You have so many semantic elements at your disposal, but you aren’t using them.
<div id="main"> Make it a main element.
<div id="title"> Make it a header element.
<div id="img-div"> Can be a section element.
<div id="tribute-info"> Might be an article element.
<div id="footer"> Make it a footer element.
Use the for="" attribute on the labels with their values set to the corresponding input id.
align: center; is not a valid property, add cursor: pointer; to the button.
align: center; /* not valid */
cursor: pointer; /* add */
Move your break point to 830px, or at least no less then 650px
Other than the few little things, you did well. Good job.
Personal preference: I’m not crazy about the colors, their not horrible, but not great either. On the Tribute Page, they almost seem inappropriate (as in not fitting the theme of the page) to me. I guess it depends on the mood you are going for, but they seem a little too bright and happy and not, i don’t know, serious enough.