { margin: 0; font-size: 0.95rem; }
@media (max-width: 980px) { .cards { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 520px) { .cards { grid-template-columns: 1fr; } }

/* ---------- Problem grid ---------- */
.problem-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; margin-top: 36px; }
.problem { background: var(--white); border: 1px solid var(--line); border-left: 4px solid var(--green-500); border-radius: 12px; padding: 24px; }
.problem h3 { font-size: 1.1rem; }
.problem p { margin: 0; }
@media (max-width: 860px) { .problem-grid { grid-template-columns: 1fr; } }

/* ---------- Split (image + text) ---------- */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 44px; align-items: center; }
.split--reverse .split__media { order: 2; }
.split__media img, .split__media svg { border-radius: var(--radius); width: 100%; }
.split figure { margin: 0; }
.split figcaption { font-size: 0.85rem; color: var(--muted); margin-top: 8px; text-align: center; }
@media (max-width: 860px) {
  .split { grid-template-columns: 1fr; gap: 26px; }
  .split--reverse .split__media { order: 0; }
}

.diagram-wrap { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); }

/* ---------- Steps list ---------- */
.steps { list-style: none; counter-reset: step; padding: 0; margin: 24px 0 0; }
.steps li { position: relative; padding: 0 0 18px 52px; }
.steps li::before {
  counter-increment: step; content: counter(step);
  position: absolute; left: 0; top: 0; width: 34px; height: 34px;
  background: var(--green-500); color: #fff; border-radius: 50%;
  display: grid; place-items: center; font-weight: 700;
}
.steps li strong { color: var(--blue-900); }

/* ---------- CTA band ---------- */
.cta-band { background: linear-gradient(120deg, var(--green-600), var(--blue-600)); color: #fff; text-align: center; padding: 66px 0; }
.cta-band h2 { color: #fff; }
.cta-band p { color: rgba(255, 255, 255, 0.9); max-width: 560px; margin: 0 auto 24px; }

/* ---------- About / team ---------- */
.team { display: grid; grid-template-columns: repeat(2, 1fr); gap: 30px; margin-top: 40px; }
.member { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.member__photo { width: 100%; height: 300px; object-fit: cover; object-position: center 20%; background: var(--bg-soft); }
@media (max-width: 720px) { .member__photo { height: 260px; } }
.member__body { padding: 24px; }
.member__role { color: var(--green-600); font-weight: 600; font-size: 0.9rem; text-transform: uppercase; letter-spacing: 0.05em; }
.member h3 { margin: 4px 0 10px; }
@media (max-width: 720px) { .team { grid-template-columns: 1fr; } }

.values { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; margin-top: 36px; }
@media (max-width: 860px) { .values { grid-template-columns: 1fr; } }

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 44px; align-items: start; }
@media (max-width: 860px) { .contact-grid { grid-template-columns: 1fr; } }

.form { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow); }
.field { margin-bottom: 18px; }
.field label { display: block; font-weight: 600; font-size: 0.92rem; margin-bottom: 6px; color: var(--blue-900); }
.field input, .field select, .field textarea {
  width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px;
  font-family: inherit; font-size: 1rem; color: var(--ink); background: var(--white);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.field input:focus, .field select:focus, .field textarea:focus {
  outline: none; border-color: var(--green-500); box-shadow: 0 0 0 3px rgba(23, 185, 120, 0.15);
}
.field textarea { resize: vertical; min-height: 130px; }
.field--row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 520px) { .field--row { grid-template-columns: 1fr; } }
.field--check { display: flex; align-items: center; gap: 10px; }
.field--check input { width: auto; }
.field--check label { margin: 0; }
.hp { position: absolute; left: -9999px; opacity: 0; height: 0; width: 0; }

.form__note { font-size: 0.85rem; color: var(--muted); margin-top: 4px; }
.form__status { margin-top: 16px; padding: 14px 16px; border-radius: 10px; font-weight: 500; display: none; }
.form__status.show { display: block; }
.form__status.success { background: rgba(23, 185, 120, 0.12); color: var(--green-600); border: 1px solid rgba(23, 185, 120, 0.3); }
.form__status.error { background: rgba(220, 53, 69, 0.1); color: #c0392b; border: 1px solid rgba(220, 53, 69, 0.25); }

.info-card { background: var(--blue-900); color: #fff; border-radius: var(--radius); padding: 30px; }
.info-card h3 { color: #fff; }
.info-card p, .info-card a { color: rgba(255, 255, 255, 0.85); }
.info-card a:hover { color: var(--green-400); }
.info-item { display: flex; gap: 14px; margin-bottom: 20px; }
.info-item svg { flex: 0 0 22px; width: 22px; height: 22px; margin-top: 3px; color: var(--green-400); }
.map-embed { border: 0; width: 100%; height: 280px; border-radius: var(--radius); margin-top: 24px; }

/* ---------- Footer ---------- */
.site-footer { background: var(--bg-dark); color: rgba(255, 255, 255, 0.72); padding: 54px 0 26px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 34px; }
.site-footer h4 { color: #fff; font-size: 1rem; margin: 0 0 14px; }
.site-footer a { color: rgba(255, 255, 255, 0.72); display: block; padding: 4px 0; }
.site-footer a:hover { color: var(--green-400); }
.footer-brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 1.2rem; color: #fff; margin-bottom: 12px; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.1); margin-top: 34px; padding-top: 20px; font-size: 0.88rem; text-align: center; }
@media (max-width: 720px) { .footer-grid { grid-template-columns: 1fr; gap: 24px; } }

/* ---------- Page header (About / Contact) ---------- */
.page-hero { background: linear-gradient(160deg, var(--blue-900), var(--blue-700, var(--blue-800))); color: #fff; padding: 62px 0; }
.page-hero h1 { color: #fff; }
.page-hero p { color: rgba(255, 255, 255, 0.85); max-width: 640px; font-size: 1.1rem; }