.form-container {
    position: relative;
    width: 350px;
    height: 340px;
    border-radius: 15px;
    border: #45f3ff;
    border-width: 1px;
    box-shadow: 0 5px 25px rgba(0, 0, 0, 0.25); 
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000; 
    transition: 0.5s;
    overflow: hidden;
    /* 磨砂玻璃效果，对后面的元素进行模糊处理 
    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);
    */
}

/* 表单背景，用于遮挡流光效果 */
.form-background {
    position: absolute;
    inset: 3px;
    overflow: hidden;
    border-radius: 15px;
    display: flex;
    justify-content: center;
    align-items: center;

    background-size: auto;
    background-repeat: no-repeat;
    background-position: center;
}

/* 用于承载表单实际内容 */
.form-box {
    position: absolute;
    inset: 0;
    overflow: hidden;
    border-radius: 15px;
    display: flex;
    justify-content: center;
    align-items: center;
    backdrop-filter: blur(3px);
    /* webkit 无效测试 */
    -webkit-backdrop-filter: blur(3px);
    /*isolation: isolate;
    z-index: 0; */
}

.form-container::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: repeating-conic-gradient(from var(--a), #45f3ff 0%, #45f3ff 10%, transparent 10%, transparent 80%, #45f3ff 100%);
    border-radius: 20px;
    animation: animate 2.5s linear infinite;
}
  
@property --a {
    syntax: '<angle>';
    inherits: false;
    initial-value: 0deg;
}

@keyframes animate {
    0% {
        --a: 0deg;
    }
    100% {
        --a: 360deg;
    }
}
  
.login-form {
    position: absolute;
    left: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    width: 100%;
    gap: 15px;
    transition: 0.5s;
}

.login-form h2 {
    position: relative;
    color: #FFF;
    font-size: 1.5em;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    font-weight: 500;
    margin-bottom: 10px;
}

.login-form .input-box {
    position: relative;
    width: 70%;
    display: flex;
    justify-content: space-between;
}

.login-form .input-box a {
    color: #fff;
    text-decoration: none;
    font-size: 0.85em;
}

.login-form .input-box a:nth-child(2) {
    text-decoration: underline;
}

.login-form .input-box input {
    width: 100%;
    outline: none;
    border: 1px solid rgba(255,255,255,0.25);
    background: rgba(0,0,0,0.15);
    padding: 6px 15px;
    border-radius: 4px;
    font-size: 0.85em;
    color: #fff;
    /* 测试高度 */
    height: auto; /* 自动计算高度，配合min-height和max-height使用 */
    min-height: 2rem; /* 设置最小高度 */
    max-height: 6rem; /* 设置最大高度 */
    box-sizing: border-box; /* 必须，使边框和内边距计入元素总高度 */
}


/* 自适应布局，媒体查询当宽度大于528像素时 */
@media (max-width: 768px) {
    .form-container {
        width: 90%;
        height: 400px;
    }

    .login-form h2 {
        font-size: 2.5em;
    }

    .login-form .input-box {
        width: 90%;
    }

    .login-form .input-box input {
        font-size: 1.4em;
    }

    .login-form .input-box a {
        font-size: 1.4em;
    }
}