.sidebar {
    width: 280px;
    flex-shrink: 0;
    position: sticky;
    top: calc(var(--header-height) + 20px);
    height: calc(100vh - var(--header-height) - 40px);
    overflow-y: auto;
    padding: 8px 4px 20px 0;
    border-left: 1px solid var(--border);
    background: transparent;
    z-index: 1060;
    display: flex;
    flex-direction: column;
    scrollbar-width: thin;
    transition: all var(--transition);
}

.sidebar::-webkit-scrollbar {
    width: 4px;
}
.sidebar::-webkit-scrollbar-track {
    background: transparent;
}
.sidebar::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 10px;
}
.sidebar::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.sidebar nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1px;
    padding-right: 4px;
}

.sidebar .nav-group {
    margin-top: 12px;
}
.sidebar .nav-group:first-child {
    margin-top: 0;
}
.sidebar .nav-group-title {
    font-size: 0.6rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-weight: 700;
    padding: 6px 12px 8px;
    opacity: 0.4;
    transition: opacity var(--transition);
    position: relative;
    display: flex;
    align-items: center;
    gap: 8px;
}
.sidebar .nav-group-title::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
    opacity: 0.3;
}

.sidebar a {
    padding: 7px 14px;
    border-radius: 10px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    font-weight: 400;
    position: relative;
    background: transparent;
    border: none;
}

.sidebar a::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%) scaleY(0);
    width: 3px;
    height: 20px;
    background: var(--primary);
    border-radius: 0 4px 4px 0;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.sidebar a .nav-icon {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    background: var(--code-bg);
    color: var(--text-secondary);
    font-size: 0.8rem;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    flex-shrink: 0;
}

.sidebar a .nav-label {
    flex: 1;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.sidebar a:hover {
    background: var(--code-bg);
    color: var(--text);
    transform: translateX(-4px);
}
.sidebar a:hover .nav-icon {
    background: var(--primary);
    color: var(--bg);
    transform: scale(1.05);
}

.sidebar a.active {
    background: var(--bg) !important;
    color: var(--text) !important;
    font-weight: 600;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.04);
    transform: translateX(-4px);
}
.sidebar a.active::before {
    transform: translateY(-50%) scaleY(1);
}
.sidebar a.active .nav-icon {
    background: var(--primary);
    color: var(--bg);
}

[data-theme="dark"] .sidebar a.active {
    background: rgba(255, 255, 255, 0.05) !important;
    color: var(--text) !important;
    box-shadow: 0 2px 12px rgba(255, 255, 255, 0.02);
}
[data-theme="dark"] .sidebar a.active .nav-icon {
    background: #ffffff;
    color: #000000;
}
[data-theme="dark"] .sidebar a.active::before {
    background: #ffffff;
}

.sidebar a:active {
    transform: scale(0.96);
}
.sidebar-footer {
    display: none;
}

@media (max-width: 1024px) {
    .sidebar {
        position: fixed;
        top: 0;
        right: 0;
        bottom: 0;
        width: 300px;
        max-width: 80vw;
        height: 100vh;
        border-left: none;
        border-right: none;
        transform: translateX(100%);
        transition: transform 0.45s cubic-bezier(0.22, 1, 0.36, 1),
                    opacity 0.3s ease,
                    background var(--transition);
        padding: 20px 18px 24px;
        box-shadow: -8px 0 40px rgba(0, 0, 0, 0.15);
        z-index: 1060;
        background: rgba(var(--bg-rgb, 255, 255, 255), 0.97);
        overflow-y: auto;
        border-radius: 0;
        backdrop-filter: blur(24px);
        -webkit-backdrop-filter: blur(24px);
        opacity: 0;
        pointer-events: none;
        will-change: transform, opacity;
        padding-top: 70px;
    }
    .sidebar.open {
        transform: translateX(0);
        opacity: 1;
        pointer-events: auto;
    }
    [data-theme="dark"] .sidebar {
        background: rgba(18, 18, 18, 0.96);
        box-shadow: -8px 0 40px rgba(0, 0, 0, 0.6);
    }

    .sidebar-inner {
        display: flex;
        flex-direction: column;
        height: 100%;
    }
    .sidebar nav {
        flex: 1;
        padding-bottom: 20px;
        padding-right: 4px;
    }

    .sidebar a .nav-icon {
        display: none;
    }

    .sidebar .nav-group {
        margin-top: 18px;
    }
    .sidebar .nav-group:first-child {
        margin-top: 0;
    }
    .sidebar .nav-group-title {
        font-size: 0.6rem;
        letter-spacing: 0.1em;
        padding: 6px 12px 8px;
        color: var(--text-secondary);
        opacity: 0.5;
        font-weight: 700;
        border-bottom: 1px solid var(--border);
        margin-bottom: 4px;
    }
    .sidebar a {
        padding: 10px 16px;
        font-size: 0.95rem;
        border-radius: 12px;
        margin-bottom: 2px;
        transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
        border: none;
        background: transparent;
        position: relative;
        font-weight: 450;
        color: var(--text-secondary);
        transform: none;
    }
    .sidebar a::after {
        content: '';
        position: absolute;
        left: 0;
        top: 50%;
        transform: translateY(-50%);
        width: 3px;
        height: 0;
        background: var(--primary);
        border-radius: 0 4px 4px 0;
        transition: height 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .sidebar a.active::after {
        height: 60%;
    }
    .sidebar a:hover {
        background: var(--code-bg);
        transform: translateX(-4px);
        color: var(--text);
    }
    .sidebar a:active {
        transform: scale(0.97);
    }
    .sidebar a.active {
        background: var(--bg) !important;
        color: var(--text) !important;
        font-weight: 700;
        border: none !important;
        box-shadow: none !important;
        transform: translateX(-4px);
    }
    [data-theme="dark"] .sidebar a.active {
        background: #ffffff !important;
        color: #000000 !important;
        border: none !important;
        box-shadow: none !important;
    }
    .sidebar a.active::after {
        height: 60%;
    }
    .sidebar a .nav-label {
        flex: 1;
    }

    .sidebar-footer {
        display: flex !important;
        border-top: 1px solid var(--border);
        padding-top: 18px;
        margin-top: 6px;
        flex-direction: column;
        gap: 8px;
        padding-bottom: 8px;
    }
    .sidebar-footer .theme-toggle,
    .sidebar-footer .lang-toggle {
        border-radius: 12px;
        padding: 10px 16px;
        font-size: 0.9rem;
        border: 1px solid var(--border);
        background: var(--code-bg);
        transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
        color: var(--text);
        font-weight: 450;
    }
    .sidebar-footer .theme-toggle:hover,
    .sidebar-footer .lang-toggle:hover {
        background: var(--primary);
        color: var(--bg);
        border-color: var(--primary);
        transform: translateX(-4px);
    }
    .sidebar-footer .theme-toggle i,
    .sidebar-footer .lang-toggle i {
        font-size: 1.1rem;
        width: 20px;
        text-align: center;
    }
    .sidebar-footer .github-link {
        border-radius: 12px;
        padding: 10px 16px;
        font-size: 0.9rem;
        background: var(--primary);
        color: var(--bg);
        border: 1px solid var(--primary);
        font-weight: 500;
        transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
        justify-content: center;
        gap: 8px;
    }
    .sidebar-footer .github-link:hover {
        background: var(--primary-hover);
        border-color: var(--primary-hover);
        transform: translateX(-4px);
        text-decoration: none;
        color: var(--bg);
    }
    .sidebar-footer .github-link i {
        font-size: 1.1rem;
    }
}

@media (max-width: 600px) {
    .sidebar {
        width: 260px;
        max-width: 85vw;
        padding: 16px 14px 20px;
        padding-top: 60px;
    }
    .sidebar a {
        font-size: 0.88rem;
        padding: 8px 14px;
        border-radius: 10px;
    }
    .sidebar .nav-group-title {
        font-size: 0.55rem;
        padding: 4px 10px 6px;
    }
    .sidebar-footer .theme-toggle,
    .sidebar-footer .lang-toggle,
    .sidebar-footer .github-link {
        font-size: 0.82rem;
        padding: 8px 14px;
    }
}

@media (max-width: 400px) {
    .sidebar {
        width: 220px;
        max-width: 90vw;
        padding: 12px 10px 16px;
        padding-top: 56px;
    }
    .sidebar a {
        font-size: 0.82rem;
        padding: 6px 12px;
        border-radius: 8px;
    }
    .sidebar .nav-group-title {
        font-size: 0.5rem;
        padding: 2px 8px 4px;
    }
    .sidebar-footer .theme-toggle,
    .sidebar-footer .lang-toggle,
    .sidebar-footer .github-link {
        font-size: 0.75rem;
        padding: 6px 12px;
    }
}

@media (width: 390px) and (max-height: 844px) {
    .sidebar {
        width: 250px;
        padding-top: 60px;
    }
    .sidebar a {
        font-size: 0.85rem;
        padding: 8px 14px;
    }
}