:root {
    --primary: #64748b;
    --primary-hover: #475569;
    --background: #f8fafc;
    --text: #1e293b;
    --card: #ffffff;
    --shadow: rgba(0, 0, 0, 0.1);
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  }
  
  body {
    background-color: var(--background);
    color: var(--text);
    min-height: 100vh;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
  }
  
  h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    text-align: center;
  }
  
  h2 {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 1.5rem;
    opacity: 0.7;
    text-align: center;
  }
  
  .container {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
  }
  
  .controls {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    background-color: var(--card);
    padding: 1.5rem;
    box-shadow: 0 4px 6px var(--shadow);
    margin-bottom: 2rem;
  }
  
  .control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
  }
  
  label {
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }
  
  input[type="color"] {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    width: 3rem;
    height: 3rem;
    border: none;
    background: none;
    cursor: pointer;
  }
  
  input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 0;
  }
  
  input[type="color"]::-webkit-color-swatch {
    border: none;
    box-shadow: 0 2px 4px var(--shadow);
  }
  
  input[type="color"]::-moz-color-swatch {
    border: none;
    box-shadow: 0 2px 4px var(--shadow);
  }
  
  select {
    padding: 0.5rem;
    border: 1px solid #ccc;
    background-color: white;
    font-size: 1rem;
    min-width: 200px;
  }
  
  .harmony-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 0.5rem;
    width: 100%;
  }
  
  .harmony-options button {
    background-color: var(--background);
    border: 1px solid #ccc;
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.9rem;
    text-align: center;
    height: 100%;
    min-height: 40px;
  }
  
  .harmony-options button.active {
    background-color: var(--primary);
    color: white;
    border-color: var(--primary);
  }
  
  .harmony-options button.active:hover {
    background-color: var(--primary-hover);
  }
  
  .harmony-options button:hover:not(.active) {
    background-color: #e2e8f0;
  }
  
  .palette {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
  }
  
  .colour-card {
    background-color: var(--card);
    overflow: hidden;
    box-shadow: 0 4px 6px var(--shadow);
    transition: transform 0.3s;
    position: relative;
  }
  
  .colour-card:hover {
    transform: translateY(-5px);
  }
  
  .colour-preview {
    height: 120px;
    width: 100%;
  }
  
  .colour-info {
    padding: 1rem;
  }
  
  .colour-hex {
    font-family: monospace;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .copy-btn {
    background: none;
    border: none;
    cursor: pointer;
    opacity: 0.6;
    transition: opacity 0.2s;
  }
  
  .copy-btn:hover {
    opacity: 1;
  }
  
  .copy-btn svg {
    width: 16px;
    height: 16px;
  }
  
  .colour-rgb, .colour-hsl {
    font-size: 0.85rem;
    opacity: 0.7;
    margin-bottom: 0.25rem;
  }
  
  .alert {
    position: fixed;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary);
    color: white;
    padding: 0.75rem 1.5rem;
    box-shadow: 0 4px 6px var(--shadow);
    opacity: 0;
    transition: opacity 0.3s;
    pointer-events: none;
  }
  
  .alert.show {
    opacity: 1;
  }
  
  @media (min-width: 768px) {
    .controls {
      flex-direction: column;
      align-items: flex-start;
      gap: 1.5rem;
    }
  
    .control-group:first-child {
      align-self: center;
      margin-bottom: 0.5rem;
    }
  }
  
  @media (max-width: 480px) {
    .palette {
      grid-template-columns: repeat(2, 1fr);
    }
  }