has/index.html

<!DOCTYPE html>
<html lang="ru">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="preconnect" href="https://fonts.googleapis.com">
  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
  <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Roboto&display=swap">
  <title>Демо для has()</title>
  <style>
    *,
    *::before,
    *::after {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      min-height: 100vh;
      padding: 50px;
      display: flex;
      align-items: center;
      justify-content: center;
      background-color: #18191C;
      color: #FFFFFF;
      font-family: "Roboto", sans-serif;
      font-size: 18px;
    }

    @media (max-width: 768px) {
      body {
        padding: 30px;
      }
    }

    .container {
      display: flex;
      align-items: start;
      gap: 50px;
    }

    .form {
      position: relative;
      display: grid;
      padding: 25px;
      gap: 25px;
      width: 450px;
      background-color: #282A2E;
      color: #E6E6E6;
    }

    .form:has(input[type='text']) {
      background-image: linear-gradient(rgb(161 0 255/ 0.3), rgb(112 196 255/ 0.5));
    }

    input {
      width: 100%;
      border: 1px solid #FFFFFF;
      border-radius: 6px;
      padding: 10px 15px;
      background-color: transparent;
      color: #FFFFFF;
      font-size: 18px;
      font-weight: 300;
      font-family: inherit;
      -webkit-appearance: none;
      appearance: none;
    }

    input:focus {
      border-color: #2E9AFF;
      outline: none;
    }

    button {
      display: block;
      min-width: 210px;
      border: 2px solid transparent;
      border-radius: 6px;
      padding: 9px 15px;
      color: #000000;
      font-size: 18px;
      font-weight: 300;
      font-family: inherit;
      transition: background-color 0.2s linear;
      background-color: #2E9AFF;
    }

    button:hover {
      background-color: #FFFFFF;
      cursor: pointer;
      transition: background-color 0.2s linear;
    }

    button:focus-visible {
      border: 2px solid #FFFFFF;
      outline: none;
    }

    button:focus {
      border: 2px solid #FFFFFF;
      outline: none;
    }
  </style>
</head>
<body>
  <div class="container">
    <form class="form">
      <label for="email">Введите ваш емейл</label>
      <input type="email">
      <button>Подписаться</button>
    </form>
    <form class="form">
      <label for="name">Введите ваше имя</label>
      <input type="text">
      <label for="email">Введите ваш емейл</label>
      <input type="email">
      <button>Зарегистрироваться</button>
    </form>
  </div>
</body>
</html>