/* Avarta Fuel Tech — EWS + SINTEF STOP visual language (text-only) */

@import url("https://fonts.googleapis.com/css2?family=Montserrat:wght@400;500;600;700&display=swap");

:root {
  --brand: #006449;
  --brand-hover: #004d38;
  --hero: #003627;
  --teal: #0a4d5c;
  --accent-yellow: #fff580;
  --surface: #ffffff;
  --pale-card: #fefff3;
  --band: #f4f4f4;
  --band-soft: #fafafa;
  --text: #1a1b1f;
  --text-alt: #202020;
  --muted: #4a4a4a;
  --border: #e2e2e2;
  --divider: #eeeeee;
  --border-soft: #ddd;
  --max-read: 42rem;
  --container: 1140px;
  --font: "Montserrat", system-ui, -apple-system, "Segoe UI", sans-serif;
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  font-weight: 400;
  line-height: 28px;
  color: var(--text);
  background: var(--surface);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Thin top brand bar (research-doc edge) */
.brand-bar {
  height: 4px;
  background: var(--brand);
  border-bottom: 2px solid var(--accent-yellow);
}

/* Header */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--divider);
  padding: 1.25rem 1.75rem;
  position: sticky;
  top: 0;
  z-index: 50;
}

.site-header-inner {
  max-width: var(--container);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem 2rem;
}

.site-name {
  font-family: var(--font);
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  color: var(--text);
  max-width: 18rem;
  line-height: 1.35;
}

.site-name span {
  display: block;
  font-weight: 400;
  color: var(--muted);
  font-size: 0.6875rem;
  margin-top: 0.2rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

nav {
  flex: 1 1 auto;
  min-width: 0;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 0.35rem 1.25rem;
  row-gap: 0.5rem;
}

nav ul li:last-child {
  margin-left: 0.25rem;
}

nav a {
  font-family: var(--font);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 1px;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--muted);
  padding: 0.35rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

nav a:hover {
  color: var(--brand);
}

nav a[aria-current="page"] {
  color: var(--text);
  font-weight: 600;
  border-bottom-color: var(--brand);
}

nav a.nav-cta {
  background: var(--brand);
  color: #fff;
  padding: 0.65rem 1.15rem;
  border-bottom: none;
  letter-spacing: 2px;
  font-weight: 600;
  white-space: nowrap;
  flex-shrink: 0;
}

nav a.nav-cta:hover {
  background: var(--brand-hover);
  color: #fff;
}

nav a.nav-cta[aria-current="page"] {
  background: var(--hero);
  color: #fff;
  border-bottom: none;
}

/* Page shell */
.page {
  flex: 1;
  width: 100%;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 1.75rem;
}

.container-narrow {
  max-width: var(--max-read);
  margin: 0 auto;
  padding: 0 1.75rem;
}

/* Hero band (deep green, text-only) */
.hero {
  background: var(--hero);
  color: #fff;
  padding: 4.5rem 0 4rem;
  position: relative;
}

.hero::after {
  content: "";
  display: block;
  height: 4px;
  background: var(--accent-yellow);
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
}

.hero .container-narrow {
  padding-left: 1.75rem;
  padding-right: 1.75rem;
}

.hero h1 {
  color: #fff;
  margin: 0 0 1.25rem;
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
  max-width: 18ch;
}

.hero .standfirst {
  color: rgba(255, 255, 255, 0.88);
  font-size: 1.0625rem;
  line-height: 1.7;
  margin: 0;
  max-width: 40rem;
}

/* Subpage title band */
.page-banner {
  background: var(--band);
  border-bottom: 1px solid var(--divider);
  padding: 3.5rem 0 2.75rem;
  position: relative;
}

.page-banner::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: var(--brand);
}

.page-banner h1 {
  margin: 0;
  color: var(--hero);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

/* Main content sections */
.section {
  padding: 4rem 0;
}

.section-band {
  background: var(--band);
}

.section + .section {
  border-top: 1px solid var(--divider);
}

h1 {
  font-family: var(--font);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 1.25rem;
  color: var(--text);
}

h2 {
  font-family: var(--font);
  font-size: clamp(1.35rem, 2.5vw, 2rem);
  font-weight: 600;
  line-height: 1.35;
  letter-spacing: -0.015em;
  margin: 0 0 1rem;
  color: var(--text);
}

.section-label {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--teal);
  margin: 0 0 0.75rem;
}

h3 {
  font-family: var(--font);
  font-size: 1.125rem;
  font-weight: 600;
  margin: 0 0 0.75rem;
  color: var(--text);
}

p {
  margin: 0 0 1rem;
  color: var(--text-alt);
}

p:last-child {
  margin-bottom: 0;
}

.standfirst {
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--muted);
  margin-bottom: 0;
}

.lead-rule {
  border: none;
  border-top: 1px solid var(--divider);
  margin: 2.5rem 0;
}

/* Lists */
ul.convert-list,
ul.contact-list {
  margin: 0 0 1.25rem;
  padding: 0;
  list-style: none;
}

ul.convert-list li,
ul.contact-list li {
  position: relative;
  padding: 0.85rem 0 0.85rem 1.35rem;
  border-bottom: 1px solid var(--divider);
  margin: 0;
  color: var(--text-alt);
}

ul.convert-list li:last-child,
ul.contact-list li:last-child {
  border-bottom: none;
}

ul.convert-list li::before,
ul.contact-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.35rem;
  width: 8px;
  height: 8px;
  background: var(--brand);
  border-radius: 50%;
}

.note {
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.6;
  margin-top: 1rem;
  padding-left: 0.85rem;
  border-left: 3px solid var(--accent-yellow);
}

/* How we work block */
.work-block {
  display: grid;
  gap: 1rem;
}

.work-block p {
  margin: 0;
  padding: 1.15rem 1.35rem;
  background: var(--pale-card);
  border: 1px solid var(--border);
  border-left: 4px solid var(--brand);
}

/* CTAs */
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2.5rem;
}

.btn {
  font-family: var(--font);
  display: inline-block;
  padding: 0.85rem 1.6rem;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  text-decoration: none;
  border: 1px solid var(--brand);
  background: var(--brand);
  color: #fff;
  border-radius: 0;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  background: var(--brand-hover);
  border-color: var(--brand-hover);
  color: #fff;
}

.btn-secondary {
  background: transparent;
  color: var(--brand);
}

.btn-secondary:hover {
  background: var(--brand);
  color: #fff;
}

/* Platform numbered cards (SINTEF handbook feel) */
.platforms-grid {
  display: grid;
  gap: 1.5rem;
}

.platform {
  background: var(--pale-card);
  border: 1px solid var(--border);
  padding: 1.75rem 1.75rem 1.75rem 1.85rem;
  border-left: 4px solid var(--brand);
  position: relative;
}

.platform h2 {
  margin-top: 0;
  margin-bottom: 1rem;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  color: var(--hero);
  line-height: 1.35;
}

.platform p + p {
  margin-top: 0.85rem;
}

.rule-block {
  margin-top: 2.5rem;
  padding: 1.5rem 1.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: 4px solid var(--brand);
  box-shadow: 0 1px 0 var(--divider);
}

.rule-block h2 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  color: var(--teal);
  font-size: 1.125rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-weight: 600;
}

.rule-block p {
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--text);
}

/* About sections */
.about-block {
  padding: 0 0 2.5rem;
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--divider);
}

.about-block:last-of-type {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.about-block h2 {
  color: var(--hero);
  font-size: clamp(1.25rem, 2vw, 1.75rem);
}

/* Contact */
.contact-meta {
  margin-top: 0.5rem;
  padding: 1.5rem 1.75rem;
  background: var(--pale-card);
  border: 1px solid var(--border);
  border-left: 4px solid var(--brand);
}

.contact-meta p {
  margin-bottom: 0.4rem;
  font-weight: 500;
}

.contact-meta p:last-child {
  margin-bottom: 0;
}

/* Footer */
.site-footer {
  background: var(--hero);
  border-top: none;
  padding: 2.5rem 1.75rem;
  font-family: var(--font);
  font-size: 0.75rem;
  color: rgba(255, 255, 255, 0.75);
  line-height: 1.6;
  margin-top: auto;
}

.site-footer-inner {
  max-width: var(--container);
  margin: 0 auto;
}

.site-footer p {
  margin: 0 0 0.35rem;
  color: rgba(255, 255, 255, 0.75);
  font-size: inherit;
}

.site-footer p:last-child {
  margin-bottom: 0;
  margin-top: 0.75rem;
  color: rgba(255, 255, 255, 0.55);
}

/* Mobile */
@media (max-width: 720px) {
  .site-header {
    padding: 1rem 1.25rem;
  }

  .site-header-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 0.85rem;
  }

  .site-name {
    max-width: none;
  }

  nav {
    width: 100%;
  }

  nav ul {
    justify-content: flex-start;
    gap: 0.35rem 0.9rem;
    row-gap: 0.55rem;
  }

  nav a {
    letter-spacing: 0.6px;
    font-size: 11px;
  }

  nav ul li:last-child {
    margin-left: auto;
  }

  nav a.nav-cta {
    padding: 0.55rem 0.9rem;
  }

  .hero {
    padding: 3.25rem 0 3rem;
  }

  .hero h1 {
    max-width: none;
  }

  .section {
    padding: 3rem 0;
  }

  .container,
  .container-narrow,
  .hero .container-narrow {
    padding-left: 1.25rem;
    padding-right: 1.25rem;
  }

  .page-banner {
    padding: 2.5rem 0 2rem;
  }

  .platform {
    padding: 1.35rem;
  }

  .site-footer {
    padding: 2rem 1.25rem;
  }
}


/* References */
.ref-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.ref-list > li {
  margin: 0 0 1.75rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--divider, #EEEEEE);
  font-size: 1rem;
  line-height: 1.75;
}
.ref-list > li:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}
.ref-num {
  font-family: Montserrat, system-ui, sans-serif;
  font-weight: 600;
  color: var(--brand, #006449);
  margin-right: 0.35rem;
}
.ref-list a {
  color: var(--brand, #006449);
  word-break: break-word;
}
.ref-note {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.875rem;
  color: var(--muted, #5d6c7b);
}


/* Scientific figures */
.figure-block {
  margin: 2.5rem 0;
  padding: 1.5rem;
  background: #FEFFF3;
  border: 1px solid #EEEEEE;
}
.figure-block img {
  display: block;
  width: 100%;
  height: auto;
  background: #fff;
}
.figure-block figcaption {
  font-family: Montserrat, system-ui, sans-serif;
  font-size: 0.8rem;
  line-height: 1.5;
  color: #5d6c7b;
  margin-top: 0.85rem;
}
.figure-block .fig-source {
  display: block;
  margin-top: 0.35rem;
  font-size: 0.72rem;
}


.tech-link-note {
  margin-top: 1.75rem;
}

.tech-link-note a {
  color: var(--brand);
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 2px;
}

.tech-link-note a:hover {
  color: var(--brand-hover);
}


.mv-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}
.mv-card {
  background: var(--pale-card, #fefff3);
  border: 1px solid var(--divider, #eee);
  padding: 1.5rem 1.35rem;
}
.mv-card h2 {
  margin-top: 0;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--brand, #006449);
}
.mv-card p {
  margin: 0;
  color: var(--muted, #4a4a4a);
}
@media (max-width: 700px) {
  .mv-grid { grid-template-columns: 1fr; }
}