/* =============================================
   FLOWNET — Network Flow Platform
   Dark industrial aesthetic with neon accents
   ============================================= */

:root {
  --bg: #050709;
  --bg2: #0c0f14;
  --bg3: #12161e;
  --border: #1e2530;
  --accent: #00e5ff;
  --accent2: #ff5722;
  --accent3: #76ff03;
  --text: #e8edf5;
  --text2: #7a8899;
  --text3: #3a4555;
  --font-display: 'Syne', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-mono);
  overflow-x: hidden;
  line-height: 1.6;
}

/* Canvas Background */
#bgCanvas {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  pointer-events: none;
  z-index: 0;
  opacity: 0.35;
}

/* ---- NAV ---- */
.nav {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 100;
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  background: rgba(5,7,9,0.85);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 2rem;
}

.logo {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.3rem;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.1em;
}
.logo span { color: var(--accent); }

.nav-links {
  display: flex;
  list-style: none;
  gap: 0.25rem;
  margin-left: 2rem;
}

.nav-links a {
  color: var(--text2);
  text-decoration: none;
  font-size: 0.8rem;
  padding: 0.4rem 0.9rem;
  border-radius: 4px;
  transition: all 0.2s;
  letter-spacing: 0.05em;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--accent);
  background: rgba(0,229,255,0.08);
}

.nav-cta {
  margin-left: auto;
  background: var(--accent);
  color: #000;
  text-decoration: none;
  font-size: 0.78rem;
  font-weight: 500;
  padding: 0.45rem 1.1rem;
  border-radius: 4px;
  letter-spacing: 0.04em;
  transition: opacity 0.2s;
}
.nav-cta:hover { opacity: 0.85; }

.hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.4rem;
  cursor: pointer;
  margin-left: auto;
}

.mobile-menu {
  display: none;
  position: fixed;
  top: 60px; left: 0; right: 0;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 1rem 2rem;
  flex-direction: column;
  gap: 0.5rem;
  z-index: 99;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  color: var(--text2);
  text-decoration: none;
  font-size: 0.9rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
}

/* ---- HERO ---- */
.hero {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 8rem 2rem 4rem;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-block;
  font-size: 0.72rem;
  color: var(--accent);
  background: rgba(0,229,255,0.08);
  border: 1px solid rgba(0,229,255,0.25);
  padding: 0.35rem 0.9rem;
  border-radius: 2px;
  letter-spacing: 0.08em;
  margin-bottom: 2rem;
  width: fit-content;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(3.5rem, 10vw, 7.5rem);
  font-weight: 800;
  line-height: 0.92;
  letter-spacing: -0.03em;
  margin-bottom: 1.8rem;
}

.accent { color: var(--accent); text-shadow: 0 0 40px rgba(0,229,255,0.4); }

.hero-sub {
  font-size: 0.95rem;
  color: var(--text2);
  max-width: 480px;
  margin-bottom: 2.5rem;
  line-height: 1.8;
}

.hero-btns {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 4rem;
}

.btn-primary {
  background: var(--accent);
  color: #000;
  padding: 0.75rem 1.8rem;
  border-radius: 4px;
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
  transition: all 0.2s;
  border: none;
  cursor: pointer;
}
.btn-primary:hover { opacity: 0.85; transform: translateY(-1px); }
.btn-primary.large { padding: 1rem 2.5rem; font-size: 0.95rem; }

.btn-ghost {
  background: transparent;
  color: var(--text2);
  padding: 0.75rem 1.8rem;
  border-radius: 4px;
  text-decoration: none;
  font-size: 0.85rem;
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
  border: 1px solid var(--border);
  transition: all 0.2s;
  cursor: pointer;
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

.hero-stats {
  display: flex;
  gap: 3rem;
}
.stat {
  font-size: 0.78rem;
  color: var(--text2);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.stat span {
  display: block;
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
  margin-bottom: 0.2rem;
}

/* ---- SECTIONS ---- */
section { position: relative; z-index: 1; }

.section-label {
  font-size: 0.72rem;
  color: var(--accent);
  letter-spacing: 0.12em;
  margin-bottom: 0.75rem;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 3rem;
}

/* ---- FEATURES ---- */
.features {
  padding: 6rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
}

.feat-card {
  background: var(--bg2);
  padding: 2.5rem;
  position: relative;
  transition: background 0.3s;
}
.feat-card:hover { background: var(--bg3); }

.feat-large { grid-column: span 2; }
.feat-wide { grid-column: span 2; }

.feat-icon {
  font-size: 2rem;
  margin-bottom: 1.2rem;
  display: block;
  color: var(--accent);
  filter: drop-shadow(0 0 8px rgba(0,229,255,0.5));
}

.feat-card h3 {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.feat-card p {
  font-size: 0.83rem;
  color: var(--text2);
  line-height: 1.8;
}

.feat-tag {
  display: inline-block;
  margin-top: 1.5rem;
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent2);
  border: 1px solid rgba(255,87,34,0.3);
  padding: 0.2rem 0.6rem;
  border-radius: 2px;
}

/* ---- ALGORITHMS ---- */
.algo-section {
  padding: 6rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
  border-top: 1px solid var(--border);
}

.algo-list {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  margin-bottom: 2rem;
}

.algo-item {
  background: var(--bg2);
  display: flex;
  align-items: center;
  padding: 1.5rem 2rem;
  gap: 2rem;
  transition: background 0.25s;
  cursor: pointer;
  position: relative;
}
.algo-item::after {
  content: attr(data-complexity);
  position: absolute;
  right: 2rem;
  font-size: 0.72rem;
  color: var(--text3);
  letter-spacing: 0.04em;
}
.algo-item:hover { background: var(--bg3); }
.algo-item:hover .algo-name { color: var(--accent); }

.algo-num {
  font-size: 0.72rem;
  color: var(--text3);
  letter-spacing: 0.1em;
  min-width: 2rem;
}

.algo-name {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  transition: color 0.2s;
}

.algo-badge {
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.2rem 0.6rem;
  border-radius: 2px;
  background: var(--bg3);
  color: var(--text2);
  border: 1px solid var(--border);
}
.algo-badge.best {
  background: rgba(118,255,3,0.1);
  color: var(--accent3);
  border-color: rgba(118,255,3,0.3);
}

.view-all-link {
  color: var(--accent);
  text-decoration: none;
  font-size: 0.85rem;
  letter-spacing: 0.04em;
  transition: opacity 0.2s;
}
.view-all-link:hover { opacity: 0.7; }

/* ---- CTA ---- */
.cta-section {
  padding: 6rem 2rem;
  border-top: 1px solid var(--border);
  position: relative;
  z-index: 1;
}
.cta-inner {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}
.cta-inner h2 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}
.cta-inner p {
  color: var(--text2);
  font-size: 0.9rem;
  margin-bottom: 2rem;
  line-height: 1.8;
}

/* ---- FOOTER ---- */
.footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 2rem;
  position: relative;
  z-index: 1;
}
.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
}
.footer-logo {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.1rem;
  letter-spacing: 0.1em;
}
.footer-logo span { color: var(--accent); }
.footer-links {
  display: flex;
  gap: 1.5rem;
  margin-left: auto;
}
.footer-links a {
  color: var(--text2);
  text-decoration: none;
  font-size: 0.8rem;
  transition: color 0.2s;
}
.footer-links a:hover { color: var(--accent); }
.footer-copy {
  font-size: 0.72rem;
  color: var(--text3);
  width: 100%;
}

/* ---- PAGE INNER LAYOUTS ---- */
.page-header {
  padding: 7rem 2rem 3rem;
  max-width: 1200px;
  margin: 0 auto;
  border-bottom: 1px solid var(--border);
}
.page-header .section-label { margin-bottom: 0.5rem; }
.page-header h1 {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 7vw, 5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
}
.page-header p {
  color: var(--text2);
  margin-top: 1rem;
  font-size: 0.9rem;
  max-width: 550px;
  line-height: 1.8;
}

/* ---- VISUALIZER ---- */
.visualizer-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  height: calc(100vh - 60px);
  margin-top: 60px;
}

.sidebar {
  background: var(--bg2);
  border-right: 1px solid var(--border);
  padding: 1.5rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.sidebar-section h4 {
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text3);
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.sidebar-btn {
  width: 100%;
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.6rem 1rem;
  cursor: pointer;
  border-radius: 4px;
  text-align: left;
  transition: all 0.2s;
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.sidebar-btn:hover { border-color: var(--accent); color: var(--accent); }
.sidebar-btn.active { background: rgba(0,229,255,0.1); border-color: var(--accent); color: var(--accent); }

.select-input {
  width: 100%;
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.6rem 1rem;
  border-radius: 4px;
  cursor: pointer;
  outline: none;
}
.select-input:focus { border-color: var(--accent); }

.canvas-area {
  position: relative;
  background: var(--bg);
  overflow: hidden;
}

#flowCanvas {
  width: 100%;
  height: 100%;
  cursor: crosshair;
}

.canvas-toolbar {
  position: absolute;
  top: 1rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 0.5rem;
  background: var(--bg2);
  border: 1px solid var(--border);
  padding: 0.5rem;
  border-radius: 6px;
}

.tool-btn {
  background: none;
  border: 1px solid transparent;
  color: var(--text2);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.4rem 0.8rem;
  cursor: pointer;
  border-radius: 3px;
  transition: all 0.2s;
  white-space: nowrap;
}
.tool-btn:hover, .tool-btn.active {
  background: rgba(0,229,255,0.1);
  border-color: var(--accent);
  color: var(--accent);
}

.info-panel {
  position: absolute;
  bottom: 1rem;
  right: 1rem;
  background: var(--bg2);
  border: 1px solid var(--border);
  padding: 1.2rem 1.5rem;
  border-radius: 4px;
  min-width: 200px;
  font-size: 0.78rem;
}
.info-panel h5 {
  color: var(--text3);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.info-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.4rem;
  gap: 1rem;
}
.info-row span:last-child { color: var(--accent); }

/* ---- ALGORITHMS PAGE ---- */
.algo-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 3rem 2rem;
}

.algo-detail-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.algo-detail-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  padding: 2rem;
  border-radius: 4px;
}
.algo-detail-card h3 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}
.algo-detail-card .complexity {
  font-size: 0.8rem;
  color: var(--accent);
  margin-bottom: 1rem;
  font-family: var(--font-mono);
}
.algo-detail-card p {
  color: var(--text2);
  font-size: 0.82rem;
  line-height: 1.8;
}
.algo-detail-card .pros-cons {
  margin-top: 1.2rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  font-size: 0.78rem;
}
.pros-cons div:first-child { color: var(--accent3); }
.pros-cons div:last-child { color: var(--accent2); }

/* ---- DOCS PAGE ---- */
.docs-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  max-width: 1200px;
  margin: 0 auto;
  padding: 3rem 2rem;
  gap: 3rem;
  min-height: 80vh;
}

.docs-sidebar { position: sticky; top: 80px; height: fit-content; }
.docs-nav-item {
  display: block;
  color: var(--text2);
  text-decoration: none;
  font-size: 0.8rem;
  padding: 0.45rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.2s;
}
.docs-nav-item:hover { color: var(--accent); }
.docs-nav-item.category {
  color: var(--text3);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-top: 1.5rem;
  border-bottom: none;
  cursor: default;
}

.docs-content h2 {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}
.docs-content h3 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  margin: 2rem 0 0.75rem;
}
.docs-content p {
  color: var(--text2);
  font-size: 0.85rem;
  line-height: 1.9;
  margin-bottom: 1rem;
}

.code-block {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  padding: 1.5rem;
  border-radius: 4px;
  font-size: 0.8rem;
  line-height: 1.7;
  overflow-x: auto;
  margin: 1.5rem 0;
  white-space: pre;
  color: var(--accent3);
}

.docs-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.8rem;
}
.docs-table th {
  background: var(--bg2);
  padding: 0.75rem 1rem;
  text-align: left;
  color: var(--text3);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border-bottom: 2px solid var(--border);
}
.docs-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--text2);
}
.docs-table tr:hover td { background: var(--bg2); }

/* ---- RESPONSIVE ---- */
@media (max-width: 768px) {
  .nav-links, .nav-cta { display: none; }
  .hamburger { display: block; }
  .features-grid { grid-template-columns: 1fr; }
  .feat-large, .feat-wide { grid-column: span 1; }
  .visualizer-layout { grid-template-columns: 1fr; grid-template-rows: auto 1fr; }
  .sidebar { max-height: 250px; }
  .algo-detail-grid { grid-template-columns: 1fr; }
  .docs-layout { grid-template-columns: 1fr; }
  .docs-sidebar { display: none; }
  .hero-stats { gap: 1.5rem; flex-wrap: wrap; }
  .algo-item::after { display: none; }
  .footer-links { margin-left: 0; }
}

/* Animations */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
.hero > * {
  animation: fadeUp 0.6s ease both;
}
.hero-badge { animation-delay: 0.1s; }
.hero-title { animation-delay: 0.2s; }
.hero-sub { animation-delay: 0.3s; }
.hero-btns { animation-delay: 0.4s; }
.hero-stats { animation-delay: 0.5s; }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text3); }