/* Static AI site template — multi-theme presets + auto-hide header. System fonts only. */
:root {
  --radius-pill: 999px;
  --radius-card: 14px;
  --font-sans: system-ui, "Segoe UI", Roboto, Ubuntu, Cantarell, "Noto Sans", sans-serif;
  --max-width: 1180px;
  --max-width-narrow: 760px;
  --section-padding-y: clamp(2.75rem, 6vw, 5rem);
  --header-height: 4rem;
  --bp-md: 768px;
  --bp-lg: 1024px;
}

html[data-theme='default'] {
  --color-bg: #0f1118;
  --color-bg-elevated: #161a24;
  --color-surface: #ffffff;
  --color-surface-muted: #f4f5f8;
  --color-text: #1a1d26;
  --color-text-muted: #5c6370;
  --color-on-dark: #f2f4f8;
  --color-on-dark-muted: #b8c0cc;
  --color-accent: #5b4fdc;
  --color-accent-soft: #7c6ff0;
  --shadow-card: 0 8px 28px rgba(15, 17, 24, 0.12);
  --shadow-header: 0 1px 0 rgba(255, 255, 255, 0.06);
  --color-header-bg: rgba(15, 17, 24, 0.92);
  --color-footer-bg: #0c0e14;
  --hero-grad-1: #12152a;
  --hero-grad-2: #1a1440;
  --hero-grad-3: #12152a;
  --placeholder-border: rgba(26, 29, 38, 0.12);
}

html[data-theme='ocean'] {
  --color-bg: #0a1628;
  --color-bg-elevated: #0f2137;
  --color-surface: #ffffff;
  --color-surface-muted: #e8f4f2;
  --color-text: #0f172a;
  --color-text-muted: #475569;
  --color-on-dark: #ecfeff;
  --color-on-dark-muted: #94d6cc;
  --color-accent: #0d9488;
  --color-accent-soft: #14b8a6;
  --shadow-card: 0 8px 28px rgba(10, 22, 40, 0.14);
  --shadow-header: 0 1px 0 rgba(255, 255, 255, 0.08);
  --color-header-bg: rgba(10, 22, 40, 0.92);
  --color-footer-bg: #050f18;
  --hero-grad-1: #0c4a6e;
  --hero-grad-2: #115e59;
  --hero-grad-3: #0c4a6e;
  --placeholder-border: rgba(15, 23, 42, 0.12);
}

html[data-theme='warm'] {
  --color-bg: #1c1410;
  --color-bg-elevated: #292018;
  --color-surface: #fffdfb;
  --color-surface-muted: #faf3ed;
  --color-text: #1c1917;
  --color-text-muted: #57534e;
  --color-on-dark: #fff7ed;
  --color-on-dark-muted: #fdba74;
  --color-accent: #ea580c;
  --color-accent-soft: #fb923c;
  --shadow-card: 0 8px 28px rgba(28, 20, 16, 0.12);
  --shadow-header: 0 1px 0 rgba(255, 255, 255, 0.06);
  --color-header-bg: rgba(28, 20, 16, 0.92);
  --color-footer-bg: #0f0c0a;
  --hero-grad-1: #431407;
  --hero-grad-2: #7c2d12;
  --hero-grad-3: #431407;
  --placeholder-border: rgba(28, 25, 23, 0.15);
}

html[data-theme='forest'] {
  --color-bg: #0f1811;
  --color-bg-elevated: #142819;
  --color-surface: #ffffff;
  --color-surface-muted: #ecfdf5;
  --color-text: #14532d;
  --color-text-muted: #3d684d;
  --color-on-dark: #ecfccb;
  --color-on-dark-muted: #bee6a0;
  --color-accent: #15803d;
  --color-accent-soft: #22c55e;
  --shadow-card: 0 8px 28px rgba(15, 24, 17, 0.14);
  --shadow-header: 0 1px 0 rgba(255, 255, 255, 0.07);
  --color-header-bg: rgba(15, 24, 17, 0.92);
  --color-footer-bg: #0a120c;
  --hero-grad-1: #14532d;
  --hero-grad-2: #166534;
  --hero-grad-3: #14532d;
  --placeholder-border: rgba(20, 83, 45, 0.15);
}

html[data-theme='mono'] {
  --color-bg: #171717;
  --color-bg-elevated: #262626;
  --color-surface: #fafafa;
  --color-surface-muted: #e5e5e5;
  --color-text: #171717;
  --color-text-muted: #525252;
  --color-on-dark: #fafafa;
  --color-on-dark-muted: #a3a3a3;
  --color-accent: #3b3b3b;
  --color-accent-soft: #525252;
  --shadow-card: 0 8px 28px rgba(0, 0, 0, 0.15);
  --shadow-header: 0 1px 0 rgba(255, 255, 255, 0.06);
  --color-header-bg: rgba(23, 23, 23, 0.94);
  --color-footer-bg: #0a0a0a;
  --hero-grad-1: #262626;
  --hero-grad-2: #404040;
  --hero-grad-3: #262626;
  --placeholder-border: rgba(23, 23, 23, 0.12);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding-top: var(--header-height);
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-surface-muted);
  line-height: 1.6;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  border-radius: var(--radius-card);
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.08);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link:focus {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 100;
  padding: 0.5rem 1rem;
  background: var(--color-surface);
  color: var(--color-text);
  border-radius: var(--radius-pill);
  box-shadow: var(--shadow-card);
  clip: auto;
  width: auto;
  height: auto;
  margin: 0;
  overflow: visible;
}

.container,
.wrap {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 1.75rem);
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  min-height: var(--header-height);
  background: var(--color-header-bg);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  box-shadow: var(--shadow-header);
  transform: translateY(0);
  transition: transform 0.28s ease;
}

.site-header.is-header-hidden {
  transform: translateY(-100%);
}

@media (prefers-reduced-motion: reduce) {
  .site-header {
    transition: none;
  }

  .site-header.is-header-hidden {
    transform: translateY(0);
  }
}

.site-header--minimal .header-inner {
  justify-content: flex-start;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  padding-block: 0.85rem;
  flex-wrap: nowrap;
  overflow: hidden;
}

.logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-on-dark);
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.logo:hover,
.logo:focus-visible {
  color: var(--color-accent-soft);
}

.main-nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.65rem 1.25rem;
  align-items: center;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

@media (max-width: 767px) {
  .main-nav {
    width: 100%;
    padding-bottom: 0.15rem;
  }
}

.main-nav__link {
  color: var(--color-on-dark-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
  white-space: nowrap;
}

.main-nav__link:hover,
.main-nav__link:focus-visible {
  color: var(--color-on-dark);
  border-bottom-color: var(--color-accent);
  outline: none;
}

.nav-cta {
  display: flex;
  gap: 0.75rem;
}

main#main {
  outline: none;
}

main#main > .section:first-child {
  scroll-margin-top: calc(var(--header-height) + 0.5rem);
}

.section {
  scroll-margin-top: calc(var(--header-height) + 1rem);
}

.section--band:nth-of-type(odd) {
  background: var(--color-surface);
}

.section--band:nth-of-type(even) {
  background: var(--color-surface-muted);
}

.section--hero,
.section--hero.section--band {
  background: linear-gradient(
    155deg,
    var(--hero-grad-1) 0%,
    var(--hero-grad-2) 42%,
    var(--hero-grad-3) 100%
  );
  color: var(--color-on-dark);
  padding-block: var(--section-padding-y);
}

.section--hero .prose,
.section--hero .section-lead {
  color: var(--color-on-dark-muted);
}

.section--hero h1,
.section--hero h2 {
  color: var(--color-on-dark);
}

.section:not(.section--hero) {
  padding-block: var(--section-padding-y);
}

.section--promo,
.section--metrics {
  background: var(--color-bg-elevated);
  color: var(--color-on-dark);
}

.section--promo .prose,
.section--metrics .prose,
.section--promo .section-lead {
  color: var(--color-on-dark-muted);
}

.section--footer-wrap {
  padding: 0;
  background: var(--color-footer-bg);
}

.hero {
  display: grid;
  gap: 2rem;
  align-items: center;
}

@media (min-width: 768px) {
  .hero {
    grid-template-columns: 1.1fr 0.9fr;
  }
}

.hero__copy h1 {
  font-size: clamp(2rem, 4.5vw, 3rem);
  line-height: 1.12;
  margin: 0 0 1rem;
  letter-spacing: -0.03em;
}

.hero__copy h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
}

.section-lead {
  font-size: 1.1rem;
  max-width: 42rem;
  margin: 0 0 1.25rem;
}

.prose {
  max-width: var(--max-width-narrow);
  margin: 0 0 1rem;
}

.prose.small {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

h1,
h2 {
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.35rem, 2.5vw, 1.85rem);
  margin: 0 0 0.75rem;
}

.grid {
  display: grid;
  gap: 1.75rem;
}

.grid--split {
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .grid--split {
    grid-template-columns: 1fr 1fr;
    align-items: start;
  }
}

.card,
.card--media {
  border-radius: var(--radius-card);
  background: var(--color-surface);
  box-shadow: var(--shadow-card);
  padding: 1.25rem;
}

.section--hero .card--media,
.section--promo .card--media {
  background: rgba(255, 255, 255, 0.06);
  box-shadow: none;
}

.card--media-placeholder {
  min-height: clamp(10rem, 28vw, 14rem);
  width: 100%;
  border-radius: var(--radius-card);
  background: linear-gradient(
    145deg,
    var(--color-surface-muted) 0%,
    var(--color-surface) 45%,
    var(--color-surface-muted) 100%
  );
  border: 1px dashed var(--placeholder-border);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.5);
}

.section--hero .card--media-placeholder,
.section--promo .card--media-placeholder {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.2);
}

.hero__media:has(.card--media-placeholder:only-child) {
  min-height: clamp(10rem, 28vw, 14rem);
}

.icon-list {
  list-style: none;
  padding: 0;
  margin: 1rem 0;
}

.icon-list__item {
  position: relative;
  padding-left: 1.35rem;
  margin-bottom: 0.5rem;
}

.icon-list__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: var(--color-accent);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.35rem;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.12s ease, background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.btn--primary {
  background: var(--color-accent);
  color: #fff;
}

.btn--primary:hover {
  background: var(--color-accent-soft);
}

.btn--secondary {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.35);
  color: var(--color-on-dark);
}

.section:not(.section--hero) .btn--secondary {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1rem;
  margin-top: 1.5rem;
}

.prefooter-cta {
  text-align: center;
  max-width: 40rem;
  margin-inline: auto;
  background: var(--color-surface);
  padding: 2.5rem 1.5rem;
}

.prefooter-cta .btn {
  margin: 0.35rem;
}

.footer {
  padding: 2.5rem 0 3rem;
  color: var(--color-on-dark-muted);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.footer a {
  color: var(--color-on-dark-muted);
  text-decoration: none;
  font-size: 0.9rem;
}

.footer a:hover,
.footer a:focus-visible {
  color: var(--color-on-dark);
  text-decoration: underline;
}

.footer__inner {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.footer__cols {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
}

@media (min-width: 1024px) {
  .header-inner {
    flex-wrap: nowrap;
  }

  .hero {
    grid-template-columns: 1.15fr 0.85fr;
    gap: 2.5rem;
  }

  .section .grid--split > div:first-child .prose {
    max-width: 42rem;
  }
}