body {
    margin: 0;
    height: 100vh;
    background: linear-gradient(135deg,
            #f9f9f9 0%,
            #e4edf4 30%,
            #c9d6e3 60%,
            #a9bdd6 100%);
    font-family: "Noto Serif SC", serif;
    display: flex;
    justify-content: center;
    align-items: center;
}

.card-header,
.card-body {
    background: rgba(255, 255, 255, 0.85);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
    /* border-radius: 16px; */
    transition: all 0.3s ease-in-out;
}

.card-header h1 {
    gap: 10px;
    color: #2c3e50;
}


.login-card {
    width: 90%;
    max-width: 430px;
}


.xk-tabs {
    border-bottom: none;
    margin-bottom: 1rem;
}

.xk-tab-link {
    border: none;
    border-radius: 20px;
    padding: 0.5rem 1.5rem;
    margin: 0 0.5rem;
    background-color: #f0f4f8;
    color: #333;
    transition: all 0.3s ease;
}

.xk-tab-link:hover {
    background-color: #e0e7ef;
}

.xk-tab-link.active {
    background-color: #2a3d66;
    color: white;
    font-weight: 600;
}

@media (max-width: 576px) {
    .xk-tab-link {
        padding: 0.4rem 1rem;
        font-size: 14px;
    }
}

input {
    box-shadow: 0 0 0 0 !important;
}

.a-link a:hover {
    /* 去除链接下划线 */
    text-decoration: none;
}

.card-footer a {
    text-decoration: none;
}

.card-footer a:hover {
    text-decoration: underline;
}

.input-error {
    border: 1px solid #dc3545 !important;
    /* 红色边框 */
    box-shadow: 0 0 5px rgba(220, 53, 69, 0.5);
    /* 红色阴影 */
    animation: shake 0.2s ease-in-out 0s 2;
    /* 抖动动画 */
}

@keyframes shake {
    0% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-5px);
    }

    50% {
        transform: translateX(5px);
    }

    75% {
        transform: translateX(-5px);
    }

    100% {
        transform: translateX(0);
    }
}

@media (max-width: 576px) {
    .login-card {
        width: 90%;
    }

    h1 {
        font-size: 1.5rem;
    }

    .error-message-small,
    .a-link {
        font-size: 11px;
    }
}

.error-message-small {
    color: #dc3545;
    font-size: 13px;
    margin: -5px auto 10px auto;
    max-width: 300px;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 5px;
    transition: opacity 0.2s ease-in-out;
}

#loginBtn:hover {
    background-color: #1a57c2;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(0, 123, 255, 0.3);
}