@import url('https://fonts.googleapis.com/css?family=Roboto:400,500&display=swap');

/* Base styling */
body {
  margin: 0;
  background-color: #f7f8fa;
  font-family: 'Roboto', sans-serif;
  color: #333;
}

/* Layout containers */
#main-container {
  display: flex;
  width: 90%;
  max-width: 1200px;
  margin: 30px auto;
  gap: 20px;
}

#tree-container,
#stack-container {
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
  padding: 16px;
}

#tree-container {
  flex: 3;
  height: 600px;
}

#stack-container {
  flex: 1;
  height: 600px;
  box-sizing: border-box;
}

/* Stack title */
#stack-title {
  font-size: 20px;
  text-align: center;
  margin-bottom: 12px;
  color: #555;
}

/* Controls */
#tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 20px;
}

.tab-btn {
  background: transparent;
  color: #555;
  padding: 8px 16px;
  font-size: 16px;
  border: none;
  border-bottom: 3px solid transparent;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
}

.tab-btn:hover {
  color: #007bff;
}

.tab-btn.active,
.tab-btn[style*="font-weight: bold"] {
  color: #007bff;
  border-color: #007bff;
}

#controls {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin: 20px 0;
}

button {
  padding: 12px 24px;
  font-size: 16px;
  background-color: #007bff;
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.1s ease;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
}

button:hover {
  background-color: #006ae6;
}

button:active {
  transform: translateY(1px);
}

/* Status & logs */
#status,
#log,
#final-seq {
  width: 90%;
  max-width: 1200px;
  margin: 10px auto;
  padding: 16px;
  background-color: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

#status {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 18px;
}

#log {
  height: 120px;
  overflow-y: auto;
}

.label {
  font-weight: 500;
  color: #666;
}

#currentVal {
  color: #007bff;
  font-weight: 500;
}

#reason {
  color: #ff5722;
  font-weight: 500;
}

#final-seq {
  font-weight: 500;
  color: #28a745;
}