:root {
      --lapis: #355E8C;
      --celadon: #B8D1AD;
      --dark-celadon: #9cb593;
      --lapis-light: #4a7aac;
      --lapis-dark: #2c4f77;
      --text-dark: #333;
      --text-light: #fff;
      --border-light: #d5e1d1;
    }

    body {
      background: linear-gradient(135deg, #f0f7ee 0%, #e6f0e3 100%);
      color: var(--text-dark);
      min-height: 100vh;
      margin: 0;
      font-family: 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', sans-serif;
      background-attachment: fixed;
    }

    .sidebar {
      height: 100vh;
      position: fixed;
      width: 250px;
      top: 0;
      left: 0;
      background: linear-gradient(135deg, var(--lapis) 0%, var(--lapis-dark) 100%);
      padding: 1.5rem 1rem;
      border-right: 1px solid var(--lapis-dark);
      box-shadow: 0 0 20px rgba(53, 94, 140, 0.4);
      z-index: 1000;
      overflow-y: auto;
    }

    .sidebar h5 {
      font-weight: bold;
      color: var(--text-light);
      letter-spacing: 0.5px;
    }

    .sidebar .logo-container {
      /* background-color: var(--celadon); */
      padding: 0.8rem;
      /* border-radius: 12px; */
      margin-bottom: 1.5rem;
      /* box-shadow: 0 4px 15px rgba(184, 209, 173, 0.4); */
      transition: transform 0.3s ease;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .sidebar .logo-container:hover {
      transform: translateY(-3px);
    }

    .logo-container .logo-m {
      font-size: 2.2rem;
      font-weight: 900;
      color: var(--lapis);
      text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    }

    .sidebar .nav-link {
      margin-bottom: 0.5rem;
      padding: 0.8rem 1rem;
      border-radius: 8px;
      color: var(--text-light);
      transition: all 0.3s ease;
      font-weight: 500;
      background-color: rgba(255, 255, 255, 0.1);
    }

    .sidebar .nav-link:hover {
      background-color: rgba(255, 255, 255, 0.25);
      transform: translateX(5px);
    }

    .sidebar .nav-link.active {
      background-color: var(--celadon);
      color: var(--lapis) !important;
      font-weight: 600;
      box-shadow: 0 4px 12px rgba(184, 209, 173, 0.4);
    }

    .sidebar .nav-link i {
      width: 24px;
      text-align: center;
      font-size: 1.1rem;
      margin-right: 12px;
      color: var(--celadon);
      transition: transform 0.3s ease;
    }

    .sidebar .nav-link.active i {
      color: var(--lapis);
    }

    .sidebar .nav-link:hover i {
      transform: scale(1.2);
    }

    .content {
      margin-left: 270px;
      padding: 2.5rem;
      padding-top: 1.5rem;
    }

    .converter-card {
      background-color: white;
      border-radius: 16px;
      padding: 2.5rem;
      box-shadow: 0 10px 30px rgba(184, 209, 173, 0.4);
      border: 1px solid var(--border-light);
      max-width: 800px;
      margin: 2rem auto 0;
    }

    .converter-title {
      color: var(--lapis);
      font-weight: 700;
      font-size: 2.2rem;
      margin-bottom: 1.5rem;
      text-align: center;
      position: relative;
      padding-bottom: 15px;
    }

    .converter-title::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 80px;
      height: 4px;
      background: linear-gradient(90deg, var(--lapis), var(--lapis-dark));
      border-radius: 2px;
    }

    .input-label {
      color: var(--lapis);
      font-weight: 500;
      margin-bottom: 0.8rem;
      display: block;
      text-align: center;
    }

    .input-value {
      background-color: white;
      border: 2px solid var(--celadon);
      color: var(--lapis);
      font-size: 1.2rem;
      padding: 0.8rem 1.2rem;
      border-radius: 12px;
      text-align: center;
      width: 100%;
      max-width: 300px;
      margin: 0 auto;
      display: block;
      transition: all 0.3s ease;
      box-shadow: inset 0 2px 5px rgba(184, 209, 173, 0.3);
    }

    .input-value:focus {
      border-color: var(--lapis);
      box-shadow: 0 0 0 0.25rem rgba(53, 94, 140, 0.25);
      outline: none;
    }

    .units-container {
      display: flex;
      justify-content: center;
      gap: 2rem;
      margin-top: 2.5rem;
      flex-wrap: wrap;
    }

    .unit-selector {
      flex: 1;
      min-width: 250px;
    }

    .unit-selector label {
      color: var(--lapis);
      font-weight: 500;
      margin-bottom: 0.8rem;
      display: block;
      text-align: center;
    }

    .form-select {
      background-color: white;
      border: 2px solid var(--celadon);
      color: var(--lapis);
      padding: 0.8rem 1.2rem;
      border-radius: 12px;
      width: 100%;
      transition: all 0.3s ease;
      box-shadow: inset 0 2px 5px rgba(184, 209, 173, 0.3);
    }

    .form-select:focus {
      border-color: var(--lapis);
      box-shadow: 0 0 0 0.25rem rgba(53, 94, 140, 0.25);
    }

    .btn-convert {
      background: linear-gradient(135deg, var(--lapis) 0%, var(--lapis-dark) 100%);
      color: white !important;
      border: none;
      padding: 0.9rem 2rem;
      font-size: 1.1rem;
      font-weight: 600;
      border-radius: 12px;
      display: block;
      margin: 3rem auto 0;
      width: 100%;
      max-width: 300px;
      transition: all 0.3s ease;
      box-shadow: 0 6px 15px rgba(53, 94, 140, 0.4);
      position: relative;
      overflow: hidden;
    }

    .btn-convert:hover {
      transform: translateY(-3px);
      box-shadow: 0 10px 25px rgba(53, 94, 140, 0.6);
      background: linear-gradient(135deg, var(--lapis-light) 0%, var(--lapis) 100%);
    }

    .btn-convert:active {
      transform: translateY(1px);
    }

    #resultArea {
      background: rgba(184, 209, 173, 0.3);
      border: 2px solid var(--celadon);
      border-radius: 12px;
      padding: 1.5rem;
      margin-top: 2.5rem;
      text-align: center;
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--lapis);
      transition: all 0.4s ease;
      min-height: 100px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    #introMessage {
      background: white;
      border-radius: 16px;
      padding: 3rem 2rem;
      text-align: center;
      margin-top: 3rem;
      box-shadow: 0 10px 30px rgba(184, 209, 173, 0.4);
      border: 1px solid var(--border-light);
      color: var(--lapis);
      font-size: 1.3rem;
    }

    #introMessage i {
      font-size: 3rem;
      display: block;
      margin-bottom: 1.5rem;
      color: var(--lapis);
    }

    .watermark {
      position: fixed;
      bottom: 20px;
      right: 20px;
      width: 120px;
      opacity: 0.15;
      z-index: -1;
    }

    .fade-in {
      animation: fadeIn 0.6s ease-in-out;
    }

    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(20px); }
      to { opacity: 1; transform: translateY(0); }
    }

    .pulse {
      animation: pulse 2s infinite;
    }

    @keyframes pulse {
      0% { box-shadow: 0 0 0 0 rgba(53, 94, 140, 0.5); }
      70% { box-shadow: 0 0 0 15px rgba(53, 94, 140, 0); }
      100% { box-shadow: 0 0 0 0 rgba(53, 94, 140, 0); }
    }

    @media (max-width: 992px) {
      .sidebar {
        width: 70px;
        padding: 1rem 0.5rem;
      }
      .sidebar .logo-text, .sidebar .nav-link span {
        display: none;
      }
      .sidebar .logo-container {
        padding: 0.5rem;
        text-align: center;
      }
      .sidebar .nav-link {
        text-align: center;
        padding: 0.8rem 0.5rem;
      }
      .sidebar .nav-link i {
        margin-right: 0;
        font-size: 1.4rem;
      }
      .content {
        margin-left: 90px;
        padding: 1.5rem;
      }
    }

    @media (max-width: 576px) {
      .units-container {
        flex-direction: column;
        gap: 1.5rem;
      }
      .converter-card {
        padding: 1.5rem;
      }
    }