/* Import Google Font */
@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@400;500;700&display=swap');

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

/* Base styling */
html, body {
  height: 100%;
  font-family: 'Roboto', sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
}

/* Header */
header {
  background: rgba(0, 0, 0, 0.3);
  text-align: center;
  padding: 30px 20px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

header h1 {
  font-size: 2.5rem;
  margin-bottom: 10px;
}

header p {
  font-size: 1.1rem;
  opacity: 0.9;
}

/* Main content */
main {
  display: flex;
  max-width: 1200px;
  margin: 40px auto;
  gap: 30px;
  padding: 0 20px;
  flex-wrap: wrap;
  justify-content: center;
}

/* Controls Panel */
.controls-panel {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 15px;
  padding: 25px;
  min-width: 300px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.control-group {
  margin-bottom: 20px;
}

.control-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  font-size: 1rem;
}

.control-group select,
.control-group input[type="range"] {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: none;
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
  font-size: 1rem;
}

.control-group select {
  cursor: pointer;
}

.control-group select option {
  background: #764ba2;
  color: #fff;
}

.control-group input[type="range"] {
  padding: 0;
  height: 8px;
  cursor: pointer;
}

#shapeCountValue {
  display: inline-block;
  margin-left: 10px;
  font-weight: 700;
  font-size: 1.2rem;
}

button {
  width: 100%;
  padding: 12px 20px;
  margin-top: 10px;
  background: rgba(255, 255, 255, 0.3);
  border: 2px solid rgba(255, 255, 255, 0.5);
  border-radius: 8px;
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
}

button:hover {
  background: rgba(255, 255, 255, 0.5);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

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

#packBtn {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  border: none;
}

#packBtn:hover {
  background: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
}

/* Info Panel */
.info-panel {
  margin-top: 30px;
  padding: 20px;
  background: rgba(0, 0, 0, 0.2);
  border-radius: 10px;
}

.info-panel h3 {
  margin-bottom: 15px;
  font-size: 1.3rem;
}

.info-panel p {
  margin-bottom: 8px;
  font-size: 1rem;
}

/* Canvas Container */
.canvas-container {
  background: rgba(255, 255, 255, 0.95);
  border-radius: 15px;
  padding: 20px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

#packingCanvas {
  display: block;
  border: 2px solid #667eea;
  border-radius: 10px;
  background: white;
}

/* Footer */
footer {
  text-align: center;
  padding: 30px 20px;
  margin-top: 40px;
  background: rgba(0, 0, 0, 0.3);
}

footer p {
  margin-bottom: 10px;
  font-size: 1rem;
}

footer a {
  color: #fff;
  text-decoration: none;
  padding: 10px 20px;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 8px;
  display: inline-block;
  transition: all 0.3s ease;
}

footer a:hover {
  background: rgba(255, 255, 255, 0.4);
  transform: translateY(-2px);
}

/* Responsive */
@media (max-width: 768px) {
  header h1 {
    font-size: 1.8rem;
  }

  main {
    flex-direction: column;
    align-items: center;
  }

  .controls-panel {
    width: 100%;
    max-width: 400px;
  }

  #packingCanvas {
    width: 100%;
    height: auto;
  }
}