.custom-alert {
    display: none;
    position: fixed;
    top: 16px;
    left: 50%;
    transform: translateX(-50%);
    padding: 12px 24px;
    border-radius: 8px;
    z-index: 9999999;
    font-size: 14px;
    font-weight: 500;
    text-align: center;
    width: calc(100% - 64px);
    max-width: 420px;
    margin: 0 auto;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    opacity: 0;
    pointer-events: none;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    visibility: hidden;
}

/* 成功提示 */
.custom-alert.success {
    background-color: #f0fdf4;
    color: #166534;
    border: 1px solid #dcfce7;
}

.custom-alert.success::before {
    content: "✓";
    font-weight: bold;
}

/* 错误提示 */
.custom-alert.error {
    background-color: #fef2f2;
    color: #991b1b;
    border: 1px solid #fee2e2;
}

.custom-alert.error::before {
    content: "✕";
    font-weight: bold;
}

/* 警告提示 */
.custom-alert.warning {
    background-color: #fffbeb;
    color: #92400e;
    border: 1px solid #fef3c7;
}

.custom-alert.warning::before {
    content: "!";
    font-weight: bold;
}

/* 信息提示 */
.custom-alert.info {
    background-color: #f0f9ff;
    color: #075985;
    border: 1px solid #e0f2fe;
}

.custom-alert.info::before {
    content: "i";
    font-weight: bold;
    font-style: italic;
}

.custom-alert.show {
    visibility: visible;
    animation: alertIn 0.3s ease forwards, alertOut 0.3s ease 1.7s forwards;
}

@keyframes alertIn {
    0% {
        opacity: 0;
        transform: translate(-50%, -20px);
    }
    100% {
        opacity: 1;
        transform: translate(-50%, 0);
    }
}

@keyframes alertOut {
    0% {
        opacity: 1;
        transform: translate(-50%, 0);
    }
    100% {
        opacity: 0;
        transform: translate(-50%, -20px);
        visibility: hidden;
    }
}

/* 深色模式适配 */
@media (prefers-color-scheme: dark) {
    .custom-alert.success {
        background-color: rgba(22, 101, 52, 0.2);
        color: #86efac;
        border-color: #166534;
    }

    .custom-alert.error {
        background-color: rgba(153, 27, 27, 0.2);
        color: #fca5a5;
        border-color: #991b1b;
    }

    .custom-alert.warning {
        background-color: rgba(146, 64, 14, 0.2);
        color: #fcd34d;
        border-color: #92400e;
    }

    .custom-alert.info {
        background-color: rgba(7, 89, 133, 0.2);
        color: #7dd3fc;
        border-color: #075985;
    }
}

/* 移动端适配 */
@media (max-width: 480px) {
    .custom-alert {
        padding: 10px 16px;
        font-size: 13px;
    }
}