/* ── Global ── */
* { font-family: 'Sarabun', sans-serif; }
code, .mono { font-family: 'JetBrains Mono', monospace; }

body {
  box-sizing: border-box;
  background-color: #f8fafc;
  color: #0f172a;
}

/* ── Navbar ── */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 56px;
  display: flex;
  align-items: center;
  padding: 0 1.5rem;
  gap: 0.5rem;
  background: #ffffff;
  border-bottom: 1px solid #e2e8f0;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.site-nav .logo {
  font-size: 1rem;
  font-weight: 700;
  color: #0f172a;
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.site-nav .logo span { color: #3b82f6; }

.site-nav .sep {
  color: #cbd5e1;
  font-size: 1rem;
  user-select: none;
}

.site-nav .crumb {
  font-size: 0.85rem;
  color: #64748b;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ── Animations ── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes slideIn {
  from { opacity: 0; transform: translateX(-40px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes nodePulse {
  0%   { transform: scale(1); box-shadow: 0 0 0 0 currentColor; }
  50%  { transform: scale(1.15); }
  100% { transform: scale(1); box-shadow: 0 0 0 15px transparent; }
}
@keyframes nodeGlow {
  0%, 100% { filter: brightness(1) drop-shadow(0 0 8px currentColor); }
  50%       { filter: brightness(1.2) drop-shadow(0 0 16px currentColor); }
}
@keyframes edgeFlow {
  0% {
    background: linear-gradient(90deg, transparent, currentColor, transparent);
    background-size: 200% 100%;
    background-position: 200% center;
  }
  100% {
    background: linear-gradient(90deg, transparent, currentColor, transparent);
    background-size: 200% 100%;
    background-position: -200% center;
  }
}
@keyframes pathHighlight {
  0%   { opacity: 0; }
  100% { opacity: 1; }
}

.fade-up     { animation: fadeUp 0.7s ease forwards; opacity: 0; }
.slide-in    { animation: slideIn 0.6s ease forwards; opacity: 0; }
.node-active { animation: nodePulse 0.8s ease-out !important; }
.node-glow   { animation: nodeGlow 1.2s ease-in-out infinite !important; }
.edge-active { animation: edgeFlow 1s ease-in-out !important; }
.path-active { animation: pathHighlight 0.4s ease forwards !important; }

/* ── Graph ── */
.graph-node {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 16px;
  transition: all 0.2s;
  cursor: pointer;
  position: absolute;
  will-change: transform;
  z-index: 10;
}

.graph-edge {
  position: absolute;
  height: 3px;
  transform-origin: left center;
  transition: background 0.3s;
  z-index: 1;
}

/* ── Tabs ── */
.tab-btn { transition: all 0.3s; }
.tab-btn.active {
  transform: translateY(-2px);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
}

/* ── ตัวเลือกโหนด Start / Goal ── */
.algo-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1.25rem;
  margin-bottom: 1.25rem;
}
.algo-controls label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: #475569;
  font-weight: 600;
}
.algo-select {
  padding: 0.45rem 0.75rem;
  border-radius: 0.6rem;
  border: 1px solid #cbd5e1;
  background: #ffffff;
  color: #0f172a;
  font-weight: 700;
  font-size: 0.85rem;
  cursor: pointer;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.algo-select:focus {
  outline: none;
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.18);
}

/* ── กล่องผลลัพธ์ (เลียนแบบ console ของ Python) ── */
.algo-result {
  border-radius: 0.75rem;
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
  background: #0f172a;
  color: #e2e8f0;
  line-height: 1.6;
  word-break: break-word;
}
.algo-result .label { color: #94a3b8; }
.algo-result .sol   { font-weight: 700; color: #fff; }

/* ── จุดเริ่มต้น (เขียว) / เป้าหมาย (แดง) ── */
.node-start { box-shadow: 0 0 0 4px #10b981 !important; }
.node-goal  { box-shadow: 0 0 0 4px #ef4444 !important; }