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,
.card-footer,
.card {
    background-color: transparent;
}

.card {
    background: rgba(255, 255, 255, 0.85);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
    border-radius: 16px;
    padding: 24px;
    transition: all 0.3s ease-in-out;
}

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

input,
#captchaBtn,
#submitBtn {
    box-shadow: 0 0 0 0 !important;
}

.form-label {
    margin-bottom: 0.15rem !important;
    font-size: 14px;
}

/* 错误信息隐藏 */
.error-msg-hidden {
    visibility: hidden;
}

/* 错误信息显示 */
.error-msg-show {
    visibility: visible;
}

/* 错误信息样式 */
.error-msg {
    color: #dc3545;
    font-size: 13px;
    margin: 0px auto 0px auto;
    max-width: 430px;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 5px;
    transition: opacity 0.2s ease-in-out;
}

/* 错误时输入框样式 */
.error-input {
    border-color: #dc3545;
    animation: shake 0.2s ease-in-out 0s 2;
}