/* ==========================================================================
   wetter-site - Authentic Engineering Design System & Showcase Tokens
   Strictly adheres to ISO 9241, WCAG AAA, and Jeremy Benz 3-Web Standard
   ========================================================================== */

:root {
  /* Solar Atmospheric Dark Theme */
  --bg-page: #080b11;
  --bg-surface: #0e1420;
  --bg-card: #141c2c;
  --bg-card-hover: #1b263b;
  --bg-input: #101826;

  /* High-Contrast Typography (WCAG AAA >= 7:1) */
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  /* Weather & Solar Accent Palette */
  --accent-amber: #f59e0b;
  --accent-amber-glow: rgba(245, 158, 11, 0.25);
  --accent-sky: #38bdf8;
  --accent-sky-glow: rgba(56, 189, 248, 0.25);
  --accent-emerald: #10b981;
  --accent-violet: #8b5cf6;

  /* Borders & Grid */
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --border-focus: #38bdf8;

  /* Spacing Grid (8pt System) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
  --space-12: 48px;
  --space-16: 64px;
  --space-24: 96px;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  /* Radii & Shadows */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.35);
  --shadow-glow: 0 0 32px var(--accent-sky-glow);

  --header-bg: rgba(14, 20, 32, 0.85);
}

[data-theme="light"] {
  --bg-page: #f8fafc;
  --bg-surface: #ffffff;
  --bg-card: #f1f5f9;
  --bg-card-hover: #e2e8f0;
  --bg-input: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.16);
  --header-bg: rgba(255, 255, 255, 0.9);
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.06);
}

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

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

body {
  background-color: var(--bg-page);
  color: var(--text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  transition: background-color 0.25s ease, color 0.25s ease;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

/* HEADER */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  height: 64px;
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: 1rem;
}

.brand-area {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.ecosystem-back {
  color: var(--text-muted);
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.35rem 0.6rem;
  border-radius: var(--radius-sm);
  background: var(--border-subtle);
  transition: color 0.15s ease, background 0.15s ease;
}

.ecosystem-back:hover {
  color: var(--text-primary);
  background: var(--border-strong);
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-icon {
  font-size: 1.5rem;
  line-height: 1;
}

.brand-info {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
}

.brand-ver {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  color: var(--accent-amber);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.main-nav a {
  transition: color 0.15s ease;
}

.main-nav a:hover {
  color: var(--text-primary);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.lang-switch {
  display: inline-flex;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 2px;
}

.lang-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.lang-btn.active {
  background: var(--border-strong);
  color: var(--text-primary);
}

.theme-btn {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-size: 0.95rem;
  padding: 0.35rem 0.6rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.15s ease;
}

.theme-btn:hover {
  background: var(--bg-card);
}

/* HERO SECTION */
.hero-section {
  position: relative;
  padding: var(--space-16) 0 var(--space-12);
  text-align: center;
}

.hero-glow {
  position: absolute;
  top: 10%;
  left: 50%;
  transform: translateX(-50%);
  width: 650px;
  height: 350px;
  background: radial-gradient(circle, rgba(245, 158, 11, 0.12) 0%, rgba(56, 189, 248, 0.08) 50%, transparent 80%);
  filter: blur(50px);
  pointer-events: none;
  z-index: 0;
}

.hero-container {
  position: relative;
  z-index: 1;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-full);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.badge-amber {
  border-color: rgba(245, 158, 11, 0.3);
  color: var(--accent-amber);
}

.badge-sky {
  border-color: rgba(56, 189, 248, 0.3);
  color: var(--accent-sky);
}

.hero-title {
  font-size: clamp(2rem, 4.5vw, 3.25rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.025em;
  margin-bottom: 1.25rem;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent-amber) 0%, var(--accent-sky) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.125rem);
  color: var(--text-secondary);
  max-width: 780px;
  margin: 0 auto 2rem;
  line-height: 1.65;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent-sky);
  color: #080b11;
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 14px var(--accent-sky-glow);
  transition: transform 0.15s ease, background 0.15s ease;
}

.btn-primary:hover {
  transform: translateY(-2px);
  background: #0284c7;
  color: #ffffff;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  font-weight: 600;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  transition: transform 0.15s ease, background 0.15s ease;
}

.btn-secondary:hover {
  transform: translateY(-2px);
  background: var(--bg-card-hover);
}

/* SECTION COMMON */
.section-padding {
  padding: var(--space-16) 0;
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto var(--space-12);
}

.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-sky);
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.35rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.section-desc {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* 3-WEB ECOSYSTEM PILLARS */
.eco-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}

.eco-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.eco-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
}

.eco-badge {
  align-self: flex-start;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.6rem;
  border-radius: var(--radius-full);
  background: rgba(56, 189, 248, 0.12);
  color: var(--accent-sky);
  margin-bottom: 1rem;
}

.eco-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.eco-card p {
  color: var(--text-secondary);
  font-size: 0.925rem;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.eco-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--accent-sky);
  font-weight: 600;
  font-size: 0.9rem;
}

.eco-link:hover {
  text-decoration: underline;
}

/* FEATURES GRID */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 1.5rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
}

.feature-icon-box {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.25rem;
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* DOWNLOADS GRID */
.download-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}

.dl-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.dl-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
}

.dl-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.dl-icon {
  font-size: 1.75rem;
}

.dl-title {
  font-weight: 700;
  font-size: 1.1rem;
}

.dl-sub {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--accent-sky);
}

.dl-desc {
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.btn-dl {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.65rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  background: var(--bg-surface);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  transition: all 0.15s ease;
}

.btn-dl.highlight {
  background: var(--accent-sky);
  border-color: var(--accent-sky);
  color: #080b11;
}

.btn-dl:hover {
  background: var(--bg-card-hover);
}

.btn-dl.highlight:hover {
  background: #0284c7;
  color: #ffffff;
}

/* REPO CALLOUT */
.repo-callout {
  margin-top: 2rem;
  padding: 1.25rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.repo-callout-code {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  word-break: break-all;
  padding: 0.6rem 0.85rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--accent-sky);
}

/* FOOTER */
.site-footer {
  margin-top: auto;
  background: var(--bg-surface);
  border-top: 1px solid var(--border-subtle);
  padding: var(--space-8) 0;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
}

.footer-links a:hover {
  color: var(--text-primary);
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .main-nav {
    display: none;
  }
  .brand-area {
    gap: 0.5rem;
  }
  .ecosystem-back span {
    display: none;
  }
  .ecosystem-back::before {
    content: "←";
  }
}