:root {
    color-scheme: light;
    --bg: #f4f6f8;
    --panel: #ffffff;
    --border: #d8dee7;
    --text: #172033;
    --muted: #667085;
    --primary: #2563eb;
    --shadow: 0 16px 40px rgba(15, 23, 42, 0.08);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    background: var(--bg);
    color: var(--text);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.app-shell {
    display: grid;
    grid-template-columns: 280px minmax(0, 1fr);
    min-height: 100vh;
}

.sidebar {
    border-right: 1px solid var(--border);
    background: #111827;
    color: #ffffff;
    padding: 24px 18px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: #ffffff;
    text-decoration: none;
    margin-bottom: 28px;
}

.brand__logo {
    width: 56px;
    height: 56px;
    object-fit: contain;
    flex: 0 0 auto;
}

.brand__text {
    display: grid;
    gap: 2px;
    min-width: 0;
}

.brand__title {
    color: #ffffff;
    font-size: 22px;
    font-weight: 800;
    line-height: 1.05;
}

.brand__subtitle {
    color: #8ca0bf;
    font-size: 12px;
    font-weight: 700;
    line-height: 1.25;
}

.tool-nav {
    display: grid;
    gap: 8px;
    min-height: calc(100vh - 112px);
}

.tool-nav__group {
    color: #8ca0bf;
    font-size: 12px;
    font-weight: 800;
    margin: 14px 12px 2px;
    text-transform: uppercase;
}

.tool-nav__item {
    display: block;
    border-radius: 6px;
    color: #d1d5db;
    padding: 11px 12px;
    text-decoration: none;
}

.tool-nav__item.is-active,
.tool-nav__item:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #ffffff;
}

.tool-nav__item--bottom {
    align-self: end;
    margin-top: auto;
    border: 1px solid rgba(148, 163, 184, 0.28);
    color: #ffffff;
}

.workspace {
    min-width: 0;
    padding: 28px;
}

@media (max-width: 980px) {
    .app-shell {
        grid-template-columns: 1fr;
    }

    .sidebar {
        border-right: 0;
        padding: 16px;
    }

    .brand {
        margin-bottom: 12px;
    }

    .brand__logo {
        width: 50px;
        height: 50px;
    }

    .workspace {
        padding: 18px;
    }
}