2 added 5 characters in body
source | link

Add the your custom css in your theme folder

app/design/frontend/theme_name/package_name/Magento_Theme/layout/default_head_blocks.xml

app/design/frontend/theme_name/package_name/Magento_Theme/layout/default_head_blocks.xml

In default_head_blocks.xmldefault_head_blocks.xml file

    <page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <head>
      <!--  Add local resources -->

        <css src="css/main.css" />

    <!--  The following two ways to add local JavaScript files are equal     --> 
       <link src="js/bundle.js"/>

   <!-- Add external resources ->
   <css src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap-theme.min.css" src_type="url" />

 </head>
 </page>

Add the your custom css in your theme folder

app/design/frontend/theme_name/package_name/Magento_Theme/layout/default_head_blocks.xml

In default_head_blocks.xml file

    <page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <head>
      <!--  Add local resources -->

        <css src="css/main.css" />

    <!--  The following two ways to add local JavaScript files are equal     --> 
       <link src="js/bundle.js"/>

   <!-- Add external resources ->
   <css src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap-theme.min.css" src_type="url" />

 </head>
 </page>

Add the your custom css in your theme folder

app/design/frontend/theme_name/package_name/Magento_Theme/layout/default_head_blocks.xml

In default_head_blocks.xml file

    <page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <head>
      <!--  Add local resources -->

        <css src="css/main.css" />

    <!--  The following two ways to add local JavaScript files are equal     --> 
       <link src="js/bundle.js"/>

   <!-- Add external resources ->
   <css src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap-theme.min.css" src_type="url" />

 </head>
 </page>
1
source | link

Add the your custom css in your theme folder

app/design/frontend/theme_name/package_name/Magento_Theme/layout/default_head_blocks.xml

In default_head_blocks.xml file

    <page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <head>
      <!--  Add local resources -->

        <css src="css/main.css" />

    <!--  The following two ways to add local JavaScript files are equal     --> 
       <link src="js/bundle.js"/>

   <!-- Add external resources ->
   <css src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap-theme.min.css" src_type="url" />

 </head>
 </page>