<div class="container">
  <form>
    <h3>登录</h3>
    <div class="inputBox">
      <span>用户名</span>
      <div class="box">
        <div class="icon"><ion-icon name="person"></ion-icon></div>
        <input type="text">
      </div>
    </div>
    <div class="inputBox">
      <span>密码</span>
      <div class="box">
        <div class="icon"><ion-icon name="lock-closed"></ion-icon></div>
        <input type="password">
      </div>
    </div>
    <label>
      <input type="checkbox"> 记住我
    </label>
    <div class="inputBox">
      <div class="box">
        <input type="submit" value="登录">
      </div>
    </div>
    <a href="#" class="forgot">忘记密码</a>
  </form>
</div>
<script type="module" src="https://unpkg.com/ionicons@5.5.2/dist/ionicons/ionicons.esm.js"></script>
  <script nomodule src="https://unpkg.com/ionicons@5.5.2/dist/ionicons/ionicons.js"></script>

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #2f363e;
}

.container {
  position: relative;
  width: 350px;
  min-height: 500px;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #2f363e;
  box-shadow: 25px 25px 75px rgba(0,0,0,0.25),
  10px 10px 70px rgba(0,0,0,0.25),
  inset 5px 5px 10px rgba(0,0,0,0.5),
  inset 5px 5px 20px rgba(255,255,255,0.2),
  inset -5px -5px 15px rgba(0,0,0,0.75);
  border-radius: 30px;
  padding: 50px;
}

form {
  position: relative;
  width: 100%;
}

.container h3 {
  color: #fff;
  font-weight: 600;
  font-size: 2em;
  width: 100%;
  text-align: center;
  margin-bottom: 30px;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.inputBox {
  position: relative;
  width: 100%;
  margin-bottom: 20px;
}

.inputBox span {
  display: inline-block;
  color: #fff;
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-size: 0.75em;
  border-left: 4px solid #fff;
  padding-left: 4px;
  line-height: 1em;
}

.inputBox .box {
  display: flex;
}

.inputBox .box .icon {
  position: relative;
  min-width: 40px;
  height: 40px;
  background: #00a6bc;
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: 50%;
  margin-right: 10px;
  color: #fff;
  font-size: 1.15em;
  box-shadow: 5px 5px 7px rgba(0,0,0,0.25),
  inset 2px 2px 5px rgba(255,255,255,0.25),
  inset -3px -3px 5px rgba(0,0,0,0.5);
}

.inputBox .box input {
  position: relative;
  width: 100%;
  border: none;
  outline: none;
  padding: 10px 20px;
  border-radius: 30px;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-size: 0.85em;
  box-shadow: 5px 5px 7px rgba(0,0,0,0.25),
  inset 2px 2px 5px rgba(0,0,0,0.35),
  inset -3px -3px 5px rgba(0,0,0,0.5);
}

.inputBox .box input[type="submit"] {
  background: #1f83f2;
  box-shadow: 5px 5px 7px rgba(0,0,0,0.25),
  inset 2px 2px 5px rgba(255,255,255,0.25),
  inset -3px -3px 5px rgba(0,0,0,0.5);
  color: #fff;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 2px;
  font-weight: 600;
  margin-top: 10px;
}

.inputBox .box input[type="submit"]:hover {
  filter: brightness(1.1);
}

label {
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-size: 0.85em;
  display: flex;
  align-items: center;
}

label input {
  margin-right: 5px;
}

.forgot {
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-size: 0.85em;
  text-decoration: none;
}