.sidebar {
    width: var(--sidebar-width);
    min-height: 100%;
    background: linear-gradient(165deg, #0b1220 0%, #111a2e 45%, #172036 100%);
    color: #e2e8f0;
    display: flex;
    flex-direction: column;
    padding: 20px 0;
    transition: width 0.25s ease, transform 0.25s ease;
    overflow: hidden;
    z-index: 50;
    border-right: 1px solid rgba(148, 163, 184, 0.18);
    box-shadow: inset -1px 0 0 rgba(255, 255, 255, 0.04);
}

.sidebar-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 0 14px 24px;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
    font-weight: 700;
    color: #e2e8f0;
    letter-spacing: 0.2px;
}

.logo-badge {
    width: 30px;
    height: 30px;
    border-radius: 10px;
    background: linear-gradient(135deg, #60a5fa 0%, #2563eb 55%, #1d4ed8 100%);
    color: #ffffff;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 11px;
    font-weight: 800;
    box-shadow: 0 8px 18px rgba(37, 99, 235, 0.35);
}

.logo-full {
    color: #f8fafc;
    font-weight: 700;
}

.logo-mini {
    display: none;
    font-size: 13px;
    font-weight: 700;
    color: #93c5fd;
}

.nav-item {
    padding: 15px 25px;
    cursor: pointer;
    display: flex;
    align-items: center;
    font-size: 14px;
    border-left: 4px solid transparent;
    color: #cbd5e1;
    transition: 0.2s;
}

.nav-item:hover {
    background: linear-gradient(90deg, rgba(148, 163, 184, 0.14) 0%, rgba(148, 163, 184, 0.08) 100%);
    color: #f1f5f9;
}

.nav-item.active {
    background: linear-gradient(90deg, rgba(96, 165, 250, 0.24) 0%, rgba(59, 130, 246, 0.12) 100%);
    border-left-color: #7dd3fc;
    color: #e0f2fe;
}

.nav-icon {
    margin-right: 12px;
    width: 20px;
    text-align: center;
}

.nav-label {
    white-space: nowrap;
}

.sidebar-toggle {
    width: 36px;
    height: 36px;
    border: 1px solid rgba(203, 213, 224, 0.85);
    background: linear-gradient(180deg, #ffffff 0%, #f7fafc 100%);
    border-radius: 10px;
    cursor: pointer;
    color: #1f2937;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    line-height: 1;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px rgba(15, 23, 42, 0.12);
}

.sidebar-toggle:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(15, 23, 42, 0.2);
}

.sidebar-toggle:active {
    transform: translateY(0);
}

.sidebar .sidebar-toggle {
    border-color: rgba(99, 179, 237, 0.35);
    background: linear-gradient(135deg, #2d3748 0%, #1f2937 100%);
    color: #cfe9ff;
    box-shadow: 0 4px 14px rgba(17, 24, 39, 0.4);
}

.sidebar-mobile-toggle {
    display: none;
}

.sidebar-overlay {
    display: none;
}

body.theme-dark .sidebar {
    background: linear-gradient(165deg, #060b15 0%, #0b1220 45%, #10192b 100%);
    border-right-color: rgba(148, 163, 184, 0.2);
}

body.theme-dark .logo-badge {
    box-shadow: 0 10px 20px rgba(37, 99, 235, 0.4);
}

body.theme-dark .nav-item:hover,
body.theme-dark .nav-item.active {
    color: #e2e8f0;
}

body.theme-dark .sidebar-mobile-toggle {
    background: #111827;
    color: #e2e8f0;
    border-color: #475569;
}

@media (min-width: 769px) {
    .chat-mode.sidebar-collapsed .sidebar {
        width: var(--sidebar-collapsed-width);
    }

    .chat-mode.sidebar-collapsed .logo-full {
        display: none;
    }

    .chat-mode.sidebar-collapsed .logo-badge {
        display: none;
    }

    .chat-mode.sidebar-collapsed .logo-mini {
        display: inline;
    }

    .chat-mode.sidebar-collapsed .nav-label {
        display: none;
    }

    .chat-mode.sidebar-collapsed .nav-item {
        justify-content: center;
        padding: 15px 0;
    }

    .chat-mode.sidebar-collapsed .nav-icon {
        margin-right: 0;
    }

    .chat-mode.sidebar-collapsed .sidebar-top {
        flex-direction: column;
        gap: 10px;
        padding: 0 0 24px;
    }
}

@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        bottom: 0;
        transform: translateX(-100%);
        width: min(82vw, 280px);
    }

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

    .sidebar-overlay {
        position: fixed;
        inset: 0;
        background: rgba(0, 0, 0, 0.35);
        z-index: 45;
    }

    .chat-mode.sidebar-open .sidebar-overlay {
        display: block;
    }

    .sidebar-mobile-toggle {
        position: fixed;
        top: 12px;
        left: 12px;
        z-index: 46;
        display: none;
    }

    .chat-mode .sidebar-mobile-toggle {
        display: inline-flex;
    }

    .chat-mode.sidebar-open .sidebar-mobile-toggle {
        display: none;
    }
}