/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* 背景效果 - 黑色+深蓝色渐变，动态循环 */
body {
    min-height: 100vh;
    background: linear-gradient(135deg, #000000 0%, #0a192f 50%, #112240 100%);
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

/* 背景渐变动画 */
@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* 登录容器 */
.login-container {
    position: relative;
    width: 100%;
    max-width: 400px;
}

/* 登录框样式 - 深色玻璃态 */
.login-box {
    background: rgba(10, 25, 47, 0.6);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 8px 32px 0 rgba(0, 15, 30, 0.3);
    border: 1px solid rgba(136, 165, 191, 0.18);
    position: relative;
    overflow: hidden;
}

/* 装饰元素 - 科技蓝流动光效 */
.login-box::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 400px;
    height: 400px;
    background: linear-gradient(0deg, transparent, #64ffda, #64ffda);
    transform-origin: bottom right;
    animation: animate 6s linear infinite;
}

.login-box::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 400px;
    height: 400px;
    background: linear-gradient(0deg, transparent, #64ffda, #64ffda);
    transform-origin: bottom right;
    animation: animate 6s linear infinite;
    animation-delay: -3s;
}

@keyframes animate {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 登录框内容（覆盖装饰元素） */
.login-box > * {
    position: relative;
    z-index: 1;
}

/* 标题样式 - 浅灰蓝文字，带阴影 */
.login-box h2 {
    color: #ccd6f6;
    text-align: center;
    margin-bottom: 30px;
    font-size: 24px;
    letter-spacing: 2px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

/* 错误提示 - 深色背景下的红色提示 */
.error-tip {
    background-color: rgba(255, 77, 77, 0.2);
    color: #ff9494;
    padding: 10px 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    text-align: center;
    animation: shake 0.5s;
    border: 1px solid rgba(255, 77, 77, 0.3);
}

/* 错误抖动动画 */
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    10%, 30%, 50%, 70%, 90% { transform: translateX(-5px); }
    20%, 40%, 60%, 80% { transform: translateX(5px); }
}

/* 表单项目 */
.form-item {
    margin-bottom: 25px;
    position: relative;
}

.form-item label {
    display: block;
    color: #8892b0;
    margin-bottom: 8px;
    font-size: 14px;
    transition: all 0.3s ease;
}

.form-item input {
    width: 100%;
    padding: 12px 15px;
    background: rgba(10, 25, 47, 0.8);
    border: 1px solid rgba(136, 165, 191, 0.2);
    border-radius: 8px;
    color: #ccd6f6;
    font-size: 16px;
    transition: all 0.3s ease;
    outline: none;
}

/* 输入框聚焦效果 - 科技蓝高亮 */
.form-item input:focus {
    border-color: #64ffda;
    box-shadow: 0 0 0 3px rgba(100, 255, 218, 0.2);
    background: rgba(10, 25, 47, 0.9);
}

/* 输入框占位符样式 */
.form-item input::placeholder {
    color: #4a5568;
}

/* 登录按钮 - 深色系渐变按钮 */
.login-btn {
    width: 100%;
    padding: 12px;
    background: linear-gradient(90deg, #64ffda, #4cc9f0);
    border: none;
    border-radius: 8px;
    color: #0a192f;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.login-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: all 0.6s ease;
}

.remember-item {
    margin: 12px 0;
}

.remember-item input[type="checkbox"] {
    vertical-align: middle; /* 关键：让复选框和文字垂直居中对齐 */
    margin-right: 8px;
    cursor: pointer;
}

.remember-item label {
    vertical-align: middle; /* 关键：让标签和复选框垂直居中对齐 */
    cursor: pointer;
    font-size: 14px;
    color: #666;
}

/* 响应式调整 */
@media (max-width: 480px) {
    .login-box {
        padding: 30px 20px;
    }
    
    .login-box h2 {
        font-size: 24px;
    }
}