To change the Grafana dashboard theme from dark to light, you can follow these steps:

1. Through User Preferences:

   • Navigate to the bottom left corner of the Grafana UI, click on your user profile icon or username.
   • Select "Preferences" from the menu.
   • Under the "Preferences" section, you will find the "UI Theme" option.
   • Choose "Light" from the UI Theme dropdown menu^[1][2][3].

2. Through URL Parameter:

   • To switch to the light theme, append &theme=light to the Grafana dashboard URL in your browser ^[2:1].

3. Through Configuration File:

   • If you have access to the Grafana server configuration, you can set the default theme for all users by editing the grafana.ini file.
   • Locate the default_theme option and set it to light.
   • After making changes, restart the Grafana server to apply the new default theme^[2:2][4].

4. Through Docker Environment Configuration:

   • If you are running Grafana in a Docker container, you can set an environment variable GF_USERS_DEFAULT_THEME=light to change the default theme to light^[2:3].

5. Organization Preferences:

   • If you are an organization administrator, you can change the UI theme for all users in the organization.
   • Navigate to "Administration" in the left-side menu, click on "General", then click on "Default preferences".
   • In the "Preferences" section, select the UI theme as "Light"^[5].

Remember that individual user preferences will override organization or server-level settings. If you have previously set a theme at the user level, you will need to change it there to see the effect^[3:1].

For more advanced customizations, such as changing specific style characteristics or using a corporate color theme, you would need to edit the Sass files and recompile the Grafana frontend^[6]. However, this is a more complex process and typically not necessary for simply switching between the built-in dark and light themes.