/* ==========================================================================
   ≡quivalence Ecosystem Landing Page Stylesheet
   Designed with Stone & Graphite aesthetics, sharp edges, and tactical noise.
   ========================================================================== */

:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-display: 'Outfit', var(--font-sans);
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sharp: 2px;
  --transition-smooth: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Dark theme (default) */
:root,
[data-theme="dark"] {
  color-scheme: dark;

  --bg-dark: hsl(220, 18%, 7%);
  --bg-panel: hsla(220, 18%, 11%, 0.6);
  --bg-panel-hover: hsla(220, 18%, 14%, 0.8);
  --bg-input: hsl(220, 18%, 9%);

  --accent: hsl(204, 42%, 48%);
  --accent-hover: hsl(204, 42%, 42%);
  --accent-rgb: 72, 119, 148;
  --accent-gradient-end: hsl(205, 32%, 62%);
  --accent-muted: hsl(204, 28%, 38%);
  --accent-success: hsl(142, 45%, 48%);

  --text-primary: hsl(210, 20%, 96%);
  --text-secondary: hsl(210, 14%, 70%);
  --text-muted: hsl(210, 10%, 50%);

  --border-color: rgba(255, 255, 255, 0.07);
  --border-glow: rgba(72, 119, 148, 0.12);

  --header-bg: hsla(220, 18%, 7%, 0.85);
  --footer-bg: hsl(220, 18%, 5%);
  --hero-glow: hsla(204, 42%, 48%, 0.03);
  --sandbox-glow: hsla(204, 42%, 48%, 0.015);
  --surface-overlay: rgba(0, 0, 0, 0.15);
  --surface-overlay-light: rgba(0, 0, 0, 0.05);
  --surface-overlay-subtle: rgba(0, 0, 0, 0.1);
  --surface-inset: rgba(255, 255, 255, 0.02);
  --surface-hover: rgba(255, 255, 255, 0.02);
  --shadow-color: rgba(0, 0, 0, 0.3);
  --card-inset-highlight: rgba(255, 255, 255, 0.05);
  --btn-primary-text: hsl(220, 18%, 7%);
  --btn-action-hover-text: hsl(220, 18%, 7%);
  --noise-opacity: 0.025;
  --theme-switcher-bg: rgba(255, 255, 255, 0.04);
}

[data-theme="light"] {
  color-scheme: light;

  --bg-dark: hsl(210, 18%, 97%);
  --bg-panel: hsla(210, 14%, 100%, 0.85);
  --bg-panel-hover: hsl(210, 14%, 94%);
  --bg-input: hsl(210, 12%, 96%);

  --accent: hsl(204, 42%, 38%);
  --accent-hover: hsl(204, 42%, 32%);
  --accent-rgb: 56, 98, 124;
  --accent-gradient-end: hsl(205, 32%, 48%);
  --accent-muted: hsl(204, 22%, 42%);
  --accent-success: hsl(142, 40%, 36%);

  --text-primary: hsl(220, 18%, 12%);
  --text-secondary: hsl(220, 10%, 38%);
  --text-muted: hsl(220, 8%, 52%);

  --border-color: rgba(0, 0, 0, 0.08);
  --border-glow: rgba(56, 98, 124, 0.1);

  --header-bg: hsla(210, 18%, 97%, 0.9);
  --footer-bg: hsl(210, 14%, 94%);
  --hero-glow: hsla(204, 42%, 38%, 0.06);
  --sandbox-glow: hsla(204, 42%, 38%, 0.03);
  --surface-overlay: rgba(0, 0, 0, 0.03);
  --surface-overlay-light: rgba(0, 0, 0, 0.02);
  --surface-overlay-subtle: rgba(0, 0, 0, 0.04);
  --surface-inset: rgba(0, 0, 0, 0.02);
  --surface-hover: rgba(0, 0, 0, 0.03);
  --shadow-color: rgba(0, 0, 0, 0.08);
  --card-inset-highlight: rgba(255, 255, 255, 0.6);
  --btn-primary-text: hsl(210, 18%, 98%);
  --btn-action-hover-text: hsl(210, 18%, 98%);
  --noise-opacity: 0.018;
  --theme-switcher-bg: rgba(0, 0, 0, 0.04);
}

/* Reset & Globals */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  background-color: var(--bg-dark);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
}

body {
  overflow-x: hidden;
  min-height: 100vh;
}

/* Tactical Noise Overlay for premium matte feel */
.noise-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 9999;
  pointer-events: none;
  opacity: var(--noise-opacity);
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3联%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
}

/* Typography Extensions */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.02em;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-smooth);
}

/* Layout Containers */
.header-container,
.hero-container,
.section-container,
.footer-container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Custom Navigation Bar */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--header-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 1.25rem 0;
  transition: var(--transition-smooth);
}

.header-container {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.logo {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: 0.625rem;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: -0.03em;
}

.logo-mark {
  flex-shrink: 0;
  display: block;
  border-radius: var(--radius-sharp);
  box-shadow: 0 0 16px rgba(var(--accent-rgb), 0.15);
}

.nav {
  display: flex;
  align-items: center;
  gap: 2rem;
  margin-left: auto;
}

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
}

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

.nav-cta {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sharp);
}

.nav-cta:hover {
  border-color: var(--accent);
  background-color: rgba(var(--accent-rgb), 0.05);
  box-shadow: 0 0 15px rgba(var(--accent-rgb), 0.1);
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
}

.mobile-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  transition: var(--transition-smooth);
}

/* Hero Landing Section */
.hero {
  position: relative;
  padding: 8rem 0 6rem 0;
  background: radial-gradient(circle at 70% 30%, var(--hero-glow) 0%, transparent 60%);
  border-bottom: 1px solid var(--border-color);
}

.hero-container {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  align-items: center;
  gap: 4rem;
}

.badge-wrapper {
  margin-bottom: 1.5rem;
}

.hero-badge {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background-color: rgba(var(--accent-rgb), 0.08);
  border: 1px solid rgba(var(--accent-rgb), 0.25);
  color: var(--accent);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sharp);
  box-shadow: 0 0 10px rgba(var(--accent-rgb), 0.05);
}

.hero-title {
  font-size: 3.5rem;
  line-height: 1.15;
  margin-bottom: 1.5rem;
  font-weight: 700;
}

.hero-title .highlight {
  color: var(--text-primary);
  background: linear-gradient(120deg, var(--accent) 0%, var(--accent-gradient-end) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  max-width: 540px;
}

.hero-actions {
  display: flex;
  gap: 1rem;
}

/* Button UI Components */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sharp);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.btn-primary {
  background-color: var(--accent);
  color: var(--btn-primary-text);
  border: 1px solid var(--accent);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  box-shadow: 0 0 20px rgba(var(--accent-rgb), 0.18);
}

.btn-secondary {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
}

.btn-secondary:hover {
  background-color: var(--bg-panel-hover);
  border-color: var(--text-muted);
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.8rem;
}

/* Interactive Code Panel visual in Hero */
.hero-visual {
  position: relative;
}

.visual-card {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sharp);
  box-shadow: 0 20px 40px var(--shadow-color), inset 0 1px 0 var(--card-inset-highlight);
  overflow: hidden;
  backdrop-filter: blur(12px);
}

.card-header {
  background-color: var(--surface-inset);
  border-bottom: 1px solid var(--border-color);
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--text-muted);
}

.dot:nth-child(1) { background-color: #ef4444; }
.dot:nth-child(2) { background-color: #eab308; }
.dot:nth-child(3) { background-color: #22c55e; }

.card-title {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-left: 0.5rem;
}

.card-body {
  padding: 1.5rem;
}

pre {
  margin: 0;
}

code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.text-glow {
  color: var(--accent);
  text-shadow: 0 0 8px rgba(var(--accent-rgb), 0.2);
}

.text-success {
  color: var(--accent-success);
}

/* Ecosystem Grid Section */
.ecosystem {
  padding: 8rem 0;
  border-bottom: 1px solid var(--border-color);
}

.section-header {
  text-align: center;
  margin-bottom: 4.5rem;
}

.section-title {
  font-size: 2.25rem;
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.card {
  background-color: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sharp);
  padding: 2.25rem;
  transition: var(--transition-smooth);
  backdrop-filter: blur(12px);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--accent) 0%, transparent 100%);
  opacity: 0;
  transition: var(--transition-smooth);
}

.card:hover {
  border-color: rgba(var(--accent-rgb), 0.2);
  background-color: var(--bg-panel-hover);
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2), 0 0 20px rgba(var(--accent-rgb), 0.03);
}

.card:hover::before {
  opacity: 1;
}

.repo-icon {
  font-size: 1.75rem;
  margin-bottom: 1.5rem;
}

.card-heading {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  font-family: var(--font-sans);
  font-weight: 600;
}

.card-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1.75rem;
  line-height: 1.6;
}

.card-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
}

.card-link:hover {
  color: var(--text-primary);
}

/* Interactive Sandbox Widget */
.sandbox {
  padding: 8rem 0;
  border-bottom: 1px solid var(--border-color);
  background: radial-gradient(circle at 10% 50%, var(--sandbox-glow) 0%, transparent 50%);
}

.sandbox-widget {
  display: grid;
  grid-template-columns: 1fr 2.5fr;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sharp);
  background-color: var(--bg-panel);
  overflow: hidden;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

.sandbox-sidebar {
  border-right: 1px solid var(--border-color);
  background-color: var(--surface-overlay);
  padding: 1.5rem;
}

.sidebar-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.sidebar-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.sandbox-option {
  background: none;
  border: 1px solid transparent;
  text-align: left;
  padding: 1rem;
  cursor: pointer;
  transition: var(--transition-smooth);
  border-radius: var(--radius-sharp);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.sandbox-option:hover {
  background-color: var(--surface-hover);
  border-color: var(--border-color);
}

.sandbox-option.active {
  background-color: var(--bg-panel-hover);
  border-color: rgba(var(--accent-rgb), 0.2);
  box-shadow: inset 2px 0 0 var(--accent);
}

.option-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.option-desc {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.sandbox-content {
  display: flex;
  flex-direction: column;
}

.panel-header {
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--surface-overlay-light);
}

.panel-title {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.95rem;
}

.sandbox-code-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  flex-grow: 1;
}

.code-panel {
  padding: 1.5rem;
  overflow: auto;
  position: relative;
  min-height: 250px;
}

.code-panel:first-child {
  border-right: 1px solid var(--border-color);
}

.code-panel-label {
  position: absolute;
  top: 0.75rem;
  right: 1rem;
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.panel-output {
  background-color: var(--surface-overlay-subtle);
}

.panel-output code {
  transition: opacity 0.15s ease-in-out;
}

.panel-output.updating code {
  opacity: 0.4;
}

.btn-action {
  background-color: rgba(var(--accent-rgb), 0.1);
  color: var(--accent);
  border: 1px solid rgba(var(--accent-rgb), 0.3);
}

.btn-action:hover {
  background-color: var(--accent);
  color: var(--btn-action-hover-text);
  box-shadow: 0 0 15px rgba(var(--accent-rgb), 0.15);
}

/* Installation Tabs Section */
.install {
  padding: 8rem 0;
  border-bottom: 1px solid var(--border-color);
}

.install-tabs {
  max-width: 680px;
  margin: 0 auto;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sharp);
  background-color: var(--bg-panel);
  overflow: hidden;
  box-shadow: 0 15px 35px rgba(0,0,0,0.25);
}

.tabs-header {
  display: flex;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--surface-overlay-subtle);
}

.tab-btn {
  flex: 1;
  background: none;
  border: none;
  padding: 1rem;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.tab-btn:hover {
  color: var(--text-primary);
  background-color: var(--surface-hover);
}

.tab-btn.active {
  color: var(--accent);
  background-color: var(--bg-panel-hover);
  border-bottom: 2px solid var(--accent);
}

.tabs-content {
  padding: 2rem;
  background-color: var(--surface-overlay-light);
}

.tab-pane {
  display: none;
}

.tab-pane.active {
  display: block;
}

.tab-pane pre {
  margin: 0;
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sharp);
  padding: 1.25rem;
  overflow-x: auto;
}

.tab-pane code {
  color: var(--text-primary);
  font-size: 0.9rem;
}

/* Elegant Footers */
.footer {
  background-color: var(--footer-bg);
  border-top: 1px solid var(--border-color);
  padding: 5rem 0;
}

.footer-container {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 3rem;
}

.footer-left {
  flex: 1.5;
  min-width: 250px;
}

.footer-copy {
  margin-top: 1.25rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer-right {
  display: flex;
  gap: 4rem;
  flex-wrap: wrap;
}

.footer-column {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-column h4 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.footer-column a {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.footer-column a:hover {
  color: var(--accent);
}

/* Theme mode switcher */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.theme-switcher {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 3px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sharp);
  background-color: var(--theme-switcher-bg);
}

.theme-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0;
  border: none;
  border-radius: var(--radius-sharp);
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.theme-btn:hover {
  color: var(--text-secondary);
  background-color: var(--surface-hover);
}

.theme-btn.active {
  color: var(--accent);
  background-color: rgba(var(--accent-rgb), 0.12);
}

.theme-btn svg {
  width: 1rem;
  height: 1rem;
  fill: currentColor;
}

/* Responsive Grid and Mobile Layout System */
@media (max-width: 991px) {
  .hero-container {
    grid-template-columns: 1fr;
    gap: 3rem;
    text-align: center;
  }
  
  .hero-subtitle {
    margin-left: auto;
    margin-right: auto;
  }
  
  .hero-actions {
    justify-content: center;
  }
  
  .sandbox-widget {
    grid-template-columns: 1fr;
  }
  
  .sandbox-sidebar {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .sandbox-code-container {
    grid-template-columns: 1fr;
  }
  
  .code-panel:first-child {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
}

@media (max-width: 767px) {
  .hero-title {
    font-size: 2.5rem;
  }
  
  .mobile-toggle {
    display: flex;
  }

  .header-actions {
    margin-left: auto;
  }

  .nav {
    margin-left: 0;
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background-color: var(--bg-dark);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 2rem;
    gap: 1.5rem;
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
  }
  
  .nav.open {
    display: flex;
  }
  
  .footer-container {
    flex-direction: column;
    gap: 2.5rem;
  }
  
  .footer-right {
    gap: 2.5rem;
    width: 100%;
    justify-content: space-between;
  }
}