:root {
    --sidebar-width: 180px;
    --sidebar-width-large: 200px;
    --sidebar-width-mobile: 70px;
}

.sidebar {
    width: var(--sidebar-width);
    height: 100vh;
    min-height: 100vh;
    background: linear-gradient(180deg, #ffffff 0%, #fafbfc 100%);
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    padding: 20px 0;
    box-shadow: 4px 0 20px rgba(0, 0, 0, 0.06);
    position: fixed;
    left: 0;
    top: 0;
    z-index: 100;
    border-right: 1px solid rgba(0, 0, 0, 0.04);
    box-sizing: border-box;
}

.sidebar .logo {
    margin-bottom: 24px;
    width: 100%;
    display: flex;
    justify-content: center;
}

.sidebar .logo-icon {
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, #f75444 0%, #ff7875 100%);
    border-radius: 14px;
    box-shadow: 0 6px 20px rgba(247, 84, 68, 0.35);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.sidebar .logo-icon:hover {
    transform: rotate(10deg) scale(1.05);
    box-shadow: 0 8px 28px rgba(247, 84, 68, 0.45);
}

.sidebar .nav-menu {
    display: flex;
    flex-direction: column;
    gap: 4px;
    width: 100%;
    padding: 0 8px;
    align-items: center;
    flex: 1;
    overflow-y: auto;
}

.sidebar .nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    width: calc(100% - 16px);
    max-width: 160px;
    padding: 12px 14px;
    color: #6b7280;
    text-decoration: none;
    border-radius: 12px;
    transition: all 0.3s ease;
    cursor: pointer;
    background: none;
    border: none;
    font-size: 14px;
    box-sizing: border-box;
    justify-content: flex-start;
}

.sidebar .nav-item:hover {
    background: #f3f4f6;
    color: #374151;
}

.sidebar .nav-item.active {
    background: #fef5f5;
    color: #f75444;
}

.sidebar .nav-item svg {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

.sidebar .nav-divider {
    height: 1px;
    background: #e5e7eb;
    margin: 12px 0;
    width: 100%;
}

.sidebar .user-section {
    margin-top: auto;
    padding: 16px 14px;
    margin: auto 0 8px;
    box-sizing: border-box;
    background: linear-gradient(180deg, rgba(247,84,68,0.05) 0%, rgba(255,120,117,0.05) 100%);
    border-radius: 16px;
    width: calc(100% - 16px);
    max-width: 160px;
}

.sidebar .user-avatar {
    margin-bottom: 12px;
    display: flex;
    justify-content: center;
}

.sidebar .avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: linear-gradient(135deg, #f75444 0%, #ff7875 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #ffffff;
    font-size: 18px;
    font-weight: 600;
}

.sidebar .avatar.guest {
    background: linear-gradient(135deg, #9ca3af 0%, #d1d5db 100%);
}

.sidebar .user-info {
    text-align: center;
}

.sidebar .user-name {
    font-size: 14px;
    font-weight: 500;
    color: #1f2937;
    margin-bottom: 4px;
}

.sidebar .user-role {
    font-size: 12px;
    color: #9ca3af;
}

.sidebar .login-btn {
    width: 100%;
    padding: 10px;
    background: linear-gradient(135deg, #f75444 0%, #ff7875 100%);
    border: none;
    border-radius: 12px;
    color: #ffffff;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    margin-top: 12px;
    transition: all 0.3s ease;
}

.sidebar .login-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(247, 84, 68, 0.4);
}

.sidebar .logout-btn {
    width: 100%;
    padding: 10px;
    background: #f3f4f6;
    border: none;
    border-radius: 12px;
    color: #6b7280;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    margin-top: 12px;
    transition: all 0.3s ease;
}

.sidebar .logout-btn:hover {
    background: #e5e7eb;
}

.sidebar .recharge-link {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 14px;
    background: linear-gradient(135deg, #f75444 0%, #ff7875 100%);
    border-radius: 12px;
    color: #ffffff;
    text-decoration: none;
    transition: all 0.3s ease;
    margin: 4px 0;
    cursor: pointer;
    box-sizing: border-box;
    width: calc(100% - 16px);
    max-width: 160px;
}

.sidebar .recharge-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(247, 84, 68, 0.4);
}

.sidebar .recharge-link svg {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

.sidebar .recharge-link span {
    font-size: 14px;
    font-weight: 500;
}

@media (min-width: 1920px) and (max-width: 2559px) {
    .sidebar {
        width: var(--sidebar-width-large);
        padding: 24px 0;
    }
    
    .sidebar .logo-icon {
        width: 48px;
        height: 48px;
        border-radius: 16px;
    }
    
    .sidebar .nav-item {
        padding: 14px 16px;
        font-size: 15px;
        max-width: 170px;
    }
    
    .sidebar .nav-item svg {
        width: 20px;
        height: 20px;
    }
    
    .sidebar .avatar {
        width: 52px;
        height: 52px;
        font-size: 20px;
    }
    
    .sidebar .user-section {
        max-width: 170px;
        padding: 20px 16px;
    }
    
    .sidebar .recharge-link {
        padding: 14px 16px;
        max-width: 170px;
    }
    
    .sidebar .recharge-link svg {
        width: 20px;
        height: 20px;
    }
    
    .sidebar .recharge-link span {
        font-size: 15px;
    }
}

@media (min-width: 2560px) {
    .sidebar {
        width: calc(var(--sidebar-width) * 1.3);
        padding: 28px 0;
    }
    
    .sidebar .logo-icon {
        width: 56px;
        height: 56px;
        border-radius: 18px;
    }
    
    .sidebar .nav-item {
        padding: 16px 18px;
        font-size: 16px;
        max-width: 190px;
        gap: 14px;
    }
    
    .sidebar .nav-item svg {
        width: 22px;
        height: 22px;
    }
    
    .sidebar .avatar {
        width: 56px;
        height: 56px;
        font-size: 22px;
    }
    
    .sidebar .user-section {
        max-width: 190px;
        padding: 24px 18px;
    }
    
    .sidebar .user-name {
        font-size: 15px;
    }
    
    .sidebar .user-role {
        font-size: 13px;
    }
    
    .sidebar .login-btn,
    .sidebar .logout-btn {
        padding: 12px;
        font-size: 15px;
    }
    
    .sidebar .recharge-link {
        padding: 16px 18px;
        max-width: 190px;
        gap: 14px;
    }
    
    .sidebar .recharge-link svg {
        width: 22px;
        height: 22px;
    }
    
    .sidebar .recharge-link span {
        font-size: 16px;
    }
}

@media (max-width: 768px) {
    .sidebar {
        width: var(--sidebar-width-mobile);
        padding: 20px 0;
    }

    .sidebar .nav-item span {
        display: none;
    }

    .sidebar .recharge-link span {
        display: none;
    }

    .sidebar .user-section {
        display: none;
    }
    
    .sidebar .nav-item {
        justify-content: center;
        max-width: 48px;
    }
    
    .sidebar .recharge-link {
        justify-content: center;
        max-width: 48px;
    }
}