:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface2: #21262d;
  --border: #30363d;
  --accent: #f0b429;
  --accent2: #e07b00;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --success: #3fb950;
  --info: #58a6ff;
  --danger: #f85149;
  --radius: 8px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
}

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

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* Header */
header {
  background: linear-gradient(135deg, #1a1f2e 0%, #0d1117 50%, #1a1210 100%);
  border-bottom: 2px solid var(--accent);
  padding: 24px 0;
}
.header-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 24px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 6px;
}
.logo-icon { font-size: 36px; }
h1 {
  font-size: 2rem;
  font-weight: 700;
  background: linear-gradient(90deg, var(--accent), #ff9a00);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.subtitle { color: var(--text-muted); font-size: 0.95rem; }

/* Main */
main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

/* Cards */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}
.card h2 {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 20px;
  color: var(--accent);
}
.card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text);
}

/* Planner Controls */
.planner-controls {
  display: flex;
  gap: 16px;
  align-items: flex-end;
  flex-wrap: wrap;
}
.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.control-group label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}
select, input[type="number"] {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  padding: 10px 14px;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s;
}
select { min-width: 280px; cursor: pointer; }
input[type="number"] { width: 130px; }
select:focus, input:focus { border-color: var(--accent); }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #000;
  border: none;
  border-radius: var(--radius);
  padding: 10px 28px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
  white-space: nowrap;
}
.btn-primary:hover { opacity: 0.88; transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }

/* Results Grid */
.hidden { display: none !important; }
.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
  margin-bottom: 20px;
}
.chain-card { margin-top: 0; }

/* Material Items */
.material-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  background: var(--surface2);
  border-radius: 6px;
  margin-bottom: 8px;
  border-left: 3px solid var(--info);
}
.material-item.raw { border-left-color: var(--success); }
.material-item.machine { border-left-color: var(--accent); }
.material-icon { font-size: 1.4rem; }
.material-name { font-weight: 500; flex: 1; }
.material-amount {
  font-size: 0.85rem;
  color: var(--text-muted);
  background: var(--bg);
  padding: 2px 8px;
  border-radius: 12px;
  font-weight: 600;
}

/* Tree Visualization */
#tree-container {
  overflow-x: auto;
  padding: 8px 0;
}
.tree-node {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  position: relative;
}
.tree-row {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  justify-content: center;
}
.node-box {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 16px;
  text-align: center;
  min-width: 120px;
  position: relative;
  transition: border-color 0.2s;
}
.node-box:hover { border-color: var(--accent); }
.node-box.root { border-color: var(--accent); background: rgba(240,180,41,0.1); }
.node-box.raw-node { border-color: var(--success); background: rgba(63,185,80,0.08); }
.node-icon { font-size: 1.6rem; display: block; }
.node-name { font-size: 0.8rem; font-weight: 600; margin-top: 4px; }
.node-rate { font-size: 0.72rem; color: var(--text-muted); margin-top: 2px; }
.node-machine { font-size: 0.68rem; color: var(--accent); margin-top: 3px; }

.connector {
  width: 2px;
  background: var(--border);
  height: 24px;
  margin: 0 auto;
}
.horizontal-connector {
  display: flex;
  align-items: center;
}

/* Tree layout using CSS */
.tree-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 16px;
  gap: 0;
}
.tree-level {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  position: relative;
}
.tree-branch {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.branch-children {
  display: flex;
  gap: 16px;
  margin-top: 0;
}
.branch-connector {
  width: 2px;
  height: 20px;
  background: var(--border);
  margin: 0 auto;
}
.children-bar {
  height: 2px;
  background: var(--border);
  align-self: stretch;
}

/* Suggestions */
.section-desc {
  color: var(--text-muted);
  margin-bottom: 20px;
  font-size: 0.9rem;
}
.suggestion-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}
.suggestion-card {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  cursor: pointer;
  transition: border-color 0.2s, transform 0.15s;
  text-align: center;
}
.suggestion-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}
.suggestion-icon { font-size: 2rem; display: block; margin-bottom: 8px; }
.suggestion-name { font-weight: 600; font-size: 0.9rem; }
.suggestion-tier {
  display: inline-block;
  margin-top: 6px;
  font-size: 0.72rem;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(240,180,41,0.15);
  color: var(--accent);
}

/* Recipe Grid */
.filter-bar {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.filter-input {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  padding: 8px 14px;
  font-size: 0.9rem;
  outline: none;
  flex: 1;
  min-width: 200px;
}
.filter-input:focus { border-color: var(--accent); }
.tier-filters { display: flex; gap: 8px; }
.tier-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-muted);
  padding: 6px 14px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.2s;
}
.tier-btn.active, .tier-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(240,180,41,0.1);
}

.recipe-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 14px;
}
.recipe-card {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  transition: border-color 0.2s;
}
.recipe-card:hover { border-color: var(--accent); }
.recipe-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}
.recipe-icon { font-size: 1.8rem; }
.recipe-title { font-weight: 600; font-size: 0.95rem; }
.recipe-machine-label {
  font-size: 0.75rem;
  color: var(--accent);
  background: rgba(240,180,41,0.1);
  padding: 2px 7px;
  border-radius: 8px;
  margin-left: auto;
}
.recipe-ingredients {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 10px;
}
.ingredient-tag {
  font-size: 0.78rem;
  padding: 3px 8px;
  border-radius: 8px;
  background: rgba(88,166,255,0.1);
  color: var(--info);
  border: 1px solid rgba(88,166,255,0.2);
}
.recipe-arrow { color: var(--text-muted); font-size: 1rem; margin: 0 4px; }
.recipe-output-tag {
  font-size: 0.78rem;
  padding: 3px 8px;
  border-radius: 8px;
  background: rgba(63,185,80,0.1);
  color: var(--success);
  border: 1px solid rgba(63,185,80,0.2);
  font-weight: 600;
}
.recipe-stats {
  display: flex;
  gap: 10px;
  font-size: 0.75rem;
  color: var(--text-muted);
}
.tier-badge {
  font-size: 0.7rem;
  padding: 2px 6px;
  border-radius: 6px;
  font-weight: 700;
}
.tier-1 { background: rgba(63,185,80,0.15); color: var(--success); }
.tier-2 { background: rgba(88,166,255,0.15); color: var(--info); }
.tier-3 { background: rgba(240,180,41,0.15); color: var(--accent); }

footer {
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 20px;
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-top: 40px;
}