/* Basic layout */
:root {
  color-scheme: dark;
  --fs-bg: #020617;
  --fs-bg-alt: #020617;
  --fs-surface: rgba(15, 23, 42, 0.9);
  --fs-border: rgba(148, 163, 184, 0.2);
  --fs-accent: #38bdf8;
  --fs-accent-soft: rgba(56, 189, 248, 0.15);
  --fs-text: #e5e7eb;
  --fs-muted: #9ca3af;
  --fs-radius: 14px;
  --fs-shadow-soft: 0 24px 60px rgba(15, 23, 42, 0.7);
}

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

body {
  margin: 0;
  min-height: 100vh;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    ui-sans-serif, sans-serif;
  color: var(--fs-text);
  background:
    radial-gradient(circle at top left, rgba(56, 189, 248, 0.25), transparent),
    radial-gradient(circle at 80% 0, rgba(129, 140, 248, 0.2), transparent),
    radial-gradient(circle at bottom, rgba(15, 23, 42, 0.95), #020617);
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas,
    "Liberation Mono", "Courier New", monospace;
  font-size: 0.9em;
}

pre {
  margin: 0;
  font-family: inherit;
}

.fs-container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Nav */
.fs-nav {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(16px);
  background: linear-gradient(
    to bottom,
    rgba(15, 23, 42, 0.95),
    rgba(15, 23, 42, 0.75),
    transparent
  );
  border-bottom: 1px solid rgba(148, 163, 184, 0.2);
}

/* Alpha ribbon */
.fs-ribbon {
  position: fixed;
  top: 0.75rem;
  right: -3.2rem;
  z-index: 30;
  background: linear-gradient(135deg, #f97316, #ec4899);
  color: #0b1120;
  padding: 0.25rem 3.8rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  transform: rotate(45deg);
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.8);
}

.fs-nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1.5rem;
}

.fs-nav-left {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
}

.fs-logo {
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-size: 0.9rem;
}

.fs-tagline {
  font-size: 0.85rem;
  color: var(--fs-muted);
}

.fs-nav-links {
  display: flex;
  gap: 1.2rem;
  font-size: 0.9rem;
}

.fs-nav-links a {
  color: var(--fs-muted);
  text-decoration: none;
  padding: 0.15rem 0;
}

.fs-nav-links a:hover {
  color: var(--fs-text);
}

/* Hero */
.fs-hero {
  padding: 4.5rem 0 3.5rem;
}

.fs-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: 3rem;
  align-items: center;
}

.fs-hero-text h1 {
  font-size: clamp(2.4rem, 3vw, 3rem);
  line-height: 1.1;
  margin: 0 0 1rem;
}

.fs-hero-subtitle {
  margin: 0 0 1.5rem;
  color: var(--fs-muted);
  max-width: 34rem;
}

.fs-hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-bottom: 0.9rem;
}

.fs-hero-note {
  font-size: 0.85rem;
  color: var(--fs-muted);
}

.fs-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.55rem 1.4rem;
  font-size: 0.9rem;
  border: 1px solid transparent;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease,
    transform 0.1s ease;
}

.fs-btn-primary {
  background: linear-gradient(135deg, #38bdf8, #6366f1);
  color: #0b1120;
  box-shadow: 0 18px 40px rgba(56, 189, 248, 0.45);
}

.fs-btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 20px 48px rgba(56, 189, 248, 0.55);
}

.fs-btn-secondary {
  background: rgba(15, 23, 42, 0.9);
  color: var(--fs-text);
  border-color: rgba(148, 163, 184, 0.4);
}

.fs-btn-secondary:hover {
  border-color: var(--fs-accent);
  color: var(--fs-accent);
}

.fs-hero-media {
  display: flex;
  justify-content: center;
}

.fs-hero-image-frame {
  position: relative;
  width: 100%;
  max-width: 420px;
  border-radius: 1.5rem;
  padding: 0.75rem;
  background: radial-gradient(circle at top left, #22d3ee, #6366f1);
  box-shadow: var(--fs-shadow-soft);
}

.fs-hero-image-frame img {
  width: 100%;
  display: block;
  border-radius: 1.15rem;
  border: 1px solid rgba(15, 23, 42, 0.6);
  background: radial-gradient(circle at top, #020617, #020617);
}

.fs-hero-image-placeholder {
  position: absolute;
  inset: 0.75rem;
  border-radius: 1.15rem;
  border: 1px dashed rgba(148, 163, 184, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  font-size: 0.8rem;
  color: var(--fs-muted);
  text-align: center;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.25s ease;
  background: radial-gradient(circle at top, rgba(15, 23, 42, 0.95), #020617);
}

.fs-hero-image--placeholder + .fs-hero-image-placeholder {
  opacity: 1;
}

/* Sections */
.fs-section {
  padding: 3rem 0;
}

.fs-section-alt {
  padding: 3rem 0;
}

.fs-section h2 {
  font-size: 1.5rem;
  margin: 0 0 0.5rem;
}

.fs-section-intro {
  margin: 0 0 2rem;
  color: var(--fs-muted);
  max-width: 38rem;
}

/* Feature grid */
.fs-feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.4rem;
}

.fs-card {
  border-radius: var(--fs-radius);
  background: var(--fs-surface);
  border: 1px solid var(--fs-border);
  padding: 1.1rem 1.2rem;
  box-shadow: 0 16px 40px rgba(15, 23, 42, 0.7);
}

.fs-card h3 {
  margin: 0 0 0.35rem;
  font-size: 1rem;
}

.fs-card p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--fs-muted);
}

.fs-card-link {
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s ease, transform 0.1s ease,
    box-shadow 0.15s ease, background 0.15s ease;
}

.fs-card-link:hover {
  border-color: var(--fs-accent);
  transform: translateY(-1px);
  box-shadow: 0 22px 52px rgba(56, 189, 248, 0.3);
  background: radial-gradient(circle at top left, var(--fs-accent-soft), #020617);
}

/* Architecture / code layout */
.fs-arch-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 2rem;
  align-items: flex-start;
}

.fs-code-card {
  border-radius: var(--fs-radius);
  background: #020617;
  border: 1px solid rgba(148, 163, 184, 0.4);
  padding: 1rem 1.1rem;
  box-shadow: var(--fs-shadow-soft);
  overflow-x: auto;
}

.fs-code-card pre,
.fs-code-card code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas,
    "Liberation Mono", "Courier New", monospace;
  font-size: 0.8rem;
  color: #e5e7eb;
}

.fs-list {
  margin: 0;
  padding-left: 1.2rem;
  font-size: 0.9rem;
  color: var(--fs-muted);
}

.fs-list li + li {
  margin-top: 0.35rem;
}

.fs-list-ordered {
  list-style: decimal;
}

.fs-links {
  margin-top: 1rem;
  font-size: 0.9rem;
}

.fs-links a {
  color: var(--fs-accent);
  text-decoration: none;
}

.fs-links a:hover {
  text-decoration: underline;
}

/* Examples */
.fs-example-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1.3rem;
}

/* Links section */
.fs-links-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 2rem;
}

/* Footer */
.fs-footer {
  border-top: 1px solid rgba(148, 163, 184, 0.25);
  padding: 1rem 0 1.4rem;
  margin-top: 1rem;
  background: radial-gradient(circle at bottom, rgba(15, 23, 42, 0.95), #020617);
}

.fs-footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--fs-muted);
}

/* Responsive */
@media (max-width: 960px) {
  .fs-hero-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .fs-hero-media {
    order: -1;
  }

  .fs-feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .fs-arch-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .fs-example-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .fs-links-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .fs-nav-links {
    display: none;
  }
}

@media (max-width: 640px) {
  .fs-feature-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .fs-example-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}