html, body {
    height: 100%;
    overflow: hidden;
    margin: 0;
    padding: 0;
}


:root {
    --bg-main: #0f1a2b;
    --bg-header: #142238;
    --bg-sidebar: #16263f;
    --bg-content: #1c2f4a;
    --text-primary: #e8eef5;
    --text-secondary: #9bb0c9;
    --accent: #3da9fc;
    --accent-hover: #7cc8ff;
}

/* ROOT APP CONTAINER */
.app-shell {
    display: flex;
    flex-direction: column;
    height: 100vh;
    background: var(--bg-main);
    color: var(--text-primary);
    font-family: sans-serif;
}

/* HEADER */
.app-header {
    height: 60px;
    background: var(--bg-header);
    display: flex;
    align-items: center;
    padding: 0 20px;
    border-bottom: 1px solid #1f2f4a;
}

.app-title {
    font-size: 20px;
    font-weight: bold;
}

/* BODY */
.app-body {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* SIDEBAR */
.app-sidebar {
    width: 220px;
    background: var(--bg-sidebar);
    padding: 20px;
    border-right: 1px solid #1f2f4a;
    overflow-y: auto;
}

.nav-section-title {
    font-size: 12px;
    text-transform: uppercase;
    margin: 20px 0 10px;
    color: var(--text-secondary);
}

.nav-item {
    display: block;
    padding: 8px 0;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color 0.15s ease;
}

    .nav-item:hover {
        color: var(--accent-hover);
    }

    .nav-item.active {
        color: var(--accent);
        font-weight: bold;
    }


.app-content {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    background: var(--bg-content);
}