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

:root {
  --font-size: 16px;
  --radius: 0.625rem;

  /* Color Variables */
  --coral-50: #fef7f0;
  --coral-100: #feecdc;
  --coral-200: #fcd9bd;
  --coral-300: #fdba8c;
  --coral-400: #ff8a4c;
  --coral-500: #ff5722;
  --coral-600: #e53e3e;

  --violet-300: #c4b5fd;
  --violet-400: #a78bfa;
  --amber-300: #fcd34d;
  --amber-400: #f59e0b;
  --rose-300: #fda4af;
  --rose-400: #fb7185;
  --orange-300: #fdba74;
  --orange-400: #fb923c;
  --cyan-300: #67e8f9;
  --cyan-400: #22d3ee;
  --cyan-600: #0891b2;
  --emerald-300: #6ee7b7;
  --emerald-400: #34d399;

  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-600: #4b5563;
  --gray-700: #374151;

  --white: #ffffff;
  --black: #000000;
}

html {
  font-size: var(--font-size);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.5;
  color: var(--gray-700);
}

.app {
  min-height: 100vh;
  background: linear-gradient(to bottom right, #fdf2f8, #faf5ff, #eef2ff);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.header {
  background: linear-gradient(to right, var(--coral-500), #fb7185, #ec4899);
  color: white;
  padding: 1.5rem 0;
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.sparkles-icon {
  width: 2rem;
  height: 2rem;
}

.logo h1 {
  font-size: 2.25rem;
  font-weight: bold;
}

.algorithm-display {
  font-size: 1.125rem;
  font-weight: 500;
}

.main {
  padding: 2rem 0;
}

/* Controls Card */
.controls-card {
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.controls-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  align-items: end;
}

.control-group {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

#sizeError {
  position: absolute;
  top: 0;
  right: 0;
  color: #ff5722;
}

.control-group label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--gray-700);
}

/* Form Elements */
.select-wrapper {
  position: relative;
}

.select,
.input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--gray-200);
  border-radius: calc(var(--radius) - 2px);
  font-size: 0.875rem;
  transition: all 0.2s ease;
  outline: none;
}

.select {
  background: linear-gradient(to right, #faf5ff, #fdf2f8);
  border-color: #d8b4fe;

  appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
  background-position: right 0.5rem center;
  background-repeat: no-repeat;
  background-size: 1.5em 1.5em;
  padding-right: 2.5rem;
}

/* Style dropdown options */
.select option {
  padding: 10px;
  font-size: 14px;
}

/* Highlight selected option */
.select option:checked {
  background-color: #f3e8ff; /* light purple background */
  color: #000;
}

/* Highlight on hover */
.select option:hover {
  background-color: #f5fff7; /* very light purple */
}

.input:nth-of-type(1) {
  background: linear-gradient(to right, #eff6ff, #ecfeff);
}

#speed {
  background: linear-gradient(to right, #f0fdf4, #ecfdf5);
}

.select:focus,
.input:focus {
  border-color: var(--coral-400);
  box-shadow: 0 0 0 3px rgba(255, 87, 34, 0.1);
}

/* Buttons */
.button-group {
  display: flex;
  gap: 0.5rem;
}

.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1rem;
  border: none;
  border-radius: calc(var(--radius) - 2px);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
  outline: none;
}

.btn svg {
  width: 1rem;
  height: 1rem;
}

.btn-primary {
  background: linear-gradient(to right, var(--coral-500), #fb7185);
  color: white;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  flex: 1;
}

.btn-primary:hover {
  background: linear-gradient(to right, var(--coral-600), #e11d48);
  transform: translateY(-1px);
  box-shadow: 0 6px 12px -2px rgba(0, 0, 0, 0.15);
}

.btn-secondary {
  background: linear-gradient(to right, var(--gray-50), var(--gray-100));
  color: var(--gray-700);
  border: 1px solid var(--gray-200);
}

.btn-secondary:hover {
  background: linear-gradient(to right, var(--gray-100), var(--gray-200));
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.hidden {
  display: none;
}

/* Visualization Card */
.visualization-card {
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.visualization-container {
  position: relative;
  height: 24rem;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: visible;
  transition: all 0.5s ease;
}

.bars-container {
  display: flex;
  align-items: end;
  justify-content: center;
  gap: 2px;
  height: 12rem;
  position: relative;
}

/* Individual Bars */
.bar {
  min-width: 18px;
  flex: 1;
  max-width: 40px;
  border-radius: 4px 4px 0 0;
  position: relative;
  transition: all 0.5s ease-in-out;

  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  z-index: 10;

  background-color: var(--violet-400);

  display: flex;
  justify-content: center;
  align-items: flex-end;

  font-size: 0.75rem;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.9);

  transform: translateX(0) translateY(0);
}

.bar.first-render {
  animation: growUp 0.5s ease forwards;
}

@keyframes growUp {
  from {
    height: 0;
  }
  to {
    height: var(--target-height);
  }
}

/* Legend */
.legend {
  margin-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.legend-color {
  width: 1rem;
  height: 1rem;
  border-radius: 2px;
}

.legend-color.unsorted {
  background: linear-gradient(to top, var(--violet-400), var(--violet-300));
}

.legend-color.comparing {
  background-color: #fcd34d;
}

.legend-color.swapping {
  background: linear-gradient(to top, var(--rose-400), var(--rose-300));
}

.legend-color.shifting {
  background: linear-gradient(to top, var(--orange-400), var(--orange-300));
}

.legend-color.subarray {
  background: linear-gradient(to top, var(--cyan-400), var(--cyan-300));
}

.legend-color.sorted {
  background: linear-gradient(to top, var(--emerald-400), var(--emerald-300));
}

.legend-item span {
  font-size: 0.875rem;
  color: var(--gray-600);
}

/* Footer */
.footer {
  background: linear-gradient(to right, #6366f1, #8b5cf6, #ec4899);
  color: white;
  padding: 1rem 0;
  margin-top: 3rem;
  text-align: center;
}

.footer p {
  font-size: 0.875rem;
  opacity: 0.9;
}

/* Responsive Design */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .logo h1 {
    font-size: 1.875rem;
  }

  .controls-grid {
    grid-template-columns: 1fr;
  }

  .button-group {
    justify-content: center;
  }

  .legend {
    gap: 0.5rem;
  }

  .legend-item span {
    font-size: 0.75rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 1rem;
  }

  .visualization-card {
    padding: 1rem;
  }
}