:root{
  --bg: #1a202c;
  --panel: #2d3748;
  --surface: #4a5568;
  --text: #f7fafc;
  --muted: #a0aec0;
  --stroke: rgba(160,174,192,0.2);
  --accent: #4299e1;
  --accent-hover: #3182ce;
  --success: #48bb78;
  --shadow: rgba(0,0,0,0.4);
}

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

body{
  margin:0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background: linear-gradient(135deg, #2d3748 0%, #1a202c 50%, #2d3748 100%);
  min-height: 100vh;
  color: var(--text);
  line-height: 1.6;
  padding-top: env(safe-area-inset-top);
}

h3 {
  margin: 0 0 16px;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.3px;
  color: var(--text);
}

.topbar{
  position: sticky;
  top: 0;
  display: flex;
  gap: 20px;
  align-items: center;
  justify-content: space-between;
  padding: 18px 28px;
  background: rgba(45, 55, 72, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(160,174,192,0.15);
  box-shadow: 0 4px 20px rgba(0,0,0,0.3);
  z-index: 100;
}

.brand{
  font-weight: 800;
  letter-spacing: -0.5px;
  font-size: 24px;
  color: #4299e1;
  text-shadow: 0 0 20px rgba(66,153,225,0.5);
}

.controls{
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
}

.controls label{
  display: flex;
  gap: 8px;
  align-items: center;
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
}

.controls input[type="text"]{
  width: 220px;
  padding: 12px 16px;
  border-radius: 10px;
  border: 1px solid rgba(160,174,192,0.25);
  background: rgba(74,85,104,0.4);
  color: var(--text);
  outline: none;
  transition: all 0.3s ease;
  font-size: 14px;
}

.controls input[type="text"]:focus{
  border-color: var(--accent);
  background: rgba(74,85,104,0.6);
  box-shadow: 0 0 0 4px rgba(66,153,225,0.15);
  transform: translateY(-1px);
}

.controls button{
  padding: 12px 24px;
  border-radius: 10px;
  border: none;
  background: linear-gradient(135deg, #4299e1 0%, #3182ce 100%);
  color: #ffffff;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  transition: all 0.3s ease;
  box-shadow: 0 4px 14px rgba(66,153,225,0.4);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.controls button.secondary{
  background: linear-gradient(135deg, rgba(74,85,104,0.6) 0%, rgba(45,55,72,0.6) 100%);
  box-shadow: 0 2px 8px rgba(0,0,0,0.25);
}

.controls button:hover{
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(66,153,225,0.5);
}

.controls button.secondary:hover{
  background: linear-gradient(135deg, rgba(74,85,104,0.8) 0%, rgba(45,55,72,0.8) 100%);
  box-shadow: 0 4px 16px rgba(0,0,0,0.35);
}

.controls button:active{
  transform: translateY(0);
}

.checkbox{
  user-select: none;
  display: flex;
  gap: 8px;
  align-items: center;
  color: var(--muted);
  font-size: 14px;
  cursor: pointer;
}

.checkbox input[type="checkbox"]{
  width: 18px;
  height: 18px;
  cursor: pointer;
}

main{
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 24px;
  padding: 24px;
  max-width: 1400px;
  margin: 0 auto;
}

.canvasWrap{
  background: linear-gradient(135deg, rgba(45,55,72,0.4) 0%, rgba(26,32,44,0.6) 100%);
  border: 1px solid rgba(160,174,192,0.2);
  border-radius: 16px;
  padding: 40px;
  overflow: auto;
  box-shadow: 0 20px 40px rgba(0,0,0,0.25),
              0 4px 12px rgba(0,0,0,0.15),
              inset 0 1px 0 rgba(160,174,192,0.1);
}

#board{
  display: block;
  margin: 0 auto;
  width: 100%;
  max-width: 1100px;
  height: auto;
}

.sidebar{
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.panel{
  background: linear-gradient(135deg, rgba(74,85,104,0.4) 0%, rgba(45,55,72,0.5) 100%);
  border: 1px solid rgba(160,174,192,0.2);
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.2),
              inset 0 1px 0 rgba(160,174,192,0.1);
  transition: all 0.3s ease;
}

.panel:hover{
  border-color: rgba(66,153,225,0.3);
  box-shadow: 0 12px 32px rgba(0,0,0,0.25);
}

.legendGrid{
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.legendItem{
  display: flex;
  gap: 12px;
  align-items: center;
  padding: 12px 16px;
  border: 1px solid rgba(160,174,192,0.15);
  border-radius: 10px;
  background: rgba(74,85,104,0.25);
  color: var(--muted);
  font-size: 14px;
  transition: all 0.3s ease;
  cursor: default;
}

.legendItem:hover{
  background: rgba(74,85,104,0.4);
  border-color: rgba(66,153,225,0.4);
  transform: translateX(4px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.swatch{
  width: 24px;
  height: 24px;
  border-radius: 6px;
  border: 2px solid rgba(160,174,192,0.3);
  box-shadow: 0 2px 8px rgba(0,0,0,0.2), inset 0 1px 2px rgba(255,255,255,0.1);
}

.selectRow{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
  font-size: 14px;
  margin: 8px 0 12px;
  font-weight: 500;
}

select{
  padding: 11px 16px;
  border-radius: 10px;
  border: 1px solid rgba(160,174,192,0.25);
  background: rgba(74,85,104,0.4);
  color: var(--text);
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 14px;
}

select:hover{
  background: rgba(74,85,104,0.6);
  border-color: rgba(160,174,192,0.35);
}

select:focus{
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(66,153,225,0.15);
}

.optList{
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 12px 0;
}

.hint{
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
  margin: 16px 0 0;
  padding: 14px;
  background: rgba(66,153,225,0.08);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
}

/* Mobile responsive styles */
@media (max-width: 1024px) {
  main {
    grid-template-columns: 1fr;
    padding: 12px;
    gap: 16px;
  }

  .topbar {
    flex-direction: column;
    gap: 12px;
    align-items: stretch;
    padding: 16px;
  }

  .brand {
    text-align: center;
    font-size: 20px;
  }

  .controls {
    flex-direction: column;
    gap: 10px;
  }

  .controls label {
    width: 100%;
  }

  .controls input[type="text"] {
    width: 100%;
  }

  .controls button {
    width: 100%;
    padding: 14px;
    font-size: 15px;
  }

  /* Board first on mobile */
  .canvasWrap {
    order: 1;
    overflow: auto;
    border-radius: 12px;
    padding: 12px;
    -webkit-overflow-scrolling: touch;
    margin-bottom: 0;
    max-height: 70vh;
  }

  #board {
    width: 100%;
    height: auto;
    min-width: auto;
    max-height: 65vh;
  }

  /* Sidebar second on mobile */
  .sidebar {
    order: 2;
  }

  .panel {
    padding: 16px;
  }

  h3 {
    font-size: 16px;
    margin-bottom: 12px;
  }
}

@media (max-width: 640px) {
  .topbar {
    padding: 12px;
  }

  main {
    padding: 8px;
    gap: 12px;
  }

  .canvasWrap {
    padding: 8px;
    max-height: 65vh;
  }

  #board {
    max-height: 60vh;
  }

  .panel {
    padding: 16px;
  }

  h3 {
    font-size: 17px;
    margin: 0 0 12px;
  }

  .canvasWrap {
    padding: 16px;
  }
}