/* ===== CSS Variables ===== */
:root {
  --color-primary: #1a365d;
  --color-primary-light: #2b6cb0;
  --color-primary-lighter: #3182ce;
  --color-accent: #38b2ac;
  --color-accent-light: #4fd1c5;
  --color-bg: #f7fafc;
  --color-bg-white: #ffffff;
  --color-text: #2d3748;
  --color-text-light: #718096;
  --color-text-lighter: #a0aec0;
  --color-border: #e2e8f0;
  --color-border-light: #edf2f7;
  --color-code-bg: #1a202c;
  --color-code-text: #e2e8f0;
  --color-highlight: #ebf8ff;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
  --radius: 8px;
  --max-width: 1200px;
}

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

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

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-primary-light); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--color-primary-lighter); }

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

/* ===== Navigation ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.nav-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: #fff;
  font-weight: 700;
  font-size: 1.25rem;
  text-decoration: none;
}

.nav-brand:hover { color: #fff; }

.nav-brand svg { width: 32px; height: 32px; }

.nav-links { display: flex; gap: 0.125rem; list-style: none; white-space: nowrap; }

.nav-links a {
  color: rgba(255,255,255,0.85);
  padding: 0.375rem 0.625rem;
  border-radius: var(--radius);
  font-size: 0.8rem;
  font-weight: 500;
  transition: all 0.2s;
  white-space: nowrap;
}

.nav-links a:hover, .nav-links a.active {
  color: #fff;
  background: rgba(255,255,255,0.1);
}

.nav-github {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: rgba(255,255,255,0.85);
  padding: 0.5rem 1rem;
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.2s;
}

.nav-github:hover {
  color: #fff;
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.5);
}

.nav-github svg { width: 18px; height: 18px; fill: currentColor; }

/* Mobile nav */
.nav-toggle { display: none; background: none; border: none; color: white; cursor: pointer; padding: 0.5rem; }
.nav-toggle svg { width: 24px; height: 24px; }

@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--color-primary);
    flex-direction: column;
    padding: 1rem;
    box-shadow: var(--shadow-lg);
  }
  .nav-links.open { display: flex; }
  .nav-github { display: none; }
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, #1a365d 50%, #0d1b2a 100%);
  color: #fff;
  padding: 6rem 2rem 5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 30% 50%, rgba(56,178,172,0.15) 0%, transparent 50%),
              radial-gradient(circle at 70% 80%, rgba(49,130,206,0.1) 0%, transparent 50%);
  animation: heroGlow 15s ease-in-out infinite;
}

@keyframes heroGlow {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(-2%, -1%); }
}

.hero-content { position: relative; z-index: 1; max-width: 800px; margin: 0 auto; }

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
  line-height: 1.1;
}

.hero-acronym {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-accent-light);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: rgba(255,255,255,0.8);
  max-width: 600px;
  margin: 0 auto 2.5rem;
  line-height: 1.6;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.2s;
  cursor: pointer;
  border: none;
}

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

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

.btn-secondary {
  background: rgba(255,255,255,0.1);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.3);
}

.btn-secondary:hover { background: rgba(255,255,255,0.2); color: #fff; }

/* ===== Section ===== */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 4rem 2rem;
}

.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-header h2 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.75rem;
}

.section-header p {
  font-size: 1.1rem;
  color: var(--color-text-light);
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Cards ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: all 0.2s;
}

.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-lighter);
}

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--color-highlight);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
  color: var(--color-primary-light);
}

.card-icon svg { width: 24px; height: 24px; }

.card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

.card p {
  font-size: 0.95rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* ===== Stats Bar ===== */
.stats-bar {
  background: var(--color-bg-white);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding: 2rem;
}

.stats-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: center;
  gap: 4rem;
  flex-wrap: wrap;
}

.stat { text-align: center; }

.stat-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--color-primary);
  line-height: 1;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-top: 0.25rem;
  font-weight: 500;
}

/* ===== Diagram ===== */
.diagram-section {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem;
  margin: 2rem 0;
  text-align: center;
}

.diagram-section img {
  max-width: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.diagram-caption {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: var(--color-text-light);
  font-style: italic;
}

/* ===== Documentation Layout ===== */
.docs-layout {
  max-width: 1400px;
  margin: 0 auto;
  padding: 2rem;
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 3rem;
  min-height: calc(100vh - 64px);
}

@media (max-width: 900px) {
  .docs-layout {
    grid-template-columns: 1fr;
  }
  .docs-sidebar { display: none; }
}

/* Sidebar */
.docs-sidebar {
  position: sticky;
  top: 80px;
  height: fit-content;
  max-height: calc(100vh - 96px);
  overflow-y: auto;
  padding-right: 1rem;
}

.docs-sidebar::-webkit-scrollbar { width: 4px; }
.docs-sidebar::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 4px; }

.sidebar-section { margin-bottom: 1.5rem; }

.sidebar-section h4 {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-lighter);
  margin-bottom: 0.5rem;
  padding-left: 0.75rem;
}

.sidebar-section a {
  display: block;
  padding: 0.375rem 0.75rem;
  font-size: 0.875rem;
  color: var(--color-text-light);
  border-radius: 4px;
  border-left: 2px solid transparent;
  transition: all 0.15s;
}

.sidebar-section a:hover {
  color: var(--color-primary-light);
  background: var(--color-highlight);
}

.sidebar-section a.active {
  color: var(--color-primary-light);
  background: var(--color-highlight);
  border-left-color: var(--color-primary-light);
  font-weight: 600;
}

/* Docs Content */
.docs-content {
  min-width: 0;
  padding-bottom: 4rem;
}

.docs-content h1 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--color-border);
}

.docs-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-top: 3rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border-light);
}

.docs-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-text);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.docs-content h4 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text);
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.docs-content p {
  margin-bottom: 1rem;
  line-height: 1.7;
}

.docs-content ul, .docs-content ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.docs-content li { margin-bottom: 0.4rem; line-height: 1.6; }

.docs-content code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-border-light);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  color: var(--color-primary);
}

.docs-content pre {
  background: var(--color-code-bg);
  color: var(--color-code-text);
  padding: 1.25rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 1.5rem;
  font-size: 0.875rem;
  line-height: 1.6;
}

.docs-content pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.docs-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.9rem;
}

.docs-content th {
  background: var(--color-primary);
  color: #fff;
  padding: 0.75rem 1rem;
  text-align: left;
  font-weight: 600;
  font-size: 0.85rem;
}

.docs-content td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
}

.docs-content tr:nth-child(even) td { background: var(--color-border-light); }

.docs-content .callout {
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
  border-left: 4px solid;
}

.docs-content .callout-info {
  background: #ebf8ff;
  border-left-color: #3182ce;
}

.docs-content .callout-tip {
  background: #f0fff4;
  border-left-color: #38a169;
}

.docs-content .callout-warn {
  background: #fffaf0;
  border-left-color: #dd6b20;
}

.docs-content .callout strong {
  display: block;
  margin-bottom: 0.25rem;
}

/* ===== Tech Badge ===== */
.tech-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.tech-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.75rem;
  background: var(--color-highlight);
  color: var(--color-primary);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid var(--color-border);
}

/* ===== Architecture Diagram (ASCII-like) ===== */
.arch-box {
  background: var(--color-bg-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1rem;
  position: relative;
}

.arch-box h4 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  color: var(--color-primary);
}

.arch-box .layer-label {
  position: absolute;
  top: -0.6rem;
  left: 1rem;
  background: var(--color-bg);
  padding: 0 0.5rem;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-primary-light);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ===== Footer ===== */
.footer {
  background: var(--color-primary);
  color: rgba(255,255,255,0.7);
  padding: 3rem 2rem;
  margin-top: 4rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer a { color: rgba(255,255,255,0.85); }
.footer a:hover { color: #fff; }

.footer-links { display: flex; gap: 2rem; list-style: none; font-size: 0.9rem; }

.footer-copy { font-size: 0.85rem; }

/* ===== Utility ===== */
.text-center { text-align: center; }
.mt-2 { margin-top: 2rem; }
.mt-3 { margin-top: 3rem; }
.mb-2 { margin-bottom: 2rem; }