:root {
    --primary-color: rgb(22 163 74);
    --primary-light: rgb(220 252 231);
    --gray-100: rgb(243 244 246);
    --gray-200: rgb(229 231 235);
    --gray-700: rgb(55 65 81);
    --gray-800: rgb(31 41 55);
    --blue-50: rgb(239 246 255);
    --blue-700: rgb(29 78 216);
    --blue-800: rgb(30 64 175);
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: system-ui, -apple-system, sans-serif;
    background: linear-gradient(to bottom right, var(--primary-light), rgb(236 253 245));
    min-height: 100vh;
    color: var(--gray-800);
  }
  
  .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
  }
  
  .header {
    text-align: center;
    margin-bottom: 2.5rem;
  }
  
  .header h1 {
    font-size: 2.5rem;
    color: rgb(22 101 52);
    margin-bottom: 0.5rem;
  }
  
  .header p {
    color: var(--gray-700);
  }
  
  .grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  @media (min-width: 768px) {
    .grid {
      grid-template-columns: 1fr 1fr;
    }
  }
  
  .input-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
  }
  
  .card {
    background: white;
    border-radius: 0.75rem;
    padding: 1.5rem;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  }
  
  .card h2 {
    font-size: 1.5rem;
    color: var(--gray-800);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }
  
  .input-group {
    margin-bottom: 1rem;
  }
  
  .input-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--gray-700);
    margin-bottom: 0.25rem;
  }
  
  .input-group input,
  .input-group select {
    width: 100%;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--gray-200);
    border-radius: 0.375rem;
    font-size: 1rem;
    background-color: white;
  }
  
  .input-group input:focus,
  .input-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(22, 163, 74, 0.1);
  }
  
  .input-group input[readonly] {
    background-color: var(--gray-100);
    cursor: not-allowed;
  }
  
  .device-item {
    background: var(--gray-100);
    border-radius: 0.5rem;
    padding: 1rem;
    margin-bottom: 1rem;
    position: relative;
  }
  
  .device-item .remove-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: none;
    border: none;
    color: rgb(239 68 68);
    cursor: pointer;
    padding: 0.25rem;
  }
  
  .device-item .remove-btn:hover {
    color: rgb(185 28 28);
  }
  
  .device-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
  }
  
  .add-device-btn {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background: rgb(220 252 231);
    color: var(--primary-color);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
  }
  
  .add-device-btn:hover {
    background: rgb(187 247 208);
  }
  
  .calculate-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1rem;
    border-radius: 0.375rem;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
  }
  
  .calculate-btn:hover {
    background: rgb(21 128 61);
  }
  
  .results-section {
    position: sticky;
    top: 2rem;
  }
  
  .result-card {
    background: var(--gray-100);
    border-radius: 0.5rem;
    padding: 1rem;
    margin-bottom: 1rem;
  }
  
  .result-card h3 {
    font-size: 1.125rem;
    color: var(--gray-700);
    margin-bottom: 0.5rem;
  }
  
  .result-value {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--primary-color);
  }
  
  .result-desc {
    font-size: 0.875rem;
    color: var(--gray-700);
    margin-top: 0.25rem;
  }
  
  .total-result {
    background: rgb(220 252 231);
    border-radius: 0.5rem;
    padding: 1rem;
  }
  
  .total-result h3 {
    font-size: 1.25rem;
    color: rgb(22 101 52);
    margin-bottom: 0.5rem;
  }
  
  .tips-card {
    background: var(--blue-50);
    border-radius: 0.75rem;
    padding: 1rem;
    margin-top: 1.5rem;
  }
  
  .tips-card h3 {
    font-size: 1.125rem;
    color: var(--blue-800);
    margin-bottom: 0.5rem;
  }
  
  .tips-card ul {
    list-style: none;
  }
  
  .tips-card li {
    color: var(--blue-700);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
    padding-left: 1rem;
    position: relative;
  }
  
  .tips-card li::before {
    content: "•";
    position: absolute;
    left: 0;
  }