Minimal theme - WordPress

Some people only want to build their website from one slider. You could use this theme for it, because it's optimized, and won't load anything else, just a slider (if you don't have other plugins).

Go to your ftp, to the wp-content/themes folder and create a folder, which will be the name of your theme.

Create an index.php file with this code in it, just replace the slider's shortcode with yours:

<!DOCTYPE html>
<html <?php language_attributes(); ?>>
    <head>
    <meta charset="<?php bloginfo("charset"); ?>">
    <meta name="viewport" content="width=device-width">
    <link rel="profile" href="http://gmpg.org/xfn/11">
    <link rel="pingback" href="<?php bloginfo("pingback_url"); ?>">
    <link rel="stylesheet" href="<?php echo get_template_directory_uri(); ?>/style.css">
    <?php wp_head(); ?>
    </head>
    <body>
    <div id="container">
        <?php
            echo do_shortcode("[smartslider3 slider='1']");
        ?>
    </div>
    <?php wp_footer(); ?>
    </body>
</html>

Then create a style.css file, and put this code in it:

/*
 Theme Name:   minimal nextend
 Theme URI:    minimal nextend
 Text Domain:  minimal-nextend
*/

html, body{
    margin:0;
    padding:0;
}
#container{
    width:100%;
}

Now you can activate this theme from your backend.

If you would like to use more pages each containing a shortcode of a different slide, you could create an index.php file like this: 
<!DOCTYPE html>
<html <?php language_attributes(); ?>>
    <head>
    <meta charset="<?php bloginfo("charset"); ?>">
    <meta name="viewport" content="width=device-width">
    <link rel="profile" href="http://gmpg.org/xfn/11">
    <link rel="pingback" href="<?php bloginfo("pingback_url"); ?>">
    <link rel="stylesheet" href="<?php echo get_template_directory_uri(); ?>/style.css">
    <?php wp_head(); ?>
    </head>
    <body>
    <div id="container">
        <?php while ( have_posts() ) : the_post(); ?>
            <?php the_content(); ?>
        <?php endwhile;?>
    </div>
    <?php wp_footer(); ?>
    </body>
</html>

Minimal page template

Create a page template based on this WordPress tutorial: https://developer.wordpress.org/themes/template-files-section/page-template-files/ and put this content to the created PHP file:

<?php 
/**
 * Template Name: Minimal
 */
?>
<!DOCTYPE html>
<html <?php language_attributes(); ?>>
    <head>
    <meta charset="<?php bloginfo("charset"); ?>">
    <meta name="viewport" content="width=device-width">
    <link rel="profile" href="http://gmpg.org/xfn/11">
    <link rel="pingback" href="<?php bloginfo("pingback_url"); ?>">
    <link rel="stylesheet" href="<?php echo get_template_directory_uri(); ?>/style.css">
    <?php wp_head(); ?>
    </head>
    <body>
    <div id="container">
        <?php while ( have_posts() ) : the_post(); ?>
            <?php the_content(); ?>
        <?php endwhile;?>
    </div>
    <?php wp_footer(); ?>
    </body>
</html>