problems with theme in header and divs

Because I am poor understanding of English, is there may be a mistake to answer, in which case, please point out easily if you can

First When Theme customize Please create a child theme

( While maintaining your customization, update the theme is enabled )

The creation method of a Child Theme

Child theme name:mysite

Creation of – theme holder
wp-content/themes/mysite
Creation of – stylesheet

style.css is created in the
wp-content/themes/mysite/style.css
The contents are as follows.
Creation of a style sheet
style.css

/*
Theme Name: mysite
Author: Your name
Author URI: http://yoursite.com
Version: 0.1
Template:raindrops
*/

Usually, when making a Child theme, it is explained that the style of a parent theme is imported as follows, but in rained Rops, it is unnecessary.
the child theme is detected and it imports automatically.

/* Raindrops No need import rules like below*/
@import url('../twentyten/style.css');

make file functions.php
ver1.200 ~

<?php

add_action( 'switch_theme', 'my_child_uninstall' );

function my_child_uninstall(){

    delete_option("raindrops_theme_settings");
}
?>

This description is intended to use in a child theme, and change settings of Raindrops, if you uninstall, delete the configuration changes of the parent theme.
If you did not delete, you may be when you install the new Raindrops, correct, it is not displayed by default.

Finish.

Change Site Title Font size

Add child themes style.css

#site-title span{
  font-size:/* your font size*/;
}

warning: invalid argument supplied foreach() in home/XXX/XXX etc the location of my files on line 1248

Please tell me home/XXX/XXX filename.

Thank you.

i am confused and frustrated.

Sorry

Also, why is the “more-link” putting in a number at the end of the entry name, such as you see here:

Dashbord / Appearance / Raindrops options / Accessibility Settings

Please set value no

Did not solve the problem of error in the header image related?

thank you.

my site are still small in firefox and IE.

I checked your site

Please see below capture

http://tenman.info/labo/snip/?attachment_id=4758

entry title still small ?

try below

add child theme /style.css

.entry-title span{
	font-size:20px;
}

Thank you.