/* == SIDEBAR == */
.sidebar {
    width: var(--sidebar-width);
    background: var(--surface);
    border-right: 1px solid rgba(13,41,112,0.07);
    padding: 2rem 1.5rem;
    padding-top: 84px;
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 1030;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
}

.sidebar-brand-label {
    font-family: var(--font-primary);
    font-weight: 800;
    color: var(--navy);
    font-size: 0.95rem;
}

.sidebar-sub {
    font-size: 0.62rem;
    text-transform: uppercase;
    letter-spacing: 0.16em;
    color: var(--text-muted);
    margin-top: 2px;
}

.sidebar-nav {
    list-style: none;
    padding: 0;
    margin: 0;
}

    .sidebar-nav li {
        margin-bottom: 2px;
    }

    .sidebar-nav .nav-link {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        padding: 0.75rem 1rem;
        border-radius: 0.5rem;
        font-size: 0.63rem;
        font-weight: 700;
        text-transform: uppercase;
        letter-spacing: 0.12em;
        color: var(--text-muted);
        position: relative;
        transition: color .2s, background .2s, transform .15s;
        text-decoration: none;
    }

        .sidebar-nav .nav-link:hover {
            color: var(--navy);
            background: var(--navy-soft);
        }

        .sidebar-nav .nav-link.active {
            background: var(--surface-white);
            color: var(--navy);
            box-shadow: 0 1px 6px rgba(13,41,112,0.1);
            transform: translateX(4px);
        }

            .sidebar-nav .nav-link.active::before {
                content: '';
                position: absolute;
                left: 0;
                width: 3px;
                height: 60%;
                background: var(--cyan);
                border-radius: 0 2px 2px 0;
            }

        .sidebar-nav .nav-link .material-symbols-outlined {
            font-size: 1.15rem;
        }

        .sidebar-nav .nav-link.nav-locked {
            opacity: 0.4;
            cursor: not-allowed;
            pointer-events: none;
        }

.btn-save-progress {
    background: linear-gradient(135deg, var(--navy), var(--navy-mid));
    color: #fff;
    font-family: var(--font-primary);
    font-weight: 700;
    font-size: 0.82rem;
    border-radius: 0.5rem;
    border: none;
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-top: auto;
    box-shadow: 0 4px 16px rgba(13,41,112,0.25);
    transition: opacity .2s, transform .1s;
}

    .btn-save-progress:hover {
        opacity: 0.88;
    }

    .btn-save-progress:active {
        transform: scale(0.97);
    }

/* Sidebar mobile backdrop */
.sidebar-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(13,41,112,0.3);
    z-index: 1029;
}

@media (max-width: 991.98px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform .3s ease;
        box-shadow: 4px 0 24px rgba(13,41,112,0.15);
        padding: 1.25rem 1.1rem;
        padding-top: 72px;
    }

        .sidebar.is-open {
            transform: translateX(0);
        }

    .sidebar-nav .nav-link {
        padding: 0.55rem 0.75rem;
    }

    .btn-save-progress {
        padding: 0.6rem 0.9rem;
        margin-top: 1rem;
    }

    .sidebar-backdrop.is-open {
        display: block;
    }

    .main-content {
        margin-left: 0 !important;
    }
}