.km-to-mph-tool {
      font-family: 'Poppins', sans-serif;
      margin: 40px auto;
      max-width: 800px;
      padding: 40px;
      border-radius: 25px;
      background: linear-gradient(135deg, #d77421, #912f38);
      box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
      color: #fff;
      text-align: center;
      overflow: hidden;
      position: relative;
      transition: transform 0.3s ease;
    }

    .km-to-mph-tool:hover {
      transform: translateY(-5px);
    }

    .tool-title {
      font-size: 2.5rem;
      font-weight: bold;
      letter-spacing: 1px;
      margin-bottom: 30px;
      text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.4);
    }

    .swap-container {
      margin-bottom: 20px;
    }

    .swap-btn {
      padding: 10px 20px;
      font-size: 1.1rem;
      font-weight: 600;
      color: #fff;
      background: linear-gradient(135deg, #6dd5ed, #2193b0);
      border: none;
      border-radius: 15px;
      cursor: pointer;
      transition: transform 0.3s ease, background 0.3s ease;
    }

    .swap-btn:hover {
      transform: scale(1.05);
      background: linear-gradient(135deg, #2193b0, #6dd5ed);
    }

    .input-group {
      margin-bottom: 25px;
    }

    .input-group label {
      display: block;
      font-size: 1.2rem;
      font-weight: 500;
      margin-bottom: 10px;
      letter-spacing: 0.5px;
      text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.3);
    }

    .input-group input {
      width: 100%;
      padding: 15px;
      font-size: 1.1rem;
      font-weight: 500;
      border: none;
      border-radius: 15px;
      outline: none;
      background: rgba(255, 255, 255, 0.1);
      color: #fff;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }

    .input-group input:focus {
      transform: scale(1.02);
      box-shadow: 0 6px 10px rgba(0, 0, 0, 0.3);
    }

    .button-group {
      display: flex;
      justify-content: space-between;
      gap: 15px;
      margin-bottom: 25px;
    }

    .btn {
      flex: 1;
      padding: 15px;
      font-size: 1.1rem;
      font-weight: 600;
      color: #fff;
      background: linear-gradient(135deg, #6dd5ed, #2193b0);
      border: none;
      border-radius: 15px;
      cursor: pointer;
      transition: transform 0.3s ease, background 0.3s ease;
    }

    .btn:hover {
      transform: scale(1.05);
      background: linear-gradient(135deg, #2193b0, #6dd5ed);
    }

    .result {
      margin-top: 20px;
    }

    .result-text {
      font-size: 1.7rem;
      font-weight: bold;
      letter-spacing: 1px;
      text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.3);
    }

    .result-text span {
      color: #ffeb3b;
      text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.4);
    }

    .history {
      margin-top: 30px;
    }

    .history-title {
      font-size: 1.6rem;
      font-weight: bold;
      margin-bottom: 15px;
      text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.3);
    }

    .history-list {
      list-style: none;
      padding: 0;
      max-height: 180px;
      overflow-y: auto;
      border: 1px solid rgba(255, 255, 255, 0.5);
      border-radius: 15px;
      background: rgba(255, 255, 255, 0.1);
    }

    .history-list li {
      padding: 12px;
      font-size: 1.1rem;
      border-bottom: 1px solid rgba(255, 255, 255, 0.3);
      transition: background 0.3s ease;
    }

    .history-list li:last-child {
      border-bottom: none;
    }

    .history-list li:hover {
      background: rgba(255, 255, 255, 0.2);
    }