body {
          background: linear-gradient(120deg, #f8ffae 0%, #43c6ac 100%);
          font-family: 'Segoe UI', Arial, sans-serif;
          min-height: 100vh;
          margin: 0;
          display: flex;
          flex-direction: column;
          align-items: center;
          justify-content: flex-start;
      }
      nav {
          width: 100%;
          background: rgba(255,255,255,0.85);
          box-shadow: 0 2px 8px rgba(67,198,172,0.10);
          padding: 16px 0;
          display: flex;
          justify-content: center;
          gap: 32px;
          margin-bottom: 32px;
      }
      nav a {
          color: #2d3a3a;
          text-decoration: none;
          font-size: 1.1rem;
          font-weight: 500;
          padding: 8px 18px;
          border-radius: 8px;
          transition: background 0.2s, color 0.2s;
      }
      nav a:hover {
          background: #e0f7fa;
          color: #43c6ac;
      }
      .container {
          background: rgba(255,255,255,0.97);
          border-radius: 18px;
          box-shadow: 0 2px 16px rgba(67,198,172,0.10);
          padding: 40px 32px 32px 32px;
          max-width: 370px;
          width: 100%;
          text-align: center;
      }
      h1 {
          color: #2d3a3a;
          margin-bottom: 24px;
          letter-spacing: 1px;
      }
      label {
          color: #43c6ac;
          font-weight: 500;
      }
      input[type="text"] {
          width: 80%;
          padding: 10px;
          border-radius: 8px;
          border: 1px solid #43c6ac;
          font-size: 1rem;
          margin-bottom: 10px;
          outline: none;
          transition: border 0.2s;
      }
      input[type="text"]:focus {
          border: 2px solid #2d3a3a;
      }
      button {
          background: #43c6ac;
          color: #fff;
          border: none;
          border-radius: 8px;
          padding: 12px 32px;
          font-size: 1.1rem;
          font-weight: 500;
          cursor: pointer;
          margin-top: 18px;
          transition: background 0.2s;
      }
      button:hover {
          background: #2d3a3a;
      }
      #results, #advice {
          margin-top: 24px;
          font-size: 1.2rem;
          color: #2d3a3a;
          background: #e0f7fa;
          border-radius: 8px;
          padding: 12px;
          box-shadow: 0 2px 8px rgba(67,198,172,0.08);
      }
      #weight-guide {
          background: #f8ffae;
          border-radius: 10px;
          padding: 16px;
          margin-top: 24px;
          box-shadow: 0 2px 8px rgba(67,198,172,0.08);
      }
      #weight-guide h3 {
          color: #43c6ac;
          margin-bottom: 10px;
      }
      #weight-guide p {
          color: #2d3a3a;
          margin: 6px 0;
      }