.help-modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

.help-modal-overlay.show {
    display: flex;
}

.help-modal-box {
    background: #fff;
    width: min(1000px, 94vw);
    height: min(760px, 90vh);
    border-radius: 10px;
    box-shadow: 0 15px 45px rgba(0, 0, 0, 0.25);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    animation: help-modal-in 0.2s ease-out;
}

@keyframes help-modal-in {
    from { transform: translateY(10px) scale(0.98); opacity: 0; }
    to   { transform: translateY(0) scale(1); opacity: 1; }
}

.help-modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 20px;
    background: #fff;
    color: #333;
    border-bottom: 1px solid #e0e0e0;
}

.help-modal-title {
    font-size: 15px;
    font-weight: 600;
    letter-spacing: 0.5px;
    color: #333;
}

.help-modal-close {
    background: transparent;
    border: none;
    color: #999;
    font-size: 22px;
    line-height: 1;
    cursor: pointer;
    padding: 0 6px;
    border-radius: 4px;
    transition: background 0.15s, color 0.15s;
}

.help-modal-close:hover {
    background: #f5f5f5;
    color: #333;
}

.help-modal-body {
    flex: 1;
    background: #fff;
    overflow: hidden;
}

#help-iframe {
    width: 100%;
    height: 100%;
    border: none;
    display: block;
}

/* 响应式：小屏幕占满大部分可视区域 */
@media (max-width: 640px) {
    .help-modal-box {
        width: 96vw;
        height: 92vh;
    }
}

/* 帮助页自定义弹窗（屏幕居中） */