/* Neptune Observatory — Design Tokens & Global Styles */

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

:root {
  --color-neptune-deep: #1b1f3a;
  --color-neptune-mid: #2d3a8c;
  --color-neptune-bright: #4a7cf7;
  --color-neptune-glow: #7eb8ff;
  --color-neptune-ice: #c8e0ff;
  --color-neptune-surface: #0f1328;
  --color-storm-accent: #6c5ce7;
  --color-triton-teal: #00b894;
  --color-text-primary: #e8eaf6;
  --color-text-secondary: #9fa8da;
  --color-text-dark: #1a1a2e;
  --color-danger: #ff6b6b;
  --color-warning: #f0a500;
  --color-focus-ring: #7eb8ff;
  --color-card-bg: rgba(45, 58, 140, 0.3);
  --color-card-border: rgba(126, 184, 255, 0.15);
  --color-input-bg: rgba(15, 19, 40, 0.6);
  --color-input-border: rgba(126, 184, 255, 0.3);

  --font-heading: 'Inter', system-ui, -apple-system, sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-glow: 0 0 12px rgba(126, 184, 255, 0.3);
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.3);
  --transition-standard: 150ms ease;
  --transition-smooth: 300ms ease;

  --container-max: 1200px;
  --container-narrow: 800px;
}

/* Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-neptune-deep);
  background-image:
    radial-gradient(ellipse at 20% 50%, rgba(45, 58, 140, 0.4) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(108, 92, 231, 0.2) 0%, transparent 40%),
    radial-gradient(circle at 50% 80%, rgba(74, 124, 247, 0.1) 0%, transparent 50%);
  min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-primary);
}

h1 { font-size: 2.5rem; margin-bottom: 1rem; }
h2 { font-size: 1.875rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.375rem; margin-bottom: 0.5rem; }
h4 { font-size: 1.125rem; margin-bottom: 0.5rem; }

p {
  margin-bottom: 1rem;
  color: var(--color-text-secondary);
}

a {
  color: var(--color-neptune-glow);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color var(--transition-standard);
}

a:hover {
  color: var(--color-neptune-ice);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Layout */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.container--narrow {
  max-width: var(--container-narrow);
}

/* Focus Styles (Accessible) */
:focus-visible {
  outline: 2px solid var(--color-focus-ring);
  outline-offset: 2px;
  box-shadow: var(--shadow-glow);
  border-radius: var(--radius-sm);
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 10000;
  padding: 0.75rem 1.5rem;
  background: var(--color-neptune-bright);
  color: #fff;
  font-weight: 600;
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: top var(--transition-standard);
}

.skip-link:focus {
  top: 4.5rem;
  outline: 2px solid #fff;
  outline-offset: 2px;
}

/* Site Header */
.site-header {
  background: var(--color-neptune-surface);
  border-bottom: 1px solid var(--color-card-border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--color-text-primary);
  font-weight: 700;
  font-size: 1.25rem;
  white-space: nowrap;
}

.site-logo:hover {
  color: var(--color-neptune-glow);
}

.site-logo svg {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

/* Main Navigation */
.main-nav ul {
  display: flex;
  list-style: none;
  gap: 0.25rem;
}

.main-nav a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--color-text-secondary);
  text-decoration: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  font-size: 0.9375rem;
  transition: color var(--transition-standard), background var(--transition-standard);
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--color-text-primary);
  background: rgba(126, 184, 255, 0.1);
}

/* Hero Section */
.hero {
  padding: 4rem 0;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  background: linear-gradient(135deg, var(--color-neptune-glow), var(--color-storm-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 1.5rem;
}

.hero p {
  font-size: 1.25rem;
  max-width: 600px;
  margin: 0 auto 2rem;
}

.hero-image {
  width: 100%;
  max-width: 600px;
  margin: 2rem auto 0;
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-card), 0 0 60px rgba(74, 124, 247, 0.2);
}

.hero-image img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

/* Main Content */
main {
  padding: 3rem 0;
  min-height: 60vh;
}

/* Site Footer */
.site-footer {
  background: var(--color-neptune-surface);
  border-top: 1px solid var(--color-card-border);
  padding: 2rem 0;
  margin-top: 4rem;
  text-align: center;
}

.site-footer p {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin: 0;
}

/* Section Spacing */
.section {
  margin-bottom: 4rem;
}

.section-header {
  margin-bottom: 2rem;
}

/* Utility */
.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;
}

/* Responsive */
@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  .hero h1 { font-size: 2.25rem; }
  h2 { font-size: 1.5rem; }
  .hero { padding: 2rem 0; }

  .site-header .container {
    flex-wrap: wrap;
  }

  .main-nav ul {
    flex-wrap: wrap;
  }
}