Having trouble making my website responsive : I'm working on a site for a school project that's due today and I have tried what seems like everything to make it responsive correctly and no matter what it doesn't resize correctly. I'm not that knowledgeable with coding to begin with, and worried since this is due soon. Can anyone help or point me in the right direction as to how to get this to work for mobile devices and stuff? Thanks in advance.

The following is the CSS

        body {font-family:arial;font-size:12px;cursor:default;color:#AAAAAA;
    }

    td {font-family:arial;font-size:12px;cursor:default;color:#242121
    }
    a {color:#000000;text-decoration:none;font-size:16px
    }
    a:hover {color:#000000;text-decoration:underline
    }
    input {border-width:1;font-family:arial;font-size:12px;padding:2px;height:21px;border-color:#000000;border-style:solid;background-color:#ffffff;color:#000000
    }
    .slogan{
    font-size:14px;color:#ffffff;padding:0 0 0 10;
    }
    .class1{
    font-size:18px;color:#ffffff;font-family:Times;
    }

The following is one of the web pages: index.html

        <!DOCTYPE html>
    <html lang="en">
    <head>
    <title>Litter of Love</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    
    <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1"/>
    
    <link rel="stylesheet" type="text/css" media="only screen and (max-device-width: 480px)" href="style-2.css" />

   
    <script>
      Alert("Welcome to my web page!") ;
    </script>
    
    </head>
  
    <body bgcolor="FFFFFF">
    <div align="center">
      <table width="750" border="0" cellpadding="0" cellspacing="0">
        <tr>
          <td colspan="3" width="750" height="200" background="header.jpg" valign="top" style="padding:0 0 0 10">
            <table width="700" border="0" cellpadding="0" cellspacing="0">

              <tr>
                <td width="330" class="slogan">

                  Build a Stylish Cat-Friendly Home

                </td>
                <td width="400" align="right">
                  <table width="400" border="0" cellpadding="0" cellspacing="0">
                    <tr>
                      <td align="right" height="20">

                      </td>
                    </tr>
                  </table>
                </td>
                <td width="20"></td>
              </tr>
            </table>
          </td>
        </tr>
        <tr>
          <td colspan="3" height="15" bgcolor="FFFFFF"></td>
        </tr>
        <tr>
          <td colspan="3" height="1" bgcolor="CCCCCC"></td>
        </tr>
        <tr>
          <td colspan="3" height="10" bgcolor="FFFFFF"></td>
        </tr>
        <tr>
          <td width="170" bgcolor="FFFFFF" valign="top">
            <span style="font-size:6px"><br></span>
            <div align="center">
              <table width="140" border="0" cellpadding="0" cellspacing="0">
                <tr>
                  <td><a href="index.html">Home</a></td>
                </tr>
            
                <tr>
                  <td height="5" bgcolor="#FFFFFF"></td>
                </tr>
                <tr>
                  <td><a href="contact.html">Contact us</a></td>
                </tr>

                <tr>
                  <td height="5" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td><a href="about.html">About us</a></td>
                </tr>

                <tr>
                  <td height="5" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td><a href="shop.html">Products</a></td>
                </tr>

                <tr>
                  <td height="5" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td><a href="media.html">Media</a></td>
                </tr>

              </table>
              <br><span style="font-size:6px"><br></span>

              <span style="font-size:6px"><br></span>
            </div>
          </td>
          <td width="1" bgcolor="CCCCCC"></td>
          <td width="579" valign="top">
            <span style="font-size:6px"><br></span>
            <div align="center">
              <table width="549" border="0" cellpadding="0" cellspacing="0">
                <tr>
                  <td colspan="4" height="1" bgcolor="AAAAAA"></td>
                  <td width="5" height="1" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td rowspan="2" colspan="2" width="542" height="27" bgcolor="#334a10" class="class1">&nbsp;&nbsp;HEALTHY</td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" height="4" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0" height="23"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" height="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" bgcolor="FFFFFF">
                    <table width="542" border="0" cellpadding="17" cellspacing="0">
                      <tr>
                        <td style="color:999999;line-height:1.6em">
                          <div align="justify"> 
                            <img src="healthy.jpg" width="350" height="200" align="left">
                            
                            Put together an engaging jungle gym for your cat friend and provide the gift of satisfaction and longevity.
                            <br><br>
                            Made by eco friendly materials and production recycled packaging.
                          </div>
                        </td>
                      </tr>
                    </table>
                  </td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" height="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" height="5" bgcolor="FFFFFF"></td>
                  <td width="4" height="5" bgcolor="FFFFFF"></td>
                  <td width="538" height="5" bgcolor="F0F0F0"></td>
                  <td width="1" height="5" bgcolor="F0F0F0"></td>
                  <td width="5" height="5" bgcolor="F0F0F0"></td>
                </tr>
              </table>
              <br>
              <table width="549" border="0" cellpadding="0" cellspacing="0">
                <tr>
                  <td colspan="4" height="1" bgcolor="AAAAAA"></td>
                  <td width="5" height="1" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td rowspan="2" colspan="2" width="542" height="27" bgcolor="#334a10" class="class1">&nbsp;&nbsp;FUNCTIONAL
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" height="4" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0" height="23"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" height="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" bgcolor="FFFFFF">
                    <table width="542" border="0" cellpadding="17" cellspacing="0">
                      <tr>
                        <td style="color:999999;line-height:1.6em">
                          <div align="justify"> 
                            <img src="functional.jpg"  width="350" height="200" align="right">
                            Captivating, durable and easy to relocate. Our cat furniture designs are a space conscious alternative to the traditional commercial cat tree.
                          </div>
                        </td>
                      </tr>
                    </table>
                  </td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" height="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" height="5" bgcolor="FFFFFF"></td>
                  <td width="4" height="5" bgcolor="FFFFFF"></td>
                  <td width="538" height="5" bgcolor="F0F0F0"></td>
                  <td width="1" height="5" bgcolor="F0F0F0"></td>
                  <td width="5" height="5" bgcolor="F0F0F0"></td>
                </tr>
              </table>
              <br>
              <table width="549" border="0" cellpadding="0" cellspacing="0">
                <tr>
                  <td colspan="4" height="1" bgcolor="AAAAAA"></td>
                  <td width="5" height="1" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td rowspan="2" colspan="2" width="542" height="27" bgcolor="#334a10" class="class1">&nbsp;&nbsp;MODERN</td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" height="4" bgcolor="FFFFFF"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0" height="23"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" height="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" bgcolor="FFFFFF">
                    <table width="542" border="0" cellpadding="17" cellspacing="0">
                      <tr>
                        <td style="color:999999;line-height:1.6em">
                          <div align="justify">
                            <img src="beautiful.jpg" width="350" height="200" align="left">

                            We believe furniture should be noticed, but not draw too much attention. We design conceps which spark conversation in any home, and yet stand the test of time. We are thrilled to see cats coming out of the unnoticed rooms and into your modern living room. 
                          </div>
                        </td>
                      </tr>
                    </table>
                  </td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td colspan="2" height="1" bgcolor="AAAAAA"></td>
                  <td width="1" bgcolor="AAAAAA"></td>
                  <td width="5" bgcolor="F0F0F0"></td>
                </tr>
                <tr>
                  <td width="1" height="5" bgcolor="FFFFFF"></td>
                  <td width="4" height="5" bgcolor="FFFFFF"></td>
                  <td width="538" height="5" bgcolor="F0F0F0"></td>
                  <td width="1" height="5" bgcolor="F0F0F0"></td>
                  <td width="5" height="5" bgcolor="F0F0F0"></td>
                </tr>
              </table>
              <span style="font-size:6px"><br></span>
            </div>
          </td>
        </tr>
        <tr>
          <td colspan="3" height="10" bgcolor="FFFFFF"></td>
        </tr>
        <tr>
          <td colspan="3" height="1" bgcolor="CCCCCC"></td>
        </tr>
        <tr>
          <td colspan="3" height="5" bgcolor="FFFFFF"></td>
        </tr>
        <tr>
          <td colspan="3" bgcolor="FFFFFF" align="right">
            Valco Copyright © 2017 All Rights Reserved 
          </td>
        </tr>
      </table>
    </div>
    </body>
    </html>