:root {
    --bg: #f5f7fb;
    --panel: #ffffff;
    --line: #d7dce3;
    --text: #1f2328;
    --brand: #1a5fb4;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
    color: var(--text);
    background: var(--bg);
}

.wrap {
    min-height: 100vh;
    margin: 0;
    padding: 12px;
    display: grid;
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 12px;
}

.app-sidebar {
    border: 1px solid var(--line);
    border-radius: 10px;
    background: var(--panel);
    padding: 14px;
    min-height: calc(100vh - 24px);
}

.title {
    margin: 0;
    font-size: 22px;
}

.brand-block {
    padding-bottom: 14px;
    border-bottom: 1px solid var(--line);
    margin-bottom: 14px;
}

.nav-group {
    margin-top: 16px;
}

.nav-group-title {
    color: #697386;
    font-size: 12px;
    font-weight: 700;
    margin-bottom: 8px;
}

.nav-btn {
    width: 100%;
    border: 1px solid var(--line);
    background: var(--panel);
    color: var(--text);
    border-radius: 8px;
    padding: 10px 12px;
    cursor: pointer;
    font-size: 14px;
    text-align: left;
    margin-bottom: 8px;
}

.nav-btn.active {
    background: var(--brand);
    border-color: var(--brand);
    color: #fff;
}

.app-main {
    min-width: 0;
}

.pane {
    border: 1px solid var(--line);
    border-radius: 10px;
    overflow: hidden;
    background: var(--panel);
}

.pane.hidden {
    display: none;
}

.pane iframe {
    width: 100%;
    height: calc(100vh - 24px);
    border: 0;
    display: block;
    background: #fff;
}

@media (max-width: 860px) {
    .wrap {
        grid-template-columns: 1fr;
    }

    .app-sidebar {
        min-height: auto;
    }

    .nav-group {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
        gap: 8px;
    }

    .nav-group-title {
        grid-column: 1 / -1;
        margin-bottom: 0;
    }

    .nav-btn {
        margin-bottom: 0;
    }

    .pane iframe {
        height: calc(100vh - 220px);
        min-height: 620px;
    }
}